Digital PDFs

EK-DFM16-UG-001

January 1986

294 pages

Original

9.8MB

Document:	DFM Series Intelligent Communications Processor User Guide
Order Number:	EK-DFM16-UG
Revision:	001
Pages:	294
Original Filename:

OCR Text

EK-OFM 16-UG-001

DFM Series
Intelligent
Communications
Processor
User Guide

Prepared by Educational Services
of
Digital Equipment COiporation

1st Edition, January 1986

AU Rights Reserved

The information in this document is subject to change without notice and should
not be construed as a commitment by Digital Equipment Corporation. Digital
Equipment Corporation assumes no responsibility for any errors that may
appear in this document

Printed in U. S.A.

The following are trademarks of Digital Equipment Corporation:

~DmDDmD

DEC
DECmate
DECset
DECsystem-lO
DECSYSTEM-20
DECUS

DECwriter
DIBOL
MASSBUS
PDP
P/OS
Professional
Rainbow
RSTS

RSX
Scholar
ULTRIX
UNIBUS
VAX
VMS
VT
Work Processor

CONTENTS
Page
PREFACE
CHAPTER 1

INTRODUCTION

1.1
1.2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.2.6
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5

MULTIPLEXING ••••••••••••••••••••••••••••••••••••••• 1-1
DFM FEATURES ••••••••••••••••••••••••••••••••••••••• 1-4
Channel Switching and Port Contention •••••••••••• 1-4
Network Management and Contro1 ••••••••••••••••••• 1-5
Intelligent Interfacing •••••••••••••••••••••••••• 1-7
Comprehensive Diagnostics •••••••••••••••••••••••• 1-8
Expansion Capabi1ity ••••••••••••••••••••••••••••• 1-8
Maximized Throughput ••••••••••••••••••••••••••••• 1-9
APPLICATIONS AND CONFIGURATIONS ••••••••••••••••••• 1-11
Switching and Contention •••••••••••••••••••••••• 1-11
Tail Circuits ••••••••••••••••••••••••••••••••••• 1-14
Satellite Links ••••••••••••••••••••••••••••••••• 1-17
Synchronous Channels •••••••••••••••••••••••••••• 1-18
Multiple DFM Configuration •••••••••••••••••••••• 1-18

CHAPTER 2

PREINSTALLATION PLANNING

2.1
2.2
2.3
2.3.1
2.3.1.1
2.3.1.2
2.3.1.3
2.3.1.4
2.3.2
2.3.3
2.4
2.4.1
2.4.2
2.5
2.5.1
2.5.2
2.6
2.6.1
2.6.2
2.7
2.8
2.9
2.9.1
2.9.2
2.10

GENE RA L. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 2-1
SUPERVISORY CHANNEL •••••••••••••••••••••••••••••••• 2-1
CHANNEL CONSIDERATIONS ••••••••••••••••••••••••••••• 2-2
Channel Type ••••••••••••••••••••••••••••••••••••• 2-2
Asynchronous Channels •••••••••••••••••••••••••• 2-2
Switched Channels •••••••••••••••••••••••••••••• 2-2
Synchronous Channels ••••••••••••••••••••••••••• 2-3
Unused Channels •••••••••••••••••••••••••••••••• 2-4
Connecting a DFM Channel to a Modem •••••••••••••• 2-4
Channel Cabling ••• ~ •••••••••••••••••••••••••••••• 2-4
LINK CONSIDERATIONS •••••••••••••••••••••••••••••••• 2-4
Type of Link ••••••••••••••••••••••••••••••••••••• 2-4
Data Rate for the Link ••••••••••••••••••••••••••• 2-5
LINK MODEMS •••••••••••••••••••••••••••••••••••••••• 2-8
Optional Integral Modem •••••••••••••••••••••••••• 2-8
External Link Modems or Line Drivers ••••••••••••• 2-8
OPERATING CONDITIONS FOR THE DFM UNIT •••••••••••••• 2-9
Env ironment •••••••••••••••••••••••••••••••••••••• 2-9
Power Requirements ••••••••••••••••••••••••••••••• 2-9
PREINSTALLATION TEST AND FAMILIARIZATION ••••••••••• 2-9
DFM CABLES •••••••••••••••••••••••••••••••••••••••• 2-l0
PREINSTALLATION EQUIPMENT SELECTION ••••••••••••••• 2-12
Using the Hardware Selection Guide •••••••••••••• 2-13
Determining DFM Size •••••••••••••••••••••••••••• 2-16
INVENTORY AND REQUIREMENTS FORM ••••••••••••••••••• 2-17

iii

CONTENTS (Cont)

Page
CHAPTER 3

INSTALLATION

3.1
3.2
3.3
3.3.1
3.3.2
3.3.3
3.3.4
3.4
3.4.1
3.4.2
3.4.3
3.5

3.5.2
3.5.3
3.5.4
3.6
3.6.1
3.6.2
3.6.2.1
3.6.2.2

GENE RA L. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 3-1
UNPACKING AND INSPECTION ••••••••••••••••••••••••••• 3-l
VISUAL INSPECTION •••••••••••••••••••••••••••••••••• 3-l
Removing the Bezel ••••••••••••••••••••••••••••••• 3-l
Checking the Identification Decal •••••••••••••••• 3-l
Checking the Modules ••••••••••••••••••••••••••••• 3-3
Rear Panel Connectors •••••••••••••••••••••••••••• 3-4
CONTROLS AND INDICATORS •••••••••••••••••••••••••••• 3-6
Control Module ••••••••••••••••••••••••••••••••••• 3-6
Channel Expansion Module ••••••••••••••••••••••••• 3-6
Integral Modem Module •••••••••••••••••••••••••••• 3-6
PREINSTALLATION BENCHTEST AND OPERATOR
FAMILIARIZATION ••••••••••••••••••••••••••••••••••• 3-l8
Logging on with USER and SYSTEM MANAGER Level
Passwords ••••••••••••••••••••••••••••••••••••••• 3-l8
Setting System Parameters ••••••••••••••••••••••• 3-20
Entering Data Channel Command Mode •••••••••••••• 3-24
Switched Channel Operation •••••••••••••••••••••• 3-25
INSTALLATION •••••••••••••••••••••••••••••••••••••• 3-28
DFM Cabling ••••••••••••••••••••••••••••••••••••• 3-29
Installing Module Options ••••••••••••••••••••••• 3-29
Installing Integral Modems •••••••••••••••••••• 3-30
Installing Channel Expansion Modules •••••••••• 3-3l

CHAPTER 4

USING THE DFM UNIT

4.1
4.2
4.3
4.3.1
4.3.2

INTRODUCTION ••••••••••••••••••••••••••••••••••••••• 4-l
UNSWITCHED CHANNELS •••••••••••••••••••••••••••••••• 4-l
SWITCHED CHANNELS •••••••••••••••••••••••••••••••••• 4-2
Remote Switching Application ••••••••••••••••••••• 4-2
Local Switching Application •••••••••••••••••••••• 4-8

CHAPTER 5

COMMAND DESCRIPTIONS

5.1
5.2
5.3
5.4
5.4.1
5.4.2
5.5

GENERAL •••••••••••••••••••••••••••••••••••••••••••• 5-l
SUPERVISORY COMMAND HANDLER •••••••••••••••••••••••• 5-l
DATA CHANNEL COMMAND MODE •••••••••••••••••••••••••• 5-l
DFM COMMAND STRUCTURE •••••••••••••••••••••••••••••• 5-2
Command Levels ••• ~ ••••••••••••••••••••••••••••••• 5-2
DFM Command Prompting •••••••••••••••••••••••••••• 5-3
DFM COMMAND DESCRIPTIONS ••••••••••••••••••••••••••• 5-5

3.5.1

CONTENTS (Cont)
Page
CHAPTER 6

SELECTING CONFIGURATION OPTIONS

6.1
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
6.3
6.3.1
6.3.2
6.3.2.1
6.3.2.2
6.3.2.3
6.3.2.4
6.4
6.5
6.5.1
6.5.2
6.5.3
6.5.4
6.5.5
6.5.6
6.5.7
6.5.8
6.5.9
6.6
6.6.1
6.6.2
6.7
6.7.1
6.7.2
6.7.3
6.7.3.1
6.7.3.2
6.8
6.8.1
6.8.2
6.8.2.1
6.8.2.2
6.8.2.3
6.8.2.4
6.8.2.5
6.8.2.6
6.8.2.7
6.8.2.8

DFM CONFIGURATION OPTIONS •••••••••••••••••••••••••• 6-1
THE CONFIGURATION WORKSHEET •••••••••••••••••••••••• 6-1
Network Security ••••••••••••••••••••••••••••••••• 6-2
System Management •••••••••••••••••••••••••••••••• 6-2
Synchronous/DDCMP Support •••••••••••••••••••••••• 6-3
Modem Tail Circuits •••••••••••••••••••••••••••••• 6-3
Data PBX Faci1ity •••••••••••••••••••••••••••••••• 6-3
Asynchronous Channel Support ••••••••••••••••••••• 6-3
Host Systems ••••••••••••••••••••••••••••••••••••• 6-3
PROGRAMMING GUIDELINES ••••••••••••••••••••••••••••• 6-9
Configuration Rules •••••••••••••••••••••••••••••• 6-9
Using the SET Command ••••••••••••••••••••••••••• 6-10
Setting Multiple Options •••••••••••••••••••••• 6-10
Abbreviations ••••••••••••••••••••••••••••••••• 6-11
"Channel All" programming ••••••••••••••••••••• 6-11
COpy Command •••••••••••••••••••••••••••••••••• 6-12
DFM OPTIONS AND VALUES •••••••••••••••••••••••••••• 6-12
SETTING SYSTEM OPTIONS •••••••••••••••• : ••••••••••• 6-16
Name Option ••••••••••••••••••••••••••••••••••••• 6-16
Type Option ••••••••••••••••••••••••••••••••••••• 6-16
Configuration Option •••••••••••••••••••••••••••• 6-16
System Autodisconnect (AUTODISC) Option ••••••••• 6-17
Switched-Data Parity (DATAPAR) Option ••••••••••• 6-18
Switched-Stopbits Option •••••••••••••••••••••••• 6-18
Switched-Signals Option ••••••••••••••••••••••••• 6-18
Command Character (COMCHAR) Option •••••••••••••• 6-19
Default Option •••••••••••••••••••••••••••••••••• 6-21
SETTING LINK OPTIONS •••••••••••••••••••••••••••••• 6-22
Link Speed Option ••••••••••••••••••••••••••••••• 6-22
Link Delay Option ••••••••••••••••••••••••••••••• 6-23
IMPORTANT CHANNEL CONSIDERATIONS •••••••••••••••••• 6-23
EIA Signals on DFM Channels ••••••••••••••••••••• 6-23
Connecting Modems to DFM Channels ••••••••••••••• 6-24
Flow Control on DFM Channels •••••••••••••••••••• 6-25
Out-of-Band Flow Control •••••••••••••••••••••• 6-26
In-Band Flow Control •••••••••••••••••••••••••• 6-27
SETTING CHANNEL OPTIONS ••••••••••••••••••••••••••• 6-28
Channel Type Option ••••••••••••••••••••••••••••• 6-28
Asynchronous Channel Options •••••••••••••••••••• 6-31
Asynchronous Speed •••••••••••••••••••••••••••• 6-31
Asynchronous Flow Control ••••••••••••••••••••• 6-31
Asynchronous Data parity •••••••••••••••••••••• 6-31
Asynchronous Stopbits ••••••••••••••••••••••••• 6-32
Asynchronous Signals •••••••••••••••••••••••••• 6-32
Asynchronous Fil1character •••••••••••••••••••• 6-33
Asynchronous Priority ••••••••••••••••••••••••• 6-33
Asynchronous Echo ••••••••••••••••••••••••••••• 6-34

CONTENTS (Cont)
Page
6.8.2.9
6.8.2.10
6.8.2.11
6.8.3
6.8.3.1
6.8.3.2
6.8.3.3
6.8.3.4
6.8.3.5
6.8.3.6
6.8.3.7
6.8.3.8
6.8.3.9
6.8.3.10
6.8.3.11
6.8.4
6.8.4.1
6.8.4.2
6.8.4.3
6.8.4.4

Asynchronous Messages ••••••••••••••••••••••••• 6-34
Asynchronous Command Terminal (COMTERM) ••••••• 6-35
Asynchronous Command Echo (COMECHO) ••••••••••• 6-36
Switched Channel Options •••••••••••••••••••••••• 6-36
Switched Speed •••••••••••••••••••••••••••••••• 6-36
Switched Flow Control ••••••••••••••••••••••••• 6-37
Switched Signa1s •••••••••••••••••••••••••••••• 6-37
Switched Fillcharacter •••••••••••••••••••••••• 6-39
Switched Priority ••••••••••••••••••••••••••••• 6-40
Switched Echo ••••••••••••••••••••••••••••••••• 6-40
Switched Messages ••••••••••••••••••••••••••••• 6-40
Switched Command Terminal (COMTERM) ••••••••••• 6-41
Switched Command Echo (COMECHO) ••••••••••••••• 6-41
Switched Channel ID/Group Access •••••••••••••• 6-41
Switched Automatic Disconnect (AUTODISC) •••••• 6-44
Synchronous and DDCMP Channel Options ••••••••••• 6-44
Synchronous Speed ••••••••••••••••••••••••••••• 6-44
Synchronous Flow Control •••••••••••••••••••••• 6-45
Synchronous Blocksize ••••••••••••••••••••••••• 6-45
Synchronous SYNFILL ••••••••••••••••••••••••••• 6-45

CHAPTER 7

TROUBLESHOOTING AND TESTING

7.1
7.2
7.3
7.4
7.4.1
7.4.1.1
7.4.1.2

GENERAL •••••••••••••••••••••••••••••••••••••••••• ~.7-1
AUTOMATIC SELF-TESTS ••••••••••••••••••••••••••••••• 7-2
DFM UNIT FAILS AUTOMATIC SELF-TEST ••••••••••••••••• 7-5
LINK Oij CHANNEL COMPONENTS ••••••••••••••••••••••••• 7-8
Isolating and Testing Link Components •••••••••••• 7-9
End-to-End LBACK Test ••••••••••••••••••••••••• 7-11
Remote Modem Digital Loopback (Using
DFM Pattern) •••••••• ~ ••••••••••••••••••••••••• 7-14
Remote Modem Digital Loopback (Using
Modem Pattern) •••••••••••••••••••••••••••••••• 7-16
Remote Modem Analog Loopback (Using DFM
Pattern) •••••••••••••••••••••••••••••••••••••• 7-18
Remote Modem Analog Loopback (Using Modem
Pattern) •••••••••••••••••••••••••••••••••••••• 7-20
Local Analog Loopback (Using DFM Pattern) ••••• 7-22
Local Analog Loopback (Using Modem Pattern) ••• 7-24
Link Signals Test ••••••••••••••••••••••••••••• 7-26
Isolating and Testing Channel Components •••••••• 7-28
Channel Configuration Pitfalls •••••••••••••••• 7-28
Channel Monitoring Facilities ••••••••••••••••• 7-29
Channel Errors •••••••••••••••••••••••••••••••• 7-30
Local and Remote Echo Tests ••••••••••••••••••• 7-30
Channel Pattern Test •••••••••••••••••••••••••• 7-32
Channel Signals Test •••••••••••••••••••••••••• 7-33

7.4.1.3
7.4.1.4
7.4.1.5
7.4.1.6
7.4.1.7
7.4.1.8
7.4.2
7.4.2.1
7.4.2.2
7.4.2.3
7.4.2.4
7.4.2.5
7.4.2.6

CONTENTS (Cont)
Page
APPENDIX A

DFM FUNCTIONAL SPECIFICATIONS

APPENDIX B

LINK MODEMS

B.1
B.2
B.3
B.4
B.5
B.5.1
B.5.2
B.6
B.6.1
B.6.2

LINK MODEM OVERVIEW •••••••••••••••••••••••••••••••• B-1
LINK MODEM CONFIGURATIONS WITH THE DFM UNIT •••••••• B-1
THE DF124 LINK MODEM ••••••••••••••••••••••••••••••• B-4
THE DF126 LINK MODEM ••••••••••••••••••••••••••••••• B-9
THE DF127 LINK MODEM •••••••••••••••••••••••••••••• B-14
DF127 Version 1 Configuration Options ••••••••••• B-15
DF127 Version 2 and 3 Configuration Options ••••• B-17
THE DF129 LINK MODEM •••••••••••••••••••••••••••••• B-25
DF129 Version 1 Configuration Options ••••••••••• B-26
DF129 Version 2 and 3 Configuration Options ••••• B-28

APPENDIX C

CABLES

C.1
C.2
C.3
C.4
C.5
C.6

GENERAL •••••••••••••••••••••••••••••••••••••••••••• C-1
CABLE E (BC22E) DFM TO ASYNCHRONOUS DTE •••••••••••• C-2
CABLE F (BC22F) DFM TO SYNCHRONOUS DTE ••••••••••••• C-3
CABLE L (BC22L) SPECIAL DIRECT LINK •••••••••••••••• C-4
CABLE M (BC22M) DCE TO DCE CROSSOVER ••••••••••••••• C-5
CABLE T SPECIAL LOOPBACK TEST CABLE •••••••••••••••• C-6

APPENDIX D CONFIGURATION WORKSHEET
APPENDIX E

SIGNAL CHARACTERISTICS

E.1
E.2
E.3
E.4

INTRODUCTION ••••••••••••••••••••••••••••••••••••••• E-1
CONCENTRATED LINK SIGNAL CHARACTERISTICS ••••••••••• E-2
CHANNEL SIGNALS INTERFACE CHARACTERISTICS •••••••••• E-4
SIGNAL CHARACTERISTICS FOR ASYNCHRONOUS AND
SWITCHED CHANNEL TYPES ••••••••••••••••••••••••••••• E-7
Assert Mode •••••••••••••••••••••••••••••••••••••• E-7
Pass Mode •••••••••••••••••••••••••••••••••••••••• E-8
Dial Mode ••••••••••••••••••••••••••••••••••••••• E-10
Dia1* Mode •••••••••••••••••••••••••••••••••••••• E-12
Assert* Mode •••••••••••••••••••••••••••••••••••• E-14
Asynchronous CTS-RTS F1ow ••••••••••••••••••••••• E-15
DSR-DTR F1ow •••••••••••••••••••••••••••••••••••• E-16
CTSx-RLSx F1ow •••••••••••••••••••••••••••••••••• E-17
SIGNAL CHARACTERISTICS FOR SYNCHRONOUS AND DDCMP
CHANNEL TYPES ••••••••••••••••••••••••••••••••••••• E-18
No Flow Control ••••••••••••••••••••••••••••••••• E-18
Synchronous CTS-RTS Flow •••••••••••••••••••••••• E-19

E.4.1
E.4.2
E.4.3
E.4.4
E.4.5
E.4.6
E.4.7
E.4.8
E.5
E.5.1
E.5.2

vii

CONTENTS (Cont)
Page
APPENDIX F

INCOMPATIBILITIES OF SOFTWARE LEVEL 1.9 WITH
LATER RELEASES

F.l
F.2
F.3
F.4
F.5
F.6

F.12

INTRODUCTION ••••••••••••••••••••••••••••••••••••••• F-l
HALF-/FULL-DUPLEX DDCMP •••••••••••••••••••••••••••• F-l
SATELLITE DELAY •••••••••••••••••••••••••••••••••••• F-l
MULTILINE BROADCAST MESSAGES ••••••••••••••••••••••• F-l
INDEFINITE REPEAT •••••••••••••••••••••••••••••••••• F-l
ABILITY TO SET A CHANNEL TYPE TO ·UNUSED· WITHOUT
LOSING PARAMETERS •••••••••••••••••••••••••••••••••• F-2
SWITCHED CONNECTION FROM SUPERVISORY CHANNEL ••••••• F-2
GROUP ·NAMES" •••••••••••••••••••••••••••••••••••••• F-2
SYSTEM WARNING FOR COMMANDS THAT RESTART
THE SYSTEM ••••••••••••••••••••••••••••••••••••••••• F-2
ABILITY TO SET SPEEDS SEPARATELY FOR EITHER END
FOR SYNCHRONOUS CHANNELS ••••••••••••••••••••••••••• F-3
ADDITIONAL ASYNCHRONOUS CHANNEL FLOW CONTROL
SELECTIONS ••••••••••••••••••••••••••••••••••••••••• F-3
SWITCHED CHANNEL "DIAL-UP" OPTION NOW CALLED

F.13

COMMAND CHARACTER (COMCHAR) •••••••••••••••••••••••• F-4

F.7
F.8
F.9
F.IB
F.ll

n SIGNALS n • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • F-3

INDEX

FIGURES
Figure No.
1-1
1-2
1-3
1-4
1-5
1-6
1-7
1-8
1-9
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8

Title

Page

Traditional Remote Communication Network ••••••••••• 1-2
DFM ICP Communication Network •••••••••••••••••••••• 1-3
Switching and Contention Configuration •••••••••••• l-12
Single-Unit Switching Functions ••••••••••••••••••• 1-13
Distributed DFM Network with Dial-up Remotes •••••• 1-14
Dial-up Computer Timesharing •••••••••••••••••••••• 1-16
DFM System Using Satellite Link ••••••••••••••••••• 1-17
Synchronous Channel Configuration ••••••••••••••••• 1-18
Multiple DFM Configuration •••••••••••••••••••••••• l-19
DFM Cable Connections ••••••••••••••••••••••••••••• 2-lB
Hardware Selection Guide •••••••••••••••••••••••••• 2-12
Hardware Selection Guide for Example 2-1 •••••••••• 2-13
Hardware Selection Guide for Example 2-2 •••••••••• 2-14
Hardware Selection Guide for Example 2-3 •••••••••• 2-14
Hardware Selection Guide for Example 2-4 •••••••••• 2-15
Hardware Selection Guide for Example 2-5 •••••••••• 2-15
DFM Sizing Aid •••••••••••••••••••••••••••••••••••• 2-16

viii

FIGURES (Cont)
Figure No.
2-9
3-1
3-2
3-3
3-4
3-5
3-6
4-1
4-2
4-3
6-1
6-2
7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
7-10
7-11
B-1
B-2
8-3
B-4
B-5
B-6
B-7
B-8
B-9
8-10
C-l
C-2
C-3
C-4
C-5

Title

Page

Inventory and Requirements Form ••••••••••••••••••• 2-l7
DFM Enclosure, Module Placement, and ID Decal •••••• 3-2
DFM Rear Panel Connectors •••••••••••••••••••••••••• 3-5
Control Module Pushbuttons and LEDs ••••••••••••••• 3-11
Line Module Indicators •••••••••••••••••••••••••••• 3-l2
Modem Module Pushbuttons and LEDs ••••••••••••••••• 3-l3
Integral Modem Link Connections ••••••••••••••••••• 3-22
Typical Asynchronous Configuration ••••••••••••••••• 4-l
Typical Remote Switched Configuration •••••••••••••• 4-3
Local Switching Application •••••••••••••••••••••••• 4-9
Sample Configuration Diagram ••••••••••••••••••••••• 6-4
Sample of Completed Configuration Worksheet •••••••• 6-5
End-to-End Link Loop Configuration •••••••••••••••• 7-ll
Remote Digital Loopback (Using DFM Pattern) ••••••• 7-14
Remote Digital Loopback (Using Modem Pattern) ••••• 7-16
Remote Analog Loopback (Using DFM Pattern) •••••••• 7-18
Remote Analog Loopback (Using Modem Pattern) •••••• 7-20
Local Analog Loopback (Using DFM Pattern) ••••••••• 7-22
Local Analog Loopback (Using Modem Pattern) ••••••• 7-24
Link Signals Test Configuration ••••••••••••••••••• 7-27
Channel Echo Test Configuration ••••••••••••••••••• 7-3l
Channel Pattern Test Configuration •••••••••••••••• 7-32
Channel Signals Test Configuration •••••••••••••••• 7-33
Standalone Link Modem Connections •••••••••••••••••• B-2
Integral Modem Link Connections •••••••••••••••••••• B-3
DF124-AM Module Layout and Switchpack Locations •••• B-4
DF126-AM Module Layout and Switchpack Locations •••• B-9
DF127-AM Module (Version 1) Layout and Switchpack
Locations ••••••••••••••••••••••••••••••••••••••••• B-15
DF127-AM Module (Version 2) Layout and Switchpack
Locations ••••••••••••••••••••••••••••••••••••••••• B-17
DF127-AM Module (Version 3) Layout and Switchpack
Locations ••••••••••••••••••••••••••••••••••••••••• B-18
DF129-AM Module (Version 1) Layout and Switchpack
Locations ••••••••••••••••••••••••••••••••••••••••• B-26
DF129-AM Module (Version 2) Layout and Switchpack
Locations ••••••••••••••••••••••••••••••••••••••••• B-28
DF129-AM Module (Version 3) Layout and Switchpack
Locations ••••••••••••••••••••••••••••••••••••••••• B-29
BC22E Cable
DFM to Asynchronous DTE ••••••••••••• C-2
BC22F Cable -- DFM to Synchronous DTE •••••••••••••• C-3
BC22L Cable -- Direct Link ••••••••••••••••••••••••• C-4
BC22M Cable -- DCE to DCE Crossover •••••••••••••••• C-5
Special Signals Loopback Test Cable •••••••••••••••• C-6

EXAMPLES
Example No.
2-1
2-2
2-3
2-4
2-5
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
5-11
5-12
5-13
5-14
5-15
5-16
5-17
5-18
5-19
5-20
5-21
5-22
5-23
5-24
5-25
5-26
5-27
5-28
5-29
5-30
5-31
5-32
5-33
5-34
5-35
5-36

Title

Page

Channel Connections ••••••••••••••••••••••••••••••• 2-13
Supervisory Command Channel (SCC) Connections ••••• 2-14
Direct Link Connections (No Modems) ••••••••••••••• 2-14
Link Connections with Integral Modems ••••••••••••• 2-15
Link Connections with External Modems ••••••••••••• 2-15
Using RETURN at the SYS> Prompt •••••••••••••••••••• 5-3
Using RETURN After the First Valid Entry ••••••••••• 5-3
Using RETURN After the Second Valid Entry •••••••••• 5-3
Using RETURN After the Third Valid Entry ••••••••••• 5-4
Using RETURN After the Fourth Valid Entry •••••••••• 5-4
Broadcast Message •••••••••••••••••••••••••••••••••• 5-5
Canceling a Test Sequence •••••••••••••••••••••••••• 5-6
Using the CLEAR Command •••••••••••••••••••••••••••• 5-7
Connecting from a Switched Data Channel •••••••••••• 5-9
Connecting from the Supervisory Channel •••••••••••• 5-9
Connecting from the Supervisory Channel
(Channel Busy) •••••••••••••••••••••••••••••••••••• 5-10
Connecting from a Switched Data Channel (Channel
Queued or Busy) ••••••••••••••••••••••••••••••••••• 5-10
Copy One Channel to All Channels •••••••••••••••••• 5-11
Disconnecting from Switched Data Channels ••••••••• 5-12
Disconnecting a Local Channel Using the
Supervisory Channel ••••••••••••••••••••••••••••••• 5-13
Disconnecting a Local Channel Using the
Supervisory Channel ••••••••••••••••••••••••••••••• 5-13
Logging Out •••••••••••• ~ •••••••••••••••••••••••••• 5-15
Monitor System •••••••••••••••••••••••••••••••••••• 5-16
Monitor Link •••••••••••••••••••••••••••••••••••••• 5-17
Monitor Channel ••••••••••••••••••••••••••••••••••• 5-18
Repeat Monitoring a Channel ••••••••••••••••••••••• 5-20
System Restart •••••••••••••••••••••••••••••••••••• 5-21
Setting Time •••••••••••••••••••••••••••••••••••••• 5-22
Setting Date •••••••••••••••••••••••••••••••••••••• 5-23
Setting Alarm ••••••••••••••••••••••••••••••••••••• 5-23
Setting New Passwords ••••••••••••••••••••••••••••• 5-23
Assigning Group Names ••••••••••••••••••••••••••••• 5-24
Show System ••••••••••••••••••••••••••••••••••••••• 5-25
Show Link ••••••••••••••••••••••••••••••••••••••••• 5-26
Show Channel •••••••••••••••••••••••••••••••••••••• 5-26
Show Switched ••••••••••••••••••••••••••••••••••••• 5-27
Show Group •••••••••••••••••••••••••••••••••••••••• 5-27
Switched Channel Status ••••••••••••••••••••••••••• 5-29
Using the Data Channel Supervisory Command •••••••• 5-30
Using the TERMTEST Pattern Test ••••••••••••••••••• 5-3l
Using the Link LBACK Test ••••••••••••••••••••••••• 5-33

EXAMPLES (Cont)
Example No.
6-1
6-2
6-3
6-4
6-5
7-1

Title

Page

Setting Multiple Options •••••••••••••••••••••••••• 6-1l
Set Channel All ••••••••••••••••••••••••••••••••••• 6-l1
Programming with the COpy Command ••••••••••••••••• 6-12
Setting Group ID/Access ••••••••••••••••••••••••••• 6-42
Assigning Group Name •••••••••••••••••••••••••••••• 6-43
Running L8ACK from the Supervisory Channel •••••••• 7-13
TA8LES

Table No.
2-1
3-1
3-2
3-3
3-4
3-5
3-6
3-7
5-1
5-2
6-1
6-2
6-3
6-4
6-5
6-6
6-7
7-1
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
8-11
8-12
8-13
8-14
8-15
8-16
8-17

Title

page

Cable Descriptions and Order Numbers •••••••••••••• 2-ll
Slot/Channel Combinations •••••••••••••••••••••••••• 3-4
Control Module Pushbutton Controls ••••••••••••••••• 3-7
Control Module LED Indicators •••••••••••••••••••••• 3-9
Channel Module LED Indicators ••••••••••••••••••••• 3-l1
Link Modem Front Panel Switches/LED Matrix •••••••• 3-14
Link Modem Front Panel LED Indicators ••••••••••••• 3-1S
Link Modern Front Panel Pushbutton Controls •••••••• 3-17
Link State Indicators ••••••••••••••••••••••••••••• S-28
Channel State Indicators •••••••••••••••••••••••••• 5-28
Configuration Options •••••••••••••••••••••••••••••• 6-2
Configuration Options and Values •••••••••••••••••• 6-l3
Command Character Selections •••••••••••••••••••••• 6-20
Option Default Values ••••••••••••••••••••••••••••• 6-21
DFM Flow Control Selections ••••••••••••••••••••••• 6-26
DFM Flow Control Selection Chart •••••••••••••••••• 6-28
Alarm Messages •••••••••••••••••••••••••••••••••••• 6-34
Link Modern Loopback Test Matrix •••••••••••••••••••• 7-9
DFM Link Modems •••••••••••••••••••••••••••••••••••• 8-l
DF124-AM Switchpack 1 Selections ••••••••••••••••••• 8-5
DF124-AM Switchpack 2 Selections ••••••••••••••••••• b-6
DF124-AM Switchpack 3 Selections ••••••••••••••••••• 8-7
DF124-AM Switchpack 4 Selections ••••••••••••••••••• B-8
DF126-AM Switchpack 1 Selections •••••••••••••••••• B-10
DF126-AM Switchpack 2 Selections •••••••••••••••••• B-l1
DF126-AM Switchpack 3 Selections •••••••••••••••••• B-12
DF126-AM Switchpack 4 Selections •••••••••••••••••• B-12
DF126-AM Switchpack 5 Selections •••••••••••••••••• 8-13
DF126-AM Switchpack 6 Selections •••••••••••••••••• 8-13
Switchpack Options •••••••••••••••••••••••••••••••• 8-16
Analog Output Attenuation ••••••••••••••••••••••••• 8-16
Jumper Selections for Version 2 ••••••••••••••••••• 8-19
Jumper Selections for Version 3 ••••••••••••••••••• 8-20
DF127-AM Switchpack 1 Selections for Version 2 •••• 8-21
DF127-AM Switchpack 1 Selections for Version 3 •••• 8-22

TABLE (Cont)
Table No.
8-18
8-19
8-20
8-21
8-22
8-23
8-24
8-25
8-26
E-l
E-2
E-3
E-4
E-5
E-6
E-7
E-8
E-9
E-10
E-ll
E-12

Title

Page

DFI27-AM Switchpack 2 Selections
(Versions 2 and 3) •••••••••••••••••••••••••••••••• 8-23
DFI27-AM Switchpack 3 Selections
(Versions 2 and 3) •••••••••••••••••••••••••••••••• 8-24
Switchpack Options •••••••••••••••••••••••••••••••• 8-27
Analog Output Attenuation ••••••••••••••••••••••••• 8-27
Jumper Selections for Version 2 ••••••••••••••••••• 8-30
Jumper Selections for Version 3 ••••••••••••••••••• 8-31
DFI29-AM Switchpack 1 Selections •••••••••••••••••• 8-32
DFI29-AM Switchpack 2 Se1ections •••••••••••••••••• 8-33
DF129-AM Switchpack 3 Selections •••••••••••••••••• B-34
Concentrated Link Signal Characteristics ••••••••••• E-2
Channel Signal Characteristics (General) ••••••••••• E-4
Assert Mode Signal Characteristics ••••••••••••••••• E-7
Pass Mode Signal Characteristics ••••••••••••••••••• E-8
Dial Mode Signal Characteristics •••••••••••••••••• E-10
Dial* Mode Signal Characteristics ••••••••••••••••• E-12
Assert* Mode Signal Characteristics ••••••••••••••• E-l4
Asynchronous CTS-RTS Signal Characteristics ••••••• E-l5
DSR-DTR Signal Characteristics •••••••••••••••••••• E-l6
CTSx-RTSx Signal Characteristics •••••••••••••••••• E-17
Signal Characteristics Without Flow Control ••••••• E-l8
Synchronous CTS-RTS Signal Characteristics •••••••• E~19

xii

PREFACE
This manual provides technical information that allows the user to
install,
test,
program,
and
operate
the
DFM
Intell igent
Communications Processor.
Chapter 1 provides a general description of the important
features of the DFM unit and summarizes a variety of DFM
applications and configurations.
Chapter 2 contains procedures for proper site setup and
prelnstallation planning.
Important link considerations and
unit cabling requirements are covered.
Chapter 3 describes the physical features of the DFM unit and
details the different controls and indicators of each module
that mounts in the DFM enclosure. This chapter also includes a
comprehensive preinstallation benchtest that verifies system
and link operation, and allows the operator to become familiar
with some of the features and functions of the DFM unit.
Chapter 4 provides typical examples of DFM configurations and
the steps necessary to program the DFM unit properly to
implement those configurations.
Chapter 5 contains detailed descriptions of each DFMcommand,
where used, and the command I ine format for executing each
command. Examples are provided for each command.
Chapter 6 describes the many configuration options that are
ava i lable wi th the DFM uni t to set up system, channel, and
link parameters.
Chapter 7 identifies actions that should be taken when service
is required.
A systematic troubleshooting procedure using
various DFM test features is provided to isolate problems with
the hardware or telephone facilities.
Appendices A through F include a variety of material from
specifications, details of all possible link modems, cables, a
blank Configuration Worksheet, signal characteristics, and
release notes.
This manual uses red and blue color highlighting to bring
attention
to
certain
features,
operator
interactions,
and
conditions. Many of the examples in this manual show how the
operator must interact with the DFM unit to program certain
operational characteristics. In these examples, operator input is
highlighted in red, while expected system responses are printed in
bl ue.
Other areas of this manual are pr inted in bl ue to emphasi ze the
importance of certain information.

xiii

CHAPTER 1
INTRODUCTION

1.1 MULTIPLEXING
A multiplexer allows multiple terminals to share a pair of modems
and a telephone line.

Each multiplexer controls the incoming data flow from local
channels by combining it into a single stream of data for
transmission to the other unit. Likewise, each unit receives a
stream of
data
from
the
other
uni t,
determines
channel
destinations, and forwards the data to the individual local
channel destinations.
The original method for linking several devices at one site to a
computer at another site is shown in Figure 1-1.
Each device
requires its own telephone line and two modems, one at each
location. In the illustration, a total of ten modems and five
separate telephone lines are required.
Phone line usage is
ineff ic ient and costl y in te rms of monthly charges.
Al so, the
large number of modems represent a high purchase or monthly rental
expense.
Multiplexers solve the cost problem of multiple modems and phone
lines otherwise required to connect several remotely located
terminals to long distance or local area networks.
The DFM system can replace the configuration of Figure 1-1 wi th
both reduced costs and greater efficiency.
Two DFM units, two
modems, and one high-speed telephone line (Figure 1-2) can service
multiple terminals as well as provide other valuable network
management benefits.
The DFM unit monitors the usage and performance of each channel as
well as the concentrated link.
It can print or display error
counts and statistics on utilization for each channel or the link.
Additional cost savings and efficiency are realized because the
DFM Intelligent Communications Processor (ICP) is an intelligent
interfacing device. The DFM unit connects previously incompatible
devices, provides automatic error correction, and manages the
entire network from one location.
Aggregate baud rate of devices connected to the DFM unit can
typically be two to four times the concentrated link speed.
In
some applications, baud rates up to eight or ten times the
concentrated link speed can be achieved.

1-1

TERMINAL

~~PERSONAL
COMPUTER

COMPUTER

TERMINAL

PERSONAL
COMPUTER
TK·10651

Figure 1-1

Traditional Remote Communication Network

1-2

PERSONAL
COMPUTER

TERMINAL

-",
@.
I
,

,
,

PRINTER

SUPERVISORY
COMMAND
CHANNEL (seC)

rr=Q,
--}-,

PRINTER

~
TERMINAL

TK-10(if;6

Figure 1-2

DFM rcp Commun ication Network

1-3

1.2 DFM FEATURES
A conventional multiplexer channel can communicate only with
devices attached to the same channel on the remote unit.
This
type of operation is called dedicated.
Other devices cannot
access a dedicated channel even when it is inactive.
The DFM ICP eliminates the limitation of dedicated channels by
allowing any channel in the network to be connected to any other
channel. Multiple channels at one location can contend for a
limited number of computer ports or other facilities at the other
end of the system. Channel switching and port contention provide
the flexibility that is required in today's rapidly changing
communications environment.
The modular design permits quick and easy removal or insertion of
modules into the backplane.
No tools are requi red, which speeds
troubleshooting, simplifies field upgrades, and decreases down
time for maintenance.
DFM flexibility is a key feature. Programmable configuration
options adapt the units to most types of data communications
requirements and independent channel configurations allow the
units to interface between nearly any type of bit serial devices.
The
DFM
unit
supports
both
synchronous
and
asynchronous
communications traffic.
Two out of every group of four channels
can support either Digital Equipment Corporation's DDCMP or other
synchronous protocols. Synchronous protocols other than DDCMP are
handled in a transparent mode.
1.2.1 Channel Switching and Port Contention
DFM handling of switched channels allocates valuable computer
ports more efficiently, services a greater range of hardware
facilities, and provides easy expansion to support additional
users.
Switched channel ends are treated
independently.
A device
connected to a switched channel on the local unit may communicate
with any device connected to the local or remote unit.
If a
selected channel or all channels assigned to a group are busy, the
request for connection is queued. The connection is made as soon
as the requested channel or any other channel assigned to the same
group is available.
The contention feature of switched channels enables sharing of a
limited number of computer ports or other facilities among a
var iety of users.
Thi s feature allows a l6-channel uni t to be
connected to a uni t wi th fewer ports, wi th channels at one end
contending for connections on a first come, first served basis.
Channel switching and contention includes an automatic disconnect
feature for channels when there has been no activity within a
time-out period defined by the system manager.

1-4

1.2.2 Network Management and Control
Management of the DFM system is accomplished through interactive
commands that are entered ~o the system through the supervisory
channel. Programming, diagnostic testing, and monitoring of the
system are accomplished by the supervisory command program, which
is directly accessed by the supervisory channel. If desired, t~e
supervisory channel can be dialed into from a remote location.
Nondisruptive, current data information can be disPlared or
printed by the supervisory channel using the monitor capab lities
for channel, link, or system. Monitored information for channels
includes four types of error counters, EIA signal status, the last
characters transmitted and
received by the terminal,
and
transmit/receive utilization statistics.
Monitor information for the link and system includes link error
counters, EIA signals, link transmit/receive utilization, and
system status indicators.
This vital information enables the user to analyze data traffic
trends and potential congestion points.
It also isolates the
location and nature of error conditions. For example, widely
fluctuating link statistics can provide an early warning of
telephone line failure.
When telephone line performance is
questionable, link categories can be monitored (and printed out)
over time to help define a link problem before it causes the
system to go down.
A full range of diagnostic tests quickly
isolates malfunctioning components to replaceable modules.
Supervisory Channel
The supervisory channel provides direct access to the
supervisory command program, which processes DFM interactive
commands. The supervisory command program may also be accessed
from the data channels once they are enabled to do so by the
system manager.
Supervisory channel
output
takes
full
advantage of CRT display capabilities, displaying a full
screen of system information on request.
Down-line Loading of Parameters
When units are reset, reinitialized, or reconnected, channel
parameters are checked for consistency and down-line loaded,
if necessary. This not only ensures parameter compatibility
between units, but also speeds the initial configuration
process.
Channel parameters need to be entered on only one
unit, and then sent down-line to the other.

1-5

Selective Modem Control
The integral modem module permits switch selectable modem
control and single source support of the DFM system. When the
front
panel
signal
quality
monitor
indicates
signal
deterioration, the user may manually initiate a fallback io
transmission speed.
Parameter Protect
The front panel parameter protect switch protects current
configuration of parameters from being changed either by
command or down-line loading. This prevents either accidental
or deliberate tampering with system parameters from a remote
location once the system is set up.
Simple Programming Dialog
Interactive commands make supervisory functions easy. DFM
command structure includes prompting that helps first-time
users through each step of a complete command.
Experienced
users can use abbreviated commands to speed the process.
Nonvolatile Storage
DFM option settings are stored in NVROM (nonvolatile read only
memory), which is not disturbed by loss of power. Thus, units
do not have to be reprogrammed if a power interruption occurs.
Password Secured Access
Passwords assigned and changed only by the system manager
limit the use of supervisory and data channel command modes to
authorized users only. There are two levels of password
access: user and system manager.
The USER level allows access to noncritical functions such as
monitoring
status,
displaying
configuration
parameters,
executing limited test functions, and normal data channel
usage via the CONNECT/DISCONNECT commands. The SYSTEM MANAGER
level allows access to all command functions.
Autodisconnect
Switched channel connections can be automatically disconnected
if there has been no data activity within a timeout period
defined by the system manager.
Releasing inactive computer
ports pe rmi ts ex i st i ng ha rdware
fac il i ties
to
be more
efficiently allocated.

1-6

1.2.3 Intelligent Interfacing
Channels may operate synchronously or asynchronously using 5-, 6-,
7-, or a-bit data with even, odd, or no parity, and anyone of
thirteen flow control conventions. In addition, the DFM unit
provides the following for each channel:
Speed Conversion
Channel ends may be programmed for different speeds allowing
terminal devices to communicate with one another, regardless
of differences in speed.
This is especially convenient in
applications using switched channels.
Flow Control Conversion
Flow control conventions are separately programmed for each
channel end. The intelligent interface provided by the DFM
unit automatically translates flow control types between ends.
Incompatible devices now can be connected by taking advantage
of this feature. For example, a computer using XON-XOFF flow
control can be connected to a printer that uses DSR-DTR, and
the DFM system ensures that data is stopped and started as
required by either device.
Autobaud
Autobaud automatically adjusts the multiplexer data rate to
match the speed of the connected terminal.
It does this by
determining the speed of the first character received
(expected to be a RETURN). This feature is a necessity when
DFM channels are connected to dial-up modems since the
transmit speed of the terminal may be an uncertainty. Autobaud
also may be used on channels directly connected to terminals.
Break Character Control
Break characters are accepted by the DFM unit and reproduced
at the other channel end.
Accuracy is crucial because some
data terminals have functions associated with break characters
of different lengths.
Flyback (Fill) Character Delay
A specified number of NUL characters is transmitted following
a RETURN on DFM channels. Some terminal devices (especially
printers) require additional time for the print head or cursor
to return to the starting point for the next line of data. Use
of this feature prevents loss of data.

1-7

1.2.4 Comprehensive Diagnostics
Pinpointing failures is made easy by the automatic self-tests and
diagnostic tests available to data channel operators or the system
manager.
Power-up Self-test
Built-in self-test diagnostics are executed when the units are
powered on or restarted from the supervisory channel. They
detect most hardware failures.
LED error codes identify the
failure and location.
System Manager Level Tests
Diagnostic test capabilities including Channel Loopback, Link
Loopback, Remote Echo, Local Echo, and Pattern tests are
available to the system manager. Tests are executed from
either the supervisory channel or any properly enabled data
channel.
Data Channel Level Tests
Data channel command mode allows a limited subset of tests to
be run without having to enter a password. Local Echo, Remote
Echo, Channel Loopback, and Pattern tests may be run on any
channel that is in command mode.
Manual Maintenance Mode
When the supervisory channel is inoperative or not available,
a subset of testing features may still be run by using the two
maintenance pushbuttons (Ml and M2) on the control module.
Front panel LEDs indicate test results.
1.2.5

Expansion Capability

Modular Design
Simplicity of design enables tool-free access and module
change by quick removal and reinsertion into the backplane.
Failures are quickly isolated to a replaceable module. All
LEDs and pushbutton swi tches are readily accessible on the
front panel.
Expansion Line Modules
Channel capacity can be increased in A-channel increments, up
to a maximum of 16 channels.
Of each 4-channel group, two
channels can support synchronous or DDCMP operation.

1-8

Integral Modem Module
For complete system independence and single-source support,
Digital Equipment Corporation provides several integral modem
modules available in 2400 bits/s, 4800 bits/s, or 9600 bits/s.
Modem control, testing, and moni toring are made easy by the
use of front panel switches and LEDs.
1.2.6 Maximized Throughput
DFM design and functions optimize both response time and link
utilization (throughput):
Multi-microprocessor Design
The DFM uni t has up to four microprocessors that perform a
variety of independent processing tasks.
The control module,
channel modules, and integral modem module have their own
microprocessor(s). This distributes the workload and optimizes
microprocessor
time,
which
maximizes
throughput
and
performance.
Internal Direct Memory Access (OMA) Data Transfer
Control board log ic transfers data directly between channel
and link, relieving the processor of this task.
This
increases
overall
processing
capability
and
provides
exceptional throughput and response time.
Channel Input and Output Buffers
Each DFM channel has input and output buffers.
Each buffer
has a capaci ty of 4K bytes for synchronous channels and 2K
bytes for asynchronous and swi tched channels. Separation of
buffering, aids link throughput and minimizes the possibility
of buffer overflow.
Error Correction
The DFM system provides automatic correction of errors that
occur during data transmission.
A cyclic redundancy check
(CRC) is run on each block of data as it is transmitted and
received. Any discrepancy results in an automatic request for
retransmission. The CRC method guarantees an undetected error
rate of about one in one trillion.

1-9

1.3 APPLICATIONS AND CONFIGURATIONS
The versatil i ty of the DFM uni ts enable them to support a large
variety of applications. Computers can be used at either or both
ends of the link, as well as any mix of printers, terminals,
personal computers, or moderns. Swi tching and contention features
pe rm i t a si ng 1 e un i t to be used as a local equi pmen t allocat ion
device. Configurations of the DFM system include support for:
•

Channel switching and port contention

•

Single-unit use of switching functions

•

Tail circuits
(either dial-up
connected to a remote DFM port)

•

Dial-up computer timesharing

•

Communications via satellite

•

Both asynchronous and synchronous traffic

•

Multiple DFM configurations

dedicated

modems

1.3.1 Switching and Contention
Channel switching and contention features provide the flexibility
required in the rapidly changing data communications environment.
Any switched channel end can be connected to any other, if allowed
by the security feature. This makes it possible for a user to have
immediate access to all authorized company facilities (see Figure
1-3) •

The channel contention feature allows a unit at one end of the
network to be connected to a unit with fewer channels at the other
end. Terminals at one end contend for connections on a first
corne, first served basis. Inactivity for a time period selected by
the system manager results in an automatic disconnect, freeing
unused computer facilities.
The contention feature allows a limited number of computer ports
or other facilities to be shared among a variety of users.
By
minimizing the need for additional computer ports, this feature
obtains maximum performance from existing hardware facilities.

1-11

COMPUTER

l -j _\

~~
~~

SUPERVISORY
COMMAN 0
CHANNEL (SCC)
PRINTER

TERMINAL TO COMPUTER SELECTION

_ _ _ COMPUTER TO COMPUTER SELECTION

_ _ _ _ LOCAL RESOURCE SELECTION

TERMINAL TO TERMINAL SELECTION

TERMINAL TO PRINTER SELECTION
TK-10650

Figure 1-3

Switching and Contention Configuration

1-12

There are circumstances in which a large number of users require
connection to a variety of in-plant facilities, or a limited
number of computer ports need to be shared locally by many users.
In such an application, a single unit may be used as a local
swi tch (see Fig ure 1-4).
By us i ng the simple CONNECT command,
users are either connected or queued for connection to the desired
facility.

TERMINAL

PERSONAL
COMPUTER
COMPUTER 1

COMPUTER 2

TERMINAL
PERSONAL
COMPUTER

PRINTER

MKV84·0285

Figure 1-4

Single-Unit Switching Functions

1-13

1.3.2 Tail Circuits
Figure 1-5 illustrates a network configuration with DFM sites in
Boston and Chicago, each having a substation (called a tail
circuit).
Each tail circuit connects to the DFM unit by modems
using either public switched telephone facilities or private
leased lines.
Notice in Figure 1-5 that each DFM site has a
variety of channel devices.

------,
TERMINAL

~~~Y_-_---1

------------.
I
I
I

I
COMPUTER

SUPERVISORY
COMMAND
CHANNEL (SCC)

SYNC
CHANNEL

L _____

Q
BOSTON, MA

________I

MKV~76

Figure 1-5

Distributed DFM Network with Dial-up Remotes
(Sheet 1 of 2)

1-14

I----~E:::_--,I

I
~." I
IL ____~~I
COMPUTER

MODEM

DET-R.2!.!:~-.J

9600 b/s

I
I

I
I
I

PERSONAL
COMPUTER

VT278

SYNC CHANNEL

CHICAGO, IL

L ____________~
TK·10649

Figure 1-5

Distributed DFM Network with Dial-up Remotes
(Sheet 2 of 2)

The number of tail circuits is limited only by the number of DFM
channels. The configuration in Figure 1-6 allows a business in one
city to provide computer time to customers in another. In this
type of application, all channels on the remote unit are connected
to dial-up modems, allowing customers to access the remotely
located computer by a local phone call.

1-15

IcHI~GO~ -

~,I'

l-=2 !

'IJ~I=;JD~

I COMPUTER
,

I~~

'-...;;;;::::.

I PERSONAL

I
I
,

:n~.

COMPUTER

.-,' "
(l

9600 bts

~~.

SUPERVISORY
COMMAND

\~~ CHANNEL (SCC)
TERMINAL
____ _

I
I

I
,
~

L_~

I
I

L _____ _

QUINCY

CHELSEA
DIAL-UP LOCAL MODEMS = ACCESS
TO LONG DISTANCE CPU
MKV84-Q286

Figure 1-6

Dial-up Computer Timesharing

1-16

1.3.3 Satellite Links
DFM network configurations are not limited to conventional
terrestrial link facilities.
Concentrated link facilities can
include microwave, fiber-optic, or satellite components.
Figure
1-7 illustrates the use of a satellite link instead of a telephone
line.

PERSONAL
COMPUTER

COMPUTER

EARTH
STATION

'-----IT]

TERMINAL

rrT-l.

~
PERSONAL
COMPUTER

SATELLITE
EARTH
STATION
COMPUTER
TK·10652

Figure 1-7

DFM System Using Satellite Link

1-17

1.3.4 Synchronous Channels
The DFM uni t handles synchronous data traffic on up to one-half
its channels. Each of these channels can be configured separately
to support various data speeds and block sizes.
All synchronous
data channels that use EIA flow control have data statistically
multiplexed to provide maximum throughput. In addition, special.
control for Digital Equipment Corporation's DDCMP protocol is
provided by monitoring the incoming data for control, maintenance,
and
data
messages.
When
detected,
messages
are
relayed
immediately.
See
Figure
1-8
for
synchronous
channel
configurations.

VT278 SYNC

SYNC

1-------.... ASYNC

ASYNC ~_-.J

COMPUTER

~l
-

_
~.

SUPERVISORY
COMMAND
CHANNEL (SCC)

~
PERSONAL
COMPUTER

PERSONAL
COMPUTER
TK.108S7

Figure 1-8

Synchronous Channel Configuration

1.3.5 Multiple DFM Configuration
By taking advantage of synchronous channel capability, two pairs
of DFM units can service a multiple DFM application (see Figure
1-9). In this configuration, channels from two separate locations
use the same concentrated link. This configuration is particularly
economical when one site is significantly farther away from the
other two (for example; sites in Boston, New York, and Denver).
Again, a channel at any of the sites may also be dialed into or
connected to dedicated modems.

1-18

IDENVER -

IBOSTON - - - ~~E;;NA;l
I TERMINAL ~ ~""'9"" COMPUTER I
I
.'-I

-- -

:[][IJ------I
I COMPUTER

---, :
I
I

~~~~

TERMINAL

~l :

I
I-I
-\
I
I
SUPERVISORY CL \~1.
COMMAND
~-.
I rp"E;SO-;;-L ~
L ____C~NEL (SCC) _ _ ---.J
I COMPUTER , -

__ J
-

--1
I
I

TERMINAL

I
I
PERSONAL
COMPUTER

~
'(~
TERMINAL

L ____________
_
NEW YORK

I
I

MKV84-0287

Figure 1-9

Multiple DFM

CHAPTER 2
PREINSTALLATION PLANNING

2.1 GENERAL
This chapter provides guideline information for planning DFM
installations. This information is to help determine what
additional equipment will be required to satisfy your application
requirements. The latter portion of the chapter provides crossreference data for determining placement of the uni ts, cabl ing,
and other requirements.
2.2 SUPERVISORY CHANNEL
Use of the independent supervisory command channel (SCC) is
required during initial installation to set up the system
parameters, which are described in Chapter 6. Once the system is
set up, the terminal may be moved to a data channel where it may
alternatively be used for supervisory purposes. In most cases,
once the system is set up, there is little need for supervisory
access.
The SCC terminal should be located within 15.24 m (50 ft) of the
DFM unit for a direct connection.
For distances greater than
15.24 m (50 ft), line drivers, modems, or a dial-up connection may
be used.
Terminals connected to the supervisory port must be asynchronous,
and set to some combination of the following:
•
•
•
•
•

Seven or eight bits
Parity of even, odd, or none
One stopbit
Flow control of either XON-XOFF or none
Speed of 150, 300, 600, 1200, 2400, 4800, or 9600 bits/s

The supervisory channel is equipped wi th an autobaud mechanism
that allows it to adjust to the current speed setting of a
terminal when it is connected. Autobaud can detect speeds of 150,
300, 600, 1200, 2400, 4800, or 9600 bits/s.
Setting up the system is done via interactive commands: commands
that the system prompts for, and responds to in English.
After
initial programming, other supervisory functions may be done from
either the supervisory channel or from data channels. Both provide
password protected ability to set parameters, monitor data flow,
and test the DFM system. Except for setting a few link and system
parameters, all input may be made at one end of the system.

2-1

There are three levels of system control:

2.3

•

Supervisory Level -- This level is the highest level of
system control and requires a password.
The supervisory
level password allows the system manager total supe rv isory capability. This level displays a SYS> prompt.

•

User Level -- This level also requires a password, but is
more restrictive, not allowing parameter changes or test
functions. This level displays a USR> prompt.

•

Channel Operator Level -- This level allows channel users
to perform tasks necessary for their channels only,
without a password. This level is available only to
channels that have been enabled via the supervisory
level. This level displays a SEL> prompt.
CHANNEL CONSIDERATIONS

2.3.1 Channel Type
Channel type parameter allows the DFM unit to support the
communications protocol of devices connected to the selected
channel. Choices are:

•
•
•
•
•

Asynchronous,
Switched,
DDCMP,
Synchronous, and
Unused.

2.3.1.1 Asynchronous Channels
Asynchronous channel types
operate with asynchronous protocol, and are dedicated.
For
example, a dev ice connected to Channel 1 on the local uni t can
only communicate with whatever device is connected to Channell on
the remote unit.
2.3.1.2 Switched Channels -- Switched channel types operate with
asynchronous protocol, but can be connected to any other switched
channel via the CONNECT command (see Chapter 5).
Switched
channels are completely independent; Channell on the local unit
may be connected to any other switched channel on the local unit
as well as any switched channel on the remote unit (see Channel ID
and Group Access Options, Chapter 6).
The switched channel "contention" feature allows a limited number
of computer ports or other hardware facilities to be shared among
a variety of users. This enables, for example, a 16-thannel unit
to be connected to a unit with fewer ports. Channel contention
operates on a first come, first served basis. Suppose that Channel
1 on the local unit requests connection to Channel 3 on the remote
unit. If Channel 3 on the remote unit is already connected to
another switched channel, the request is queued.

2-2

If Channell's request is the first one queued, it will be
connected as soon as Channel 3's current connection is terminated.
Otherwise, it must wai t until prior requests for connection are
satisfied. Channels requesting connection to busy channels or
groups remain queued until either a connection is made, or the
request is withdrawn with the DISCONNECT command.
2.3.1.3 Synchronous Channels -- Synchronous channels are defined
as either DDCMP or sync channel types. DDCMP is Digital Equipment
Corporation's proprietary protocol used primarily with systems
joined by DECnet facilities. Synchronous channel types support any
type of synchronous communications protocol in a transparent
manner (that is, the DFM unit does not look at or interpret data
on the channel). Because of internal buffering, however, some
delay in the data transfer may be experienced.
Since constant commun icat ion between dev ices is a pa rt of most
synchronous protocols, synchronous channels have a big impact on
link utilization. Data rate calculations for the link must include
120% of the combined data rates for full-duplex syn9hronous
channels.
For DDCMP and half-duplex synchronous operation, the
link calculations must include 50% of aggregate input.
Half-duplex operation is recommended whenever possible for
Half-duplex operation is
synchronous (non-DDCMP) channel types.
selected by CTS-RTS flow control.
DFM handl ing of the DDCMP protocol el iminates the need for flow
control or half-duplex operation. In DDCMP protocol, when the DFM
unit detects an "idle" frame (no data present), it does not
transmit it.
This saves concentrated link bandwidth for frames
with data.
Synchronous channel loading must be spread evenly among channel
modules. For this reason, the DFM unit only supports synchronous
or DDCMP operation on two out of every group of four channels
(Channels 1 and 2, 5 and 6, 9 and 10, and 13 and 14). The load
should be spread as evenly as possible. For example, if 3
synchronous channels are required on a l2-channel unit, they
should be assigned to Channels 1, 5, and 9.
Since synchronous communications protocols typically include their
own error detection and retransmission schemes, the DFM unit does
not provide error correction on synchronous and DDCMP channel
types.
Section
2.4.2
covers
link
speed
synchronous channel considerations.

2-3

calculations,

including

2.3.1.4 Unused Channels -- Channels not currently in use may be
set to a channel type of unused. This prevents the channel from
being serviced by the DFM unit, reduces system overhead, and
improves service to the remaining channels. Channels may be
changed from one of the other types to unused and then back,
without losing parameter settings.
2.3.2 Connecting a DFM Channel to a Modem
Either dial-up or dedicated modems may be connected to a DFM
channel. For 12~~ bits/s dial-up capability, the 212A compatible
DFl12 modem is available. For 24~~ bits/s operation, the DF124 or
DF224 modems are available.
A crossover cable (BC22M cable or equivalent) must be used to
connect a modem to a DFM channel.
When a dial-up modem is used,
it is possible to have the host computer or the DFM uni t manage
the
handshaking
sequence.
(See
Section
6.7.2
for
more
info rmat ion.)
Synchronous and DDCMP channels can be dialed into only if a modem
with an auto-answer feature is used; carrier detect (CD), data
terminal ready (DTR), and clear to send (CTS) are always asserted
on synchronous and DDCMP channels.
2.3.3 Channel Cabling
Regardless of the channel type setting, straight-through cables
are used for connection directly to terminals, and crossover
cables are required when a DFM channel is connected to a modem.
Further information on DFM cables is found in Table 2-1.
Cable
wiring diagrams are found in Appendix C.
2.4 LINK CONSIDERATIONS
The first consideration for the link is to determine what type of
facility will be used. The following sections discuss link types,
then suggest a procedure for determining link speed. Having
determined the required data rate for the link, it is possible to
determine requirements for direct or modem connections.
This, in
turn, establishes cabling requirements.
2.4.1 Type of Link
A communications link can be anyone of the following:
•

Dial-up phone line with modems;

•

A leased (or dedicated) line with modems;

•

Microwave or satellite transmission service
accessed through phone connections); or

•

Direct, short-haul connection via line drivers or fiberoptic media.

2-4

,(typically

With dial-up phone lines, data is sent through the telephone
company's regular voice grade I ines and intermediate swi tching
circuits.
At times, noise and interruptions on these lines can
make effective data communications difficult, if not impossible.
Leased lines are physically separate circuits that are not shared
with other users. A leased line is available at all times and can
achieve high-speed transmission in both directions simultaneously
by employing a 4-wire circuit.
In addition, the monthly charge
for leased lines does not vary with hours of usage as it does with
dial-up lines. Under some circumstances, however, even dedicated
leased lines experience noise interruptions and line -hits,- which
may lead to garbled data transmissions.
Two other forms of transmission media are becoming increasingly
popular:
•
•

Microwave, and
Satellite.

Both provide high-speed, high-volume data communication. Microwave
links are particularly effective for intracity applications,
satellite
links
offer
effective
overseas
and
intercity
connections.
When data communications capabilities are needed for more than a
few hours each business day, a dedicated phone line is usually the
most economical solution, even for one terminal.
If there are
several terminals in use at the same time and location, the user
will need a dedicated line to take advantage of the cost savings
of multiplexing with the DFM unit.
All cables used as part of the concentrated link should be of ~igh
quality
construction,
preferably
shielded
twisted
palrs.
Specifications for cables used as part of the concentrated link
are described in Appendix C. The characteristics of the signals on
the concentrated link as well as channel lines are covered in
Appendix E.
2.4.2 Data Rate for the Link
The proper data rate (speed) of the concentrated link in any
application
is
an
important
factor
in
achieving
optimum
performance from the DFM system. The speed must be great enough to
handle the anticipated data traffic, but no greater than that
because of the increased cost of higher speed communications
facilities.

2-5

Link speed is determined by:
1.

Dividing channel devices into categories
a.
b.
c.
d.
e.
f.

Estimating
category
a.
b.
c.
d.
e.
f.

Asynchronous CRTs with flow control
Asynchronous CRTs without flow control
Asynchronous block mode CRTs
Printers
DDCMP or half-duplex synchronous devices
Full-duplex synchronous devices
a

"required

bandwidth

Async with flow control
Async without flow control
Async block mode CRTs
Printers
DDCMP, half-duplex sync
Full-duplex synch

factor"

for

each

= .15
= .25
= .30

= .35 to .6
= • 50
= 1.2

Multiplying the combined baud rates of each category
times the required bandwidth factor
For example, suppose there are four asynchronous
(using flow control) operating at 4800 bits/s:

CRTs

Combined baud rates = 4800 X 4 = 19,200 bits/s
19,200 X .15 = 2880 bits/s
Thus, 2880 bits/s of link speed is required for these
devices. Suppose there are also two DDCMP channels
operating at 2400 bits/s:
Combined baud rates = 2400 X 2 = 4800 bits/s
4800 X .5 = 2400 bits/s
2400 bits/s of link speed is required for
devices.

these two

Final link speed is calculated by adding the totals for
each category. In this example, 2880 bits/s + 2400
bits/s, or at least 5280 bits/s of link speed are needed.

2-6

The bandwidth factors listed are estimates only, based on average
conditions and usage. Additional factors may require that these
estimates be revised either upward or downward.
For example, if
an asynchronous terminal using flow control is planned for a very
light usage application (one or two hours a day) the required
bandwidth factor for that device may be lowered to .1B.
On the other hand, if the same terminal is to have an unusually
heavy application, it is advisable to increase the bandwidth
factor to .20.
In general, bandwidth factors should not vary much from the
preceding figures. In the case of printers, however, the amount of
usage can significantly alter the estimate given.
When a printer receives data at full capacity, it will tend to
monopolize the link for the duration of the job. Thus, if a
printer will be running for more than 10 or 15 minutes each hour,
a factor of .6 (or greater) may be warranted. If it is going to be
running only a few minutes each hour, a factor of .35 to .4
probably will be sufficient.
For asynchronous block mode terminals, the factor to be used is
dependent on the size of the block, even when flow control is in
use. This is because the CPU usually will not respond to flow
control except between blocks of data. If the size of the blocks
is not too big (for example, fewer than IB00 bytes), the suggested
factor of .30 should be adequate. Otherwise, like a printer,
terminals will monopolize the link for the duration of the block,
and the factor required should be increased proportionately.
Flow control usually increases the response time to remote
devices. Since the DFM units regulate the flow of data, however,
data will not be lost. Without flow control, as the speed of the
concentrated link is reduced, the chance of buffer overflow and
subsequent loss of data is increased.
When an error is detected, the DFM unit automatically retransmits
data. Thus, a higher error rate directly reduces the effective
throughput of the concentrated link. If phone lines are known to
be troublesome, the estimated link speed should be increased
accordingly. In general, the larger the network, the more
conservative the estimate of link speed should be.
Once an estimate of required link speed is reached, the result is
adjusted upward to achieve a faster response, assure a better echo
of data, or to anticipate a high error rate.

2-7

LINK MODEMS
The DFM unit can operate with either a variety of standalone
external modems such as the DFl00 series or a variety of optional
integral modem modules.
2.5

2.5.1 Optional Integral Modem
The DFM enclosure supports an optional integral modem module of
either 9699, 4809, or 2499 bits/s, allowing complete system
independence and single-source support of the DFM system.

While the DFM unit can work in conjunction with nearly any type of
modem, the DFM integral modem is the ideal match. The integral
modem is a self-equalizing, synchronous modem designed for pointto-point applications. Self-equalization allows them to adjust
automatically to changing line conditions, which means that they
operate effectively over standard, unconditioned voice grade lines
(type 3992).
External Link Modems or Line Drivers
If external modems are used, they must meet two primary criteria:

2.5.2

•

They must handle control signals in a way that allows the
DFM uni ts to detect an interruption to communications
(for example, by dropping CTS).

•

They must be data transparent; that is, they must not be
dependent
on
the
communications
traffic
being
in
character format.

The DFM unit can operate with synchronous moderns of any speed up
to 19.2K bits/s. The only asynchronous link speed that is
supported, however, is 9600 bits/s. Currently, the only type of
asynchronous modern that is as fast as 9600 bits/s is a short haul
modem.
If DFM units are to be a maximum of 15 to 20 miles apart, it may
be possible to utilize short haul, asynchronous moderns operating
at 9690 bi ts/s. Check manufacturer's requi rements for distance,
and other requirements such as conditioning of the telephone line.
For interplant applications, the DFM units may be either directly
connected, or connected with line drivers.
Digital Equipment
Corporation recommends a maximum of 15.24 m (50 ft), in accordance
with EIA standards, for units to be directly connected. With high
quality cable and the absence of any electrical interference, it
may be possible to go farther than 15.24 m (50 ft).
Line dr i vers are used in conj unction wi th in-plant cables up to
approximately 1524 m (5000 ft). They amplify the input digital
signal so that longer distances can be covered without signal
deterioration. Check manufacturer's requirements for distances and
types of cables required.

2-8

Table 2-1 summarizes cable types and usage in conjunction with the
various kinds of communication facilities.
2.6 OPERATING CONDITIONS FOR THE DFM UNIT
The DFM unit is designed to operate in a clean and dry environment
such as a computer room or office area. It is lightweight and can
be placed on any solid, unheated surface such as a shelf br
desktop. Do not place the unit on top of a cabinet that generates
heat. The DFM unit may also be located in the H9646 communications
cabinet on an optional louvered shelf. Clearance on the sides of
the unit is not important. Avoiding obstruction of the bottom and
top ventilation holes, however, is very important.
CAUTION
Do not block top or bottom ventilation
holes. Convection is the only method of
cooling the unit. If ventilation is
restricted, damage will result.
About 10.16 cm (4 inches) of clearance at the rear is required for
cable connection and routing. The front of the unit should be in a
position that makes the front panel LED indicators clearly
visible.
2.6.1 Environment
0
TheoDFM unitooperates within temperatures ranging from 0 to 40 0 C
(32
to 104 F) and relative humidity ranging from 0% to 95%
noncondensing up to an altitude of 2438
m (8000
ft). Storage
o
(nonoperating) temperatures are from -35 0 to 7l C (-30° to l60 0 F).
2.6.2 Power Requirements
Nominal power required for the DFM unit is 115 Vac (230 Vac
optional) within the 50 to 60 Hz frequency range at 92 W. The DFM
uni t
is Underwri ter' s Laboratory (UL)
listed and Canadian
Standards Association (CSA) approved. The power cord is 2.1 m (7
ft) long.
2.7 PREINSTALLATION TEST AND FAMILIARIZATION
A pre installat ion benchtest (Chapter 3) is recommended for each
pair of DFM units prior to installation at local and remote sites.
The purpose is both to ensure that the units are functioning
properly, and to familiarize operators with their use.
For this
reason, it is strongly recommended that both DFM units be sent to
the same site.
When integ ral modems are purchased, uni ts are connected for the
test with a piece of phone wire or any other compatible 4-wire
cable.
If integ ral modems are not purchased, Dig i tal Equipment
Corporation recommends purchasing a BC22L cable, or obtaining
another cable that conforms to null modem specifications in
Appendix C. The BC22L cable crosses receive and transmit pins and
loops back other signals so that DFM units can communicate without
modems between them.

2-9

2.8 DFM CABLES
Figure 2-1 shows the locations of the various cables required with
the DFM system. Table 2-1 provides cable descriptions and order
numbers.
Each channel presents a DCE interface which can be directly
connected to a terminal (DTE), in which case, a straight-through.
cable is used.
If a channel is connected to a modem (DCE), a
crossover cable must be used.
The link (connector J18) presents a DTE interface, expecting to be
connected to a modem (DCE). If units are to be directly connected
(DTE to DTE), a crossover cable must be used.

ASYNCHRONOUS OR
SWITCHED
CABLE E
CHANNEL
DEVICE

CHANNEL 1
CHANNEL 2
CHANNEL 3
CHANNEL 4
CHANNEL 5
CHANNEL 6

SYNCHRONOUS OR
DDCMP
CABLE F
CHANNEL
DEVICE

CHANNEL 7
CHANNEL 8
CHANNEL 9

El
El
~
~

E1
0
EJ
0

~
~
CHANNEL 11
~
CHANNEL 10

PRINTER
DEVICE

CABLE E

DIAL-UP TAIL
CIRCUIT CONNECTS
TO CHANNEL 16
DEVICE VIA MODEM

..si1

MODEM

CHANNEL 12

CHANNEL 13

CHANNEL 14

CHANNEL 15
CABLE M

CHANNEL 16

SUPERVISORY
COMMAND
CHANNEL (SCC)
CABLE E

USE CABLE F FOR EXTERNAL
MODEM LINK; FOR SYSTEM
PRETEST CONFIGURATION,
USE CABLE L

[!}--B ~ MODEM;tLUSE STANDARD 4-WIRE
TELEPHONE CABLE
FOR DFM
INTEGRAL MODEM
CONNECTIONS

E1
EJ

B
MKV85·2OQO

Figure 2-1

DFM Cable Connections

2-10

Table 2-1

Cable Descriptions and Order Numbers

Cable

Description

Order No.

Cable F

Straight-through cable with male to
female connectors for connection of
synchronous DTE to DFM channel, or the
connection of a modem to the link or the
link connection of one DFM unit to the
channel connection of another DFM unit.

BC22F-XX

Cable E

Straight-through cable with male to
female connectors for connection of
asynchronous DTE to the DFM unit.

BC22E-XX

Cable M

Crossover cable with male to male
connectors for connection of DCE to
DCE (modem to DFM channel), or for the
route-through applications in which
channels of two DFM units are connected
together.

BC22M-XX

Cable L

Null modem cable with female to female
connectors. Recommended for preinstallation
test with units having no integral modems.

BC22L-XX

Cable T

Special loopback test cable.

See
Appendix C

NOTE
The XX suffix on order numbers indicates
the length of cable
(for example,
BC22L-10 is a 10 ft null modem cable).

2-11

2.9 PREINSTALLATION EQUIPMENT SELECTION
An inventory of current and planned equipment to be supported by
the DFM unit is important for proper selection of DFM units,
cables, and accessories.
Figure 2-2 is a guide for planning a DFM installation. It covers
selection of the proper size DFM units, cables, and other
communication facilities. Make copies of the guide for use as
worksheets. Examples that illustrate its use are provided in the
following sections.

REMOTE

LOCAL
TERM
DEV

CABLE

MODEM

PHONE
LINE

MODEM

CABLE

DFM
CHANN

CABLE

MODEM

PHONE
LINE

MODEM

CABLE

TERM
DEV

MODEM

PHONE
LINE

MODEM

CABLE

TERM
DEV

MODEM

CABLE

DFM
DEV

SUPERVISORY CHANNEL EQUIPMENT
TERM
DEV

CABLE

MODEM

PHONE
LINE

MODEM

CABLE

DFM
CHANN

CABLE

LINK EQUIPMENT
DFM
DEV

CABLE

MODEM

LINK PHONE LINE

MK V8&-200 1

Figure 2-2

Hardware Selection Guide

2-12

2.9.1 Using the Hardware Selection Guide
The following examples illustrate how the hardware selection guide
may be used to determine additional hardware required for DFM data
channels, the supervisory channel, and the concentrated link.
Example 2-1: Channel Connections -- Refer to Figure 2-3 for a
sample of how to fill in the hardware selection guide for the
following configurations.
Channel 1 is connected to the host computer at the local end. The
remote channel end is connected to a VT100 through a dial-up
modem. A 7.6 m (25 ft) cable is required at the local end. At the
remote end, a 3.0 m (10 ft) crossover cable is required between
the DFM unit and its 2l2A modem. A phone line connects the remote
DFM unit's 2l2A modem to a dial-up 2l2A modem, which is attached
to a VT100 terminal via a 3.0 m (10 ft) straight-through cable.
Channel 2 connects a synchronous terminal to the host computer via
crossover cables at both DFM units.
NOTE
Synchronous and DDCMP devices can be
operated only on Channels 1, 2, 5, 6, 9,
10, 13, and 14. This ensures that
synchronous
channel
load
is
spread
evenly among four channel groups.
Local channels 4, 5, and 8, and remote channels 3, 4, 5, 6, and 7
are swi tched (asynchronous) channels.
All are connected to the
DFM unit by straight-through cables.
Local channels 6 and 7, and remote channel 8 are unused.
REMOTE

LOCAL
TERM
DEV

CABLE

MODEM PHONE
LINE

MODEM

..,
.....
..
-.,

VAX
VAX

CABLE

DFM
CHANN

CABLE

MODEM

PHONE
LINE

MODEM

CABLE

TERM
DEV

E·25

M·l0

212A

DIALUP

212A

E·l0

VT100

F·25

E·25

UNUSED

E·25

UNUSED

E·25

:
:

VAX

E·25

.-. E·25
.... E·25

VAX
VAX

... E·25

VT100
:
:

-....

SYNC
TERM .

VTl02

--..
..
..
..-

VT102
VTl02

VT100
VT202
UNUSED

:
:

MKV85·2002

Figure 2-3

Hardware Selection Guide for Example 2-1

2-13

Example 2-2: Supervisory Command Channel (SCC) Connections -Refer to Figure 2-4 for a sample of how to fill in the hardware
selection guide for the following configuration. The local SCC is
to be directly connected to the DFM unit via a 7.6 m (25 ft)
stra ight-through cabl e. The remote SCC is shown connected v ia a
3.0 m (10 ft) crossover cable to a dial-up modem, allowing the
system to be managed from a remote location. A VT292 terminal is
connected to a modem at the other end of the phone link via a 7.6
m (25 ft) straight-through cable. Care must be taken to ensure
that proper modem control signals (such as DTR) are asserted for
the remote SCC.
LOCAL

TERM
DEV

CABLE

MOOEM

PHONE
LINE

VT202

REMOTE

MOOEM

CABLE

• E·25

OFM

DFM
CHANN

CABLE

CHANN
SUPV

SUPV

M·1O

MODEM PHONE
LINE
2l2A

MODEM

CABLE

TERM
DEV

212A

E·25

VT202

LEASED

MKV85·2003

Figure 2-4

Hardware Selection Guide for Example 2-2

Example 2-3: Direct Link Connections (No Modems) -- Refer to
Figure 2-5 for a sample of how to fill in the hardware selection
guide for the following configuration. This example illustrates a
direct connection using a null modem cable. The AA suffix on the
DFM serial numbers indicates that there are no integral modems
installed. The 08 code indicates that the DFM unit has 8-channel
capability. The null modem cable is connected to connector Jl8 on
the DFM units.

DFM
DEV

LINK PHONE LINE

DFM
DEV

- - - - - - - - - - - - - - - -•• 08·AA

MKV85-2004

Figure 2-5

Hardware Selection Guide for Example 2-3

2-14

Example 2-4: Link Connections wi th Integral Modems -- Refer to
Figure 2-6 for a sample of how to fill in the hardware selection
guide for the following configuration.
This configuration uses
integral modems installed with a data rate of 9689 bits/s as
indicated by the AC suffix on the DFM model number. The units have
12-channel capability. A dedicated phone line is used for the link
and attached directly to the J19 connector on both units.

DFM
DEV

LINK

12·AC ••-----DEDICATED PHONE L l N E - - - - -•• 12·AC
MKV8S-2005

Figure 2-6

Hardware Selection Guide for Example 2-4

Example 2-5: Link Connections wi th External Modems -- Refer to
Figure 2-7 for a sample of how to fill in the hardware selection
guide for the following configuration. This configuration uses a
16-channel unit with no integral modems, as indicated by the
DFM-16-AA model number. The external modems are attached to the
DFM units with 7.6 m (25 ft) straight-through cables. The modems
are linked by a dedicated phone line.

DFM
DEV

CABLE

MODEM

16·AA

F·25

209A

LINK

~DEDICATED ---..

PHONE LINE

MODEM

CABLE

DFM
DEV

209A

F·25

08·AA

MKV85-2006

Figure 2-7

Hardware Selection Guide for Example 2-5

2-15

2.9.2 Determining DFM Size
Asynchronous devices may be connected to any channel. Synchronous
channel operation must be distributed among 4-channel groups. Only
Channels 1-2, 5-6, 9-10, and 13-14 can support synchronous
operation.
If your system must support three synchronous
channels, therefore, at least an 8-channel unit is needed. For
five synchronous channels, at least a 12-channel unit is needed
(see Figure 2-8).

DFM16·AC
DFM12·AC
DFM08·AC
DFM04·AC
CHANNEL NUM8ERS
SYNCHRONOUS/DDCMP ONLY

1 234

5 6 7 8

9 10 11 12

13 14 15 16

S S

DFM(XX) 1£ THE MODEL NUM8ER. XX = NUMBER OF CHANNELS IN THE UNIT.
THE SUFFIX CONTAINING TWO ALPHABETIC CHARACTERS AFTER THE DFM SIZE MEANS:
AA = NO MODEMS
AB = INTEGRAL MODEM V.27 4800 BITS/S
AC = INTEGRAL MODEM V.29 9600 BITS/S

MKV85-2007

Figure 2-8

DFM Sizing Aid

2-16

2.le INVENTORY AND REQUIREMENTS FORM
With the information presented so far, the Inventory and
Requirements Form of Figure 2-9 can be used to help in making
final requisitions.

REOUIRED
ITEMS

OTY
AVAIL.

DESCRIPTION

DFM04-AA
DFM04-AB
DFM04-AC
DFM08-AA
DFM08-AB
DFM08-AC
DFM12-AA
DFM12-AB
DFM12-AC
DFM16-AA
DFM16-AB
DFM16-AC
TERMINALS
ASYNCHRONOUS
SWITCHED
PRINTERS
SYNCHRONOUS
PERS COMPUTER
OTHERS
CABLES
BC22E-l0
BC22E-25
BC22F-l0
BC22F·25
BC22L-05
BC22L·l0
BC22L·25
BC22M-l0
BC22M·25
4-WIRE LINE

OTY
ROD

ORDER
OTY

4-CHANNEL ICP WIO INTEGRAL MODEM
4-CHANNEL ICP INTEGRAL MODEM V.27
4-CHANNEL ICP INTEGRAL MODEM V.29
8-CHANNEL ICP WIO INTEGRAL MODEM
8-CHANNEL ICP INTEGRAL MODEM V.27
8-CHANNEL ICP INTEGRAL MODEM V.29
12-CHANNEL ICP WIO INTEGRAL MODEM
12-CHANNEL ICP INTEGRAL MODEM V.27
12-CHANNEL ICP INTEGRAL MODEM V.29
16-CHANNEL ICP WIO INTEGRAL MODEM
16-CHANNEL ICP INTEGRAL MODEM V.27
16-CHANNEL ICP INTEGRAL MODEM V.29

ASYNCHRONOUS DTE-TO-DCE STRAIGHT THROUGH
ASYNCHRONOUS DTE-TO-DCE STRAIGHT THROUGH
SYNCHRONOUS DTE-TO-DCE - SHIELDED
SYNCHRONOUS DTE-TO-DCE - SHIELDED
SPECIAL DIRECT LINK - SYSTEM PRETEST
SPECIAL DIRECT LINK - SYSTEM PRETEST
SPECIAL DIRECT LINK - SYSTEM PRETEST
SPECIAL DCE-TO-DCE CROSSOVER SHIELDED
SPECIAL DCE·TO-DCE CROSSOVER SHIELDED
TELEPHONE CABLE OR EOUIVALENT

COM. LINES
LEASED LINES
DIAL·UP LINES
LINE DRIVERS
MODEMS
SHORT HAUL
ASYNCHRONOUS
SYNCHRONOUS

MKV85-2008

Figure 2-9

Inventory and Requirements Form

2-17

CHAPTER 3
INSTALLATION

3.1 GENERAL
This chapter covers the unpacking and inspection, the descriptions
of the DFM modules controls and indicators, and the installation
process of the DFM system. Part of that process is a preinstallation benchtest, which is designed to verify that the units are
functioning properly and to familiarize operators with their use
prior to installation at local and remote sites.
3.2 UNPACKING AND INSPECTION
The DFM uni ts and the user manual are shipped in one container.
Cables are shipped separately. Since problems usually can be
isolated to one of the replaceable modules, the original
containers need not be saved.
CAUTION
Do not try to carry the unit by the
front bezel. Handle the DFM unit by the
main portion of the enclosure only. The
front bezel of the DFM enclosure is
secured only by magnetic latches.
Inspect the unit and cables for dents, broken pieces, damaged
connectors/pins, damaged wires, and so forth. Verify that the
correct system components were shipped by comparing them to the
packing list.
Any damage should be reported to the shipper and Digital Equipment
Corporation at once. Inform the original sales person by telephone
of any shortages in the shipment.
3.3 VISUAL INSPECTION
Fig ure 3-1 shows the front of the DFM uni t wi th the front bezel
both on and off. It also shows module placement and location of
the identification decal.
3.3.1 Removing the Bezel
The front bezel is held in place by four heavy duty, magnetic
latches (two on either side). To remove it, grasp it by the front
window area wi th one hand and hold the enclosure wi th the other
hand. The magnetic latches are quite strong, requiring a firm pull
on the bezel.
3.3.2 Checking the Identification Decal
The identification decal is located on the bottom right of the
unit (see Figure 3-1). It lists the serial and model numbers.

3-1

00000

000
000
00
00

OO~

0000
0000

00000
0000
OC>
0000

0000
000
000
000

00000
0000
000
000

o
INTEGRAL

SPARE - FOR
FUTURE USE

SLOT 5
4·0R 8·CHANNEL
EXPANDER MODULE
CONTROL
MODULE

SLOT 4 MUST CONTAIN AN 8CHANNEL MODULE BEFORE
EXPANDING TO SLOT 5

__a. .
MODEL DFMXX - yy
SER. NO

AAA NNNN

MKV8S·2009

Figure 3-1

DFM Enclosure, Module Placement, and ID Decal

3-2

The serial number has seven characters: the first three are
alphabetical and the last four are numerical (for example,
SCA1234). The serial number uniquely identifies each DFM unit.
The model number defines the number of channels and whether or not
a modem module is present:
Model Number Format
DFM-XX-YY
DFM = The series of the intelligent communications processor

xx =

The number of channels, where XX can be 04, 08, 12, or
16

YY = The type of modem, where:
AA = No integral modem installed
AS = V.27 bis/4800 bits/s integral modem
AC = V.29/9600 bits/s integral modem
3.3.3 Checking the Modules
Figure 3-1 shows the proper location of DFM modules. Verify that
the correct modules are installed.
Slot 1 -- Integral modem module.
It is the only module with six
pushbutton switches and eight LEOs. Refer to Appendix B
for information on the integral modem.
Slot 2 -- Spare. This slot should be empty because it is intended
for future use.
Slot 3 -- Control module.
It is the only module
pushbutton switches and eight LEOs.

with

four

Slot 4 -- Channel module. Either a 4-channel expansion module
(identified by LED labeling C1 through C4) or an
8-channel expansion module (identi fied by LED label ing
C1 through C8) must be located in this slot.
S lot 5 -- Chan n e 1 ex pa n s ion mod u1 e • Ei the r a 4 - c ha nn e 1 ex pa n s ion
module (identified by LED labeling Cl through C4) or an
8-channel expansion module (identified by LED labeling
C1 through C8) may be used in slot 5.
Slot 4 must
contain an 8-channel module before expanding to slot 5.
See Table 3-1 for slot/channel combinations.
Slot 6 -- Power supply module. It is identified by the perforated
screen mesh that surrounds all the· components on the
module.

3-3

Table 3-1

Slot/Channel Combinations
Front Bezel Indications

Module Size & Location
Slot 4

Group A

Slot 5

1
1
1

4
8

8
8

4
8

4
8
8
8

Group B

9
9

12
16

3.3.4 Rear Panel Connectors
Figure 3-2 illustrates the location, function, and identification
of each rear panel connector. These locations, are also marked on
the rear panel of the unit.
Power Connector
and Line Fuse

The power connector and line fuse (5 A 250 V) are
on the left-hand side of the unit. There is no
power switch. When the power cord is plugged
into the wall socket, power is applied to the
un it.
Subsequen tl y, if powe r is lost and then
restored, the unit is automatically back ON.

Connectors
JI-JIG

Data channel connectors. Group A corresponds to
the module located in slot 4, with Jl through J8
being Channels 1 through 8. Group B corresponds
to slot 5.
Connectors J9 through JIG are .for
Channels 9 through 16.

Connector J17

Supervisory command channel
(SCC)
connector.
Ini tial programming of the system must be done
from the supervisory channel. After data channels
are
enabled
to
enter
command
mode,
all
supervisory functions may be performed from a
data channel (if desired).

Connector JI8

Link connector used for either a BC22L null modem
cable (direct connection to the other DFM unit),
or connection to an external modem (which is then
connected to the telephone line).

Connector J19

Link connector used when the integral modem
module is installed.
It provides for direct
connection to the phone line.

3-4

00 000
00000
0000

000000
00000
0000
000

0000
0000
0000
00

0000000
00000
00000
00000
00

GROUP B

GROUP A

UMW,y,wb',l.wb) UiYIYNNMYlU J1

J 10

tiYHNNNilNWlD

a-.WIt.'?UJ2

J11 h,1""U,H"""rl

UWHNI'NlIH,i)) J3

y,,'!"'""'''''''
J12 f1
~_"I~
...nwl"tl').J

ut."'JD U' '. JJ

J13

SUPERVISORY
COMMAND
CHANNEL (SCC)
CONNECTOR J17(F)

,,'U,,','o'I, . J5

Q,mmlHmHI/lJJI_

J 1 5 U',WII,wtWW

J 16

D U\"Wb'lUlNtHQJ :

Ummmuu,w"D Q'mn,'b2nm,'p.,
PRIVATE
UNE
CONNECTOR J19

6
LINK

FUSE

CONNECTOR J18(M)

GROUP B CONNECTORS (F) = SECOND
4-0R 8- CHANNEL EXPANDER LINE

GROUP A CONNECTORS (F) = FIRST
4-0R 8- CHANNEL LINE MODULE IN

MODULE IN SLOT 5

SLOT 4

J9 = CHANNEL 9
J10 = CHANNEL 10
J11
CHANNEL 11
J12 = CHANNEL 12
J13 = CHANNEL 13
J14
CHANNEL 14
J15 = CHANNEL 15
J16 = CHANNEL 16

J1 = CHANNEL 1 }
J2 = CHANNEL 2
DFM04
J3 = CHANNEL 3
J4 = CHANNEL 4
J5 = CHANNEL 5
J6 = CHANNEL 6
J7 = CHANNEL 7
J8
CHANNEL 8

DFM16

DFM08

NOTE
1. SLOT 4 MUST CONTAIN AN
8-CHANNEL MODULE BEFORE
EXPANDING TO SLOT 5
2. M = MALE CONNECTORS
F = FEMALE CONNECTORS
MKV85·2010

Figure 3-2

DFM Rear Panel Connectors

3-5

3.4 CONTROLS AND INDICATORS
Front panel LEDs on all modules blink as the units run the
power-up self-test. The LED pattern corresponds to the individual
hardware tests that are being run. Depending on the size of the
units (number of channels), this test cycle can take up to 10 or
15 seconds.
When the power-up tests are complete, only DR, NR, and CD should
be ON. If the link is not up (connected and ready), CD and/or NR
may not be ON. Chapter 7 describes the power-up test sequence in
detail.
3.4.1 Control Module
Control module pushbutton positions and functions are described in
Table 3-2. Control module LED indicator functions are described in
Table 3-3. Figure 3-3 shows the location of these pushbuttons and
indicators.
3.4.2 Channel Expansion Module
The channel expansion module does not contain any pushbutton
swi tches.
LED ind icators are descr ibed in Table 3-4 and Figure
3-4 shows their locations.
3.4.3 Integral Modem Module
The front panel of Dig i tal Equipment Corporation' slink modems
contain eight LED indicators and six pushbutton switches. The LEDs
display activity status, operating mode, or error conditions in
the modem.
Front panel swi tches are used to ini tiate tests and
control speed.
See Figure 3-5 for locations of modem module
controls and indicators.
Functions of front panel switches and indicators are different,
depending on the type of link modem being used.
Table 3-5 lists
the functions of front panel swi tches and LEDs, and identi fies
which ones are available on which modems.
Tables 3-6 and 3-7
describe all switches and indicators.

3-6

Table 3-2

Control Module Pushbutton Controls

Pushbutton Switch

Description

Maintenance 1 (Ml)
Maintenance 2 (M2)

These switches are used for manual maintenance purposes when there is no supervisory
terminal attached to the DFM uni t or the
supervisory channel is inoperative.

Test Function

OUT

Normal operations

OUT

Configuration option is forced to invalid.
(Chapter 6 describes configuration option.)
With only M2 IN, the unit's operating
parameters are down-l ine loaded from the
other unit when the unit is reset or
reinitialized.

OUT

Continuous sel f-test. When onl y Ml is IN,
pressing the system reset (SR) swi tch or
applying unit power causes the DFM unit to
continually repeat self-test. Only these
two methods
can
start
a
continuously
looping self-test. Chapter 7 details unit
sel f-tests,
system
reset,
and
reinitialization procedures.

Link loopback. When both swi tches are IN,
the LBACK test for the link is initiated.
Chapter 7 describes LBACK testing.
When the unit is in manual LBACK mode, both
the SD and RD LEDs should be ON, indicating
that the unit is continuously sending and
receiving data. Errors are indicated by
blinking SA and RA LEDs.
The supervisory channel cannot be used on a
unit
when this
test
is
running.
The
following message is returned:
SUPERVISORY
TEST ACTIVE

CHANNEL

NOT

AVAILABLE:

LBACK

The data channel on the other unit may be
used for all supervisory functions except
initiating Link LBACK tests.

3-7

Table 3-2

Control Module Pushbutton Controls (Cont)

Pushbutton Switch

Description

Parameter Protect (PP)

PP is pressed IN to protect parameter
settings stored in NVROM (nonvolatile
read only memory). When the PP switch is
pressed IN, it takes effect only after
the unit is either reset (by means of the
SR switch) or reinitialized.
When parameter protect is in effect,
system, 1 ink, or channel parameters may
be changed, but the new values are not
stored in NVROM. This means that when
units are either reset or reinitialized,
any parameters changed when the PP switch
was in effect return to the original
setting.
When a parameter is changed and the PP
swi tch is
in effect,
the
following
message is returned to the supervisory
terminal:
<302> ERROR
UNIT LOCKED

System Reset (SR)

COMMAND

'COMMAND

LINE':

This switch performs three functions:
1.

During normal operation, when pressed
IN, the power-up test cycle is run,
which clears the status, date, and
time
counters,
flushes
channel
buffers, and logs the operator out of
the supervisory command handler. THIS
ACTION
INTERRUPTS
DATA
TRAFFIC.
Parameter settings are NOT affected.

System reset allows the unit to
recognize that the PP switch has been
pressed IN.

In manual maintenance mode, the SR
swi tch starts loopi ng sel f-tests 0 r
the LBACK tests.

3-8

Table 3-3

Control Module LED Indicators

LED Indicator

Description

Send Data (SD)

ON indicates that the DFM unit is transmitting data on the link.

Receive Data (RD)

ON indicates that the DFM unit is receiving data on the link.

Carrier Detect (CD)

ON indicates that the modem connected to
the DFM unit (whether integral or external) is detecting a carrier signal on the
link (CD signal raised by the modem) •
CD is also ON when the units are directly
connected (no modems), and the link connection has been verified.

Send ARQ (SA)

ON indicates that the unit has not received acknowledgement of a frame and is
resending it.

Receive ARQ (RA)

ON indicates that the unit has detected a
data error and will not acknowledge the
frame.

Channel Data Error (CE)

If the CE LED is either ON or BLINKING,
data has been lost on at least one
channel.
Blinking indicates that a framing error
or parity error has occurred on one of
the channels. When it remains ON, a data
overrun or buffer overflow has occurred.
Channel errors may be cleared either individually by means of the CLEAR command
or all at once (along with system and
link counters) with the SR switch.

Network Ready (NR)

ON indicates that both DFM units are
ready, communication is established (link
is up), and parameters are compatible.
OFF indicates that the units are not communicating.

3-9

Table 3-3

Control Module LED Indicators (Cont)

LED Indicator

Description
The NR LED blinks to indicate one of the
following:
1.

The unit has received no communication from the other DFM uni t for at
least 5 seconds,

The unit has retransmitted a frame at
least Ie times wi th no acknowledgement from the other unit, or

The CTS signal has been lost on the
link for at least 5 seconds.

Each of the above generates an alarm
message <110> (see Table 6-7). After
either one minute of NR blinking or lee
unsuccessful retransmits, whichever comes
first, the unit automatically repowers.
Device Ready (DR)

ON indicates that the DFM unit has passed
self-test diagnostics and is ready.
After the unit has completed self-tests,
DR never should be OFF.
The DR LED blinks to indicate one of the
followi ng :
1.

Both uni ts are set to ei ther master
or slave,

Both units are set to invalid, or

There has been an error reading
parameter settings from the the NVROM
(nonvolatile read only memory) •

Each of the above generates an
message <311>. See Table 6-7.

3-10

alarm

LEOS
SO
RD

(SEND DATA)--~
(RECEIVE DATA) _ _~

(CARRIER DETECT)

SA
RA
CE
NR
DR

(SEND ARQ)----.
(RECEIVE ARQ)---.
(CHANNEL DATA ERROR
(NETWORK READY)-_.............
(DEVICE READY)--...........II ...~

PUSHBUTTON SWITCHES
M1

(MAINTENANCE 1)

M2 (MAINTENANCE 2)
PP

(PARAMETER PROTECT)

(SYSTEM RESET)-~

CONTROL MODULE
(LOCATION SLOT 3)

TK-10660

Figure 3-3

Table 3-4

Channel Module LED Indicators

LED Indicator
Channels 1
Channels 9

Control Module Pushbuttons and LEOs

Description
8

Any of these LEOs ON indicates data activity (either transmit or receive) on the
corresponding channel number.

3-11

LEOS

C1 (CHANNEL 1)-..-r
C2 (CHANNEL2)----~
C3 (CHANNEL 3) --flK.A
C4 (CHANNEL 4 ) -............

4-CHANNEL EXPANDER MODULE
(LOCATION SLOTS 4 & 5) .

LEOS

C1 (CHANNEL1)--~~
C2 (CHANNEL2)--~KA
C3 (CHANNEL 3) ---t1lLA
C4 (CHANNEL4)----t1lW"
C5 (CHANNEL 5)-~~
C6 (CHANNEL 6) -----~
C7 (CHANNEL 7)
C8 (CHAN N EL 8) __---r"'Ir.;:
a-CHANNEL EXPANDER MODULE
(LOCATION SLOTS 4 & 5)

TK-10659

Figure 3-4

Line Module Indicators

3-12

DF127/DF129
MODEM MODULE

SEND DATA
RECEIVE DATA
CARRIER DETECT
CLEAR TO SEND
REQUEST TO SEND
SIGNAL QUALITY
FALLBACK
TEST MODE

DF124 MODEM
MODULE

SEND DATA
RECEIVE DATA
CARRIER DETECT
DATA TERMINAL READY
MODEM READY
OFF HOOK
HIGH SPEED
TEST MODE

0 SO
0 RD
0 CD
0 TR
0 MR
0 OH
0 HS
0 TM

LEOS

LOCAL LOOP
TEST PATTERN
REMOTE LOOP

LEOS

PUSH BUTTONS

DIGITAL LOOP
FALLBACK
FALLBACK SPEED

LOCAL LOOP
SELF TEST
REMOTE LOOP
PUSH BUTTONS

DF126 MODEM
MODULE

DIGITAL LOOP
HIGH SPEED

SEND DATA
RECEIVE DATA
CARRIER DETECT
DATA TERMINAL READY
MODEM READY
CLEAR TO SEND
REQUEST TO SEND
TEST MODE

DATA/TALK

SERIAL
NUMBER

LABEL

LEOS

LOCOAL LOOP
SELF-TEST
REMOTE LOOP
PUSHBUTTONS
DISABLE MODEM
FALLBACK
DATA/TALK

MKV8S-2032

Figure 3-5

Modem Module Pushbuttons and LEDs

3-13

Table 3-5

Link Modem Front Panel Switches/LED Matrix

Function

OF124

OF126

OF127

DF129

X
X
X

X
X

X
X
X
X

X
X
X

X
X

LEOs
Send Data (SO)
Receive Data (RO)
Carrier Detect (CD)
Clear to Send (CS)
Request to Send (RS)
Signal Quality (SQ)
Fallback (FB)
Test Mode (TM)
Terminal Ready (TR)
Modem Ready (MR)
Off Hook (OH)
High Speed (HS)

X
X

X
X
X

X
X

X
X
X

X
X

Switches
Local Loop (LL)
Test Pattern (TP)
Remote Loop (RL)
Digital Loop (DL)
Fall b a c k (FB )
Fallback Speed (FS)
Self-Test (ST)
Disable Modern (OM)
Data/Talk (D/T)
High Speed (HS)

X
X

X
X
X
X
X

X
X

3-14

X
X
X
X

X
X

Table 3-6

Link Modem Front Panel LED Indicators
Indicator Status

LED Indicator

OFF

Send Data (SD)

Modem is transmitting data.

Modem is not transmitting data.

Receive Data (RD)

Modem is receiving
data.

Modem is not receiving
data.

When blinking on the
DF124 or DF126 modem,
it indicates that
errors are being
detected when self-test
loopback tests are run.
Carrier Detect (CD) Audio carrier from a
remote modem is
present.

Carrier from a remote
modem is not present.

Clear to Send (CS)

Modem is ready to
accept data from
the DTE.

Modem is not ready to
accept data from the
DTE.

Request to Send
(RS)

DTE has data to
send.

DTE does not have any
data to send.

Signal Quality
(SQ)

When continuously
ON, signal quality
is poor. When
blinking, signal
quality is marginal.

Signal quality is
satisfactory.

Fa 11 ba c k ( FB )

Modem is operating
at fallback speed.

Modem is operating at
no rmal speed.

Data Terminal
Ready (TR)

Data terminal equipment (DTE) is ready
to send or receive
data.

Data terminal equipment
is not ready to send
or receive data.

Modem Ready (MR)

Modem is ready to
send or receive data.

Modem is not ready to
send or receive data.

Off Hook (OH)

Modem is connected to
a dial-up telephone
line and the handset
is off hook.

Telephone handset is
not off hook.

3-15

Table 3-6

Link Modem Front Panel LED Indicators (Cont)
Indicator Status

LED Indicator

OFF

High Speed (H5)

Modem is prepared
to operate at high
speed.

Modem is prepared to
operate at low speed.

Test Mode (TM)

Modem is in test mode. Modem is not in test
mode.
When blinking on the
DF127 or DF129 modem,
it indicates that
errors are being
detected when self-test
loopback tests are run.
Power-UF self-test
failures on DF127 or
DF129 mode~s are indicated by TM and
SQ blinking together.

3-16

Table 3-7

Link Modem Front Panel Pushbutton Controls
Pushbutton position

Pushbutton Switch

OUT

Local Loop (LL)

Modem is placed in
analog loopback test
mode.

Normal position. Analog
loopback is disable~.

Self-Test (ST)
or
Test Pattern (TP)

Modem is placed in
test mode sending a
test pattern.

Normal position. Test
pattern is disabled.

Remote Digital
Loop (RL)

Remote modem is placed
in digital loopback
mode. For DF126 modem,
applies to private
line only.

Normal position. Remote
digital loop is disabled.

Digital Loop (DL)

Modem is disabled (out
of service) and placed
in local digital loopback mode.

Normal position. Local
digital loopback is
disabled.

High Speed (HS)

DF124 modem is conditioned to operate at
1200 bits/s instead of
the normal 24~0 bits/s.

DFl24 modem is conditioned to operate at
the normal speed of
2400 bits/s.

DATA/TALK (D/T)

Conditions the DF124
modem for voice communications.

Conditions
the
DF124
modem for serial binary
data communications.

Disable Modem (DM)

The-DF126 modem is
disabled (out of
service) and is forced
OFF HOOK, presenting a
busy condition to the
line.

The DFl26 modem is
enabled for normal
operation.

Fallback (FB)

Modem is conditioned to
operate at the lower
( fa 11 b a c k ) speed.

Modem is conditioned to
operate at the higher
(no rmal) speed.

Fallback Speed
(FS)

Selects the lower fallback speed for DF127/
DFl29 modems.

Selects the higher
fallback speed for
DF127/DF129 modems.

3-17

3.5 PREINSTALLATION BENCHTEST AND OPERATOR FAMILIARIZATION
The preinstallation benchtest and familiarization procedure is
designed to familiarize operators with the use of a DFM unit prior
to installation at local and remote sites. This procedure ensures
that the DFM units are functioning properly after shipment. The
procedure is divided into four parts.
•

Logging on with USER and SYSTEM MANAGER passwords

•

Setting system parameters

•

Enabling a data channel to enter command mode

•

Demonstrating switched channel operation

The preinstallation test configuration consists of:
•

A pair of DFM units.

•

Either a piece of phone wire (or other compatible
4-wire cable) if integral modems are used, or a null
modem cable (BC22L cable or equivalent, see Appendix C).

•

An asynchronous terminal
(for example, VTlli:Jli:J)
associated cable (BC22E cable or equivalent).

and

An asynchronous terminal is used for this test procedure. The test
procedure assumes a speed of 121i:J1i:J bits/s and data format of 8-NONE
(8 bits, no parity).
If another speed or data format is used,
appropriate DFM channel settings must be made in the procedure.
The preinstallation test procedure includes entering commands
(first on one unit, then on the other) before the units are linked
together.
3.5.1

Logging on with USER and SYSTEM MANAGER Level Passwords

STEP 1

POWER-UP SELF-TEST
Plug both units into wall outlets. LEDs on all modules
flash as the power-up test sequence is executed.
When
the self-test is complete, only the device ready (DR) LED
on both control modules will be ON.

STEP 2

CONNECTING TO SUPERVISORY COMMAND CHANNEL
Using
the
BC22E cable or equivalent,
connect
an
asynchronous terminal to the supervisory command channel
connector (J17) on one of the units. Press the RETURN key
several times. The DFM password prompt appears on the
terminal screen:
LOGON:
PASSWORD?>

3-18

STEP 3

USER LEVEL LOGON
All DFM units come from the factory with passwords set to
"SUPER" for SYSTEM MANAGER level and ·USER" for the USER
level.
At the password prompt enter USER followed by
<RETURN>. The standard header line and USER level prompt
(USR» appears:
4-15-84
USR>

STEP 4

12:00

DFM Series - ICP " "

Level 1.1

USER LEVEL COMMANDS
Press the RETURN key. The system displays the limited set
of commands that are accessible via the USER password:
LOGOUT MONITOR REPEAT SHOW

(or Ay)

"Users" can display current settings (SHOW command),
moni tor error counts and other statistics,
repeat
selected commands, or simply logout.
STEP 5

USER LEVEL LOGOUT
Enter LOGOUT followed by <RETURN>. (It is necessary to
log out of one privilege level before entering another.)

STEP 6

SUPERVISORY LEVEL LOGON
After pressing a few more RETURNS to display the logon
password prompt, enter SUPER, followed by a <RETURN> and
then another <RETURN> at the SYS> prompt. The system
displays the full range of commands available to the
system manager.
Entr ies: BROADCAST CANCEL CLEAR COpy DISCONNECT
CONNECT LOGOUT MONITOR REPEAT RESTART SET SHOW TEST
(or "'Y)

Val id

These commands are used to SET (program), MONITOR, or
TEST various channel, system, or link categories as well
as BROADCAST messages to data
channels,
COpy one
channel's configuration to another, CONNECT or DISCONNECT
switched channels, and so on. Chapter 5 describes each
command in detail. Control Y is used to abort any partial
command or system output.

3-19

3.5.2
STEP I

Setting System Parameters
SET SYSTEM DEFAULT
The system is programmed (that is, parameters are set to
specific values) with the SET command. To assure a known
starting point for all parameters, enter the following o~
whichever unit will be the master.
SYS> set system default <RETURN>
This command sets all system, link, and channel parameters to their default settings (see Table 6-4). The DFM
unit reinitializes as it stores the default parameter
settings.
Because this would interrupt current data
traffic, the system warns the user with:
WARNING

COMMAND MAY RESTART SYSTEM
USE (CONTROL Y) TO ABORT COMMAND
<CR> TO CONTINUE

This response appears wi th all commands that reset or
reinitialize the system. Continue by pressing RETURN.
<RETURN>
Re-initializing the unit.
The unit goes through a standard power-on procedure with
the LEDs cycling until the DR LED comes ON. To continue,
press two RETURNS to display the available options again.
STEP 2

SET LINK SPEED
If the units contain integral modem modules, go to Step
3. Before two units can communicate, they have to be set
to the same link speed. The default setting for link
speed is sync, which is appropriate when the units are
connected via synchronous modems.
For the units to be directly connected (via null modem
cable -- BC22L-XX) the link speed must be set to async as
shown below.
SYS> set link speed async <RETURN>
Setting the link speed also causes system reinitialization.

3-20

STEP 3

SET SYSTEM TYPE
The defaul t (factory) setting for all system types is
master. Before two units can communicate, one of the
units must be set to slave. Disconnect the terminal cable
from J17 on the master uni t, connect it to J17 on the
slave unit, and logon using the SUPER password. From the
SYS> prompt enter:
SYS> set system type slave <RETURN>

STEP 4

SET SYSTEM CONFIGURATION
The default setting for the system configuration option
is valid. Before two units can communicate, one must be
changed to invalid.
The purpose of thisoption is
explained in Section 6.5.3. On the slave unit, enter:
SYS> set system config invalid <RETURN>
Setting the configuration
reinitialization.

option

also

causes

system

STEP 5

SET SLAVE LINK SPEED
If using the integral modems, go to Step 6. If units are
going to be connected with the null modem cable, set the
link speed on the slave unit to async as in Step 2.

STEP 6

LOGOUT ON SLAVE, CONNECT TO MASTER
Enter LOGOUT on the slave unit, disconnect the terminal
cable from the slave unit, and connect the cable to the
master. One or two RETURNS should display valid entries.
The DR (device ready) LED should still be ON at both
control modules.

STEP 7

CONNECTING THE UNITS
If the null modem cable is used, it is plugged into
connector JIB on both units. If integral modems are being
used, the units are connected with a piece of telephone
wire (or any other compatible 4-wire cable) to connector
J19 on both units. Figure 3-6 shows how units with
integral modems are connected.
The inset in Figure 3-6 shows the connector slots to
insert a small screwdriver to open the connecting points
of connector JI9.
To open the spring clip, insert and
twist the small screwdriver until the points open. Hold
until
the
correct wire
is
inserted,
release
the
screwdriver, and the connection is made.
Once connected, the device ready (DR), network ready (NR)
and carrier detect (CD) LEOs of both DFM units should be
ON.
These ind i cate tha teach dev ice is ready, the 1 ink
is up, and a carrier signal is being detected.

3-21

,,_0 __
000100

Cl8~~

SUPERVISORY
COMMANO
CHANNEl (SCCI
CONNECTOR JI7(F)

LINK
CONNECTOR J18(M)

PRIVATE
UNE
CONNECTOR JI9

FUSE

4·WIRE DIRECT CONNECTION
IDF1 26 'DF1 27DF1 29,

4·WIRE LEASED
TELEPHONE CONNECTION
(OF126/0F127/0F129)

2·WIRE IOF1 24) CONNECTION
PRIVATE
LINE
CONNECTIONS

RX
LOCAL MODEM
INSERT SMALL SCREW ORIVER AND TWIST TO
OPEN SPRING CLIP

1oIKV8S-201'

Figure 3-6

Integral Modem Link Connections

3-22

STEP 8

SET SYSTEM PARAMETERS
Set the following system parameters.
SYS> set time <current time: 00:00 to 24:00>
SYS> set date <current date: mm-dd-yy>

The unit responds with each new setting when RETURN is
pressed. Notice that the new settings are entered in the
standard header line when a RETURN is entered.
12-31-83
SYS>
STEP 9

12:00

DFM SERIES-ICP " "

DISPLAY SYSTEM PARAMETERS
Display system parameters
command.

Level 1.1

entering

the

following

SYS> show system <RETURN>
The system displays all system parameters as shown below.
System parameters:
NAME
=""
TYPE
=MASTER
CONFIG =VALID
COMCHAR =lCIC
CHANNELS=8

AUTODISC
SW-STOPBITS

=20 SW-DATAPAR =8-NONE
=1 SW-SIGNALS =ASSERT

Notice the value for the COMCHAR (command character)
option.
This option can be set to anyone or two hex
characters rang ing from 00 to IF. The defaul t (factory)
setting for the COMCHAR is two characters (ICIC in
hexadecimal). On Digital Equipment Corporation terminals,
IC corresponds to a CONTROL/BACKSLASH. This allows a data
channel operator to switch from data mode to command mode
by pressing CONTROL/BACKSLASH twice.
NOTE
For non-Digital Equipment Corporation
terminals, determine which key sequence
corresponds to the hex lC character (see
Table 6-3).

3-23

3.5.3

Entering Data Channel Command Mode

STEP 1

SHOW CHANNEL 1 PARAMETERS
Display the current settings for
the following command.

Channel 1 by entering

SYS> show channell <RETURN>
System response is:
Channel parameters:
1 TYPE
=ASYNC
R-FLOW =NONE
FILLCHAR=0
COM TERM =NONE
STEP 2

L-SPEED =1200
R-SPEED =1200 L-FLOW =NONE
DATAPAR =8-NONE STOPBITS=l
SIGNALS =ASSERT
PRIORITY=NORMAL ECHO
=NONE MESSAGES=NONE
COM ECHO =NONE

ENABLE CHANNEL 1 TO ENTER COMMAND MODE
The channel parameters that must be changed are COMTERM
(command terminal) and COMECHO (command echo); they must
be set to local. Also, FLOW (flow control) must be set to
a value consistent with the terminal being used for the
test.
The commands are shown below.
Also, following
each command, the unit responds with ·Parameter Saved".
SYS> set channell comterm local <RETURN>
SYS> set channel 1 comecho local <RETURN>
SYS> set channel 1 L-flow xon-T <RETURN>

STEP 3

SUPERVISOR LOGOUT
Enter LOGOUT at the SYS> prompt. Both the supervisory
channel and a data channel cannot be logged into the
supervisory command program at the same time.

STEP 4

CONNECT TO USER CHANNEL 1
Move the terminal cable from the SCC to Channel 1
(connector Jl) on the same unit. Press the RETURN key to
display the data channel command prompt as shown below.
DFM Series-ICP ""
Level:l.l
Channel:l
Data Channel Command Selection
SEL>
The SEL> prompt indicates that the data channel is in
command mode at the operator level. No password is
required. pressing RETURN displays valid data channel
operator commands as shown below.
SUPERVISOR TERMTEST EXIT

3-24

Supervisor

Allows an operator to access the supervisory
channel from a data channel when the correct
password is entered.

Termtest

Allows an operator to start Pattern or Echo
tests for that channel, without a password.
These tests do not
interfere with other
channels.

Exit

Returns the channel to data mode.

STEP 5

3.5.4

LOGON TO USER CHANNEL AS SUPERVISOR
Enter SUPERVISOR at the SEL> prompt. The system prompts
for a password.
Entering the USER or SYSTEM MANAGER
password puts the operator in the same command mode
described in Section 3.5.1.
Switched Channel Operation

STEP 1

CONNECT AND LOGON TO SUPERVISORY COMMAND CHANNEL
Return the channel to data mode by entering EXIT followed
by pressing the RETURN key. Reconnect the terminal cable
to the supervisory channel (connector J17). Since you
logged out from the supervisory channel earlier, enter
several RETURNS for the system to again prompt for a
password.

STEP 2

SET CHANNEL 1 PARAMETERS
The remainder of the benchtest demonstrates switched
channel operation. All channels will be set to channel
type = switched.
This is done in two steps; first,
enter:
SYS> set channel I type switched <RETURN>
Next, copy this channel type to the remaining channels by
using the following command:
SYS> copy 1 all <RETURN>

3-25

STEP 3

SHOW CHANNEL I SWITCHED PARAMETERS
To verify that the channel type was correctly changed
from asynchronous to swi tched, execute a SHOW CHANNEL
command.
SYS)show channel I

<RETURN)

TYPE =SWITCHED

LOCAL:
SPEED =1200
FLOW
=NONE
ECHO =DISABLED MESSAGES=DISABLED
ID
=(A)
GROUPACCESS=(A)
SIGNALS=PASS
COMECHO =DISABLED
REMOTE:
SPEED =1200
FLOW
=NONE
ECHO =DISABLED MESSAGES=DISABLED
ID
=(A)
GROUPACCESS={A)
SIGNALS=PASS
COMECHO =DISABLED

FILLCHAR=0
PRIORITY=NORMAL
COMTERM=DISABLED
AUTODISC=DISABLED
FILLCHAR=0
PRIORITY=NORMAL
COMTERM=DISABLED
AUTODISC=DISABLED

Notice the settings for COMTERM,
options. Proceed to the next step.
STEP 4

COMECHO,

and

FLOW

SET OTHER CHANNEL I PARAMETERS
Notice the difference in channel parameters between async
(see Section 3.5.3) and switched channel types. Local and
remote switched channels are treated independently by the
DFM unit.
Also, since channel type has changed, all
parameters are set to their default values for switched
channels. To enable a switched channel to enter command
mode, COMTERM and COMECHO must be enabled.
In addition,
FLOW (flow control) must be set to a value consistent
wi th the terminal be i ng used for the test.
Execute the
following commands to set these features.
sys)set channell local comterm enabled <RETURN)
sYs)set channell local comecho enabled <RETURN)
sYs)set channel I local flow xon-t <RETURN)
terminals)

3-26

(for DIGITAL

STEP 5

COpy CHANNEL I TO ALL CHANNELS
To make all channels the same as Channel I, use the COpy
command as shown below.
SYS>copy I all <RETURN>
The system responds with:
Channel I copied
Channel 1 copied
Channel 1 copied
Channel 1 copied
Channel I copied
Channel I copied
Channel I copied
Channel 1 copied

STEP 6

to 1
to 2
to 3
to 4
to 5
to 6
to 7
to 8

DISCONNECT FROM SUPERVISORY COMMAND CHANNEL AND CONNECT
TO USER CHANNEL I
LOGOUT from the supervisory channel and reconnect the
terminal cable to Channel I (connector JI).
Press the
RETURN key to display the SEL> data channel command
prompt. Press RETURN again (at the SEL> prompt) to
display the commands that are available in this mode.
They are:
CONNECT DISCONNECT SUPERVISOR TERMTEST STATUS EXIT(OR

~Y)

Notice CONNECT, DISCONNECT, and STATUS. These are additional commands that are available on switched channels.
They are not available on asynchronous channels. Enter:
SEL> connect 2 remote <RETURN>
The system response is:
Connected to Remote Channel 2
This indicates that Channel 1 on the local unit is now
connected through the link to Channel 2 on the remote
unit. As soon as a switched channel is connected to
another, it is put directly into data mode. Whenever a
channel is in data mode, normal data transfer between
the two channel ends i~ possible.
To verify the
connection, enter data on the terminal keyboard and
observe both channel LEOs (Channel 1 local and Channel 2
remote) •
Whenever a key is pressed, both channel LEOs
light.

3-27

STEP 7

SHOW SWITCHED CHANNEL STATUS
To change from data mode to command mode, use the
COMCHAR.
Press the CONTROL/BACKSLASH keys twice to
reenter command mode. At the SEL) prompt, enter:
SEL) status <RETURN)
A message showing the connection is displayed:
Connected to Channel 2 Remote
SEL)

STEP 8

DISCONNECT SWITCHED CHANNELS
To disconnect from remote Channel 2, enter:
SEL) disconnect <RETURN)
A message appears indicating the disconnect.
Disconnected From Channel R:2
SEL)
When a switched data channel is not connected to another
channel, it cannot be put into data mode.
Thus, users
cannot EXIT from the SEL) prompt until they are connected
to another switched channel.

STEP 9

SETTING UNITS BACK TO DEFAULT
To simplify later configuration of the units, set them
both
to
the
default
settings.
This
is
done
by
reconnecting the terminal cable to Jl7 (on both units),
logging on with the SUPER password, and entering:
SYS) set system default <RETURN)

This finishes
the preinstallation test and
familiarization
process. For detailed information on each of the DFM commands,
refer to Chapters 5 and 6.
3.6 INSTALLATION
After the pretest and familiarization process, the two DFM units
may be placed at the planned local and remote locations.
These
locations may be relatively close to where the pretest was
per fo rmed or they may be miles away.
Once they reach the final
destination, remove the front bezel and verify that all modules
are firmly seated in both units before power is applied.
There are three DFM configurations using:
•

Integral modems,

•

External link modems (no integral modems), and

•

Direct connections (null modem cable).

3-28

DFM units with an integral modem module connect to the telephone
line via connector J19 on the back of the unit.
Figure 3-6
illustrates how units with integral modems are connected to either
end of the phone line.
The inset in Figure 3-6 shows the points of insertion for a small
screwdriver to open the connecting points of connector J19. To
open the spring clip, insert and twist the small screwdriver until
the points open. Hold until the correct wire is inserted, release
the screwdriver, and the connection is made.
DFM units without an integral modem connect to an external
standalone modem by means of a BC22F cable and connector Jl8 on
the back of the unit. Refer to modem manufacturer's instructions
for installation instructions.
Null modem DFM units (no modems)
to directly connect at J18.

use a BC22L cable or equivalent

Before two DFM uni ts can communicate,
must be set:

the

following

parameters

•

Link speed (on both uni ts) is set to sync for use wi th
synchronous modems (including the integral modem, if
installed), and async for use with either asynchronous
modems or a direct connection.

•

System type on one unit must be set to slave.

•

If the configuration of each unit is not identical, then
the configuration option on one unit must be set to
invalid.

Once these parameters have been set, and the units are properly
connected, LEDs DR (device ready), NR (network ready), and CD
(carrier detect) should be ON. If not, refer to Chapter 7.
3.6.1 DFM Cabling
Refer to Section 2.8 for a list of system cables and a description
of cabling requirements.
3.6.2 Installing Module Options
There are two possible module options that can be user installed:
•

An integral modem, and

•

A channel expansion module.

When installing a module, it is necessary to power down the unit
by unplugging the power cord before inserting the module.

3-29

Before powering the system down, it is important to notify all
active users that the system is to be powered down for maintenance
purposes. The first consideration in upgrading the DFM system is
pro pe r p 1 ann i ng and use r not i f i cat ion ina d van ceo f the eve n t •
Notification can be given by using the BROADCAST command with a
message • SYSTEM WILL BE DOWN FOR 30 MINUTES 3/21/86 AT 6 P.M.·
Note that only channels with the message option enabled will get
this message.
Once the system is powered down, remove the front bezel and insert
the expansion module in the correct slot (see Figure 3-1), making
sure the module snaps firmly into the backplane connector.
3.6.2.1 Installing Integral Modems -- Guidelines for
the integral modem module are listed below.

installing

•

Disconnect the current link connection; that is, remove
the cable attached to Jl8 (at both DFM units), and

•

Reconnect the link using connector J19* (at both DFM
units). See Figure 3-6 for connections.

The DFM series integral modem is installed in Slot I of the DFM
enclosure (see Figure 3-1). The DF127 or DF129 modem is typically
used as the integral modem. The DFM unit is available with these
modules already installed in the DFM enclosure (DFMXX-AB includes
DF127, or DFMXX-AC includes DF129) or modem modules may be shipped
separately and installed later.
Other modern modules may be used
as the integral modem, as discussed in Appendix B, but they must
be ordered and installed separately.
It is necessary to verify that the modern options are configured
correctly to operate with the DFM unit. DFM integral modern module
options are set at the factory for general purpose use.
These
factory selections may not be correct for use with the DFM unit.
The module must be checked, therefore, and changed to the correct
option selections, if necessary (see Appendix B for selections).

* This, of course, assumes that an integral modern module is being
installed at both ends. In remote area configurations it is
possible, although unlikely, to install an integral modem module
at one end and have the other end connected to a compatible
external modern.

3-30

3.6.2.2 Installing Channel Expansion Modules -- Guidelines
installing the channel expansion module are listed below.

for

•

The first channel line module position (Slot 4) must be
equipped with an a-channel module before expanding to
Slot 5 with a 4- or a-channel line module. A user cannot
expand to Slot 5 if Slot 4 contains a 4-channel module.

•

It is not necessary to install an expansion line module
at both DFM units. The units are not required to have an
equal number of channels. This is the main advantage of
the DFM unit's contention feature.

•

Cabling for
installed.

•

Once the expansion channel line module is installed and
the DFM unit repowered, the new channels must be
programmed to the desired parameters.

•

The Configuration Worksheet
updated and redistributed.

the

additional

channels must

be correctly

(see Chapter 6)

should

When the un its are powe red ON, the LEDs on the new mod ul e wi 11
sequence ON/OFF during the self-test routine.

3-31

CHAPTER 4
USING THE DFM UNIT
4.1 INTRODUCTION
This chapter examines a few typical DFM configurations with
various types of hardware components and the steps required to set
up the DFM unit to accommodate the different characteristics of
the hardware.
Emphasis is placed on switched channel capabilities because of its
complexity and flexibility.
Before continuing with this chapter, it is necessary to fully
understand the commands and how to use them (see Chapter 5) and to
understand how the DFM unit works (see Section 3.5).
4.2 UNSWITCHED CHANNELS
Asynchronous, synchronous, and DDCMP channel types do not have
switching capability.
This means that the device on the local
channel always communicates with the device connected to its
corresponding remote channel end.
For example, Channell on the
local end can only communicate with Channel 1 on the remote end.
When a device is powered ON, it is automatically connected to the
device at the other end, provided it is also powered ON.
No
commands are needed to establish a connection.
VT220 TERMINAL

COMPUTER

SUPERVISORY
COMMAND
CHANNEL (SCC)

MKV85·2012

Figure 4-1

Typical Asynchronous Configuration

4-1

Figure 4-1 is an example of an unswitched type of configuration.
A VT 220 t e r min a l i s con n e c ted to a 10 cal sit e and nee d s a
dedicated connection to a VAX computer at the remote site.
Channell is programmed as an asynchronous channel type. In this
example, the VT220 terminal is able to log on to the VAX computer
as soon as it is powered ON.
Asynchronous channel types can be programmed to enter command mode
to access the supervisory channel. Synchronous and DDCMP channel
types cannot access command mode.
4.3 SWITCHED CHANNELS
A switched channel can communicate with any other switched channel
provided that the devices are asynchronous and the security
feature allows the connection. Synchronous devices cannot be
connected to switched channels.
Swi tching can occur locally (such as two terminals sharing one
printer in the same office) or switching can occur remotely (such
as two terminals at one site sharing a VAX port at the other
site) •
Each end of the switched channel must be programmed separately.
When the supervisory channel is being used to program the DFM unlt
and a SHOW CHANNEL command is entered, both local and remote
parameters are shown.
The local parameters are those that apply
to the channel end from which the supervisory channel is being
used.
The remote parameters apply to the same channel at the
other DFM unit. Both switched channel ends can be programmed from
one DFM unit.
4.3.1 Remote Switching Application
The configuration of Figure 4-2 shows how a DECmate system and a
Rainbow system at one location can share a VAX port at another
location. An LN03 printer is also shared at the terminal site so
that the output of the VAX computer can be printed. The following
procedure demonstrates what steps are necessary to program this
configuration.

4-2

'I'L ~

~
.

-::-=.

DECmate

n
.I~-----I

REMOTE

LOCAL

RAINBOW

VAX COMPUTER

lN03 PRINTER

SUPERVISORY
COMMAND
CHANNEL (Scq

MKV85-2013

Figure 4-2

Typical Remote Switched Configuration

STEP 1

Connect the DECmate to the supervisory channel. Connect
the Rainbow to Channel 2 and the printer to Channel 3 at
the local DFM unit.

STEP 2

At the remote DFM unit, connect a VAX port to Channel 1
and another VAX port to Channel 3.

STEP 3

Use the WPS CX communications program on the DECmate to
access the DFM supervisory channel.
Set up system and
link parameters as described in Section 3.5.2 making the
local DFM uni t the master and the remote DFM uni t the
slave.

4-3

STEP 4

Assigning group IDs
At the DECmate, enter the following.
SYS>Set group D DECMT,R RNBOW,V VAX <RET>
SYS>Show group <RET>
following:

The DFM uni t

responds wi th the

Current Group Names are:
D = DECMT
R = RNBOW
V = VAX
STEP 5

Setting Channel Parameters
The channel type is set to swi tched.
Channel speed,
flow control, and ID must be set accordingly.
Group
access is set by listing the IDs of the devices that
each swi tched channel is allowed to access.
Set the
channel parameters as follows.
For the DECmate on local Channell:
SYS>Set channell type switched <RET>
Parametet saved.
SYS>Set channell local speed 9600, flow Xon*-B,
comecho enable, comterm enable <RET>
Parameter saved.
Parameter saved.
Parameter saved.
Parameter saved.
SYS>Set channel 1 local id D, groupaccess RV <RET>
Parameter saved.
Parameter saved.
For the VAX port on remote Channell:
SYS>Set channell remote speed 9600,
signals assert* <RET>
Parameter saved.
Parameter saved.
Parameter saved.
SYS>Set channel 1 remote id V <RET>
Parameter saved.

4-4

flow Xon*-b,

For the Rainbow on local Channel 2:
SYS>Copy 1 2 <RET)
Channel 1 copied to 2
SYS)Set channel 2 local id R, groupaccess DV <RET)
Parameter saved.
Parameter saved.
For the LN03 printer and VAX computer on Channel 3:
SYS )Set channel 3 type async,
9600 <RET)
Parameter saved.
Parameter saved.
Parameter saved.

I-speed 9600,

r-speed

SYS)Set channel 3 I-flow xon-t, r-flow xon-c <RET)
Parameter saved.
Parameter saved.
NOTE
The VAX system manager must designate
the LN03 printer as a "spoolW device.
Set the remaining channels to unused:
SYS>Set channel 4 type unused <RET)
Parameter saved.
SYS) copy 4 5 <RET)
Channel 4 copied to 5
SYS> copy 5 6 <RET)
Channel 5 copied to 6
SYS> copy 6 7 <RET)
Channel 6 copied to 7
SYS) copy 7 8 <RET)
Channel 7 copied to 8
To verifiy that all of the channel parameters have been
correctly programmed, execute a SHOW CHANNEL ALL command
as shown below.
SYS)show channel all <RET)

4-5

The DFM unit responds with the following:
1

TYPE

=SWITCHED

LOCAL:
FLOW
=XON*-B
SPEED =9600
ECHO =DISABLED MESSAGES=DISABLED
ID
=(D)
GROUPACCESS=(RV}
COMECHO =ENABLED
SIGNALS=NONE
REMOTE:
SPEED =9600
FLOW
=XON*-B
ECHO =DISABLED MESSAGES=DISABLED
ID
=(V)
GROUPACCESS=(A}
SIGNALS=ASSERT* COMECHO =DISABLED
2

AUTODISC=DISABLED
FILLCHAR=0
PRIORITY=NORMAL
COMTERM=DISABLED
AUTODISC=DISABLED

TYPE =SWITCHED

LOCAL:
SPEED =9600
FLOW
=XON*-B
ECHO =DISABLED MESSAGES=DISABLED
ID
=(D)
GROUPACCESS=(RV)
COMECHO =ENABLED
SIGNALS=NONE
REMOTE:
FLOW
=XON*-B
SPEED =9600
ECHO =DISABLED MESSAGES=DISABLED
ID
=(V)
GROUPACCESS=(A)
SIGNALS=ASSERT* COMECHO =DISABLED

FILLCHAR=0
PRIORITY=NORMAL
COMTERM=ENABLED

TYPE
=ASYNC
R-FLOW=XON-C
FILLCHAR=0
COMTERM =NONE

L-SPEED =9600
DATAPAR =8-NONE
PRIORITY=NORMAL
COMECHO =NONE

4 U TYPE

=UNUSED

(Was ASYNC)

5 U TYPE

=UNUSED

(Was ASYNC)

6 U TYPE

=UNUSED

(Was ASYNC)

7 U TYPE

=UNUSED

(Was ASYNC)

8 U TYPE

=UNUSED

(Was ASYNC)

4-6

FILLCHAR=0
PRIORITY=NORMAL
COMTERM=ENABLED
AUTODISC=DISABLED
FILLCHAR=0
PRIORITY=NORMAL
COMTERM=DISABLED
AUTODISC=DISABLED
R-SPEED =9600 L-FLOW =XON-T
STOPBITS=l
SIGNALS =ASSERT
ECHO
=NONE MESSAGES=NONE

STEP 6

Logging Out
After all channel pa ramete rs are set correctl y,
LOGOUT at the SYS> prompt.

enter

SYS>logout <RET>
The DFM unit responds with:
Logged Out
LOGON:
PASSWORD?>
STEP 7

Disconnect the DECmate from the supervisory channel and
connect it to Channell.
Load communications for the
DECmate (refer to DECmate user' s documentation).
Press
RETURN to display the command channel prompt (SEL».

STEP 8

AT the SEL) prompt, enter C (for CONNECT)
RETURN.

followed by

SEL>C <RET>
The DFM unit responds with
switched channels:

the

for

selecting

Valid Entries: <A to Z> or <1 to 16> (or "Y)
D = DECMT
R = RNBOW
V = VAX
CONNECT>
STEP 9

Enter V at the displayed connect prompt.
CONNECT>V <RET>
The DFM unit responds with a message indicating the
connection:
SEL>Connected to Remote Channel 1
The DECmate is now connected to the VAX computer. Press
RETURN and log on to the VAX computer.

STEP 10

Enter terminal mode on the Rainbow, press RETURN once or
twice to display the SEL> prompt, and repeat Steps 8 and
9 from the Rainbow.
When request for the VAX computer
is made (V), the DFM unit responds with:
SEL>REQUEST FOR GROUP V QUEUED

4-7

STEP 11

Log out of the VAX computer from the DECmate, then press
CONTROL/BACKSLASH twice to recall the SEL) prompt.
At
the SEL) prompt, enter d (for DISCONNECT) followed by
RETURN.
SEL>d <RET>

The DFM unit responds with:
Disconnected From Channel R:l
SEL>
As soon as the DECmate disconnects from the VAX
computer, the queued Rainbow on local Channel 2 is
automatically connected to the VAX computer.
The user
on the Rainbow can now log on.
There can be more than one VAX port assigned through
switched channnels.
Each port is assigned the same
group ID of V. When a terminal user wants to connect to
a VAX computer and C is entered, followed by V,
connection is made to any free VAX port in the V group.
4.3.2 Local Switching Application
The configuration of Figure 4-3 shows how two personal computers
can share a letter quality printer and an asynchronous modem
through one DFM unit.
The following procedure demonstrates that
the DFM unit can be used as a PC switch so that common peripherals
can be shared. The steps necessary to program this configuration
are as follows.
STEP 1

Connect a Rainbow to the supervisory channel. Connect a
DECmate to Channel 2 and the printer to Channel 3 at the
DFM unit.
Connect an asynchronous modem to Channel 4.
Refer to Table 2-1 for required cables.

STEP 2

Enter terminal mode by typing T at the main screen of
the Ra inbow.
Press RETURN several times to access the
supervisory channel.

STEP 3

At the logon password prompt, enter:
LOGON:
PASSWORD)super <RET)
The DFM unit responds with:
SYS>

4-8

RAINBOW

r
'---=_--.-.-..-.-.

I - I--,\ )

;

LQP02 PRINTER

MODEM
MKV85-2014

Figure 4-3
STEP 4

Local Switching Application

Reinitialize the DFM unit
At the SYS> prompt, enter:
SYS)set system default (RET>
The DFM unit responds with the warning message.
WARNING ---- COMMAND MAY RESTART SYSTEM
USE (CONTROL Y) TO ABORT COMMAND
<CR) TO CONTINUE

4-9

STEP 5

Assigning group IDs
At the SYS prompt, enter the following.
SYS>Set group D DECMT, L LQP02, R RNBOW, M MODEM <RET>
Parameter saved.
Parameter saved.
Parameter saved.
Parameter saved.
SYS>Show group <RET>
following:

The DFM unit

responds with the

Current Group Names are:
D = DECMT

L = LQP02

R = RNBOW
M = MODEM

STEP 6

Setting Channel Parameters
All channel types are set to swi tched.
Channel speed,
flow control, and ID must be set accordingly on the
local DFM unit only. Group access is set by listing the
IDs of the devices that each switched channel is allowed
to access. Set the channel parameters as follows.
For the Rainbow on local Channell:
SYS>Set channell type switched, comecho enable,
comterm enable <RET)
Parameter saved.
Parameter saved.
Parameter saved.
SYS>Set channell local speed 9600, flow Xon-B <RET)
Parameter saved.
Parameter saved.
SYS)Set channel 1 local id R, groupaccess LM <RET)
Parameter saved.
Parameter saved.
For the DECmate on local Channel 2:
SYS>Copy 1 2 <RET)
Channel 1 copied to 2
SYS>Set channel 2 local id D, <RET)
Parameter saved.

4-10

For the LQP02 printer on local Channel 3:
SYS>Copy 1 3 <RET>
Channel 1 copied to 3
SYS>Set channel 3 local id L, groupaccess RD <RET>
Parameter saved.
Parameter saved.
For the modem on local Channel 4:
SYS>Copy 3 4 <RET)
Channel 3 copied to 4
SYS>Set channel 4 local id M, I-speed 1200, signals
dial* <RET)
Parameter saved.
Parameter saved.
Parameter saved.
To verify that all of the channel parameters have been
correctly programmed, execute a SHOW CHANNEL ALL command
to display parameters.
STEP 7

Logging Out
After all channel parameters are set correctly,
LOGOUT at the SYS> prompt.

enter

SYS>logout <RET>
The DFM unit responds with:
Logged Out
LOGON:
PASSWORD?>
STEP 8

Disconnect the Rainbow from the supervisory chann~~ and
connect it to Channell. The Rainbow must use MS -D~~
Version 2.11 or above for this appl ication (poly-COM
communication software can also be used).

STEP 9

Enter termina~ mode from the Rainbow by typing T at the
main screen.
Press RETURN a few times to display the
command channel prompt (SEL»).

MS-DOS is a trademark of Microsoft Corporation.
poly-COM is a trademark of Polygon Associates, Inc.

4-11

STEP la

At the SEL) prompt, enter C (for CONNECT)
RETURN.

followed by

SEL> C (RET>
The DFM unit responds with
switched channels:

the

for

Valid Entries: (A to z> or (1 to 16> (or
D = DECMT
L = LQP02
R = RNBOW
M = MODEM

selecting

"'Y)

CONNECT>
STEP 11

Enter L at the displayed connect prompt.
CONNECT> L (RET>
The DFM unit responds with a message indicating the
connection:
SEL>Connected to Local Channel 3
The Rainbow on Channel
printer.

now connected

the

STEP 12

To p r i n t a d 0 c urn en t, ret urn t o t hem a ins c r e e n 0 f the
Rainbow and select the drive containing the MS-DOS
operating system. Use the SETPORT command at the MS-DOS
prompt to set the communications port characteristics.
Use the XMODE command to redirect printer output to the
communications port.
Refer to the MS-DOS user's
documentation for more details.

STEP 13

Print the document using the MS-DOS PRINT command.

STEP 14

When the pr int routine is completed, return to command
mode by typi ng the command character.
Then en te r
DISCONNECT at the SEL) prompt to release the printer.

To allow the DECmate on Channel 2 to access the printer, the
following steps would be used.
STEP 1

The DECmate must have WPS operating system Version 2.1
or above for this application.
Enter CX at the main menu of the DECmate, then press
RETURN a few times to access the command channel prompt
<SEL>.

4-12

STEP 2

To connect to the pr inter on Channel
following at the <SEL) prompt:

enter

the

SEL>C L <RET>
The DFM unit responds with a message indicating the
connection:
SEL>Connected to Local Channel 3
STEP 3

Return to the main menu at the DECmate and set the
communications port characteristics using the SO and CC
commands.

STEP 4

At the rna in menu, select the document to be pr inted.
Redirect the printer output to the communication port by
changing the document destination code to CLQP and
proceed to print the document.

To connect to the modem on Channel 4, the following steps would be
used.
STEP 1

At the SEL> prompt, enter:
SEL>C M <RET>
The DFM unit responds with a message indicating the
connection:
SEL>Connected to Local Channel 4
The DECmate or Rainbow is now connected to the modem,
which allows the user to dial a remote device.

STEP 2

To dial a number,
tion.

refer to the modem user's documenta-

The examples in this chapter show two very simple switched configurations. In complex configurations using eight or more channels,
it is important to use the Configuation Worksheet (see Section
6 • 2) •
Wit h 0 u t
h a r d - copy
d i a gram s
0 f
the
con fig u rat ion ,
programming
a
large configuration could
be
confusing
and
compl i ca ted.

4-13

CHAPTER 5
COMMAND DESCRIPTIONS

5.1 GENERAL
This chapter provides detailed descriptions of each DFM command,
including where used, command line format (syntax), and one or
more examples of each. Commands are listed in alphabetical order.
5.2 SUPERVISORY COMMAND HANDLER
The supervisory command handler processes commands entered on the
supervisory channel. Either the USER or SYSTEM MANAGER password is
required to log onto it. The type of password that is entered
determines which commands can be entered.
Only one user can log into the supervisory command handler at any
one time. It is directly accessed via the supervisory channel
(connector J17) on the back of the unit.
The supervisory command handler may also be indirectly accessed
from data channels when the channel is in data channel command
mode (see Section 5.3).
PASSWORD LEVELS
Before any supervisory command can be entered, the password prompt
appears:
LOGON:
PASSWORD?>

Supervisory commands are divided into two categories: those
available with the USER password, and those available with the
SYSTEM MANAGER password.
The default settings for USER and SYSTEM MANAGER level passwords
are USER and SUPER, respectively. Passwords may be changed wi th
the SET command. After either password is entered, the system
indicates the privilege level by the prompt that is given:
USR> for "user" level privileges
SYS> for "system manager" privileges
A third level of commands, Data Channel Operator commands, is
available to channel operators. This level requires no password.
The operator command level is indicated by the SEL> prompt.
5.3 DATA CHANNEL COMMAND MODE
In addition to data mode, asynchronous and switched channel types
can operate in command mode if enabled to do so (synchronous
channels cannot enter command mode) •

5-1

Asynchronous and swi tched channels are enabled to enter command
mode by the following options:
•

COMTERM
Option (command terminal) -- For asynchronous
channels, COMTERM must be set to local, remote, or both
to enable command mode.
For switched channels, there is a separate COMTERM option
for each end, which must be set to enabled.

•

COMECHO Option (command echo) -- This option determines
whether command input is echoed by the DFM unit or not.
Like the COMTERM option, it must be set to local, remote,
or both for asynchronous channels, and enabled for a
switched channel end.

•

COMCHAR Option (command character) -- This option is set
to the same value for all channels at the system level.
When entered, the command character(s) enable a data
channel to communicate with the DFM unit via supervisory
commands. For the COMCHAR to be recognized, however, the
COMTERM option must be set appropriately. The default
value for the COMCHAR option is two hex IC characters.
Hex IC corresponds to a control-backslash sequence on
Digital Equipment Corporation's terminals. For other
terminals, verify the key sequence that corresponds to
hex IC.

Refer to Section 3.5.3 (part of the preinstallation benchtest)~ for
a description of wEnabling a Data Channel to Enter Command Mode w•
5.4

DFM COMMAND STRUCTURE

5.4.1 Command Levels
DFM commands are divided into the following levels of access or
system control. Also provided are the commands that are available
at each level.
•

Data Channel Operator commands (no password required)
Asynchronous type channel:
SUPERVISOR TERMTEST EXIT
Switched type channel:
CONNECT DISCONNECT STATUS SUPERVISOR TERMTEST EXIT

•

USER Password Level commands
LOGOUT MONITOR REPEAT SHOW

•

(or~Y)

SYSTEM MANAGER Password Level commands
BROADCAST CANCEL CLEAR COPY DISCONNECT CONNECT
MONITOR REPEAT RESTART SET SHOW TEST (or~Y)

5-2

LOGOUT

When a data channel enters command mode, Data Channel Operator
commands can be executed wi thout having to enter a password. To
access the broader range of commands, the supervisor command must
be entered. The DFM unit then prompts for a password.
The USER or SYSTEM MANAGER password is required at logon before
any other commands can be entered.
5.4.2 DFM Command Prompting
DFM command structure allows inexper ienced users to step through
complete command strings, one step at a time. Before anything is
entered, or at any point of an incomplete command, a RETURN can be
entered and the DFM unit prompts for "Valid command, Entries".
When an incomplete or otherwise erroneous command is entered, the
system responds wi th the partial command that was accepted, and
prompts the user for the next valid entry. Notice in the example
the partial commands appearing instead of the SYS> prompt:
EXAMPLE 5-1: USING RETURN AT THE SYS> PROMPT
Command Input: SYS> <RETURN>
Unit Response: Valid
Entries:
BROADCAST
CANCEL
CLEAR
COpy
DISCONNECT CONNECT LOGOUT MONITOR REPEAT RESTART
SET SHOW TEST (or~Y)
(Date)
SYS>

(Time) DFM Ser ies - ICP ""

Level: (REV)

EXAMPLE 5-2: USING RETURN AFTER THE FIRST VALID ENTRY
Command Input: SYS> set <RETURN>
Unit Response: Valid Entries: SYSTEM CHANNEL LINK
SET>

(or~Y)

EXAMPLE 5-3: USING RETURN AFTER THE SECOND VALID ENTRY
Command Input: SET> link <RETURN>
Unit Response: Valid Entries: SPEED DELAY (orAy)
SET LINK>

5-3

EXAMPLE 5-4: USING RETURN AFTER THE THIRD VALID ENTRY
Command Input: SET LINK> speed <RETURN)
Unit Response: Valid Entries: SYNC ASYNC (orAy)
SET LINK SPEED)

EXAMPLE 5-5: USING RETURN AFTER THE FOURTH VALID ENTRY
Command Input: SET LINK SPEED> sync <RETURN>
Unit Response: WARNING ---- COMMAND MAY RESTART SYSTEM
USE (CTRL Y) TO ABORT COMMAND
<CR) TO CONTINUE
Control Y (Ay) can be entered to abort the SET command, which
results in the following unit response.
(Date)
SYS>

(Time) DFM Series - ICP .... Level: (REV)

Entering a RETURN causes the unit to
the following response:
Parameter saved.
SYS>

5-4

reinitialize,

resulting

5.5 DFM COMMAND DESCRIPTIONS
Thi s section prov ides deta i led desc r iptions of all the commands
that are available with the DFM unit.
The command descriptions
are in alphabetical order.
These descriptions include privilege
level usage, defini tions, the correct command str ing format, and
one or more examples.

BROADCAST
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[ ]

[ 1

[Xl

DEFINITION: The BROADCAST command is used by the system manager to
send any desired message to data channels at both ends
of the system. Only channel ends with the message
option enabled receive broadcast messages.
When sent from the supervisory channel, a message may
consist of 256 characters (about 4 lines), but each
line must be separated by a backslash (\).
When sent from a data channel enabled for supervisory
commands, a message can only be a maximum of 74
characters (1 line).
EXAMPLE 5-6: BROADCAST MESSAGE
Command Input:
SYS>Broadcast System will be down tonight from 7:88 to 8:88 p.m.
<RETURN>
Unit Response:
Message sent.
SYS>

5-5

CANCEL
PRIVILEGE LEVEL:
[ ]

Data Channel Operator
User Password
System Manager Password

[ ]
[X]

DEFINITION: The CANCEL command is used to terminate either a test
function or any command that is being repeated (using
the REPEAT command). When CANCEL is entered, the DFM
unit returns to the system manager prompt.
NOTE
Control Y (Ay) or a return <RETURN> have
the same effect as CANCEL.
EXAMPLE 5-7: CANCELING A TEST SEQUENCE
To cancel a test sequence, first initiate a test sequence.
START TEST
Command Input: SYS>test channell pattern <RETURN>
Unit Response: Test initiated.
TEST CHANNEL 1 PATTERN>
CANCEL TEST
Command Input: TEST CHANNEL 1 PATTERN> cancel <RETURN>
Unit Response: Test terminated.
SYS>

5-6

CLEAR
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

]
[ ]

[

[Xl

DEFINITION: The CLEAR command is used to reset error counters back
to zero. It allows the system manager to clear either
individual counters or groups of counters as specified
in the command line. When system is selected, all
counters (channels and link) are cleared.
FORMAT:
COMMAND

CATEGORY

OPTION

VALUE

Clear

SYS

None

LINK

ACtivity

XMitutil, RECVutil, ALL

STats

TRansmit,RECEive,
LINKDrop, ALL

L-Stats,

FRamerr, PARerr,
R-Stats, BUFrovrf,
DATAOvrn, ALL

CHannel<No. or ALL>

NOTE
Allowed abbreviations for entries are
shown in capital letters.
EXAMPLE 5-8: USING THE CLEAR COMMAND
Command Input: Sys>clear channel all r-stats parerr <RETURN>
Unit Response: Cleared.
SYS>

5-7

CONNECT
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[Xl

[ ]
[Xl

DEFINITION: The CONNECT command is used to connect one swi tched
channel to another. It may be used from ei ther the
supervisory channel (system manager password) or a
switched channel that is in data channel command mode.
From switched channels, no password is required for
use.
A switched channel end may be connected to any other
switched channel (either local or remote) provided
access is granted by the group access option for each
channel. (See Channel ID/Group Access Options, Section
6.8.3.10, for a description of switched channel access
and identification).
Switched channels are disconnected by either the
DISCONNECT command or the automatic disconnect feature
(see AUTODISC Option, Section 6.5.4).
CONNECTING TO A GROUP
If a channel group name is specified in the CONNECT command
string, the group name (a single letter) must be a valid entry as
determined by the group access option or the connection will be
denied. Each channel can be assigned to one or more groups using
the SET command to specify those groups in the group access
option.
If access is authorized, connection will be made to the
first available channel (not busy) in that group. If all channels
in a group are busy, the request is queued, and the requesting
channel will be connected to the first available channel in that
group.
Explicit channel number and channel end may also be specified in
the CONNECT command, but group access is still checked by the
system. Whether a group or explicit channel is specified, channel
connections are made on a first come, first served basis. Requests
remain queued until either a connection is made or the request is
withdrawn via the DISCONNECT command.

5-8

CONNECT (CONT)
EXAMPLE 5-9: CONNECTING FROM A SWITCHED ~ATA CHANNEL
Specifying explicit channel number and channel end:
Command Input:

SEL) connect 3 remote <RETURN>

Unit Response:

SEL) Connected to Remote Channel 3

Specifying a Group ID:
Command Input:

SEL) connect a <RETURN>

Uni t Response:

Connected to Local Channel 2. (Connection is
made to the first available channel in group
a)

When the CONNECT command is followed by a RETURN, the DFM uni t
prompts for valid entries and displays group "names". A group name
is a descriptive name (up to five characters) for a group that is
represented by a letter when used wi th the CONNECT command. (See
the SET command description for information on how to set group
names. )
EXAMPLE 5-10: CONNECTING FROM THE SUPERVISCRY CHANNEL
Specifying explicit channel number and channel end:
Command Input:

SYS) connect 2 local 3 local <RETURN>

Unit Response:

Connection completed.

Specifying a Group ID:
Command Input:

SYS) connect 2 local a <RETURN>

Unit Response:

Connection completed.

Whether a connection is attempted ~rom a data channel or the
supervisory channel, if the requesting channel does not have
access to the specified channel or group (that is, the channel ID
or group letter does NOT appear in that channell s group access
assignment), the following message is returned:
ILLEGAL: SECURITY VIOLATION; ACCESS DENIED.

5-9

CONNECT (CONT)
If an attempt is made to connect to a different channel while a
previous request is still pending or the channel is connected, the
following responses are displayed.
EXAMPLE 5-11: CONNECTING FROM THE SUPERVISORY CHANNEL
(Channel Busy)
Command Input:

SYS> connect 7 local 1 remote <RETURN>

Unit Response:

Channel 7 not disconnected
This response appears if the busy channel (Channel
7) is at the same end as the supervisory channel
being used,
or
Channel Busy, Request Denied
This response appears if the busy channel (Channel
1) is at the other end of the supervisory channel
being used.

EXAMPLE 5-12: CONNECTING FROM A SWITCHED DATA CHANNEL
(Channel Queued or Busy)
Command Input:

SEL> connect 1 local <RETURN>

Unit Response:
(if queued)

Inuse: Already Requesting Channel 8 Local
SEL>

Unit Response:
(if connected)

Inuse: Already Connected to Channel 8 Local
SEL)

If two remote channel ends are specified by the supervisory
channel of the local uni t (or vice versa), the system responds
with:
Request forwarded to Remote Unit.
In this case, it is necessary to execute a SHOW SWITCHED command
to see if the connection has been made or is queued.
When a connection has taken place, channels are placed in normal
data mode. Entering the COMCHAR sequence returns the terminal to
the command mode, where the operator can execute one of the other
commands, for example, DISCONNECT.

5-10

COpy
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[ ]
[ ]
[X]

DEFINITION: The COpy command is used to copy one channel's
configuration (parameters) to another. It allows the
system manager to copy the entire parameter configuration of one channel to another selected channel or to
all channels.
When identical or even similar configurations are
planned for several channels, the COpy command can
greatly speed the programming process. Enter the
parameters in one channel and then copy its configuration to the channels that are similar. Minor changes
for individual channels can then be programmed.
FORMAT:
COpy <source channel no.> <destination channel no. (or ALL»
NOTE
Specify only the channel number. Do not
enter the word "channel."
EXAMPLE 5-13: COPY ONE CHANNEL TO ALL CHANNELS
Command Input:

SYS> copy 2 all <RETURN>

Unit Response:

Channel 2 copied
Channel 2 copied
Channel 2 copied
Channel 2 copied
Channel 2 copied
Channel 2 copied
Channel 2 copied
Channel 2 copied

to 1
to 2
to 3
to 4
to 5
to 6
to 7
to 8

SYS>

5-11

DISCONNECT
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password
DEFINITION:

[Xl
[ ]
[Xl

The DISCONNECT command is used to terminate a
connection between two swi tched channels. It may be
issued either from a data channel (in command mode) or
from the supervisory channel. A data channel operator
can only disconnect that channel's current connection
by entering DISCONNECT at the SEL) prompt (no password
required) •
The system manager can disconnect any current connection by specifying a channel number and channel end
(that is; local or remote). For example, assume local
Channel 2 is connected to remote Channel 5. The
connection can be disconnected by the system manager
specifying either "disconnect 2 local" or "disconnect
5 remote".
Whether a disconnect is performed from a data channel
or the supervisory channel, a message indicating the
disconnection is sent to both ends of the connection.

EXAMPLE 5-14: DISCONNECTING FROM SWITCHED DATA CHANNELS
Command Input: SEL> disconnect <RETURN>
Unit Response: Disconnected From Channel R:2
SEL>
or
Channel Not Connected: No Disconnect Necessary
SEL>

5-12

DISCONNECT (CONT)
EXAMPLE 5-15: DISCONNECTING A LOCAL CHANNEL USING THE SUPERVISORY
CHANNEL
Command Input: SYS> disconnect 2 local <RETURN>
Unit Response: Channel 2 disconnected.
or if Channel 2 was not connected;
Channel 2 Not Connected, No Disconnect Necessary.

EXAMPLE 5-16: DISCONNECTING A LOCAL CHANNEL USING THE SUPERVISORY
CHANNEL
Command Input: SEL> disconnect 5 remote <RETURN>
Unit Response: Request forwarded to Remote Unit.
If the DISCONNECT command is entered on the local unit for
disconnection of a remote channel end(s), the request is
forwarded. A SHOW SWITCHED command displays current switched
connections and must be entered to see if the DISCONNECT command
was successful.

5-13

EXIT
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[Xl

[ ]

[ 1

DEFINITION: The EXIT command is used to exit from data channel
command mode and ret urn to no rmal da ta mode. On
s wit c he d c han n e 1 s , howe v e r, i f the r e i s no cur r en t
data connection, there is no data mode (thus no reason
to exit). Entering EXIT in this situation just returns
the operator to the SEL> prompt.
Enter ing data channel command mode wi th the COMCHAR
sequence allows a temporary break in communication
without disconnecting a switched connection. When the
command activity at the SEL> prompt is completed, the
EXIT command is entered at the SEL> prompt to return
the channel to data mode.

5-14

LOGOUT
PRIVILEGE LEVEL:

[ 1
[X 1

Data Channel Operator
User Password
System Manager Password

[Xl

DEFINITION: When the LOGOUT command is entered, the operator or
system manager is logged out of the supervisory
command handler. The supervisory command handler can
only be logged into from one location at a time (data
channels or supervisory channel) •
Entering LOGOUT on a terminal connected to the
supervisory channel returns the channel to an idle
state and the password prompt. Entering LOGOUT at the
data channel USER or SYSTEM MANAGER password level,
returns the data channel to the operator (no password)
command level (SEL». Entering EXIT at the SEL)
prompt, returns the channel to data mode.
EXAMPLE 5-17: LOGGING OUT
Command Input: SYS) logout <RETURN>
Unit Response: Logged Out
LOGON:
PASSWORD>

5-15

MONITOR
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[ 1
[X]

[Xl

DEFINITION: This command displays the MONITOR information for
system, channel, or link categories. Using the REPEAT
function with the MONITOR command provides a periodic
update of the information being monitored (see REPEAT
command) •
FORMAT:
MONITOR SYSTEM
LINK
CHANNEL <channel number or "all">
EXAMPLE 5-18: MONITOR SYSTEM
Command Input: SYS> monitor system <RETURN>
Unit Response:
SYSTEM
DEVICE STATUS=READY
NETWORK STATUS=READY
CHANNEL ACTIVITY:
1
Xmt=185 Avg Xmt=180
2
Xmt=192 Avg Xmt=175
3
Xmt=175 Avg Xmt=265
4
Xmt=7260 Avg Xmt=645

Rcv=192
Rcv=199
Rcv=180
Rcv=0

Avg
Avg
Avg
Avg

Rcv=285
Rcv=278
Rcv=274
Rcv=0

(chars/min)
(chars/min)
(chars/min)
(chars/min)

LINK ACTIVITY:
XMITUTIL= 84% RECVUTIL= 48%
Channel and link activity are explained in Examples 5-19 and 5-20.
NETWORK STATUS: Either reads "READY" or one of the following:
*PROBLEM: LINK DOWN
*PROBLEM: NO CTS (on the link)
*PROBLEM: NO RECEIVE
*PROBLEM: TRANSMIT RETRIES
Each of these problems causes the NR LED on the control module to
blink. Refer to Table 3-3 for a description of each problem.

5-16

MONITOR (CONT)
DEVICE STATUS:

Either reads "READY" or one of the following:
*PROBLEM: NVROM BAD/DISABLED
*PROBLEM: BOTH UNITS INVALID
*PROBLEM: BOTH UNITS MASTER
*PROBLEM: BOTH UNITS SLAVE

Each of these problems causes the DR LED on the control module to
blink. Refer to Table 3-3 for a description of each problem.
EXAMPLE 5-19: MONITOR LINK
Command Input: SYS> monitor link <RETURN>
Unit Response:
Link TRANSMIT RECEIVE LINKDROP total
1

XMITUTIL= 92%
RECVUTIL= 84%

EIA Signals= CAR XCK RNG RCK DSR DTR CTS RTS
0
0
0
0
0
1
0
1

Link counters are cleared automatically when the system is reset.
TRANSMIT:

Number of transmit errors for
link counter was last cleared.

RECEIVE:

Number of errors received by the unit since the
counter was last cleared.

LINKDROP:

A linkdrop occurs when there is a severe enough
interruption in communication between two units for
the DFM unit to automatically reinitialize.

the local

unit since

The front panel NR LED blinks for one minute prior to
reinitialization. See Table 3-3 for a description of
conditions that interrupt communication and cause the
NR LED blink.
XMITUTIL:

Transmit utilization of the link is the number of
characters transmitted on the link divided by link
capacity multiplied by 100. The calculation for this
figure is made every 15 seconds, which is then added
to the the previous total, and the sum is divided by
2. Thus, this figure is heavily weighted toward
recent utilization.

5-17

MONITOR (CONT)
RECVUTIL:

Receive utilization of the link is defined in a
fashion corresponding to XMITUTIL (previous page).

EIA Signals: Indicated ON by a I and OFF by a 0. The link presents
a DTE interface, so the DFM outputs DTR and RTS on
the link. CAR, DSR, and CTS are input signals.
XCK/RCK:

Transmit clock/receive clock. When link speed is set
to async, receive and transmit clocks are generated
by the DFM units. When link speed is set to sync, the
connected modem must generate clock signals. Both
clocks should always be indicated ON when the units
are transmitting and receiving data.

EXAMPLE 5-20: MONITOR CHANNEL
Command Input:

SYS> moni tor channel 1 <RETURN>

Unit Response:
Chan

FRAMERR

PARERR

BUFROVRF

DATAOVRN

subtotal

total

-------~-----R----L-----R----L-----R-----L------R-------L-----R---------

1
000
XMITDATA=NUL 00h
RECVDATA= " > 3Eh
ACTIVITY:
Xmt=93

0
000
000
EIA Signals= CAR RCA RNG RRI DSR DTR CTS RTS
1
0
0
0
1
0
1
0
Avg Xmt=82
Rcv=10l
Avg Rcv=80
(chars/min)

XMITDATA, RECVDATA, ACTIVITY and EIA Signals appear only when a
sing 1e channel is moni tored. Thi s info rmat ion is on-1 ine data,
which means it can change while it is being monitored.
XMITDATA:

The last
channel.

RECVDATA:

The last character received on the monitored channel.

ACTIVITY:

Xmt = number of characters transmitted (by terminal)
over the last minute.
Avg Xmt = average number of
characters transmitted per minute for the last 20
minutes.

character

transmitted

the

monitored

Rcv = number of characters received by terminal in
last minute. Avg Rcv = average number of characters
received per minute for the last 20 minutes~
EIA Signals: Indicated ON by a 1 and OFF by a 0. Channels present
a DCE inter face, so the DFM uni t outputs CAR, RNG,
DSR, and CTS to the terminal. The DFM unit receives
RCA, RRI, DrR, and RTS from the terminal.

5-18

MONITOR (CONT)
When DDCMP and synchronous channels are monitored, only buffer
overflow errors are displayed. Framing, parity, and data overrun
errors do not apply to synchronous channel operation.
For DDCMP channels only, header CRC errors are counted and appear
in the parity columns.
XMITDATA, RECVDATA, ACTIVITY, and EIA Signals categories apply to
both synchronous and asynchronous channels. When the DFM unit
reads characters appearing on synchronous channels, however, it is
possible that the register will be bit-shifted. This means that
XMITDATA and RECVDATA values (appearing in hex) may not accurately
reflect the character actually transmitted or receIved.

5-19

REPEAT
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[ 1
[X]

[Xl

DEFINITION: The REPEAT command allows the system to repeat certain
commands at specified intervals for a specified number
of repeti tions. Whenever REPEAT or any two commands
are entered on one line, they are separated by a
semicolon (;).
The repeat command allows the operator to specify the
number of times, and the time interval in seconds for
a selected command to be repeated. A REPEAT function
may run indefinitely by entering an asterisk (*) in
the repetitions field.
When used wi th the BROADCAST command, it must be the
first command because any data following the BROADCAST
command is considered text. A repeating command is
terminated by pressing RETURN or entering any other
command.
FORMAT:
Monitor link; REPEAT <repetitions>: <interval in seconds>
(1 to 65,535)
(1 to 65,535)
EXAMPLE 5-21: REPEAT MONITORING A CHANNEL
Command Input: SYS>MONITOR CHANNEL 1; REPEAT 4:5 <RETURN>
Unit Response: The following response is updated and displayed
four times at five second intervals.
Chan
FRAMERR
PARERR
BUFROVRF
DATAOVRN
subtotal
total
-------L-----R----L-----R----L-----R-----L------R-------L-----R--------1
000
0
0
000
000
XMITDATA=NUL 00h
RECVDATA="
> 3Eh
ACTIVITY:
Xmt=93

EIA Signals= CAR RCA RNG RRI DSR DTR CTS RTS
000
1
010
1
Avg Xmt=82
Rcv=99
Avg Rcv=79
(chars/min)

5-20

RESTART
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password
DEFINITION:

[ 1
[ 1
[Xl

The RESTART command is used to reinitialize the
system while retaining the link error counters and
supervisory channel log-on condition. Parameters are
down-l ine loaded, channel buffers are cleared, and
the units are resynchronized with the RESTART
command.
When a channel type is changed, the new parameter is
automatically down-line loaded. It is recommended
that a RESTART command still be issued for resynchronization. Other major parameter changes, like link
speed, automatically restart the system.
Refer to Section 7.2 for a complete description of
self-tests and reinitialization.

EXAMPLE 5-22: SYSTEM RESTART
Command Input: SYS> restart <RETURN>
Unit Response: Reinitializing the unit
The front panel LEOs sequence through the self-test routine when
reinitialization takes place. When it is finished, pressing RETURN
twice displays the SYS> prompt.

5-21

SET
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[ ]
[ ]

[X]

DEFINITION: The SET command is used to select (program) system,
link, and channel parameters, as well as, general
categories of date,
time, alarm, and password.
Chapter 6 details the use of the SET command to select
options and values, and explains each programmable
option for system, link, and channel categories.
Other general categories used with the SET command are
shown below.
FORMAT:
SET

TIME

<00:00 to 23:59>

DATE

<mm-dd-yy>

ALARM

Disabled or Enabled (default is disabled)

PASSWORD

GROUP

<group ID> <any five character name>
(? ; , not allowed)

EXAMPLE 5-23: SETTING TIME
The time appears in DFM header lines; thus any printout of
supervisory channel output is automatically stamped with the time.
Command Input: SYS> set time 13:15 <RETURN>
Unit Response: Time set: 13:15

5-22

SET (CONT)
EXAMPLE 5-24: SETTING DATE
The date also appears in DFM header lines and the printout of
supervisory channel output.
Command Input: SYS> set date

~8-22-85

Unit Response: Date set: 8-22-85

13:18

EXAMPLE 5-25: SETTING ALARM
Alarm is set either enabled or disabled. When enabled, the
supervisory channel receives automatic system alarm messages. Note
that this option corresponds to the messages option for data
channels.
Command Input: SYS> set alarm enabled <RETURN>
Unit Response: Alarm set: Enabled
The new time, date, and alarm appear in the header line. The word
"ALARM" indicates that the supervisory channel is enabled to
receive alarm messages generated by the DFM unit. Table 6-7 lists
each alarm message.
EXAMPLE 5-26: SETTING NEW PASSWORDS
Passwords may be changed wi th the SET command for both USER and
SYSTEM MANAGER levels. The default passwords for these privilege
levels are USER and SUPER, respectively.
Command Input: SYS> set password system Smith <RETURN>
Unit Response: Parameter Saved.
or
Command Input: SYS> set password user Brown <RETURN>
Unit Response: Parameter Saved.
Passwords may be set to any combination of eight ASCII
alphanumeric characters, with the exception of question mark (?),
semicolon (i), comma (,), and a blank space. Entering any of the
exceptions in this field will have unpredictable results.

5-23

SET (CONT)
EXAMPLE 5-27: ASSIGNING GROUP NAMES
Five character descriptive "names"
are assigned
to groups
identified by a letter. Switched channel users may then be
prompted with group names as an aid to access the correct group:
For example, group A may be assigned to engineering resources
only. Thus, it would be appropriate to assign the name of ENG-l to
group A. A list of group names is displayed by the DFM unit
whenever a SHOW GROUP command is entered or the CONNECT command is
entered followed by a RETURN. The only ASCII characters that
cannot be entered in this field are question mark (?), semicolon
(;), comma (,) or a blank space. A maximum of seven groups can be
specified.
This example assigns several channels connected to the accounting
microcomputer to a group identified by the letter A.
Command Input: SYS> set group a acctg <RETURN>
Unit Response: Parameter Saved.
Group A has now
"accounting") •

been

assigned

the

name

"ACCTG"

(that

is,

Group names are listed when:
1.

A CONNECT command, followed by a RETURN is entered·on a
switched channel in command mode.
Command Input: SEL> connect <RETURN>
Unit Response: Valid Entries:<A to Z> or <1 to 16> (orAy)
A = ACCTG
E = ENG

A CONNECT command
incomplete.

from

the

supervisory

channel

Command Input: SYS> connect 1 local <RETURN>
Unit Response: Valid Entries:<A to Z> or <1 to 16> (orAy)
A = ACCTG
E = ENG
3.

A SHOW GROUP command is entered on a supervisory channel.
Command Input: SYS> show group <RETURN>
Unit Resopnse: Current Group Names are:
A = ACCTG
E = ENG

5-24

SHOW
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password
DEFINITION:

( ]
(X]

(X]

The SHOW command is used to display parameter
settings. It allows the operator to display the
current settings of all system, channel, or link
parameters. When the channel category is selected,
either one channel or all channels may be specified.
Also, wi th the SHOW SWITCHED command, the operator
can display all swi tched connections throughout the
system.
Response messages for show channel and show link
include special symbols called "state indicators"
that provide information on status. See Examples 5-29
and 5-30 for descriptions of state indicators.

FORMAT:
SHOW SYSTEM
LINK
CHANNEL <No. or "all">
SWITCHED
GROUP
EXAMPLE 5-28: SHOW SYSTEM
Command Input: SYS> show system <RETURN>
Unit Response: Syster.: Parar.lett=rs:
NA~lE=IIDECMlJX"

TYPE=MASTER
CONFIG=VALID
COMCHAR=lCIC
CHANNELS=8

AUTODISC=20
SW-DATAPAR=8-NONE
SW-STOPBITS=l SW-SIGNALS=ASSERT

5-25

SHOW (CONT)
EXAMPLE 5-29: SHOW LINK
Command Input: SYS> show link <RETURN>
Unit Response: Link Parameters:
1 E SPEED=SYNC: 19200 DELAY=NORMAL
NOTE
The letter E is a link state indicator.
See Table 5-1 for a description of link
state indicators.
If the link speed is set to sync, but no clocking signal is
detected, the response reads SPEED=SYNC: NO CLOCK. This indicates
that either the link modem is malfunctioning or that a proper
connection to the modem has not been made.
The link speed is checked during system reset or reinitialization
for response purposes only. Thus, if modem speed has fallen back
since last reset, the speed that is displayed in the response will
reflect the previous setting.
EXAMPLE 5-30: SHOW CHANNEL
Command Input: SYS> show channell <RETURN>
Unit Response:
Channel parameters:
1 E TYPE
=ASYNC L-SPEED =1200
R=SPEED =1200
R-FLOW =NONE DATAPAR =8-NONE STOPBITS=l
FILLCHAR=0
PRIORITY=NORMAL ECHO
=NONE
COMTERM =NONE COM ECHO =NONE

L-FLOW
=NONE
SIGNALS =ASSERT
MESSAGES =NONE

NOTE
The letter E is a channel state indicator. See Table 5-2 for a description of
channel state indicators.
Regardless of the size of the DFM unit, the operator can set and
show channels up to channel number 16. This is because a
16-channel uni t can be connected to a uni t wi th fewer ports to
take advantage of port contention functions. Because a larger unit
may be at the other end of the network, it is necessary to provide
the capabil i ty 0 f prog ramming a channel end that. does not ex i st on
the local unit. This is the reason for channel state indicators
(L, R, and B) that show when a channel end "does not exist" at one
or both ends.

5-26

SHOW (CaNT)
Also, when the channel type is changed to unused, and a SHOW
channel is executed, the response ind icates that the channel is
currently unused, as well as what the channel type was before it
was set to unused. This allows the channel type to be changed from
either sync, async, or switched to unused, and then back, and
still retain the original parameter settings. If channel type is
set to unused, and then to a new type, all channel parameters go
to their default values of the new selection (see Table 6-4).
EXAMPLE 5-31: SHOW SWITCHED
Command Input: SYS> show switched <RETURN>
Unit Response:

CON~ECTIONS:

Channel

L:2
L:3
L:4

L:8

L:S

SUPV CHAN

L: 1

L:6

RE')UEST~:

Channel

L ·t:,-'

Channel
L:8

EXAMPLE 5-32: SHOW GROUP
Command Input: SYS> show group <RETURN>
Unit Response: Current Group Names are:
1-. ~ ACCTG
E = Er~G
P = PERS

NOTE
Refer to the SET command for information
on how to set group names.

5-27

Table 5-1

Link State Indicators

E = One or more of the error counters for the link is incremented.
R = DFM uni t is respond ing to a Link Loopback command issued by
the other DFM unit.

Table 5-2

Channel State Indicators

E = One or more of the error counters for
incremented.

the channel has been

S = Synchronous channel being displayed.
U = Channel type set to unused.
L = Local channel end is either not functioning or nonexistent.
R = Remote channel end is either not functioning or nonexistent.
B

= Both channel ends are either not functioning or nonexistent.

> = Unit has received a "stop data" flow control signal on the
link.

< = Unit has sent a "stop data" flow control signal on the link.
# = Unit has received and sent a "stop data" flow control signal
on the link.

5-28

STATUS
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password
DEFINITION:

[X]
[ ]
[ ]

The STATUS command is used for a switched data
channel only. Its function is to show whether or not
the channel
is currently connected to another
switched channel.
If there is a connection, the unit response shows
which channel (by number) it is connected to and the
location (local or remote). I f the channel is not
connected,
a
response
message
indicating
no
connection is displayed.

EXAMPLE 5-33: SWITCHED CHANNEL STATUS
Command Input: SEL> status <RETURN>
Unit Response: Not Busy
or
Connected To Channel

(1-16)

(if there is a connection)

5-29

(Local or Remote)

SUPERVISOR
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password
DEFINITION: Entering the SUPERVISOR command at the data channel
SEL> prompt causes the log-on/password prompt to
appear. This allows the operator to access commands
that are available via the USER or SYSTEM MANAGER
passwords. The operator must enter the correct USER or
SYSTEM MANAGER password to continue, otherwise, a
Control Y must be used to abort the process.
There is a maximum time limit of two minutes to enter
a password, after which, a message is displayed that
indicates a timeout.
EXAMPLE 5-34: USING THE DATA CHANNEL SUPERVISORY COMMAND
Command Input: SEL> supervisor <RETURN>
unit Response: LOGON:
PASSWORD?>
Entering the correct password, followed by RETURN, causes the
appropriate password prompt (either USER> or SYS» to appear.

5-30

TERMTEST
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password

[Xl

[ 1
[ 1

DEFINITION: The TERMTEST command is used by data channel operators
to run a limited set of terminal tests. Tests that can
be executed without a password are:
•
•
•

Pattern test,
Local Echo test, and
Remote Echo test.

Once a test is running, it is terminated by pressing
the BREAK key.
Chapter 7 provides a complete
description of each test function.
FORMAT:
SEL> termtest pattern,
I-echo, or
r-echo <RETURN>
or
SEL> termtest <RETURN>
Valid Entries: PATTERN L-ECHO R-ECHO (or Ay)
TERMTEST>
EXAMPLE 5-35: USING THE TERMTEST PATTERN TEST
Command Input: SEL> termtest pattern <RETURN>
Unit Response: The response for the Pattern test is the complete
ASCII character set as shown below.
1"#$%' ()*+,--./0123456789: i<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\] \nl

'abcdefghijk1mnopqrstuvwxyz{{ I}}T"#$%' () *+,--./0123456789: i<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\] \nl

'abcdefghijk1mnopqrstuvwxyz{{ I}}(BREAK key pressed)
END TEST
SEL>

5-31

TEST
PRIVILEGE LEVEL:
Data Channel Operator
User Password
System Manager Password
DEFINITION:

[ ]
[ ]
[Xl

The TEST command allows the system manager to initiate a system, channel, or link test. The TEST command
must be used with caution because some of the tests
interfere with data activity on all channels.
Refer to Chapter 7 for a complete description of the
function and scope of each test, as well as warnings
about the degree of interference from each test. When
the TEST command is used, tests run until terminated
wi th ei ther a RETURN or the CANCEL command.
Notice
that the data channel TERMTEST command is terminated
with the BREAK key, whereas, the system manager's
test functions are terminated with either a RETURN or
the CANCEL command.

FORMAT:
TEST

SYSTEM
LINK
CHANNEL <no.>

POWERUP
SIGNALS, LBACK
SIGNALS, L-ECHO, R-ECHO,
PATTERN, LBACK

5-32

TEST (CONT)
EXAMPLE 5-36: USING THE LINK LBACK TEST
Command Input: SYS> test link lback <RETURN>
Unit Response: Test initiated.
TEST LINK LBack>
(8-22-85 12:04) LINK 1 LBACK: NO ERRORS
For demonstration purposes, the link cable is disconnected to
simulate a link failure. The output below indicates a linkdrop.
(8-22-85 12:06) LINK 1 LBACK: NO LOOP
TEST LINK LBACK>
When reconnected, error counts are indicated:
(8-22-85 12:12) LINK 1 LBACK: TRANSMIT=271/49% RECEIVE=67/20% LINKDROP=l
TEST LINK LBACK> cancel <RETURN>
TEST TERMINATED.
4- 2 8 - 83

1 0 : 26 S Ys t e1.. : " 11/7 0 - B (10 cal)

SYS>

5-33

Level: 0 B0

CHAPTER 6
SELECTING CONFIGURATION OPTIONS

This chapter describes each programmable configuration option of
the DFM system and guidelines on using the SET command to select
these options. In addition, the Configuration Worksheet is
provided.
Fill out a copy after deciding what option settings
your application requires.
The Configuration Worksheet is designed to be a guide for the
programming
process,
as
well
as
a
permanent
record
of
configuration/reconfiguration activity. In the event of any type
of system problems or accidental reset to default, such a record
is very important to reprogram the system.
6.1 DFM CONFIGURATION OPTIONS
Configuration options for the DFM Intelligent Communications
Processor are divided into the following categories.
•

General -- These are options of a general nature, such as
time, date, password, and so forth.

•

System -- Options set at the system level are:
Parameters which distinguish
another (for example, name).

DFM

units

from

one

Certain switched channel parameters (for example,
STOPBITS, DATAPAR) that are set at the system level
to ensure compatibility among all switched channels.
Other system-wide parameters for all channels (for
example, the command character sequence (COMCHAR)
used by data channels to enter command mode) •
•

Link -- Link options are speed and delay.

•

Channel
Channel
options
define
the
operating
characteristics of each channel.
Depending on the type
of channel selected, the options vary.

The types of options that can be selected by the SET command are
listed in Table 6-1.
6.2 THE CONFIGURATION WORKSHEET
Programming the DFM system is ~ two-step process.
•

Fill out the Configuration Worksheet as you follow along
in this chapter, selecting the proper settings as each
option is explained. Figure 6-1 is a typical configuration diagram and Figure 6-2 is a sample filled-in
Configuration Worksheet.

6-1

•

Using the SET command, program the units according to the
information on the worksheet. Section 6.3 provides guide1 i n e son us i n g the SET co mm and, wh i 1 e Sec t ion s 6 • 4
through 6.8 detail option descriptions.

A blank Configuration Worksheet for photocopying purposes is
located in Appendix D.
Table 6-1

Configuration Options

GENERAL: TIME

DATE

SYSTEM:

NAME
TYPE
SW-DATAPAR

LINK:

SPEED

ALARM

PASSWORD

GROUP (descriptive name)

CONFIGURATION
AUTODISCONNECT
COMCHAR
SW-STOPBITS
SW-SIGNALS
DEFAULT

DELAY

CHANNEL: Asynchronous Channel: TYPE
SPEED
FILLCHARACTER
PRIORITY
ECHO
COMECHO
DATAPAR STOPBITS

FLOW
SIGNALS
MESSAGES
COMTERM

Switched Channel: TYPE
SPEED
FLOW
FILLCHARACTER
PRIORITY
ECHO
MESSAGES
COMTERM
COMECHO
ID
GROUP ACCESS
SIGNALS
AUTODISCONNECT
Synchronous/DDCMP Channel: SPEED
FLOW
(non-DDCMP only) SYNFILL (DDCMP only)

BLOCKSIZE

The DFM ICP is a very powerful and flexible networking device and
must be correctly programmed. To help in the programming process,
it is important to use the Configuration Worksheet. It is equally
im po r tan t to d raw a d i a gram 0 f the con fig u rat ion s i mil a r t 0 the
one shown in Figure 6-1. Figure 6-1 is used with the Configuration
Worksheet of Figure 6-2 to provide an example of how to fill in
the worksheet. The example is a typical switching and contention
application utilizing multiple resources. Some of the most
important features, such as network security, synchronous and
asynchronous communication, and system management are covered.
6.2.1 Network Security
To restrict terminal users from unauthorized resources, the
channels are assigned a unique group access list containing only
the I D cod e s 0 f r e so u r c e s th a t the term ina 1 use r i saIl 0 we d to
use. In Figure 6-1, the DECmate user on remote Channel 10 cannot
access the data PBX or the VAX-ll/780 system at the local site
because the ID for those facilities are not included in the group
access list for Channel 10. Refer to Chart 2B of Figure 6-2 for
remote Channel 10 option selections.
6.2.2 System Management
A system manager is generally assigned to maintain network integrity of such a complex system as shown in Figure 6-1. Initial
programming of the DFM unit is done from the supervisory command

6-2

channel (SCC). Once programming is complete and the network link
is established, the system manager may choose to program his user
channel for supervisory command mode. This allows the system
manager to participate as both terminal user and system manager
from the same terminal. In the example, local Channel 1 is
selected for the system manager.
The group access list for remote Channels 7 and 8 include the
letter ·S· (system manager) which allows Channels 7 and 8 to
communicate wi th the system manager on Channel 1 to report any
network problems.
6.2.3 Synchronous/DDCMP Support
Channel 5 is establ ished as a DDCMP 1 ink between the local and
remote VAX system. This type of configuration is suitable for
applications requiring file transfers over DECnet facilities. See
Figure 6-2, Chart 3, for option selections.
6.2.4 Modem Tail Circuits
Local Channel 8 and remote Channel 11 are programmed for modem
application to allow terminal users to dial in or dial out of the
DFM network.
6.2.5 Data PBX Facility
The DFM supports a wide variety of data communications equipment.
Local Channels 2 and 3 are connected to a PBX (Private Branch
Exchange) to allow terminal users to access r~sources not directly
connected with the DFM network.
6.2.6 Asynchronous Channel Support
Channel 4 is the only channel programmed for asynchronous use.
Asynchronous applications are the most common type in statistical
multiplexer networks, however, asynchronous terminal users are
limited to a single resource. The terminal user on local Channel 4
can only communicate with the VAX system on remote Channel 4.
Ref~r to Figure 6-2, Chart 2A, for Channel 4 programming.
6.2.7 Host Systems
Local Channels 2, 3, 6, and 7, and remote Channels 1, 2, and 3 are
programmed as switched channels and are connected to host systems.
These channels have been assigned IDs of X for the PBX, A (Alpha)
for the VAX 8600, and B (Beta) for the VAX-ll/780 (refer to the
switched only section of Figure 6-2, Chart 2A). The group access
for the above system channel ends must be considered very
carefull y. The select ion should be a unique let ter tha t has not
yet been assigned. In the example configuration, the letter Z is
assigned for the group access on these system channel ends. This
restricts access to the system devices to those terminal users
that have the letters A, B, or X in their group access list.

6-3

VT220
10= R
ACC = ABMXS
OECmate
10= R
ACC = ABMP

PBX
10=X
ACC = Z

SYNC
VAX 8600
10=A
ACC=Z

RAINBOW
10=S
ACC = ABMXR

BOSTON MUX 3
REMOTE
OFM12-AC

NEW YORK MUX 1
(LOCAL)
OFM08-AC

..
DECmate

5
SYNC
VAX-11/780 .......- - - - - - 1
10= B
ACC=Z

9600 BITS/S

6
7
8
9
10 1 - 0 0 - - - - . . . "

RAINBOW
10= R
ACC = ABPXS

LN03 PRINTER
10= P
ACC= R
CHANNEL CONFIGURATION CHART

10=M
ACC = RS

CHANNEL TYPE

CHANNEL NUMBER

SWITCHED

1,2,3,6,7,8
9, 10, AND 11

UNUSED

OECmate
10= R
ACC = AMP

ASYNCHRONOUS 4
SYNCHRONOUS
(OOCMP)

LEGEND
10
ACC
SCC

10=M
ACC = RS

UNUSED

= GROUP 10
= GROUP ACCESS
= SUPERVISOR COMMAND CHANNEL

MKV85·2050

Figure 6-1

Sample Configuration Diagram

6-4

CHART 1
INTELLIGENT COMMUNICATION PROCESSOR WORKSHEET

LOCAl:

REMOTE:

LOCATION

liEU' yoB"

LOCATION

8 o.srl:' AI

MODEL 4t

l>FM" £1 - 8e-

MODel •

gEM ,Ii. - ne

SERIAL.

AIr; IY¢ 9

SERIAL 4t

N« "5~ *'

SYSTEM PARAMETERS:
NAME:

SYSTEM PARAMETERS:

8c?STO.4! - M v,\ :1

AtE..., YMk -MLIX

NAME:

16 CHARACTERS (MAX)

16 CHARACTERS/MAXI
TYPE: MASTER 0
SLAV~ •

TYPE: MASTER
SLAVE 0

1It0NFIGURATION: VALID Ii(

.CONFIGURATION: VALID

AUTODISCO.NNECT: I
TIMEOUT
.

is) "

AUTODISCONNECT: r--__- - . . . ,
TIMEOUT
C
(1 to 225 SEC)

I IV

(1 to 225 SECI

SWITCHED PARAMETERS'

SWITCHED PARAMETERS

SW DATAPAR:
PARITY: NONE t(
DATA 8)(
7 0
ODD 0
6 0
EVEN 0

SW DATAPAR:
DATA 8 J(

7 0
60

11.

PARITY: NONE
ODD 0
EVEN 0

5 IJ

SW STOP81TS

lJ(

1.5

SW STOPBITS

/Il..

SW SIGNALS: ASSERT.
PASS
0

SW SIGNALS: ASSERT
PASS
0

~ [IJ ~

COMMAND CHARACTER: [ [ ]
(HEX 00 TO 1 FI
HEX

B~IlETA

GROUP NAMES:

COMMAND CHARACTER:
(HEX 00 to 1 F)

FEX

W~ [I] ~
HEX

HEX

/I:/lI-PH/I

hl~M"Dpd" /?& I(rtR.~,)." PB)/
LINK PARAMETERS
SPEED:

SYNC )(
ASYNC 0

DELAY

NORMAL )I(
SATelLITE U

LINK CHARACTERISTICS MUST BE SET THE SAME AT BOTH ENDS

~ONFIGURATION IS VERY CRITICAl. REFER TO SECTION 6.5.3.
MKV8S-2059

Fig ure 6-2

Sample of Completed Configuration Worksheet
(Sheet 1 of 4)

6-5

CHART 2A
REMOTE

LOCAL

SPEED

1200
2400
4800
9600

AUTOBAUD
OTHER(D
FLOW

NONE

x· X X )( 4' IX 1)(

XO~B

XO~C

XO~T

.~~

CTS-RTS

I~!

~
~

OTHERQ)

I~ >

J
(/J ~ r/:rt I .... (f ¢ ¢
"F

~ F=======~~======~~~=*~~*=~=*~
FILLCHAR
(0·255,

PRIORITY

L-LOW
N=NORMAL
H=HIGH

SWITCHED:
ECHO
I - - - - - - o f E = ENABLE
MESSAGES
0 = DISABLE
1 - - - - - - - 4 ASYNC
COMTERM
N = NONE
1 - - - - - - - 4 L= LOCAL
R = REMOTE
COMECHO
B = BOTH

AUTODISC

E = ENABLE
0= DISABLE

CHANNEL 10

A TO Z

:r
u
~

GROUP ACCESS

ID-l/ST

SIGNALS

N = NONE
0= DIAL
rJIo= DIAL"

>
...J

§
III

A = ASSE~:'"
~ASSER

H N' N L 1= N N N

D ]) ~ N 1=

in D JJ

£"£ER: ])"PE
E £ Ii R ~~ ]) l1> £
£ £ ,; R ~S.]) l1:> '£

I~I~I¢I~I'I¢I¢I~I

IH IN IN IL-Iflrv IN IN I
1> jJ) J) N

,,]) l]) J;

]) J) J) I.- -E £" If"
D ]) ]) t..~ ~£ IE E'

J) lP D L

~E E £"

~~ £" £ E
£ E E .~
.~ ~ .2

S x >< ,. ! ~B 18 VY\

Z 2

N N N

CD OTHER SPEED SELECTIONS
1 =50.2=75.3=110.4=1345.5=150
6=300. 7=600. (ASYNC ONLY S=SAMEBAUDI

~I': ~:2

11 ~ I-? (t1.
4 '

1*
I>

z ~s

~ rt

3~J18MX f(

Ij:;ABlttXS
~:n8 p x..s

SPLIT-SPEED 8=7511200, 9=1200175.
10=150/2400. 11 =24001150

(2) OTHER FLOW SELECTIONS
1=XON-B, 2=XON-C. 3=XON·T.
4=DSR-DTR. 5=CTSH-RLSH.
6=CTSH-RLSl. 7=CTSL-RLSH.
8=CTSL-RLSL

MKV8!>·2060

Figure 6-2

Sample of Completed Configuration Worksheet
(Sheet 2 of 4)

6-6

CHART 28
REMOTE

LOCAL

...>
z

STOPBITS

1. 1.5.2

SIGNALS

A = ASSERT
L = L-DIAL
R = R-DIAL
B = 2-DIAL
P = PASS

DATAPAR

N = NONE
O=ODD
E = EVEN

SPEED

1200

,
l

4800

AUTOBAUD
OTHER(j)

xorlt·C

Vl
o%J

XOr.flt.T

I
\ I
I

~
4_

.!.~

OTHERa>

-<
FILLCHAR

(0·255)

PRIORITY

L-LOW
N=NORMAL
H=HIGH

ECHO
MESSAGES
COMTERM
COMECHO

I
I
1/r

...
z

CHANNEL ID

A TO Z

GROUP ACCESS

/D-lIST

N = NONE
0= DIAL

§
Vl

SIGNALS

r:JIt=DIA~

lJ) l1> "P
E€ £ •

1> E" €
]) £' IE"

E = ENABLE
D = DISABLE

I \

SWITCHED
E = ENABLE
D = DISABLE
ASYNC:
N = NONE
L = LOCAL
R = REMOTE
B = BOTH

AUTODISC

•

X X

CTS·RTS

t
~

NONE
XON*-B

,.,

FLOW

~~
~~

14~

X X

I
I

9600

II
r

2400

L=- E €

p IR ~

•

R rtl'1 RS

N N~ :

A = ASSER~~
#=ASSER

<D OTHER SPEED SELECTIONS:

(Z) OTHER FLOW SELECTIONS:

1=50. 2='75. 3=110. 4=134.5. 5=150.
6=300.7=600. (ASYfI.IC ONLY S=SAMEBAUD)

'-XON-B. 2=XON-C. 3-XON-T.
4=DSR-DTR.5=CTSH-RLSH.
6=CTSH-RLSL. 7=CTSL·RLSH.
8=CTSL-RLSL.

SPLIT-SPEED 8=75/1200. 9=1200175.
10=150/2400.11=2400/150

MI<V85-2061

Fig ure 6-2

Sample of Completed Configuration Worksheet
(Sheet 3 of 4)

6-7

CHART 3
REMOTE

LOCAL
TYPE

CHANNElS
S

=SYNC

0" DDCMP
INT 1200

SPEED

INT 1Soo
INT 2400

iX'

INT 4Soo
INT 7200
~

INT 9600

0
0

INT 1200

o2l

INT 1800

INT 2400

>
\I)

INT 4800
INT 7200
INT 9600

BLOCK SIZE

I I 1;<] 1 I I I 1

NONE

FLOW

CTS-RTS

512

1024

u
>
\I)

4096

2048

DDCMP
ONLY

2.4,6

SYNFILL

161

CHART 4

GENERAL PARAMETERS
TIME:

00:00 1023:59

ALARM:

3:LfSDATE'

MM-DD-YY

ENABLED
DISABLED

PASSWORD:
USER:
SYSTEM:

/do ... ~ -86

MKV8S-2062

Fig ure 6-2

Sample of Completed Configuration Worksheet
(Sheet 4 of 4)

6-8

6.3 PROGRAMMING GUIDELINES
System and link parameters must be programmed separately on both
local and remote DFM units. Once the units are communicating, the
channel parameters entered on one unit can be down-line loaded to
the other unit.
Down-line loading makes the programming process
easier and faster. The following sequence of steps is used to
program the DFM system after the units are powered up at local and
remote sites.
•

Decide which unit will be the "master".

•

Enter the "SET SYSTEM DEFAULT" command on the master unit
to
ensure
a
known
starting
point
for
channel
configurations (this also sets system and link parameters
to their default values listed in Table 6-4).

•

Set link speed on the master unit (sync when connected to
synchronous modems; otherwise async).

•

On the other unit (so two units can communicate):
Change the type to "slave"
Set the link speed the same as the master unit

•

Connect units (via phone line or other facility).

•

After the power-up test cycle, the units should come up
with the CD, NR, and DR LEDs all ON (it may be necessary
to press the SR swi tch once).
If not, refer to Chapter
7.

•

Enter channel parameter selections on the master unit.

•

Set the configuration
"inval id" •

•

The invalid set of parameters is automatically replaced
by the valid set, with the exception of system type,
name, and link speed (as well as date, time, and alarm).

option

the

slave

unit

6.3.1 Configuration Rules
During network configuration the following rules apply.

•

Both units cannot be master or slave.
(DR) blinks]

•

Both uni ts cannot be inval id.
blinks]

•

If both units are valid, the master unit downloads to the
slave unit.

6-9

[Dev ice Ready LED

(DR)

6.3.2 Using the SET Command
Table 6-2 is a complete listing of DFM options that are programmed
with the SET command.
In addition to system, channel, and link parameters, other general
categories selected with the SET command are:
Time:

Appears in DFM header lines; thus any printout of
supervisory channel output is automatically stamped
with the time.

Date:

Also appears in DFM header lines and the printout of
the supervisory channel output.

Alarm:

Is set ei ther enabled or disabled.
When enabled, the
word "ALARM" appears in the supervisory channel header
lines and the supervisory channel receives automatic
system alarm messages.
Note that this option
corresponds to the messages option for data channels.

Password:

May be changed with the SET command for both USER and
SYSTEM MANAGER levels. The default passwords for these
privilege levels are USER and SUPER, respectively.

Group:

Five-character descriptive "names" are assigned to
groups identified by a letter.
Switched channel users
may then be prompted with group names as an aid to
access the correct group. For example, Group A may be
assigned to engineering resources only. Thus, it would
be appropriate to assign the name of ENG-l to Group A.
A list of group names is displayed by the DFM unit
whenever a SHOW GROUP command is entered or the CONNECT
command is entered followed by a RETURN. A group name
can be any combination of five characters or numbers
with the exception of a question mark (?), a semicolon
(; ), a comma (,), or a blank space.

6.3.2.1 Setting Multiple Options -- When several options in the
same category (system, link, or channel) are programmed, options
may be separated by a comma and entered on the same command line.
The number of options that can be programmed with the same line is
limited by a maximum of 76 characters that can appear on one line.
When a comma is the last item entered on a command line, the DFM
uni t prompts for the next option to be programmed (see Example
6-1) •

6-10

EXAMPLE 6-1: SETTING MULTIPLE OPTIONS
Command Input: SYS>set channel I I-speed 4800, r-speed 4800,
I-flow xon-t, r-flow xon-c,<RETURN>
Unit Response:
Parameter
Parameter
Parameter
Parameter

saved.
saved.
saved.
saved.

Because a comma was the last character on the line, the DFM unit
prompts the operator to program the next option (DATAPAR) for
Channell:
<Next Option?> (or "Y)
SET CHANNEL 1 DATAPAR)

6.3.2.2 Abbreviations -- All commands, options, and values may be
abbreviated when entered into the system. All that is required is
to supply enough letters to uniquely identify the input. For
example, SET SYSTEM TYPE SLAVE may be abbreviated as SE SYS TY SL.
Notice that system requires three letters, because SY does not
clearly define system; there is also SYnc and SYnf.
6.3.2.3 ·Channel All· Programming -- To select all channels to
the same type (asynchronous, switched, or unused) the CHANNEL ALL
command can be specified. The "channel all" feature can only be
used to select channel type and asynchronous channel parameters.
It cannot be used to select switched channel parameters. Switched
channel parameters must be selected on a per channel basis and
then duplicated, if necessary, using the COpy command.
EXAMPLE 6-2: SET CHANNEL ALL
Command Input: SYS> set channel all type switched <RETURN>
Unit Response: Parameter saved.
Because synchronous and DOCMP channel types are only possible on
certain channels, "channel all" programming is not allowed when
setting options on these channel types.

6-11

COpy Command -- With the COpy command, an operator can
copy the configuration of one channel to another channel, or to
all
other
channels.
If
identical
or
similar
channel
configurations are planned for several channels, this command can
greatly speed the programming process.
6.3.2.4

EXAMPLE 6-3: PROGRAMMING WITH THE COpy COMMAND
(For eight-channel uni t)
Command Input: SYS> copy I all <RETURN>
Uni t Response: Channel 1 copied
Channel 1 copied
Channel 1 copied
Channel 1 copied
Channel 1 copied
Channel 1 copied
Channel 1 copied

to Channel 2
to Channel 3
to Channel 4
to Channel 5
to Channel 6
to Channel 7
to Channel 8

Some configurations cannot be copied to certain channels, however.
Synchronous and DDCMP channel configurations are allowed only on
Channels 1 and 2, 5 and 6, 9 and 10, and 13 and 14.
Trying to
copy a synchronous channel configuration to a channel without
synchronous capability results in an error message.
6.4 DFM OPTIONS AND VALUES
Table 6-2 lists all of the options and the values that can be
selected. Valid abbreviations appear in capital letters.

6-12

Table 6-2

Configuration Options and Values

Function

Option

Parameter Value

TIme

(24 hour clock:hours:minutes)
(90:99 to 23:59)

DATE

(MM-DD-YY)

AIArm

Either DISAbled or ENabled

PASSWord

(Any eight characters) Defaults
are USer and SUPER.

GROUP Access

(Five-character descriptive
name. )

NAme

Up to l6-character name

TYpe

MAster or SLave

CONFIguration

INvalid or VALId

AUTODisconnect

Time period from 1 to 255 minutes

SWItched
DATA Parity (SW-D)

5-E
5-0
5-N

SWitched STOpbits

1, 1.5, 2

SWitched SIgnals

ASSert, PASS

DEFault

Pressing RETURN after entering
default
sets
all
applicable
parameters to default values.

COMmand Character
(COMC)

One- or two-character sequence
(hex value from 00 to IF).

SPeed

ASYnc, SYNC

DELay

NORmal or SATellite

TYpe

UNUsed, ASYnchronous,
SYNChronous, or DDCMP

GENERAL

SYStem

LINK

CHannel

6-13

6-E
6-0
6-N

7-E
7-E
7-N

8-E
8-0
8-N

SWItched,

Table 6-2

Configuration Options and Values (Cont)

Function

Option

Parameter Value

ASYNC Channel Options:
Local-SPeed (L-SP)
Remote-SPeed (R-SP)

59, 75, 119, ll4.s, 159, 199,
699, 1289, 2499, 4889, 9699,
AUTOBaud, SAMebaud, or SplitSpeed at 75-1299, 1299-75,
159-2499, or 2499-159.

LOCAl-FLow Control
REMote-FLow Control

NONe, XON*-B, XON*-C, XON*-T,
XON-B, XON-C, XON-T, CTS-RTS,
DSR-DTR, CTSH-RLSH, CTSH-RLSL,
CTSL-RLSH, CTSL-RLSL

DATA Parity

5-E
5-0
5-N

6-E
6-0

6-N

7-E
7-0
7-N

8-E
8-0
8-N

STOpbits

1, 1.5, 2

SIgnals

ASSert, L-Dial (L-D), R-Dial
(R-D), 2-Dial (2-D), or PASS

FILlcharacter

Number of null characters from 9
to 255.

PRiority

LOW, NORmal, HIgh

ECho

NONe, LOCAl Unit, REMote Unit, or
BOth

Messages

NONe, LOCAl Unit, REMote Unit, or
BOth

COMmand Terminal

NONe, LOCAl Unit, REMote Unit, or
BOth

COMmand Echo

NONe, LOCAl Unit, REMote Unit, or
BOth

SWITCHED Channel Options:
SPeed

50, 75, 110, 134.5, 150, 300,
600, 1200, 2400, 4800, 9600,

AUTOBaud, or Split-Speed at
75-1200, 1200-75, 150-2400,

or 2400-150.

6-14

Table 6-2

Configuration Options and Values (Cont)

Function

Option

Parameter Value

FLow

NONe, XON*-B, XON*-C, XON*-T,
XON-B, XON-C, XON-T, CTS-RTS,
DSR-DTR, CTSH-RLSH,
CTSH-RLSL, CTSL-RLSH,
CTSL-RLSL

SIgnals

NONe, PASS, ASSERT, ASSERT*,
DIAL, DIAL*

FILlcharacter

o to 255

PRiority

NORmal, LOW, HIgh

ECho
MEssages
COMmand Terminal
COMmand Echo
AUTODisconnect

All of these options for
SWItched CHannels are either
ENabled or DISAbled.

GROUP Access

Specifies which group(s)
channel is allowed access to.
<ID List, ALL>

CHannel
Identification

< A to Z>

SYNCHRONOUS and DDCMP Channel Options:
L-SPeed
R-SPeed

INT1200,
INT4800,
EXT1200,
EXT4800,

FLow Control

NONe, CTS-RTS

BLocksi ze
(Synchronous Only)

512, 1024, 2048, 4096

SYNFill
(DDCMP Only)

2, 4, 6 SYNC Characters

6-15

INT1800,
INT7200,
EXT1800,
EXT7200,

INT2400,
INT9600,
EXT2400,
EXT9600.

6.5 SETTING SYSTEM OPTIONS
This section details each system option.
6.5.1 Name Option
The name option for a DFM unit is a cosmetic feature that appears
in quotes on all header lines. It provides a unique identity for
each DFM unit in a system.
The unit name can be set to any
combination of 16 alphanumeric characters.
The uni t name is part of the header line that appears wi th all
supervisory channel outputs. If a printing terminal is connected
to the supervisory channel, this option provides a way for the
information that is output to be stamped with the identity of the
unit:
4-28-84
6.5.2
Values:

12:15

DFM Series - ICP -11/78-8-

Level: 1.1

Type Option
MASTER, SLAVE

Default: MASTER
Before two DFM units can communicate, one must be named master and
the other slave.
This option is for identity purposes, and
combined with the configuration option (below), establishes a
working basis for down-line loading.
(See -Down-Line Loading", under configuration option, below).
6.5.3

Configuration Option

Values:

VALID, INVALID

Default: VALID
This option flags the entire set of parameters of one unit as
either valid or invalid. Invalid sets of parameters are replaced
by valid ones when down-line loading occurs.
DOWN-LINE LOADING OF OPERATING PARAMETERS
All parameters wi th the except ion of system type and name; 1 ink
speed; and date, time, and alarm are exchanged between units
. according to the following rules.
•

Parameters in units with an invalid configuration option
are replaced by those from a unit with a valid
configuration option. The invalid configuration option is
then changed to valid.

•

If parameters differ on two units, but the configuration
option of both is set to valid, then parameters from the
master unit replace those of the slave.

6-16

•

If both

units are invalid, master, or slave, the Device
Ready LED on both units blink until one unit is changed.
Data cannot be transmitted until this condition is
cleared.

Down-line loading of parameters ensures consistency of parameter
settings and also allows a DFM unit to be automatically
configured. When installing two units or adding a new unit to a
system, once parameters have been entered on one unit, the other
unit is automatically configured with the same parameters by
setting its configuration option to invalid. Before two units can
communicate, one unit must be set to slave, and proper link speed
must be selected for each unit.
Down-line loading occurs whenever the units are either reset or
reinitialized.
Units are reset whenever:
•

Power is applied to the unit

•

The power-up test is initiated, either via:
The TEST SYSTEM POWERUP command, or
The System Reset switch (SR)

units reinitialize whenever:
•

The current setting is changed for system
configuration, as well as link speed or delay.

type

•

The RESTART command is executed.

•

The link is lost for a period of at least one minute •

System reset involves the full set of power-up diagnostic tests.
System reinitialization is primarily a resynchronization of units.
Refer to Section 7.2 for a complete description of self-tests and
initialization procedures.
6.5.4
Values:

System Autodisconnect (AUTODISC) Option
~rom

1 to 255 minutes

Default: 20
The AUTODISC option has system and channel level settings. At the
SYSTEM level, a timeout period (in minutes) is defined.
switched
channels are automatically disconnected if there has been no data
activity within the defined timeout period.

6-17

At the channel level, the AUTODISC option applies to switched
channels and may be set to either enabled or disabled.
To
activate the switched channel AUTODISC timeout period, the channel
option must be set to enabled.
6.5.5
Values:

Switched-Data Parity (DATAPAR) Option
5, 6, 7, or a bits/character with parity of odd, even, or
none.

Defaul t: a-NONE
The switched-DATAPAR option selects data size and parity settings
for all swi tched channels.
This is done at the system level to
ensure that all dev ices connected to swi tched channels use the
same data/parity parameters.
6.5.6
Values:

Switched-Stopbits Option
1, 1. 5 , or 2

Default: 1
The number of stopbi ts for use on all swi tched channels is also
selected at the system level to ensure consistency.
Equipment
operating at 15~ bits/s or less generally requires 1.5 or 2
stopbits. For speeds above 15~ bits/s, 1 stopbit is sufficient.
6.5.7
Values:

Switched-Signals Option
ASSERT, PASS

Default: ASSERT
Refer to Section 6.7.1 for considerations of MEIA Signals on DFM
Channels".
This system level option allows the signals option
switched channels to be set to either assert or pass.

for

all

Each switched channel end also has a sign~ls option. The setting
at the channel level overrides the system level selection when it
is set to other than none.
At the channel level the defaul t is
none, which means that unless another value is entered, the system
level setting applies to the channel.
At the channel level, additional values of dial or dial* (the
asterisk is part of the selection and is NOT a reference to a
footnote) may be entered to allow the channel end to handle the
dial-up handshake with a connected modem.

6-18

With the assert value set, carrier, data set ready, and clear to
send are output continuously on the swi tched channel end.
Other
EIA signals are not passed between channel ends.
The DFM uni t
operates most efficiently when it does not have to relay EIA
signal changes between ends.
Assert is the recommended setting
unless there is a particular reason to relay EIA signals between
channel ends.
With the pass value, the DFM unit relays the toggling of EIA
signals between channel ends. This setting is recommended only in
the situation where it is important to see an EIA transition at
either end (that is, there is a special CPU function that is
associated with the toggling of an EIA signal) •
The signals option setting affects DFM operation when a modem is
connected to a channel end.
Refer to section 6.7.2 for more
information on how the channel signals option affects dial-up
operation.
6.5.8
Values:

Command Character (COMCHAR) Option
One or two characters -- any combination of hex values
from "" to IF.

Defaul t: ICIC
This option defines one or two characters that enable data
channels to enter command mode. When entered on a data terminal,
the supervisory command program is accessed, and supervisory
functions may be executed.
Hex IC corresponds to a control-backslash sequence on DIGITAL
terminals.
For non-DIGITAL terminals, ver i fy wh ich key sequence
corresponds to hex IC.
If IC is undesirable or not possible,
alter the COMCHAR for each data channel via the supervisory port.
The COMCHAR setting applies to async and switched channels only.
Synchronous and DDCMP channels cannot enter command mode.
When
the COMCHAR selection is entered on an enabled data channel, the
DFM responds with the command mode prompt. For the COMCHAR to be
recognized, however, COMTERM and COMECHO channel options must be
enabled on the selected data channel.
Table 6-3 1 ists val id command character (COMCHAR) selections and
what control key function is required.

6-19

EXAMPLES:

ASCII

HEX

ESC
ENQ
OC2

1B
fa5
12

CAUTION
Select a combination of one or two
characters that are NOT likely to be
transmitted as part of any data message
because it will inadvertently place the
channel in command mode.
Table 6-3

Command Character Selections

Key Pressed with
CTRL Key

Hex Code
Transmitted

Function
Mnemonic

Space Bar
A
8
C
0
E
F

fa fa
fa1
fa2
03
04
05
06
07
08
fa9
0A
0B
0C
00
0E
0F
10
11
12
13
14
15
16
17
18
19
1A
18
1C
10
IE
IF

NUL
SOH
STX
ETX
EOT
ENQ
ACK
BELL
BS
HT
LF
VT
FF
CR
SO
SI
OLE
DC1 or XON
OC2
DC3 or XOFF
OC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US

H
I
J

K
L
M

N
0

Q
R
S
T
U
V

W
X

Y
Z
[

\
]

6-2fa

6.5.9 Default Option
The SET SYSTEM DEFAULT <RETURN> command line sets all system,
channel, and link options to their default values.
The default
values for each programming option are shown in Table 6-4.
When channel type is changed to swi tched, synchronous, or DDCMP
for the first time, options for these channel types are at their
default values.
Table 6-4

Option Default Values

SYSTEM OPTIONS

DEFAULT

Name
Type
Configuration
Autodisconnect
SW-Data Parity (DATAPAR)
SW-Stopbi ts
SW-Signal s
Command Character (COMCHAR)

NONE
MASTER
VALID
20

a-NONE
1

ASSERT
lClC

LINK OPTIONS
Speed
Delay

SYNC
NORMAL

CHANNEL OPTIONS
ASYNC

Type
L-Speed
R-Speed
L-Flow
R-Flow
Data-Parity (DATA-PAR)
Stopbi ts
Signals
Fillcharacter
Priority
Echo
Messages
Command Terminal (COMTERM)
Command Echo (COMECHO)

1200
1200

NONE
NONE
a-NONE
1

ASSERT
ZERO
NORMAL
NONE
NONE
NONE
NONE

6-21

Table 6-4

Option Default Values (Cont)
DEFAULT

SWITCHED CHANNEL OPTIONS
Speed
Flow
Signals
Fill Character
Priority
Echo
Messages
Command Terminal (COMTERM)
Command Echo (COMECHO)
Channel ID
Group Access
Autodisconnect

1200
NONE
NONE
ZERO
NORMAL
DISABLED
DISABLED
DISABLED
DISABLED
A
A

DISABLED

DDCMP CHANNEL OPTIONS
Speed
Flow Control
Synfill Characters

EXT1200
NONE
6

SYNCHRONOUS CHANNEL OPTIONS
Speed
Flow Control
B10cksize

EXT1200
NONE
512

6.6 SETTING LINK OPTIONS
This section details each link option.
6.6.1

Link Speed Option

Values:

SYNC or ASYNC

Default: SYNC
Sync is the required setting for this option when the DFM unit is
connected to synchronous modems (either the integral modem module
or external synchronous modems). This setting permits link speeds
up to 19.2K bits/s to be clocked by the connected modem.
The async setting is required when the units are either directly
connected (using a BA22L cable) or connected via asynchronous
modems.
This setting allows the DFM unit to operate only at 9600
bits/s asynchronous (NRZI) speed (the DFM unit supplies the
clock) •

6-22

Link parameters are displayed wi th the SHOW LINK command.
When
set to sync, either the detected speed or the fact that wno clock w
has been detected is displayed. wNo clock w indicates that either
the DFM unit is not properly connected to the modem, or that the
modem is malfunctioning.
6.6.2
Values:

Link Delay Option
NORMAL or SATELLITE

Default: NORMAL
If the DFM network is to utilize a satellite link, this option
must be set to satellite. Satellite links have longer delay times
than normal land links. This must be expected by the DFM unit or
it will initiate retransmission of data that is not acknowledged
within the normal timeout period.
NOTE
A satellite link may not be used if a
DFM uni t containing software level 1."
is to be connected to a un i t wi th a
later software release.
6.7 IMPORTANT CHANNEL CONSIDERATIONS
Before describing channel options, it is important to discuss some
major factors associated with channel configuration. Channel
signals and flow control option settings, as well as considerations for connecting modems to DFM channels, merit particular
attention.
6.7.1 EIA Signals on DFM Channels
The setting for the channel signals option determines whether EIA
signals are asserted or relayed between channel ends.
Signals
should be asserted unless there is a particular reason why signals
must be relayed to the other channel end.
For asynchronous channels, setting the signals option to assert
causes the DFM unit to constantly assert CAR, DSR, and CTS to
devices connected to the channel. In addition to assert, switched
channels may be set to assert •• This causes CAR, DSR, and CTS to
be dropped briefly when a switching disconnection occurs.
If there is a special CPU function that is associated with a
change in EIA signals, it may be necessary to relay EIA signal
chang es from one end to the othe r.
Th i s i s accompl i shed by
setting the signals option to pass.
DIGITAL computers typically
do not have such special functions.
EIA signals are always asserted on synchronous channels.

6-23

6.7.2 Connecting Modems to DFM Channels
When a channel port is connected to a modem (either point-to-point
or dial-up) I a "crossover" cable must be used. Various types of
modems have d i ffe ren t strappi ng opt ions recommended fo r opt imum
performance when connected to a multiplexer. ChecK manufacturer's
documentation for additional installation requirements.
When dedicated (not dial-up) modems are used, the recommended
setting for the signals option is assert for asynchronous channels
and assert* for swi tched channels.
Synchronous channels do not
have a signals option; carrier, data set ready, and clear to send
are always asserted to devices connected to synchronous channels.
When dial-up modems are connected to either asynchronous or
switched channels, either the CPU or the DFM unit can manage the
dial-up handshake and establ ish communication wi th the connected
device. When the signals option is set to pass, EIA signals are
relayed between the modem and CPU and the computer handles the
handshake sequence.
The DFM unit works most efficiently when it handles the dial-up
handshake. This allows the unit to flush channel buffers and keep
track of channel status, as well as disconnect a switched channel
connection between DFM units when a hangup occurs.
For the DFM unit to manage the dial-up handshake on an
asynchronous channel, the signals option must be set to ei ther
R-dial or L-dial. These values correspond to either the local or
remote DFM unit, and indicate only a point of reference with
respect to the unit being programmed. For example, if programming
the local unit, and the remote unit is connected to the modem,
then R-dial is the appropriate setting. If the unit connected to
the modem is being programmed, then L-dial must be used. Only the
unit connected to the modem can handle the handshake sequence.
Switched channel ends may be set to either dial or dial* for the
DFM unit to handle the handshake with the connected dial-up modem.
Dial* permits a modem connected to a DFM channel to initiate an
outgoing call.
Since terminals connected via dial-up modems can transmit at any
speed up to that of the modems, terminal speed in dial-up
applications may be an uncertainty. The channel speed setting of
Wautobaud" allows the DFM unit to automatically adjust to the
speed of a connected terminal by sensing the data rate of the
first character received (expected to be a RETURN).
Autobaud may be utilized whether the DFM unit or the host computer
handles the dial-up handshake.

6-24

6.7.3 Flow Control on DFM Channels
The sum of the data rates of the external devices attached to a
DFM unit usually exceeds the data rate of the concentrated link.
Inherent in this situation is the possibility of buffer overflow
and the resultant data loss when heavy use occurs over an extended
period of time. Although the DFM unit can buffer bursts of heavy
traffic, sustained heavy loads can result in buffer overflow and
loss of data.
Buffer overflow is prevented (without increasing the speed of the
concentrated link) by the use of flow control.
DFM flow control
signals the connected terminal or CPU to stop sending data when
buffer space available for that channel approaches capacity. When
channel buffer space is available, a signal is issued to resume
sending data.
Terminal devices also stop and start the flow of data.
Flow
control is used most often by CRTs and printers that cannot
receive data as fast as the host computer can transmit it. If the
host computer is busy running a program, it may not be able to
accept data for a few moments and must also be able to control the
flow of data.
DFM flow control selections for channel ends must be set to a
convention that the connected device can recognize.
For
asynchronous and switched channels, local flow and remote .flow are
programmed independently and may be set to different values.
There are two basic types of flow control:
•
•

In-band
Out-of-band

The Rin-band" types work by inserting special characters into the
data stream (for example, X-ON X-OFF). This type of flow control
is generally used with all DIGITAL computers and terminals.
The Rout-of-band" types work by raising or lowering the voltage on
selected EIA pin connections.
This type of flow control is
primarily used with non-DIGITAL equipment.
Table 6-5 shows which category each of the DFM flow control
selections fit into.

6-25

Table 6-5

DFM Flow Control Selections

OUT-OF-BAND

IN-BAND

Async/Switched:

DSR-DTR
CTS-RTS
CTSH-RLSH
CTSH-RLSL
CTSL-RLSH
CTSL-RLSL

XON*-B
XON-B
Async/Switched Asymmetric:
XON*-C
XON*-T
XON-C
XON-T

Sync/DDCMP:
CTS-RTS

6.7.3.1 Out-of-Band Flow Control -- For DSR-DTR flow control, the
DFM unit raises DSR when data can be received, and expects to see
DTR high on a channel when the terminal can accept data.
CTS flow controls include CTS-RTS (for synchronous channels) and
CTS(x)-RLS(x) for asynchronous and switched channels.
For both
types, CTS is the signal output by the DFM uni t.
Wi th CTS-RTS,
the DFM unit raises CTS when data can be received, and expects the
synchronous device to have RTS raised when it can receive data.
CTS (x) -RLS (x) flow control types use CTS (clear to send) for the
DFM unit to signal terminals and RLS (reverse carrier) for
terminals to signal the DFM unit.
CTS(x)-RLS(x) flow control names define the send data (as opposed
to stop data) conventions. For example, CTSH-RLSH indicates that
the DFM unit has CTS high when data can be received (thus lower it
for data to be stopped), and expects the terminal will have
reverse carrier high when it can receive data.
CTSH-RLSL
indicates that the DFM unit has CTS high when data can be
received, and expects the terminal to have RLS low when it can
receive data.
The total CTS(x)-RLS(x) set of flow controls consists of:
CTSH-RLSH
CTSL-RLSH

CTSH-RLSL
CTSL-RLSL

Appendix E covers the pin assignments for each of the EIA signals,
for the link as well as DFM channels.

6-26

6.7.3.2 In-Band Flow Control -- The XON-B type flow control must
be set the same for both ends.
XON-B type flow control may be
used with switched or asynchronous channels connected either to a
terminal or computer port.
This type of flow control is
sufficient for most applications.
XON-B causes the DFM unit to
act on received XON and XOFF characters from channel devices.
XON-B type flow control generates XON and XOFF characters to
channel devices when appropriate.
The XON-C and XON-T flow controls are used when it is necessary to
have different flow control settings for terminal and computer
channel ends.
The ·C· denotes connections to computers and the
·T· is for connections to terminals. These types of flow controls
should be used only as required by the manufacturer's recommendations. The matrix chart of Table 6-6 shows when certain types of
flow controls would be used with what types of equipment.
With XON-C, the DFM unit generates an XON or XOFF to the computer,
but does not respond to either of these characters coming from the
computer.
With XON-T, the DFM unit does not send an XON or XOFF to the
terminal device, but acts on these characters when received from
the terminal device.
All XON flow control types send a DCl (11 hex) for XON and a DC3
(13 hex) for XOFF.
The XON* type of flow control provides periodically an automatic
transmission of XON to "prompt" the attached device in case it
missed an initial XON. The XON* flow control also provides an
automatic retransmission of XOFF after the initial XON if it
continues to receive data.
Note that XON* selections are NOT desirable in some applications.
Problems may occur in applications where a channel device either
autobauds on the first character received (expected to be a CR) or
initiates other functions, expecting data to immediately follow an
XON.

6-27

Table 6-6

DFM Flow Control Selection Chart

Channel
Type

Terminal End
Devices*

Terminal End
Selection

DIGITAL Computer
End Selection

Asynchronous
or
Switched

DIGITAL
Asynchronous
Terminals

XON-B or
XON*-B

DIGITAL Personal
Computers
Emulating a
Terminal

XON-B or
XON*-B

DIGITAL
Serial
Printers

XON-T

XON-C

Dial-Up
Asynchronous
Modems

XON-B

Tektronics
Type
Terminals

CTS-RTS

XON-B

Synchronous
Terminals

CTS-RTS

Synchronous

* The DFM uni t supports flow control for all DIGITAL computers
acting as CPU end devices.
For non-DIGITAL computers and
terminals, see manufacturer's specifications.

6.8 SETTING CHANNEL OPTIONS
Each channel type has a unique set of other options.
After
channel types are explained below, options for each type of
channel are explained separately beginning with Section 6.8.2.
6.8.1
Values:

Channel Type Option
ASYNCHRONOUS, SWITCHED, SYNCHRONOUS, DDCMP, or UNUSED.

Default: ASYNCHRONOUS

6-28

The channel type option is used to program the DFM unit to support
the communications protocol of devices connected to the selected
channel. When a channel is changed from one type to another,
execution of a RESTART command is recommended.
•

Asynchronous Channels -- Asynchronous channels operate
wi th asynchronous protocol, and are ded icated.
That is,
a dev ice connected to Channel I on the local uni t can
only communicate wi th whatever device is connected to
Channel I on the remote unit.

•

Switched Channels
Switched channels operate with
asynchronous protocol, but can be connected to any other
swi tched channel (via the CONNECT command, see Chapter
5) •
Swi tched channel ends are completely independent.
Channel I on the local unit may be connected to any other
channel on the local unit, as well as any channel on the
remote unit.
(See Channel ID/Group Access options;
Section 6.8. 3.10) •
The switched channel contention feature allows a limited
number of computer ports or other terminal facilities to
be shared among a variety of users.
This enables, for
example, a l6-channel unit to be connected to a unit with
f e we r po r t s •
Channel contention operates on a first come, first served
basis. For example, suppose Channell on the local unit
is to be connected to Channel 3 on the remote uni t.
If
Channel 3 on the remote unit is already connected to
another switched channel, the request is queued.
If the
request from Channel I is the first one queued, it will
be connected as soon as the current connection on Channel
3 is terminated.
Otherwise, it must wait until prior
requests for connection are satisfied.

•

Synchronous Channels -- Synchronous channels are defined
as ei ther DDCMP or synchronous channel types.
DDCMP is
Digital Equipment Corporation's proprietary protocol used
wi th systems jo ined by DECnet fac il i ties.
Synchronous
channel
types
support
any
type
of
synchronous
communications protocol in a transparent manner.
That
is, the DFM unit does not look at or interpret data on
the channel.
In the absence of CTS-RTS flow control, synchronous
channels operate full-duplex.
CTS-RTS flow control
selects half-duplex operation.

6-29

Since constant communication between devices is a part of
most synchronous protocols, synchronous channels have a
big impact on link utilization.
Data rate calculations
for the link must include 120% of the combined data rates
for full-duplex synchronous channels.
For DDCMP and
half-duplex synchronous operation, the link calculations
must include 50% of aggregate input.
Half-duplex operation is recommended whenever possible
for synchronous (non-DDCMP) channel types. Half-duplex
operation is selected by CTS-RTS flow control.
DFM handl ing of the DDCMP protocol el iminates the need
for flow control or half-duplex operation.
In DDCMP
protocol, when the DFM unit detects an idle frame (no
data present), it does not transmit it across the link.
This saves concentrated link bandwidth for frames with
data.
The maximum blocksize that can be handled by the
DFM unit on DDCMP channels is 4K bytes. For optimum
per fo rmance,
the DECnet set ting of
576 bytes
is
recommended.
Synchronous channel load must be spread evenly among
channel modules. The DFM unit can support synchronous or
DDCMP operation only on two channels out of every four
channel group (Channels 1 and 2, 5 and 6, 9 and 10, and
13 and 14). The load should still be spread as evenly as
possible among these channels.
For example, if 3
synchronous channels are required on a 12-channel unit,
they should be assigned to Channels 1, 5, and 9.
Synchronous communications protocols typically include
their own error detection and retransmission schemes.
The DFM unit does not provide error correction on
synchronous and DDCMP channel types.
Section 2.4.2 covers link speed calculations,
synchronous channel considerations.
•

including

·Unused· Channels -- Channels not currently in use may be
set to a channel type called unused.
This prevents the
channel from being serviced by the DFM unit, reduces
system overhead, and improves serv ice to the remaining
channels. Channels may be changed from one of the other
types to unused, and then back again, without losing
original parameter settings.

6-30

6.8.2

Asynchronous Channel Options

6.8.2.1 Asynchronous Speed -- Asynchronous channel speed is set
independently for either end with L-speed (local) and R-speed
(remote) options.
Values:

50, 75, 110, 134.5, 150, 390, 699, 1299, 249~, 4899,Split-Speeds:
1299/75,
9600,
Autobaud,
Samebaud.
75/1200, 2400/15~, 15~/24~~

Defaul t:

1200

With the autobaud value, the OFM unit senses the speed of the
first received character (expected to be a RETURN) and sets
channel speed to the appropr iate val ue. Da ta rates of 159, 399,
6~~, 1200, 24~~, 48~0, and 960~ bits/s can be sensed by autobaud.
The split-speed values allow a terminal to transmit and receive at
different speeds.
For example, the 75/12~0 value sets the
transmit speed to 75 bits/s and the receive speed to l2~0 bits/s.
Transmit speed is the first number in all split-speed values.
A
split-speed value at one end of a channel does not affect the
speed setting for the other end.
The samebaud value for the speed option sets the speed of an
asynchronous channel end to match the speed of the other end of
the channel; it is usually (but not necessarily)
used in
conjunction with autobaud. The samebaud value can be used only at
one end of an asynchronous channel.
6.8.2.2

Asynchronous Flow Control --

Values:

NONE, OSR-OTR, CTS-RTS, CTSH-RLSH, CTSH-RLSL CTSL-RLSH,
CTSL-RLSL, XON*-B, XON*-C, XON*-T, XON-B, XON-C, XON-T

Oefault: NONE
Considerations for channel flow control settings are covered
Section 6.7.3.
6.8.2.3

Asynchronous Data Parity

Values:

8-NONE, 8-EVEN, 8-000, 7-NONE, 7-EVEN,
6-EVEN, 6-000, 5-NONE, 5-EVEN, 5-000.

7-000,

6-NONE,

Default: 8-NONE
Both character size and the type of parity used are selected with
this option. The general format is n-NONE, n-EVEN, or n-OOO where
n is the number of data bits in the character with even, odd, or
no parity bit attached.

6-31

6.8.2.4

Asynchronous Stopbits --

Values:

1, 1.5, 2

Default: 1
The stopbits option selects the number of stopbits used in
asynchronous communication. Equipment operating at 159 bits/s or
less normally use 1.5 or 2 stopbits.
For equipment operating at
higher speeds, 1 stopbit is sufficient.
6.8.2.5

Asynchronous Signals --

Values:

ASSERT, PASS, L-DIAL, R-DIAL, 2-DIAL

Default: ASSERT
NOTE
dial-up
or
When
a
modem
(either
dedicated)
is
connected
to
a
DFM
channel, a crossover cable (BC22M) must
be used.
Refer to Section 6.7.1 for considerations of "EIA Signals on DFM
Channels".
•

ASSERT -- Carrier, data set ready, and clear to send are
asserted continuously by the DFM unit. Other EIA signals
are not relayed between channel ends.
The DFM system
operates most efficiently when it does not have to relay
EIA signal changes.
Assert is the recommended setting
unless a dial-up modem is connected to the channel (see
the dial values, below), or there is some other CPU
function associated with EIA signal changes.

•

PASS -- With the pass value, the DFM unit relays the
toggling of all EIA signals between channel ends.
This
setting is recommended only in the situation where it is
important to see an EIA transition at one end or the
other.
This is generally the case only if the host
computer has a spec ial function assoc iated wi th an EIA
signal transition, or if the operator wants the host
computer to handle the dial-up handshake wi th a modem
connected to a DFM channel.

•

L-DIAL, R-DIAL, 2-DIAL -- These val ues enable the DFM
unit to handle the dial-up handshake when an asynchronous
channel is connected to a dial-up modem.
"L"," R", and
"2" correspond to the local, remote, or both ends of an
asynchronous channel.
This option must be set to the
value that corresponds to the unit that is connected to
the modem.

6-32

For example, if connected to the supervisory channel on
the local unit, and the remote unit is connected to a
dial-up modem, signals must be set to R-dial. If you are
on the supervisory channel of the unit that is connected
to the modem, the L-dial value is used.
2-dial is used
in the event that both ends of an asynchronous channel
are connected to dial-up modems.
Refer to Section 6.7.2 for more information on ·Connecting Modems
to DFM Channels".
6.8.2.6

Asynchronous Fillcharacter --

Values:

0 to 255

Default: 2
The fillcharacter option defines the number of null characters
that are transmitted after a RETURN, before the DFM unit sends the
next valid data.
Null characters following a RETURN provide a time period for the
cursor or the print head on terminal devices to return to the
starting point for the next line. Some of the older CRTs and
printers require such a pause to prevent data loss between lines
or page advances.
For the majority of newer devices, this option may be set to 0.
6.8.2.7

Asynchronous priority

Values:

NORMAL, HIGH, LOW

Default: NORMAL
Channel settings for priority take effect only when the concentrated link between DFM units is backed up, that is, data is
buffered and waiting to be sent across the link.
Each setting corresponds to the size of the frame (therefore, the
amount of data) that can be sent at each channel's opportuni ty.
Normal channel pr ior i ty throughput is about three times that of
low priority channels; high priority channels have about four
times the throughput of low priority channels. A priority setting
of "low" reduces link efficiency.

6-33

6.8.2.8

Asynchronous Echo --

Values:

NONE, L-UNIT, R-UNIT or BOTH

Default: NONE
The ECHO option enables either the local, remote, or both DFM
uni ts to echo data characters back to terminals rather than the
host computer.
In some appl ications (that is, when a satell i te
1 ink is used) it is desirable to let the DFM uni t do the echoing
because of the additional delay involved with CPU echo.
The general rule is to let the computer do the echoing of
characters which assures that it is receiving the data.
If both
the CPU and DFM unit echo the character, it appears twice on the
terminal screen.
6.8.2.9

Asynchronous Messages --

Values:

LOCAL, REMOTE, BOTH, or NONE

Default: NONE
This option allows neither, either, or both ends of a channel to
receive automatic system error messages, or messages that are
broadcast from a command channel.
CAUTION
Error and broadcast messages must NOT be
sent out on channel ends connected to
intell igent dev ices.
Unsol ic i ted input
to the host computer, personal computers, or intelligent terminals may cause
problems.
Table 6-7 is a list of automatic system alarm messages and their
meanings.
Table 6-7

Alarm Messages

<188>**CONCENTRATED LINK JUST WENT DOWN
Link communication is interrupted, initialization to follow.
<189>**CONCENTRATED LINK IS DOWN
Notification to the dial-in user that the link is currently
inoperable.
<118>**CONCENTRATED LINK NETWORK-READY PROBLEM
One of the following has occurred:
no CTS on the 1 ink, no data
received on the link, or transmit retries are failing.
Also, NR
LED blinks; Table 3-3 describes each problem.
(289)**MUX LOST DATA TO TERMINAL:FRAMING ERR
A framing error on an output character has occurred.

6-34

Table 6-7

Alarm Messages (Cont)

<29l>**MUX LOST DATA TO TERMINAL:PARITY
A parity error occurred.
<292>**LOST DATA TO TERMINAL:BUF OVFL
One or more output characters are lost due to buffer overflow.
<293>**MUX LOST DATA TO TERMINAL:OVERRUN
One or more output characters are lost due to data overrun.
<294>**MUX LOST DATA FROM TERMINAL:FRAMING ERR
A framing error on an input character has occurred.
<29S>**MUX LOST DATA FROM TERMINAL:PARITY
A parity error on an input character has occurred.
<296>**MUX LOST DATA FROM TERMINAL:BUF OVFL
One or more input characters are lost due to buffer overflow.
<297>**MUX LOST DATA FROM TERMINAL:OVERRUN
One or more input characters are lost due to data overrun.
<39l>**PARAMETER STORAGE FAILURE
Parameter protect PP switch feature is engaged.
<392>**ERROR IN COMMAND, 'text-of-command': 'kind-of error'
The 'text-of-command' displays the incorrect command sent.
The 'k i n d - a f - err 0 rid i s pIa y son e oft h r e e po s sib 1 e me s sag e s i
"Locked" when the Parameter Protect switch is IN, "Conflict" when
the attempted command is incompatible with current configuration,
and "Value" when the value selected is not accept~ble.
<3ll>**SYSTEM DEVICE-READY PROBLEM
One of the following is occurring: The NVROM is bad or disabled,
or both units are invalid, masters, or slaves.
Also, DR LED
blinks; see Table 3-3.
6.8.2.19

Asynchronous Command Terminal (COMTERM) --

Values:

LOCAL, REMOTE, BOTH, or NONE

Default: NONE
The COMTERM option enables a channel end to enter command mode.
Unless it is enabled for the appropriate channel end, command
character (COMCHAR)
is not "recognized when entered on the
terminal. (Refer to the system option of COMCHAR.)

6-35

6.8.2.11

Asynchronous Command Echo (COMECHO)

Values:

NONE, LOCAL, REMOTE, or BOTH

Default: NONE
This option enables the DFM unit to echo supervisory commands that
are entered on a data channel so that they appear on the terminal
screen.
DFM echoing is not normally used for channels in data
mode, but is necessary for input to the supervisory command
handler. Self-echoing terminals do not need to use this option.
6.8.3 Switched Channel Options
Switched channel options are set separately for each channel end.
Switched channel data parity and stopbits options are set at the
system level to ensure that all switched channel devices use the
same data, parity, and stopbit parameters.
The signals option for all switched channels may be set
simul taneously to ei ther assert or pass under the system level
option of SW-signals.
Each swi tched channel also has a signals
option that overr ides the setting at the system level.
At the
channel level, additional values of dial and dial* may be entered
to allow the channel end to handle the dial-up handshake wi th a
connected modem.
If the signals option at the channel level is
left at the default value of NONE, the setting for the system
SW-signals option takes effect.
6.8.3.1

Switched Speed --

Val ue s :

5 ~, 75, 11 ~, 134. 5 ,
960~,
Autobaud.
24~0/15~, 150/24~~

Defaul t:

12~0

15 ~, 3 ~ ~, 6 ~ ~, 12 ~ ~ , 2 4 ~ ~, 4 8 ~ 0 ,
Split-Speeds:
1200/75,
75/1200,

The autobaud value is useful when a channel end is connected to a
dial-up modem.
The DFM unit senses the speed of the first
received character (usually a RETURN) and sets channel end speed
to the same value. Data rates of 150, 300, 600, 1200, 2400, 4800,
and 9600 bits/s can be sensed when the autobaud value is in
effect.
The split-speed values allow terminals to transmit and receive at
different speeds.
For example, the 75/1200 value sets the
transmit speed to 75 bits/s and the receive speed to 1200 bits/s.
Transmit speed is the first number in all split-speed values.
A
split-speed value at one end of a channel does not affect the
speed setting for the other end.

6-36

6.8.3.2

Switched Flow Control --

Values:

NONE, DSR-DTR, CTS-RTS, CTSH-RLSH, CTSH-RLSL, CTSL-RLSH,
CTSL-RLSL, XON*-B, XON*-C, XON*-T, XON-B, XON-C, XON-T

Default: NONE
Considerations for channel flow control settings are covered
Section 6.7.3.
6.8.3.3

Switched Signals --

Values:

NONE, PASS, ASSERT, ASSERT*, DIAL, DIAL*

Default: NONE
NOTE
Whenever a DFM port is connected to a
modem (either dial-up or dedicated), a
crossover cable (BC22M) must be used.
•

NONE -- Outgoing signals are either passed or asserted,
based on the value of the system SW-signals option.

•

ASSERT -- The DFM unit outputs carrier, data set ready,
and clear to send continuously on the switched channel
end.
Other EIA signals are not passed between channel
ends of a swi tched connection.
The DFM uni t operates
most efficiently when it does not have to relay EIA
signal changes between ends. Assert is the recommended
setting unless there is a particular reason to relay EIA
signals between channel ends.

•

PASS -- The DFM unit relays the toggling of EIA signals
between channel ends.
This setting is recommended only
in the situation where it is important to see an EIA
transition at either end (for example, there is a special
CPU function that is associated with the toggling of an
EIA signal, or if an operator wishes the CPU to handle
the handshake with a dial-up modem connected to a remote
DFM channel) •

•

ASSERT* -- Carrier, data set ready, and clear to send are
always
asserted,
except
when
a
switched
channel
connection between DFM units is terminated.
When the
disconnect occurs, these signals are dropped at both
channel ends for four seconds.
This feature can be
utili zed to cause a logoff on the CPU when a swi tched
connection is terminated.

6-37

Also, in this mode, DTR is monitored.
When DTR is
dropped by the terminal or CPU at either end of a
switched connection, the switched connection between
units is terminated.
Many CPU types can be set to lower
DTR momentarily when a logout occurs.
(On a VAX CPU, the
SET TERM/MODEM/HANGUP command causes DTR to be dropped
briefly on logout.)
This can be useful in applications where the DFM unit is
used to contend for CPU ports or other resources.
Since
a logoff by a user disconnects the swi tched connection
between DFM units, the resource connected to the DFM
channel is released for use by another person.
A
terminal or personal computer also drops DTR when it is
turned OFF, so this automatically terminates a swi tched
connection.
•

DIAL -- This value allows the DFM unit to perform the
dial-up handshake with a connected modem, enabling the
modem to answer a call when ring indicator is seen.

•

DIAL*-- Dial· allows an outgoing call to be initiated by
a modem that is connected to a DFM channel. If a modem
with an autodial feature is used, dial* allows communications to be initiated by either a ring indicator on the
modem (incoming call) or by connecting to the dial*
channel from another swi tched channel (outgoing call).
For incoming calls, the modem handshake is handled just
as it is with the dial setting.
Connecting to a dial*
channel from anothe r swi tched channel, however, causes
DTR and RTS to be raised, which puts the modem on-line.
Now, the modem can be instructed to dial an outgoing
call. When a call is successful, and communication is
established with another modem, the modem raises DSR and
CAR.
The DFM uni t moni tors these signals, and if they
drop for more than five seconds (indicating that the
modem has stopped communicating wi th the other modem),
the switched connection is terminated and DTR and RTS are
dropped, forcing the modem off-line.
If the modem is communicating with another modem, and the
switched connection is terminated, the DFM unit drops RTS
and DTR, which causes the modem to go off-line (hang up
the phone 1 ine) •
Al though a channel speed setting of autobaud can be set
on a dial. channel, it is not recommended because on an
outgoing call autobaud cannot take place, and channel
speed will be undetermined.
Additional information on EIA signal characteristics in
dial, dial*, and assert* modes is found in Appendix E.

6-38

RECOMMENDED SETTINGS FOR THE SIGNALS OPTION ON SWITCHED CHANNELS
The pass setting does not provide any of the DFM functions that
are associated with the other settings of the signals option (for
example, automatic logout at the CPU or automatic disconnection of
a swi tching connection).
For this reason, the pass setting is
recommended only in applications where there is either a special
CPU function associated with the toggling of an EIA signal, or an
operator wishes the CPU to handle the dial-up handshake with a
modem connected to the DFM unit.
When a swi tched channel end is connected to a DIGITAL CPU, (and
especially when the DFM unit is used to contend for channel
resources), the channel should be set to assert·. Only assert*
provides automatic termination of switched channel connections
upon logoff, as well as automatic logoff from the CPU upon
disconnection of a switched channel connection.
When connected to a terminal or personal computer, the signals
option may be set to either assert or assert·.
Only assert*
causes a swi tched
channel
connection
to
be
automatically
terminated when the terminal device is powered off. This in turn
causes a logoff at the CPU.
When a switched channel end is connected to a modem with dial-out
capabilities, it must be set to dial· to initiate an outgoing
call. This setting also provides automatic hang-up on a switched
channel disconnection, as well as automatic switched channel
disconnection upon modem hang-up.
If dialing into a channel set
to dial*, only one switched connection can be made per phone call.
This is because when the swi tched connection is terminated, the
modem is forced off-line.
When connected to a modem that does not have dial-out capabil ities, use the dial setting. This setting provides automatic
disconnection upon hang-up, but the modem does not hang up the
phone line when a switched channel connection is terminated.
6.8.3.4

Switched Fillcharacter --

Values:

0 to 255

Default: Zero
The fillcharacter option defines the number of null characters to
be transmitted following a RETURN.
Null characters following a RETURN provide a time period for the
cursor or the print head on terminal devices to return to the
starting point for the next line. Some of the older CRTs and
printers require such a pause to prevent data loss between lines
or page advances.
For the majority of newer devices, this option may be set to 0.

6-39

6.8.3.5

Switched Priority

Values:

NORMAL, HIGH, LOW

Default: NORMAL
Channel settings for priority take effect only when the concentrated link between DFM units is backed up, that is, data is
buffered and waiting to be sent across the link.
The various settings correspond to the size of the frame
(therefore, the amount of data) that can be sent at each channel's
opportuni ty. Normal channel pr ior i ty throughput is about three
times that of low priority channels; high priority channels have
about four times the throughput of low priority channels. A
priority setting of wloww reduces link efficiency.
6.8.3.6

Switched Echo --

Values:

ENABLED, DISABLED

Default: DISABLED
When enabled, the echo option instructs the local DFM unit to echo
data characters back to terminals. In some applications (that is,
when a satellite link is used) it is desirable to let the DFM unit
do the echoing because of the additional delay involved with CPU
echo.
The general rule is to let the computer do the echoing' of
characters which assures that it is receiving the data. If both
the CPU and DFM unit echo the character, it appears twice on the
terminal screen.
6.8.3.7

Switched Messages

Values:

ENABLED, DISABLED

Default: DISABLED
This option enables a channel device to receive automatic system
error messages, or messages that are broadcast from a command
channel.
CAUTION
Error and broadcast messages must NOT be
sent out on channel ends connected to
intelligent devices. Unsolicited input
to the host computer, personal computers, or intelligent terminals may cause
problems.
A list of alarm messages and their meanings is listed
6-7.

6-49

in Table

6.8.3.8

Switched Command Terminal (COMTERM) --

Values:

ENABLED, DISABLED

Default: DISABLED
The COMTERM option enables a channel end to enter command mode.
Unless this option is set enabled for a particular channel, the
command character sequence (COMCHAR)
is not recognized when
entered on the terminal, and the data channel cannot enter command
mode.
CAUTION
Select a combination of one or two
characters that are NOT likely to be
transmitted as part of any data message
because it will inadvertently place the
channel in command mode.
6.8.3.9

Switched Command Echo (COMECHO)

values:

ENABLED, DISABLED

Default: DISABLED
This option allows the DFM unit to echo commands so that they
appear on the terminal screen as they are entered. DFM echoing is
not normally used for channels in data mode, but is necessary for
input to the supervisory command handler.
Self-echoing terminals
do not need to use this option.
6.8.3.1~

10 Values:

Switched Channel ID/Group Access
Any single letter.

Group Access Values: Any combination of channel IDs.
Default (for both): A
Switched channel ends are assigned a channel 10, which is a
letter, and a group access value, which is a combination of other
channel IDs.
The group access value for a channel specifies the
IDs of other channels that it can be connected to. A "group" is
formed when more than one channel end is assigned the same ID.
For example, suppose the local end of Channel 1 has a channel 10
of C and a group access of AXY. This means that it can be
connected only to channels that have an 10 of A, X, or Y. Other
channels wishing to connect to the local end of Channel 1 must
have the letter C in their group access values.

6-41

·A" is the default setting for both the 10 and group access
options for all swi tched channels. This means that any swi tched
channel can be connected to any other channel because they are all
in the same group.
A group is formed by assigning the same 10 (letter) to more than
one channel end. It is appropriate, therefore, to assign the same
IO to all channels that access the same facilities. For example,
assume four channel ends are connected to a microcomputer that
contains all the accounting information. If only these four
channel ends are assigned to group A, then whenever a user needs
to access accounting information, all that needs to be entered is
·CONNECT A". If all channels in group A are busy, the request is
queued until anyone of the channels is disconnected.
In the above example, the channel end that wishes to be connected
to group A must have the letter A in its group access assignment
or the connection will be denied. In this way, groups of channels
that are connected to certain facilities are protected from being
accessed by an unauthorized user.
Each group can also be assigned a "name", which is a fivecharacter descriptive title for the group (for example, A =
ACCTG). Group names are assigned with the SET command.
They are
useful because the OFM unit prompts with group lOs and names (for
identification purposes) when a CONNECT command is entered.
EXAMPLE 6-4: SETTING GROUP IO/ACCESS
Command Input: SYS> set chann 1 local id b <RETURN>
Unit Response: Parameter Saved.
Command Input: SYS> set channell local groupaccess abc <RETURN>
Unit Response: Parameter Saved.
Local Channell can now access any other switched channel that has
an 10 of A, S, or C.
For any other channel to access local
Channell, the letter S must appear in its group access
assignment.
In Example 6-5, a group is defined by setting the lOs of several
channel ends to the same value. The group is then assigned a name,
and the use of the name is illustrated.

6-42

EXAMPLE 6-5: ASSIGNING GROUP NAME
Command Input: SYS> set channell local id e <RETURN>
Unit Response: Parameter Saved.
Command Input: SYS> set channel 2 local id e <RETURN>
Unit Response: Parameter Saved.
Command Input: SYS> set group e eng-l <RETURN>
Unit Response: Parameter Saved.
Channels 1 and 2 are now in group E, and the group has been
ass igned the name n ENG-I" (that is, "eng ineer ing one").
Group
names are listed when:
•

A CONNECT command, followed by a RETURN is entered on a
switched channel in command mode:
SEL> connect <RETURN>
Valid Entries: <A to Z> <1 - 16> (or

Ay)

A = ACCTG
E = ENG-l
•

From the supervisory channel, a CONNECT command
completed:
SYS> connect 1 local <RETURN>
Valid Entries: <A to Z> <1 - 16> (or

is not

Ay)

A = ACCTG
E = ENG-1
•

A SHOW GROUP command is entered on a supervisory channel:
SYS> show group <RETURN>
Current Group Names are:
A = ACCTG
E = ENG-1

6-43

6.8.3.11

Switched Automatic Disconnect (AUTODISC) --

Values:

ENABLED or DISABLED

Default: DISABLED
When enabled for a switched channel end, this option permits the
current swi tched connection to be automatically disconnected if
there has been no activity for a specified time period.
The
timeout period is the same for all switched channels, and is
defined by the system level AUTODISC option.
6.8.4 Synchronous and DDCMP Channel Options
There are three types of synchronous channel operation:
•
•
•

Synchronous CTS-RTS Mode
Synchronous Bandsplit Mode
DDCMP Mode

"Synchronous" channel types can support any type of synchronous
protocol. With CTS-RTS flow control, synchronous channels operate
in half-duplex mode.
When no flow control is selected for a synchronous channel,
operates in full-duplex "bandsplit" mode.

"DDCMP" channel types support Digital Equipment Corporation's
propr ietary synchronous protocol
(DDCMP), used pr imar ily by
systems connected wi th DECnet fac il i ties.
The max imwn blocksi ze
tha't can be handled by the DFM uni t on DDCMP channels is 4K bytes.
For optimum performance, a blocksize of 576 bytes (as a DECnet
parameter) is recommended.
Synchronous channel types have a large impact on the determination
of link speed. For information on this and other important
synchronous channel considerations,
refer to Section 6.8.1
(channel type option) •
6.8.4.1 Synchronous Speed -- Speed is set independently for
either end of synchrono us channels wi th L-speed and R-speed
options.
Values:

INT1200, INT1800, INT2400, INT4800, INT7200, INT9600,
EXT1200, EXT1800, EXT2400, EXT4800, EXT7200, EXT9600

Default:

EXT1200

INT and EXT preceding each speed indicate either internal or
external clocking.
External settings are for synchronous or DOCMP channels connected
to modems or self-clocking terminals. Indicate the speed of the
device that is to be connected.

6-44

With internal speed settings, the DFM unit provides clocking for
the channel. When terminals wi thout sel f-clocking are connected
directly to the DFM unit, channel speed must be clocked by the DFM
unit.
6.8.4.2

Synchronous Flow Control --

Values:

NONE, CTS-RTS

Default: NONE
CTS-RTS flow control for a synchronous channel selects half-duplex
(one direction at a time) operation.
Due to link bandwldth
considerations, half-duplex operation for synchronous channels is
recommended whenever possible.
Refer to Section 6.8.1 (channel type option) for more information
on link speed and other considerations for synchronous channels.
6.8.4.3 Synchronous Blocksize -- This option applies to non-DDCMP
channels only.
Values:

512, 1024, 2048, 4096

Default: 512
This option informs the DFM unit of the size of data blocks to be
used by the synchronous protocol on the selected channel.
6.8.4.4

Synchronous SYNFILL -- Applies to DDCMP channels only.

Values:

2, 4, or 6

Default: 6
This option selects the number of sync characters that will
precede each block of data transmitted on DDCMP channels. The
recommended setting is 6.

6-45

CHAPTER 7
TROUBLESHOOTING
AND TESTING

7.1 GENERAL
This chapter provides a systematic approach of using the various
test features of the DFM uni t and associated modems to isolate
problems with the hardware or telephone facilities.
The DFM unit provides two commands (see Chapter 5) to aid in the
troubleshooting process:
•

The MONITOR command is available to provide a variety of
statistics concerning system, channel, and link conditions.
From these statistics and reports, certain decisions can be
made as to the next logical step or corrective action.

•

The TEST command is provided to allow a variety of channel
and link tests to determine if data transmissions are clean
or contain errors.

The DFM unit also has two maintenance pushbutton switches located
on the control module. These switches allow a limited set of tests
to be executed manually should the supervisory channel be
unavailable or inoperative.
See Table 3-2 for a description of
the use of these two switches.
Refer to Tables 3-6 and 3-7 for
descriptions of modem controls and indicators.
There are a number of places in a communications system where a
problem can occur that will either cause numerous errors (SA
and/or RA LEOs on control module blinking frequently) or cause
communication to fail entirely (NR LED not ON). Problems occur
when:
•

One of the modem modules may be malfunctioning.

•

One of the control modules may be malfunctioning.

•

The qual i ty of the telephone I ine connecting the uni ts
may have degraded.

•

There may be an incompatibility in
parameters of the two units (that is,
system type).

the operating
I ink speed 0 r

When experiencing trouble with the system (numerous errors or the
NR LED not ON), make sure that no switches are IN except for those
that control modem speed (high speed or fallback).

7-1

Next, check the CD LEDs. There are two on each uni t; one on the
modem module and one on the control module. If none of the CD LEDs
are ON, the fault is most likely in one of the modems or in the
telephone line (refer to the section 7.4.1).
If the control module CD is not ON in one unit, the fault is most
likely in that DFM unit).
Basically, troubleshooting the DFM unit can be divided into two
areas; channel and link.
Channel considerations are:
•

DFM channel input/output (I/O) circuits

•

Channel cables and connections

•

Channel devices (terminals, CPUs, printers, modems, and so
forth)

Link considerations are:
•

DFM link I/O circuits

•

Link modes (integral and standalone)

•

Link cables and connections

•

Telephone lines

Whenever a problem is experienced, it is very important to
document all of the circumstances and symptoms concerning the
problem.
If it should become necessary to consult with a DIGITAL
Field Eng ineer, a history of the type and sequence of problems
experienced allows Field Service personnel to get a better idea of
where to begin.
7.2 AUTOMATIC SELF-TESTS
Automatic self-tests check hardware components that are not a part
of the channel or link circuits. Special LED error codes identify
the failure and location.
DFM self-testing occurs whenever the units are either "reset" or
"reinitialized".
Units are reset when:
•

Power is applied to the unit,

•

The TEST SYSTEM POWERUP command is issued, or

•

The System Reset switch (SR) is pressed.

7-2

units are reinitialized when:
•

The current setting for system type or configuration, as
well as link speed or delay, is changed, or

•

The RESTART command is executed, or

•

The link is lost for a period of greater than one minute.

System reset executes the full self-test diagnostic. All buffers
are cleared, all counters set back to zero, and the logon state of
the supervisory channel is cleared (it is necessary to log back
onto the supervisory channel).
System reinitialization is primarily a resynchronization of units
and executes only a limited set of self-test diagnostics. Channel
counters and buffers are cleared, but link counters and the
supervisory channel logon state are retained.
Down-line loading of channel parameters occurs with both system
reset and reinitialization.
When reset and reinitialization are
complete, control module LEOs indicate system status.
The following is a summary of initial system conditions and LED
status associated with the self-test.
Disregard modem indicators
during self-test. Modem indicators are only significant in LBACK
testing.

7-3

Control Module LED Status

Condition

DFM does
self-test I

DFM passes self-te(!j
link not connected 2

•

DFM units connected,
link not operational 0)

DFM units connec~,
link operational 4

• •

(!) pass

•

Legend
X

Don't Care (ON or OFF)

OFF

•

Blinking

NOTES

CD Refer to Section 7.3 for additional LED status indications.
If a cable is installed to either connector Jl8 or J19, check
CD cables
and/or connections. Install cable if necessary.
0) Refer to link testing, Section 7.4
(4) Even if the link is operational, data transmissions could still
experience errors.

Refer to Section 7.4 for link testing.

7-4

7.3 DFM UNIT FAILS AUTOMATIC SELF-TEST
When the self-test is completed, the DR LED will come ON indicating that the DFM uni t passed the tests.
If the DR LED does not
come ON when the test appears to be finished (about 15 seconds),
then the DFM unit has failed the self-test.
When this happens,
other LEDs on the control module and channel module(s) light to
indicate a certain type of failure, as explained below.
The DFM automatic self-test routine checks the control module
memory first. If a problem is detected in the memory test, one of
the following LED status conditions will be displayed for a period
of about five seconds, and then the unit will try again until this
series of test is passed. No other LEDs on any other modules
should be ON if a memory failure occurs.
Automatic self-tests
cannot continue until memory error conditions are cleared.
The bottom two LEDs on the control module (labeled NR and DR) are
used to display memory error status as indicated below.

Condition

Control Module LED Status
SD

Probl em wi th RAM
autosize

Problem with ROM
checksum

Problem with host
memory

•
• •

Legend

a = OFF

• ON
=

7-5

After memory tests pass, the control module continues wi th the
rest of the automatic self-tests. The bottom two LEOs (NR and OR)
stay ON throughout the rest of these tests. As the units continue
the tests, the front panel LEOs light in a particular sequence,
(indicating which test is being run), and stay lit (indicating the
test has been passed) acco rd ing to the following 1 1st. The LEOs
light from the bottom to the top.
If an error is detected, the
sequence stops and all LEOs lit to that point flash.
The last
flashing LED indicates the nature of the failure according to the
descriptions below.
SD

Stays on during diagnostics

Unused (off)

Hardware config uration (memory or SCCs)

Host SCC

OMA (host)

Host interrupts/timer

Stays on during diagnostics

Stays on dur ing diagnostics

The channel line module LEOs also playa part in reporting
sel f-test d i agnost ic fa il ures.
Our ing sel f-test, these "LEOs
perform a sequence of ON/OFF conditions (simultaneously for two
channel modules) from the bottom up to the top.
The Channel 3 activity LED corresponds to a point in the
diagnostic routine where expansion memory is tested. At this
point, all eight LEDs go through another cycle where the
Expansion Board Memory Test Code (next page) applies.
After the expansion memory is checked, the LEDs are again interpreted by the Expansion Board Test Code listed below. Errors are
lndicated by the code flashing ON and OFF rapidly.
The last LEO
lit indicates which test has detected the error.

7-6

Expansion Board Test Code
Cl
C2

0
0

The top two LEOs designate the board number: C2 lit
for Channel board No.1; Cl and C2 lit for Channel
board No. 2

Unused (off)

Expansion memory

C5
C6
C7
C8

[The bottom four LEOs apply to expansion SCCs
Note: As long as one SCC in board No. 1 is
operational, the unit can function and will come up.
These LEOs indicate how many SCCs are functioning.]

0
0

Expansion Board Memory Test Code
The various expansion memory tests check hardware integrity of the
related data and addressing lines in the following manner.
Cl

Off

Walking 0s

Walking Is

C4
C5

0
0

Addressing, high
Too low

C6
C7

0
0

Addressing, low
Too high

If the automatic (powe r-up) self-test appears to be failing,
repeat it by pressing the System Reset (SR) switch.
Failure of this self-test cycle is a fatal error for the OFM unit.
If it continues to fail, DIGITAL Field Service must be called.

7-7

7.4 LINK OR CHANNEL COMPONENTS
When a problem occurs, the first thing is to determine whether
link or channel hardware (or configuration) is causing problems.
If the DR (device ready), CD (carrier detect), and NR (network
ready) LEOs are ON (not blinking), then the link is operational.
Even though the link may be operational, however, there still
could be other link problems such as data errors. It is important
that problems wi th the I ink be el iminated before proceed ing to
Channel Troubleshooting.
The status of the DR, CD, and NR control module indicators can
give some indication of a link problem.
•

Blinking DR indicator -- If the DR LED is blinking after
the unit has passed power-up, it is due to one of the
following:
Both units are set to type = master or type = slave,
Both units set to INVALID,
NVROM defaulted due to data storage failure (all
parameters for system, channel, and 1 ink are set to
default values due to an error in writing to
nonvolatile read only memory) •

•

CD indicator OFF -- When the link speed is set to async,
the carrier signal is generated by the DFM unit. If ~yn
chronous modems are used in the concentrated link, link
speed must be clocked by the modem. This means that link
speed must be set to sync. When link speed is set to
sync, the modem must generate the carrier signal. If the
link speed is set properly, a lack of carrier indication
(CD OFF) is probably due to one of the following:
A loose, broken, or dirty connector,
A malfunctioning modem,
A bad telephone line.
After cables, connectors, or other obvious possibilities
are checked, isolate the telephone line from the modems.
This can be accomplished by systematic use of the LBACK
test as described in Section 7.4.1.

•

NR indicator OFF -- The most common cause of failure to
obtain LINK READY is an improper configuration of link
speeds.
When synchronous modems are used, the 1 ink
should be set to sync.
When asynchronous modems are
used, or the BC22L cable is used, or the DFM unit is used
as a local data switching device, the link should be set
to async.
If link speed configuration is not the problem, one of
the link components is failing.

7-8

7.4.1 Isolating and Testing Link Components
The LBACK
(Link Loopback)
test is used to determine the
performance of the concentrated link by determining the number and
type of errors that occur.
A data pattern is generated and
checked by the local unit after it is looped back by the remote
DFM unit.
Test results show figures for transmit, receive, or
linkdrop errors. Normal data traffic must be discontinued while
running the LBACK test.
The LBACK test can be used to check the entire link or parts of
the link by placing the modems in different modes of 1oopback.
Modem loopback capabilities differ from modem to modem. Table 7-1
provides a matrix of loopback features associated with the
recommended modems from Digital Equipment Corporation.
For other
modems,
refer to manufacturer's documentation for 100pback
features. Obviously, if a particular loopback feature is not
ava ilable, then some of the var ious loopback tests descr ibed in
this section may not apply.
Table 7-1

Link Modem Loopback Test Matrix

Test Function

OF124

DF126

OF1270 OF1290

Analog Loopback

Analog Loopback Self-Test

x®
x®

Digital Loopback
Digital Loopback Self-Test
Remote Digital Loopback

Remote Digital Loopback Self-Test

End-to-End Self-Test

Has special unidirectional/bidirectional loopback feature.

Not local digital loopback, but a variation of remote digital
loopback.
Available with private line configurations only.

7-9

The test pattern generated during the LBACK test may be looped
back to the originating DFM unit by one of the following ways.
1.

Remote DFM.

Remote modem in loopback mode.

Local modem in loopback mode.

Special loopback test cable.

As an alternate to using the LBACK test pattern, most modems have
a self-test feature that allows the modem to supply the test
pattern.
In any case, after testing is completed, the SR switch
on the control module should be pushed to reset the multiplexer.
This is necessary to resume normal operation.
Link loopback testing generally isolates most problems. The Link
Signals test described in Section 7.4.1.8 is rarely needed.
The
Link Signals test also requires the use of a special cable which
is not provided as a standard item and, therefore, must be
fabricated as specified in Section C.6.

7-10

7.4.1.1 End-to-End LBACK Test -- This procedure checks the entire
link facility at full capacity (see figure 7-1).
statistics on
the number and type of errors that are detected are returned to
the supervisory terminal when the test is initiated from the
supervisory channel.
The remote multiplexer automatically responds to a LINKLOOP test
that is generated at the local multiplexer.

PERSONAL
COMPUTER

TERMINAL
ANALOG

COMPUTER
REMOTE DFM AUTOMATICALLY RESPONDS
WHEN LBACK IS INITIATED BY THE LOCAL DFM

P = PATIERN GENERATOR
C = PATIERN CHECKING

rcn
~

PERSONAL
COMPUTER

TERMINAL

TERMINAL
MKVSS-2015

Figure 7-1

End-to-End Link Loop Configuration

The LBACK test pattern may be initiated in two ways:
•

From the
7-1) •

supervisory channel

•

From the front of the control module by pressing IN the
Ml and M2 switches, and then pressing the SR switch.

7-11

(as described

Example

Execute the LBACK test from the supervisory channel.
Indicators
should be as shown below when the LBACK test is initiated from the
supervisory channel.
Modem module indicators vary depending on
the module used and whether local or remote. The chart below
shows all four recommended modem modules. Errors are reported to
the supervisory terminal as shown in Example 7-1.
When manual LBACK test is used (control module switches Ml and M2
pressed IN), indicator status is slightly different than shown
below.
The NR ind icator on the control module where the manual
test is initiated is OFF. Errors are indicated by blinking SA or
RA instead of being displayed at the terminal.
Also, the FB indicator on DF127/DF129 modem modules will be ON and
the HS indicator on the DF124 modem will be OFF if the tests are
executed at the lower speed(s).
Control Module
Local
Remote
DF124 Modem Module
Local
Remote
DFl26 Modem Module
Local
Remote
DF127/DF129 Modem Module
Local
Remote

x
* * •
* * • x x
* * • • •
* * • • •
* * • • •
x

x
o

•
•

• •
* * • • • • •

• •
• •
TM

* * • • •
* * • • •

Legend

= Don't Care (ON or OFF)

OFF

•

* = ON or Blinking
7-12

a
CS

x
x

EXAMPLE 7-1: RUNNING LBACK FROM THE SUPERVISORY CHANNEL
The LBACK test runs continuously, until terminated. The DFM unit
samples the test data periodically and sends the following
messages indicating test results.
Command Input: SYS) test link lback <RET)
Unit Response: Test Initiated.
(response with no errors)
TEST LINK LBACK)
(12-1-83

12:41) LINK 1 LBACK: NO ERRORS

(as errors occur)
TEST LINK LBACK)
(12-1-83

12:42)

LINK 1 LBACK:TRANSMIT

29/2%

RECEIVE

12/1%

LINK 1 LBACK:TRANSMIT

40/4%

RECEIVE

12/1%

LINK 1 LBACK:TRANSMIT

40/2%

RECEIVE

12/1%

LINKDROP=0
TEST LINK LBACK)
(12-1-83

12: 43)

LINKDROP=0
TEST LINK LBACK)
(12-1-83

12: 44)

LINKDROP=l

Errors are counted from the beginning of the test.
In this
example, the first report indicates that 29 transmit errors were
detected, which represents 2% of the test data transmitted at that
time.
The second report indicates that 4e transmit errors were
detected, which is 4% of the test data transmitted at that time.
The third report shows that no additional errors were detected
since the last report, so the percentage of errors for the amount
of test data sent dropped to 2%. The third report also shows that
a linkdrop was detected, that is, the link connection was
momentarily lost.
The information on received test data is
interpreted the same way.
The LBACK test is terminated by pressing RETURN.

7-13

7.4.1.2 Remote Modem Digital Loopback (Using DFM Pattern) -- This
test removes the remote multiplexer from the test circuit (see
Figure 7-2).
The first step is to put the remote modem into digital loopback
mode. This can be accomplished by pressing the RL switch IN on the
local modem. Pressing RL causes the system to reinitialize (about
45 seconds).
After reinitialization, the LBACK test is initiated at the local
DFM unit by using either the TEST command at the supervisory
channel as in Example 7-1, or using the manual feature (MI and
M2). The following indications should be displayed on the LEOs.

PERSONAL
COMPUTER

TERMINAL
ANALOG

COMPUTER
REMOTE DFM AUTOMATICAllY RESPONDS
WHEN lBACK IS INITIATED BY THE lOCAL DFM

P
C

= PATTERN GENERATOR

= PATTERN CHECKING

PERSONAL
COMPUTER

TERMINAL

TERMINAL
MKV85-2016

Figure 7-2

Remote Digital Loopback (Using DFM Pattern)

7-14

Control Module
Local
Remote
DF124 Modem Module
Local
Remote
DF126 Modem Module
Local
Remote
DF127/DF129 Modem Module
Local
Remote

* *

•

• • •
• •

• •
• •

* *
*
* * •• •• ••
* *
* * •• • ••
* *
0

• • •
• •
0

•
•

Legend
X

= Don't Care (ON or OFF)

= OFF
= ON
= ON or Blinking

•

The CE indicator on the local control module is OFF for
test when DF126 modems are used.

this

If the LED display is not as shown above, there may be a malfunction in one of the modem modules, the local control module, or the
telephone line may be bad.

7-15

7.4.1.3 Remote Modem Digital Loopback (Using Modem Pattern)
This test removes local and remote DFM units from the test circuit
(see Figure 7-3).
The first step is to put the remote modem into dig ital loopback
mode. This can be accomplished by pressing the RL switch IN on the
local modem. Pressing RL causes the system to reinitialize (about
45 seconds).
After reinitialization, a test pattern is generated and checked by
pressing the TP (Test Pattern) or ST (Self-Test) switch IN on the
local modem module (depends on the modem being used).
NOTE
The same circuit can be tested by simply
pressing the TP or ST switch IN on both
modem modules.
(LED indications are
identical).

PERSONAL
COMPUTER

TERMINAL
ANALOG

COMPUTER
REMOTE DFM AUTOMATICALLY RESPONDS
WHEN LBACK IS INITIATED BY THE LOCAL DFM

P = PATIERN GENERATOR
C = PATIERN CHECKING

-~
PERSONAL
COMPUTER

TERMINAL

TERMINAL
MKV85-2017

Figure 7-3

Remote Digital Loopback (Using Modem Pattern)

7-16

LED indicators on either control module (local or remote) are not
relevant to this test.
DF124 Modem Module
Local
Remote
DF126 Modem Module
Local
Remote
DF127/0F129 Modem Module
Local
Remote

• •
*
• •
*
* * •• •• • • •• •
* *
•
•
* * ••
•
•
* *
0
0

• • •
• •

Legend
X

•

= Don't Care (ON 0 r OFF)
= OFF
= ON
= ON or Blinking

If the LED display is not as shown above, one of the modems may be
malfunctioning or the telephone line may be bad.

7-17

7.4.1.4 Remote Modem Analog Loopback (Using DFM Pattern) -- This
test only applies to DF127/DF129 modem configurations; it cannot
be executed wi th DF124 or DF126 modems.
This test removes the
remote multiplexer as well as the digital portion of the remote
modem from the test circuit (see Figure 7-4).
This test requires that the bidirectional loopback option on DF127
or DF129 modems be enabled at the remote unit modem. Press the LL
switch IN on the remote unit modem. Pressing LL causes the system
to reinitialize (about 45 seconds).
After reinitialization, initiate the LBACK test at the local DFM
unit using either supervisory channel or manual (Ml and M2)
method.

PERSONAL
COMPUTER

TERMINAL

COMPUTER
REMOTE DFM AUTOMATICALLY RESPONDS
WHEN LBACK IS INITIATED BY THE LOCAL DFM

P = PATIERN GENERATOR
C PATIERN CHECKING

PERSONAL
COMPUTER

rcJ-\

TERMINAL

TERMINAL
MKV85-2018

Figure 7-4

Remote Analog Loopback (Using DFM Pattern)

7-18

Control Module
Local
Remote
DF127/DF129 Modem Module
Local
Remote

* *

•

* *
* *

• • •
• • •

Legend
X
0

•

= Don't Care (ON or OFF)
= OFF
= ON
= ON or Blinking

If the LED display is not as shown above, there may be a
malfunction in the local modem module, the local control module,
or the telephone 1 ine may be bad. There is a small possibil i ty
that the remote unit modem is malfunctioning.

7-19

7.4.1.5 Remote Modem Analog Loopback (Using Modem Pattern) -- The
test circuit for this procedure includes the local modem, the
link, and the analog portion of the remote modem (see Figure 7-5) •
This test applies only to DF127 and DF129 configurations.
This test requires that the bidirectional loopback option on DF127
or DF129 modems be enabled on the remote modem. Press the LL
switch IN on the remote modem.
Pressing LL causes the system to
reinitialize (about 45 seconds).
After reinitialization, a test pattern is generated and checked by
pressing the TP (Test Pattern) or ST (Self-Test) switch IN on the
local modem module (depends on the modem being used).

PERSONAL
COMPUTER

TERMINAL

! DIGITAL

COMPUTER
REMOTE DFM AUTOMATICALLY RESPONDS
WHEN LBACK IS INITIATED BY THE LOCAL DFM

P
C

= PATIERN GENERATOR
= PATIERN CHECKING

~
PERSONAL
COMPUTER

TERMINAL

TERMINAL
MKV85-2019

Figure 7-5

Remote Analog Loopback (Using Modern Pattern)

7-20

LED indicators on either control module (local or remote) are not
relevant to this test.
DF127/DF129 Modem Module
Local
Remote

* *
* *

•
•
• • •
0

•
•

Legend
X

•

= Don't Care (ON or OFF)
= OFF
= ON
= ON or Blinking

If the LED display is not as shown above, the local modem may be
malfunctioning or the telephone line may be bad. There is a small
possibility that the remote modem is malfunctioning.

7-21

7.4.1.6 Local Analog Loopback (Using DFM Pattern) -- This test
verifies the local modem and DFM unit up to the link RS-232-C
interface (see Figure 7-6). Press the LL switch IN on the local
modem.
Pressing LL causes the system to reinitialize (about 45
seconds) •
After reinitialization, initiate the LBACK test on the local DFM
unit using either the supervisory channel or manual (MI and M2)
method.

PERSONAL
COMPUTER

DIGITAL

ANALOG

DIGITAL

TERMINAL

COMPUTER
PERSONAL
COMPUTER
LOCAL ANALOG LOOP AT BOTH ENDS
ISOLATES THE TELEPHONE LINE
P = PATIERN GENERATOR
C PATIERN CHECKING

TERMINAL

MKV85-2020

Figure 7-6

Local Analog Loopback (Using DFM Pattern)

7-22

Control Module
Local
Remote
DF124 Modern Module
Local
Remote
DF126 Modern Module
Local
Remote
DF127/DF129 Mod ern Mod ul e
Local
Remote

* *

•

.* *

* • • • •

• • •

*
X

* • • • • • •
X

* • • •

•

Legend
X

Don't Care (ON or OFF)

OFF

•

ON or Blinking

The NR indicator on the local control module is OFF for this
The NR indicator on
test when DF124 or DF126 modems are used.
the local control mod ule is ON for this test when DF127 or DF129
moderns are used.

If the LED display is not as shown above, there may be a
malfunction in the local modem module or the local control module.

7-23

7.4.1.7 Local Analog Loopback (Using Modem Pattern) -- This test
verifies only the local modem module (see Figure 7-7). Press the
LL switch IN on the local modem. Pressing LL causes the system to
reinitialize (about 45 seconds).
After reinitialization, a test pattern is generated and checked by
pressing the TP (Test Pattern) or ST (Self-Test) switch IN on the
local modem module (depends on the modem being used).

PERSONAL
COMPUTER

DIGITAL

ANALOG

DIGITAL

TERMINAL

COMPUTER

PERSONAL
COMPUTER

LOCAL ANALOG LOOP AT BOTH ENDS
ISOLATES THE TELEPHONE LINE
P = PATIERN GENERATOR
C PATIERN CHECKING

TERMINAL

MKV85-2021

Figure 7-7

Local Analog Loopback (Using Modem Pattern)

7-24

LED indicators on either control module (local or remote) are not
relevant to this test.
DF124 Modem Module
Local
Remote
DF126 Modem Module
Local
Remote
DF127/DF129 Modem Module
Local
Remote

RD*

• • • • • •

RD*

• • •

• •

TM*

* *

•

during

the

test,

the

modem

above,

the

modem

Legend
X

= Don't Care (ON or OFF)

= OFF
= ON
= ON or Blinking

•

* If these indicators
detecting errors.

If the LED display
malfunctioning.

blink

not

7-25

shown

7.4.1.8 Link Signals Test -- The purpose of this test is to
verify concentrated link EIA signal toggle capabilities. The
special loopback test cable loops back all control signal pairs
(for example, DSR-DTR) while the unit raises and lowers voltages.
Passing this test ensures that none of the link EIA signals are
stuck high or low.
NOTE
The Link Signals test interferes with
data traffic on ALL channels because the
link cable must be disconnected.
A special loopback test cable, not available as a standard item,
is required for this test. This cable must be fabricated as
specified in Section C.6.
Refer to Figure 7-8 for the following test procedure.
1.

Unplug cables from Channel 4 and the link.

Plug the male end of the special loopback test cable into
Channel 4.

Plug the female end of the special loopback test cable
into the link connector.

Enter TEST LINK SIGNALS command line on supervisory
channel followed by a RETURN <RET).
The test beg ~ns.
Pressing RETURN after this test starts terminates the
test.

Following the test, the special loopback test cable must
be removed, link and Channel 4 cables reattached, and the
unit repowered to restore full operational capability.

7-26

PERSONAL
COMPUTER
CONDITIONS:
1. LINK DISCONNECTED
2. MAINTENANCE CABLE
CONNECTED TO
LINK AND CHANNEL 4.

COMPUTER

TERMINAL

SIGNALS TOGGLED AT LINK

~ ARE CHECKED BY CHANNEL 4

PERSONAL
COMPUTER

TERMINAL
MKV84-0295

Figure 7-8

Link Signals Test Configuration

7-27

7.4.2 Isolating and Testing Channel Components
The following is a list of some considerations for
associated with channel operations.
1.

Obvious Causes
a.
b.

Loose or broken connectors
Connectors being pulled out by weight of cable

Channel Configuration Pitfalls
a.
b.
c.
d.

problems

TYPE -- set to UNUSED?
FLOW CONTROL -- must be consistent with terminal and
CPU
SIGNALS -- set to other than ASSERT?
DATAPAR consistent with both terminal and CPU?

Isolate channel failure with:
a.

MONITOR Information
1)
2)

Xmitdata, Recvdata, and Signals readouts
Framerr, Bufovrf, Parerr, and Dataovrn figures

TEST Facilities
1)
2)
3)

Echo tests, Local and Remote
Pattern test
Signals (special loopback cable required.
Section C.6 for fabrication of test cable.)

See

7.4.2.1 Channel Configuration Pitfalls -- The following options
can impair channel operation unless configured properly.
•

Type Option.
Often the type option is mistakenly set to
value of unused.
This results in the channel being
disabled.

•

Flow Control Option. This function is very important and
is difficult for some users to understand.
Flow control
must be set to values consistent with the CPU and/or
terminal that are connected to that channel.

•

Signals Option.
Should be set to pass only when it is
important to allow changing the EIA signals at the other
end of the computer channel (that is, so the computer can
log off a user after a dial-up connection has been
terminated.)

•

Data Size and Parity Options.
consistent with CPU and terminal.

7-28

Must be set to values

7.4.2.2 Channel Monitoring Facilities -- Refer to the MONITOR
command, Chapter 5, for monitor procedures.
Only the systematic
use of the available functions is explained here.
When transmission is not continuous, the XMITDATA and RECVDATA
values show the last characters transmitted and received by the
terminal on the monitored channel.
If there is no terminal response or returned characters are
garbled, trace the data path to determine how far the data is
being correctly transmitted and received in the following manner.
•

Enter a character on a terminal connected
unit.

•

Look at the XMITDATA value for that channel on the local
unit to verify that the character is transmitted properly.

•

Look at the RECVDATA value on the remote unit to verify
that the character is correctly received by the unit and
sent to the channel.

•

Look at the XMITDATA value on the remote unit to see if
the character has been echoed by the CPU and transmitted
back by the remote unit.

•

Look at the RECVDATA value on the local unit to see if the
echoed character is received by the unit and sent to the
terminal correctly.
NOTE
Sometimes channels can be locked up by a
jammed flow control character. DC3 (13
hex) is an XOFF. Look for other control
characters that may be
jammed
and
inhibiting channel operation.

7-29

the

local

7.4.2.3 Channel Errors -- Alone, error indications listed below,
cannot pinpoint channel malfunctions, but they can help to
identify the problem.
•

Framing Errors: Possible causes of a significant number
of framing errors could be:
A mismatch in CPU, terminal, or multiplexer settings
for data size, parity, or speed.
A fa i I ing input/output dev ice (chi p)
port.

in the channel

A failing I/O device on the computer.
•

Buffer Overflow:
Buffer overflows always imply a flow
control problem.
Either flow control is not in use or it
has been set to an improper value.

•

Parity Errors: Parity errors usually indicate an improper
setting for data parity at the terminal, computer, or
multiplexer.

•

Data Overrun:
Data overrun is caused by more data being
rece ived on a port than the microprocessor can handle.
Typically, a significant number of framing errors will
also be present.

7.4.2.4 Local and Remote Echo Tests -- The purpose of the Local
Echo test is to verify the functioning of the channel cables and
the RS-232-C interface.
The Remote Echo test verifies the
integrity of channel cables as well as the concentrated link.
If
a terminal device is suspected faulty, either test verifies that
the terminal is sending, receiving, and properly displaying
characters (see Figure 7-9).
NOTE
Echo tests do not interfere with data
traffic on otfier channels.
Channel
transmit and receive speeds must agree.
If the channel echo configuration option for the channel being
tested is set to local, characters echoed back to the terminal
appear twice.
NOTE
Both Local and Remote Echo tests, as
well as Channel Pattern test, may also
be activated from terminals connected to
data channels once they are in command
mode.
Refer to the description of the TEST and TERMTEST commands in
Chapter 5 for examples on executing echo tests.

7-30

~
PERSONAL
COMPUTER
LOCAL
DATA IS LOOPED BACK
BY LOCAL DFM

COMPUTER
REMOTE
DATA IS LOOPED BACK
BY REMOTE DFM

PERSONAL
COMPUTER

TERMINAL
MKV85-2022

Figure 7-9

Channel Echo Test Configuration

7-31

7.4.2.5 Channel Pat tern Test -- The purpose of thi s test is to
verify channel hardware between the terminal and the DFM unit.
The DFM unit repeats the ASCII character set on the specified
channel until the test is terminated. The test is terminated by
pressing RETURN if at the supervisory channel or by pressing the
BREAK key if at the data channel (see Figure 7-10).
NOTE
The
Channel Pattern test does not
interfere with data traffic on any other
channel.
Garbled characters or a disrupted pattern on the terminal screen
indicates a hardware problem somewhere in the data path.
In most
instances this type of problem is caused by loose or dirty
connectors or wrong speeds.
Refer to the description of the TEST and TERMTEST commands in
Chapter 5 for examples on executing pattern tests.

PERSONAL
COMPUTER
REPEATING ASCII TEST
PATTERN IS GENERATED
ON SELECTED CHANNEL

lUi
J;~~
!/~
/

TERMINAL

...;-._i

COMPUTER

reD,

PERSONAL
COMPUTER

~
~
TERMINAL
MKV84·0293

Figure 7-10

Channel Pattern Test Configuration

7-32

7.4.2.6 Channel Signals Test -- The purpose of thi s test is to
verify channel EIA signal toggle capabilities.
The special
loopback test cable loops back all control signal pairs (for
example, DSR-DTR) while the unit raises and lowers voltages.
Passing this test ensures that none of the channel EIA signals are
stuck high or low (see Figure 7-11).
Echo and Pattern testing generally isolates most problems.
The
Channel Signals test described on the next page is rarely needed.
The Channel Signals test also requires the use of a special cable
which is not provided as a standard item and, therefore, must be
fabricated as specified in Section C.6.
NOTE
The Channel Signals test interferes with
data traffic on ALL ports because all
channel cables must be dIsconnected.

~
-'

PERSONAL
COMPUTER

ALL CHANNEL CABLES DISCONNECTED

TERMINAL

LINK DISCONNECTED

COMPUTER

I
I r~ MAINTENANCE CABLE PLUGGED

LiJ

INTO CHANNEL UNDER TEST.
OTHER CABLE END IS NOT
CONNECTED.

PERSONAL
COMPUTER

TERMINAL
MKV84-o289

Figure 7-11

Channel Signals Test Configuration

7-33

Test Procedure:
1.

Unplug cables from all channels and from the link port.

Plug the male end of the special loopback test cable into
the appropr iate channel port connector. (The female end
of the special loopback test cable is not connected
during the Channel Signals test.)

Select and execute the Channel Signals test for the
desired channel.

As other channels are tested, the special loopback test
cable is plugged into the appropriate channel port and
the test sequence is repeated.

When the Channel Signals test is complete, the unit must
be repowered after all cables have been replaced. This
restores full operational capability.

The DFM Channel Signals test consists of five separate tests
performed continuously and in sequence on tho. channel specified.
The Channel Signals test runs until terminated. The test is
terminated by pressing RETURN if at the supervisory channel or by
pressing the BREAK key if at the data channel. The output of each
step in the test is assigned a code.
Test 1 = Output code 00: No output signals asserted;
should be received.

none

Test 2 = Output code 03: Only CTS asserted; only RTS should be
received.
Test 3 = Output code 0C: Only DSR asserted; only DTR should be
received.
Test 4 = Output code 30: Only RI asserted; only RRI should be
received.
Test 5 = Output code C0: Only CAR asserted; only RCA should be
received.
The test results are not only displayed as a message on the
originating terminal, but are also displayed as a coded message on
the control module LEOs.

7-34

The Channel Signals test runs continuously until terminated from
the initiating terminal. As the unit passes the first sequence,
all LEOs on the control module light, and the following message is
displayed on the terminal.
TEST CHANNEL 1 SIGNALS) Passed
This message is displayed until either the test is terminated or
an error occurs.
An error detected in any of the five tests
results in:
•

A message to
format.

the

initiating

terminal

the

following

TEST CHANNEL 1 SIGNALS) FAILED: output=(03) input=(00000030)
•

Control module LEOs displaying the output code of the
failed test (see the following LEO outputs) •

Control module LEOs correspond to the "output=xx" portion of the
displayed message.
This allows the result of the test to be
determined via the front panel (visually) as well as from the
displayed message. Error indications (both terminal and LEOs)
remain on display until either another (different) error occurs or
the test is terminated.

7-35

During the Channel Signals test, each of the LEOs on the control
module represent one of the EIA signals.
LED 1
LED 2
LED 3
LED 4
LED 5
LED 6
LED 7
LED 8

(SO)
(RD)
(CD)
(SA)
(RA)
(CE)
(NR)
(DR)

TEST RESULTS

= CAR
= RCA
= RI
= RRI
= DSR
= DTR
= CTS
= RTS

(LED READINGS) ARE:

Test 1

Test 2

Test 3

Output = 00:
(SO) Off
(RO) Off
(CD) Off
(SA) Of f
(RA) Off
(CE) Off
(NR) Off
(DR) Off

Output = 03:
(SO) Off
(RO) Off
(CD) Off
(SA) Off
(RA) Off
(CE) Off
(NR) On
(DR) On

Output = 0C:
(SO) Off
(RO) Off
(CD) Off
(SA) Off
(RA) On
(CE) On
(NR) Off
(DR) Off

Test 4

Test 5

Output = 30:
(SO) Off
(RO) Off
(CD) On
(SA) On
(RA) Off
(CE) Off
(NR) Off
(DR) Off

Output = C0:
(SD) On
(RO) On
(CD) Off
(SA) Off
(RA) Off
(CE) Off
(NR) Off
(DR) Off

These codes display what is expected to
what is output for each step of the test.

7-36

received

well

APPENDIX A
DFM FUNCTIONAL SPECIFICATIONS

GENERAL SPECIFICATIONS
MULTIPLEXING TECHNIQUE
Statistical time division, dynamic bandwidth allocation with
variable block length.
MULTIPLEXING EFFICIENCY
To 800%, depending on application.

Typically 300% to 500%.

SYSTEM DESIGN
Multi-microprocessor design with internal DMA bus structure.
SYSTEM CONFIGURATION
Configuration of system parameters can be done by using either
the supervisory channel or enabled data channels with simpleto-use commands that are similar to DIGITAL VAX!VMS command
structure.
SUPERVISORY COMMAND CHANNEL
A special terminal connection that allows the system manager
to issue program, monitor, and test commands to the DFM
system. Access to command level is password protected. The
supervisory command channel program can also be accessed from
any data channel if program is not in use.
NETWORK CONTROL
All network functions (programming, monitoring, and diagnostic
tests) are performed by the supervisory command program.
Diagnostic capabilities include system, channel, and link
testing. Broadcast messages can be issued by the system
manager.
NETWORK MONITORING
The MONITOR command permits the system manager to display
status and/or error conditions for system, channel, and link
categories. All error counters can be cleared by a separate
command.
PARAMETER MEMORY
All configuration parameters are stored in nonvolatile, power
independent memory.

A-I

DFM FUNCTIONAL SPECIFICATIONS
AGGREGATE SPEED
Maximum aggregate speed of 153.6K bits/s which is 9699 bits/s
on all channels simultaneously.
CHANNEL END-TO-END DELAY
Varies with speed of channel and link, from 16 ms to 149 ms
(typically, less than 60 ms).
CHANNEL SPECIFICATIONS
CAPACITY
4-, 8-, 12- and l6-channel models.
ASYNCHRONOUS CHANNELS
All channels may operate in asynchronous mode (4, 8, 12 and
16). These channels can be operated as either dedicated or
switched.
SYNCHRONOUS CHANNELS
Synchronous mode supported on one-half the channels (1, 2, 5,
6, 9, 10, 13, and 14). Each sync channel can support message
blocks of 512, 1024, 2048, or 4998 bytes.
SYNCHRONOUS PROTOCOL
Multiplexes all synchronous data when RTS-CTS flow control is
selected (independent of protocol). Handles all protocol "NOT
using RTS-CTS flow control in transparent mode. Special
handling is included for Digital Equipment Corporation's DDCMP
protocol. No ARQ is performed on synchronous data channels.
SWITCHING
Asynchronous switched channels provide users with the ability
to select any other switched channel using simple commands.
CONTENTION
Asynchronous switched channels can contend for available
switched channels. Users are queued for busy channels.
SECURITY
Switched channels have "group access" codes to restrict users
from protected channels.
GROUP SELECTION
When switched channel users request a particular channel
group, the DFM searches for the first available channel and
establishes the connection.
PARAMETER INTERMIX
There are no intermix restrictions.

A-2

AUTOMATIC PARAMETER UPGRADE
Channel parameter changes at ei ther end of the network are
transferred
to
the
other
end
automatically
wi th
up-line/down-line load.
NON-INTERFERING
Channel programming does not interfere with other active
channels.
SPEEDS
50, 75, 110, 134.5, 159, 399, 699, 1299, 2499, 4899, 9699
bits/s; autobaud 150 to 9699 bits/s using CR character;
samebaud; split speeds of 1299/75, 2499/159, 75/1299, or
150/2400 bits/s. Synchronous 1299 to 9699 bits/s (internal or
external clocks).
SPEED CONVERSION
Channel speeds may be set to different values for either end
of a channel. The DFM unit provides automatic conversion of
speeds between ends.
DATA FORMAT
Async data: 5-, 6-, 7-, or a-bit data with even, odd, or no
parity; 1, 1.5, or 2 stop bits. All switched async channels
must have the same data format selections. Sync channels
support a-bit ASCII or EBCDIC with 2, 4, or 6 SYN characters.
FLOW CONTROL
X-ON/X-OFF, CTS-RTS, CTS-RLS, DSR-DTR, and EIA modem control
RTS-CTS.
FLOW CONTROL CONVERSION
Flow control conventions may be set to different values for
either end of a channel. The DFM unit provides automatic
translation of conventions between ends.
FILL CHARACTER BUFFERING
Allows a number of NUL characters to be selected by the user
for transmission following a CR character (asynchronous and
switched channels only).
ECHOPLEX
Local echo selection at either or both ends of a channel.
PRIORITY
Three levels of priority for each channel provide variable
message frames.
High is for large data requirements; low is
for background/noncritical data; and normal is for typical
data requirements in full-duplex configurations.

A-3

EIA DIAL-UP CONTROL
Programmable EIA dial-up modem control allows the DFM unit to
control automatic answer and call disconnect at either or both
ends of a channel.
INTERFACE
EIA RS-232-C/CCITT V.24/V.28; 25-pin female connector.
EIA SIGNALS
Four full-duplex EIA control signals per channel in each
direction.
STATUS/INDICATORS
Channel activity LED for each channel; channel utilization
statistics; channel error LED and error statistics.
MESSAGES
Allows either or both ends of the channel to receive broadcast
and automatic system error messages.
CONCENTRATED LINK SPECIFICATIONS
CAPACITY
Single
concentrated
asynchronous.

link,

either

synchronous

NRZI

SPEEDS
Synchronous 1200 to 19,200 bits/s; NRZI asynchronous 9600
bits/s only.
PROTOCOL
Conforms to ADCCP ANSI Standard X3.66.
of X.25 Level II, SDLC, and HDLC.

Protocol is a superset

ERROR DETECTION/CORRECTION
ARQ error correction with l6-bit CRC (asynchronous data only).
SATELLITE DELAY
Link protocol functions are enhanced for satellite networks of
one hop.
INTERFACE
EIA RS-232-C/CCITT V.24/V.28; 25-pin male connector.
INTEGRAL MODEM
The DFM enclosure provides space to install a DIGITAL modem
module. This option is field installable.

A-4

PHYSICAL SPECIFICATIONS
DIMENSIONS
22 • 5 ern H X 31. 5 ern W X 31 em D (8 • 87 in e h e s X 12. 37 in e h e s
X 12.25 inches).
WEIGHT
6.8 kg (15 1bs)
configuration.

8.6

(19

1bs),

depending

the

MOUNTING
Shelf/tabletop mounting only.
ENVIRONMENTAL REQUIREMENTS
TEMPERATURE
Operating:

0 0 to 40 0 C (32 0 to 104 0 F).

HUMIDITY, ALTITUDE
o to 95% noncondensing up to 2438 meters (8,000 feet).
FCC
Meets FCC Rules, Part 15J

Class A operation.

POWER
115 or 230 Vac; 50/60 Hz; 92 W
UL listed and CSA approved.
OPTIONS
INTEGRAL MODEMS
4800 bits/s V.27 private line modem and 9600 bits/s V.29
private line modem.

A-5

APPENDIX B
LINK MODEMS
B.l LINK MODEM OVERVIEW
The composite link output of the DFM ICP can use a standalone
modem or an internal integral modem module that fits into Slot 1
of the DFM enclosure.
There are several Digital Equipment
Corporation modems (both standalone and integral)
that are
available for use with the DFM unit. Table 8-1 lists each of these
modems by their speed characteristics and by model designation.
This appendix provides a brief description of the various userselectable options that are available with each modem and how each
selection is made. Each modem module is shipped from the factory
with the various options preset to select the most popular
configurations. For use with the DFM unit, however, some factory
options must be changed.
The tables in this append ix show what
options must be selected when the modem is used with the DFM unit.
These options are printed in blue for easy reference.
It is not
within the scope of this appendix to provide a description of each
option.
Detailed information on each of these modems, and
descriptions of modem options, is available by referring to
separate user's guides for each modem.
Part numbers for the
user's guides are listed in Table B-1. Refer to Chapter 3 for
descriptions of modem front panel controls and indicators.
Table 8-1

DFM Link Modems

Speed

Integral
(Private Line)

Standalone
Dial-Up

Section
Reference

User Guide
Part Number

1200
or
2400 bits/s

DFI24-AM
(2-wi re)

DF124-AA
(2-wi re)

B.3

EK-DF124-UG

1200
or
2400 bits/s

DFI26-AM
(4-wi re)

N/A

B.4

EK-DF126-UG

2400
or
4800 bits/s

DFI27-AM
(4-wire)

N/A

B.5

EK-DFI27-UG

4800/7200
or
9600 bits/s

DF129-AM
(4-wi re)

N/A

B.6

EK-DFI29-UG

B.2 LINK MODEM CONFIGURATIONS WITH THE DFM UNIT
Standalone modems connect to the DFM link connector J18 using a
standard straight-through cable such as BC22F or equivalent (see
Figure 8-1).

8-1

Integral modem modules are plugged into Slot I of the DFM enclosure as detailed in Chapter 3. Integral modem link connections
are made at connector J19 as shown in Figure 8-2. Connections to
Jl9 differ depending on the type of modem module used and whether
a 2- or 4-wire private telephone network is used. The inserts of
Figure 8-2 show these differences.
00
000
00000
0000

000000
00000
0000
000

0000

0000000
00000
00000
00
00000

GROUP B

SUPERVISORY
COMMAND
CHANNEL (SCC)
CONNECTOR J17(F)

GROUP A

ti,WNlNiill.'o'ii,D UNlytWlNHmO J 1
J 10 liYHNHNtNllmD U."llim,y.'HI1.','P J2
Uwnll,wuu,.D J3
J11
J9

J12~~~
J13~~~

U','Io'umm.'H",i)J

J 15 U,','m,o,omUlU.' D U...,umm,w%i)J7 ;
J16
QII""'"'''''fli)J
,"'IpPln •• ",

FUSE

DF100 SERIES
MODEM
ENCLOSURE
MKV8f>2023

Figure 8-1

Standalone Link Modem Connections

8-2

eo_o __
00000
00_0
000

SUPERVISORY
COMMAND
CHANNEL (SCC)
CONNECTOR Jt 7(F;

FUSE

4-WIRE DIRECT CONNECTIOr--

(OFl 26'OF 127 IOF129

4-WIRE LEASED
TELEPHONE CONNECTION

(OF1 26 / 0F127/0F1 291

2-WIRE IDF124 CONNECTIO~
PRIVATE
LINE
CONNECTIONS

"K~201'

Figure 8-2

Integral Modem Link Connections

8-3

B.3 THE DFl24 LINK MODEM
Whether using the DFl24 modem as an integral or standalone modem
with the DFM unit, certain modem options must be correctly
selected.
Figure 8-3 shows the location of swi tchpacks, while
Tables 8-2 through 8-5 indentify which options are required with
the DFM un i t and the swi tch posi t ions necessa ry to sel ect those
options.

SWITCHPACK S2
OFF ON

ClIlI 1
IIIIID 2

mIlD 3

KJ4
IDIID 5

oms

amo 7
CIIID 8
amo 9
ClDII10

SWITCHPACK S1
OFF ON
1

c:mm
c::om 2
CJIIII 3

amo 4

IIIDD 5

DID 6
IIIIID 7
CD 8
amo 9
lDIlD 10

o
[]

SWITCHPACK S3

OFF ON
DIIIJ 1

DIID 2
mm::J 3
mm:::::J 4

DDID 5
mm:::J 6
DIIID 7

ems

SWITCHPACK S4

OFF ON
IIII:J 1

SWITCHPACK S5 IS FOR FIELD
SERVICE USE ONLY. IT IS
NOT A USER FUNCTION AND
MUST NOT BE TOUCHED.
OFF ON
(IIID 1

IIID 2

IIID 3

CDIID 2

IIID 4
IUD 5
IUD S
IDD 7

DIIID 3

mao 4

c:. 5
CDlS

DIll 8

amo 7
amo 8
MKV85·2024

Figure 8-3

DF124-AM Module Layout and Switchpack Locations

8-4

The DF124-AM module also includes one additional switchpack (55)
which is provided solely for manufacring and Field Service use.
These switches should not be touched by the user.
They are
mentioned here for information only.
Table B-2

DF124-AM Switchpack 1 Selections

Option

Selection

Long
Enabled
Disabled
Space
Disconnect

OFF

Loss of
Enabled
Disabled
Carrier
Disconnect
Answer or
Originate

Ans
Orig

Slave
Clock

Receive
External

Master
Clock

Internal
External

Remote
Loopback

V.54
V.22

Parity
Select

Parity
No Parity

Local
Echo

Enabled
Disabled

Parity
Type

Odd
Even

Fallback
Select

celTT
BELL

518

OFF
ON

ON
OFF
OFF
ON

OFF
ON

ON
OFF
ON

OFF
ON
OFF
ON
OFF

8-5

Table B-3

DF124-AM Switchpack 2 Selections

Option

Selection

Character
Length

8 Bits
9 Bits
10 Bits
11 Bits

ON
OFF
ON
OFF

Async
Rate

Basic
Ex tended

Mode
Select

Sync
Async

Response
Message

Long
Short

Enabled
Disabled

Auto
Answer

Manual
Auto

PSTN or
PLTN

PSTN
PLTN

S10

ON
ON
OFF
OFF
ON
OFF
OFF
ON
OFF
ON
OFF
ON
ON
OFF
OFF
ON
OFF
·ON

-49 dBm
Signal
Detector -37 dBm
Threshold

Retrain

ON
OFF

Enabled
Disabled

B-6

Table 8-4

DFl24-AM Switchpack 3 Selections

Option

Selection

Abort
Timer

Enabled

Disabled

OFF

DTR

External

Forced ON
RTS

External

Interface
Rate Select
Control

Enabled

Guard
Tone
Select

Enabled

Pulse
Dialing
Duty Cycle
Interface
Local Loop
Control
Interface
Remote
Digital Loop
Control

ON
OFF

Forced ON

Disabled

OFF

Disabled

60%

OFF

67%

Enabled

ON
OFF

Disabled
Enabled

Disabled

OFF

B-7

Table B-5

DFI24-AM Switchpack 4 Selections

Option

Selection

PSTN
Xmit
Level

- 2 dBm

These switches are
disabled for u.s.
and Canadian installations. The option
is hard-wired to
select -10 dBrn •

PLTN
Xmit
Level

- 3 dBm
- 4 dBm
- 5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm
-10 dBm
-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm
-16 dBm
-17 dBm

- 2 dBm
- 3 dBm
- 4 dBm
- 5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm

OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON

-1 ~. db;'

-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm
-16 dBm
-17 dBm

B-8

OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON

OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON

B.4 THE DFl26 LINK MODEM
Whether using the DFl26 modem as an integral or standalone modem
with the DFM unit, certain modem options must be correctly
selected.
Figure 8-4 shows the location of swi tchpacks, while
Tables 8-6 through 8-11 indentify which options are required with
the DFM uni t and the swi tch posi tions necessary to select those
options.

SWITCHPACK S2

SWITCHPACK S1

OFF ON

OFF ON
CIIID 1

CJIIIID 1
a::::J 2
lIDO 3
IIDCJ 4
m::::J 5
CD 6
ClDID 7

em 2

IIIID 3
DIICJ 4
ao::J 5

III!CJ 6
DIID 7

em 8

IIIIlCI 8
IlIIlD 9

DlDD 10

IIIID 9
IIIIIID 10

SWITCH PACK 56

SWITCHPACK S3

OFF ON

CJDIIIIII ~
IIIIlIICJ t-J
CJIIIIIIID w

c.t-J

-=:J ~

lIDlIlICJ
-=:J ~

to)

-=:J~

5WITCHPACK 55

5WITCHPACK 54

OFF ON

IIIIIICJ ~

ImIICJ ~

IIlIII[::=J t-J

CJID1II] t-J
IIJID[:J to)

IIIIIIICJ
mIIIICJ ~

to)

IIlIIICJ ~

MKVB5-2033

Figure 8-4

DF126-AM Module Layout and Switchpack Locations

8-9

Table 8-6

DF126-AM Switchpack 1 Selections

Option

Selection

Scrambler Enabled
Disabled

ON
OFF

Terminal
Timing

Enabled
Disabled

Slave
Timing

Enabled
Disabled

Coding
Option

A Coding
B Coding

CTS
Delay

147-154 ms
8.5-9.35 ms
o ms
24.9-26.4 ms

Constant
Carrier

Enabled
Disabled

ON
ON
OFF
OFF

ON
OFF
ON
OFF

S1fIJ

ON
OFF
ON
OFF
ON
OFF

ON
OFF
ON
OFF

Indicate
Speed
Indicate/ Select
Select
Receiver
Squelch

ON
OFF

Maximum
Minimum

Reserved

NOT
USED

8-10

Table 8-7

DF126-AM Switchpack 2 Selections

Option

Selection

Abort
Timer

Disabled
Enabled

OFF

Remote
Loopback
Initiate

Disabled
Enabled

PSTN or
PLTN

PSTN
PLTN

Mode
Select

Sync
Async

Response
Message

Long
Short

AutoAnswer

Auto
Manual

Parity
No Parity

Local
Echo

Disabled
Enabled

OFF
ON
OFF
ON

OFF
OFF
ON
ON

SIB

Ol~

OFF
ON
ON
OFF
OFF
ON
OFF
ON
OFF
ON

Character 11 Bits
Length
10 Bits
9 Bits
8 Bits
Parity
Select

ON
OFF
OFF
ON

B-ll

Table 8-8

DF126-AM Switchpack 3 Selections

Option

Selection

Parity
Type

Odd
Even

ON
OFF

Secondary
Data Port

Enabled
Disabled

NOT NOT
USED USED

DF126-AM Switchpack 4 Selections

Option

Selection

PR/PC*

Permissive
Programmed

OFF
ON

ON
OFF

NOT
USED

Reserved
MI

ON
OFF

Reserved

Table 8-9

Disabled
Enabled

OFF
ON

* Only one may be ON, the other must be OFF.
Permissive is used with RJ11C/CA11A service
and programmed is used with RJ41S/RJ45S/
CA41A/CA45A type service.

8-12

Table B-l~ DF126-AM Switchpack 5 Selections
Option
Private Line
Xmit
Level

Selection

0 dBm

OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON

OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON

OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON

- 1 dBm
- 2 dBm
- 3 dBm
- 4 dBm
- 5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm
-1~ dBm
-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm

Table 8-11 DF126-AM Switchpack 6 Selections
Option

Selection

Carrier
Detect
Level

-43 dBm

OFF
ON

-33 dBm

Reserved
Equalizer*

OFF
ON

ON
OFF

NOT
USED
In
Out

*Only one may be ON, the other must be OFF.

B-13

8.5 THE DF127 LINK MODEM
Whether using the DF127 modem as an integral or standalone modem
with the DFM unit, certain modem options must be correctly
selected. There are three versions of the DF127 modem module that
can be used with the DFM unit.
The early version (below serial
number NQ0l800) can only be used as an integral modem. It cannot
be used in the DF100 series standalone enclosure.
.
Version 2 of the DF127 modem modules can be used in both integral
or standalone configurations and consists of modules between
serial number NQ0l800 and NQ03000.
Version 3 (above ser ial number NQ03000) is similar to Version 2
and has been redesigned to take advantage of new state-of-the-art
technology and components.
Modem options offered on Versions 2
and 3 are the same, however, component layout and placement of
switchpacks are different than Version 2.
Modem options and
switch selections on Version 1 are completely different than
Versions 2 and 3.
Figures 8-5, 8-6, and 8-7 show each of the
DF127 versions.
Each modem module must be removed from the DFM enclosure to access
the switches.
CAUTION
Disconnect power to the unit before
removing the integral modem module from
Slot 1 for switchpack reconfiguration.

8-14

8.5.1 DF127 Version 1 Configuration Options
There are two types of switch selections on the DF127 Version 1
module: a 10-position raised rocker switchpack that selects modem
options and a 16-posi tion sl ide swi tch that adj usts the analog
output level. Refer to Figure 8-5 for the locations of switchpack
and analog output level adjustments on the modem. Refer to Tables
8-12 and 8-13 for DF127 Version 1 option selections.

ANALOG OUTPUT
ATIENUATOR

PIGGYBACK
MODEM BOARD

INTERFACE CONTROL
BOARD

M~~4
It)P4

CD~

,.....

co
en

4
4
4
4

It)

•

-L....-

OPTIONS
SWITCH PACK

RAISED
ROCKER
TYPE
USE POINTED OBJECT
DO NOT USE LEAD
PENCIL

MKV84·0296

Figure 8-5

DF127-AM Module (Version 1) Layout and
Switchpack Locations

8-15

Table B-12

Switchpack Options

Switch
Number

Function

Switch Position
Closed
Open

Transmitter Clock

External Clock

Internal Clock

Equalizer Sampling
Period

T/2

Carrier Control

RTS Controlled

Continuous

Loopback Control

Bi-Directional

Uni-Directional

SPARE - Not Used

Data Set Ready (DSR)
Control

Normal Data

Power-up

Threshold Level Select

-26 dBm

-43 dBm

SPARE - Not Used

Automatic Fallback

Disabled

Enabled

Remote Loopback

Disabled

Enabled

Table B-13

Analog Output Attenuation

position

Attenuation
~

dBm

- 1 dBm

3
4
5

- 2 dBm
- 3 dBm
- 4 dBm
- 5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm
-1~ dBm
-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm

6
7
8
9
10
11

12
13
14
15

8-16

B.5.2 DF127 Version 2 and 3 Configuration Options
Versions 2 and 3 of the DF127 modern module contain three switchpacks and several jumpers to select modem options. See Figure 8-6
for Version 2 jumper/switchpack layout and Figure 8-7 for Version
3 jumper/switchpack layout. Option selections are the same for
Versions 2 and 3 (see Tables 8-14 and 8-15 for jumpers, and 8-16
through 8-19 for swi tches) •
Swi tchpack locations, however, are
different.

JUMPER J6

JUMPER J3
140-013

00
0-0
00

FACTORY U5E
ONLY

0-0

JUMPER J5

2
10qp3
JUMPER J7

5WITCHPACK 51

5WITCHPACK 52

5WITCHPACK 53

MKVS5-2025

Figure 8-6

DFI27-AM Module (Version 2) Layout and
Switchpack Locations

8-17

JUMPER J8
JUMPER J5
2QOQOOOQ14
100000-0013

o
FACTORY U5E
ONLY

JUMPER J3

o
20-0 4

JUMPER J6 1 00 3

5WITCHPACK 51

5WITCHPACK 52

5WITCHPACK 53

ON
OFF

MKV85-2026

Figure 8-7

DF127-AM Module (Version 3) Layout and
Switchpack Locations

8-18

Table 8-14

Jumper Selections for Version 2

OPtion

Selection

Jumpers*
J3

1-2 3-4 4-6 7-8 9-10 11-12 13-14 1-2 1-2 2-3
Speed
Indicate/
Select

Indicate

Select

OUT IN

OUT IN
OUT
OUT

Interface
Local Loop
Control

Enabled

Disabled

OUT IN

Interface
Remote
Digital
Loop
Control

Enabled

OUT

Disabled

OUT

Protective
Ground to
Modem
Ground

Enabled

Disabled

OUT

2- or 4Wire
Private
Line

2-Wire

4-Wire

OUT IN

* Jumpers on J4 are used

OUT

for special maintenance testing and
jumper J5 is for factory use only.
Each of these are not user
functions.

8-19

Table 8-15

Jumper Selections for Version 3

Option

Selection

Speed
Indicate/
Select

Indicate

OUT

Select

OUT

Interface
Local Loop
Control

Jumpers*
J8
J6
J5
1-2 3-4 5-6 7-8 9-11 11-12 13-14 1-2 1-3 2-4

Enabled

OUT IN

Disabled

OUT

Interface
Remote
Digital
Loop
Control

Enabled

OUT IN

Disabled

Protective
Ground to
Modem
Ground

Enabled

Disabled

OUT

2- or 4Wire
Private
Line

OUT

2-Wire

4-Wire

OUT IN

* Jumpers on J2 are

OUT

used for special maintenance testing and
Each of these are not use r

j urnper J 3 is for factory use only.

functions.

8-20

Table 8-16

DF127-AM Switchpack 1 Selections for Version 2

Option

Selection

Transmit
Clock 1

External
Internal

ON
OFF

Equalizer T
Sampl ing T/2 CD
Carrier
Control

RS
continuousCD

Loopback
Control

Bi-Direction
Uni-Direction

Squelch

Enabled
Di sabl ed CD

Transmit
Clock 2

Slave
Independent®

Remote
Loopback

Disabled
Enabled

S18

ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF

ON
OFF

<15 ms
TrainingCD&®

ON
OFF

Carrier
-26 dB~
Threshold -43 dBm
Data Qual 10- 43
Threshold 10RS to CS

ON
OFF
ON
.oFF

NOTES:
These options must be set to OFF when the DF127 modem is used
with the DFM unit.
option only applies when the Transmit Clock 1 is set to
® This
internal.
This option is enabled or disabled by switchpack 2, switch 1.
CD When
enabled, retraining occurs when the error rate reaches the
data quality threshold selected by switchpack 1, switch 8.
When this switch is OFF, the training period varies with modem
speed and the selection of switchpack 2, switch 3. This option
is valid only in continuous carrier mode.

8-21

Table 8-17

DFI27-AM Switchpack 1 Selections for Version 3

Option

Selection

Transmit
Clock 1

External
Internal

ON
OFF

Equalizer T
Sampling T/2CD

RS
continuousCD

Loopback
Control

8i-Direction
Uni-Direction

Squelch

Enabled
DisabledCD

Transmit
Clock 2

Slave
Independent

Remote
Loopback

S10

ON
OFF
ON
OFF

ON
OFF

ON
OFF
ON
OFF

<3 ms
50 ms CD

ON
OFF

Carrier
-26 dBm
Threshold -43 dBm

RS to CS

ON
OFF

Carrier
Control

Data Qual 1",-4
Threshold 10- 3

ON
OFF

Disabled
Enabled

ON
OFF

NOTES:
These options must be set to OFF when the DF127 modem is used
with the DFM unit.
option only applies when the Transmit Clock 1 is set to
CD This
internal.
This option is enabled or disabled by switchpack 2, switch 1.
When enabled, retraining occurs when the error rate reaches
the data quality threshold selected by switchpack 1, switch 8.
This option is valid only in continuous carrier mode
(switchpack 1, switch 3 = ON) when the modems are already
trained. In RS controlled carrier mode (switc~pack 1, switch 3
= OFF) switch 9 has no effect. In this mode RS to CS delay is
dependent on modem speed and the training interval selection
of switchpack 2, switch 3.

B-22

Table B-18

DF127-AM switchpack 2 Selections (Versions 2 and 3)

Option

Selection

Data
Quality
Retrain

Disabled
Enabled0&0

ON
OFF

Round
Robin
Retrain

Disabled
Enabled

Training
Interval

Short
Long0&®

ON
OFF

Reserved

NOT
USED

NOTES:

CD This switch works together with switchpack 1, switch 8.

These options must be set to OFF when the DF127 modern is used
with the DFM unit.

This switch is valid only in RS controlled carrier mode.
In
CD continuous
carrier mode, the round-robin feature is always
enabled, regardless of the position of this switch.
This switch selects the training interval
when switchpack 1, switch 9 is set to OFF.
Speed

Long Interval
(Swi tch 3 OFF)

Normal (4800 bits/s)
Fallback (2400 bits/s)

708

943 ms

B-23

(see chart below)
Short Interval
(Switch 3 ON)
50 ms
66 ms

Table B-19
Option
PLTN
Xmit Level
Attenuation

DF127-AM Switchpack 3 Selections (Versions 2 and 3)
Selection

0 dBrn

OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON

OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON

OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON

1 dBm
2 dBm
3 dBm
4 dBm
5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm
-1~ dBm
-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm

8-24

8.6 THE DF129 LINK MODEM
Whether using the DF129 modem as an integral or standalone modem
with the DFM unit, certain modem options must be correctly
selected.
Like the DF127 modem, there are three versions of the
DF129 modem module that can be used with the DFM unit. The early
version (below serial number NQ01700) can only be used as an
integral modem.
It cannot be used in the DF100 series standalone
enclosure.
DF129 Version 2 can be used in both integral or standalone
configurations and consists of modules between serial number
NQ01700 and NQ04000.
Version 3 (above serial number NQ04000) is a similar to Version 2
and has been redesigned to take advantage of new state-of-the-art
technology and components.
Modem options offered on Versions 2
and 3 are the same, however, component layout and placement of
switchpacks are different than Version 2.
Modem options and
switch selections on Version 1 are completely different than
Versions 2 and 3.
Figures 8-8, 8-9, and 8-10 show each of the
DF129 versions.
Each modem module must be removed from the DFM enclosure to access
the switches.
CAUTION
Disconnect power to the unit before
removing the integral modern module from
Slot 1 for switchpack reconfiguration.

8-25

8.6.1 DF129 Version 1 Configuration Options
There are two types of swi tch selections on the DF129 Version 1
module: a 10-position raised rocker switchpack that selects modem
options and a 16-posi tion sl ide swi tch that adj usts the analog
output level. Refer to Figure 8-8 for the locations of switchpack
and analog output level adjustments on the modem. Refer to Tables
8-20 and 8-21 for DF129 Version 1 option selections.

ANALOG OUTPUT
ATTENUATOR
PIGGYBACK
MODEM BOARD

INTERFACE CONTROL
BOARD

(7)

.....
.....
N
.....

...
M

...
'It

-'--

OPTIONS
SWITCH PACK

RAISED
ROCKER
TYPE
USE POINTED OBJECT
DO NOT USE LEAD
PENCIL

MKV84-0296

Figure 8-8

DF129-AM Module (Version 1) Layout and
Switchpack Locations

8-26

Table B-20
Switch
Number

Switchpack Options

Function

Switch Position
Closed
Open

Transmitter Clock

External Clock

Internal Clock

Equalizer Sampling
Period

T/2

Carrier Control

RTS Controlled

Continuous

Loopback Control

Bi-Directional

Uni-Directional

SPARE - Not Used

Data Set Ready (DSR)
Control

No rmal Da ta

Power-up

Threshold Level Select

-26 dBm

-43 dBm

SPARE - Not Used

Automatic Fallback

Disabled

Enabled

Remote Loopbac k

Disabled

Enabled

Table B-21

Analog Output Attenuation

position

Attenuation

1
2
3

0 dBm
- 1 dBm
- 2 dBm
- 3 dBm
- 4 dBm
- 5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm
-10 dBm
-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm

5
6
7
8
9
10

11
12
13
14
15
16

8-27

8.6.2 DF129 Version 2 and 3 Configuration options
Versions 2 and 3 of the DF129 modem module contain three switchpacks and several jumpers to select modem options. See Figure 8-9
for Version 2 jumper/switchpack layout and Figure 8-10 for Version
3 j umper/swi tchpack layout. Option selections are the same for
Versions 2 and 3 (see Tables 8-22 and B-23 for jumpers, and 8-24,
8-25, and 8-26 for switches). switchpack locations, however, are
different.
JUMPER J6

JUMPER J3

14 ~ 13
00
0<>
00

FACTORY U5E
ONLY

0<>

JUMPER J5

2
10Q..P3
JUMPER J7

5WITCHPACK 51

5WITCHPACK 52

5WITCHPACK 53

MKV85-2025

Figure 8-9

DF129-AM Module (Version 2) Layout and
Switchpack Locations

8-28

JUMPER J8
JUMPER J5

2Qo Q OOOQ'4
,60600-06'3

o
FACTORY USE
ONLY

JUMPER J3

o
20-0 4

JUMPER J6 1 00 3

SWITCHPACK S1

SWITCH PACK S2

SWITCH PACK S3

ON
OFF

MKVS5·2026

Figure 8-10

DF129-AM Module (Version 3) Layout and
Switchpack Locations

8-29

Table 8-22

Jumper Selections for Version 2

Option

Selection

Jumpers*
J7
J6
J3
1-2 3-4 4-6 7-8 9-19 11-12 13-14 1-2 1-2 2-3

Speed
Indicate/
Select

Indicate

Select

OUT IN

Interface
Local Loop
Control
Interface
Remote
Dig i tal
Loop
Control
Protective
Ground to
Modem
Ground
2- or 4Wire
Private
Line

OUT IN

OUT

Enabled

Disabled

OUT IN

OUT

Enabled

OUT

Disabled

OUT

Enabled

Disabled

OUT

2-Wire

4-Wi re

OUT

OUT IN

CD Does not apply to DF 129 modem.
* Jumpers on J4 are used

for special maintenance testing and
jumper J5 is for factory use only.
Each of these are not user
functions.

8-30

Table B-23

Jumper Selections for Version 3

Option

Selection

Jumpers*
J5

1-2 3-4 5-6 7-8 9-11 11-12 13-14 1-2 1-3 2-4

Speed
Indicate/
Select

Indicate

OUT

Select

OUT

Interface
Local Loop
Control

Enabled

OUT IN

Disabled

Interface
Remote
Dig i tal
Loop
Control

Enabled

OUT IN

Disabled

Protective
Ground to
Modem
Ground

Enabled

Disabled

OUT

2- or 4Wire
Private
Line

2-Wire

OUT

4-Wire

OUT

OUT IN

CD Does not apply to DF129 modem.
* Jumpers on J2 are used for special maintenance testing and
jumper J3 is for factory use only.
functions.

8-31

Each of these are not user

Table 8-24

DF129-AM 5witchpack 1 Selections

Option

Selection

Transmit
Clock 1

External
Internal

ON
OFF

Equalizer T
Sampling T/2 Q)

R5
Continuous Q)

Loopback
Control

Si-Direction
Uni-Direction

5quelch

Enabled
Disabled Q)

Transmit
Clock 2

5lave
Independent

5lS

ON
OFF
ON
OFF
ON
OFF

OFF
ON
OFF

ON
OFF

<15 ms
253

Remote
Loopback

ON
OFF

Carrier
-26 dBm
Threshold -43 dBm

R5 to CS

ON
OFF

Carrier
Control

Data Qual 10-~j
Threshold 10-

msQ)&@

Disabled
Enabled

ON
OFF

NOTES:
These options must be set to OFF when the DF129 modem is used
with the DFM unit.
This option only applies when the Transmit Clock 1 is set to
internal.
This option is enabled or disabled by switchpack 2, switch 1.
CD When
enabled, retraining occurs when the error rate reaches the
data quality threshold selected by switchpack 1, switch 8.
This option is valid only in continuous carrier mode.

B-32

Table 8-25

DF129-AM Switchpack 2 Selections

Option

Selection

Data
Quality
Retrain

Disabled
Enabled(D&0

Round
Robin
Retrain

Disabled
Enabled®

OFF

ON
OFF

NOT
USED

Not Used
On DF129

NOT
USED

Reserved
NOTES:

<D This switch works together with switchpack 1, switch 8.

These options must be set to OFF when the DF129 modem is used
with the DFM unit.

This switch is valid only in RS controlled carrier mode.
In
CD continuous
carrier mode, the round-robin feature is always
enabled, regardless of the position of this switch.

8-33

Table 8-26 DF129-AM Switchpack 3 Selections
Option
PLTN
Xmit Level
Attenuation

Selection

0 dBr:1

OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON

OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON

OFF
OFF
OFF
OFF
ON
ON
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON

- 1 dBm
- 2 dBm
- 3 dBm
- 4 dBm
- 5 dBm
- 6 dBm
- 7 dBm
- 8 dBm
- 9 dBm
-10 dBm
-11 dBm
-12 dBm
-13 dBm
-14 dBm
-15 dBm

B-34

APPENDIX C
CABLES

C.l GENERAL
This appendix outlines pin connections and EIA signal assignments
for the cables used with the DFM system. For more information on
cables and connections, see Section 2.8.
SIGNAL ABBREVIATIONS
Abbreviations used in the wiring tables
Unidentified pin connections are not used.
CTS
DCE
DSR
DTE
DTR
ERC
ETC
CD
PG
RC
RD
RI
RLS
RRI
RTS
SG
TC
TD

Clear to send
Data communications equipment
Data set ready
Data terminal equipment
Data terminal ready
External receive clock
External transmit clock
Carrier detect
Protective ground
Receive clock
Received data
Ring
Reverse carrier (reverse CD)
Reverse ring (busy out)
Request to send
Signal ground
Transmit clock
Transmitted data

C-l

are

listed

below.

C.2 CABLE E (BC22E) DFM TO ASYNCHRONOUS DTE
The BC22E cable is used for connecting an asynchronous DTE to a
DFM channel. (The DFM unit presents a DCE interface on channel
ports. )
The BC22E cable is not symmetrical (see Figure C-l). The male
connector must be attached to the DFM unit.

PG
TO
RO
RTS
CTS
OSR
SG
CD
RlS

OTR
RI
RRI

01
02
03
04
05
06
07
08
o 11
o 12
o 18
o 19
o 20
o 22
o 23
025

10
20
30
40
50
60
70
80
11 0
12 0
18 0
19 0
200
22 0
230
25 0

MKV85-2027

Fig ure C-l

BC22E Cable -- DFM to Asynchronous DTE

C-2

C.3 CABLE F (BC22F) DFM TO SYNCHRONOUS DTE
The BC22F cable is used to connect the DFM link port to an
external modem. It is also used to connect a DFM synchronous
channel to a synchronous or DDCMP device.
The BC22F cable is symmetrical (see Figure C-2).

TO
RO
RTS
CTS
OSR
SG

CD
ERC
ETC
RLS

TC
RC
OTR
RI

RRI

1 0
2 0
3 0
4

5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

o 2
o 3

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

o 5

o 6
o 7
o 8
o 9
0
0
0
0
0
0
0
0
0
0

10
11
12
13
14
15
16
17
18
19

o 20
o 21
o 22
o 23
o 24
o 25
MKV85·2028

Figure C-2

BC22F Cable -- DFM to Synchronous DTE

C-3

C.4 CABLE L (BC22L) SPECIAL DIRECT LINK
The BC22L cable is used to directly connect two DFM units (no
modems in between) by means of connector J18 on both un i ts.
The
link speed selection must be set to async on both DFM units when
using the direct link configuration. In accordance with EIA
standards, a maximum distance of 15.24 m (50 ft) between units is
recommended.
The BC22L cable may also be used to connect the units for the
preinstallation benchtest when integral modems are not purchased
(see Chapter 3). The BC22L cable is symmetrical (see Figure C-3).

TO
Ro
RTS
CTS
oSR
SG
CD
oTR

;g
:g

j~ 1 >< i ~L
MKV85-2029

Fig ure C-3

BC22L Cable -- Direct Link

C-4

C.s CABLE M (BC22M) DCE TO DCE CROSSOVER
The BC22M cable is used to connect a DFM channel to a modem. This
cable is frequently called a "crosspatch" or "crossover" cable
because it crosses EIA signals inside the cable. By using the
BC22M cable and the proper software parameter settings to handle a
channel to modem connection, the DFM unit passes the four EIA
signals (CTS, DSR, CD, and RI) through to the device connected at
the corresponding remote-end device. The RTS and DTR from the
remote-end device are passed through to the modem. This is
accomplished by crossing CTS with RTS, DSR with DTR, connecting RC
and TC from modem to external clocks on the DFM unit, and
connecting RI pins to RRI at the DFM unit for a busy signal.
The BC22M cable is not a symmetrical cable. It has two male ends.
PI must be connected to the DFM unit (see Figure C-4).
P1

TO
RO
RTS
CTS
OSR
SG

~~
~~

ERC
ETC
CD

6
7

10
11
15
17

OTR
RI
RRI

~ ;~
MKV85·2030

Figure C-4

BC22M Cable -- DCE to DCE Crossover (Shielded)

C-5

C.6 CABLE T SPECIAL LOOPBACK TEST CABLE
This special cable is required to run the Signals test for the
link and DFM channels. This cable is NOT available as a standard
item and must be fabricated according to the connections shown in
Fig ure C-5.

FEMALE

MALE
TO

RD
RTS
CTS

DSR

~..... 5

.....
4 ""

5 '"
6 0
.....
7 '"

SG
CD

.....
8 ""

RLS

11 '"

,..

-- 67

0 8

..... 15 XMIT CLOCK
..... 17 RECV CLOCK

~'"

DTR
RI

RRI

0 20
20 0
--4--------~O
22
22~
25

MKV85-2031

Figure C-5

Special Signals Loopback Test Cable

C-6

APPENDIX D
CONFIGURATION WORKSHEET

GENERAL
The Configuration Worksheet provides a hard-copy reference of the
network configuration. It shows the location and mix of terminals
and computers connected by the DFM system as well as the operating
parameters of each device.
It is recommended that copies of the filled-in worksheet be distributed to data channel users. Information on the worksheet is
necessary for switched channel operators to use the system
effectively. Each operator must know which channels are switched,
the associated channel IDs, and the group access assignments.
Refer to Figure 6-2 for an example of how to fill out the
Configuration Worksheet. Use copies of the blanks provided here in
this appendix when reconfiguring the system.

0-1

CHART 1
INTELLIGENT COMMUNICATION PROCESSOR WORKSHEET

REMOTE:

LOCAL
LOCATION

LOCATION

MODEL #

MODEL # _ _ _ _ _ _ _ _ _ _ __

SERIAL #

SYSTEM PARAMETERS

SYSTEM PARAMETERS
NAME _ _ _ _ _ _ _ _ _

NAME ___ . _____ . __
16 CHARACTERS (MAX)
TYPE MASTER []
SLAVE
[J

16 CHARACTERS (MAXI
TYPE MASTER 0
SLAVE
0
.CONFIGURATION: VALID 0

JltONFIGURATION VALID []
AUTODISCONNECT
TIMEOUT

AUTODISCONNECT: ,..-----"-1
TIMEOUT
(1 to 225 SEC)

,-I_ _ _ _...J

(1 to 225 SEC,

SWITCHED PARAMETERS

SW DATAPAR
DATA 8 C

SW DATAPAR
PARITY NONE
DATA 8 ::::::;
7 '-'
ODD EVEN
6

7 C
6 C
5 G

5L:

SW STOPSITS

1
1.5

SW SIGNALS ASSERT
PASS

PARITY: NONE 0
ODD ~
EVEN 0

SW STOPBITS

COMMAND CHARACTER
(HEX 00 TO 1 F}

[]

15
2

0
0

SW SIGNALS ASSERT lJ
PASS
r·

DD DO
HEX

HEX

COMMAND CHARACTER
(HEX 00 to 1 F}

DO DO
HEX

HEX

GROUP NAMES

LINK PARAMETERS
SPEED

SYNC
ASYNC C

DELAY

NORMAL 0
SATELLITE 0

LINK CHARACTERISTICS MUST BE SET THE SAME AT BOTH ENDS
*CO\JFIGURATION IS VERY CRITICAL REFER TO SECTION 6.5.3
MKV85·2795

CHART 2A

CHANNELS

REMOTE

LOCAL
2

U=UNUSED
w

e..

S=SYNC SEE CHART 3

A=ASYNC

SW=SWITCHED

STOPBITS

1.1.5.2

SIGNALS

A = ASSERT
L = L·DIAL
R = R·DIAL
B = 2·DIAL
P = PASS

DATAPAR

N = NONE
0= ODD
E = EVEN

>....l

u
>V'J

SPEED

1200
2400
4800
9600
AUTO BAUD
OTHER(j)

FLOW

NONE
XO"""B

u....

XO~C

XO~T

V'J

..tl

u
z
>V'J

CTS·RTS
OTHER(2)

<
FILLCHAR

(0·2551

PRIORITY

L-LOW
N=NORMAL
H=HIGH

ECHO
MESSAGES
COMTERM
COMECHO

SWITCHED
E = ENABLE
D = DISABLE
ASYNC
N = NONE
L = LOCAL
R = REMOTE
B = BOTH

AUTODISC

E = ENABLE
D = DISABLE

CHANNEL 10

A TO Z

:r
u

GROUP ACCESS

10· LIST

SIGNALS

N = NONE
0= DIAL
DIAL'"

....l

§
V'J

I I I I I I I I I

I I I II I I I I

riI'=

A = ASSER\-;'
ASSER

A4'=

<D OTHER SPEED SELECTIONS
1=50. 2=75. 3=110.4=134.5. 5=150.
6=300.7=600. (ASYNC ONLY S=SAMEBAUD!
SPLIT· SPEED 8=7511200,9=1200/75.
10=150:2400. 1 , =2400/150

OTHER FLOW SELECTIONS
l=XON·B, 2=XON·C. 3=XON·T.
4=DSR·DTR,5=CTSH·RlSH.
6=CTSH·RLSL. 7=CTSL·RLSH.
8=CTSL·RLSL.

MKV852780

CHART 28
REMOTE

lOCAL
9

CHANNELS

U=UNUSED
w

S=SYNC SEE CHART 3

Cl.

A=ASYNC
SW=SWITCHED

>....J
z

STOPBITS

1.15 2

SIGNALS

A - ASSERT
l = l·DIAl
R = R·DIAl
B = 2-DIAl
P = PASS

DATAPAR

N = NONE
0=000
E = EVEN

SPEED

1200

(f)

IIIIIIIII
IIIIII111

2400
4800
9600
AUTOBAUD
OTHER<D
FLOW

NONE

r
u

XO"-'*B

xoN*·C

XO~T

(f)

CTS·RTS

(f)

OTHERCD

«
FllLCHAR

(0-255}

PRIORITY

L-LOW
N=NORMAL
H=HIGH

ECHO
MESSAGES
COMTERM
COMECHO

SWITCHED
E = ENABLE
D = DISABLE
ASYNC
N = NONE
L = LOCAL
R = REMOTE
B = BOTH

AUTODISC

E = ENABLE
D = DISABLE

CHANNEL 10

ATOZ

GROUP ACCESS

ID·lIST

I I I I I I I I I

II I I I I I I I

N = NONE
D = DIAL

(f)

SIGNALS

rJIr= DIA~
A = ASSERT
A*=ASSER-(ii

<D OTHER SPEED SELECTIONS
1 =50. 2=75. 3=110.4=1345. 5=150.
6=300.7=600. (ASYNC ONLY S=SAMEBAUD)
SPlIT·SPEED 8=75 1200 9=1200 75
10=150;2400 11 =2400 150

OTHER FLOW SELECTIONS
1=XON·B .. 2=XON·C. 3=XON· T.
4=DSR·DTR.5=CTSH·RLSH.
6=CTSH·RLSL. 7=CTSl·RLSH.
8=CTSl·RlSl

MKV652792

CHART 3
REMOTE

LOCAL
TYPE

I I

CHANNELS
S = SYNC

D= DDCMP

SPEED

INT 1200

INT 1800
INT 2400
INT 4800
INT 7200
Il.

INT 9600

0
0
.tI

INT 1800

INT 1200

z
>-

INT 2400

(J)

INT 4800
INT 7200
INT 9600

IIIIIIIII

NONE

FLOW

CTS·RTS

BLOCKSIZE

..J

512
1024

I I II II

2048

4096

(J)

DDCMP
ONLY
SYNFILL

2.4.6

CHART 4

GENERAL PARAMETERS'
LOCAL
TIME:

DATE:

00:00 to 23:59
MM·DD·YY

ALARM:

ENABLED
DISABLED

PASSWORD:
USER:
SYSTEM:

o
o

REMOTE

0
0

(8 CHARACTERS MAX.)

MI(V85·2793

APPENDIX E
SIGNAL CHARACTERISTICS
E.l INTRODUCTION
This appendix defines signal characteristics for concentrated link
and individual channels in a DFM system. Pin assignments,
associated signal names, and
usage are covered.
System
configurations and related signal characteristics are divided into
the following groups:
1.

Concentrated Link Signal Characteristics

Channel Signal Interface Characteristics
a.

General

Asynchronous and Switched Channels
1)
2)
3)

4)
5)
6)
7)
8)

ASSERT Mode
PASS Mode
DIAL Mode
DIAL* Mode
ASSERT* Mode
CTS-RTS Flow
DSR-DTR Flow
CTSx-RLSx Flow

Synchronous and DDCMP Channels
1)
2)

No Flow Control
CTS-RTS Flow

E-l

E.2 CONCENTRATED LINK SIGNAL CHARACTERISTICS
The concentrated link between two DFM units may be either a leased
line with modems at each end or a direct connection by means of a
"null modem" crossover cable (BC22L or equivalent). When a
configuration using modems is employed, a straight-through cable
(BC22F or equivalent) should be used to connect the DFM unit to
the modem. Appendix C outlines cable wiring. These cables are
available from Digital Equipment Corporation.
When using synchronous modems, the link speed must be set to sync.
When using asynchronous modems or a direct connection, the 1 ink
speed must be set to async. The async 1 ink speed is 9600 bi ts/s
asynchronous encoded NRZI, and will not work with data-sensitive
asynchronous modems.
The concentrated link connector (see Table E-l)
RS-232-C 25-pin DTE connector.
Table E-1

is a standard

Concentrated Link Signal Characteristics

Direction

Signal Name and Usage

N/A

Protective ground
ground.

From DFM

Transmitted data (TD): bit serial data transmitted by the DFM.

To DFM

Received data: bit serial data received by the
DFM.

From DFM

Request to send (RTS): always asserted by the
DFM during operation. When using a null modem
cable (wi th 1 ink speed set to async), RTS is
connected to CTS at each cable end to indicate
a modem ready condition to the DFM.

To DFM

Clear to send (CTS): indicates that the modem
is ready to accept data from the DFM. Loss of
the CTS to the DFM for an extended period of
time indicates to the DFM that concentrated
link communication has been lost, and the DFM
will attempt to reinitialize the link. When a
BC22L null modem cable is used, RTS is looped
back to assert CTS so that the modem ready
condition will be present.

To DFM

Data set ready (DSR): not used by the DFM.

N/A

S i 9 n a 1 g r 0 un d ( SG): g r 0 un d ref ere n c e for all
other circuits except protective ground (pin

(PG):

connected to chassis

1) •
J9

E-2

Table E-l

Concentrated Link Signal Characteristics (Cont)

Direction

Signal Name and Usage

To DFM

Carrier detect
(CAR):
this signal,
when
asserted by a modem, indicates that the modem
is successfully communicating with another
modem. The DFM moni tors this signal only to
display the state of the signal on the display
panel. When using a BC22L null modem cable,
the signal DTR from each unit is crossed over
to CAR at the other uni t to prov ide the CAR
indicator when a successful connection is
achieved. If this LED is not lit on the front
panel, there is not a successful connection
between the two units.

To DFM

Transmitter signal element timing (TXC): a
modem must supply the synchronous data clocks
for the data on transmitted data, pin 2, when
the DFM is set to link speed synchronous.

To DFM

Receiver signal element timing (RXC): a modem
must supply the synchronous data clocks for
the data on received data, pin 3, when the DFM
link speed is set to synchronous.

From DFM

Data terminal ready (DTR): always asserted by
the DFM during operation. When two DFM units
are connected by a BC22L null modem cable, DTR
at each unit is connected to CAR at the other
un i t to pro v ide a po sit i v e in d i cat ion 0 n th e
front panel CD (carrier detect) LED when a
successful connection is establ ished between
the uni ts.

NOTE
If CTS is off for more than five
seconds, network ready will flash on the
front panel display. If the link is
established, and CTS is OFF for more
than one minute, the link will be
considered lost. The DFM unit will then
attempt to reinitialize and flush all
buffers.

E-3

E.3 CHANNEL SIGNALS INTERFACE CHARACTERISTICS
DFM channels use a standard RS-232-C DCE interface connected by a
25-pin female D-shell connector. Channels are connected to a DTE
terminal or CPU wi th a BC22E or BC22F straight-through cable. A
channel is connected to a modem or another DCE inter face dev ice
with a BC22M crossover cable. When a BC22M crossover cable ia
utilized with the DFM unit, a DTE interface is presented. Appendix
C contains cable configurations and descriptions.
Signals having characteristics that do not vary based on
configuration, are described in this section. Signals with
characteristics dependent on configuration are partially defined
in Table E-2 with more explicit descriptions in the following
sections.
Table E-2

Channel Signal Characteristics -- General

Direction

Signal Name and Usage

N/A

Protec t i ve ground
ground.

To DFM

Transmitted data (TD): bit serial
terminal or attached device to DFM.

From DFM

Received data (RD): bit serial data from DFM
to terminal or attached device.

To DFM

Request to send (RTS): used for CTS-RTS flow
control and pass signals option.

From DFM

Clear to send (CTS): used for CTS-RTS flow
control;
the four CTSx-RLSx flow control
types; and assert, pass, assert*, dial, and
dial* signal options.

(PG):

connec ted

to chass i s
data

from

NOTE
In CTSx-RLSx, x may be either L for low
or H for high.
6

From DFM

Data set ready (DSR): used for DSR-DTR flow
control and assert, pass, assert*, dial, and
dial* signal options.

N/A

Sig nal ground (SG): ground re fe rence fo raIl
other signals except protective ground (pin
1) •

E-4

Table E-2

Channel Signal Characteristics -- General (Cont)

Direction

Signal Name and Usage

From DFM

Carrier detect (CAR): used in CTS-RTS flow
control for synchronous channels only, and
used in assert, assert*, pass, dial, and dial*
signal options.

To DFM

External
transmit
signal
element
timing
(ETXC): when a synchronous modem or device is
used with a channel configured in externally
clocked mode
(speed EXTxxxx),
the device
should
supply
the
clocking
for
pin
2,
transmitted data, on this pin.
NOTE
xxxx is the speed in bits per second
(bits/s) •

To DFM

External receive signal element timing (ERXC):
when a synchronous modem or device is used
with a
channel
configured
in
externally
clocked mode
(speed EXTxxxx),
the dev ice
supplies the clocking for pin 3, received
data, on this pin.

To DFM

Reverse carrier (RCA), also called reverse
line sense (RLS): used for the four CTSx-RLSx
flow control types, PASS, DIAL, and DIAL*
signal options.

From DFM

Transmitter signal element timing (TXC): when
a
synchronous
channel
is
configured
in
internally clocked mode (speed INTxxxx), the
DFM
supplies
the
clocking
for
pin
2,
transmitted data, on this pin.

From DFM

Receiver signal- element timing (RXC): when a
synchronous
channel
is
configured
in
internally clocked mode (speed INTxxxx), the
DFM supplies the clocking for pin 3, received
data, on this pin.

To DFM

Da ta te rm inal ready (DTR): used for DSR-DTR
flow con trol, and pass and assert* signal
options.

E-5

Table E-2

Channel Signal Characteristics -- General (Cont)

Direction

Signal Name and Usage

From DFM

Ri n gin d i cat 0 r ( RI): t his s i g n a l i sal wa y s
deasserted except when the pass signals option
is selected, or when a channel is programmed
as "unused."
When a channel is unused, thi s
pin is asserted. A customer-supplied cable may
be used to connect this pin 22 to pin 25
(busy) on a modem as a "busy out" indication
for that channel.

To DFM

Reverse ring (RRI): used with the pass signals
option.
NOTE
The mInImum interface needed for a
channel
configured
for
asynchronous
operation is transmi tted data (pin 2),
received data (pin 3), and signal ground
(pin 7). More signals may be required
depending on the type of flow control
and signals option selected.

E-6

E.4

SIGNAL CHARACTERISTICS FOR ASYNCHRONOUS AND SWITCHED CHANNEL
TYPES

E.4.l Assert Mode
Table E-3 lists the signal characteristics for a channel when the
signals option is set to assert. Flow control, if selected,
overrides the assert characteristics of these signals.
Table E-3

Assert Mode Signal Characteristics

Direction

Signal Name and Usage

From DFM

Clear to send (CTS): CTS is always asserted in
assert mode.

From DFM

Data set ready (DSR): DSR is always asserted
in assert mode.

From DFM

Carrier detect (CAR): CAR is always asserted
in assert mode.

From DFM

Ring indicator (RI): RI is always deasserted
(log ical false) in assert mode.

E-7

E.4.2 Pass Mode
Table E-4 lists the signal characteristics for a channel when the
signals option is set to pass. Flow control, if selected,
overrides the pass characteristics of these signals.
In the following description:
•

For a switched channel, the -related" channel is the
channel to which this channel is currently connected, and

•

For an async channel, the _ related" channel is
channel with the same number on the other DFM unit.

the

Setting dedicated channels to pass causes both ends to be in pass
mode, and EIA signal changes are relayed in both directions.
Switched channel connections can result in signals being passed in
only one direction.
Example:
Suppose a switched channel with the signal option set to pass
is connected to another that is set to assert.
The asse r t channel end asse rts sig nal s to the connected DTE,
but since it has also been notified (upon connection) that the
related channel is set to pass, it wi 11 pass s ig nal changes
that are detected along to the connected channel.
The pass channel end passes signal changes along to the assert
end, but the changes are not relayed to the connected DTE.
Table E-4

Pass Mode Signal Characteristics

Direction

Signal Name and Usage

To DFM

Request to send (RTS): if the related channel
end is set to pass, the state of this signal
appears as CTS on pin 5 of the related
channel.

From DFM

Clear to send (CTS): the state of this signal
on a channel end set to pass is determined by
the state of RTS (pin 4) on the related
channel. CTS is deasserted on a switched
channel that is set to pass and is not
currently connected to another channel.

E-8

Table E-4

Pass Mode Signal Characteristics (Cont)

Direction

Signal Name and Usage

From DFM

Data set ready (DSR): the state of this signal
on a channel end set to pass is determined by
the s tat e 0 f DT R ( pin 2" ) 0 nth ere 1 ate d
channel. DSR is deasserted on a switched
channel that is set to pass and is not
currently connected to another channel.

From DFM

Carrier detect (CAR): the state of this signal
on a channel end set to pass is determined by
the state of RCA (pin 11) on the related
channel. CAR is deasserted on a switched
channel that is set to pass and is not
currently connected to another channel.

To DFM

Reverse carrier (RCA), (also known as reverse
sense (RLS): if the rela ted channel is
set to pass, the state of this signal is
output as CAR (pin 8) of the related channel.
1 i ne

To DFM

Data terminal ready (DTR): if the related
channel is set to pass, the state of this
signal is output as DSR (pin 6) of the related
channel.

From DFM

Ring indicator (RI): the state of this signal
on a channel end set to pass is determined by
the state of RRI (pin 25) on the related
channel. RI is deasserted on a switched
channel that is set to pass and is not
currently connected to another channel.

To DFM

Reverse ring indicator (RRI): if the related
channel is set to pass, the state of this
signal is output as RI (pin 22) of the related
channel.
NOTE
The characteristics of the input signals
(DTR, RTS, RRI, and RCA) are determined
by the signals option setting for the
other channel.

E-9

E.4.3 Dial Mode
Table E-5 lists the signal characteristics for a channel when the
signals option is set to dial. Note that if any flow control is
selected having conflicting usage for any of the signals, the
result is unpredictable. For example, the dial mechanism may
toggle a signal for a certain reason, only to have it changed by
the flow control mechanism. In general, out-of-band flow control
is not recommended on the channel with the signals option set to
dial.
Table E-5

Dial Mode Signal Characteristics

Direction

Signal Name and Usage

From DFM

Clear to send (CTS): asserted by the DFM after
the DFM detects RCA and DTR raised by the
modem. Indicates to the modem that the DFM is
now ready to beg in normal da ta tr ansmission.
This signal appears as RTS, pin 4, at the
modem end of the cable.

From DFM

Data set ready (DSR): asserted by the DFM
after the DFM detects RI raised by the modem.
It indicates that the modem should go "online." A timer is started and if RCA and DTR
are not both raised within 15 seconds, the
line is considered "off-line" and the DFM
channel will go back to the idle {hung up}
state. This signal appears as DTR, pin 20, "at
the modem end of the cable.

From DFM

Carrier detect (CAR): not supported in the
BC22M cable.
Always deasserted by the DFM
when the dial signal option is selected.

To DFM

Reverse carrier detect (RCA): monitored by the
DFM, and when asserted by the modem (along
wi th DTR) , ind icates tha t the modem is II online." This signal originates on pin 8 (CAR)
at the modem end of the cable. Loss of this
signal during communications on a channel with
the dial signal option selected will cause the
DFM to force the modem "off-line."

To DFM

Data terminal ready (DTR): this signal is
monitored by the DFM, and when asserted by the
modem along with RCA, indicates that the modem
is "on-line." This signal originates on pin 6
(DSR) at the modem end of the cable. Loss of
this signal during communications on a channel
with the dial signal option selected causes
the DFM to force the modem "off-line."

E-10

Table E-5

Dial Mode Signal Characteristics (Cont)

Direction

Signal Name and Usage

To DFM

Reverse ring (RR!): this signal indicates to
the DFM that the phone 1 ine connected to the
modem is "ring ing." The DFM then asserts DSR
and wai ts 15 seconds for the modem to assert
RCA and DTR to indicate that it has successfully gone "on-line." This signal originates
on pin 22 (ring indicator) at the modem end of
the cable.

E-ll

E.4.4 Dial* Mode
Table E-6 lists the signal characteristics for a channel when the
signals option is set to dial*. Note that if any flow control is
selected having conflicting usage for any of the signals, the
result will be unpredictable. Out-of-band flow control is not
recommended for channels with the signals option set to dial*.
Table E-6

Dial* Mode Signal Characteristics

Direction

Signal Name and Usage

From DFM

Clear to send (CTS): this signal is asserted
by the DFM after it detects RCA and DTR raised
by the modem. It ind icates to the modem that
the DFM is ready to beg in normal data
transmission. It is also asserted by the DFM
if a swi tched connec t ion is made to th is
channel from another channel.
The signal
appears on pin 4 (request to send) at the
modem end of the cable.

From DFM

Data set ready (DSR): this signal is asserted
by the DFM after the DFM detects RI raised by
the modem, and indicates that the modem should
go "on-line." When DSR is asserted, a timer is
started. If both RCA and DTR are not asserted
within 15 seconds, the line is considered
"off-line" and the DFM channel will go back to
the idle (hung up) state. This signal is also
raised by the DFM if a switched connection is
made to this channel from another channel.
This assertion will cause a dial-out modem to
go "on-line" and wait for dial commands. Note
that the DFM does not issue any dial commands
to the modem because this is the responsibility of the user. The signal appears on pin 20
(DTR) at the modem end of the cable.

From DFM

Ca r r ie r detect (CAR): Not suppo rted in BC22M
cable. Always deasserted by the DFM when the
dial* signal option is selected.

To DFM

Reverse carrier detect (RCA): this signal is
monitored by the DFM, and when asserted by the
modem along with DTR, indicates that the modem
is "on-line."
Loss of this signal during
communications on a channel with the dial*
signal option selected causes the DFM to force
the modem "off-line." The sig"nal originates on
pin 8 (CAR) at the modem end of the cable.

E-12

Table E-6

Dial* Mode Signal Characteristics (Cont)

Direction

Signal Name and Usage

To DFM

Data terminal ready (DTR): this signal is
moni tored by the DFM, and when raised by the
modem along with RCA, indicates that the modem
is "on-line." Loss of this signal during communications on a channel with the dial* signal
option selected will cause the DFM to put the
modem ·off-line.· This signal originates on
pin 6 (DSR) at the modem end of the cable.

To DFM

Reverse ring (RRI): this signal indicates to
the DFM that the phone 1 ine connected to the
modem is • ring ing.· The DFM then asserts DSR
and wa i ts 15 seconds for the modem to assert
RCA and
DTR
to
indicate
that
it
has
successfully gone ·on-line." It originates on
pin 22 (RI) at the modem end of the cable.

E-13

£.4.5 Assert* Mode
Table E-7 lists the signal characteristics for a channel when the
signals option is set to assert*. Note that if any flow control is
selected having conflicting usage for any of the signals, the
result will be unpredictable.
Table £-7

Assert* Mode Signal Characteristics

Direction

Signal Name and Usage

From DFM

Clear to send (CTS): CTS is always asserted,
except for four seconds when a swi tched connection involving the channel is terminated.
This deassertion indicates to the attached
device that the connection no longer exists
and that a logoff or other suitable action
should be performed.

From DFM

Data set ready (DSR): DSR is always asserted,
except for four seconds when a switched
connection involving the channel is terminated. This deassertion indicates to the attached
device that the connection no longer exists
and that a logoff or other suitable action
should be performed.

From DFM

Carrier detect (CAR): not supported in BC22M
cable. CAR is always asserted, except for"four
seconds when a swi tched connection involving
this channel is terminated. This deassertion
indicates to the attached device that the
connection no longer exists and that a logoff
or other suitable action should be performed.

To DFM

Data terminal ready (DTR): monitored by the
DFM, and when a loss of this signal (true to
false transition) is detected, ,the DFM will
terminate any switched connection in which
this channel is involved. This mechanism may
be used by the attached device to show that
the device is no longer in use, and can be
connected to another switched channel.

From DFM

Ring indicator (RI): RI is deasserted (logical
false).

E-14

E.4.6 Asynchronous CTS-RTS Flow
Table E-8 lists the signal characteristics unique to the CTS-RTS
flow control option for asynchronous channels. If the assert or
pass channel signal option is selected, the usage for CTS-RTS flow
will override the usage described under the signals option
description. If any other channel signal option is selected along
with CTS-RTS flow, the results are unpredictable.
Table E-8

Asynchronous CTS-RTS Signal Characteristics

Direction

Signal Name and Usage

To DFM

Request to send (RTS): the DFM interprets RTS
high as an indication that the connected OTE
can receive data. RTS low is interpreted as a
STOP data signal.

From DFM

Clear to send (CTS): the DFM raises CTS to
signal connected DTE that the DFM can receive
data. The DFM lowers CTS to indicate to the
attached device that it is not ready to
receive data.

E-IS

E.4.7 DSR-DTR Flow
Table E-9 lists the signal characteristics unique to the DSR-DTR
flow control option. If the assert or pass channel signal option
is selected, the usage for DSR-DTR flow wi 11 overr ide the usage
described under the signals option description. If any other
channel signal option is selected along wi th DSR-DTR flow, the
results are unpredictable.
Table £-9

DSR-DTR Signal Characteristics

Direction

Signal Name and Usage

From DFM

Data set ready (DSR): the DFM raises DTR to
indicate to the attached device that it is
ready to receive data. The DFM lowers DSR to
indicate to the attached device that it is not
ready to receive data.

To DFM

Data terminal
ready
(DTR) :
DTR high is
interpreted by the DFM as an indication that
the con n e c ted DT E i s rea d y tor e c e i v e d a t a •
DTR low is interpreted as a STOP data signal.

E-16

E.4.8 CTsx-RLSx Flow
Table E-10 lists the signal characteristics unique to the four
CTSx-RLSx flow control options (x = L for low and H for high). If
the assert or pass channel signal option is selected, the usage
for CTSx-RLSx flow will override the usage described under the
signals option description. If any other channel signal option is
selected along with CTSx-RLSx flow, the results are unpredictable.
Table E-10

CTSx-RTSx Signal Characteristics

Direction

Signal Name and Usage

From DFM

Clear to send (CTS):
CTSH-RLSH and CTSH-RLSL Types
The DFM asserts CTS to indicate to the
attached device that it is ready to receive
data. The DFM deasserts CTS to indicate to the
attached device that it cannot receive data.
CTSL-RLSH and CTSL-RLSL Types
The DFM asserts CTS to indicate to the
attached device that it cannot receive data.
The DFM deasserts CTS to indicate to the
attached device that it is ready to receive
data.

To DFM

Reverse line sense or reverse carrier (RLS):
CTSH-RLSH and CTSL-RLSH Types
The DFM interprets RLS high as an indication
that the connected DTE is ready to receive
data. The DFM interprets RLS low as an indication to stop sending data to the connected
DTE.
CTSH-RLSL and CTSL-RLSL Types
The DFM interprets RLS high as an indication
to stop sending data to the connected DTE. The
DFM interprets RLS low as an indication that
the attached device is ready to receive data.

E-17

E.5

SIGNAL CHARACTERISTICS FOR SYNCHRONOUS AND DDCMP
CHANNEL TYPES

E.5.l No Flow Control
Table E-11 lists the signal characteristics for no flow control
when used with synchronous or DDCMP channels. No flow control
establishes a full-duplex communication with synchronous devices.
Table E-11

Signal Characteristics Without Flow Control

Direction

Signal Name and Usage

From DFM

Clear to send (CTS): in synchronous mode, this
signal is always asserted by the DFM.
In DDCMP mode, this signal is always asserted
unless there is not sufficient buffer space
available to hold the frame. The DFM decodes
the header portion of a frame to determine the
size 0 f a data frame. In DDCMP mode, CTS
cannot be asserted by the DFM until the
concentrated link to the remote unit has been
established.

From DFM

Data set ready (DSR) : DSR is always asserted
by the DFM.

From DFM

Carrier detect
by the DFM.

(CAR) : CAR is always asserted

From DFM

Ring indicator
by the DFM.

(RI) : RI is always deasserted

E-18

E.5.2 Synchronous CTS-RTS Flow
Table E-12 lists the signal characteristics for CTS-RTS flow
control when used with synchronous or DDCMP channels. CTS-RTS flow
control establishes half-duplex communication with synchronous
devices.
Table E-12

Synchronous CTS-RTS Signal Characteristics

Direction

Signal Name and Usage

To DFM

Request to send (RTS): RTS asserted by an
attached device is interpreted by the DFM as
meaning that the device has some data to
transmit to the DFM. If there is empty buffer
space for <BLOCKSIZE> characters (synchronous)
or 32 characters (OOCMP), CTS will be raised
to allow the device to transmit. The DFM does
not transmit data to the attached device while
RTS is asserted. Instead, it raises CTS and
allows the device to transmit, after which the
device should deassert RTS, allowing the DFM
to transmit.

From DFM

Clear to send (CTS): CTS is asserted by the
DFM to allow an attached device to transmi t
data to the DFM. It is normally deasserted,
but will be asserted in response to the
attached device asserting RTS. It will be
deasserted when the attached device completes
sending and drops RTS. The DFM will decode the
header of a data frame to determine if there
is sufficient space for the frame. If there is
insufficient buffer space available for a
frame or block, then CTS is deasserted. In
DDCMP mode, CTS cannot be asserted by the DFM
until the concentrated link to the remote unit
has been established.

From DFM

Data set ready (DSR): DSR is always asserted
by the DFM.

From DFM

Carrier detect (CAR): the DFM asserts this
signal while it is transmitting data to the
attached device. It is deasserted at all other
times.

From DFM

Ring indicator
by the DFM.

E-19

(RI): RI is always deasserted

APPENDIX F
INCOMPATIBILITIES OF SOFTWARE
LEVEL 1.0 WITH LATER RELEASES
F.l INTRODUCTION
DFM software releases subsequent to 1.0 contain features not
available with the 1.0 level. The software release level that is
present appears in the header line of DFM output to the
supervisory terminal.
F.2 HALF-/FULL-DUPLEX DDCMP
Software level 1.0 runs only half-duplex DDCMP. Software level 1.1
can run either half- or full-duplex DDCMP. Half-duplex is selected
by setting the flow control option for that channel to CTS-RTSi
full-duplex is selected by a flow control of NONE for that
channel.
If a uni t wi th software level 1.0 is connected to another wi th
software level 1.1, the software level 1.1 will check that all
DDCMP channels have the flow control option set to CTS-RTS. It
will change any channels with flow control set to NONE to be
CTS-RTS.
With levels 1.0 and 1.1 connected, flow control for DOCMP channels
cannot be set to NONE (selecting full-duplex operation) on either
unit. When attempted, an error message is displayed.
F.3 SATELLITE DELAY
The link satellite delay option setting is handled differently by
units with software level 1.0. Since the handling of frames on the
link is crucial for compatibility of two units, when a software
level 1.0 unit is connected to another unit with a different
software level, the satellite option cannot be used.
F.4 MULTILINE BROADCAST MESSAGES
Only software levels subsequent to 1.0 have the ability to
broadcast a message longer than one line from the supervisory
channel. If a multiline broadcast message is sent from the
supervisory channel of a software level 1.1 unit, only the first
80 characters (I line) of that message will be sent to terminals
connected to a software level 1.0 unit.
F.S INDEFINITE REPEAT
With software level 1.1, an indefinite number of repetitions for
the REPEAT command is invoked with the asterisk (*) in the
repetitions field of the command line. Software level 1.0 units do
not have this feature.

F-l

'.6

ABILITY TO SET A CHANNEL TYPE TO ·UNUSED· WITHOUT LOSING
PARAMETERS
Only software levels subsequent to 1.0 support this feature. On
software level 1.0 units, when a channel type is set to unused,
parameters immediately return to their default values.

With a software level 1.0/software level 1.1 combination, when a
channel type is set to unused, channel parameters will be set to
their defaults on both units. Thus, this feature only appears on a
homogeneous software level 1.1 (or later release) system.
With the software level 1.1 unit in a software level 1.I/software
level 1.1 combination, an unused channel always will display
·UNUSED -- (was UNUSED)- to show that the previous parameters were
not saved.
F.7 SWITCHED CONNECTION FROM SUPERVISORY CHANNEL
When a command is entered to connect a remote channel with another
remote channel, the command is forwarded to the remote uni t and
executed there. A command to connect a remote channel to a group
is also forwarded to the remote unit. All other CONNECT commands:
1.

Connect local channel to local port,

Connect local port to group, and

Connect local channel to remote channel (same as connect
remote channel to local channel),

are executed by the local unit.
Software level 1.0 does not support the capability of connecting
two swi tched channels from the supervisory channel. When a 1.0
unit is connected to a later release unit, and such a command is
entered, it will succeed only if it is to be performed by the 1.1
(or later release) unit. Any command that must be forwarded to the
1.0 unit will not succeed, and the error message -Request Not
Supported on Remote Unit- will be displayed.
F.S GROUP -NAMES·
Only software levels subsequent to level 1.0 allow a fivecharacter descriptive name to be assigned to switched channel
groups (that are defined by a letter). Names can be neither
entered or displayed on a software level 1.0 unit.
F.9 SYSTEM WARNING FOR COMMANDS THAT RESTART THE SYSTEM
Warning occurs only with software levels 1.1 and later.

F-2

F.1e

ABILITY TO SET SPEEDS SEPARATELY FOR EITHER END FOR
SYNCHRONOUS CHANNELS
With software level 1.1 and later releases, local and remote
speeds are set independently (I-speed and r-speed options) for
synchronous channels. With software level I.e, only "speed" can be
set for synchronous channels; this sets both local and remote ends
of the channel.
When software level 1.0 is connected to a software level 1.1 unit,
setting ei ther the I-speed or r-speed option for a synchronous
channel results in both options being set to the same value.
When the two uni ts are fi rst connected, the software level 1.1
unit will set all remote speeds on sync channels to the current
setting for the I-speed option.
On a 1.0 and 1.1 combination, the full range of external speeds
appears only on the 1.1 uni t. Selecting any of them for ei ther
channel end results in both channel ends (since they are both set
with a 1.0 and 1.1 combination) being set to "external."
F.11 ADDITIONAL ASYNCHRONOUS CHANNEL FLOW CONTROL SELECTIONS
Software levels 1.1 and later contain selections for flow control
on asynchronous channels that are not available on I.e units.
When a software level 1.0 uni t is connected to a software level
1.1 unit, the software level 1.1 unit will check all asynchronous
channel flow types. If the flow is not "NONE," "XON-B," or
"CTS/RTS" (1.0 selections), the unit will set the flow control
option for that channel to "NONE."
When a unit with 1.0 software is connected to another with a later
release, any attempt to set the flow control (on either unit) to a
value other than those supported by the 1.0 unit will not succeed
and an error message will be displayed.
F.12 SWITCHED CHANNEL "DIAL-UP· OPTION NOW CALLED ·SIGNALS·
In addition to changing the name of the option, additional values
are available with the 1.1 and later release software. The
switched channel dial-up option for I.e units can only be set to
either ENABLED or NONE. The signals option has additional values
of assert, assert*, pass, dial, and dial*. (Dial corresponds to
enabled.)
Thus, the signals option for switched channels may only be set to
either DIAL or NONE when a 1.0 unit is connected to a unit with a
later software release.

F-3

F.13 COMMAND CHARACTER (COMCHAR)
The command character sequence for 1.9 units is IB18 (hex), and it
is lClC (hex) for software level 1.1 and later. Hex lC corresponds
to the CONTROL/BACKSLASH sequence on DIGITAL terminals, and 18 is
the ESCAPE key.
When a 1.9 unit is connected to a 1.1 or later revision, the first
time down-line loading of parameters occurs, the valid or master
unit will load its selection for this option on the other unit.

F-4

INDEX

Abbreviated commands, 1-6, 6-11
Alarm messages, 6-34
Assigning group IDs, 4-4, 4-10
Asynchronous, 2-2, 3-27, 4-1, 4-8, 6-29, 6-31 through 6-36
options, 6-31 through 6-36
autobaud, 6-31
comecho, 6-36
comterm, 6-35
data parity, 6-31
echo, 6-34
fillcharacter, 6-33
flow control, 6-31
I-speed, 6-31
messages, 6-34
priority, 6-33
r-speed, 6-31
samebaud, 6-31
signals, 6-32
split-speed, 6-31
stopbits, 6-32
Autobaud, 1-7, 6-31, 6-36
Autodisconnect, 1-4, 1-6, 6-17, 6-44
disabled, 6-17
enabled, 6-17
Automatic self-test, 7-2
B

Bandwidth factor, 2-6, 2-7
Benchtest, 2-9, 3-1, 3-18, 3-25
Blinking DR indicator, 7-8
Blocksize, 6-45
Break character control, 1-7
Broadcast, 3-30, 5-5, 6-34, A-I
Buffer overflow, 6-25
Busy, 2-3
C

Cables, 2-10, 2-11, 3-29, Appendix C
BC22E, C-2
BC22F, C-3
BC22L, C-4
BC22M, C-5
special signals, C-6
Cancel, 5-6

INDEX-l

Carrier detect, 2-4, 3-21, 3-29, 6-9, 7-8
CO indicator, 6-9, 7-8 through 7-25
Channel all programming, 6-11
Channel command prompt, 3-24, 3-27, 3-28, 4-7, 4-8, 4-11, 4-12,
4-13, 5-9, 5-10, 5-12, 5-13, 5-29, 5-30, 5-31
Channel configuration pitfalls, 7-28
Channel contention, 1-11, 1-12, 1-13, 2-2, 6-29
Channel errors, 7-30
buffer overflow, 7-30
data overrun, 7-30
framing errors, 7-30
parity errors, 7-27
Channel expansion, 3-29, 3-31
Channel 10, 2-2, 4-4 through 4-11, 6-35
Channel loopback, 1-8, 7-28 through 7-36
Channel monitoring, 5-16, 5-18, 7-29
Channel operator commands, 3-25
connect, 5-2
disconnect, 5-2
exit, 3-25, 5-2
status, 3-25, 5-2
supervisor, 3-25, 5-2
termtest, 3-25, 5-2
echo, 3-25
pattern, 3-25
Channel parameters, 1-5, 3-24, 3-26, 4-4, 4-5, 4-6, 4-10, 4-11
comecho, 4-10
comterm, 4-10
flow control, 4-4, 4-5, 4-10
group access, 4-4, 4-5, 4-10
10, 4-4, 4-5, 4-10
speed, 4-4, 4-5, 4-10
type, 3-25, 4-4, 4-5, 4-10
Channel signal characteristics, E-3 through E-14
asynchronous/switched, E-5 through E-12
assert, E-7
assert*, E-14
CTS-RTS, E-15
CTSX-RLSX, E-17
dial, E-10
dial*, E-12
OSR-OTR, E-16
pass, E-8
synchronous/OOCMP, E-12 through E-14
CTS-RTS, E-19
no flow control, E-18
Channel signals test, 7-30 through 7-33
EIA signal, 7-33
Channel state indicators, 5-28
Channel switching, 1-4, 1-11, 2-2, 3-25
Channel testing, 7-8, 7-28

INOEX-2

Channel type, 2-2, 6-2, 6-13, 6-28, 6-29, A-2
asynchronous, 2-2, 6-28, 6-29, A-2
OOCMP, 2-2, 6-28, 6-29
switched, 2-2, 6-28, 6-29, A-2
synchronous, 2-2, 6-28, 6-29, A-2
unused, 2-2, 6-28, 6-29
Clear command, 5-7
Clear to send, 2-3
Comchar, 5-2, 6-19, 6-41
command mode, 6-19
control-backslash, 6-19, 5-2, 5-26
Comecho, 3-24, 3-26, 5-2, 5-26, 6-2, 6-14, 6-19, 6-36, 6-41
Comma, 6-4, 6-5
Commands, 5-1 through 5-33
Communications protocol, 2-3
Comterm, 3-24, 3-26, 5-2, 5-26, 6-2, 6-14, 6-19, 6-36, 6-41
Configuration, 3-28, 3-29, 6-16, 6-17
invalid, 6-16, 6-17
valid, 6-16, 6-17
Configuration options, 6-1
Configuration Worksheet, 3-31, 4-13, 6-1 through 6-8, D-1
channel, 6-2, 6-23, 6-28
autodisconnect, 6-2, 6-44
blocksize, 6-2, 6-45
comecho, 6-2, 6-41
comterm, 6-2, 6-41
datapar, 6-2, 6-31
echo, 6-2, 6-34, 6-40
fi11character, 6-2, 6-33, 6-39
flow, 6-2, 6-31, 6-37, 6-45
group access, 6-2, 6-41
10, 6-2, 6-41
messages, 6-2, 6-34, 6-40
priority, 6-2, 6-33, 6-40
signals, 6-2, 6-32, 6-37
speed, 6-2, 6-31, 6-36, 6-44
stopbits, 6-2, 6-31
synfi1l, 6-2, 6-45
type, 6-2, 6-28
general, 6-1
alarm, 6-2, 6-10, 6-13
date, 6-2, 6-10, 6-13
group, 6-2, 6-10, 6-13
password, 6-2, 6-10, 6-13
time, 6-2, 6-10, 6-13
link, 6-2, 6-22
delay, 6-2, 6-23
speed, 6-2, 6-22
system, 6-2, 6-16
autodisconnect, 6-2, 6-17
comchar, 6-2, 6-19
configuration, 6-2, 6-16
default, 6-2, 6-21
name, 6-2, 6-16

INDEX-3

sW-datapar, 6-2, 6-1S
sw-signa1s, 6-2, 6-lS
sw-stopbits, 6-2, 6-lS
type, 6-2, 6-16
Connect, 4-7, 4-12, 5-S, 5-9, 6-41, 6-42
Contro1-backslash, 3-23, 3-2S, 4-S, 5-2, 6-19
Control module, 3-3, 3-6 through 3-11
Copy, 3-25, 3-27, 4-5, 4-10, 4-11, 5-11, 6-12
Co un t e r s, 3 - S
date, 3-S
status, 3-S
time, 3-S
CTS-RTS, 2-3, 6-26, 6-2S, 6-29, E-11, E-13
CTSH-RLSH, 6-26
CTSH-RLSL, 6-26
CTSH-RLSH, 6-26
CTSH-RLSL, 6-26
CTSL-RLSH, 6-26
CTSL-RLSL, 6-26
D

Data channel command, 3-24, 5-1, 5-2, 5-3
asynchronous, 5-2
exit, 5-2, 5-14
supervisor, 5-2, 5-30
termtest, 5-2, 5-31
swi tched, 5-2
connect, 5-2, 5-S, 5-9, 5-10
disconnect, 5-2, 5-12, 5-13
exit, 5-2,5-14
status, 5-2, 5-29
supervisor, 5-2, 5-30
termtest, 5-2, 5-31
Data pattern, 7-9
Data terminal ready, 2-4, 3-13, 3-14, 3-15
DDCMP, 1-4, l-S, I-IS, 2-2, 2-3, 2-13, 6-11, 6-12, 6-29, 6-30
b10cksi ze, 6-45
synfil1, 0-2, 6-15, 6-45
DECmate, 4-3, 4-4, 4-S, 4-10, 4-12, 4-13
Dedicated connection, 4-2
Default, 3-20, 3-2S, 4-9, 6-9, 6-21
Device ready, 3-10, 3-11, 3-21, 3-29, 7-S
DF124, 8-4 through 8-S
DF126, 8-9 through 8-13
DF127, 3-30, 8-14 through 8-24
DF129, 3-30, 8-26 through 8-34
Dial-up modems, 1-7, 2-4, 6-24
Dimensions, A-4
Direct connection, 3-2S, 3-29
Disconnect, 2-3, 3-19, 3-27, 3-2S, 4-S, 5-12, 5-13, 6-17
Down-line loading, 1-5, 6-9, 6-16, 6-17, 7-3
DR, 6-9
DSR-DTR, 6-26

INDEX-4

Echo, 6-34, 6-40, 7-30
local, 7-30
remote, 7-30
EIA signals, 1-5, 6-23, 6-26, 7-26, 7-33, A-3
Enclosure, 3-1, 3-2
Error message, 3-10, 7-6, 7-9, 7-12, 7-13, 7-30, 7-34, 7-35
1inkdrop, 7-12
receive, 7-12
transmit, 7-12
Exit, 3-24, 3-27, 5-14
Expansion memory, 7-6, 7-7
External link modems, 3-28, 3-29
F

Fillcharacter, 6-33, 6-39
Flow control, 1-7, 2-3, 2-6, 2-7, 3-24, 3-26, 6-25, 6-31, 6-37,
6-45, A-3
CTS-RTS, 6-31, 6-37
CTSH-RLSH, 6-31, 6-37
CTSH-RLSL, 6-31, 6-37
CTSL-RLSH, 6-31, 6-37
CTSL-RLSL, 6-31, 6-37
DSR-DTR, 6-31, 6-37
none, 6-31, 6-37
Xon*-B, 6-31, 6-37
XO'n*-C, 6-31, 6-37
Xon*-T, 6-31, 6-37
Xon-B, 6-31, 6-37
Xon-C, 6-31, 6-37
Xon-T, 6-31, 6-37
Flyback (FILL) character delay, 1-7
Front panel, 3-1, 3-6
LEDs, 3-6, 3-9 through 3-17
pushbutton switches, 3-6, 3-7, 3-8, 3-17
Full-duplex, 2-3, 2-6, 6-29, 6-30
G

Group, 1-4
Group access, 2-2, 6-41, 6-42, 6-43, A-2
Group 10, 4-4, 4-5, 4-6, 4-8, 4-10, 4-11, 6-41, 6-42, 6-43
Group names, 4-4, 4-7, 4-12, 6-10, 6-41, 6-42, 6-43
H

Half-duplex, 2-4, 2-6, 6-29, 6-30
Hardware selection guide,. 2-12 through 2-15
Header line, 3-19, 3-23

INDEX-5

Identification decal, 3-1, 3-2, 3-3
In-band, 6-25, 6-27
Indicators, 3-9 through 3-16
carrier detect, 3-9, 3-15
channel data error, 3-9
device ready, 3-9
network ready, 3-9
receive ARQ, 3-9
receive data, 3-9, 3-15
send ARQ, 3-9
send data, 3-9, 3-15
Inspection, 3-1
Installation, 3-28
Integral modem, 1-6, 1-9, 2-8, 2-14, 3-3, 3-6, 3-13 through 3-17,
3-28, 3-29, 3-30, 8-2
Invalid, 3-10, 3-29, 6-9
L

Leased line, 2-4, 2-5
LED error codes, 1-8, 7-2, 7-4 through 7-7, 7-33 through 7-36
LED indicators, 3-9 through 3-16
carrier detect, 3-9, 3-15
clear to send, 3-15
fallback, 3-15
high speed, 3-16
modem ready, 3-9
off hook, 3-15
receive data, 3-9, 3-15
request to send, 3-15
send data, 3-9, 3-15
signal quality, 3-15
terminal ready, 3-9
test mode, 3-15
Link, 2-4 through 2-9, 2-14, 2-15, 3-4, 3-20, 3-29, 7-8
Link bandwidth, 2-5, 2-6, 2-7
Link connections, 8-2, 8-3, 8-4
integral modem, 8-2, 8-4
standalone modem, 8-2, 8-3
Link delay, 6-23
normal, 6-23
satellite, 6-23
Link error counters, 1-5
Link loopback, 1-8, 3-7, 7-9, 7-10 through 7-13
end-to-end, 7-10, 7-11, 7-12
local analog loopback, 7-22 through 7-25
remote analog loopback, 7-18 through 7-21
remote digital loopback, 7-14 through 7-17

INDEX-6

Link modems, 8-1, 8-2
DF124, 8-1
DF126, 8-1
DF127, 8-1
DF129, 8-1
Link signal characteristics, E-l, E-2, E-3
Link signals test, 7-10, 7-26
Link speed, 2-5, 2-6, 2-7, 3-29, 3-29, 6-9, 6-22
async, 3-20, 3-29, 6-9, 6-22
sync, 3-29, 3-29, 6-9, 6-22
Link state indicators, 5-28
Link type, 2-4
LN03 printer, 4-3, 4-5
Local echo, 1-8, 7-22 through 7-25
Logging out, 3-18, 3-21, 3-24, 4-7, 4-11, 5-15
Logon password prompt, 4-8, 4-11, 5-1, 5-15

M
Manual Iback, 3-7, 7-11, 7-12
Manual maintenance mode, 1-8, 7-1
Master, 3-10, 3-29, 3-23, 6-9
Memory error status, 7-5, 7-6, 7-7
Message option, 3-19, 3-39, 5-5
Microwave links, 2-5
Model number, 3-3
Modem options, Appendix 8
DF124, 8-5 through 8-9
DF126, 8-10 through 8-14
DF127, 8-15 through 8-24
DF129, 8-25 through 8-34
Modem speed 1-9, 8-1
2409 bits/s, 1-9, 8-1
4800 bits/s, 1-9, 8-1
9600 bits/s, 1-9, 8-1
Modems, 4-9, 4-19, 6-24
Monitor, 1-5, 5-16, 5-17, 5-18, 7-1, 7-28, 7-29, A-I
MS-DOS, 4-11, 4-12

N
Name, 6-16, 6-43
Network ready, 3-9, 3-21, 3-29, 6-9, 7-1, 7-5, 7-6, 7-8
Nonvolatile storage, 1-6
Null modern, 2-14, 3-18, 3-21, 3-29

o
Out-of-band, 6-25, 6-26

INDEX-7

Parameter protect, 1-6, 3-8
Parameter saved, 3-24, 4-4, 4-5, 4-10, 4-11
Password, 1-6, 3-18, 3-19, 3-25, 5-1, 5-2, 5-23
system, 1-6, 3-19, 5-1
user, 1-6, 3-19, 5-1
Password prompt, 3-18
Pattern test, 1-8, 5-31, 5-32, 7-28, 7-30, 7-32
poly-COM, 4-11
Port contention, 1-4, 1-11, 1-12
Power supply module, 3-2, 3-3
Power-up self-test, l-S, 3-7, 3-S, 3-16, 3-lS
Priority, 6-33, 6-40
programmable configuration options, 1-4, 6-1 through 6-45
Pushbutton switches, 3-7, 3-S, 3-11 through 3-14, 3-17
Q

Question mark, 6-10
Queued, 1-4, 4-7, 6-42
R

Rainbow, 4-3, 4-5, 4-7, 4-S, 4-10, 4-11, 4-12, 4-13
Rear panel connectors, 3-4, 3-5
data channel connectors, 3-4
link connector, 3-4
power connector, 3-4
supervisory channel connector, 3-4
Reinitialize, 3-20, 3-21, 4-9, 7-3
Remote echo, I-S, 7-9 through 7-21
Repeat, 5-20
Reset, 6-17
Restart, 5-21

s
Satellite links, 1-17, 6-23
SEL) prompt, 3-24, 3-27, 3-2S, 4-7, 4-S, 4-12, 4-13
connect, 3-19, 3-27
disconnect, 3-19, 3-27
exit, 3-24, 3-27
(or "'Y), 3-27
status, 3-27
supervisor, 3-19, 3-24, 3-27
termtest, 3-24, 3-27
Selective modem control, 1-6
Self-test, l-S, 3-7, 3-S, 3-16, 3-18, 3-31, 7-2 through 7-7
Semicolon, 6-10
Serial number, 3-3

INDEX-S

Set, 4-4, 4-5, 4-9, 4-10, 4-11, 5-22
Set command, 5-22, 5-23, 5-24, 6-2, 6-10
alarm, 6-2, 6-10, 6-13
date, 6-2, 6-10, 6-13
group, 6-2, 6-10, 6-13
password, 6-2, 6-10, 6-13
time, 6-2, 6-10, 6-13
Set date, 3-23
Set time, 3-23
Setting multiple options, 6-10, 6-11
Show channel command, 3-24, 3-26, 4-2, 4-5, 4-6, 4-11, 5-25, 5-26,
5-27
Show group, 6-43
Show 1 ink, 6-23
no clock, 6-23
Show system, 3-23
Signals, 6-23, 6-32, 6-37
assert, 6-32
assert·, 6-37
dial, 6-32, 6-37
dial·, 6-37
I-dial, 6-32
pass, 6-32
r-dia1, 6-32
Slave, 3-10, 3-21, 3-29, 6-9
Space, 6-10
Speed conversion, 1-7
Speeds, A-3
Standalone modem, 8-2
Status, 3-27, 3-28, 5-29
Stopbits, 6-18, 6-32
echo, 6-34
fi11character, 6-33
messages, 6-34
priority, 6-33
signals, 6-18, 6-32, 6-37
assert, 6-18, 6-32, 6-37
I-dial, 6-32
pass, 6-18, 6-32, 6-37
r-dial, 6-32
2-dia1, 6-32, 6-37
Supervisor command, 5-1, 5-30
Supervisor password, 2-2
Supervisory command channel, 1-5, 2-1, 2-14, 3-18, 3-19, 3-25,
4-3, 5-1, 5-2, A-I
Switched channel, 1-4, 1-11, 3-25, 3-26, 4-1, 4-2, 4-7, 4-8, 6-29,
6-36
data-par, 6-18, 6-31
signals, 6-18, 6-32, 6-37
assert, 6-18, 6-37
assert·, 6-37, 6-39
dial, 6-37, 6-38
dial·, 6-37, 6-38

INDEX-9

none, 6-37
pass, 6-18, 6-37
speed, 6-36
autobaud, 6-36
split-speed, 6-36
stopbits, 6-18, 6-32
Switches, 3-7, 3-8, 3-11 through 3-14, 3-17
data/talk, 3-14, 3-17
digital loop, 3-14, 3-17
disable modem, 3-14, 3-17
fallback, 3-14, 3-17
fallback speed, 3-14, 3-17
high speed, 3-14, 3-17
local loop, 3-14, 3-17
maintenance, 3-7
remote loop, 3-14, 3-17
self-test, 3-14, 3-17
test pattern, 3-14, 3-17
Synchronous, 1-4, 1-9, 1-11, 1-18, 2-3, 2-13, 2-15, 5-1, 6-11,
6-12, 6-44, 6-45
channels, 1-9, 1-18
external clocking, 6-44
flow control, 6-45
internal clocking, 6-44
speed, 6-44
I-speed, 6-44
r-speed, 6-44
SYS> prompt, 3-19 through 3-28
System configuration, 3-21
invalid, 3-21, 3-23, 3-29
valid, 3-21
System level commands, 3-19
broadcast, 3-19, 5-2, 5-3, 5-5
cancel, 3-19, 5-2, 5-3, 5-6
clear, 3-19, 5-2, 5-3, 5-7
connect, 3-19, 5-2, 5-3, 5-8, 5-9, 5-1~
copy, 3-19, 5-2, 5-3, 5-11
disconnect, 3-19, 5-2, 5-3, 5-12, 5-13
logout, 3-19, 5-2, 5-3, 5-15
monitor, 3-19, 5-2, 5-3, 5-16 through 5-19
(or y ), 3-19, 5-2, 5-3
repeat, 3-19, 5-2, 5-3, 5-2~
restart, 3-19, 5-2, 5-3, 5-21
set, 3-19, 5-2, 5-3, 5-22, 5-23, 5-24
show, 3-19, 5-2, 5-3, 5-25, 5-26, 5-27
test, 3-19, 5-2, 5-3, 5-32, 5-33
System parameters, 3-23, 6-13
autodisc, 3-23, 6-13
comchar, 3-23, 6-13
config, 3-23, 6-13
name, 3-23, 6-13
sW-datapar, 3-23, 6-13
sw-signals, 3-23, 6-13
A

INDEX-10

sw-stopbits, 3-23, 6-13
type, 3-23, 6-13
System reset, 3-8, 7-3
system type, 3-21, 3-29
master, 3-21
slave, 3-10, 3-21, 3-29
T

Tail circuits, 1-11, 1-14
Termtest, 5-31
Test, 5-32, 5-33
Test features, 7-1
test command, 5-32, 5-33, 7-1
Time-out, 1-4, 6-17
Troubleshooting, 7-1 through 7-36
channel, 5-18, 7-2, 7-8, 7-28 through 7-36
link, 5-17, 7-2, 7-8 through 7-27
monitor command, 5-16 through 5-19, 7-1, 7-28, 7-29
system, 5-16
Type, 6-16
master, 6-16
slave, 6-10
U

Unpacking, 3-1
Unswitched channels, 4-1
asynchronous, 4-1
DDCMP, 4-1

synchronous, 4-1
Unused, 4-5, 4-6
User level commands, 3-19, 5-2
logout, 3-19, 5-2, 5-15
monitor, 3-19, 5-2, 5-16 through 5-19
(or . . y), 3-19, 5-2
repeat, 3-19, 5-2, 5-20
show, 3-19, 5-2, 5-25, 5-26, 5-27
User password, 2-2, 5-1
User prompt, 3-19, 5-1

v
Valid entries, 4-7, 4-12, 5-3
VAX computer, 4-3, 4-3, 4-7, 4-8
Voice-grade lines, 2-5

INDEX-II

Warning message, 3-20, 4-9
Weight, A-4
WPS ex communications, 4-3

x
Xon-B, 6-26, 6-27, 6-28
Xon*-B, 6-26, 6-27, 6-28
Xon-C, 6-26, 6-27, 6-28
Xon-T, 6-26, 6-27, 6-28

INDEX-12