Digital PDFs

EK-DSRVX-IC-A01

May 1997

204 pages

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Document:	DECserver 900MC Installation and Configuration
Order Number:	EK-DSRVX-IC
Revision:	A01
Pages:	204
Original Filename:	dsrvxica.pdf

OCR Text

DECserver 900MC
Installation and Configuration
Part Number: EK-DSRVX-IC. A01

February 1997

This manual describes how to install and configure the DECserver 900MC.
Revision/Update Information:

This is a new document.

Digital Equipment Corporation makes no representations that the use of its products in the manner
described in this publication will not infringe on existing or future patent rights, nor do the descriptions
contained in this publication imply the granting of licenses to make, use, or sell equipment or software in
accordance with the description.
Possession, use, or copying of the software described in this publication is authorized only pursuant to a valid written
license from Digital or an authorized sublicensor.
© Digital Equipment Corporation 1997. All rights reserved. Printed in U.S.A
The following are trademarks of Digital Equipment Corporation: clearVISN, DEC, DEChub, DECserver,
OpenVMS, ThinWire, ULTRIX, VAX, VMS, and the DIGITAL logo.
The following are third-party trademarks:
AT&T is a registered trademark and ST is a trademark of American Telephone and Telegraph Company.
Microcom is a trademark of Microcom, Inc.
MS-DOS is a registered trademark of Microsoft Corporation.
Novell and IPX are registered trademarks of Novell, Inc.
All other trademarks and registered trademarks are the property of their respective holders.
FCC Notice — Class A Computing Device:
This equipment generates, uses, and may emit radio frequency energy. The equipment has been type
tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of FCC rules,
which are designed to provide reasonable protection against such radio frequency interference.
Operation of this equipment in a residential area may cause interference in which case the user at his own
expense will be required to take whatever measures may be required to correct the interference. Any
modifications to this device - unless expressly approved by the manufacturer - can void the user’s
authority to operate this equipment under part 15 of the FCC rules.
VCCI Notice — Class 1 Computing Device:
This equipment is in the 1st Class category (information equipment to be used in commercial and/or
industrial areas) and conforms to the standards set by the Voluntary Control Council for Interference by
Data Processing Equipment and Electronic Office Machines aimed at preventing radio interference in
commercial and/or industrial areas. Consequently, when used in a residential area or in an adjacent area
thereto, radio interference may be caused to radios and TV receivers. Read the instructions for correct
handling.
CE Notice — Class A Computing Device:

Warning!
This is a Class A product. In a domestic environment, this product may cause radio interference, in which
case the user may be required to take adequate measures.

Achtung!
Dieses ist ein Gerät der Funkstörgrenzwertklasse A. In Wohnbereichen können bei Betrieb dieses Gerätes
Rundfunkstörungen auftreten, in welchen Fällen der Benutzer für entsprechende Gegenmaßnahmen
verantwortlich ist.
Avertissement!
Cet appareil est un appareil de Classe A. Dans un environment résidentiel cet appareil peut provoquer des
brouillages radioélectriques. Dans ce cas, il peut être demandé à l'utilisateur de prendre les mesures
appropriées.

Contents

Preface
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Purpose of This Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Organization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .x
Conventions and Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Terms Used in This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Associated Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xii
Correspondence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv
Documentation Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv
Online Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv
How to Order Additional Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xv

Safety
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xvii

1 Product Introduction
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
In This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
What is the DECserver 900MC? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Hot Swap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Configuration and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Protocols and Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Special Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

iii

2 Installing the Module
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
In This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Module Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Front Panel Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Back Panel Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
How to Install the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Task 1: Compare the Power Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Task 2: Seat the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Task 3: Verify Initial LED Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Task 4: Connect Port Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11

3 Installing the Setup Port Cable
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
In This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Signaling Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Setup Port Device Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Connecting the Setup Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

4 Configuring the Module in a DEChub 900
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
In this Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
DEChub 900 MultiSwitch INSTALLATION MENU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
[5] Start Redirect Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Using Menus to Configure the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
[1] Reset with Factory Defaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
[2] Reset with Current Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
[3] Show Current Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
[4] Configure IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
[1] Set SNMP Read/Write Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
[2] Set In-Band Interface IP Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

5 Installing Flash RAM
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
In This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Inserting the Flash RAM Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Booting the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

6 Configuring the Modem Ports Using the Access Server
Manager
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
In This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
Adding the DECserver 900MC to the Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Configuring the Modem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Setting Modem Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Sending Commands to the Modem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Upgrading Modem Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Changing the Country Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

7 Configuring the Modems Ports Using the Console
Commands
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
In This Chapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
Setting the Country Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Displaying the Current Country Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Setting the Country Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Logging Out Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Logging Out a Port and Resetting Port Characteristics to Factory Defaults . . . . . . . . . . . . . 7-4
Logging Out a Port and Sending a Reset Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Communicating With the Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

8 Removing the Module
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
In This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1
Removing the Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
Unseating the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

A Problem Solving
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
In This Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
LED Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2
Module LED States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2
Port LED States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3
Normal Powerup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4
Problem Solving Using the LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
Problem Solving Using the Seven-Segment Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-9
Troubleshooting Tips When Using Your Built-in Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-11

B Connector and Cable Assignments
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
In This Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Compatible Cables for the Console Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
8-Pin MJ Console Connector Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
8-Pin MJ Telephone Connector Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

C Product Specifications
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
In This Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Product Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2
Acoustical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3
Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4

D Microcom Networking Protocol
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-1
In This Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-1
MNP Class 10 and MNP Class 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-2
Other Classes of MNP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-3

E Regulatory Requirements
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
In This Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Regulatory Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2
Information Requested by the Telephone Company . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-3
Canadian Department of Communications Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-4
Canadian EMI Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-5

F AT Commands
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-1
In This Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-1
AT Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-2
Commands to Change or Read Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-62
Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-63

vii

Figures
2-1 Front Panel LEDs and Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2-2 Back Panel Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
2-3 Power Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
2-4 Seating the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
2-5 Connecting the Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
3-1 Setup Port Cabling Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
5-1 Inserting the Flash RAM Card. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
8-1 Removing the Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
8-2 Unseating the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
A-1 Seven-Segment Display Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-10
B-1 8-Pin MJ Description for Console Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
B-2 8-Pin MJ Description for Modem Ports. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4

Glossary
Tables
2-1 Front Panel Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2-2 Back Panel Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
7-1 Country Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
A-1 Module LED States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2
A-2 Port State LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3
A-3 Problem Solving Using the LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
B-1 Compatible Cables for DECserver 900MC Console Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
B-2 DECserver 900MC Console Port Pin Assignments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
B-3 DECserver 900MC Modem Port Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
C-1 Product Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2
C-2 Acoustics - Declared values per ISO 9296 and ISO 7779 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3
C-3 Schallemissionswerte Werteangaben nach ISO 9296 und
ISO 7779/DIN EN277792
C-3
C-4 Connectors for the DECserver 900MC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-4
D-1 MNP Class 10 and MNP Class 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-2
D-2 Other MNP Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-3
E-1 Regulations for United States and Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2

viii

Preface

Overview
Purpose of This Document
This manual describes how to install, configure, and use the DECserver 900MC
module. It also provides problem solving, connector and cable assignments, product
specifications, AT commands, and information on the Microcom Networking Protocol
(MNP).

Intended Audience
This manual is intended for use by personnel who will install, configure, and use the
DECserver 900MC.

Organization
This manual is organized as follows:

Section

Description

Chapter 1

Provides an overview of the DECserver 900MC module and
describes its features.

Chapter 2

Provides instructions for installing the DECserver 900MC
module in a DEChub 900 MultiSwitch.

Chapter 3

Provides instructions for installing the setup port on the
DECserver 900MC.

Chapter 4

Provides configuration information when the module is
installed in a DEChub 900 MultiSwitch.

Chapter 5

Provides information on how to install Flash RAM.

Chapter 6

Provides information on how to configure the module’s
built-in modems using the Access Server Manager.

Chapter 7

Provides information on how to configure the module’s
built-in modems using console commands.

Chapter 8

Provides information on how to remove the module from the
DEChub 900 MultiSwitch.

Appendix A

Provides installation-specific problem solving information
using the LEDs and seven-segment display. In addition, it
contains general modem use problem solving information.

Appendix B

Provides connector and pin assignment information.

Appendix C

Provides product specifications for the DECserver 900MC.

Appendix D

Provides information on the Microcom Networking Protocol
(MNP).

Appendix E

Provides information on regulatory requirements.

Appendix F

Provides information on the AT command set, including
command syntax and a description of each command.

Glossary

Lists pertinent terms and their definitions.

Conventions and Terms
Overview
This book uses the following conventions.
Convention

Description

Special Type

This special type in examples indicates system
output.

Boldface

Boldface type in examples indicates user input.

Indicates that you should press the Return key.

Terms Used in This Manual
This book uses the following terms:
Term

Definition

Ethernet

DIGITAL’s term for its product compatibility with ISO
8802-3/ANSI/IEEE 802.3 standards and the Ethernet
standards for CSMA/CD local area networks (LANs).

SNMP

Simple Network Management Protocol, an industry
standard protocol for network management.

Associated Documents
The following documents provide related information about the module. For
information on how to order additional documentation, see the ordering information
provided in this preface.

xii

Title and Order

Description

DEChub 900 MultiSwitch
Owner’s Manual

Provides installation, use, security, and
troubleshooting information for the
DEChub 900 MultiSwitch.

DEChub ONE Installation

Provides installation and operation
guidelines for single-slot hub
configuration, including rack-mount
options and cabling.

DECserver Network Access
Software Installation or
DECserver Network Access
Server Getting Started

Provides information on how to install
the operational software for DECserver
modules on systems running the
Windows 95, Windows NT, OpenVMS,
Digital UNIX, ULTRIX, or UNIX
operating systems.

Network Access Server
Command Reference

Provides information on the usage and
syntax of commands for various network
access servers.

Network Access Server
Management

Provides the procedures to perform
management tasks on various network
access servers.

Network Access Server
Problem Solving

Provides problem-solving procedures
and tools for various network access
servers.

Title and Order

Description

clearVISN Installation

Provides pre- and post-installation
information, as well as actual installation
procedures for each application.

clearVISN Product
Overview

Provides an overview of clearVISN, an
explanation of each application and
descriptions of all concepts necessary to
understand and use the application
efficiently.

clearVISN Configuration
and Use

Provides information for starting each
application, configuring them and
general use information.

xiii

Correspondence
Documentation Comments
If you have comments or suggestions about this document, send them to the Network
Products Engineering.
Attn.:
FAX:
E-MAIL:

Documentation Project Manager
(508) 486-6093
doc_feedback@lkg.mts.dec.com

Online Services
To locate product specific information, refer to the following online services:
BBS

To read the Bulletin Board System, set your modem to 8 bits, no parity, 1 stop bit and
dial 508-486-5777 (U.S.)

WWW

The Digital Equipment Corporation Network Products Business Home Page on the
World Wide Web is located at the following addresses:

xiv

North America:

http://www.networks.digital.com

Europe:

http://www.networks.europe.digital.com

Australia:

http://www.digital.com.au/networks

How to Order Additional Documentation
To order additional documentation, use the following information:
To Order:

Contact:

By Telephone

USA (except Alaska, New Hampshire, and Hawaii):
1-800-DIGITAL (1-800-344-4825)
Alaska, New Hampshire, and Hawaii: 1-603-884-6660
Canada: 1-800-267-6215

Electronically
(USA only)

Dial 1-800-DEC-DEMO
(For assistance, call 1-800-DIGITAL)

By Mail
(USA and
Puerto Rico)

DIGITAL EQUIPMENT CORPORATION
P.O. Box CS2008
Nashua, New Hampshire 03061
(Place prepaid orders from Puerto Rico with the local Digital
subsidiary: 809-754-7575)

By Mail
(Canada)

DIGITAL EQUIPMENT of CANADA LTD.
940 Belfast Road
Ottawa, Ontario, Canada K1G 4C2
Attn.: A&SG Business Manager

Internationally

DIGITAL EQUIPMENT CORPORATION
Attn.: A&SG Business Manager
c/o local Digital subsidiary or approved distributor

Internally

U.S. Software Supply Business (SSB)
DIGITAL EQUIPMENT CORPORATION
8 Cotton Road
Nashua, New Hampshire 03063

xvi

Safety

Overview
Any warning or caution that appears in this manual is defined as follows:.
WARNING

Contains information to prevent personal injury.

CAUTION

Contains information to prevent damage to
equipment.

VORSICHT

Enthält Informationen, die beachtet werden müssen
um den Benutzer vor Schaden zu bewahren.

ACHTUNG

Enthält Informationen, die beachtet werden müssen
um die Gerate vor Schaden zu bewahren.

DANGER

Signale les informations destinées à prévenir les
accidents corporels.

ATTENTION

Signale les informations destinées à prévenir la
détérioration du matériel.

AVISO

Contiene información para evitar daños personales.

PRECAUCIÓN

Contiene información para evitar daños al equipo.

xvii

The cautions that must be observed for the hardware described in this manual are listed
below in English, German, French, and Spanish.

xviii

CAUTION

This action deletes all configured settings and
replaces them with factory default values. All
configuration settings will be lost.

ACHTUNG

Bei diesem Vorgang werden alle
Konfigurationseinstellungen gelöscht und die
Werkseinstellungen wieder eingesetzt. Alle
Konfigurationsdaten gehen verloren.

ATTENTION

Cette action supprime tous les paramètres de
configuration et les remplace par des valeurs
prédéfinies. Tous les paramètres de configuration
seront perdus.

PRECAUCIÓN

Esta intervención borrará todos los parámetros de
configuración y los sustituirá por valores por defecto
definidos de fábrica. Se perderán todos los
parámetros de configuración.

Chapter 1
Product Introduction

Overview
Introduction
This chapter describes the DECserver 900MC module and its features.

In This Chapter
Topic

Page

What is the DECserver 900MC?

1-2

Features

1-3

Product Introduction 1-1

What is the DECserver 900MC?

What is the DECserver 900MC?
The DECserver 900MC is a nine-port network access server that provides remote
access connections to an Ethernet local area network (LAN). The DECserver 900MC
includes four megabytes (MB) of memory and runs Version 2.1 (or greater) of the
DECserver Network Access Server (DNAS) software.
You can install and configure the DECserver 900MC in a DEChub 900 MultiSwitch
(also referred to as DEChub 900) or as a stand-alone unit in a DEChub ONE or
DEChub ONE-MX docking station.
The DECserver 900MC contains one serial port and eight modem ports. Each modem
port is equipped with a built-in Microcom DeskPorte Fast+ modem.
Each DeskPorte Fast+ modem provides the following features:
•

V.34 data rates up to 33,600 Bps

•

2-wire switched line interface through individual 8-pin MJ connectors

•

Universal Direct Access Arrangement (DAA)
(DAA allows different countries to connect without requiring different product
variants or hardware jumpers.)

•

V.42 and V.42bis error correction and data compression protocols

•

Microcom Networking Protocol (MNP) support (see Appendix D, Microcom
Networking Protocol)

•

Cellular operation using the MNP Class 10 protocol with Adverse Channel
Enhancements (ACE) (see Appendix D, Microcom Networking Protocol)

1-2 Product Introduction

Features

Features
Your DECserver 900MC includes the following features.

Hot Swap
The module’s hot swap capability allows you to install or remove the module from a
DEChub 900 without turning off power to the hub.

Configuration and Management
The module offers the following configuration and management options:
•

Set-up port for initial configuration of the module using a terminal or personal
computer.

•

Advanced Graphical User Interface (GUI) manageability with Digital's Access
Server Manager application.

•

Advanced Graphical User Interface (GUI) manageability with Digital's
clearVISN MultiChassis Manager application.

Protocols and Standards
The module supports the following protocols and standards:
•

Compatibility with the proposed ITU-T V.34 protocol (14400 to 33600 bps)
modem port speeds. (V.34 is implemented using Rockwell International
Corporation’s V.FC chip.)

•

Serial port speeds of up to 115200 bps

•

2-wire switched line operation

•

ITU-T protocol standards: V.21, V.22, V.22bis, V.23, V.32, and V.32bis

•

Bell 212A and Bell 103 protocol standards

•

V.42 error correction, including LAPM and MNP Classes 2 to 4 (see Appendix D,
Microcom Networking Protocol)

•

V.42bis compression as well as MNP Class 5 Data Compression (see Appendix
D, Microcom Networking Protocol)

•

MNP Class 10 Adverse Channel Enhancements (see Appendix D, Microcom
Networking Protocol)

Product Introduction 1-3

Features

Special Features
The module’s built-in modems include the following special features:
•

Enhanced operation in cellular environments

•

Multi-protocol auto-answering to automatically answer incoming calls using
various modulation protocols

•

Trellis coded modulation for forward error correction

•

Near and far end echo cancellation

•

Preset factory configuration switches for V.34 auto-reliable operation

•

Auto-dial, auto-answer, manual dial, and manual answer capabilities during
asynchronous operation

•

Automatic power-up diagnostics

•

Asynchronous 11-bit character support

1-4 Product Introduction

Chapter 2
Installing the Module

Overview
Introduction
This chapter explains how to install the DECserver 900MC in a DEChub 900
Multiswitch. To install the module as a standalone unit, refer to the DEChub One (or
DEChub ONE-MX) Installation manual.

In This Chapter
Topic

Page

Module Components

2-2

How to Install the Module

2-8

Installing the Module 2-1

Module Components

Module Components
This section describes the front and back panels of the DECserver 900MC module and
the components of each panel. For problem-solving information using the LEDs, refer
to Appendix A, Problem Solving.

2-2 Installing the Module

Module Components

Front Panel Features
Table 2-1 describes the front-panel components that are illustrated in Figure 2-1.
Table 2-1: Front Panel Components
Item

Icon

Name

Description

Power LED

Lights when the module has
power.

Module OK
LED

Lights when the module passes
self-test. Flashes when a non-fatal
error occurs on self-test. If the
module fails self-test, the Module
OK LED is off.

Network OK

Lights when the module has an
active network connection.

Network
Activity LED

Flashes or remains on depending
on network activity.

SevenSegment
Display

Provides error and status
information regarding testing,
loading, and power conditions
(see Appendix A, Problem
Solving for details).

Flash RAM
Slot

Provides an opening for the Flash
RAM card.

Reset Switch

Resets the module to factory
defaults. To reset: while turning
on the power, press and hold the
reset switch until the Module OK
LED flashes; or if the DECserver
900MC is in operation mode (the
seven-segment display shows the
"race track" pattern), hold the
switch in for ten-seconds. The
module reboots with factory
defaults.

Port State
LEDs

Provides connection status on a
per port basis.

Installing the Module 2-3

Module Components
Table 2-1: Front Panel Components
Item

Name

Description

Serial Port
Connector

Provides connection for an
asynchronous device. The serial
port connector is known as the
console port and referred to as
Port 9 by the software.

Modem Port
Connectors
(8-pin MJ)

Connects the built-in modem to a
two-wire telephone line. Supports
both MP8 and MP6 phone cables.

2-4 Installing the Module

Icon

Module Components
Figure 2-1: Front Panel LEDs and Connector

2
Ethernet

5
DECserver 900MC

1
2
3
4

5
6
7
8

NPB-0692-96F

Installing the Module 2-5

Module Components

Back Panel Features
Table 2-2 describes the back panel components that are illustrated in Figure 2-2.
Table 2-2: Back Panel Components
Item

Name

Description

Locking tab

Locks the module into a DEChub 900
backplane or into a DEChub ONE docking
station.

48-pin connector

Provides network and power connections
to the module when the module is installed
into a DEChub 900 or DEChub ONE
docking station.

Grounding bolt

Provides a chassis grounding connection
to the module when the module is installed
into a DEChub 900 MultiSwitch or a
DEChub ONE docking station.

Manufacturing label

Lists the module’s part number, serial
number, revision level, and power
requirements.

160-pin connector

Provides network and power connections
to the module when the module is installed
into a DEChub 900 or a DEChub ONE
docking station.

Mounting tab

Secures the module to the backplane when
the module is installed into a DEChub 900
or a DEChub ONE docking station.

Grounding fingers

Provide additional chassis grounding
between the module and a DEChub 900 or
a DEChub ONE docking station.

2-6 Installing the Module

Module Components
Figure 2-2: Back Panel Features

Installing the Module 2-7

How to Install the Module

How to Install the Module
The hot-swap feature allows you to install the module into the DEChub 900 without
turning off power to the hub. Seating the module initiates the module’s powerup
sequence if enough power is available.
To install the module, complete the following tasks:

Task 1: Compare the Power Ratings
Compare the module’s power ratings with the values shown in the Hub Manager Status
display (Figure 2-3).
If any of the module's power requirements (1) exceed the values shown in the status
display (2) add another power supply (see the DEChub 900 MultiSwitch Owner’s
Manual).
Figure 2-3: Power Ratings

2
25.6 W
4.1 A

5 V 20.5 W

0.1 A

12 V 1.2 W

Available: 90.5 W
5V: 13.0 A, 15V: 3.5 A

260 MA 15 V 3.9 W

NPB-0715-96F

2-8 Installing the Module

How to Install the Module

Task 2: Seat the Module
To seat the module into the DEChub 900 MultiSwitch, complete the following steps:
Step

Action

Place the module’s mounting tab (1) into a mounting slot on the
DEChub 900 MultiSwitch.

Pull up on the release lever (2) to its unlocked position.

Pivot the module on the mounting tab and align the connectors.

Firmly push the module onto the backplane connectors.

Press down on the release lever (3) to ensure that it is locked.

Figure 2-4: Seating the Module

Installing the Module 2-9

How to Install the Module

Task 3: Verify Initial LED Operation
If this is a new installation, turn on the power to the DEChub 900 MultiSwitch. If the
module was installed while the DEChub 900 was powered up, seating the module will
initiate the module’s power up sequence. For locations of the module’s LEDs, refer to
Figure 2-1.
Verify that the module’s Power LED and the Module OK LED light within 1 minute.
The LEDs light in the following stages:
Stage

Description

The Power LED lights when power is applied to the DEChub 900, then
the module performs a self-test.

After the module completes self-test, the Module OK LED lights.
Then the Hub Manager status identifies the module as a DECserver
900MC.

NOTE
If the LEDs do not operate as described, refer to Appendix A, Problem Solving.

2-10 Installing the Module

How to Install the Module

Task 4: Connect Port Cables
Connect the port cables to any available port connector on the module. Ports 1 through
8 contain built-in modems. The console port is a serial port, also known as Port 9 by
the software. For more information on the proper cables to use, see Appendix B,
Connector and Cable Assignments.
To connect the port cables to the module, complete the following steps:
Step

Action

Align the release tab on the cable plug (1) with the keyway on the
module’s connector.

Insert the plug into the connector, ensuring that the release tab snaps into
the locked position.

Figure 2-5: Connecting the Cable

1
2

5
DECserver 900MC

NPB-0694-96F

NOTE
The DECserver 900MC does not support the out-of-band management (OBM)
port or the setup port on the DEChub One. However, console redirect is supported.

Installing the Module 2-11

Chapter 3
Installing the Setup Port Cable

Overview
Introduction
This chapter describes how to connect the DECserver 900MC module to the setup port
on a DEChub 900 MultiSwitch.

In This Chapter
Topic

Page

Signaling Standards

3-2

Setup Port Device Cabling

3-3

Connecting the Setup Port

3-4

Installing the Setup Port Cable 3-1

Signaling Standards

Signaling Standards
Signals from the DEChub 900 Hub setup port conform to the EIA-232D signaling
standard at 9600 baud. To the user, the port appears as a data terminal equipment
(DTE) device.
The DEChub 900 Hub Manager setup port is compatible with devices that use the EIA423 signaling standard.

3-2 Installing the Setup Port Cable

Setup Port Device Cabling

Setup Port Device Cabling
The setup port (Figure 3-1) on the DEChub 900 MultiSwitch can be connected to a
setup port device (a terminal or personal computer). Use the following cables and
adapters to connect the setup port to a setup port device:
If the setup port
device is...

Use this cable...

With this adapter...

PC with a 9-pin D-Sub
communications port

BN24H-xx1

H8571-J

Terminal with a 25-pin DSub connector

BN24H-xx

H8575-A

Terminal with a 6-pin
MMJ connector

BN24H-xx

Not required.

1.xx indicates cable length in meters.

Installing the Setup Port Cable 3-3

Connecting the Setup Port

Connecting the Setup Port
To connect a personal computer or a terminal (3) to the setup port (2) on the DEChub
900 MultiSwitch , complete the following steps:
Step

Action

Ensure that the transmit and receive baud rates on the setup port device
(3) are set to 9600 baud.

Connect the setup port device to the setup port connector.

3-4 Installing the Setup Port Cable

Connecting the Setup Port
Figure 3-1: Setup Port Cabling Components

1
2

DEChub 900 Multiswitch
2
3

H8571-J
BN24H

H8575-A
NPB-0714-96F

The following legend identifies the setup port cabling:
Item

Description

OBM Port

Setup Port

Setup Port Device

Installing the Setup Port Cable 3-5

Chapter 4
Configuring the Module in a DEChub 900

Overview
Introduction
This chapter describes how to configure your DECserver 900MC when it resides in a
DEChub 900 MultiSwitch.

In this Chapter
Topic

Page

DEChub 900 MultiSwitch INSTALLATION MENU

4-2

[5] Start Redirect Mode

4-3

Using Menus to Configure the Module

4-4

[1] Reset with Factory Defaults

4-5

[2] Reset with Current Settings

4-6

[3] Show Current Settings

4-7

[4] Configure IP

4-8

Configuring the Module in a DEChub 900 4-1

DEChub 900 MultiSwitch INSTALLATION MENU

DEChub 900 MultiSwitch INSTALLATION MENU
The following example shows the DEChub 900 MultiSwitch INSTALLATION
MENU.
To access the module’s installation menu, you must choose the following option:
[5] Start Redirect Mode.
The following example shows the dialog associated with this option:

DEChub 900 MultiSwitch
=========================================================
DEChub 900 MultiSwitch INSTALLATION MENU
[1]
[2]
[3]
[4]
[5]

Reset with Factory Defaults
Reset with Current Settings
Show Current Settings
Configure IP
Start Redirect Mode

================================================================
Enter selection number: 5 <Return>
Press Return for Main Menu ...

4-2 Configuring the Module in a DEChub 900

[5] Start Redirect Mode

[5] Start Redirect Mode
The Start Redirect Mode option redirects the DEChub 900 MultiSwitch Hub
Manager set-up port to the set-up port of any network module (such as the DECserver
900MC) that is installed into the DEChub 900. This option allows you to configure or
obtain status of an installed network module by accessing the specified network
module’s installation menu.
After you choose the Start Redirect Mode option from the DEChub 900
MultiSwitch INSTALLATION MENU, the screen prompts you for a slot number
as shown in the following example. After you enter the number of the slot in which the
DECserver 900MC is installed (3, in this example), the console is redirected to this
slot.

NOTE
The slot number will change to reflect the slot in which your module is installed.

The following example shows you how to select a slot number:

Enter selection: 5
=====================================================
Enter the slot number for redirection (1-8): 3 <Return>
Console redirected to 3: DECserver 900MC
Attempting connection [Ctrl/C to Abort]...
Connection successful!

If the redirection is successful, after you press <Return>, the DECserver 900MC
INSTALLATION MENU appears on your screen.

Configuring the Module in a DEChub 900 4-3

Using Menus to Configure the Module

Using Menus to Configure the Module
The following screen shows the options available from the DECserver 900MC
INSTALLATION MENU when the module is operating in a DEChub 900
configuration.

NOTE
When your module is installed in the DEChub 900, the slot number where the
module is installed appears at the top of the menu.

DECserver 900MC

- slot 3

===========================================================
DECserver 900MC INSTALLATION MENU
[1]
[2]
[3]
[4]

Reset with Factory Defaults
Reset with Current Settings
Show Current Settings
Configure IP

===========================================================
Enter selection: [n] <Return>

4-4 Configuring the Module in a DEChub 900

[1] Reset with Factory Defaults

[1] Reset with Factory Defaults
This option reboots the module, causing its configured Non-volatile Random Access
Memory (NVRAM) parameters to be initialized to factory default values followed by
a module reset. If you need to reboot the module and retain the current settings, choose
option [2] from the DECserver 900MC INSTALLATION MENU.

CAUTION
This action deletes all configured settings and replaces them with factory default
values. All configuration settings will be lost.

NOTE
Allow approximately 3 to 5 minutes for the module to reboot and complete
self-test.

The following example shows the dialog associated with this option:

Enter selection : 1
DECserver 900MC - slot 3
==========================================================
RESET WITH FACTORY DEFAULTS
* * * * * * * * * * * * * * * * * * * * * * * * * *
*
IMPORTANT!
IMPORTANT!
IMPORTANT!
*
* * * * * * * * * * * * * * * * * * * * * * * * * *
This selection will delete the current configuration
settings and reset the system with the factory default
settings. All configuration settings will be lost.
* * * * * * * * * * * * * * * * * * * * * * * * * *
==========================================================
Press Y to confirm [N]: Y <Return>
Press Return for Main Menu...

Configuring the Module in a DEChub 900 4-5

[2] Reset with Current Settings

[2] Reset with Current Settings
This option resets the module but leaves the module’s configured nonvolatile
configuration storage parameters at their current values.

NOTE
Allow approximately 1 minute for the module to restart.

The following example shows the dialog associated with this option:

Enter selection:

DECserver 900MC - slot 3
=============================================================
RESET WITH CURRENT SETTINGS
This selection will reset your system with the current
configuration settings.
=============================================================
Press Y to confirm [N] : <Return>
Press Return for Main Menu...

4-6 Configuring the Module in a DEChub 900

[3] Show Current Settings

[3] Show Current Settings
This option shows the module’s current settings. If the module is being configured for
the first time, some fields are blank.
The following example shows the display associated with this option.

Enter selection : 3
DECserver 900MC - slot 3
=================================================================
DECserver 900MC,Network Access SW V2.1,HW=V1.4,RO=V6.4-0,SW=BL11,
LAT V5.1, LOAD IMAGE: WWENG2
SysUpTime
: 00:49:59 0 resets
SNMP Read/Write Community
: PRVTRW
Interface
Ethernet

IP Address
16.20.52.101

Subnet Mask
255.255.255.0

Def.Gateway

Other Info
08-00-2b-a2-a4-34

==================================================================
Press Return Key to Continue .....
DECserver 900MC - slot 3
==================================================================

Configuring the Module in a DEChub 900 4-7

[4] Configure IP

[4] Configure IP
This option provides you with IP configuration selections.
The following example shows the dialog associated with this option:

Enter selection : 4
DECserver 900MC - slot 3
=========================================================
IP CONFIGURATION
[1]
[2]
[3]

Set SNMP Read/Write Community
Set In-Band Interface IP Address
Return to Main Menu

=========================================================
Enter selection number : [n] <Return>

The following pages describe the IP Configuration options:
Topic

Page

[1] Set SNMP Read/Write Community

4-9

[2] Set In-Band Interface IP Address

4-10

4-8 Configuring the Module in a DEChub 900

[4] Configure IP

[1] Set SNMP Read/Write Community
This option prompts you to enter the module’s read/write community name. The
community name can be used for read/write access control.
The following example shows the dialog associated with this option:

Enter selection : 1

DECserver 900MC - slot 3
================================================================
SET SMNP READ/WRITE COMMUNITY
Format:

The format for a community name is a string, consisting
of 4 to 31 printable ASCII characters, that
describes the relationship between an SNMP agent and
one or more SNMP managers. The string defines the
authentication mechanism that is employed to validate
the use of the community by the sending SNMP entity.
================================================================
Enter the community string [public] : public96 <Return>
SNMP Read/Write community string set.
Press Return for IP Configuration Menu...

Configuring the Module in a DEChub 900 4-9

[4] Configure IP

[2] Set In-Band Interface IP Address
This option prompts you to change or enter the module’s in-band IP address, subnet
mask, and default gateway for the in-band interface. If an IP address was previously
configured, the screen displays an in-band IP address.

NOTE
If you would like to change a previously configured IP address on the module, you
must first change the IP address and then, reboot the module in order for the new
IP address to take effect.

You do not need to configure the module with a subnet mask for SNMP
communications with management stations located on the same subnet as the module.
The factory default setting is no in-band address.
The following example shows the dialog associated with this option:

Enter selection : 2
DECserver 900MC - slot 3
=================================================================
IN-BAND INTERFACE IP ADDRESS CONFIGURATION
Format: The standard 4 octet dotted decimal notation in which
each octet of the address is represented as a decimal
.
separated by a ’.’ character.
example: 16.20.40.156
To delete the IP address, enter 0 in the appropriate
address field.
Interface

IP Address

Subnet Mask

Def.Gateway

Other Info

In-Band
OBM Port

Active

==================================================================
Enter the IP address [] : 16.20.216.91 <Return>
Enter the Subnet Mask [] : 255.255.255 0 : <Return>
Enter the Default Gateway [] 16.21.0.1
<Return>
Press Return for IP Configuration Menu.....

4-10 Configuring the Module in a DEChub 900

Chapter 5
Installing Flash RAM

Overview
Introduction
This chapter describes how to use a Flash RAM card for loading or upgrading the
operational software. The Flash RAM card can be hot swapped and may be inserted
and removed at anytime.

In This Chapter
Topic

Page

Inserting the Flash RAM Card

5-2

Booting the Module

5-3

Installing Flash RAM 5-1

Inserting the Flash RAM Card

Inserting the Flash RAM Card
The Flash RAM card when properly inserted will protrude from the front panel about
1/4 inch. The Flash RAM card is keyed and cannot be inserted improperly.
To insert the Flash RAM card, complete the following steps:
Step

Action

Locate the Flash RAM slot on the front of the module (Figure 5-1).

Insert the Flash RAM card into the Flash RAM slot.

Figure 5-1: Inserting the Flash RAM Card

DECserver 900MC

DECserver 900TM

1
2
3
4

5
6
7
8

NPB-0695-96F

5-2 Installing Flash RAM

Booting the Module

Booting the Module
Once the Flash RAM card is in place, load the operational software by powering the
module. Once you boot the DECserver 900MC, the Flash RAM card may be left in
place or removed.

NOTE
You can update Flash RAM by issuing the INITIALIZE FROM ETHERNET
IMAGE xxx UPDATE FLASHRAM command from the DECserver 900MC. For
more information, see the Network Access Server Command Reference.

Installing Flash RAM 5-3

Chapter 6
Configuring the Modem Ports Using the
Access Server Manager

Overview
Introduction
In order to use the DeskPorte Fast+ built-in modems on the DECserver 900MC, you
must first configure them. DIGITAL recommends that you use the Access Server
Manager application to configure the DECserver 900MC modems. You can also use
the Access Server Manager to change modem properties, update the modem firmware,
and send commands manually to the modem.
You can perform many of these Access Server Manager functions using the
DECserver Network Access Software console commands (see Chapter 7, Configuring
the Modems Ports Using the Console Commands).

NOTES
•

For software installation information, refer to the DECserver Network Access
Software Installation manuals.

•

The appearance and layout of the Access Server Manager screens may change in
future versions of the Access Server Manager software.

In This Chapter
Topic

Page

Adding the DECserver 900MC to the Database

6-2

Configuring the Modem

6-3

Configuring the Modem Ports Using the Access Server Manager 6-1

Adding the DECserver 900MC to the Database

Adding the DECserver 900MC to the Database
To configure the DECserver 900MC modems using the Access Server Manager
application, you have to:
1) Add the DECserver 900MC to the Access Server Manager’s database.
2) Set the modem country location.
Start the Access Server Manager application and complete the following steps:
Step

Action

With the Access Server Manager Browser displayed, click on New.

Enter the DECserver 900MC’s Internet address or select it from the
drop-down list if you entered the address into the NetRider BootP
Loader database.

Enter a name for the DECserver 900MC access server.

Click on OK. The application displays the Country page.

Is the displayed country correct?
•

If yes, click on Close.

•

If no, select the correct country from the drop-down list and click on
the Set Country Now. Then, click on Close.

Note: If you change the country code, reboot the DECserver 900MC
to have the new country code take effect.
Before Phone Line Connection: Be sure to set the correct country
location for the modems before you connect them to telephone lines.

6-2 Configuring the Modem Ports Using the Access Server Manager

Configuring the Modem

Configuring the Modem
After starting the Access Server Manager application and opening the Modem dialog,
you can:
•

Use the Configure page to set modem properties for each modem.

•

Use the Command page to manually send commands to one or more modems.

•

Use the Firmware page to upgrade the modem firmware.

•

Use the Country page to set the country location for the modem.

Setting Modem Properties
To set modem properties, start the Access Server Manager application and complete
the following steps:
Step

Action

Select the access server from the Access Server Manager Browser and
click on Open.

From the Configuration page:
a) Click on Modems
b) Click on Configure

Configuring the Modem Ports Using the Access Server Manager 6-3

Configuring the Modem
Step

Action

From the Configuration page in the Modem dialog, select the port whose
modem you want to configure or click on Select All to configure all of
the modem ports.

Click on Properties.

6-4 Configuring the Modem Ports Using the Access Server Manager

Configuring the Modem
Step

Action

On the General page, set any or all of the following values:
•

Phone Uses — tone or pulse dialing.

•

Serial Port — enter port speed or click on use port settings to set
modem speed to be the same as the port speed settings.

•

Flow Control — check use flow control and select hardware or
software flow control.

Click on Help to read information about each field. Click on OK when
you have finished or click on the Commands tab.

Configuring the Modem Ports Using the Access Server Manager 6-5

Configuring the Modem
Step

Action

On the Commands page, set the following modem commands, if
required. In most cases, you can accept the default settings.
•

Factory Init — Resets the modem to factory default settings.

•

DSR follows connect — Sets the DSR (Data Set Ready) state when
a connection is established.

•

Auto Answer enabled — Tells the modem to answer incoming calls.

•

Result Codes — Causes the modem to display verbose (rather than
numeric) result codes.

•

No DTR disconnects — Requires a DTR (Data Terminal Ready)
signal to be present in order for the modem to accept commands and
causes the modem to hang up if the DTR is not present.

•

Save configuration — Tells the modem to save the modem settings
to a user profile (commonly referred to in modem documentation as
NVRAM locations) and to use that user profile for initialization
when powering up or resetting the modem.

•

Port Speed — If your modem requires a command to lock the serial
port speed, check this box.

•

Lock Speed — If the Port Speed command required box is
checked, enter the command your modem uses to lock port speed.

•

Extra settings — Commands for any additional modem settings that
are necessary. No additional commands are required for most
modems used with access servers.

Click on OK when you have finished or click on the Configure tab.

6-6 Configuring the Modem Ports Using the Access Server Manager

Configuring the Modem

Sending Commands to the Modem
To manually send commands to the modem on one or more ports, start the Access
Server Manager application and complete the following steps:
Step

Action

Select the access server from the Access Server Manager Browser and
click on Open.

From the Configuration page:
a) Click on Modems
b) Click on Configure

Click on the Command tab in the Modem dialog.

From the drop-down list, select the port to which you want to send
modem commands or click on Select All to send commands to all
modems

In the Command data field, enter the modem command you want to
send (see Appendix F, AT Commands).

Configuring the Modem Ports Using the Access Server Manager 6-7

Configuring the Modem
Step

Action

Click on Send. (The command you send and the modem’s response
appear in the Status box.)
Clearing the Status Box: Click on Clear to delete any messages that
appear in the Status box.

Click on Close when finished.

Upgrading Modem Firmware
Start the Access Server Manger application and do the following:
Step

Action

Insert the Modem firmware diskette into a diskette drive or copy the
firmware file to your PC’s hardware drive.

Select the access server from the Access Server Manager Browser and
click on Open.

From the Configuration page:
a) Click on Modems
b) Click on Configure

Click on the Firmware tab in the Modem dialog box.

6-8 Configuring the Modem Ports Using the Access Server Manager

Configuring the Modem
Step

Action

From the drop-down list, select the port whose firmware you want to
upgrade or click on Select All to send upgrade firmware on all ports

Click on Upgrade Firmware and select the firmware file that you want
to use.

Click on Open.

Click on Close.

NOTE
It takes approximately 6 minutes for an individual modem to complete a firmware
upgrade. This means it may take 48-60 minutes to upgrade all eight ports.

Configuring the Modem Ports Using the Access Server Manager 6-9

Configuring the Modem

Changing the Country Location
Set the country location before connecting the modem to a telephone line. The country
setting indicates the country where the DECserver 900MC module is used.

NOTE
The DECserver 900MC must be rebooted in order for the country code to take
effect.

To change the country code, start the Access Server Manager application and complete
the following steps:
Step

Action

Select the access server from the Access Server Manager Browser and
click on Open.

From the Configuration page:
a) Click on Modems
b) Click on Configure

Click on the Country tab on the Modem dialog.

6-10 Configuring the Modem Ports Using the Access Server Manager

Configuring the Modem
Step

Action

From the drop-down list, select the country where you are using the
DECserver 900MC access server

Click on Set Country Now.

Click on Close.
Note: The DECserver 900MC must be rebooted in order for the
country code to take effect.

Configuring the Modem Ports Using the Access Server Manager 6-11

Chapter 7
Configuring the Modems Ports Using the
Console Commands

Overview
Introduction
In order to use the DeskPorte Fast+ built-in modems on the DECserver 900MC, you
must first configure them. DIGITAL recommends that you use the Access Server
Manager application to configure the DECserver 900MC modems (see Chapter 6,
Configuring the Modem Ports Using the Access Server Manager). However, you can
perform some functions using the DECserver Network Access Software console
commands.
This chapter explains how to use the console commands. For more information on the
console commands, see the Network Access Server Management and Network Access
Server Command Reference manuals.

In This Chapter
Topic

Page

Setting the Country Code

7-2

Logging Out Ports

7-4

Communicating With the Modem

7-5

Configuring the Modems Ports Using the Console Commands 7-1

Setting the Country Code

Setting the Country Code
Introduction
You can connect a terminal to the console port, known as port 9 by the DECserver
Network Access Software (DNAS). Once the terminal is connected, use DNAS
commands to set the modem country code and to log out the port. If necessary, you can
use the console port to send AT commands (see Appendix F, AT Commands) directly
to the modem.

Displaying the Current Country Setting
Issue the SHOW/LIST/MONITOR COUNTRY command at the console port to
display all of the valid country codes and the current country location setting.

Setting the Country Code
Before connecting the modem to a telephone line, set the country code for the country
in which the DECserver 900MC is used.

NOTE
In order for the new country code to take effect, you must reboot the DECserver
900MC.

To set the country code, issue the following command at the console port:
DEFINE COUNTRY country_number

Valid country codes are listed in Table 7-1.
Example
This example shows how to set the country standard for South Africa and reboot the
DECserver 900MC using a 10-minute delay:
Local> DEFINE COUNTRY 16
Local> INITIALIZE DELAY 10
For more information about the INITIALIZE command, refer to the DECserver
Network Access Server Command Reference manual.

7-2 Configuring the Modems Ports Using the Console Commands

Setting the Country Code

Table 7-1: Country Codes
Country

Code

Country

Code

Australia

Japan

Austria

Netherlands

Belgium

New Zealand

Czech Republic

Norway

Denmark

Poland

Finland

South Africa

France

Spain

Germany

Sweden

Ireland

Switzerland

Israel

United Kingdom

Italy

United States

Italy SIP

Configuring the Modems Ports Using the Console Commands 7-3

Logging Out Ports

Logging Out Ports
Introduction
You can log out a port and reset the port characteristics to their factory defaults or you
can log out a port and send a reset signal to the port.

Logging Out a Port and Resetting Port Characteristics to Factory Defaults
To log out a port and reset the port’s characteristics to the factory defaults, use the
following command:
LOGOUT PORT port-list FACTORY
Example
This example shows how to log out ports 2 through 8 and reset the port characteristics
to their factory defaults.
Local> LOGOUT PORT 2-8 FACTORY

Logging Out a Port and Sending a Reset Signal
To log out a modem port, use the following command:
LOGOUT PORT port-list MODEM [RESET]

NOTE
This command performs the functional equivalent of a power-cycle.

Example
This example shows how to disconnect sessions on ports 2 through 8 and send a reset
signal to these ports.
Local> LOGOUT PORT 2-8 MODEM

7-4 Configuring the Modems Ports Using the Console Commands

Communicating With the Modem

Communicating With the Modem
DIGITAL recommends that you use the Access Server Manager application to
configure the modem or send commands directly to the modem. If necessary, you can
communicate with the modem using a local or remote console.
To communicate directly with the modem using the console port, complete the
following steps. For more information about DNAS command syntax, see the Network
Access Server Command Reference manual.
Step

Action

Set up a service on the target modem port using the SET SERVICE
CONNECTIONS ENABLED command.

Connect to the service using the CONNECT command.

Enter the correct modem commands. See Appendix F, AT Commands
for more information about AT commands.

Example
This example shows how to establish a service on modem port 1 called modems,
connect to the service, and enter a modem command. The modem responds with OK,
indicating it is ready to receive additional commands.
Local> SET SERVICE modems PORTS 1 CONNECTIONS ENABLED
Local> CONNECT modems
Local> AT
OK
When you are done communicating with the modem, press the Break key to return to
the Local> prompt. Then, type Disconnect at the Local> prompt.

Configuring the Modems Ports Using the Console Commands 7-5

Chapter 8
Removing the Module

Overview
Introduction
This chapter describes how to remove the module from a DEChub 900 MultiSwitch.
To remove the module from a standalone unit, refer to the DEChub ONE (or DEChub
ONE-MX) Installation manual.

In This Chapter
Topic

Page

Removing the Cable

8-2

Unseating the Module

8-3

Removing the Module 8-1

Removing the Cable

Removing the Cable
To remove cables from the module, press the release tab (1) on the cable plug, then pull
out the cable (see Figure 8-1).
Figure 8-1: Removing the Cable

1
2

5
DECserver 900MC

NPB-0771-96F

8-2 Removing the Module

Unseating the Module

Unseating the Module
To unseat the module from the DEChub 900, complete the following steps:
Step

Action

Hold the module and lift the release lever (1) located at the top of the
DEChub 900 slot.

While holding up the release lever (2), pivot the module back on its
bottom mounting tab (3).

Remove the module.

Figure 8-2: Unseating the Module

1
2

NPG-0008-95F

Removing the Module 8-3

Appendix A
Problem Solving

Overview
Introduction
This appendix describes the LED functions and provides problem solving information.
The sections of this appendix are listed below.

In This Appendix
Topic

Page

LED Descriptions

A-2

Normal Powerup

A-4

Problem Solving Using the LEDs

A-5

Problem Solving Using the Seven-Segment Display

A-9

Troubleshooting Tips When Using Your Built-in Modems

A-11

Problem Solving A-1

LED Descriptions

LED Descriptions
The module and port LEDs provide dynamic indications of the status of the module
and ports. The LEDs can be in various states and can change color depending on the
operational status of the module or port and the level of activity on the network.

Module LED States
The module’s LEDs can be in various states (off, on, or flashing) and can change color
depending on the operational status of the module or the level of activity on the
network.
Table A-1 shows the states that are possible for each of the module’s LEDs.
Table A-1: Module LED States
LED
Name

Off

Flashing

Power

No power to
module.

Module
receiving
power.

Faulty power
connection or
insufficient
power.

Module
OK

After 2
minutes, the
module failed
self-test.

Module
passed selftest.

Non-fatal selftest failure.
Unit may still
be operational.

Network
OK

Module is not
connected to a
properly
terminated and
enabled LAN
through the
DEChub 900.

Network
connection
is
operational.

Network
connection is
disabled by
network
management.

Network
Activity

No network
activity.

Network has
heavy traffic.

Flashes more
rapidly and
appears
brighter as
network traffic
increases.

A-2 Problem Solving

ICONS

LED Descriptions

Port LED States
The module also contains an LED on each port. The port LED’s can be in various states
(off, orange, or green).
Table A-2 shows the possible states for the port LEDs.
Table A-2: Port State LEDs
LED Name

Off

Orange

Green

Port State

Module is online,
but the built-in
modem on the
port is not in use.

Port is
receiving
power. Port
LED will go off
when the
module is
booted. If
diagnostics
detects a fatal
error with the
modem, the
port LED will
remain orange.

The built-in
modem on the
port is
connected and
operating,
either
answering or
originating a
call.

Note: The term
online refers to
the module
operating with the
DECserver
Network Access
Software code.

Problem Solving A-3

Normal Powerup

Normal Powerup
When the module’s power is initially turned on, the following events occur:
Event

Description

The Power LED lights and remains lit. The Port LEDs turn
orange. All other LEDs light and then turn off. This verifies
that the individual LEDs are operational.

The module initiates its built-in self-test. The seven-segment
display indicates the self-test status.

After the successful completion of self-test (approximately
two to five minutes), the Module OK LED lights and
remains on.

The remaining LEDs indicate their operational status, as
described in Table A-3.

A-4 Problem Solving

Problem Solving Using the LEDs

Problem Solving Using the LEDs
When diagnosing a problem with the module, note that the problem is often indicated
by the states of the module LEDs. Table A-3 lists the states of the LEDs for various
error conditions that can occur during initial installation of the device, along with
probable causes and corrective actions to take.
Table A-3: Problem Solving Using the LEDs
Symptom

Probable Cause

Corrective Action

Power LED is off.

Bad power LED.

Replace the module.

The module is not
receiving power.

Check the power LED
on the DEChub 900.

If the DEChub 900
power LED is off, the
cause of the problem
is the DEChub 900
power supply.

See the troubleshooting
procedures in the
DEChub 900
MultiSwitch Owner’s
Manual.

If the DEChub power
LED is on and the
other power LEDs are
off, then the DEChub
has a power problem.

See the troubleshooting
procedures in the
DEChub 900
MultiSwitch Owner’s
Manual.

If the power LED
turns on when the
module is reseated in
the same slot, then the
module was not
properly seated.

Make sure the module is
properly seated in the
slot.

If the power LED
turns on when the
module is reseated in
another slot, then the
problem is with the
DEChub.

See the troubleshooting
procedures in the
DEChub 900
MultiSwitch Owner’s
Manual.

If the module does not
turn on in a known
good slot, then the
module is defective.

Replace the module.

Problem Solving A-5

Problem Solving Using the LEDs
Table A-3: Problem Solving Using the LEDs
Symptom

Probable Cause

Corrective Action

Power LED is flashing.

The module
connection is faulty.

Lift the release lever,
then reseat the module.

Faulty DEChub 900
slot connection.

Reinstall the module into
another slot.

DEChub 900 power
supply is faulty.

Replace the DEChub
900 power supply.

Module does not have
sufficient power.

Ensure Power LED is
on.

Self-test is in progress.

Wait up to five-minutes
for self-test to complete.

Self-test failed.

If the LED does not light
after five-minutes, lift
the release lever
momentarily to repeat
the self-test. If self-test
fails again, replace the
module.

Non-fatal error.

See the error message on
the console port.

Fan is faulty.

Call your DIGITAL
representative to replace
the fan.

Seven-segment display
is flashing C, d, or n.

Memory failure.

Return the unit to Digital
Equipment Corporation.

Seven-segment display
is flashing or displaying
an 8.

Fatal error.

Return the unit to Digital
Equipment Corporation.

Seven-segment display
shows a 3.

There is a problem
downloading the
software. The
software will continue
to try to load.

If the display persists,
see the error message on
the console port.

Module OK LED is off.

Module OK LED is
flashing

A-6 Problem Solving

Problem Solving Using the LEDs
Table A-3: Problem Solving Using the LEDs
Symptom

Probable Cause

Corrective Action

The Network Activity
LED is off.

There is low network
activity or no network
activity.

Ensure that the network
is active. If the Network
Activity LED still fails
to turn on, then turn the
unit off momentarily by
removing it from the
power supply. Check
that the Network
Activity LED blinks
momentarily during the
LED powerup self test.

The module or another
unit in the DEChub
may not be connected
to an active segment.

Connect a known active
segment to any unit in
the DEChub.

If the module is
connected to a known
active segment and the
Network Activity
LED is off, then the
module is defective.

Replace the module.

Diagnostics has
detected a fatal error
on the modem port.

Call your DIGITAL
representative.

The Port LED is orange.

Problem Solving A-7

Problem Solving Using the LEDs
Table A-3: Problem Solving Using the LEDs
Symptom

Probable Cause

Corrective Action

After correctly installing
the module on a
DEChub 900, the
information display does
not read:

An old version of the
DECserver Network
Access Software was
loaded into the
DECserver 900MC.

Reload the DECserver
900MC with Version 2.1
or later of the DECserver
Network Access
Software.

Defective module.

Replace the module.

Defective module.

Replace the module.

DECserver 900MC
up

but the "race track"
pattern is displayed.
After correctly installing
the module on a
DEChub 900, the
information display does
not read:
DECserver 900MC
up

After correctly installing
the module on a
DEChub 900, the hub
manager does not
display configuration
information.

A-8 Problem Solving

Problem Solving Using the Seven-Segment Display

Problem Solving Using the Seven-Segment Display
This section shows the codes that appear on the seven-segment display during
power-up and initialization self-test.

NOTES
•

When the display codes are rotating, the DECserver 900MC is receiving power.
(The rotating code is referred to as the "race track" pattern.)

•

When the display codes are off, the DECserver 900MC is not receiving power or
the display is broken.

In Figure A-1, the first column indicates a horizontal view (standalone). The second
column indicates a vertical view (hub) of the codes. The third column describes the
events indicated by the codes.

Problem Solving A-9

Problem Solving Using the Seven-Segment Display
Figure A-1: Seven-Segment Display Codes

Initial power is on
Initializing
Internal testing
SIM 1 testing
SIM 2 testing
Internal testing
Internal testing
Internal testing
Internal testing
Network interface external testing
Software is loading from Flash RAM or is updating
Flash RAM
Server is requesting software from network
Attempting to retry software load
Loading software
Server is requesting a dump
Dumping software
Hardware and firmware versions are of incompatable
revisions
No SIMs or wrong type of SIMs is installed
Internal testing
LKG-8099-93I

A-10 Problem Solving

Troubleshooting Tips When Using Your Built-in Modems

Troubleshooting Tips When Using Your Built-in Modems
This section lists information to aid you when using your built-in modems. For more
information on the DECserver Network Access Software, see the Network Access
Server Release Notes. For more information on AT command syntax, see Appendix F,
AT Commands.
Symptom

Corrective Action

Modem does not connect at
33400 bps.

Your modem’s speed is limited by the type of
modem you are connecting to and the quality
of the phone lines that you use. Determine the
type of modem you are calling or answering.
For slower modems, the highest mutually
supported speed is the maximum connect
speed possible.

Modem does not dial out.

Ensure the telephone cable connections are
secure.
If the software displays NO DIALTONE,
enter the ATX3 command to make it dial
without detecting dial tone.
If you need an outside-access code, such as 9,
include it and a comma before the number
you are dialing.
Ensure that you are using ATDT for tone
dialing or ATDP for pulse phone lines.
Ensure the country code is set.

Modem does not connect.
(If it displays NO CARRIER
after dialing the number, it did
not connect.)

Use a hand-held telephone to dial the remote
modem. If the remote modem does not
answer, the problem is with the remote
modem.
Use a line that does not require an outsideaccess code.
Lower your connection speed.
Use M, Y, or A dial modifiers.
Shut off extra features using AT-J0, AT-K0,
or AT%L3.

Problem Solving A-11

Troubleshooting Tips When Using Your Built-in Modems
Symptom

Corrective Action

Modem throughput is slower
than expected.

If you are calling another Microcom V.34
modem and cannot connect at 33400 bps,
lower your modem-port speed using the
%Bn command. If your connection
succeeds, the problem is the quality of your
phone lines.
If your file transfer rate is slow, experiment
with the %Cn command for different forms
of data compression. Certain types of files are
already compressed and can cause delays as
the modem tries to compress them again.
Experiment with \Nn for different forms of
error correction. Be careful, you may
sacrifice data integrity if you turn off error
correction.

A-12 Problem Solving

Appendix B
Connector and Cable Assignments

Overview
Introduction
This appendix shows the pin assignments of the connectors and cables that are part of,
or can be used with, the module. Chapter 2, Installing the Module describes how to
connect the port cables.
The DECserver 900MC contains nine-ports, 1 asynchronous port and 8 built-in
modem ports. The asynchronous port is used as the console port and is known as Port
9 by the DECserver Network Access Software.

In This Appendix
Topic

Page

Compatible Cables for the Console Port

B-2

8-Pin MJ Console Connector Information

B-3

8-Pin MJ Telephone Connector Information

B-4

Connector and Cable Assignments B-1

Compatible Cables for the Console Port

Compatible Cables for the Console Port
This section lists and describes compatible cables for the DECserver 900MC console
port. Before connecting cables to the DECserver 900MC console ports, verify the
supported modem signals with the person managing the DECserver 900MC. This
information is necessary to determine which cables to use. For more information on
the signals, refer to the Network Access Server Management manual.
Table B-1 describes the compatible cables for the DECserver 900MC console port.
Table B-1: Compatible Cables for DECserver 900MC Console Port
Type of Cable

Description

H8585-AC MJ8 to DB25
(male) modem adapter

Use this adapter with the BN25G cable to
connect high-speed modems to the
DECserver 900MC console port.

H8585-AB MJ8 to DB25
(male) modem adapter

Use this adapter with the BN25G cable to
connect low-speed modems to the DECserver
900MC console port.

H8585-AA MJ8 to DB9
(female) null-modem adapter

Use this adapter with the DN25G cable to
convert the DECserver 900MC console port
connector to the DB9 connector for cabling to
PC asychronous ports.

H8584-AC MP8 to MMJ
adapter

Use this adapter to convert the console port to
a DECserver 300 terminal server
configuration.

BN24H MP8 to MP6 office
cable

Use this office cable to connect from the 6pin MMJ port of a terminal or printer to the 8pin MJ faceplace data connector. The BN24H
is configured with one 6-pin modified
modular plug, one standard 8-pin plug, and
crossover wiring.

BN25G MP8 to MP8
equipment cable

Use this cable as either a patch cord or an
office cable. It is configured with standard 8pin modular plugs, which connect four
unshielded twisted pairs pin-to-pin.

B-2 Connector and Cable Assignments

8-Pin MJ Console Connector Information

8-Pin MJ Console Connector Information
This section contains information on the 8-pin MJ console connector. The DECserver
900MC uses an 8-pin MJ connector on the console port, which can be configured by
the software to support the pin signals indicated in Table B-2.
Figure B-1: 8-Pin MJ Description for Console Port

NPG-8719-95F

Table B-2: DECserver 900MC Console Port Pin Assignments
Pins

Signal Name

Software
Default1

Software
Alternative

RXD GND

RXD

TXD GND

CTS or RI
(selected by the
software)

CTS

RTS or DSRS
(selected by the
software)

RTS

DSRS

TXD

DTR

DSR or DCD
(selected by the
software)

DSR

DCD

1.To change default values, refer to the Network Access Server Management manual.

Connector and Cable Assignments B-3

8-Pin MJ Telephone Connector Information

8-Pin MJ Telephone Connector Information
This section contains information on the 8-pin MJ telephone connector. The
DECserver 900MC uses an 8-pin MJ connector on Ports 1 through 8. Both MP8 and
MP6 phone cables are supported. The signal information is displayed in Table B-3.
Figure B-2: 8-Pin MJ Description for Modem Ports

NPG-8719-95F

Table B-3: DECserver 900MC Modem Port Pin Assignments
Pins

Signal Name

Telephone Interface (Tip)

Telephone Interface (Ring)

B-4 Connector and Cable Assignments

Appendix C
Product Specifications

Overview
Introduction
This appendix lists the specifications and available parts for the DECserver 900MC.

In This Appendix
Topic

Page

Product Specifications

C-2

Acoustical Specifications

C-3

Connectors

C-4

Product Specifications C-1

Product Specifications

Product Specifications
Table C-1 lists the product specifications for the DECserver 900MC module.
Table C-1: Product Specifications
Parameter

Specification

Environment
Operating Temperature1

5° C to 50° C (41 ° F to 122 ° F)

Relative Humidity

10% to 95% noncondensing

Altitude
• Operating

Sea level to 2400 m (8,000 ft)

• Non-operating

Sea level to 4900 m (16,000 ft)

Power

25.6
4.1 A,
260A,
0.1 A,

5Vdc
15Vdc
12Vdc

Physical
Height

44.45 cm (17.5 in)

Width

4.45 cm (1.75 in)

Depth

15.25 cm (6 in); 25.40 cm (10.0
in) when installed as a standalone
unit.

Weight

1.66 Kg (3.65 lb)2

Shock (Class A/B for products weighing
under 100 lbs)

10 G / 10 ms half sine pulse in
three orthogonal axes

Vibration (Class C)

5 to 200 Hz sine sweep @ 0.25 G
limited by 0.02" (0.5mm)
displacement DA* 200 to 500 Hz
sine sweep @ 0.10 G

Certification

CE, CSA, FCC, TÜV, UL, VCCI

1
For sites above 2400 m (8,000 ft), decrease the operating temperature specification by 1.8° C for each 1000
m or 3.2°F for each 3200 ft.
2 Add 1.59 Kg (3.5 lb) when attached to a DEChub ONE and 2.10 Kg (4.63 lb) when attached to a DEChub

ONE MX.

C-2 Product Specifications

Acoustical Specifications

Acoustical Specifications
Table C-2 lists the acoustical specifications measured in full conformance with ISO
9296 and ISO 7779 for the DECserver 900MC module in English.
Table C-2: Acoustics - Declared values per ISO 9296 and ISO 77791
Sound Power
Level LWAd, B

Sound Pressure Level
LpAm, dBA (bystander
positions)

Idle/Operate

DSRVX-M

5.2

DSRVX-M + DEHUA

5.4

DSRVX-M + DEF1H

5.4

Product

1. Current values for specific configurations are available from Digital Equipment Corporation
representatives (1 B = 10 dBA).

Table C-3 lists the acoustical specifications measured in full conformance with ISO
9296 and ISO 7779/DIN EN27779 for the DECserver 900MC module in German.
Table C-3: Schallemissionswerte Werteangaben nach ISO 9296 und
ISO 7779/DIN EN2777921
Schalleistungspegel
LWAd, B

Schalldruckpegel
LpAm, dBA
(Zuschauerpositionen)

Leerlauf/Betrieb

DSRVX-M

5,2

DSRVX-M + DEHUA

5,4

DSRVX-M + DEF1H

5,4

Produkt

1. Aktuelle Werte für spezielle Ausrüstungsstufen sind über die Digital Equipment Vertretungen
erhältlich. 1 B = 10 dBA.

Product Specifications C-3

Connectors

Connectors
Table C-4 lists the connectors for DECserver 900MC, DEChub ONE, and DEChub
ONE-MX.
Table C-4: Connectors for the DECserver 900MC
Connectors

Quantity

DECserver 900MC
8-pin MJ

DEChub ONE
15-pin D-Sub (AUI Connector)

DEChub ONE-MX
15-pin D-Sub (AUI)

Redundant power connector (D-Sub)

C-4 Product Specifications

Appendix D
Microcom Networking Protocol

Overview
Introduction
This appendix briefly describes each Microcom Networking Protocol (MNP) class and
its features.

In This Appendix
Topic

Page

MNP Class 10 and MNP Class 5

D-2

Other Classes of MNP

D-3

Microcom Networking Protocol D-1

MNP Class 10 and MNP Class 5

MNP Class 10 and MNP Class 5
Each built-in modem on the DECserver 900MC supports Microcom Networking
Protocol (MNP) Class 10 and MNP Class 5 Data Compression. The modem is
compatible with all Microcom MNP products. Its enhanced MNP service is completely
transparent to the user.
Table D-1 shows the features of MNP Class 10 and MNP Class 5.
Table D-1: MNP Class 10 and MNP Class 5
Class

Features

MNP Class 10

Optimizes performance when operating under poor line
conditions.
Provides compatibility with non-MNP modems.
Improves the initial connection success rate by making
multiple negotiation attempts when configured for autoreliable mode.
Uses Dynamic Transmit Level Adjustment to
automatically calculate optimal transmit levels to
compensate for cellular telephone signal distortion.
Allows the user to configure the modem to negotiate the
link at a low speed modulation, then upshift to a higher
speed at the completion of link negotiation.
Improves link performance during adverse channel
conditions by aggressive adaptive packet assembly.
Maximizes throughput by continuously monitoring the line
quality and link performance, and then dynamically
upshifting or downshifting to the optimum modulation
speed.

MNP Class 5

Provides data compression, which, combined with MNP
Class 4, allows throughput of almost twice the connection
speed.
Dynamically adjusts to the type of data being transmitted
for maximum compression efficiency.

D-2 Microcom Networking Protocol

Other Classes of MNP

Other Classes of MNP
There are several other classes of MNP. Table D-2 contains a description of each class.
Table D-2: Other MNP Classes
Class Name

Description

MNP Class 2

Uses standard asynchronous framing techniques for data
transmission and error correction. Due to this protocol
overhead, the actual throughput is less than the bps rate of
the modem.

MNP Class 3

Uses synchronous framing techniques. The modem
removes start and stop bits associated with each character
prior to transmitting by MNP. This results in a 20%
increase in performance over Class 2. Thus, the actual
throughput is greater than the modem’s bps rate.
Example:Microcom SX/2400 modems operating at Class 3
service transmits data at 2600 bps.

MNP Class 4

Uses synchronous framing techniques plus improvements
developed by Microcom: Adaptive Packet Assembly and
Optimized Data Phase. These enhancements result in better
performance for all types of connections.
Adaptive Packet Assembly automatically adjusts the size
of the data packets based on the quality of the telephone
line. When the line quality is good and there are few
retransmissions, the modem increases the packet size.
When the line quality is poor and retransmissions are
frequent, the size of the packet decreases in order to
maintain high throughput during error correction under
poor conditions.
Optimized Data Phase is the redesign of the MNP protocol
header that reduces the number of overhead bytes per data
packet.
Example:Modems operating at Class 4 service transmit data
at 2900 bps.

Microcom Networking Protocol D-3

Other Classes of MNP
Table D-2: Other MNP Classes
Class Name

Description

MNP Class 6

Allows half-duplex, fast-train high-speed reliable
connections with other MNP Class 6 modems at speeds of
4800 to 9600 bps.
Universal Link Negotiation allows the modem to
automatically connect with other MNP modems at the
highest common speed and protocol.
Statistical Duplexing adjusts the line bandwidth and data
traffic flow during reliable connections to achieve
maximum throughput, resulting in error-free transmission
over 2-wire dial-up or leased lines at effective throughputs
as high as 11000 bps on the AX/9600 Plus and 19200 bps
on the AX/9624c with data compression.

MNP Class 7

Provides Enhanced Data Compression, which combined
with Class 4 allows throughput of more than twice the
connection speed. MNP Class 7 Enhanced Data
Compression not only dynamically adjusts to the type of
data being transmitted, but allows for the probability of
character frequency, for superior compression efficiency.

MNP Class 9

Includes enhanced Universal Link Negotiation.

D-4 Microcom Networking Protocol

Appendix E
Regulatory Requirements

Overview
Introduction
This appendix contains information on regulatory requirements.

In This Appendix
Topic

Page

Regulatory Requirements

E-2

Information Requested by the Telephone Company

E-3

Canadian Department of Communications Requirements

E-4

Regulatory Requirements E-1

Regulatory Requirements

Regulatory Requirements
There are certain Telephone Company and FCC regulations that apply to the
DeskPorte FAST + modems when used within the United States and Canada. Table E1 lists these regulations.
Table E-1: Regulations for United States and Canada
Country Name

Regulations

United States and Canada

The FCC has rules that permit this device to
be directly connected to the telephone
network, using a standardized jack. Do not
use this equipment on a party or coin line.
Malfunctioning equipment may cause
damage to the telephone network. If this
device is not functioning properly,
disconnect it until the problem has been
fixed. Otherwise, the telephone company
may temporarily disconnect service.
Repair of the modem can only be carried out
by Digital Equipment Corporation. It is the
responsibility of the user requiring service to
report the need for service to Digital
Equipment Corporation.
If you encounter any problems with your
telephone after installing any new device,
disconnect the device to see if it is the source
of the problem.
The telephone company may make changes
to its technical operations or procedures. If
such changes affect the compatibility or use
of the modem, the telephone company is
required to provide adequate notice of the
changes.

E-2 Regulatory Requirements

Information Requested by the Telephone Company

Information Requested by the Telephone Company
If the telephone company requests information about the equipment connected to their
lines, you should provide them with the following information:
•

Telephone number to which the device is connected.

•

Ringer equivalence number (REN), found on the FCC sticker attached to the
device. The REN determines the number of devices which may be connected to
the same telephone number. In most areas, the sum of the RENs of all devices
connected to the same line should not exceed five. If too many devices are
attached, they may not ring properly.

•

USOC telephone jack required (RJ11, RJ41, or RJ45).

•

FCC registration number, which is found on the FCC sticker attached to the
device.

Regulatory Requirements E-3

Canadian Department of Communications Requirements

Canadian Department of Communications Requirements
The Canadian Department of Communications label identifies certified equipment.
This certification means that the equipment meets certain telecommunications network
protective, operational, and safety requirements. The Department does not guarantee
the equipment will operate to the user’s satisfaction.
Before installing this equipment, users should ensure that it is permissible to be
connected to the facilities of the local telecommunications company. The equipment
must also be installed using an acceptable method of connection. In some cases, the
company’s inside wiring associated with a single line individual service may be
extended by means of a certified connector assembly (telephone extension cord). The
customer should be aware that compliance with above conditions may not prevent
degradation of service in some situations.
Repairs to certified equipment should be made by an authorized Canadian
maintenance facility designated by the supplier. Any repairs or alterations made by the
user to this equipment, or equipment malfunctions, may give the telecommunications
company cause to request the user to disconnect the equipment.
Users should ensure, for their own protection, that the electrical ground connections of
the power utility, telephone lines, and internal metallic water pipe system, if present,
are connected together. This precaution may be particularly important in rural areas.

NOTE
Users should not attempt to make electrical ground connections themselves, but
should contact the appropriate electrician authority.

The Load Number (LN) assigned to each terminal device denotes the percentage of the
total load to be connected to a telephone loop which is used by the device, to prevent
overloading. The termination on a loop may consist of any combination of devices
subject only to the requirement that the total number of devices does not exceed one
hundred.

E-4 Regulatory Requirements

Canadian Department of Communications Requirements

Canadian EMI Limits
This digital apparatus does not exceed the Class A limits for radio noise emissions
from digital apparatus set out in the Radio Interference Regulations of the Canadian
Department of Communications.
Le présent appareil numérique n'émet pas de bruits radioélectriques dépassant les
limites applicables aux appareils numériques de la class A prescrites dans le
Règlement sur le brouillage radioélectrique édicté par le ministère des
Communications du Canada.

Regulatory Requirements E-5

Appendix F
AT Commands

Overview
Introduction
This appendix lists the modem AT commands in alphabetical order. It also contains the
commands to change or read registers and the register descriptions.

In This Appendix
Topic

Page

AT Commands

F-2

Commands to Change or Read Registers

F-62

F-63

AT Commands F-1

AT Commands

AT Commands
This section lists all the modem AT commands in alphabetical order. A command
argument printed in bold is the command default setting. In most cases, you will not
need to change the default setting.

NOTE
The A/ command is the only command not preceded by “AT” and not followed by
a carriage return.

A/ Repeat Last Command
Re-executes the last command immediately.

A Answer
Forces the modem to go off hook in answer mode, regardless of the value of register
S0. If result codes are enabled, your computer displays RING (long form) or 2 (short
form) when it receives a call.

$An Auto-Answer Auto-Logon
Performs a logon sequence (created using the $Ln command) after accepting a call
from a remote system. If the sequence is successful, a connection to the remote system
is established.
Sequences 1 to 4 are predefined and used as default logon sequences during Dial
Access Security. Sequence 5 is predefined and used for Connection Password
Security. Sequence 0 disables auto-answer auto-logon.

F-2 AT Commands

AT Commands

%An Auto-Reliable Fallback Character
Where n is an integer between 0 and 127 indicating an ASCII character (default is 0,
the auto-reliable fallback character is disabled).
Sets the ASCII character recognized as the auto-reliable fallback character on the
answering modem. In auto-reliable mode, when the modem encounters an incoming
auto-reliable fallback character from the remote system, it automatically switches to
normal mode and passes the character to the serial port. Auto-reliable fallback
character recognition stops if the modem receives a SYN character (decimal 22).

NOTE
•

Do not set n=63 or n=126. These settings interfere with V.42 negotiations.

•

With this command, \N3\C2 must also be set.

*A Request Remote Access
Initiates a request for remote access. When you type AT*A the requesting modem
waits 10 seconds for a response from the answering modem. If that modem denies
remote access, the requesting modem displays REMOTE ACCESS FAILED (numeric
40) and returns to command state.
This command automatically sends the character set by *S. For the *A command to be
successful, *S must be set the same on both modems.

NOTE
Register S12 (guard time) should be set to the same value on both modems. If
register S12 is set to a value greater than 127, the requesting modem waits up to
20 seconds for a response to a remote access request. Remote access is available
only during a normal connection or during an MNP reliable connection without
data compression.

AT Commands F-3

AT Commands

\An Maximum MNP Block Size
Sets maximum block size for MNP stream link connections.
0 = Sets block size up to a maximum of 64 characters
1 = Sets block size up to a maximum of 128 characters
2 = Sets block size up to a maximum of 192 characters
3 = Sets block size up to a maximum of 256 characters

-AnAuto-Retrain Threshold
Sets the maximum number of times the modem can auto-retrain, where n = 0 to 255
(Default = 0).

Bn ITU-T/Bell Mode
0 = Uses ITU-T V.22 and V.21 standards at 1200 and 300 bps
1 = Uses Bell 212A and 103 standards at 1200 and 300 bps

$Bn Serial Port Bps Rate
Where n = 75, 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 bps
Sets the serial port bps rate when issued.

%Bn Modem Port Bps Rate
Where n = 75, 300, 600, 1200, 2400, 4800, 7200, 9600, 12000, 14400, V14400, 16800,
19200, 21600, 24000, 26400, 28800, 33600 bps
When you enter this locally, sets the modem port bps rate. Downshifting can still take
place.
When you enter this during a remote access session, the new modem port bps rate does
not take effect until the current connection ends.
If %G0 is set, an AT issued locally causes the modem port speed to match the serial
port speed, regardless of any previous %B setting.
If %G1 is set, the modem speed is changed only when you enter a %Bn command.
Entering %F1, %F2, or %F3 causes the modem to change to either split speed or 1200
bps.

F-4 AT Commands

AT Commands

\Bn Transmit Break
Where n is an integer between 1 and 9 indicating the time (in increments of 100
milliseconds) to send the Break. (Default is 300 milliseconds). During a reliable link
the Break always equals 300 milliseconds
Transmits a Break to the remote system from command state. To return to connect
state, type ATO. (See also \K.)

%CnCompression Control
%C0

Disables data compression.

%C1

Enables MNP Class 5 Data Compression only.

%C2

Enables V.42bis compression only.

%C3

Enables both V.42bis and MNP Class 5 compressions. The modem matches the
capability of the remote modem.
Determines whether the modem attempts to use data compression during reliable
connections. We recommend leaving this command at its default setting (%C3). This
allows the modem to establish a reliable connection using either MNP Class 5 Data
Compression or V.42bis compression, depending on the capability of the remote
modem. Setting this command to 1 or 2 restricts the modem to using either MNP Class
5 Data Compression or V.42bis compression, respectively, otherwise a noncompression connection results.
If the remote modem does not support data compression or has data compression
disabled, the modem can establish a connection without data compression, regardless
of the modem’s %C setting.

NOTES
•

We recommend disabling bps rate adjust (\J0) for the most throughput. When bps
rate adjust (\J1) is set and the modem establishes a reliable connection at speeds
between 4800 and 14400 bps, the serial port adjusts to 9600 bps. If the connection
speed is above 14400 bps, the serial port adjusts to 19200 bps.

•

Remote access is available during normal connections or during MNP reliable
connections when data compression is disabled (%C0).

AT Commands F-5

AT Commands

&CnSerial Port DCD Control
&C0

DCD always On.

&C1

DCD follows the state of the carrier from the remote system; DCD turns On after the
connect message.

&C2

DCD On except momentarily at disconnect.
Controls the Carrier Detect (DCD) signal on the serial port. Use this command if your
computer requires DCD to be Off at certain times. See also the \D command
description.

NOTE
The &C and \D settings are ignored while connected in V.23 half-duplex direct
mode (%F3) or ITU-T V.13 (&R2). Hardware flow control overrides the &C and
\D settings for CTS operation. (See also \Q.)

@CnCTS, DSR, and DCD Connect Message Control
@C0

CTS, DSR, and DCD On after the connect message is sent.

@C1

CTS, DSR, and DCD On before the connect message is sent.
Specifies whether CTS, DSR, and DCD go On before or after a connect message. Use
this command with :T14.

\CnAuto-Reliable Buffer
\C0

Does not buffer data during link negotiation. Switches to normal or direct mode if no
SYN character detected within 3 seconds.

\C1

Buffers all data on the answering modem until it receives either 200 non-SYN
characters or a SYN character within 3 seconds (this delay is longer for modem speeds
300 or below). If it receives 200 non-SYN characters, the modem switches to normal
mode and passes the data through to the serial port. If it detects a SYN character within
3 seconds, it attempts to establish a reliable connection. Otherwise, it switches to
normal mode.

\C2

Does not buffer data on the answering modem. Switches to normal mode upon receipt
of a character defined by the AT%A command and passes that character to the serial
port.

F-6 AT Commands

AT Commands
Determines whether the answering modem set to auto-reliable mode and auto-answer
buffers data from the remote modem during the 3 seconds when it tries to establish a
reliable connection. When the modem receives calls both from modems that support
MNP and from modems that do not, set \C2. This allows the modem to switch to
normal mode as soon as it detects a log-on character (defined by %A) from a non-MNP
caller. This eliminates the 3-second wait. (See the \N command description for more
information about auto-reliable and normal modes.)
For example, use %A to set the auto-reliable fallback character to ASCII 13 (carriage
return). Then set \C2\N3. Non-MNP callers who connect and press to log on do not
have to wait for the 3-second auto-reliable window to expire before data can pass.

NOTES
When either \C1 or \C2 is set, reliable and normal connections may result
independently of bps rate adjustments. However, when \C0 is set, bps rate adjustments
affect the type of connection as follows:
•

reliable and direct connections may result when bps rate adjust is On (\J1)

•

reliable and normal connections may result when bps rate adjust is Off (\J0)

When falling back to V.23 full duplex connections and either \C1 or \C2 is set, reliable
and normal connections may result independently of the \W command. However,
when \C0 is set, the split serial port speed affects the type of connection as follows:
•

direct connections result when split speed is enabled (\W1)

•

normal connections result when split speed is disabled (\W0)

When either \C0\N3 or \C1\N3 are set, the modem takes approximately 12
seconds to drop to a normal mode V.21 connection.

AT Commands F-7

AT Commands

D <dial string> Dial
Where <dial string> is a string of up to 98 characters. Valid dial string characters are:
0-9, dial modifiers, and for tone dialing A, B, C, D, #, and *. The modem ignores
invalid characters. Dial strings longer than 98 characters produce an error message.
Dials a telephone number and attempts to establish a connection. The Dial command
must be the last one on a command line.
To cancel the Dial command, press any key or use your data communications software
to lower DTR (unless &D0 is set).
Example

To dial the telephone number 011 22 555 1234, type:
ATD 011225551234

NOTE
After disconnect, there is a five second delay before the modem goes off hook in
originate mode.

Dial Modifiers
Dial modifiers allow you to add conditions to the telephone number you dial. You can
use several modifiers with the same telephone number. Dial modifiers include:
J

(Link Negotiation) Perform link negotiation at 1200 bps for the current connection
only. (This dial modifier is equivalent to the *H1 command.)

(Cell-Side Cellular Connection) Sets M1 for the current connection only.

(Dial an Alternate Stored Number) Follows the last character in a dial string and, if the
modem fails to make a connection, the Nn modifier dials an alternate telephone
number. n is a two-digit number between 01 and 40 that corresponds to a telephone
number stored in the directory with the &Zn or \Pn command.

Example

ATD 5551234N03
If you do not enter a value for n, the modem dials the first stored entry.
You can also store the Nn modifier at the end of the dial string. If you do not specify
any value for n at the end of a stored phone number and the modem fails to make a
connection, it dials the number in the next position. Stored number 01 follows stored
number 40.

Example

AT\P04 5551234N03

F-8 AT Commands

AT Commands
O

(Cell-Side Cellular Call) Sets the modem to operate with a cell-side (remote) cellular
phone, for the current connection only. This has the same effect as including the
cellular string \N2)M1:E0@M18*H1 in the dial command. These settings use the
MNP reliable mode, force power adjustment for cell-side calls, select an initial
transmit level of -18 dBm, and force link negotiation to occur at 1200 bps.
NOTE
This modifier is unnecessary for land-side (central) sites. Your modem
automatically adjusts to incoming cellular calls.

(Pulse Dial) Placed anywhere in the dial string, causes the modem to pulse dial the
number.

Example

ATD P5551234
Tone dial is the default setting. The last P or T dial modifier used remains in effect until
you either issue a dial command with a different P or T modifier or reset the modem.
Also, you can combine P and T dial modifiers within a dial string.

Example

Pulse dial a local telephone number and tone dial an access code and telephone number
by typing: ATD P5551234 T33 5556789

(Dial a Number in Answer Mode) Must follow the last character in the dial string.
Causes the modem to dial in answer mode when calling an originate-only modem.

Example

ATD 5551234R

(Dial the First Stored Telephone Number) Follows the Dial command and causes the
modem to dial the telephone number stored as entry 01 with the &Z01 or \P01
command. The telephone number displayed as the modem dials it.

Example

ATDS

(Tone Dial) Placed anywhere in the dial string, causes the modem to tone dial the
number.

Example

ATD T12345

NOTE
Tone dial is the default setting. The last P or T dial modifier used remains in effect
until you either enter a dial command with a different P or T modifier or reset the
modem. You can combine P and T dial modifiers within a dial string.

AT Commands F-9

AT Commands
Example

Pulse dial a local telephone number and tone dial an access code and telephone number
by typing: ATD P5551234 T33 56789

(Wait for Dial Tone Before Dialing) Inserted between digits in a dial string, causes the
modem to wait for a second dial tone up to the register S7 time delay before dialing the
number. If the modem receives a dial tone before the register S7 delay expires, it
continues dialing. If it does not receive a dial tone, it displays NO DIALTONE and
hangs up.

Example

ATD 5551234 W 5556789

(Link Negotiation) Perform link negotiation at 4800 bps for the current connection
only. (This dial modifier is equivalent to the *H2 command.)

(Pause During Dial) Inserted in a dial string, causes the modem to pause for the register
S8 delay before dialing the next digit. The default is 2 seconds. Use more than one
comma for a longer pause.

Example

When you need to dial {9} and pause for another dial tone before dialing an outside
line, do the following: ATD 9,,5551234

(Wait for Quiet Answer Before Dialing) Inserted between characters in a dial string
and causes the modem to wait for the register S7 time delay, for at least one ring
followed by five seconds of silence, before acting on the next character in the dial
string. If the modem does not detect this sequence, it displays NO ANSWER and hangs
up. Use this modifier when the system you are calling does not provide a dial tone.

Example

ATD 5551234 @ 43210

(Flash) Inserted between characters in a dial string, causes the modem to go on hook
for 1/2-second and then go back off hook, as though you depressed the switch-hook
button on your telephone.

;

(Return to Command State After Dialing) Added to the end of a dial string, tells the
modem to remain in command state after it dials the digits preceding the semicolon.
This lets you enter dial strings longer than 98 characters. After the final Dial command,
the modem tries to establish a connection. To abort dialing before you attempt to make
a connection, type ATH. Each Dial command except the last one must end with a
semicolon.

Example

ATD 9,5551234;
OK
ATD 5556789 @ 55512345678 W 344

(Force Logon Sequence) Dial, connect, and perform the logon sequence n (where n=19).

Example

To perform sequence 1, type: ATD5551234+1

F-10 AT Commands

AT Commands
$

(Bong Detect) Detects an AT&T BELLCORE service prompt to enter a calling card
number and authorization. When the modem encounters a “$” modifier within a dial
string, it waits to receive this “bong” signal. Once it detects it, the modem continues
processing the dial string. If the time set by register, S7 elapses first, the modem hangs
up and displays NO PROMPT TONE.
NOTE
This modifier is valid only in the United States, Canada, Mexico, and Israel.

Operating Mode Dial Modifiers
Use the following dial modifiers to override the \Nn command setting. Placed
anywhere in the dial string, these modifiers cause the modem to override the \Nn
setting for that connection only.
Example

If your modem is set for \N3 (auto-reliable) for answering and you are calling a modem
that you know does not support error correction, use the Z dial modifier to force normal
mode: ATD 5551234Z

(Dial in LAPM Mode) Placed anywhere in the dial string, causes the modem to
override the current operating mode and dial in LAPM reliable mode for the current
connection only.

(Dial in LAPM Mode with Fallback to Normal) Placed anywhere in the dial string,
causes the modem to override the current operating mode and dial in LAPM reliable
mode with fallback to normal mode for the current connection only.

(Dial in Direct Mode) Placed anywhere in the dial string, causes the modem to override
the current operating mode and dial in direct mode for the current connection only.

(Dial in LAPM Mode with Fallback to MNP) Placed anywhere in the dial string,
causes the modem to override the current operating mode and dial in LAPM reliable
mode with fallback to MNP for the current connection only.

(Dial in Auto-Reliable Mode) Placed anywhere in the dial string, causes the modem to
override the current operating mode and dial in auto-reliable mode for the current
connection only.

(Dial in MNP Reliable Mode) Placed anywhere in the dial string, causes the modem to
override the current operating mode and dial in MNP reliable mode for the current
connection only.

(Dial in Normal Mode) Placed anywhere in the dial string, causes the modem to
override the current operating mode and dial in normal mode for the current connection
only.

AT Commands F-11

AT Commands

DL Redial the Last Telephone Number Dialed
Redials the last telephone number that the modem dialed.

D/n Dial a Stored Telephone Number
Where n is a two-digit integer between 01 and 40 that specifies a telephone number
previously stored in the directory with the &Zn= or \Pn command.
Dials one of 40 telephone numbers stored in the directory with the &Zn= or \Pn
command. The telephone number is displayed as it is dialed.

$D Power-Up Diagnostics
Performs power-up diagnostics. Also, when all switches in both banks are up, performs
a reset and power-up diagnostics continuously.

%Dn Disconnect Buffer Delay
Where n is an integer from 0 to 255 representing seconds (Default is 0).
Sets a delay during which the modem attempts to process data in its transmit or receive
buffer before disconnecting. When your software lowers DTR or you type ATH, the
modem attempts for n seconds to empty its transmit buffer before disconnecting. When
carrier drops, the modem attempts for n seconds to empty its receive buffer before
disconnecting. If its buffers are empty or if n=0, the modem disconnects without delay.
If a physical disconnect occurs (for example, the connection drops from too many
retransmissions in reliable mode), the modem can process only the receive buffer. If
the delay expires before the modem empties its buffers or it is in command state at
disconnect, it may loose data.

&Dn DTR Control
&D0

Ignores DTR. DTR is not needed for auto-answer.

&D1

Enters command state on detecting On-to-Off transition of DTR; DTR is not needed
for auto-answer.

&D2

Goes on hook on detecting On-to-Off transition of DTR and prepares the serial port to
accept an AT at any speed. DTR is needed for auto-answer.

&D3

Goes on hook and resets on detecting On-to-Off transition of DTR and prepares the
serial port to accept an AT at any speed. DTR is needed for auto-answer.
The On-to-Off transition of DTR must last as long as the value specified in register S25
(default is 0.05 second). Positive transitions of DTR (Off-to-On) that occur within five
seconds after disconnect are ignored.

F-12 AT Commands

AT Commands

-D Repeat Dial
-D <dial string> Where <dial string> is a string of up to 98 characters. Valid dial string characters are:
0-9, dial modifiers, and for tone dial, #, A, B, C, D and *. The modem ignores invalid
characters.
-D/n

Where n is a two-digit integer between 01 and 40 that specifies a telephone number
previously stored with \Pn.

-DL

Redials the last number dialed.

-DS

Dials the first entry stored in the directory.
Redials a number up to 9 tries until connection. In reliable mode, it does not redial if a
remote modem answers but fails to establish a reliable connection.

:Dn Manual Dial
:D0

Modem does not go off hook when DTR is raised.

:D1

Modem goes off hook in originate mode when DTR is raised. &Dn (where n=1, 2, or
3) must also be set.

:D2

Modem goes off hook in originate mode and dials the first stored telephone number
when either DTR is raised or the T/D button is pressed. &Dn (where n=1, 2, or 3) must
also be set. The O/A button must be in originate mode (not lit).
Determines whether modem goes off hook in originate mode if DTR is raised.

NOTE
When :D1 or :D2 is set, register :T18 must be set to 0.

\Dn Serial Port DSR/CTS Control
\D0

DSR and CTS are always On.

\D1

DSR and CTS follow DCD. If &C1 is also set, DSR follows off hook.

\D2

DSR and CTS both follow DCD.

\D3

DSR complies with ITU-T recommendations, CTS is always On.

\D4

DSR and CTS comply with ITU-T recommendations.
Controls the Data Set Ready (DSR) and Clear To Send (CTS) signals on the serial port.
Use this command when the central-site computer requires the DSR and CTS signals
to be Off at specific times.

AT Commands F-13

AT Commands

NOTES
•

Hardware flow control overrides &C and \D settings for CTS. (See \Q.)

•

The modem ignores &C and \D settings while connected in V.23 half-duplex
direct mode (%F3) or ITU-T V.13 (&R2).

•

When \D4 is set, &D should be set to a value greater than 0.

•

ITU-T recommends that DSR comes On when establishing a connection and
drops when the connection ends.

•

ITU-T recommends that CTS follows DTR while in command state; drop either
when answer tone is detected when originating, when going off hook when
answering, or when connection ends; and follows connection status during
connection.

Use the following table when your computer requires DSR and CTS to be Off. It shows
&C and \D settings and the result of combining the two commands.
&C

Result

DCD On, DSR On, CTS On

DCD On, DSR complies with the ITU-T
recommendations, CTS On

DCD On, CTS/DSR comply with the ITU-T
recommendations

DCD follows modem carrier, DSR On, CTS On

DCD follows modem carrier, DSR follows off hook,
CTS follows DCD

DCD follows modem carrier, DSR and CTS both
follow DCD setting

DCD follows modem carrier, DSR complies with the
ITU-T recommendations, CTS On

DCD follows modem carrier, CTS/DSR comply with
the ITU-T recommendations

F-14 AT Commands

AT Commands
&C

Result

DCD On (Off for a few seconds at disconnect only),
DSR On, CTS On

DCD, DSR, and CTS On (Off for a few seconds at
disconnect)

DCD Off at disconnect then On, DSR complies with
the ITU-T recommendations, CTS On

DCD On (Off for a few seconds at disconnect), CTS/
DSR comply with the ITU-T recommendations

En Command Echo
E0

Inhibits the echoing of commands to the local device.

Echoes commands to the local device.

%En Auto-Retrain
%E0

Disables the automatic retrain sequence.

%E1

Enables the automatic retrain sequence (at 2400 bps or higher).
When %E1 is set and line quality is too poor to sustain communications, the modem
tries up to three times to resynchronize the modems (for a total of up to six seconds)
before hanging up. The TST indicator lights during auto-retraining. The modem can
retrain during connections at 2400 bps or higher. Use ATO1 to force the retrain
sequence when %E0 is set.

NOTE
The modem ignores %E0 during V.34, V.32bis and V.32 connections.

AT Commands F-15

AT Commands

*En Enable Remote Access
*E0

Disables remote access.

*E1

Enables remote access.
Determines how the modem responds to a request for remote access. Remote access is
available only during a normal connection or during an MNP reliable connection
without data compression.

NOTE
The modem does not support remote access during LAPM reliable connections.

-En Modem Port Data Length
-E0

Enables 10-bit data during normal mode connections.

-E1

Enables 11-bit data during normal mode connections.
Determines the number of data bits used on the modem port during normal mode
connections (when \N0 is set) when the serial port is configured for asynchronous
transmission of 11-bit characters. Both modems must be set to the same number of data
bits.

NOTE
The modems will not be able to pass data when a reliable connection (\N3 or \N5
is set) falls back to a normal connection with 11-bit data characters enabled on
both modems.

.:En Compromise Equalizer
:E0

Disables the compromise equalizer only when the modem is in V.32bis or V.32 mode;
may be useful for direct line connections or PBX-to-PBX connections.

:E1

Enables the compromise equalizer; may be useful for outside-line-to-outside-line or
PBX-to-outside-line connections.
Controls equalization operation when the modem connects in V.32bis or V.32.

F-16 AT Commands

AT Commands

\En Data Echo
\E0

Does not echo data sent by the local computer.

\E1

Echoes data sent by the local computer.
When operating in connect state, determines whether the modem echoes characters
sent from the local computer. \E1 functions only during normal mode connections.

%Fn V.23 Mode
%F0

Allows multi-protocol answering; disables V.23 mode on originating modem.

%F1

75 bps transmit, 1200 bps receive (split speed) V.23 operation.

%F2

1200 bps transmit, 75 bps receive (split speed) V.23 operation.

%F3

1200 bps transmit, 1200 bps receive (half duplex) V.23 operation.
Determines the V.23 mode used at 1200 bps. You can configure either channel with
the %Fn command for transmitting or receiving data. For split-speed operation, the
originating and answering modems must be set to opposite V.23 split-speed mode
command settings: set %F1 on the modem transmitting at 75 bps and %F2 on the
modem transmitting at 1200 bps. For example, if you set your modem to transmit data
at 1200 bps and receive data at 75 bps, it can establish a V.23 connection only with a
remote modem that transmits data at 75 bps and receives data at 1200 bps.

NOTE
Typing AT%Fn (where n=1, 2, or 3) disables all protocols except V.23. Typing
AT%Bn forces the %F0 setting.

During normal split-speed connections:
•

Set \J0 to operate at the speed of the serial port prior to the connection.

•

Set \J1 for a 1200 bps constant speed.

During direct connections, the computer must also be able to accommodate split
transmit and receive speeds. For other connections, you can use \Wn to control serial
port speed.
V.23 half-duplex operation is available only for direct and normal connections. V.23
half-duplex connections should have %F3 set on both modems.

AT Commands F-17

AT Commands

NOTES
•

The connect message displayed when a V.23 half-duplex connection is
established is CONNECT V.23 HDX.

•

The connect message displayed when a V.23 split-speed connection is established
is CONNECT V.23.

•

When the originating modem is set to normal mode, you must send a few
characters to the answer modem before the modem can fall back to a V.23 halfduplex connection.

When %F0 is set and the modem is at 1200 bps or higher, it can answer as a V.23 1200/
75 bps modem or a V.23 1200/1200 bps half-duplex modem.
When %F3 is set, the modem can only establish normal or direct 1200 bps half-duplex
connections.
The \S command shows MODEM BPS V.23 when the modem establishes a V.23
connection.
This section lists the commands to configure the modem for each modulation protocol
and mode. Modem connection speeds are in parentheses.
When %F1, %F2, or %F3 is set for V.23 connections:
Protocol

Command

V.23 (TX 75 bps/RX 1200 bps)
Split Serial Port Speed

%F1\W1

V.23 (TX 75 bps/RX 1200 bps)
Constant Serial Port Speed

\W0%F1\J0

V.23 (TX 1200 bps/RX 75 bps)
Split Serial Port Speed

%F2\W1

V.23 (TX 1200 bps/RX 75 bps)
Constant Serial Port Speed

\W0%F2\J0

V.23 (1200 bps half duplex)

%F3

F-18 AT Commands

AT Commands

NOTES
•

If a direct connection results, the computer must be set to split speed to match the
modem speeds.

•

All V.23 connections are available only for direct and normal connections.

&F Restore Factory Defaults
First restores the factory default settings and, if Bank 2, Switch 5 is up, sets the options
selected by the configuration switches. Stored telephone numbers are preserved.

-Fn Secondary Flow Control
-F0

Disables secondary flow control characters.

-F1

Enables secondary flow control characters.
Controls whether the modem sends or receives secondary flow control characters on
the serial port. When -F1 is set and primary flow control enabled on the serial port, the
modem sends two flow control characters (one primary and one secondary) to the host
for flow control processing.
If the modem receives either a primary or secondary XOFF flow control character, it
stops sending data until it receives the corresponding primary or secondary XON
character.

\F Read Stored Phone Numbers
Displays the telephone numbers currently stored in the telephone directory. To cancel
a display, issue a Break with your data communications software.

$Gn Dial Access Security
$G0

Disables Dial Access Security.

$G1

Enables Dial Access Security.
Controls whether the modem uses Dial Access Security during logon. If you also want
the modem to auto-answer, set register S0=1.

AT Commands F-19

AT Commands

%Gn Independent Serial Port/Modem Port Speed
%G0

Serial port speed determines modem port speed.

%G1

%B command determines modem port speed.
Determines whether the modem port speed updates to match the serial port speed with
each AT command. When %G1 is set, the modem port speed does not update, and you
must change it with a %B or %Fn command.
When you send an AT command string to the modem, it adjusts its modem port speed
automatically to match the AT speed. You can disable this feature with %G1. When
%G1 is set, you can change the modem speed with the %Bn (where n is the new
modem speed) and %Fn commands.
This section lists the commands to configure the modem for each modulation protocol
and mode. Modem connection speeds are in parentheses.
Protocol

When %F0 is set:
Issue %G0:

Issue %G1:

V.21 (75-300 bps)

B0 at 300 bps

B0%B300

Bell 103 (75-300 bps)

B1 at 300 bps

B1%B300

V.22 (600 bps)

at 600 bps

%B600

V.22 (1200 bps)

B0 at 1200 bps

B0%B1200

Bell 212A (1200 bps)

B1 at 1200 bps

B1%B1200

V.22bis (2400 bps)

at 2400 bps

%B2400

V.32 (4800 bps)

at 4800 bps

%B4800

V.32 (7200 bps)

at 7200 bps

%B7200

V.32 (9600 bps)

at 9600 bps

%B9600

V.32bis (12000 bps)

at 12000 bps

%B12000

V.32bis (14400 bps)

at 14400 bps

%B14400

V.34 (14400 bps)

at 14400 bps

%BV14400

V.34 (16800 bps)

at 16800 bps

%B16800

V.34 (19200 bps)

at 19200 bps

%B19200

V.34 (21600 bps)

at 21600 bps

%B21600

V.34 (24000 bps)

at 24000 bps

%B24000

F-20 AT Commands

AT Commands
Protocol

When %F0 is set:
Issue %G0:

Issue %G1:

V.34 (26400 bps)

at 26400 bps

%B26400

V.34 (28800 bps)

at 28800 bps

%B28800

NOTE
For the modem to achieve the highest possible throughput available, set the
modem port speed by typing AT%G1%Bn (where n equals the desired speed).

&Gn Guard Tone
&G0

Disables guard tone.

&G1

Sets guard tone on the answering modem to 550 Hz.

&G2

Sets guard tone on the answering modem to 1800 Hz.
NOTE
Outside the United States and Canada, some phone systems require a modem to
send a guard tone after an answer tone.

AT Commands F-21

AT Commands

\Gn Modem Port Flow Control
\G0

Disables modem port flow control.

\G1

Sets modem port flow control to XON/XOFF.

\G2

Sets modem port flow control to unidirectional XON/XOFF.
Sets the flow control method used to pace data between modems during a normal mode
connection. When \G1 is set, the modem sends an XOFF character to stop receiving
data, and sends an XON character to resume. When \G2 is set, the modem sends XON
and XOFF characters to the remote device but ignores XON and XOFF characters
from the remote device.

NOTES
•

The reliable mode has its own method of flow control and ignores the \G setting.
However, \Qn settings remain active.

•

Both modems must have the same primary flow control characters set during
normal connections. (See the :T9 and :T10 register descriptions.)

H Hang Up
H0

Disconnects from the remote system and hangs up the telephone line.

Disconnects from the remote system and goes off hook in command mode.
The modem ignores positive transitions of DTR for five seconds after disconnecting.

NOTE
If %D is set to a value other than 0, hang up may not occur immediately.

$Hn Edit Dial Access Security Database
Where n=1-40 indicates a position in the Dial Access Security database. Allows the
security administrator to enter valid users and passwords.

F-22 AT Commands

AT Commands

)Hn Automatic Dial Connection Restoral Timer
Where n is an integer from 0 to 255 minutes (Default is 0 (disabled)).
When a connection fails, specifies how long the local modem tries to re-establish the
physical data link with the remote modem. It also specifies how long the remote
modem waits for the local modem to re-establish the link. If the modems do not
establish a new connection in the time specified by )H, they disconnect.
This command is only valid during MNP reliable connections. It must be set on both
modems. If flow control is enabled, the modems stop receiving data from the host until
the time specified by )H expires or until a connection is reestablished.

NOTE
Your modem will try 9 redials (see the -D command), so do not set )H greater than
2.

*Hn Link Negotiation Speed
*H0

Link negotiation occurs at the highest supported speed.

*H1

Link negotiation occurs at 1200 bps.

*H2

Link negotiation occurs at 4800 bps.
Sets the connection speed for link negotiation for connections before upshift occurs
between two MNP Class 10 modems. Use the *H1 or *H2 setting to set the connection
speed to 1200 or 4800 bps, respectively, to facilitate link negotiation over poor
telephone lines.

-Hn Dumb Mode
-H0

Disables dumb mode (sets smart mode).

-H1

Enables dumb mode.
Used to configure the modem to ignore commands and not send result codes. The
modem is in smart mode when it recognizes commands.

NOTE
If you set dumb mode, you can reset the modem to accept AT commands by
turning it off and on.

AT Commands F-23

AT Commands

\Hn Hewlett Packard ENQ/ACK
\H0

HP ENQ/ACK protocol disabled.

\H1

HP ENQ/ACK protocol enabled during MNP reliable link; modem emulates terminal.

\H2

HP ENQ/ACK protocol enabled during MNP reliable link; modem emulates host.
Hewlett Packard ENQ/ACK support allows the modem to emulate the ENQ/ACK
protocol when an MNP reliable link is established. Flow control may be used in
addition to the ENQ/ACK protocol if the host or terminal supports it. Each data block
should not exceed 250 characters. To use the HP ENQ/ACK protocol:
•

Set the modem at the host to \H1.

•

Set the modem at the terminal to \H2.

•

Enable either XON/XOFF (\Q1) or hardware (\Q3) flow control on the serial port
on both modems to prevent data loss.

•

Establish an MNP reliable link.

NOTE
The modem does not support HP ENQ/ACK protocol during V.42 LAPM reliable
connections.

^H Host Port Upgrade
Installs new firmware from a computer file to the modem’s flash memory.
NOTE
This is part of the memory update operations.

In Identification ;
I0

Displays the 4-digit modem product code.

Performs a checksum on the firmware ROM and displays the 3-digit result.

Performs a checksum on the firmware ROM and displays the checksum status, which
should display OK.

Displays modem name and revision.

F-24 AT Commands

AT Commands

$I Display Dial Access Security Database
Allows the security administrator to display the Dial Access Security database.

%In Edit Connection Security Password (Asynchronous Mode)
Edit Connection Security password n, where n = 0 to 49. (Default is no password.)
Allows the security administrator to set a new password or change the existing
password. Passwords set by this command are verified during link negotiation by using
the $M command.
You can password protect the Connection Security password with the $P command. If
a password exists and has not been entered within the last two minutes, the modem
prompts you for this password first. Then it asks you for the Connection Security
password at the NEW PASSWORD: prompt.

NOTE
If the logon sequence has no password protection, then any user can set a new
password or edit an existing one by using the %I command.

Passwords must contain exactly five alphanumeric characters. The modem ignores
upper case or lower case and parity. You must type the old password correctly to enter
a new password. You must type the new password the same way both times for it to
take effect. Periods echo as you type the password.
You can enter up to fifty passwords for both the originating and answering modems
(see %In, where n = 0 to 49). During link negotiation, the originating modem sends
password 0 to the answering modem when $M1 is set. The answering modem checks
its list of passwords to see whether the password matches any of its passwords 0 though
49. If there is a match, the connection proceeds. If not, the connection fails. When $M2
is set on the answerer, if the originator’s password does not match one of the
answerer’s passwords, the answerer uses auto-logon string 5 to prompt the remote user
(up to three times) for the Connection Security password. If the Auto-Logon sequence
fails, the connection fails.

AT Commands F-25

AT Commands
Default sequence 5 is:
D2A20’ Connection Password:’ P2 ’^M^J’Z
Where:

Means:

D2A20 ’Connection
Password:’P2

send the string Connection Password: to the remote user
and wait for a string containing the user’s password. Echo
periods to the remote user. If a string is not received within
20 seconds, abort and disconnect.

'^M^J'

send a carriage return and a line feed.

check the Connection Security Password Database for the
password. If there is a match, the connection proceeds. If
no match, retry the sequence up to two times more (for a
total of three tries), then disconnect.

%In;ppppp;sssssEdit Connection Security Password
(V.25bis Synchronous Mode)
Edit Connection Security password n, where n = 0 to 49, ppppp is the Security
Database Password, and sssss is the Connection Security Password.
Allows the security administrator to set a new password or change the existing
password. If you set $M1 or $M2, the modem verifies passwords set by this command
during connection establishment.
You can password-protect the Connection Security password with the $P command. If
a Security Database Password exists, you must enter it accurately for the new
Connection Security Password to take effect. If there is no Security Database
Password, you can just enter the two semicolons and new Connection Security
Password.
Passwords must contain exactly five alphanumeric characters. The modem ignores
upper case or lower case and parity.
You can enter up to fifty passwords for both the originating and answering modems
(see %In, where n = 0 to 49). During connection establishment, the originating modem
sends password 0 to the answering modem. The answering modem checks its list of
passwords to see whether the password matches any of passwords 0 to 49. If there is a
match, the connection proceeds. If not, the connection fails.

F-26 AT Commands

AT Commands

*I Modem Identifier
Sets the modem identifier that displays as part of the remote access session banner.
You can also display the identifier with the \S command. When you enter the *I
command, the ID: prompt appears.
The identifier can consist of up to 25 ASCII characters. It truncates after the twentyfifth character. There is no default setting for the *I command.

$Jn Clear Dial Access Security Database, Stored Telephone Numbers,
and Connection Security Password Database
$J0

Clears the Dial Access Security database and restores the factory default auto-logon
sequences $L1 - $L5.

$J1

Clears the Dial Access Security database, restores the factory default auto-logon
sequences $L1 - $L5, and clears the Connection Security Password Database. Also,
clears stored telephone numbers from the modem’s telephone directory and clears the
last dialed number.
WARNING
AT$J1 is a very powerful command. It clears all passwords from the modem’s
security databases and all stored telephone numbers.

-Jn Detect Phase
-J0

Disables the detect phase.

-J1

Enables the detect phase.
Indicates whether the originating modem sends the V.42 control sequence to the
answering modem to determine the type of error correction it has enabled. The
answering modem can have LAPM, MNP, or no error correction enabled. See the \N
command description for the types of connections.

AT Commands F-27

AT Commands

\Jn Bps Rate Adjust
\J0

Disables the bps rate adjustment feature.

\J1

Enables the bps rate adjustment feature.
After establishing a connection with \J1 set, the modem automatically adjusts its serial
port speed to match the connection’s speed until that connection terminates. If your
computer does not automatically change to the adjusted bps rate, you must manually
change the bps rate to the new setting. When \J0 is set, the serial port rate is
independent of the rate of the connection.
When the modem establishes a reliable connection at speeds between 4800 and 14400
bps with bps rate adjustment enabled, the serial port speed adjusts to 9600 bps. If the
connection speed is above 14400 bps, the serial port adjusts to 19200 bps. If you set
the serial port to the modem’s highest rate of 115200 bps, turn off bps rate adjustment
to make sure that the serial port stays at 115200 bps.

NOTES
•

Refer to the %F command description for information about using the \J command
during V.23 connections.

•

See the %Un command for information about resetting the serial port bps rate.
When \J1\C0\N3 are set, the modem uses direct mode instead of normal mode if
a reliable connection is not established.

We recommend turning off bps rate adjust (\J0) when you use data compression to
retain the highest throughput.

$Kn Disable Switch Banks
$K0

Enables all configuration switch banks.

$K1

Disables switches.

F-28 AT Commands

AT Commands

-Kn MNP Extended Services
-K0

Disables MNP Extended Services.

-K1

Enables MNP Extended Services.

-K2

Enables MNP Extended Services without MNP indication during the answer detect
phase.
MNP Extended Services allow two modems that support them to use MNP data
services that are not available with LAPM. For example, two modems with MNP
Extended Services enabled will negotiate MNP Class 10 with V.42bis compression in
preference to LAPM.

:Kn Kermit/UUCP Protocol
:K0

Disables Kermit and UUCP spoofing asynchronous protocols.

:K1

Enables Kermit spoofing asynchronous protocol.

:K2

Enables UUCP spoofing asynchronous protocol.
Enables the Kermit or UUCP spoofing asynchronous protocol (emulation). The same
protocol (Kermit or UUCP) must be enabled on both the originating and answering
modems. You can use the Kermit and UUCP protocols only during an MNP reliable
connection, with or without data compression. The protocols are not available during
direct, normal, or synchronous operation.
The Read Online Status command displays KERMIT when the modem establishes a
Kermit connection and UUCP for a UUCP connection.
See also the :Q command.

\Kn Break Control
Where n is a number between 0 and 5 indicating the type of Break the modem transmits
(Default is 5).
Determines the type of Break the modem transmits when a Break enters the modem.
The following tables list the different effects of the n value when the modem receives
or transmits the Break. The modem can buffer up to four Breaks on both the modem
port and the serial port.

NOTE
In the reliable link connect state, the sender’s Break control setting determines
how the receiver handles the Break.

AT Commands F-29

AT Commands
The following table illustrates the \Kn command.
Command

Local DTE
sends Break
during reliable
or normal
connection

Local DTE
sends \Bn ;
local modem
in command
mode, during
reliable or
normal
connection

Local modem
sends Break
during Direct
connection

Remote
modem
sends
Break
during
normal
connection

\K0

Enter command
state; no Break to
remote system1

Empty data
buffers; send
Break to remote
system

Send Break to
remote system; set
modem to
command state

Empty data
buffers; send
Break to serial
port

\K1

Empty data
buffers; send Break
to remote system

Same as \K0

Send Break to
remote system

Same as \K0

\K2

Same as \K0

Immediately
send Break to
remote system

Same as \K0

Immediately
send Break to
serial port

\K3

Immediately send
Break to remote
system

Same as \K2

Same as \K1

Same as \K2

\K4

Same as \K0

Send Break to
remote system in
sequence with
any transmit data
being buffered

Same as \K0

Send Break to
serial port in
sequence with
receive data
being buffered

Same as \K4
Same as \K1
Same as \K4
Send Break to
remote system in
sequence with
transmit data
1.Forces the modem to command state. To transmit a Break and enter connect state, issue
AT\BO. (See the \B command description for details.)

\K5

F-30 AT Commands

AT Commands

$Ln Logon Sequence
Edit logon sequence n, where n = 1-9.
Allows you to edit logon sequences to be used during normal or reliable connections
in either originate mode or auto-answer mode. If a Security Database password has
been set, you must enter the correct password before you can edit a logon sequence.
(See also the $P command.) If no password has been set, anyone can edit the logon
sequence.

%Ln Speed Matching
%L0

Provides partial speed matching.

%L1

Enables speed matching.

%L2

Disables speed matching.

%L3

Enables ITU-T Automode.
Determines whether the modem uses speed matching to establish a connection.
With %L3 set, modem operation complies with the proposed annex to the ITU-T V.32
specification for automoding when interworking with V.22bis and V.22 modems. :T13
defines how long the answering modem tries to establish an ITU-T automode
connection. %L3 must be set in order for register :T13 to take effect.
The following charts indicate the connections that the modem can establish when %L1
or %L3 is set.
Modem

Setting

Answering

Modem

Mode Setting
on
Originating
Modem

V.22[b]

V.22[a]

V.22bis

V.32

V.32bis

V.34

V.34 (1440028800)

---

V.22[a]

V.22bis

V.32

V.32bis

V.34

V.32bis (480014400)

---

V.22[a]

V.22bis

V.32

V.32bis

V.32 (48009600)

---

V.22[a]

V.22bis

V.32

V.22bis (2400)

---

V.22[a]

V.22bis

V.22[a] (1200)

---

V.22[a]

V.22[b] (600)

V.22[b]

---

AT Commands F-31

AT Commands
Modem

Setting

Answering

Modem

Mode Setting
on
Originating
Modem

V.22[b]

V.22[a]

V.22bis

V.32

V.32bis

V.34

V.23[a] (xmt 75)

---

V.23[b]

V.23[b] (xmt
1200)

---

V.23[c] (halfduplex)

---

V.23[c]

V.21(75-300)

---

V.21

Bell212A (1200)

---

V.22[a]

Bell103 (300)

---

Bell103

Modem

Setting

Answering

Modem

Mode Setting
on
Originating
Modem

V.23[a]

V.23[b]

V.23[c]

V.21

Bell212A

Bell103

V.34 (1440028800)

---

V.22[a]

---

V.32bis (480014400)

---

V.22[a]

---

V.32 (48009600)

---

V.22[a]

---

V.22bis (2400)

---

V.22[a]

---

V.22[a] (1200)

---

V.22[a]

---

V.22[b] (600)

---

V.23[a] (xmt 75)

---

V.23[b]

---

V.23[b] (xmt
1200)

V.23[a]

---

V.23[c] (halfduplex)

---

V.23[c]

---

F-32 AT Commands

---

AT Commands
Modem

Setting

Answering

Modem

Mode Setting
on
Originating
Modem

V.23[a]

V.23[b]

V.23[c]

V.21

Bell212A

Bell103

V.21(75-300)

---

V.21

---

Bell212A (1200)

---

Bell212A

Bell103 (300)

---

Bell103

AT Commands F-33

AT Commands
To restrict the possible connections that can result, either %L0 or %L2 can be set on either the
originating or answering modem. The following table shows the possible connection speeds if
%L0- is set:
Modem Speed

Possible Connection Speed

300

600

1200

2400

1200, 2400

4800

7200

4800, 7200

9600

4800, 7200, 9600

12000

4800, 7200, 9600, 12000

14400

4800, 7200, 9600, 12000, 14400

14400V

14400

16800

14400, 16800

19200

14400, 16800, 19200

21600

14400, 16800, 19200, 21600

24000

14400, 16800, 19200, 21600, 24000

26400

14400, 16800, 19200, 21600, 24000, 26400

28800

14400, 16800, 19200, 21600, 24000, 26400,
28800

NOTE
If %L2- is set, the modem speed and the connection speed are identical.

F-34 AT Commands

AT Commands

$Mn Connection Security Password Control
$M0

The originating modem sends the Connection Security password; the answering
modem does not verify the Connection Security password.

$M1

$M2

The originating modem sends the Connection Security password; the answering
modem verifies the Connection Security password for all connections. If the
originator’s password does not match one of the answerer’s passwords, the answerer
uses auto-logon string 5 to prompt the remote user (up to three times) for the
Connection Security password. If the Auto-Logon sequence fails, the connection fails.

)Mn Power Level Adjustment for Cellular Telephone Connections
)M0

For central site modems: Auto-adjustment (adjusts power level if remote modem is set
to )M1 ). Use for MNP Class 10 modems that will connect to both cellular telephone
and non-cellular telephone site modems.

)M1

For cell-side cellular modems: Forces adjustment of power level.
Adjusts the power levels during link negotiation for reliable connections to
accommodate signaling requirements of cellular telephone equipment.

*M Modify Remote Access Level
Initiates a request to move up from a Level 0 remote access session to a Level 1 remote
access session. With security enabled and a Level 1 password set, the modem prompts
for a valid password up to three times before granting Level 1 access. With security
disabled or enabled but a Level 1 password not set, the modem grants Level 1 access
on request without further prompting.

-Mn MNP Class Connection Messages
-M0

Disables MNP Class connection messages.

-M1

Enables MNP Class connection messages.
Determines whether MNP Class connection messages are displayed. The -M1 setting
overrides the \V command setting for long form connection result codes and the W
command for serial port connect messages.
When -M1 is set and an MNP connection established, the connect message is
CONNECT MNPn/x, where n equals the MNP Class (from 1 to 10) and x equals the
type of data compression used (V.42bis or MNP Class 5). If )M1 is set, the message is
CONNECT MNPn/y/x, where y equals CELLULAR. If the modems do not negotiate
compression, the message is CONNECT MNPn.

AT Commands F-35

AT Commands
During LAPM V.42bis connections when -M1 is set, the connection message is
CONNECT LAPM/V42BIS. During LAPM connections with no compression active,
the message is CONNECT LAPM.
When -M1 is set, the message during normal and direct connections is CONNECT.
The modem ignores this command with short-form result codes enabled by V0.
Setting X0 will also override the -M setting by displaying only CONNECT.

@Mn Select Transmit Level (Only for Cellular Connections)
@M0

Use an initial transmit level of -26 dBm.

@M1

Use an initial transmit level of -30 dBm.

@M2

Use an initial transmit level of -10 dBm.

@M10

Use an initial transmit level of -10 dBm.

@M35

Use an initial transmit level of -35 dBm.
Selects the initial transmition level for your connection. You can set levels from -10
dBm through -35 dBm. The command is structured as follows:
From @M10 through @M35, the level set is the variable expressed as -dBm. For
example, @M18 sets -18 dBm.
We recommend that you set @M18 when making cell-side cellular calls. You may
need to adjust this level, depending on your cellular equipment.

\Nn Operating Mode
\N0

Sets normal mode.

\N1

Sets direct mode.

\N2

Sets reliable mode.

\N3

Sets auto-reliable mode.

\N4

Sets LAPM reliable mode.

\N5

Sets LAPM reliable mode with fallback to normal mode.

\N6

Sets LAPM reliable mode with fallback to MNP reliable mode.
NOTE
You can use dial modifiers to set the operating mode for a single call. See the D
command description for details.

F-36 AT Commands

AT Commands
Normal mode (\N0) can communicate with nearly any modem. Error correction does
not take place in normal mode.
Direct mode (\N1) does not buffer data and ignores flow control. Also, in connect state,
the serial port always adjusts to the speed of the connection, regardless of the setting
of \Jn. Error correction does not occur.

NOTE
Setting \J0 disables the escape code sequence in direct mode.

Reliable mode (\N2) uses the MNP reliable link to provide error detection and
automatic retransmission of data if an error occurs. This provides for error-free
communications between your system and another that supports the MNP reliable link.
When \N2 is in effect, the modem disconnects if it fails to establish an MNP reliable
link immediately after making a connection.
During an MNP reliable link, both modems should use flow control on the serial port.
When the modem detects a transmission error, it holds data in a buffer attempting to
retransmit.

NOTE
You may not want to use certain other protocols, such as HP Block Mode, with
MNP. Such protocols have particular timing requirements that can interfere with
MNP’s effectiveness.

Auto-reliable mode (\N3) allows the modem to communicate with remote systems that
support the MNP or LAPM reliable link and with systems that do not support the
reliable link. In auto-reliable mode, the answering modem looks for incoming MNP or
LAPM protocol characters from the remote modem. If it detects them within
approximately three seconds, it tries to establish a reliable link connection.
When the modem is set to auto-answer in auto-reliable mode, you can shorten this
three-second period by using the %A command with the \C2 command.

AT Commands F-37

AT Commands

NOTE
If both modems are set to auto-reliable mode, a normal connection or no
connection could result due to noise on the telephone line.

LAPM reliable mode (\N4) uses the LAPM reliable link to provide error detection and
automatic retransmission of data if an error occurs. This ensures that communications
between your system and the remote system are error-free. The remote system must
also be equipped to handle a LAPM reliable link. The modem attempts to establish an
LAPM reliable link immediately after making a connection. If the attempt fails, the
modem disconnects.
LAPM reliable mode with fallback to normal mode (\N5) attempts to establish an
LAPM reliable connection. If the LAPM connection attempt fails, the modem falls
back to a normal connection.
LAPM reliable mode with fallback to MNP reliable mode (\N6) attempts to establish
an LAPM reliable connection. If the LAPM connection attempt fails, the modem then
tries to establish an MNP reliable connection.
The following chart indicates the type of connections, depending on the operating
mode. NC indicates No Connection. Where more than one operating mode is in a
column, the first mode is for the originating modem and the second mode is for the
answering modem.

Note for MNP Extended Services:
In the following table, you can use MNP Extended Services for V.42 connections
where LAPM appears if both modems are set with -K1 or -K2

F-38 AT Commands

AT Commands
:
Originating

Modem

Answering
Modem

\N0

\N1

\N2

\N3

\N4

\N5

\N6

\N0

normal

direct/normal

normal

\N1

normal/
direct

direct

NC/

normal/
direct

\N2

MNP

\N3

normal

direct/normal

MNP

LAPM

\N4

LAPM

\N5

normal

direct/normal

LAPM

\N6

MNP

LAPM

NOTE
The modem does not support LAPM error correction for Bell 103, V.21, and V.23
connections.

$N List Connection Security Passwords
Displays the Connection Security Password database. (See %I and $P for details on
setting these passwords.)

On Enter Connect State
O0

Enters connect state.

Begins an equalizer retrain sequence when operating at 2400 bps or higher and then
returns to connect state.
Type ATO1 to reduce errors due to loss of equalization when excessive bit error rates
are present.

AT Commands F-39

AT Commands

NOTE
Issuing ATO1 during a remote access session returns ERROR.

$On Originate/Answer Control
$O0

Determines whether originate or answer mode as set by the O/A button.

$O1

Disables O/A button and forces originate mode.

$O2

Disables O/A button and forces answer mode.
The modem reads the O/A button to determine whether to operate in originate or
answer mode when:
•

you press the T/D button

•

you type AT$T2

•

it is in leased-line mode

NOTE
The modem saves the $O value when you set it. You do not have to enter an &W
or *W to save it.

%On V.23 Equalizer Control;
%O0

Disables equalizers in V.23 half-duplex mode.

%O1

Enables equalizers in V.23 half-duplex mode.
Determines whether equalizers are set in V.23 half-duplex mode. To avoid
transmission errors during V.23 half-duplex connections, equalizer settings must be
the same on both modems.

F-40 AT Commands

AT Commands

-On Serial Port Parity
-O0

7 data bits, odd parity.

-O1

7 data bits, even parity.

-O2

7 data bits, mark parity.

-O3

7 data bits, space parity.

-O4

8 data bits, no parity.

-O5

8 data bits, odd parity.

-O6

8 data bits, even parity.

-O7

8 data bits, mark parity.
Allows you to change the serial port parity setting that is automatically set by the AT
sequence.
You can also use the -O command to change the serial port parity while connected to
a remote device. Use this command when the local device supports XON/XOFF flow
control and detects parity. This command ensures that all XON and XOFF characters
generated by the modem have the correct parity.
You cannot change the modem port parity during a connection. When parity is
required for a connection and is different than the parity set by the AT sequence, the
parity must be set at the same time the dial command is issued and issued on the same
command line.

Example

AT-O4D12345

NOTES
•

The AT sequence cannot be used to match 8 bit data with mark parity. Eight data
bits plus mark parity can only be set by the AT-O command. If -O7 is not set, the
modem defaults to 8 data bits, no parity.

•

The AT sequence cannot be used to match space parity; no parity is set instead.
You must issue AT-O3 to set space parity.

P Pulse Dial
Changes the current dialing mode to pulse. Tone dialing is the default.

$P Security Database Password
Allows you to change the password needed to edit the auto-logon sequences, Dial
Access and auto-logon commands, and Connection Security passwords. The default is
that no password has been set.
AT Commands F-41

AT Commands
The following prompts appear when you issue the $P command:
Prompt:

Response:

OLD PASSWORD:

Type the existing password for verification.
Press Enter. If a password has not been set, just
press Enter.

NEW PASSWORD:

Type a new password and press Enter.

NEW PASSWORD:

For verification, type the new password and
press Enter again.

Passwords must contain exactly five alphanumeric characters. Upper case or lower
case and parity are ignored. You must type the old password correctly in order to enter
a new password. You must type the new password the same way both times for it to
take effect. Periods are echoed as the password is entered.

NOTES
•

The password becomes valid 2 minutes after the last logon or Connection Security
password was entered.

•

If you forget your password, you can just press at the OLD PASSWORD: prompt.

$P Security Database Password (V.25bis Synchronous Mode)
AT$Pooooo;nnnnn; Where ooooo equals the old password and nnnnn equals the new password
Sets a new password or changes an existing password. Issue this command at least
once to enable the modem’s connection security operation for the first time. If a
password has never been set or you erase it, there is no password connection security
in effect.
You must type the two ; (semicolons) where indicated. Passwords must contain exactly
five alphanumeric characters. The modem ignores upper case or lower case and parity.
You must type the old password correctly in order to enter a new password.

NOTE
If you forget your password, you can just press at the OLD PASSWORD: prompt.

F-42 AT Commands

AT Commands

&Pn Dial Pulse Ratio
&P0

Make = 39%, Break = 61%.

&P1

Make = 33%, Break = 67%.
Controls the ratio of the off-hook (make) to on-hook (break) interval that the modem
uses for pulse dialing.

*Pn Remote Access Passwords
*P0

Sets Level 0 remote access password.

*P1

Sets Level 1 remote access password.
Allows you to set a password used to establish a remote access session.

NOTE
Important: Set all passwords before enabling security.

The *P command must be the last command on the command line. Both Level 0 and
Level 1 passwords are set to null at the factory.
The following prompts appear when you issue this command:
Prompt:

Response:

OLD PASSWORD:

Type the existing password for verification.
Press Enter. If a password has not been set, just
press Enter.

NEW PASSWORD:

Type a new password and press Enter.

NEW PASSWORD:

For verification, type the new password and
press Enter again

Passwords must contain exactly five alphanumeric characters. The modem ignores
upper case or lower case and parity. You must type the old password correctly in order
to enter a new password. You must type the new password the same way both times
for it to take effect. Periods echo on the terminal as you enter the passwords.

AT Commands F-43

AT Commands

-Pn Check Parity
-P0

Ignores parity of special characters.

-P1

Processes special characters only if their parity matches that of the serial port.

-P2

Processes special characters only if their parity matches that of the serial port.
Recognizes modem port flow-control characters, however, regardless of whether their
parity matches the serial port parity.
Controls checking of parity for XON and XOFF characters, the escape code sequence,
and HP ACK characters. In command state, the modem sends all command echoes and
command responses to the computer with parity that matches the serial port’s.
When -P0 or -P1 is set, all received data is passed through to the computer at 8 data
bits, no parity.
When -P2 is set, all received data is passed through to the computer with parity
corrected to match the serial port parity.

NOTE
The -P command is used only for 10-bit data; the modem ignores -Pn when it is
set for 11-bit data.

\Pn <dial string> Write a Stored Telephone Number
Where n is the telephone directory position from 01 to 40 and <dial string> is a string
of up to 39 characters. Valid dial string characters are: 0-9, dial modifiers, and for tone
dialing A, B, C, D, #, and*. Dial strings longer than 39 characters return an error
message. The modem ignores invalid characters.
Stores a telephone number in the modem’s telephone directory.

Qn Quiet
Q0

Enables output of result codes.

Disables output of result codes.

Disables answer mode result codes only.
Determines whether the modem sends result codes and status codes (OK, BUSY,
RING, etcetera) to your computer.

F-44 AT Commands

AT Commands

*Q Recover Remote Access Configuration
Discards configuration changes you made during a Level 1 remote-access session but
did not save with an *U. The *Q or *U commands do not affect commands that
configure remote-access operation or telephone numbers that you added or changed.

NOTE
When you modify stored telephone numbers during a remote-access session, your
changes take effect immediately.

-Qn Fallback Modulation Speeds
-Q0

Disables fallback from a V.32bis or V.32 MNP reliable connection to an MNP reliable
2400 or 1200 bps connection.

-Q1

Enables fallback from a V.32bis or V.32 MNP reliable connection to an MNP reliable
2400 bps connection.

-Q2

Enables fallback from a V.32bis or V.32 MNP reliable connection to an MNP reliable
2400 or 1200 bps connection.
Controls whether the modem can fall back from a V.32bis or V.32 MNP reliable
connection to a V.22bis MNP reliable connection at 2400 bps or a V.22 MNP reliable
connection at 1200 bps. Fallback may occur when poor telephone lines cause excessive
MNP retransmissions.
Fallback from a V.32bis or V.32 MNP reliable connection to a 4800 bps V.32bis or
V.32 MNP reliable connection is always enabled, regardless of the -Q setting. The
modem always uses the V.22 standard when it falls back from a V.32bis or V.32 MNP
reliable connection to a 1200 bps MNP reliable connection, regardless of the B setting.

:Qn Kermit Mark Character
Where n is an integer from 0 to 31 indicating an ASCII character (Default is 1)
Defines the Kermit mark character the modem uses with the Kermit spoofing
asynchronous protocol enabled. This character must match the computer’s Kermit
mark character. Most computers use the default Kermit mark character (1). Both the
originating and answering modems must use the same Kermit mark character. See also
the :K command.

AT Commands F-45

AT Commands

\Qn Serial Port Flow Control
\Q0

Disables flow control.

\Q1

Enables bi-directional XON/XOFF flow control.

\Q2

Enables unidirectional hardware flow control; the modem uses CTS to control the
terminal.

\Q3

Enables bi-directional hardware flow control.

\Q4

Enables unidirectional XON/XOFF flow control.

\Q5

Keeps CTS Off until connection for unidirectional hardware flow control

\Q6

Keeps CTS Off until connection for bi-directional hardware flow control; ignores RTS
until connection.
Sets the type of flow control used on the serial port. If the serial port speed is faster
than the modem port speed, data from your computer enters the modem faster than it
leaves. The modem holds characters in a buffer and sends them out at the slower
modem port bps rate. When the buffer is full, flow control instructs your computer to
stop transmitting data to the modem; the modem continues to send out the characters
and empty the buffer. When there is room in the buffer, flow control instructs your
computer to resume transmitting data to the modem.
For reliable connections, retransmissions can reduce the effective modem port speed.
If this occurs, flow control prevents buffer overflow.
During direct mode connections, the modem does not use flow control and ignores the
\Q setting.

NOTE
Hardware flow control overrides the &C and \D settings for CTS operation.

\Q1: Enables bi-directional XON/XOFF flow control. Sending an XOFF character
stops data transmission; sending an XON character restarts it. The modem generates
XON and XOFF characters at the same parity as on the serial port. The serial port
responds to XON and XOFF characters from the local computer in the same way.
\Q2: Enables unidirectional hardware flow control. The modem turns CTS Off to
signal the local computer to stop transmitting data, and turns CTS On to signal the local
computer to resume transmitting data.
\Q3: Sets bi-directional hardware flow control using the CTS and RTS signals. The
modem uses the CTS signal to start and stop data transmission from the local
computer. When RTS is Off, the modem stops transmitting data to the local computer.
When RTS is On the modem resumes sending data.

F-46 AT Commands

AT Commands
\Q4: Enables unidirectional XON/XOFF flow control. The modem serial port
generates, but does not respond to, XON/XOFF flow control characters. This setting
allows for computers to transmit data that has XON and XOFF data characters. The
computer can still be set to respond to XON/XOFF flow control characters sent to it
from the modem during serial port flow control.
\Q5: Enables unidirectional hardware flow control the same as \Q2, but also keeps CTS
Off until a connection is established.
\Q6: Enables bi-directional hardware flow control the same as \Q3, but also keeps CTS
Off until a connection is established and ignores RTS while not connected.

%Rn Read All Registers
%R0

Displays the contents of all S-registers in decimal and hexadecimal integers in tabular
format.

%R1

Displays the contents of all :Tn registers in decimal and hexadecimal integers in
tabular format.

&Rn RTS/CTS Options
&R0

CTS tracks RTS in synchronous mode.

&R1

CTS ignores RTS in synchronous mode.

&R2

ITU-T V.13 emulates half-duplex over a full duplex line.
Use either &R0 or &R2 to simulate half-duplex synchronous operation. When &R0 is
set, after the register S26 time delay, CTS follows the state of RTS sent from the
computer. When &R1 is set, CTS remains On for the duration of the connection.

NOTES
•

The modem ignores &R during asynchronous connections.

•

Refer to the register :T15 description for details on RTS/CTS.

AT Commands F-47

AT Commands

*Rn Enable Remote Access Security
*R0

Disables remote access security.

*R1

Enables remote access security.
Control remote access security. With remote access security on and passwords set,
password entry determines whether the modem grants Level 0 or Level 1 access at the
start of a remote access session. With remote access security off, the modem does not
require passwords and grants Level 0 access.

NOTES
•

Remote access is available only during a normal connection or during an MNP
reliable connection without data compression.

•

You must disable remote access security on the local modem, not during a remote
access session.

•

Set all passwords before you enable remote access security. Otherwise, an error
message appears.

:Rn Simulate Ring
:R0

Modem does not simulate ring or act on pulse leads.

:R1

If DTR is low and &D1, &D2, or &D3 is set, the modem simulates ring until DTR is
raised. If DTR is high or if &D0 is set, the modem does not simulate ring and connects
immediately. If the modem simulates a ring and DTR is not raised after 30 seconds,
the modem disconnects.

:R2

Does not simulate ring, but acts on pulse leads.
During MI/MIC operation, controls whether the modem simulates ring according to
the &D setting, as noted above.

\Rn Serial Port Ring Indicator
\R0

Keeps the Ring Indicator signal On for the duration of the telephone call.

\R1

Turns Off the Ring Indicator signal after the telephone call is answered.
Controls the Ring Indicator (RI) signal. When an incoming call comes in, the RI signal
tracks the ring signal on the telephone line.

Sn? Read Configuration Register
Where n is an integer. Displays the contents in decimal form of the selected S-register.

F-48 AT Commands

AT Commands

%Sn Display Switch Settings
%S0

Displays Bank 1 switch settings.

%S1

Displays Bank 2 switch settings.

%S2

Displays internal switch settings.

&Sn DSR Options
&S0

DSR is always on.

&S1

DSR complies with ITU-T recommendations.
Controls the Data Set Ready (DSR) signal on the serial port.

NOTE
&S0 is equivalent to setting \D0. &S1 is equivalent to setting \D3.

*Sn Remote Access Attention Character
Where n is an integer between 0 and 126 indicating an ASCII character
[Default is 42, *].
Defines the attention character to request a remote access session. To request a remote
access session using this character, establish a connection and type the attention
character four times in succession (do not type a carriage return). The *A command
sends this sequence automatically.
In normal mode, register S12 sets the guard time that precedes and follows the
attention character sequence. It should be set to the same value on both the originating
and answering modems. Reliable mode uses its own timing and the modem ignores
register S12. During reliable connections, allow a short pause between typing each
attention character, or type AT*A instead.

NOTE
Remote access is available only during a normal connection or during an MNP
reliable connection without data compression.

AT Commands F-49

AT Commands

\S Read Online Status
Displays a list of modem commands and their current settings. This command also
displays the active connection type, as well as the elapsed connect time and the
telephone number most recently dialed.
The \S command displays several screens. Press any key to move to the next screen.
To cancel the display, type the line-delete character – or send a Break.

T Tone Dial
Changes the current dialing mode to tone. This is the modem’s default.

&Tn Test and Diagnostics Commands
&T0

Ends test in progress.

&T1

Local analog loopback.

&T3

Local digital loopback.

&T4

Respond to remote digital loopback.

&T5

Do not respond to remote digital loopback.

&T6

Remote digital loopback.

&T7

Remote digital loopback with self-test.

&T8

Local analog loopback with self-test.
NOTE
The modem does not support &Tn commands for Bell 103, V.13, V.21, and V.23
modes.

&T0: Ends a test in progress without terminating a connection, and returns the local
and remote modems to normal operation. If a self-test is in progress, &T0 reports any
errors. The &T0 command must be the last command on a command line.
&T1: The modem should display the characters on your screen exactly as you type
them. The modem must be in normal or direct mode and set to 1200 bps or higher.
&T3: Allows a remote modem that does not support the ITU-T V.54 standard to
perform a Remote Digital Loopback test with your modem. The modem must connect
in normal or direct mode and be set to 1200 bps or higher.
&T4: Allows the modem to respond to a remote caller's request to enter Remote
Digital Loopback mode.
&T5: Prevents the modem from responding to a Remote Digital Loopback request.
F-50 AT Commands

AT Commands
&T6: Instructs the remote modem to initiate a Remote Digital Loopback test. This
command is available only when the modem is connected in normal or direct mode and
set to 1200 bps or higher.
&T7: Instructs the remote modem to enter a Remote Digital Loopback with Self-Test.
Upon completion of the test, the modem reports errors to the local device. This
command is available only when the modem connects in normal or direct mode and is
set to 1200 bps or higher.
&T8: The modem sends itself the ITU-T V.54 test pattern and verifies these
characters. Upon completion of the test, the modem reports errors to the local device.
This command is available only when the modem is in normal or direct mode and set
to 1200 bps or higher.

:Tn? Read Configuration Register
Where n is an integer indicating a :T-register. Displays the contents in decimal form of
the selected :T-register.

\Tn Inactivity Timer i.Inactivity timer;
Where n is an integer between 0 and 90 specifying minutes (Default is 0).
Specifies the number of minutes the modem waits for data before automatically
hanging up. \T0 (default) disables the inactivity timer. The inactivity timer is only
available during normal and reliable link connections; the modem ignores it in direct
or synchronous mode.

AT Commands F-51

AT Commands

%Un Clear Serial Port Speed
%U0

When issued, allows the current serial port speed (19200 bps or lower) to change to
another speed.

%U1

Always keeps the current serial port speed. To change the serial port speed, you must
enter %U1 each time you change the serial port speed.

%U2

Allows the current serial port speed to change from any speed.
NOTES
•

You do not need to issue %U when bps rate adjust causes the serial port speed to
change during a connection.

•

You need to issue AT%U0 when changing from 11-bit characters to 10-bit
characters, and from 10-bit to 11-bit.

•

When the serial port speed is set to 38400 bps or higher, it cannot be changed until
you enter an AT%U command or reset the modem.

*U Update Remote Access Configuration
Saves configuration changes made during a Level 1 remote access session. At
disconnect, the modem loses configuration changes you made during a Level 1 session
if you do not enter *U, and it restores the original configuration. This command does
not affect remote access configuration commands. Stored telephone number changes
take effect immediately during a remote access session.

NOTE
To save the configuration even after the modem is reset, also issue either &W or
*W.

F-52 AT Commands

AT Commands

:Un DCD Time Delay
Where n is an integer from 0 to 255 representing periods of 12.5 milliseconds. Default
is 0. During MI/MIC operation, sets how long the modem waits before turning on DCD
(carrier detect).

NOTES
•

The :U command takes effect when :R1 is set. If the DCD signal is already On
before the connection, the modem ignores the :U command.

•

The modem supports this command in Dial Access Security. :R does not need to
be set.

@Un Minimum Connection Speed
Where n = 300, 600, 1200, 2400, 4800, 7200, 9600, 12000, 14400, V14400, 16800,
19200, 21600, 24000, 26400, 28800, 33600 bps.
Sets the minimum modem port speed for connections. For example, if you want your
modem to only make connections greater than or equal to 4800 bps, set AT@U4800.
The modem will only make connections at 4800 bps or higher.

Vn Result Code Form
V0

Sends short-form result codes.

Sends long-form result codes.
Selects whether the modem sends long-form (words) or short-form (numeric) result
codes to your computer. The format of the connection result codes is dependent upon
the \V, W, and -M commands.

$Vn Logon View Mode
$V0

Disables pass through of data during the logon sequence.

$V1

Enables pass through of data during the logon sequence.
Determines whether data passes through from the remote system to the local computer
during the logon sequence. With view mode disabled ($V0), the modem does not pass
through any data and delays the connect message until the logon sequence is complete.
With view mode enabled ($V1), the connect message displays and then data pass
through during the logon sequence.

%V Display Modem Firmware Version
Displays the modem firmware main code version.
AT Commands F-53

AT Commands

-V Split Serial Port Speed with Multi-Protocol Auto-Answer
-V0

Enables V.23 split serial port speed connections within the multi-protocol auto-answer
feature.

-V1

Disables V.23 split serial port speed connections within the multi-protocol autoanswer feature.
Determines whether the serial port uses split transmit and receive speed operation
when using the multi-protocol auto-answer feature. %F0 must also be set.

:Vn CTS Time Delay
Where n is an integer from 0 to 255 representing periods of 12.5 milliseconds. Default
is 0. During MI/MIC operation, sets how long the modem waits before turning on CTS
(Clear to Send).

NOTES
•

The :V command takes effect when :R1 is set. If the CTS signal is already On
before the connection, the :V command is ignored.

•

The modem supports this command in Dial Access Security. :R does not need to
be set.

\Vn Error Correction Result Code Form
\V0

Uses standard long-form result codes: CONNECT <speed>.

\V1

Adds /REL to long-form error correction result codes: CONNECT <speed>/REL.

\V2

Displays long-form error correction protocol result codes: CONNECT <speed>/RELMNP or CONNECT <speed>/REL-LAPM or CONNECT <speed>/RELCELLULAR.

\V3

Adds /REL to long form error correction result codes: CONNECT <speed>/REL.
Displays Hayes-compatible short-form (numeric) result codes.

\V4

Displays long-form error correction protocol result codes: CONNECT <speed>/RELMNP or CONNECT <speed>/REL-LAPM or CONNECT <speed>/RELCELLULAR.
Determines whether result codes indicate that a reliable link connection is in effect.
The W setting determines the contents of the <speed> field. Setting -M1 changes the
format of the long-form connect result codes.
Even for a reliable connection, use \V0 when your data communications software does
not expect to see a reliable link result code.

F-54 AT Commands

AT Commands
Use \V1, \V2, \V3 or \V4 when your software supports error correction result codes.
Use V0\V3 if your communications software requires Hayes-compatible connection
result codes. Note that when V1 is set to select long-form result codes \V3 is equivalent
to \V1.
Use \V3 or \V4 when you want to see the actual connect speed.

NOTE
When either \V1 or \V2 is set, the message CONNECT 9600/REL displays during
4800, 7200, and 12000 bps reliable connections. When either \V3 or \V4 is set, the
actual modem bps rate displays for 4800, 7200, and 12000 bps reliable
connections.

^V Display Bootstrap Revision
Requests modem to display its current flash memory bootstrap revision.
NOTE
This is part of the memory update operations.

Wn Connection Speed Reporting
W0

Displays serial port connect messages.

Displays modem port connect messages.
When W0 or W1 is set, the speeds reported in connect messages indicate the serial port
speed.
When W2 is set, the speeds reported in connect messages indicate the modem port
speed.
When X0 is also set, CONNECT displays, regardless of the W setting.

AT Commands F-55

AT Commands

%Wn Pulse Digit Command
%W0

n pulse digits dialed for each number.

%W1

n+1 pulse digits dialed for each number.

%W2

10-n pulse digits dialed for each number.
For pulse dialing, determines whether the modem dials each number in a dial string n
pulses, n+1 pulses, or 10-n pulses. For example, when %W0 is in effect, it dials 6 with
6 pulses. However, with %W1, it dials 6 with 7 pulses; with %W2, it dials 6 with 4
pulses.

NOTE
With %W0 or %W2 set, the modem dials digit 0 with 10 pulses. When %W1 is
set, digit 0 is dialed with 1 pulse.

&Wn Store Current Configuration
Stores current user profile n (where n = 0 to 3) (Default is 0).
Stores the active commands and certain S-registers. You store telephone numbers
independently with the \Pn and &Zn commands. The &W command stores the serial
port speed and parity and the modem port speed that are in effect when you enter &W.
The &W command does not store the following restricted S-registers:
S
2

S
3

S
4

S
5

S
6

S
7

S
8

S
9

S
1
0

S
1
1

S
1
2

The modem saves the following command settings when you enter them. You do not
need to also enter &W or *W.

F-56 AT Commands

AT Commands
The following table lists the remote access settings:
Command

Description

Enable Remote Access

Modem Identifier

Remote Access Password

Enable Remote Access Security

Remote Access Attention Character

The following table lists the auto-logon settings:
Command

Description

Edit Dial Access Security Database

Logon Sequence

Security Database Password

The following table lists other commands:
Command

Description

Edit Connection Security Password

Disable Switch Banks

Originate/Answer Control

T/D Button Control

Designate Default User Profile

See also the *W and Z commands.

AT Commands F-57

AT Commands

*Wn Store Complete Configuration
Stores complete user profile n (where n = 0 to 3) (Default is 0).
Stores all active commands and registers as well as the restricted S-registers not stored
with &W. (See the &W command description.)
Save telephone numbers independently with the \Pn and &Zn= commands. The *W
command saves the serial port speed and parity and the modem port speed in effect
when you enter *W .
See also the &W, &Y, and Z commands.

NOTES
•

The &W and *W commands share the same stored configuration area. Issue one
of these commands to override the other stored settings.

•

The &W command setting stores default settings for the restricted S-registers. If
&W is issued after issuing *W, the default settings for the restricted S-registers
are stored. If you change the setting of one of the restricted S-registers and want
to save it, use the *W command instead of the &W command.

Xn Extended Result Codes
X0

Modem ignores dial tone and busy signals. Displays CONNECT when it establishes a
connection. Smartmodem 300 compatible.

Modem ignores dial tone and busy signals. Sends a connect result code including bps
rate when it establishes a connection.

Modem ignores busy signals. Displays NO DIALTONE if it does not detect one within
5 seconds of dialing. Sends a connect result code reflecting bps rate when it establishes
a connection.

Modem ignores dial tone. Displays BUSY if it detects a busy signal. Sends a connect
result code reflecting bps rate when it establishes a connection.

Displays NO DIALTONE if it does not detect one within 5 seconds of dialing.
Displays BUSY if it detects a busy signal. Sends a connect result code reflecting bps
rate when it establishes a connection.
Determines whether the modem responds to dial tone and busy signals, and what kind
of CONNECT result codes are displayed. Result codes are further controlled by the Vn
command. Result codes indicate MNP reliable mode only when either \V1, \V2, \V3,
\V4, or -M1 is set. When the modem ignores dial tone, it waits for the register S6 time
delay to expire and then dials regardless of whether a dial tone is present.

F-58 AT Commands

AT Commands

NOTE
The “W” dial modifier causes the modem to wait for dial tone regardless of the X
setting.

*X Exit Remote Access
Moves remote access down one level. When you enter an *X command during a Level
1 remote access session, access moves down to Level 0. When you enter it during a
Level 0 session, the remote access session terminates and the originating modem
returns to connect state.

-X Display Stored Switch Settings
Displays the current stored configuration switch settings.

:Xn DSR Time Delay
Where n is an integer from 0 to 255 representing periods of 12.5 milliseconds. Default
is 0. During MI/MIC operation, sets how long the modem waits before turning on DSR
(Data Set Ready).
NOTES
•

The :X command takes effect when :R1 is set. If the DSR signal is already On
before the connection, the :X command is ignored.

•

The modem supports this command in Dial Access Security. :R does not need to
be set.

\Xn XON/XOFF Pass-Through
\X0

Processes XON/XOFF flow control characters.

\X1

Processes XON/XOFF flow control characters and passes them through to the local or
remote system so that the local or remote device also processes the XON and XOFF
characters.
Determines whether XON/XOFF flow control characters pass to the remote or local
modem. With XON/XOFF flow control enabled on the serial port (\Q1) and pass
through enabled (\X1), the modem also transmits to the remote device any XON and
XOFF characters sent to the serial port from the local device.

AT Commands F-59

AT Commands

NOTE
With \X0 set and XON/XOFF flow control enabled, local devices such as
computers or printers may send XON and XOFF characters to the modem serial
port. If the modem is already controlling the flow of data to the remote system,
local flow control characters will not interfere with the connection. However, if
\X1 is set, local flow control characters also pass through to the remote system.
These flow control characters are intended for the local system and may turn on
the flow of data from the remote system before the modem is ready to receive
more data, resulting in a loss of data.

Yn Long Space Disconnect
Y0

Disables long space disconnect on receipt of H, T/D toggle, or DTR drop if &D2 or
&D3 is set.

Enables long space disconnect on receipt of H, T/D toggle, or DTR drop if &D2 or
&D3 is set.
Sends a Break up to 4 seconds before disconnecting in response to an H command,
when toggling the T/D button, or if DTR drops and either &D2 or &D3 is set. If &D3
is set and DTR drops, the modem disconnects. If the answer modem sees the Break, it
drops the connection.

NOTES
•

This command is available only during normal, direct, and synchronous
connections.

•

Y1 must be set on both modems for this command to take effect.

F-60 AT Commands

AT Commands

&Yn Designate Default User Profile
Selects user profile n (where n = 0 to 3). (Default is 0).
Designates which of four user profiles loads into active configuration at power up,
reset, or when DTR drops when &D3 is set. The modem saves this command
immediately after you enter it; you do not have to enter &W or *W. Also, when you
enter &F, this command does not change.
See also the &W, *W, and Z commands

NOTE
The &Y setting takes effect immediately. When you reset or power up the modem,
it restores the last user profile setting selected.

Zn Reset
Resets user profile n (where n = 0 to 3).
Hangs up the telephone line; clears the modem and serial port buffers; and when you
enter the next AT command sets the parity and bps rate to match the local computer.
Also, restores commands and registers that you last saved with either the &W or *W
command, or the factory defaults if you have not entered an &W or *W.
To reset the modem, type: ATZn (where n = 0 to 3).
If the OK response does not appear, type ATQ to enable result codes.
See also the &W, *W, and &Y commands.

&Zn=<dial string> Write Stored Telephone Number
Where n is a directory position from 01 to 40 and <dial string> is a string of up to 39
characters. Valid dial string characters are: 0-9, dial modifiers, and for tone dialing A,
B, C, D, #, and *. Dial strings longer than 39 characters return an error message. The
modem ignores invalid characters.
Stores a telephone number in position n of the modem’s telephone directory. When
entering a stored number with the &Zn= command you can use any dial modifiers
available with the Dial command. The &Zn= command must be the last command on
a command line.

AT Commands F-61

Commands to Change or Read Registers

Commands to Change or Read Registers
This section explains how to change S-register and :T-register values and describes
each register. Some registers control a single function. Other registers control several
functions and are bit mapped. Use bit mapped registers for reading modem status only.
Use commands or switches to change the modem’s settings.

Sn=x or :Tn=x Change the Value of a Register
Changes the value of S-register or :T-register “n” to a new value “x”.

=x Change the Value of the Last Referenced S-Register
Changes the value of the last referenced S-register or the register pointed to with the
ATSn command. For example, if the last register command used was ATS0=2, issuing
AT=4 changes the value of register S0 from 2 to 4.

? Display the Value of the Last Referenced S-Register
Displays the value of the last S-register referenced in a read, write, or point to
command.

Sn Point to New Register
Where n is an integer from 0 to 27, indicating a register. Instructs the modem to point
to the register whose location is n. This becomes the last referenced register. For
example, typing ATS1 places the pointer at register S1 and returns the command
prompt.

%Rn ; Read All Registers
%R0

Displays the contents of all S registers in decimal and hexadecimal integers in tabular
format.

%R1

Displays the contents of all :Tn=n commands in decimal and hexadecimal integers in
tabular format.

Read Configuration Register
Sn?

Where n is an integer, indicating an S-register.

:Tn?

Where n is an integer, indicating a :T-register.
Displays the contents in decimal form only of register “n”.

F-62 AT Commands

S0 Ring to Auto-Answer On
Range:

0 - 255 rings

Default:

1 ring (auto-answer enabled)
Sets the number of rings required before the modem answers. ATS0=0 disables autoanswer.

S1 Ring Counter
Range:

0 - 255 rings

Default:

0 rings
Keeps a running total of the number of rings that occur before the modem answers a
call. If no ring occurs within eight seconds after the last ring, the ring counter resets to
0.

S2 Escape Code Character
Range:

0 - 255, ASCII decimal

Default:

43 (+)
Sets the character used for the three-character escape code sequence. When the modem
is in connect state and receives the escape code sequence, it enters command state.
Setting register S2 to 0 disables the escape code character. See register S12 to set the
guard time that brackets the escape code character.

NOTE
The modem does not store this register with &W; use *W to save it.

AT Commands F-63

S3 Carriage Return Character
Range:

0 - 127, ASCII decimal

Default:

13 (carriage return)
Sets the character recognized as a carriage return. The carriage return terminates
command lines and result codes.

NOTE
The modem does not store this register with &W; use *W to save it.

S4 Line Feed Character
Range:

0 - 127, ASCII decimal

Default:

10 (linefeed)
Sets the character recognized as a line feed. The line feed character follows the carriage
return at the end of command lines and result codes.

NOTE
The modem does not store this register with &W; use *W to save it.

S5 Backspace Character
Range:

0 - 32, ASCII decimal

Default:

8 (backspace)
Sets the character recognized as a backspace.

NOTE
The modem does not store this register with &W; use *W to save it.

F-64 AT Commands

S6 Wait Before Dialing
Range:

2 - 255 seconds

Default:

2 seconds
Sets the length of the pause after off hook before the modem dials. The modem always
pauses for a minimum of two seconds, even if S6 is set less than 2.

NOTES
•

•

The modem does not store this register with &W; use *W to save it.

S7 Wait for Carrier After Dial
Range:

0 - 255 seconds

Default:

60 seconds
Sets the length of time that the modem waits for:
•

carrier from remote modem before hanging up (originate or answer mode)

•

ring back (originate mode only, and only if either X3 or X4 is set)

•

dial tone when the “W” dial modifier is encountered in a dial string

•

quiet answer when the “@” dial modifier is encountered in a dial string

NOTE
The modem does not store this register with &W; use *W to save it.

AT Commands F-65

S8 Pause Time for Dial Delay
Range:

0 - 255 seconds

Default:

2 seconds
Sets the length of time to pause when the modem encounters the comma pause dial
modifier (“,”).

NOTE
The modem does not store this register with &W; use *W to save it.

S9 Carrier Detect Response Time
Range:

0 - 255 tenths of a second

Default:

6 (0.6 seconds)
Determines how long a signal must be present before the modem recognizes it as a
carrier.

NOTES
•

The modem does not store this register with &W; use *W to save it.

•

F-66 AT Commands

S10 Delay for Hang Up After Carrier Loss
Range:

0 - 255 tenths of a second

Default:

60 (6 seconds)
Sets the length of time the modem waits before hanging up after loss of carrier,
allowing for a temporary loss. Both modems should have equal S10 values. Otherwise,
disconnect occurs when the lower value is reached. When register S10 is set to 255,
the modem functions as if carrier is always present.
After disconnecting, the modem waits for a minimum of five seconds before going off
hook again in originate mode.

NOTES
•

The modem does not store this register with &W; use *W to save it.

•

S11 DTMF Tone Dialing Speed
Range:

50 - 100 milliseconds

Default:

75 milliseconds
Sets the length of time after the last tone was sent and before the next tone is sent when
the modem is dialing over a touch tone line.

NOTE
The modem does not store this register with &W; use *W to save it.

AT Commands F-67

S12 Escape Code Guard Time and Remote Access Attention Sequence
Guard Time
Range:

0 - 255 (fiftieths of a second)

Default:

50 (1 second)
Sets the minimum “quiet” time that must be present before and after entering the threecharacter escape code or the remote access attention sequence. The time delay between
each character in the escape code or remote access attention sequence must be less than
this guard time. If register S12 is set to 0, the time it takes to enter the escape code or
remote access attention sequence does not affect recognition.

NOTES
•

The modem does not store this register with &W; use *W to save it.

•

Register S12 sets the guard time that precedes and follows the attention character
sequence. For the remote access attention sequence guard time during normal
mode, S12 should be set to the same value on both the originating and answering
modems. Reliable mode uses its own timing and register S12 is ignored.

F-68 AT Commands

S14 Bit Mapped Register
Bit Position

Function

not used

command echo

Decimal Value

0 no echo
1 echo

result codes

0 result codes
1 no result codes

result type

0 short form
1 long form

dumb mode

0 smart mode
1 dumb mode

dial methods

0 tone dial
1 pulse dial

not used

originate/answer

0 answer mode
1 originate mode

S16 Bit Mapped Register, Test Options
Bit Position

Function

Decimal Value

local analog loopback

0 disabled
1 enabled

not used

local digital loopback

0 disabled
1 enabled

remote digital loopback
status (indicated by the
remote modem)

0 loopback off

initiate remote digital
loopback

0 disabled

1 loopback in progress

1 enabled

AT Commands F-69

Function

Decimal Value

initiate remote digital
loopback with self-test

0 disabled

initiate local analog
loopback with self-test

0 disabled

1 enabled

not used

NOTES
•

The modem does not support diagnostic tests in Bell 103, V.13, V.21, or V.23
modes.

•

Commands enable and disable loopback test options. Register S16 is a read-only
register that displays loopback test option status, and is available only when the
modem is in normal or direct mode. The modem supports all loopback tests at
1200 bps or higher.

S18 Test Timer
Range:

0 - 255 seconds

Default:

0 seconds (disables timer)
Sets how long the modem conducts a loopback diagnostic test. Register S18 is
available only in normal or direct mode.
When register S18 is set to 0, type AT&T0 followed by Enter to end a test.

NOTE
Register S18 is not supported for V.54 loopback tests by switch or circuit.

F-70 AT Commands

S21 Bit Mapped Register
Bit
Position

Function

Decimal Value

Telco Jack

0 default
1 not supported

1,21

CTS/RTS synchronous

0 on hook: CTS follows RTS
off hook: CTS Off until connection
After connection:
CTS Off in response to On-to-Off RTS
transition;
CTS On in response to Off-to-On RTS
transition after delay specified in S26
(&R0)
1 on hook: CTS On;
off hook: CTS Off until connection.
After connection: CTS On for
duration of carrier signal (&R1)
2 ITU-T V.13 emulates half-duplex
over a full duplex line (&R2)

3,4

DTR

0 Ignores DTR (&D0)
1 On-to-Off DTR transition: modem
enters command state (&D1)
2 On-to-Off DTR transition: modem
goes on hook (&D2)
3 On-to-Off DTR transition: modem
resets (&D3)

DCD

0 DCD always On
1 DCD On indicates data carrier is
present or indicates DCD On except
momentarily at disconnect

not used

long space
disconnect

0 off (Y0)
1 on (Y1)

1.See also register :T15 description.

AT Commands F-71

S22 Bit Mapped Register
Bit Position

Function

Decimal
Value

Description

4,5,6

result code

same as X0

options

same as X1

same as X2

same as X3

same as X4

39/61

33/67

F-72 AT Commands

make/break ratio

S23 Bit Mapped Register
Bit Position

Function

Decimal
Value

Description

Respond to Remote
Digital Loopback

disabled

enabled

0 to 300 bps

600 bps

1200 bps

2400 bps

4800 bps

9600 bps

19200 bps

38400, 57600,
and 115200 bps

even

space/none

odd

mark

disabled

550 Hz

1800 Hz

not used

1,2,3

4,5

6,7

Serial Port Bps

Parity option

Guard tones

The Respond to Remote Digital Loopback option is ignored during reliable
connections.

AT Commands F-73

NOTE
If you use register S23 to change the parity set automatically or set by -On, the
same number of data and stop bits used before the change is retained. For example,
if 8 data bits and even parity is set (-O6) and you change register S23 to odd parity,
the 8 data bits and 1 parity bit are retained. However, the parity becomes odd
instead of even, changing the Serial Port Parity command setting to -O5.

S25 Delay to DTR and Asynchronous/Synchronous Time Delay
Range:

Delay to DTR: 0 - 255 hundredths of a second
Async/sync mode: 0 - 255 seconds

Default:

Delay to DTR: 5 hundredths of a second (0.05 seconds)
Async/sync mode: 5 seconds and 0.05 seconds
Delay to DTR: During asynchronous mode and during synchronous mode with &M2
or &M3 set, the modem ignores an On-to-Off transition of DTR that is less than the
register S25 time delay.
Asynchronous/synchronous time delay: Register S25 has two functions when &M1 is
set. First, it sets the number of seconds the modem waits to check DTR after
establishing a connection. This allows enough time to disconnect the modem from an
asynchronous terminal and attach it to a synchronous computer without forcing the
modem back to command state. Then, after this time delay, the Delay to DTR time
delay described above takes effect when loss of DTR occurs.

S26 RTS to CTS Delay Interval
Range:

0 - 255 hundredths of a second

Default:

1 hundredth of a second (0.01 seconds)
When Clear To Send (CTS) tracks Request To Send (RTS) and the modem detects an
Off-to-On transition of RTS, register S26 sets how long the modem waits before
turning on CTS. CTS tracks RTS when either &R0 or &R2 is set.

NOTE
The modem uses this register during synchronous operation only.

F-74 AT Commands

S27 Bit Mapped Register
Bit Position

Function

Decimal
Value

Description

0,1

transmission mode

asynchronous
mode (&M0)

asynchronous/
synchronous
mode (&M1)

synchronous
dial stored
number mode
(&M2)

synchronous
manual dial
mode (&M3)

leased line off
(&L0)

2-wire leased
line on (&L1 or
&L3)

4-wire leased
line on (&L2 or
&L4)

synchronous
transmit

default

clock source

&X1

&X2

not supported

0
1

ITU-T V.22bis/
V.22 (B0)
Bell 212A when
supported (B1)

2-3

4,5

leased-line
operation

answer tone when
at 1200 bps

not used

AT Commands F-75

:T0=n Timer for V.22bis, V.22, and V.32 Modes During Multi-Protocol
Answer
Range:

Where n is an integer from 0 to 255 representing tenths of a second

Default:

40 (4 seconds)
This command requires 1200 bps or higher operation with %F0%L1 set.
Determines how long the modem attempts to establish a V.32, V.22bis, or V.22
connection before attempting to establish a V.23 split speed or V.21 connection.
During this period, the modem sends V.22bis or V.22 carrier.

:T1=n Timer for V.23 Split-Speed Mode During Multi-Protocol Answer
Range:

Where n is an integer from 0 to 255 representing tenths of a second.

Default:

30 (3 seconds)
This command requires 1200 bps or higher operation with %F0%L1 set.
When the modem is unable to establish a V.32, V.22bis, or V.22 connection, :T1
determines how long the modem attempts to establish a V.23 split-speed connection
before attempting a V.21 or V.23 half-duplex connection. During this period, the
modem sends a V.23 forward channel carrier.

NOTE
If :T1 is set to 0, the modem does not send a V.23 forward channel carrier during
the multi-protocol answer sequence.

:T2=n Timer for V.21 Mode During Multi-Protocol Answer
Range:

Where n is an integer from 0 to 255 representing tenths of a second.

Default:

0 (V.23 half duplex disabled)
This command requires 1200 bps or higher operation with %F0%L1\N3 set.
When the modem is unable to establish a V.32, V.22bis, V.22, or V.23 split-speed
connection, :T2 determines how long the modem attempts to establish a V.21
connection before attempting a V.23 half-duplex connection. During this period, the
modem sends V.21 carrier.
Set :T2=20 (2 seconds) when including V.23 half duplex in the multi-protocol answer
modem.

F-76 AT Commands

NOTE
If :T2 is set to 0, V.23 half-duplex connections are not attempted. The modem
attempts to establish a connection for the length of time specified by register S7
before hanging up.

:T3=n Timer for V.21 and V.23 Answer Tone Duration
Range:

Where n is an integer from 0 to 33 representing tenths of a second.

Default:

33 (3.3 seconds)
This command requires either V.21 operation (%F0 is set and the modem speed is 300
bps) or V.23 operation (%Fn, where n=1, 2, or 3).
When the answering modem is set for V.21 or V.23 operation, :T3 determines the
duration of the V.25 answer tone that is sent to the originating modem. When :T3 is set
to 0, no answer tone is sent. All V.21 and V.23 answers begin with two seconds of
silence unless :T3 is set to 0.
When the originating modem is set for V.21 or V.23 operation, :T3 determines how
long the modem waits after detecting answer tone before proceeding with the
connection. When :T3 is set to 0, the originating modem does not wait for answer tone.

:T4=n Timer for Line Turnaround Delay - Carrier On
Range:

Where n is an integer from 0 to 255 (in increments of 12.5 milliseconds).

Default:

20 (250 milliseconds)
This command takes effect only during normal mode V.23 half-duplex connections.
After the modem turns the carrier off, this command determines the minimum time the
modem waits for the remote modem to respond before turning carrier back on again to
resume sending data.

:T5=n Timer for V.23 Half-Duplex Intercharacter Delay
Range:

Where n is an integer from 0 to 255 (in increments of 12.5 milliseconds).

Default:

7 (87.5 milliseconds)
This command takes effect only during normal mode V.23 half-duplex connections.
Sets the length of time the modem waits after transmitting the last data character in the
transmit buffer before turning carrier off. :T5 may need to be adjusted if the local
computer intercharacter time causes excessive line turnarounds.

AT Commands F-77

:T6=n Timer for DCD Turn On Delay
Range:

Where n is an integer from 0 to 255, representing milliseconds

Default:

200 milliseconds (2 tenths of a second)
This command takes effect during only normal mode V.23 half-duplex connections.
Sets how long the modem waits after carrier goes on before it starts looking for data.
This command may be set to exclude the turn on noise that occurs when DCD turns On
during V.23 half-duplex connections.
If :T6 is set to 0, the modem waits 256 milliseconds before looking for data.

:T7=n Timer for False Answer Abort
Range:

Where n is an integer from 0 to 255, representing seconds

Default:

60 seconds
Setting :T7=0 disables this timer.
This command takes effect only when the modem falls back to a normal mode V.23
half-duplex connection.
Sets the amount of time the modem waits before hanging up when it receives no data
from the local computer. If this command is set to a value greater than zero, the timer
starts when the modem connects. If the modem does not receive data from the local
computer in the specified time, it hangs up.

:T9=n Primary XON Flow Control Character
Range:

Where n is a decimal from 0 to 255, representing an 8-bit character.

Default:

11 hexadecimal (or 17 decimal) <DC1>
Defines the character used for primary XON flow control on the modem and serial
ports. Enable primary flow control with \Q1, \Q4, \G1, or \G2.

NOTE
With modem port flow control, both modems must have the same primary flow
control characters set during normal connections.

F-78 AT Commands

:T10=n Primary XOFF Flow Control Character
Range:

Where n is a decimal from 0 to 255, representing an 8-bit character.

Default:

13 hexadecimal (or 19 decimal) <DC3>
Defines the character used for primary XOFF flow control on the modem and serial
ports. Enable primary flow control with \Q1, \Q4, \G1, or \G2.

NOTE
With modem port flow control, both modems must have the same primary flow
control characters set during normal connections.

:T11=n Secondary XON Flow Control Character
Range:

Where n is a decimal from 0 to 255, representing an 8-bit character.

Default:

F9 hexadecimal (or 249 decimal)
Defines the character used for secondary XON flow control on the modem’s serial port.
For secondary flow control to take effect, you must set either -F1\Q1 or -F1\Q4.

:T12=n Secondary XOFF Flow Control Character
Range:

Where n is a decimal from 0 to 255, representing an 8-bit character.

Default:

FB hexadecimal (or 251 decimal)
Defines the character used for secondary XOFF flow control on the modem serial port.
For secondary flow control to take effect, you must set either -F1\Q1 or -F1\Q4.

:T13=n Automode Timer
Range:

Where n is an integer from 0 to 255, representing tenths of a second.

Default:

15 (1.5 seconds)
Sets a timer to allow modems to connect in Automode. If the originating modem is set
to 2400 bps or lower and has a problem connecting to your modem, we recommend
increasing the value of this command to 40 (4 seconds) on the answering modem.

NOTE
Use :T13 only when %L3 is in effect.

AT Commands F-79

:T14=n Connect Message Delay Timer
Range:

Where n is an integer from 0 to 255, in 100 millisecond intervals.

Default:

0
Specifies how long to wait before or after a connect message before CTS, DSR, DCD
go high. Use this command with @Cn (where n=0 or 1).

:T15=n V.24 Control Register
Range:

Where n is an integer from 0 to 255 (see chart below).

Default:

159
This command is bit-mapped and used as follows:
Bit
Position

Function

Description

CTS is not affected by synchronous and direct
mode retrains

CTS is lowered during synchronous and direct
mode retrains

CTS is not affected by leased-line restoral or dial
backup operation

CTS is lowered during leased-line restoral or dial
backup operation in synchronous and direct modes

RTS is ignored while not connected when &R0 or
&R2 set

CTS follows RTS when not connected when &R0
or &R2 set

DTR operates according to &D setting in leasedline operation

DTR is ignored in leased line while establishing a
connection and while connected, regardless of the
&D setting. DTR operates according to the &D
setting during switched line and dial backup
operation

Raising DTR forces the modem off hook in leasedline mode when the modem is idle

F-80 AT Commands

Function

Description

Raising DTR does not force the modem off hook in
leased-line mode when the modem is idle,
regardless of the &D setting

No synchronous clocks until connection

Synchronous clocks always On (only valid in
synchronous by switch)

DCD LED follows connection status

DCD LED always follows modem carrier when
&C1 is set

V.32 answer tone without phase reversals

V.32 answer tone with phase reversals

:T16=n CTS Turn On Delay Timer
Range:

Where n is an integer from 0 to 255 (in increments of 12.5 milliseconds)

Default:

0
After DCD and/or DSR have been turned On while connecting, determines how long
the modem waits before turning On CTS.

:T17=n V.32/V.32bis Connection Training Timer
Range:

Where n is an integer from 0, 5 to 32

Default:

0, use dynamic training sequences – equivalent to a setting of 28
This register controls the length of the training sequences exchanged when trying to
establish V.32 and V.32bis connections.
Reduces the time required to establish a connection by setting :T17 to a value less than
28; this increases the modem’s sensitivity to noise on the line.
Reduces the modem’s sensitivity to noise by setting :T17 to a value greater than 28;
this lengthens the time required to make a connection.

AT Commands F-81

:T18=n Busy Out When DTR is Low Timer
Range:

Where n is an integer from 0 to 255 seconds

Default:

0
When DTR is low, the modem goes off hook and busies out the line after the time set
by :T18 expires. When DTR is raised, the modem re-enters command state. &Dn
(where n=1, 2, or 3) must also be set.
Setting :T18=0 disables this feature.

NOTE
Manual Dial (:Dn) cannot be used when :T18 is in effect. :D0 must be set when
:T18 is set to a non-zero value.

:T19=n Bit Mapped Register
Range:

Where n is an integer from 0 to 255 (see below for the valid values for n)

Default:

1
This command controls MNP link control and is used as follows:
Bit Position

Function

Description

Modem keeps a non-MNP10 1200 bps
connection if no MNP link activity is
received from the remote modem.

Modem disconnects a non-MNP10 1200 bps
connection if no MNP link activity received
from remote modem for two minutes.

:T22 DSR Timer
Range:

Where n is an integer from 0 to 255 (in increments of 12.5 milliseconds)

Default:

34 (425 milliseconds)
After DCD and/or CTS drop, :T22 identifies how long the modem waits before DSR
is dropped when disconnecting. For example, if \D2 and &C1 are set, when DCD and
CTS drop, the modem then waits the amount of time specified by :T22 before dropping
DSR.

F-82 AT Commands

:T23 Bit Mapped Register
Bit Position

Function

0-3

not used

Rate negotiation at
startup

5-7

Decimal
Value

Description

At the start of a
V.32 connection,
makes modem
examine line
quality and set
speed
accordingly

disabled

not used

:T26 Bit Mapped Register
Bit Position

Function

Description

Enables 2-second billing
delay

Disables 2-second billing
delay. This bit decreases
connection time, but may
affect attaining
connections

Normal answer tone
length in V.32 mode

Shortens answer tone
length in V.32 mode

AT Commands F-83

:T28 Bit Mapped Register
Default:

0
This register is used with the #CID=n and *T commands for the Caller Number
Delivery (CND) feature. To enable the recording of the CND number, Bit 0 must be
set to 1 (On).
Bit Position

Function

Description

does not record CND
number or display CND
message in \S report

records CND number and
displays CND message in
\S report

disables Alternate CND
message format

enables Alternate CND
message format

does not display CND
message if Q2 is set

displays CND message if
Q2 is set

enables auto-answer,
depending on the register
S0 setting

disables auto-answer if an
“O” or “P” is received in
the CND message

F-84 AT Commands

:T42=n V.34 Connection Speed Selection
0

Default V.34 connection speed selection

Highest V.34 connection speed selection (about 2 speeds above default)

Higher V.34 connection speed selection (about 1 speed above default)

Default V.34 connection speed

Lower V.34 connection speed (about 1 speed below default)

Lowest V.34 connection speed (about 2 speeds below default)
This register allows the user to change the V.34 connection speed according to line
quality. We recommend that you leave this register at its default setting.
If you notice that your modem falls back during V.34 connections, or that you are
seldom able to make 28800 connections, you can try the lower settings of this register.

AT Commands F-85

:T49=n Bit Mapped Register
Range:

Where n is an integer from 0 to 255

Default:

15 (all types auto-answer using Distinctive Ring)
Controls which of four Distinctive Ring types (Type 1, Type 2, Type 3, or Type 4)
automatically answers when a RING signal is received. See also register :T50.
Bit Position

Function

Description

Type 1 disabled

Type 1 enabled

Type 2 disabled

Type 2 enabled

Type 3 disabled

Type 3 enabled

Type 4 disabled

Type 4 enabled

4-7

F-86 AT Commands

not used

:T50=n Bit Mapped Register
Range:

Where n is an integer from 0 to 255

Default:

15 (all types send RING message)
Controls which of four Distinctive Ring types (Type 1, Type 2, Type 3, or Type 4)
sends a RING message to the host. Also lets you optionally send a unique message
(RING1, RING2, RING3, RING4) to further identify which line is receiving the RING
signal. See also register :T49.
Bit Position

Function

Description

Type 1 disabled

Type 1 enabled

Type 2 disabled

Type 2 enabled

Type 3 disabled

Type 3 enabled

Type 4 disabled

Type 4 enabled

4-6
7

not used
0

unique RING message
disabled

unique RING message
enabled

AT Commands F-87

Glossary

This glossary lists terms that relate to modem operations. The following table
describes each term.
Term

Definition

Adaptive Packet Assembly

The process by which MNP automatically
adjusts the size of data packets based on the
quality of the telephone line. When the line
quality is good and there are few
retransmissions, the size of the packets
increases. When the line quality is poor and
retransmissions are frequent, the size of the
packets decreases in order to maintain high
throughput.

Adverse Channel Enhancements
(ACE)

Optimizes performance of the modem when
operating under poor line quality conditions.

Analog transmission

Transmission method by which data is sent as
a continuous range of changes in amplitude or
frequency. Standard telephone lines use analog
transmission.

Answer modem

The modem that emits answer tone at off hook.
Can only establish a connection with an
originating modem.

Answer tone

The tone an answering modem emits before
carrier is exchanged.

Asynchronous

Data communications using an asynchronous
computer. Data is usually sent using start/stop
bit protocol and 8 bits (the most significant bit
may be a parity bit).

AT Mode

The state that the modem is in when it is using
the Hayes AT command set.

Glossary-1

Glossary-2

Term

Definition

Attention code

The AT characters tell the modem that a
command follows.

Auto-answer mode

The state in which the modem automatically
answers the telephone when it rings.

Auto-reliable mode

The mode in which the modem can answer
calls and establish an asynchronous connection
both with modems that support MNP or LAPM
error correction and with modems that do not
support error correction.

Automatic speed matching

The ability of the modem to automatically
adjust its modem port speed to the speed of the
remote modem.

Bell 103

Bell 103 protocol is for 300 bps full-duplex
connections. Bell 103 is not supported for
synchronous connections; digital (loop 1A)
and analog (V.54 loop 3) loopbacks; LAPM
connections.

Bell 212A

Bell 212A protocol is for 1200 bps full-duplex
connections.

Bps rate

The rate at which information is sent. A unit of
measure equal to the number of bits
transmitted or received per second. Sometimes
referred to as speed or communications rate.

Bps rate adjust

The ability of the modem to automatically
adjust its serial port speed to match the
connection speed.

Caller Number Delivery (CND)

A service available from telephone companies
in some parts of the USA and other countries.
With this service, the telephone company
sends information (such as the telephone
number) about the calling party with the RING
signal to the party being called.

Caller ID (CID)

See Caller Number Delivery.

Carrier

The frequency exchanged by modems used to
transmit and receive data.

Term

Definition

CCITT

(Now ITU-T) International Telegraph and
Telephone Consultative Committee, the
former name for the international organization
that decides upon recommended
communication protocol standards. See also
ITU-T.

Carrier Detect (CD)

A V.24 (EIA232) signal sent from the modem
to the local computer, usually indicating that
the modem has detected a carrier signal over
the communications line.

Cellular network

A cellular service available to cellular phone
users by subscription. The service area is
usually subdivided into geographical cells,
each with its own radio tower (cell site). The
modem making the call through a cellular
phone is the cell-side or remote site and one
using a conventional phone is the land-side or
central site.

Command response

The OK response character that is sent to your
terminal or computer to indicate the modem is
ready to enter AT mode commands.

Command state

The state the modem is in when it can accept
commands that you enter at the keyboard.

Compromise equalization

A method of compensating for the differences
in attenuation at different frequencies.

Configuration settings

The command and register settings that
determine how the modem communicates over
the serial port and modem port.

Connect state

The state the modem is in when transmitting or
receiving data over the communications line.

Cyclic Redundancy Check
(CRC)

A method of error-checking used by MNP,
where the sender and receiver both perform a
polynomial algorithm on each data packet
transmitted over the communications line. If
the results do not match, a transmission error
occurred and the packet is retransmitted.

Glossary-3

Glossary-4

Term

Definition

Clear To Send (CTS)

A V.24 (EIA232) signal sent from the modem
to the local computer, usually indicating that
the modem is ready to receive data from the
local computer.

Data compression

A technique that combines duplicate characters
and recodes characters based on the frequency
and/or order in which they appear, to achieve
increased throughput.

Data link layer

The part of MNP that handles the actual
exchange of data between the two modems.

Data Carrier Detect (DCD)

See Carrier Detect.

Default setting

A setting that the modem always uses unless
otherwise specified.

Digital transmission

Transmission method by which data is sent as
a stream of electrical pulses. Each pulse is an
off or on electrical current that represents a 0 or
1 data bit. Computers and terminals use digital
transmission.

Distinctive Ring

A service available from some telephone
companies that allows the detection of four
types of different rings. Distinctive Ring works
before the modem goes off hook. When
available in a phone service area, it allows the
assignment of several phone numbers to one
phone line. For each phone number assigned to
the same line, a different ring signal is sent to
the modem.

Data Set Ready (DSR)

A V.24 (EIA232) signal sent from the modem
to the local computer, usually indicating that
the modem is ready to establish a connection.

DataTerminal Ready (DTR)

A V.24 (EIA232) signal sent from the local
computer to the modem, usually indicating that
the local computer is ready to begin
communication.

Dumb mode

The state in which the modem does not
recognize commands or send result codes.

Term

Definition

Dynamic Transmit Level
Adjustment

The capability to automatically calculate
optimal transmit levels to compensate for
cellular telephone signal distortion.

EIA

Electronic Industries Association.

Escape code

A series of three consecutive characters
(preceded and followed by a guard time of one
second or user-selectable setting) that is sent to
the modem, causing it to exit connection state
and enter command state.

Factory default switch settings

The configuration switch settings that are in
effect when the modem is shipped from the
factory.

Flow control

The use of characters or V.24 (EIA232) signals
to start and stop the flow of data to avoid data
loss during buffering.

Full duplex

Communication method by which data can be
transmitted in two directions simultaneously.

Guard time

An interval of time that must be present before
the first character and after the last character of
the escape code in order for the modem to
recognize the escape code and enter command
state. Also, the time that precedes and follows
the remote access attention character sequence.

Guard tone

A constant tone generated by the answering
modem during V.22 and V.22bis connections.

Half duplex

Communication method by which data can be
transmitted in two directions, but in only one
direction at a time.

ITU-T (Formerly CCITT)

International Telegraph and Telephone Union
— Telecommunication Standardization
Section, the international organization that
decides upon recommended communication
protocol standards.

ITU-T V.21

The V.21 protocol is used for 300 bps fullduplex connections. V.21 mode is not
supported for synchronous connections; V.54
digital and analog; or LAPM connections.

Glossary-5

Glossary-6

Term

Definition

ITU-T V.22

The V.22 protocol is used for 1200 bps and
600 bps full-duplex connections. The version
of V.22 your modem supports is Alternative B.

ITU-T V.22bis

The V.22bis protocol enhances V.22 by
adding 2400 bps full-duplex connections.

ITU-T V.23

The modem supports two V.23 modes: oneway forward channel at 1200 bps with a 75 bps
back channel; and main channel half duplex at
1200 bps. V.23 mode is not supported for
synchronous connections; V.54 digital and
analog loopbacks; leased-line operation; or
MNP and LAPM connections.

ITU-T V.32

The ITU-T V.32 protocol is for full-duplex
data transfer over general switched telephone
networks at 9600 and 4800 bps. V.32 employs
echo cancellation and trellis coded modulation.

ITU-T V.32bis

An MNP or LAPM error-free asynchronous
connection at 14400, 12000, 9600, 7200, or
4800 bps with another modem that supports
MNP or LAPM. The ITU-T V.32bis
specification enhances V.32 by adding 14400,
12000, and 7200 bps speeds and special rate
sequences to shorten speed upshifting and
downshifting.

ITU-T V.34

An MNP or LAPM error-free asynchronous
connection at 28800, 26400, 24000, 21600,
19200, 16800, 14400, or 33600 bps with
another modem that supports MNP or LAPM.
The V.34 protocol being adopted by the ITU-T
provides several modulation enhancements to
make the most of the new, more capable
telephone networks. It operates better over
noisy lines and holds connections more
consistently. V.34 offers full-duplex data
transfer over general switched telephone
networks at several speeds ranging from 14400
bps to 28800 bps, depending on line conditions
encountered during the connection.

Term

Definition

Link Access Procedure for
Modems (LAPM)

An HDLC error correction protocol for use
with error-correcting modems. Part of the ITUT V.42 protocol.

Local computer

The computer the modem is attached to via the
serial port.

Local system

The modem and the computer it is attached to.

Microcom Networking Protocol
(MNP)

A data communications protocol that allows
error-free interactive communications with a
variety of computers or terminals over
ordinary voice-grade telephone lines.

Mode Indicator/Mode Indicator
Common (MI/MIC)

Allows the modem to be used with dial-back
security devices and Bell 801-type automatic
calling units.

MNP reliable link

Communications established with a remote
computer, using the Microcom Networking
Protocol to perform error checking and
correction.

Modem

MOdulator-DEModulator. A device that
permits a computer to communicate with other
computers or terminals over analog telephone
lines. The local modem converts digital input
from the local computer into analog signals,
which are then transmitted over the telephone
line. The remote modem on the other end of the
connection reconverts the analog signals into
digital signals, which are then transmitted to
the remote computer.

Modem port

Modem-to-remote system connection. The
port through which analog signals are
exchanged over the telephone line.

Multi-protocol auto-answer

The state in which the modem can auto-answer
incoming calls and establish a connection at
any speed from 28800 bps or lower. The
modem can connect using any of the following
modulation protocols: V.34, V.32bis, V.32,
V.22bis, V.22 (1200 bps only), V.21, V.23
split speed (1200 bps transmit/75 bps receive
only), V.23 half-duplex, Bell 212A, and Bell
103.

Glossary-7

Glossary-8

Term

Definition

Noise

Unwanted signal disturbances over a
communication line, such as variation in
voltage or current, that can affect the integrity
of data transmitted over the line or cause the
loss of connection.

Normal operation

A standard asynchronous connection that does
not use error correction, established with any
V.34, V.32bis, V.32, V.23, V.22bis, V.22,
V.21, Bell 212A, or Bell 103 modem.

Off hook

The condition that is similar to picking up a
telephone receiver. The modem goes off hook
to dial or answer and remains off hook while
connected.

On hook

The condition that is similar to hanging up a
telephone receiver. You cannot enter the
connect state when the modem is on hook.

Online

Connected to a remote system.

Optimized Data Phase

Redesign of the MNP protocol header, which
reduces the number of overhead bytes per data
packet.

Originate modem

The modem that emits carrier in response to
answer tone from a remote answer modem.

Parity

A method of error-checking by which an extra
bit is added to every character. The value of the
bit is set so that the sum of the data bits and the
parity bit is always either even (for even parity)
or odd (for odd parity). For example, if parity
is set to even, and a character is received with
a sum that is odd, the computer knows that an
error has occurred.

Protocol

A set of rules or parameters for communicating
between two computers.

Postal Telephone Telegraph
(PTT)

A local government’s organization that
governs internal and international
communications.

Pulse dialing

Telephone dialing accomplished by sending a
series of pulses, which sound like loud clicks.

Term

Definition

Reliable operation

An MNP or LAPM error-free connection with
another MNP or LAPM modem.

Remote system

Any computer with which you communicate
using the modem and a communications line.

Result code

A message the modem sends to the local
computer containing information about the
state of the modem.

Retrain

A method of re-establishing a better quality
connection when the quality of the current
connection causes data to be continuously
retransmitted.

Request To Send (RTS)

A V.24 (EIA232) signal sent from the local
computer to the modem, usually indicating that
the computer is ready to begin sending data to
the modem.

Serial port

The port through which digital signals are
exchanged between the modem and the local
computer.

Smart mode

The state in which the modem recognizes
commands and sends result codes.

Spoofing

A technique to enhance data throughput.
During a parallel-port connection, the modem
sends messages to the remote computer to
maintain the data flow without interruption.
This emulates (spoofs) a protocol typically
used in serial communications.

Synchronous

Data communications using a synchronous
computer. Data transmission is clock-driven
and does not use start/stop protocol.

Tone dialing

Telephone dialing accomplished by sending a
series of tones.

Glossary-9