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EK-VT100-UG-001

August 1978

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Document:	VT100 User Guide
Order Number:	EK-VT100-UG
Revision:	001
Pages:	94
Original Filename:	http://bitsavers.org/pdf/dec/terminal/vt100/EK-VT100-UG-001_VT100_User_Guide_Aug78.pdf

OCR Text

VT100 USER GUIDE
EK-VT100-UG-001

1st Edition, August 1978

Copyright @ 1978 by Digital Equipment Corporation
The material in this manual is for informational purposes and
is subject to change without notice.
Digital Equipment Corporation assumes no responsibility for
any errors which may appear in this manual.

Printed in U.S.A.

This document was set on DIGITAL's DECset-8000 computerized typesetting system.

The following are trademarks of Digital Equipment Corporation.
Maynard. Massachusetts:
DIGITAL
DEC
PDP
DECUS
UNIBUS

DECsystem-10
DECSYSTEM-20
DIBOL
EDUSYSTEM
VAX
VMS

MASS BUS
OMNIBUS
OS/8
RSTS
RSX
lAS

CONTENTS

Page

CHAPTER 1

OPERATOR INFORMATION

PART 1 - KEYBOARD CONTROLS AND INDICATORS .......................................... 1-4
PART 2 - SET-UP MODE ............................................................................................... 1-7
SET-U P Features at a Glance ............................................................................... 1-7
SET -U P A ................................................................................................................ 1-7

SET-UP.B ................................................................................................................. 1-8
Determining What a SET-UP Feature Does ...................................................... 1-9
How to Change a SET-UP Feature ................................................................... 1-10
SETTING THE ANSWERBACK MESSAGE .............................................................. 1-12
SAVING SET-UP FEATURES ...................................................................................... 1-12
RECALLING SET-UP FEATURES ............................................................................... 1-13
RESETTING THE TERMINAL. ..................................................................................... 1-13
PART 3 - DEFINITION OF EACH SET-'-UP FEATURE ............................................. 1-13
PART 4 - SELF-TESTING THE VT1 00 ...................................................................... 1-15
Self-Test Error Codes .......................................................................................... 1-15
PART 5 - WHAT TO DO IN THE EVENT OF A PROBLEM .................................... 1-16

CHAPTER 2

INSTALLATION, INTERFACE INFORMATION,
AND SPECIFICATIONS

SITE CONSiDERATIONS ...............................................................................................2-3
UNPACKING AND INSTALLATION .............................................................................2-3
USER MAINTENANCE ...................................................................................................2-6
INTERFACE INFORMATION .........................................................................................2-6
EIA Interface ...........................................................................................................2-6
Electrical Characteristics .......................................................................................2-7

iii

CONTENTS (CONT)

Page
OPTIONAL 20 mA CURRENT LOOP INTERFACE .....................................................2-7
Electrica I Characteristics .......................................................................................2-8
EXTERNAL VIDEO CONNECTIONS .............................................................................2-9
Composite Video Output (J9) ..............................................................................2-9
Video Input (J8) ...................................................................................................2-10
VT100 SPECiFiCATIONS ........................................................................................... .2-1 0
HOW TO ORDER HARDWARE DOCUMENTATION ..............................................2-12

CHAPTER 3

PROGRAMMER'S INFORMATION

THE KEyBOARD ..............................................................................................................3-4
COMMUNICATION PROTOCOLS .............................................................................3-10
TERMINAL CONTROL COMMANDS ........................................................................3-12
Control Cha racters ...............................................................................................3-12
Escape Sequences ...............................................................................................3-13
ANSI COMPATIBLE MODE ........................................................................................3-14
Cursor Movement Commands ...........................................................................3-14
Line Size (Double-height and Double-width) Commands ............................3-14
Character A ttri butes ............................................................................................3-14
Erasing ...................................................................................................................3-14
Programmable LEDs ...........................................................................................3-14
Character Sets (GO and G 1 Designators) ........................................................3-15
Scrolling Region ......... :.........................................................................................3-15
Tab Stops ..............................................................................................................3-15
Modes ....................................................................................................................3-15
REPORTS ......................................................................... ;.............................................. 3-15
Cursor Position Report. .......................................................................................3-15
Status Report .......................................................................................................3-15
What Are You .......................................................................................................3-16
Reset ......................................................................................................................3-16
Confidence Tests .................................................................................................3-16
VALID ANSI MODE ESCAPE SEQUENCES (detailed) ...........................................3-17
CPR Cursor Position Report - VT100 to Host.. ............................................3-17
CU B Cursor Backward - Host to VT100 and VT100 to Host .................... 3-18
CU D Cursor Down - Host to VT100 and VT100 to Host ........................... 3-18
CUF Cursor Forward - Host to VT100 and VT100 to Host. ...................... 3-18
CUP Cursor Position .........................................................................................3-18
CUU Cursor Up - Host to VT100 and VT100 to Host ................................ 3-19
DA Device Attributes ................... '" ..................................................................3-1 9
DECALN Screen Alignment Display (DEC Private) .....................................3-19
DECANM ANSI/VT52 Mode (DEC Private) .................................................3-19
DECARM Auto Repeat Mode (DEC Private) ................................................3-19
DECAWM Autowrap Mode (DEC Private) ....................................................3-20
D ECCO LM Column Mode (D EC Private) .......................................................3-20
DECCKM Cursor Keys Mode (DEC Private) .................................................. 3-20
DECDHL Double Height Line (DEC Private) .................................................3-20
iv

CONTENTS (CaNT)

Page

D ECDWL Double-Width Line (DEC Private) ................................................ 3-20
DECGOFF Graphics Processor Off (DEC Private) ........................................ 3-20
DECGON Graphics Processor On (DEC Private) .......................................... 3-21
DECHCP Hard Copy (DEC Private) .................................................................3-21
DECID Identify Terminal (DEC Private) .........................................................3-21
DECIN LM Interlace Mode (DEC Private) ......................................................3-21
DECKPAM Keypad Application Mode (DEC Private) ................................. 3-21
DECKPNM Keypad Numeric Mode (DEC Private) ...................................... 3-21
DECLL Load LEDs (DEC Private) ....................................................................3-22
DECOM Origin Mode (DEC Private) ............................................................... 3-22
DECRC Restore Cursor (DEC Private) ............................................................ 3-22
DEC REPTPARM Report Terminal Parameters ............................................ 3-22
DEC REQTPARM Request Terminal Parameters ........................................ 3-22
DECSC Save Cursor (DEC Private) .................................................................3-23
DECSCLM Scrolling Mode (DEC Private) .....................................................3-24
DECSCNM Screen Mode (DEC Private) ........................................................ 3-24
DECSTBM Set Top and Bottom Margins (DEC Private) ............................. 3-24
DECSWL Single-width Line (DEC Private) ...................................................3-24
DECTST Invoke Confidence Test.. .................................................................. 3-24
DSR Device Status Report ..............................................................................3-25
ED Erase In Display ...........................................................................................3-25
EL Erase In Line .................................................................................................3-25
HTS Horizontal Tabulation Set .......................................................................3-26
HVP Horizontal and Vertical Position ............................................................3-26
IN D Index ...........................................................................................................3-26
LNM Line Feed/New Line Mode .................................................................... 3-2~
NEL Next Line ....................................................................................................3-26
RI Reverse Index ...............................................................................................3-26
RIS Reset To Initial State .................................................................................3-27
RM Reset Mode ................................................................................................3-27
SCS Select Character Set ................................................................................3-27
SGR Select Graphic Rendition ........................................................................3-27
SM Set Mode .....................................................................................................3-28
TBC Tabulation Clear ........................................................................................ 3-28
MODES ...........................................................................................................................3-28
ANSI Specified Modes .......................................................................................3-28
DEC Private Modes .............................................................................................3-28
VALID VT52 MODE ESCAPE SEQUENCES (detailed) ...........................................3-29

CHAPTER 4

VT100 OPTIONS

ADVANCED VIDEO OPTION - VT1XX-AA ................................................................. 4-3
Advanced Video Option Installation .................................................................. .4-4
20 mA CURRENT LOOP OPTIONS - VT1 XX-AA ...................................................... 4-6
20 mA Current Loop Option Installation ............................................................4-6
20 mA Current Loop Option Checkout.. ............................................................ .4-7
v

CONTENTS (CONT)

Page
APPENDIX A

ANSI DEFINITIONS AND NOTATION

APPENDIX B

ASCII CODE CHART

FIGURES

Figure No.
1 -1
1-2
1-3
1-4
1-5
1-6
2-1
2-2
2-3
2-4
3-1
3-2
4-1
4-2
4-3
4-4

Title

Page

VT1 00 Terminal ............................................................................. 1-2
VT100 Keyboard ............................................................................ 1-4
VT100 Terminal (Rear View) ....................................................... 1-6
SET-U P A Mode Presentation ..................................................... 1-7
SET-UP B Mode Presentation ..................................................... 1-8
SET-UP B Mode Summary .......................................................... 1-8
VT100 Terminal Dimensions .......................................................2-4
VT100 Rear View ..........................................................................2-5
20 mA Current Loop Interface ....................................................2-8
Composite Video Output ..............................................................2-9
Terminal Data Flow ....................................................................... 3-2
VT1 00 Keyboard ............................................................................3-4
VT100 Rear View ..........................................................................4-4
Advance Video Option Installation .............................................4-5
20 mA Current Loop Option ........................................................4-7
Terminal Controller Board ............................................................4-8

TABLES

Table No.
1-1
1-2
1-3
1-4
2-1
3-1
3-2
3-3
3.,.4
3-5
vi

Title

Page

Categories of SET-UP Features ................................................... 1-9
SET-UP Feature Change Summary .......................................... 1-10
Nonfatal Displayed Error Codes ................................................ 1-16
Problem Checklist ....................................................................... 1-1 7
EIA Connector Signals ..................................................................2-6
SET-UP Features and Machine States ....................................... 3-5
Alphabetic Key Codes ...................................................................3-6
Nonalphabetic Key Codes ............................................................3-6
Function Key Codes ......................................................................3-7
Control Codes Generated ............................................................. 3-8

TABLES

Table No.

3-6
3-7
3-8
3-9
3-10
3-11

Title

Page

Cursor Control Key Codes ............................................................3-8
VT52 Mode Auxiliary Keypad Codes.......................................... 3-9
ANSI Mode Auxiliary Keypad Codes .......................................... 3-9
Specia I Graphics Characters .....................................................3-10
Control Characters ......................................................................3-12
VT 100 Escape Sequences Summary ......................................3-1 3

vii

INTRODUCTION

The VT100 terminal is designed to work very much like a typewriter. This guide
will tell you everything you need to know to use your terminal.
A checklist label is provided for making a semi-permanent record of the features,
unique functions, and mode of operation of your terminal. Place this label under
the keyboard and keep it up-to-date so that you will have a quick reference to the
basic status of your machine.

CHAPTER 1
Operator Information

MA-1986

1-2

CHAPTER 1
OPERATOR INFORMATION

The VT100 is a simple device to operate. The terminal (Figure 1-1) is basically a
typewriter that uses a video screen instead of paper and communicates with a
computer. If you can operate a typewriter, you can operate a VT100.
Chapter 1 is divided into five parts:
1.
2.
3.
4.
5.

Controls and Indicators
Setup Mode
Definition of Each Setup Feature
Self-Testing the VT100
What to do in the Event of a Problem

Part 1 shows all the controls and indicators on the terminal and summarizes
the function of each, thus providing a quick reference for these functions.
Part 2 defines the SET-UP mode and briefly summarizes its features.
Part 3 describes each feature in detail. Refer to this section if you need
further information on a feature mentioned in the SET-UP Summary provided
in Part 2.
Part 4 provides information on self-testing the VT100. It outlines the steps
required to start the built-in self-tests and how to interpret the results once
the tests have been ru n.
Part 5 provides a procedure to follow in case you encounter any problem
with the VT100. Easily recognized failures with simple corrective actions are
provided for each symptom. Check this Jist before calling for service.
1-3

OPERATOR INFORMATION
PART 1 - KEYBOARD CONTROLS AND INDICATORS
The VT100 terminal normally performs a two-part function. It is an input device to
a computer - information entered through the keyboard is sent to the computer. It
is simultaneously an output device for the computer - that is, data coming in from
the computer is displayed on the video screen. The following controls and indicators on the VT100 keyboard are illustrated in Figure 1-2.

~~BB
T'
-~

0 0 0 0
D
GDJ[!][XJrnrnGJ[IJwrnrnEJmo ~~;~E EJ 000[J
GG000000~G0wwnB 0000
ET-UP

ONONE LOLKBDOCKED
SETI
CLEAR ALL
LlNEI
SETUP
TOGGLE
CLEAR TAB TABS
LOCAL
AlB
110

TRANSMIT RECEIVE
SPEED
SPEED

801132

COLUMNS

~@000G0~00~~.~Dc:::JgJ

§;]I '"' ' 10000000[J[]ITJG@J
I
Figure 1-2

[JF1 [JF2 [JF3 [JF4

RESET

~000

0DD

VT100 Keyboard

(SET-UP Key

This key is used in conjunction with other keys to perform specific functions such as setting tabs, scrolling,
and altering terminal characteristics.

[!] [II B B Keys

ON LINE Indicator

Each of these keys causes the VT100 to transmit a
code which has a special meaning to your system.
Consult your local operating proceduresfor the meaning of these keys. In SET-UP mode the "i" and ",t."
keys increase or decrease the brightness of the display.
The ''+-'' and "-+" keys move the cursor left and right.

This indicator lights to show that the VT100 is on-line
and ready to transmit or receive messages.

IBACKSPACE IKey
This key transmits a backspace code.

LOCAL Indicator
This indicator lights to show that the terminal is off-line
and cannot communicate with the host device. In local
mode the keyboard remains active and all characters
typed are placed on the screen.

KEYBOARD LOCKED Indicator
This indicator lights to show that the keyboard has
been turned off. The VT100 is still able to receive data
from the host. This condition can be cleared by entering and exiting SET-U P mode.

L1-L4 Indicators
These indicators are turned on and off by the host.
Consult your local operating procedures for the meaning of each indicator. L 1-L4 are also used to show
self-test errors.
1-4

IBREAKI Key
This key transmits a break signal.

IPF11-lpF41 Keys
Each of these keys causes the VT100 to transmit a
code which has a special meaning to your system.
Consult your local operating procedures for the meanings of these keys.

Numeric Keypad
The numeric keypad enables numbers to be entered in
calculator fashion. Each key in the numeric keypad
generates the same character as the corresponding numeric key on the main keyboard. The IENTERI key corresponds to the IRETURNI key. These keys may also be
interpreted by the host computer as special function
keys. Consult your local operating procedures for the
meanings of these keys.

IDELETEI Key
This key causes the VT100 to transmit a delete character code to the host system. The deleted character may
or may not be erased from the screen.

SET-UP Al8

~ Key

When the terminal is in SET -U P mode this key
switches the terminal from SET-UP A to SET-UP B or
from SET-UP B to SET-UP A.

IRETURNI Key
This transmits either a carriage return (CR) code or a
carriage return (CR) and linefeed (LF) code. This is a
SET-UP selectable feature.
I LIN EFEEDI Key
This key transmits a linefeed code.

LIN E/LOCAL

~ Key

In SET-UP mode this key switches the VT100 to communicate with your system (ON LI N E) or stops the
VT100 from communicating with your system (LOCAL).

I#£l
l!J Key

ISHIFTI Key

CLEAR ALL TABS

When pressed, this key enables the uppercase function
of all keys. If a key does not have an uppercase function the SHIFT key will be disregarded.

In SET -U P A this key clears all horizontal tabs set in
the VT100.

RESET~

SET/CLEAR TA8
Key

When the terminal is in SET-UP mode this key starts
the reset sequence. This has the same result as turning
the terminal power off and then on.

Key

In SET-UP A this key sets or clears individual horizontal tabs.

ICAPSI
LOCK Key
80/132 COLUMNSr;] Key
When the terminal is in SET-UP A mode this key
switches the display line size from 80 to 132 characters per line or from 132 to 80 characters per line.

RECEIVE SPEED

Key

When the terminal is in SET-UP B mode this key steps
the terminal through the receive baud rate settings in
ascending order.

TRANSMIT SPEED

~ Key

When the terminal is in SET -U P B mode this key steps
the terminal through the transmit baud rate settings in
ascending order.

TOGGLE 1/0

~ Key

When the terminal is in SET-UP B mode this key turns
the selected operational feature on or off.

Key
When pressed in combination with the CTRL key this
key causes a bell code to be sent to the host.

This key enables the transmission of uppercase alphabetic characters only. All numeric and special symbol
keys remain in lowercase.

I~~ROLLI

Key

When first pressed, this key stops the transmission of
data from the computer to the VT100. When pressed a
second time, transmission resumes from where it was
stopped. Check your local operating procedures to ensure that your system recognizes this key.
ICTRLI Key
When pressed in combination with another key, CTRL
causes the VT100 to transmit a code which has a special meaning to your system.

ITABI Key
This key transmits a tab code.

IEsci Key
This key transmits a code which normally has a special
meaning to your system. In many applications, it tells
your system to treat the next keys pressed as a command.
1-5

OPERATOR INFORMATION
MONITOR CONTROLS
The VT100 monitor contains only one control. the power switch, which is shown in
Figure 1-3.
CAPTIVE
SCREWS (4)

ACCESS
COVER

l
d
~~~~~~~~~---

EIA
COMMUNICATIONS
CONNECTOR
EXTERNAL
VIDEO
COMMUNICATIONS

MAIN FUSE
POWER SWITCH

"\
MODEL + SERIAL
~/NUMBER LABEL

-r-r,__~===n~__~~______~__~o~ol@I~~
KEYBOARD
CONNECTOR

Figure 1-3
VT1 00 Terminal
(Rear View)

POWER
SELECTOR
SWITCH

POWER CORD
CONNECTOR

OPTIONAL 20mA
COMMUNICATION
CONNECTOR

MA-1987

Audible Indicators (Tones)
There are three audible alarms associated with the VT100: a short tone (click), a
long tone (beep), and a series of long tones.
Short Tone (click) - The short tone is sounded by the terminal whenever a key is
pressed, with the following exceptions:
• SHIFT or CTRL keys do not generate any keycJick because these keys do
not transmit any codes but only modify the codes transmitted by other
keys.
• KBD LOCKED indicator is turned on; in which case, the characters typed
are lost.
• The keycJick feature has been turned off in SET-UP mode.
Long Tone (beep) - The long tone is sounded by the terminal to indicate one of
the following conditions:
• A bell code was received from the computer.
• The cursor is eight characters away from the right margin and the margin
bell feature is enabled.
1-6

Series of Long Tones - The terminal will sound the long tone several times in
rapid succession to indicate that the nonvolatile memory (NVR) had difficulty in
reading or writing the SET-UP features. (When this occurs, check the SET-UP
features and then perform the Recall or Save operation again.)
PART 2
SET-UP MODE

Unlike most terminals, the VT100 does not use switches or jumpers to individually
turn the built-in terminal features on or off. Instead, the VT100 uses a nonvolatile
memory (NVR) which always remembers what features have been selected, as if a
switch had been set.
The selection and storage of built-in terminal features is performed in a special
mode of operation called SET-UP mode. When you enter SET-UP mode, the status
of the features stored in the temporary memory is shown on the screen. You can
then change the features and store any new feature selections either temporarily,
by leaving SET-UP mode; or on a fixed basis, by performing a Save operation. In
either case, the terminal operation will reflect the new feature selection. If a recall
operation is performed, or the terminal is reset or the terminal power is turned
OFF, all temporary feature settings are replaced by the features that have been
stored on a fixed basis.
SET-UP Features at a Glance
When entered, SET-UP mode provides two brief summaries of the current feature
status. The first presentation - SET-UP A - displays the location of the tab stops
set in the terminal and a visual ruler which numbers each character position on the
line. The second presentation - SET-UP B - summarizes the status of the other
terminal features.
SET -U P A - To enter SET -U P A, press the SET -U P key. The display will now have
a presentation similar to Figure 1-4. The bottom line of the display consists of a
"ruler" which numbers each character position available on a line. The location of
each tab stop is shown by a "T" placed above the ruler. If the tab stop(s) set are
those desired, you may exit SET-UP mode by pressing the SET-UP key again or
you may now change the tabs to meet your requirements.

SET-UP·A

TO-EXIT-PREss--SET-UP-

Figure 1-4
SET-UP A Mode Presentation

MR·1517

1-7

OPERATOR INFORMATION
SET-UP B - SET-UP B mode may only be entered from SET-UP A mode. To enter
SET-UP B from SET-UP A press the 5 key on the main keyboard. The display will
then look like Figure 1-5. Figure 1-6 summarizes the SET-U P B presentation. This
summary allows you to quickly determine what features are enabled. For additional information on a feature refer to the Definition of Each Feature section.
To exit SET-UP B press the SET-UP key.

SET-Up·B

TO-EXIT-PRESS-"SET-Up·

"SPEED' 1€OO- -'R-SPEED- ·~oo
Figure 1-5
SET-UP B Mode Presentation

SCROLL

MR-1S1a

~ (SHIFTED)

[0 = JUMP
= SMOOTH

AUTOREPEAT

[0 = OFF
l.1 = ON

WRAP AROUND

{a
{a =
=

1 =

OFF
1 = ON

SCREEN [0 = DARK BACKGROUND
1 = LIGHT BACKGROUND

NEW LINE

l.1 = ON

[0 = UNDERLINE
l.1 = BLOCK

INTERLACE

[0 = OFF
l.1 = ON

CURSOR

[0 = OFF
(OPTIONAL
DISPLAY
FOR CUSTOM
FUNCTIONS)

(USE WITH GRAPHICS)

AUTO XON XOFF

[0 = OFF

L1 = ON

1-8

T SPEED c:::::J

POWER [0 = 60 Hz
\..1 = 50 Hz

ANSIIVT52

[0 = VT52

l.1 = ANSI

BITS PER CHAR.

KEYCLICK

[0 = OFF

PARITY

L1 = ON
[0 = OFF
MARGIN BELL l.1 = ON

Figure 1-6
SET-UP B Mode Summary

5 [1:1:1:1

[0 = 7 BITS
l.1
= 8 BITS

[0 = OFF

l.1 = ON
[0 = ODD
PARITY SENSE l.1 = EVEN
MA-1988

R SPEEDc::::J

Determining What a SET - U P Feature Does
The SET-U P features are basically a series of options in the VT100 that allow the
terminal to be tailored to its operating environment. Table 1-1 lists each feature
and shows one of the following general categories:
I nsta Ilation
Computer compatibility
Operator comfort

The installation category concerns itself with the initial installation of the terminal
and any special options that may be attached to the terminal. If any terminal
options are added or removed, or the physical location of the installation is
changed, verify the settings of these SET-UP features.

Computer compatibility contains the features which must be set correctly so that
the VT100 can communicate with the host computer. An error in these settings
may cause incorrect data to be sent to or received from the computer; or an error
may prevent the VT100 from communicating with the computer. The settings for
these features must be obtained from the host computer programmer, operator, or
system manager since there are many combinations of settings designed to work
with particular computers and special software. These feature settings would normally change only when you need to communicate with a different computer or a
unique software package.

Table 1-1
Categories of SET-UP Features
SET-UP Feature
ANSI/VT52 Mode
ANSWERBACK Message
AUTO REPEAT
AUTO XON XOFF
BITS PER CHARACTER
CHARACTERS PER LINE
CURSOR
INTERLACE
KEYCLICK
LINE/LOCAL
MARGIN BELL
NEW LINE
PARITY
PARITY SENSE
POWER
RECEIVE SPEED
SCREEN BACKGROUND
SCREEN BRIGHTNESS
SCROLL
TABS
TRANSMIT SPEED
WRAPAROUND

E2]
3

Installation

Computer
Compatibility

Operator
Comfort

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

X
X
X
X
X

X
X
X

(shifted)

1-9

OPERATOR INFORMATION
The operator comfort category contains the SET-UP features designed exclusively
for the operator. These features allow the operator to tailor the VT100 to fit individual preference. These features do not affect any operations that occur between
the terminal and the computer.
The next section, Definition of Each SET-UP Feature, describes the specific function of each feature.

How to Change a SET-UP Feature
Changing any or all of the SET-UP features is a simple operation and is generally
performed by following the same basic steps.
1.

Enter SET-UP mode by pressing the SET-UP key.

Select the appropriate SET -U P mode by pressing the 5 key on the main
keyboard each time you want to switch from SET-UP A to SET-UP B or
from SET-UP B to SET-UP A.

Position the cursor above the feature switch or tab stop to be changed.
To position the cursor, the "SPACE" bar, "+-", "-+", "TAB" and "RETURN" keys may be used. Some features do not use this step since a
specific key is dedicated to changing the feature.

Change the feature setting by pressing either the 6 key on the main
keyboard or the appropriate dedicated key. Each time the key is pressed
the feature will change, generally to the opposite state.

Table 1-2 briefly summarizes the SET-UP features, the SET-UP mode you must be
in to change a given feature, and the key used to change the feature setting.

Table 1-2
SET-UP Feature
Change Summary
SET-UP Feature

Changed In
SET-UP A Mode
SET-UP B Mode

ANSWERBACK message

ANSI/VT52 mode

AUTO REPEAT

AUTO XON/XOFF

BITS PER CHARACTER

BRIGHTNESS

CHARACTERS PER LINE

tA special sequence is required for this feature. See the detailed features description.
1-10

Key Used to
Change Feature

Table 1-2
SET-UP Feature
Change Summary
(Cont)
Changed In

SET-UP Feature

SET-UP A Mode

SET-UP B Mode

CURSOR

INTERLACE

KEYCLICK

LINE/LOCAL

Key Used to
Change Feature

~
~
~

[TI
[J

MARGIN BELL

NEW LINE

PARITY

PARITY SENSE

[]

POWER

RECEIVE SPEED

SCREEN

SCROLL

~
~and~

TABS

TRANSMIT SPEED

WRAPAROUND

EJ
3

X
(shifted)

~
~

m
m
[]
1-11

OPERATOR INFORMATION
Setting the Answerback Message
Setting the answerback message is different from setting any of the other terminal
features. An answerback message can be typed into the VT100. using the following steps:
1.

Place the terminal in SET-UP B mode.

Press the I SHI FTI and [!] keys simultaneously. The terminal will respond by placing A= on the screen. (The ISHI FT' key IS required. The
I CAPS LOCKI key will not work here.)

Type the message delimiter character which may be any character not
used in the actual answerback message. The message delimiter character is not a part of the answerback message. If a mistake is made when
typing the answerback message. type the message delimiter character
again and go back to step 2. This is the only way to correct errors in the
answerback message.

Type the answerback message. The message may be up to 20 characters. including space and control characters. Control characters will be
displayed as a • character to indicate their presence in the message.

Type the message delimiter character. Once the messsage delimiter
character is typed the answerback message will disappear from the
screen.

Once the above steps have been completed the answerback message will be temporarily stored in the VT100 and can be saved with the Save operation.

Saving SET-UP Features
SET-UP features may be changed and stored on either a temporary or a fixed
basis. To temporarily store a feature. exit SET-UP mode after changing the feature;
the terminal now reacts according to the new setting. If a recall operation is performed. or the terminal is reset. or the terminal power is turned off. all temporary
feature settings are replaced by the features that have been stored on a fixed basis.
To store SET-UP feature settings on a fixed basis. perform a save operation. This is
a simple operation that is accomplished by performing the following steps:

NOTE
The save operation must be
performed at the terminal
keyboard. The computer cannot perform this operation, although it can temporarily
modify the setting of the
VT100 features.

Place the terminal in SET-UP mode.

Press the ISHIFTI and
keys simultaneously. The screen will clear and
the message "Wait" will be displayed in the upper-left corner. After a
brief wait. the terminal will return to SET-UP A mode.

Once these steps have been performed. SET-UP features which had been temporarily stored will now be stored on a fixed basis.

Recalling SET -U P Features
The temporarily stored SET-U P feature settings may differ from the settings which
have been stored on a fixed basis. If you wish to return to the fixed settings.
perform the recall operation as follows:
1.
1-12

Place the terminal in SET-UP mode.

NOTE
When a recall operation is
performed the contents of the
screen are destroyed.

Press the ISHIFTland [B] keys simultaneously. The screen will clear and
the message "Wait" will appear in the upper-left corner of the screen.
After a brief wait the terminal will return to SET-UP A mode.

Resetting the Terminal
The VT100 may be reset from the keyboard. When the terminal is reset, the terminal memory is cleared and the self-test program is run as if the terminal power
switch had been turned OFF and then back ON. To reset the terminal:

NOTE
When a reset operation is performed the contents of the
screen are destroyed.

Place the terminal in SET-UP mode.

Press the 0 key on the main keyboard. The VT100 will be reset, the
power on self-test will be run, and the terminal will react according to
the fixed SET-UP features.

PART 3
DEFINITION OF EACH SET-UP FEATURE
This section describes each SET -U P feature in detail (in
alphabetical order) and states how each feature affects
the terminal.
NOTE
Unless otherwise stated, entering SET-UP mode and changing features does not result in the loss of data displayed on
the screen.

ANSI/VT52 Mode
The VT100 terminal follows two different programming standards - American National Standards Institute (ANSI) and VT52. In ANSI mode, the VT100
will generate and respond to coded sequences per
ANSI standards X3.41-1974 and X3.64-1977. In
VT52 mode, the VT100 terminal is compatible with
previous DIGITAL software using the VT52 video terminal. Both ANSI and VT52 modes are outlined in the
programmer's section of this manual.
ANSWERBACK Message
Answerback is a question and answer sequence where
the host computer asks the terminal to identify itself.
The VT100 answerback feature provides the terminal
with the capability to identify itself by sending a message to the host. The entire answerback sequence
takes place automatically without affecting the screen
or requiring operator action. The answerback mesage
may also be transmitted by typing CTRL-BREAK.
AUTO REPEAT
The auto repeat feature allows a key to be automatically repeated at the rate of about 30 characters per
second when the key is held down for more than onehalf second. The auto repeat feature affects all keyboard keys except the following:
SET-UP
ESC
NO SCROLL

TAB
RETURN
CTRL and any key

AUTO XON/XOFF
The VT100 is capable of automatically generating synchronizing codes XON (DC1) and XOFF (DC3). The
XOFF control sequence is used to stop the transmission of data from the computer to the terminal; the
XON sequence is used to resume transmission. With
the feature enabled, the VT100 will generate the XOFF
code when one of the following events occur:
1.
2.
3.
4.

The internal buffer is nearly full
The NO SCROLL key is pressed
The terminal is placed in SET-UP mode
CTR L-S is pressed.

When the buffer empties, the NO SCRO LLl key is
pressed again, the terminal is taken out of SET -U P
mode, or CTRL-Q is pressed, the VT100 will transmit
the XO N code to resu me transmission from the computer to the terminal.
If the host computer software does not support the
XON/XOFF codes, data sent during buffer full conditions, or when the terminal is in SET-UP mode, may be
lost.
NOTE
The VTT 00 will always stop transmission when an XOFF
(DC3) code is received and will resume transmission when
an XON (DC1) code is received regardless of the A UTa
XON/XOFF feature setting.

BITS PER CHARACTER
This feature allows the terminal to transmit and receive
either 7 - or 8-bit characters. When set for 8-bit operation, bit 8 is set to a space (or 0) for characters transmitted and is ignored for a II characters received.
CHARACTERS PER LINE
The VT100 is capable of displaying either 80 or 132
characters per line. In the 80 character per line mode,
the screen is 80 characters wide by 24 lines high. In
the 132 character per line mode, the screen is 132
characters wide by 14 lines high (24 lines if the VT100
is equipped with the Advanced Video Option). In the
1-13

OPERATOR INFORMATION
132 character per line mode, the displayed lines are
physically the same width as in the 80 character per
line mode but the characters are more compact.

NOTE
When changing from 80 to 132 character per line mode or
vice-versa, the current contents of the screen are lost.

CURSOR
The VT100 offers a choice of two cursor displays to
indicate the "active positions" or where the next character will be placed on the screen. The cursor may be
displayed as either a blinking underline (-) or a blinking block (.). The cursor selection may perform an additional function; see the SGR escape sequence
definition in Chapter 3.

INTERLACE
This feature is used for high resolution options. The
interlace feature should be turned off if such an option
is not installed.

KEYCLICK TONE
The keyclick is a tone which is generated every time a
key is pressed. The keyclick may be turned on or off to
suit the operator's needs. However, research and experience has shown that an operator is more accurate
when there is an audible feedback from the keyboard.
Like the bell tone, the keyclick volume is not adjustable.

LINE/LOCAL
The LINE/LOCAL feature allows the operator to easily
place the terminal in either an ON-LINE or a LOCAL
(off-line) condition. When the terminal is on-line (the
keyboard ON-LINE indicator is ON) all characters
typed on the keyboard are sent directly to the computer and messages from the computer are displayed
on the screen. In the LOCAL condition (the keyboard
LOCAL indicator is ON), the terminal is electrically disconnected from the computer; messages are not sent
to or received from the computer; and characters typed
on the keyboard are echoed on the screen directly.

When the new line feature is disabled, the RETURN
key generates only the CR code; an LF code causes the
terminal to perform a line feed only.

NOTE
If double line feeds occur consistently, turn this feature off
since the computer is already performing this function.

PARITY
Parity, when enabled, checks for correct data transmission. If a transmission error occurs, the VT100 can detect it and indicate its presence by placing a
checkerboard character (:::::: ) on the screen in place of
the character with the error. The parity sense feature
determines if the parity is even or odd. When parity is
disabled, no parity bit is transmitted or received.

PARITY SENSE
the parity sense feature defines which of the two
methods of parity checking, odd or even, is being used
by the VT100. If the parity feature is on, the terminal's
parity sense must be matched to the parity the computer is sending. If the parity sense features do not
match, most characters sent to the computer will be
rejected even though the character was received correctly by the VT100. If a parity incompatibility occurs,
the checkerboard character ( :::::: ) will be shown on the
screen in place of the received character.

NOTE
If the parity feature is turned off, the parity sense selection
will be disregarded.

POWER
During the initial installation, the terminal display must
be set to the power line frequency. In the U.S. this is
set to 60 hertz.

RECEIVE SPEED

MARGIN BELL

The receive speed must be set to match the computer
transmit speed. The VT100 is capable of receiving at
anyone of the following preselected speeds: 50, 75,
110,134.5,150,200,300,600,1200,1800,2000,
2400, 3600, 4800, 9600, 19,200 baud.

The margin bell feature is much the same as the bell in
a typewriter. If the cursor is eight characters from the
end of the current line while typing, the VT100 sounds
a tone to a lert the operator.

The receive speed is independent of the transmit
speed; the terminal may receive data at one speed and
transmit data at a different speed.

NEW LINE
The new line feature enables the RETURN key on the
terminal to function like the RETURN key on an electric
typewriter. When the new line feature is enabled,
pressing the RETURN key generates the carriage return (CR) and line feed (LF) codes. When a line feed
code is received, the code is interpreted as a carriage
return and line feed.
1-14

SCREEN BACKGROUND
The screen background feature of the VT100 allows
the operator to determine the background of the
screen. In the normal screen mode, the display contains light characters on a dark background; in the reverse screen mode, the display contains dark
characters on a light background.

SCREEN BRIGHTNESS
Unlike most video terminals, the VT100 does not contain switches or knobs to adjust screen brightness. Instead, the VT100 electronically controls the screen
brightness. This feature eliminates the high failure rate
of mechanical controls and still allows the operator to
select the desired level of brightness for maximum
comfort under varied lighting conditions. This setting
may be saved like any other feature in the terminal.
SCROLL
Scrolling is the upward or downward movement of existing lines on the screen to make room for new lines at
the bottom or top of the screen. It can be performed in
two ways: jump scroll or smooth scroll. In jump scroll
mode, new lines appear on the screen as fast as the
computer sends them to the terminal. At the higher
baud rates, the data is very difficult to read due to the
rapid upward movement of the lines. In smooth scroll
mode, a limit is placed on the speed at which new lines
of data may be sent to the terminal. The upward movement of lines occurs at a smooth steady rate allowing
the data to be read as it appears on the screen.
NOTE
Smooth scroll mode allows a maximum of six lines of data
per second to be added to the screen. The Auto XON/XOFF
feature must be enabled and supported by the host computer to ensure that data is not lost when smooth scroll
mode is enabled.

TABS
Just like a typewriter, the VT100 can jump or tab to
preselected points on a line. These tab stops may be
individually changed, or totally cleared and then reset.

TRANSMIT SPEED
Transmit speed must be set to match the computer
receive speed. The VT100 is capable of transmitting at
anyone of the following preselected transmit speeds:
50,75,110,134.5,150,200,300,600,1200,1800,
2000, 2400, 3600, 4800, 9600, and 19,200 baud.

Transmit speed is independent of receive speed; the
terminal may transmit data at one speed and receive
data at a different speed.

WRAPAROUND
When this feature is enabled, the 81 st or 133rd character (depending upon the line size selected) inserted
on a line is automatically placed in the first character
position of the next line. If the wraparound feature was
not enabled, the 81 st or 133rd character and all following characters would be overwritten into the last
character position of the current line.

ri£l
L.!J (shifted)
The VT100 contains character sets for the U.S. and the
United Kingdom. The difference between the two character sets is one character, the # or £ symbol. When
the standard U.S. character set is selected, the uppercase 3 key on the main keyboard displays the #
character. The £ character is displayed when the U. K.
character set is selected.

PART 4
SELF-TESTING
THE VT100

A self-test mode is built into the VT100 that automatically, or on command, tests
the condition of the terminal should a fault be suspected. The self-test program
checks the following items:
Advanced Video M emory (if option is installed)
Nonvolatile Memory (NVR)
Internal memory
Keyboard
This test is performed automatically whenever the terminal is turned on.

Self-Test Error Codes
There are two broad categories of errors: fatal and nonfatal.
Fatal errors cause the terminal to immediately stop all operations. No intelligible
information is displayed on the screen; however, the screen most likely contains a
random pattern of characters. The only error indication (in addition to the random
characters) is a possible error code displayed on the programmable keyboard
LEOs, L 1-L4; however, no terminal function, including the lighting of LEOs, is
guaranteed if a fatal error is found.
1-15

OPERATOR INFORMATION
Nonfatal errors do not halt the terminal processor. Instead, the terminal is forced to
LOCAL mode and an error code character is displayed in the upper-left corner of
the screen.

There are four types of nonfatal errors:

1.
2.
3.
4.

NOTE
The loopback test is not performed on power-up; it must
be invoked separately with
the proper escape sequence.
See the programmer's section
for further information on this
test.

Advanced Video Option data RAM (AVO)
Nonvolatile data RAM checksum error (NVR)
Keyboard missing or malfunction (KBD)
Data loopback error (Data)

Table 1-3 shows the possible nonfatal error characters that may appear on the
screen and the failure represented by each character.

Table 1-3
Nonfatal Displayed
Error Codes
Displayed
Character

Faulty Module
AVO NVR KBD Data

X
X

6
7
8
9

X
X

>
X

PART 5 -

X
X
X
X

X
X

X
X
X
X

X
X
X
X
X
X
X
X

WHAT TO DO IN THE EVENT OF A PROBLEM

If it appears that there is a problem in the terminal, you should initiate the self-test
procedure. This test will help to determine if the problem lies in your terminal or in
some other part of the computer system.

If the terminal appears to be faulty, refer to Table 1-4. This table describes the
items an operator can check prior to making a service call.

1-16

Table 1-4
Problem Checklist
Symptom

Possible Cause and Corrective Action

VT1 00 will not turn ON when the
power switch is set to ON.

AC power cord is not plugged into wall outlet; plug in cord.
AC power cord is not plugged into the terminal; plug in cord.
Power is not coming from the wall outlet; check outlet with
a known working electrical device (such as a lamp). If no
power. call your electrician.
AC line fuse blown; turn terminal 0 FF and have the fuse
replaced. (See Figure 1-2 for location.)

No keyboard response

Keyboard cable not plugged into monitor; plug in keyboard
cable.
KBD LOCKED indicator on; computer has turned the key
board off. If this condition persists. check with the host computer software people for a possible operating error.
Perform the self-test operation.

Garbled Characters

Transmit and/or receive speeds. parity sense. or parity enable may be wrong; check settings.
Perform the self-test operation outlined.

1-17

CHAPTER 2
Installation, Interface
Information and Specifications

CHAPTER 2
INSTALLATION, INTERFACE
INFORMATION, AND SPECIFICATIONS

SITE CONSIDERATIONS
The design of the VT100 terminal (Figure 2-1) will normally pose few constraints
on selecting a place in which to install the terminal. In most cases, any environment suitable to the terminal operator will be a satisfactory environment in which
to operate the terminal. Extremes of temperature and humidity should be avoided.
A summary of VT100 guaranteed operating conditions is found at the end of this
section.
UNPACKING AND INSTALLATION
The VT100 shipping carton contains the following items:
VT100 monitor
VT100 detached keyboard
VT100 power cord
VT100 SET-UP label
VT100 User's Guide

2-3

INSTALLATION, INTERFACE INFORMATION, AND SPECIFICATIONS

36.8 CM
(14 112 IN.)

. flC

]

8.9 CM

(3 112 IN.)

4.8 CM

~
t:J

c:J

(1_7/8
IN.)
~
_~
__ I _ _ _

L (411.13/8CMIN.) -l

~-----30.5

20.32 CM (8 IN.)

CM (12 I N . ) - - - - - - - . t

....------36.2 CM (14 1/4 I N . ) - - - - - - - . t
. . . . - - - - - - - - - - - - 51.4 -CM (20 1/4 IN.") - - - - - - - - - - - - - '

41.3 CM (161/4IN.)

45.7CM (18 IN.)
"MEASUREMENT TAKEN WITH THE KEYBOARD PLACED FLUSH TO FRONT OF TERMINAL UNDER UNDERCUT.
MA-1991

Figure 2-1
VT100 Terminal Dimensions

2-4

To install the VT100 perform the following steps:
1.

Remove the VT100 from the shipping carton and place it in the desired
work area.

Place the keyboard in front of the terminal and plug the keyboard coiled
cord into the keyboard receptacle located on the rear of the terminal
(Figure 2-1).

Verify that the power selector switch shows the correct wall outlet
voltage (115 V is standard in the U.S.) and the power switch is off.

Connect the power cord to the power cord receptacle on the rear of the
terminal and plug the other end of the power cord into a nearby wall
outlet.

Connect the communications cable to the appropriate communications
receptacle.

Turn the power switch on. The terminal will now automatically perform
the power-up self test and either the ON LINE or LOCAL light located
on the keyboard will be turned on. After approximately one minute the
cursor will be visible in the upper-left corner of the screen

Set the desired SET-UP features outlined in the operator's section of
this manual.

Once the installation setup procedure is complete, record the SET-UP
features selected on the VT100 SET-UP label and attach the label to
the underside of the keyboard.
CAPTIVE
SCREWS (4)

ACCESS
COVER

1
6
~__~~~~~mnmmr-

EIA
COMMUNICATIONS
CONNECTOR
EXTERNAL
VIDEO
COMMUNICATIONS

MAIN FUSE
POWER SWITCH

g
-I

DDD

MODEL + SERIAL
NUMBER LABEL

~~1-~~==~~--~~------~~-~i'~-~-=-=~'
KEYBOARD
CONNECTOR

POWER
SELECTOR
SWITCH

POWER CORD
CONNECTOR

OPTIONAL 20mA
Figure 2-2

vn 00 Rear View

COMMUNICATION
CONNECTOR

MA-1987

2-5

INSTALLATION, INTERFACE INFORMATION, AND SPECIFICATIONS
USER MAINTENANCE
The keyboard keys are the only moving parts of the terminal and require no preventive maintenance by the owner. The VT100 surfaces may be cleaned with soap
and water or any mild detergent. Cleaners with solvents should not be used.
The VT100 packaging is not meant to be weatherproof; there are several openings
in the case through which liquids, coins, paper clips, and other objects can fall.
Such objects would disturb the electronic operation of the terminal if they came
into contact with the circuitry. For this reason, avoid putting drinks and metal
objects on the top of the terminal, or using excessive water to clean the terminal.
Rubbing the keys with a dry or barely moist cloth should suffice to clean them. Do
not remove the keycaps to clean them more thoroughly; damage may result to the
switch contacts if they are replaced incorrectly.
Keep the ventilation slots clear. Blocking these slots by placing objects on top of or
under the VT100 may cause the terminal to overheat.
INTERFACE
INFORMATION
EIA Interface

The basic VT100 operates on full duplex, asynchronous communication lines. The
terminal interfaces to the line with a 25-pin connector mounted on the back of the
terminal which meets the requirements of EIA specification RS232-C. Table 2-1
summarizes the EIA connector signals; the following paragraphs explain each signal as used in the basic VT100.

Table 2-1
EIA Connector Signals
Pin
Number

2
3
4
5

Protective ground
Transmitted data
Received data
Request to send
Clear to send

Data set ready
Signal ground (common return)
Carrier detect
(not used)
(not used)

11
12
13
14
15

Same as pin 19
(Secondary carrier detect) speed indicator
(not used)
(not used)
Transmit clock

(not used)
Receive clock
(not used)
(Secondary request to send) speed select
Data terminal ready

8
9

17
18
19

20
21

22
23
24

25
2-6

Description

(not used)
Ring indicator
Same as pin 19
(not used)
(not used)

Protective Ground - Pin 1
This conductor is electrica lIy bonded to the VT 100
chassis. Use of this conductor for reference potential
purposes is not allowed.
Transmitted Data (from VT100) - Pin 2
The VT100 transmits serially encoded characters and
break signals on this circuit, which is held in the mark
state when neither characters nor break signals are
being transmitted.
Received Data (to VT100) - Pin 3
The VT100 receives serially encoded characters generated by the user's equipment on this circuit.
Request to Send (from VT100) - Pin 4
Asserted at all times when terminal is powered up.
Clear to Send (to VT100) - Pin 5
Ignored at all times.
Data Set Ready (to VT100) - Pin 6
Ignored at all times.
Signal Ground - Pin 7
This conductor establishes the common ground reference potential for all voltages on the interface. It is
permanently connected to the VT100 chassis.

Carrier Detect (to VT100) - Pin 8
Ignored at all times.

Speed Select (from VT100) - Pins 11, 19, and 23
This signal is alternately called Secondary Request to
Send. The basic VT 100 maintains this line in the unasserted state at all times.

Speed Indicator (to VT100) - Pin 12
This signal, alternately called Secondary Carrier Detect, is ignored at all times.

Transmission Clock (to VT100) - Pin 15
Ignored at all times.

Receive Clock (to VT100) - Pin 17
Ignored at all times.

Data Terminal Ready (from VT100) - PI N 20
Data Terminal Ready is asserted at all times.

Ring Indicator (to VT100) - Pin 22
Ignored at all ti meso

Electrical Characteristics
VT100 Output Voltages - On all signals designated "from VT100," the mark or
unasserted state is -6.0 V to -12.0 V; the space or asserted state is +6.0 V to
+12.0 V.

VT100 Input Voltages - On signals designated "to VT100," -25.0 V to +0.75 V
or an open circuit i$ interpreted as a mark or unasserted state, and +25.0 V to
+2.25 V is interpreted as a space or asserted state. Voltages greater in magnitude
than ±25 V are not allowed. These levels are compatible with EIA STD RS232-C
and CCITI Recommendation V.28.

Optional 20 mA
Current Loop Interface

In most current loop applications, the VT100 will be connected in a passive configuration - that is, current is supplied to the VT100. In this mode, the transmitter
and receiver are both passive, both optically isolated, and the transmitter goes to
the mark state when power is turned off.
Conversion from active to passive (or vice versa) requires moving a slide switch.
In active mode either the transmitter or the receiver or both may be connected so
that the VT100 sources the 20 mA of current. In active mode isolation is not
present and the transmitter will go to the space state when power to the VT100 is
turned off.
2-7

INSTALLATION, INTERFACE INFORMATION, AND SPECIFICATIONS
Figure 2-3 shows the 20 rnA current loop interface connector mounted to the
access cover and the individual pin assignment.
Electrical Characteristics
The electrical characteristics of the 20 rnA current loop interface are shown below:

Transmitter

Open circuit voltage
Voltage drop marking
Spacing current
Marking current

Receiver
Voltage drop marking
Spacing current
Marking current

Min

Max

5.0V

20 rnA

50V
4.0V
2.0mA
50 rnA

15 rnA

2.5 V
3.0 rnA
50mA

TERMINAL
ACCESS
COVER

PIN ASSIGNMENTS
1 - .TEST NEGATIVE
2 - TRANSMIT 3 - RECEIVE 5 - TRANSMIT +
7 - RECEIVE +
8 - PROTECTIVE GROUND

o
Figure 2-3
20 mA Current Loop Interface

2-8

20mA CU RRENT
LOOP CONNECTOR

00000000

123

MA-1992

External
Video Connections

In addition to the above specifications for passive operation, active mode will place
the transmitter or receiver in series with a source of 17 V ±5 percent and 660
ohms.
In addition to the EIA interface, the VT100 is also capable of easily interfacing to
external video devices. The video devices may act either as a slave to the VT100
when connected to the composite video output or provide synchronized video to
the VT100 video section when connected to the video input. The external video
connectors are the two female BNC connectors located on the back of the terminal
just below the EIA connector. The upper connector, J8, is the video input while the
lower connector, J9, is the video output.
Composite Video Output (J9)
The composite video output provides RS 1 70-like output (see note) generated by
combining the video signal with a composite sync signal. The output has the following nominal characteristics. (Refer to Figure 2-4.)

EVEN FIELD:

VERTICAL BLANKING INTERVAL

LAST DISPLAYED SCAN OF

60 Hz NON-INT = 22 SCANS}
60 Hz INT
=22 SCANS
_ _ _~

14-----------------{ 50 Hz NON-INT = 75 SCANS
50 Hz INT

{

.~~~

:\r\

TIME_

FIRST OF 240 DISPLAYED
SCANS IN EVEN FIELD

= 74 SCANS

60 Hz NON-INT = 2 SCANS
60 Hz INT
= 2 SCANS
50 Hz NON-INT = 25 SCANS
50 Hz INT
= 24 SCANS

I
:

r--

START OF
EVEN FIELD

H PE RIOO

6356 " ' ± 50 m

ODD FIELD:
LAST DISPLAYED .SCAN OF
EVEN FIELD

: VERTICAL BLANKING INTERVAL

{60 Hz INT

14------1--------------- 50 Hz INT
60HZINT
{ 50 Hz INT

1.0 V

= 2 112 SCANS
= 24 112 SCANS

!\r\

TIME-

START OF
ODD FIELD

H PERIOD

6356., ± 50 NS

NOTES:
IN NON-INTERLACED OPERATION THE
EVEN FIELD IS REPEATED CONTINUOUSLY. AND THE ODD FIELD IS NOT
USED.

-1 F

IN THE INTERLACED OPERATION THE
EVEN FIELD ALTERNATES WITH THE ODD
FIELD.

H BLANK {11.84/LS ± 50 ns 180 COLUMN
12.3 4 /Ls ± 50 ns 1132 COLUMN

BRIGHT = 1 . 0 0 V _ §
NORMAL = .79 V DIM = .64VBLACK = .29 V SYNC =O.OOVOLTFRONT PORCH = 1.54/Ls ± 50ns
H SYNC = 4.71 /LS ± 50 ns

•

1---------1

ALL FIELDS CONTAIN 240 DISPLAYED
SCANS.

u---'f

~Q = 2.33/Ls ± 50ns -./ j..

I'---~n
-...J

j..-v SYNC = 27.28 /.lS

± 200 ns

H PERIOD = 63.56 /LS ± 50 ns

Figure 2-4
Composite Video Output

2-9

INSTALLATION, INTERFACE INFORMATION, AND SPECIFICATIONS
1.
2.
3.
4.
NOTE
The use of decoupling is not in
strict agreement with RS170.
To agree with RS170 the output load requires a 10 f..LF capacitor in series with the
output. Failing to do so, the 2
mA dc short circuit current requirement is violated. This
presents no problem with
most monitors which are in
fact ac-coupled.

NOTE
The external video source
must be synchronized to the
VT100; it may do this by referencing the composite sync
on the composite video output.

Output impedance = 75 ohms, dc-coupled
Sync level = 0 V
Black level = approximately 0.3 V when loaded with 75 ohms
White level = approximately 1.0 V with a 75 ohm load
The composite sync waveform conforms to EIA RS 170 standards. The
vertical interval is composed of six equalizing pulses, six vertical sync
pulses, and six more equalizing pulses. The timing is as follows:
Equalizing pulse width
Vertical pulse width
Horizontal pulse width
Horizontal blank width

2.33 f..LS ±50 ns

= 27.28 f..LS ±200 ns

= 4.7 1 f..Ls ± 50 ns
=

11.84 f..LS ±50 ns/80 column mode

= 12.34 f..LS ±50 ns/132 column mode

Front Porch

1.54 f..LS ±50 ns

Video Input (J8)
An analog signal applied to the video input will be "ORed" with the internal video
signal in such a way that the beam intensity at any point on the screen will correspond to the intensity of that signal which would tend to make the beam brighter
at that point. This input has the following nominal characteristics.
1.
2.
3.
4.

Input impedance = 75 ohms, dc-coupled
Black level = 0 V
White level = 1.0 V
Maximum continuous input = ±2.0 V

VT100 SPECIFICATIONS
Dimensions

Monitor

Height: 36.83 cm (14.5 inch)
Width: 45.72 cm (18 inch)
Depth: 36.20 cm (14.25 inch)

Keyboard

Height: 8.89 cm (3.5 inch)
Width: 45.72 cm (18 inch)
Depth: 20.32 cm (8 inch)
Minimum table depth: 51.4 cm (20.25 inch)

Monitor
Keyboard
Shipping Weight

13.6 kg (30 Ibs)
2.0 kg (4.5 Ibs)
18.6 kg (41 Ibs)

Operating

Temperature: 10 0 to 40 0 C (50 0 to 104 0 F)
Relative humidity: 10% to 90%
Maximum wet bulb: 28 0 C (82 0 F)
Minimum dew point: 2 0 C (36 0 F)
Altitude: 2.4 Km (8,000 ft)

Non-Operating

Temperature: -40 0 to 66 0 C (-40 0 to 151 0 F)
Relative humidity: 0 to 95%
Altitude: 9.1 km (30,000 ft)

Line Voltage

90-128 V RMS single phase, 2 wire
180-256 V RMS single phase, 2 wire
(switch-selectable)
47-63 Hz

Weight

Environment

Power

Line Frequency
2-10

Current
Input Power
Current limiting
Power cord

3.0 A RMS maximum at 115 V RMS
1.5 A RMS maximum at 230 V RMS
250 VA apparent 150 W maximum
3 A normal blow fuse
detachable. 3 prong. 1.9 m (6 ft)

Display

CRT
Format
Character
Character size

Active Display Size
Character Set
Cursor type

12 inch diagonal measure. P4 phosphor
24 lines X 80 characters or 14 lines X 132 characters (selectable)
7 X 9 dot matrix with descenders
3.35 mm X 2.0 mm (0.132 inch X 0.078 inch) in
80 column mode
3.35 mm X 1.3 mm (0.132 inch X 0.051 inch) in
132 column mode
202 mm X 115 mm (8 inch x 4.5 inch)
96 character displayable ASCII subset (upperand lowercase. numeric and punctuation)
Keyboard-selectable. blinking block character or
blinking underline.

Keyboard

General

83-key detachable unit with a 1.9 m (6 ft) coiled
cord attached

Key Layout

65-key arrangement and sculpturing similar to
standard typewriter keyboard with an 18-key
auxiliary keypad.

Auxiliary Keyboard

18-key numeric pad with period. comma. minus.
enter. and four general purpose function keys

Visual Indicators

Seven LEOs; three LEOs dedicated to ON LINE.
LOCAL and KBD LOCKED. four LEOs user-programmable.

Audible Signals

Key-click: sound simulates typewriter bell:
1) sounds upon receipt of BEL code; 2) sounds
eight characters from right margin (keyboard-selectable). Multiple bell: sounds upon detection of
error in SET-UP save or recall operation.

Type
Speeds

EIA
Full duplex: 50.75. 110 (two stop bits). 134.5.
150.200.300.600.1200.1800.2000.2400.
3600. 4800. 9600. 19.200
ASCII
Asynchronous
7 or 8 bits; keyboard-selectable. (Note: if 8-bit
character is selected. 8th bit is always space.)
Even. odd. or none - keyboard-selectable
Keyboard-selectable via automatic generation of
XON and XOFF control codes.

Communication

Code
Character Format
Character Size
Parity
Synchronization

2-11

INSTALLATION, INTERFACE INFORMATION, AND SPECIFICATIONS
HOW TO ORDER HARDWARE DOCUMENTATION
The following VT100 DECscope Video Terminal hardware manuals can be purchased from DIGITAL's Accessory and Supplies Group.
Part No.
EK-VT100-UG
EK-VT100-J1
EK-VT100-TM
EK-VT100-IP
MP-00663

Title
VT100 User Guide
VT100 Mini Maintenance Manual
VT100 Technical Manual
VT100 Illustrated Parts Breakdown (I PB)
VT100 Print Set

All purchase orders for hardware manuals should be forwarded to:
Digital Equipment Corporation
Cotton Road
Nashua, N.H. 03060
Accessory and Supplies Group (POB6)
Purchase orders must show shipping and billing addresses and state whether a
partial shipment will be accepted.
All correspondence and invoicing inquiries should be directed to the above address.

2-12

CHAPTER 3
Programmer Information .

VT100

r---------'
I

I
I
I

I
I

1
I
I

I
...-:-1_ _ _---1

RECEIVER

I
I

I
L_

COMPUTER
(HOST)

r-TI-------

TRANSMITTER

_ ______

'---y--Figure 3-1
Terminal Data Flow

3-2

COMMUNICATION
LINES

MA-1994

CHAPTER 3
PROGRAMMER's INFORMATION

The VT100 terminal normally performs a two-part function. It is an input device to
a computer - information entered through the keyboard is sent to the computer. It
is simultaneously an output device for the computer - that is, data coming in from
the computer is displayed on the video screen. Figure 3-1 shows the data flow.
This section of the user's manual discusses data flow between the VT100 and the
host. Included are the codes generated by the keyboard; the transmission protocol
followed by the terminal; and the actions and reactions of the terminal to control
codes and escape sequences, in both ANSI and VT52 modes of operation.
The VT100 is an upward and downward software compatible terminal; that is,
previous DEC video terminals have DEC private standards for escape sequences.
The American Standards Institute (ANSI) has since standardized escape sequences in terminals.
NOTE
The ANSI standards aI/ow the
manufacturer flexibility in implementing each function.
This manual describes how
the VT100 will respond to the
implemented ANSI control
functions.

The VT100 is compatible with both the previous DEC standard and the ANSI
standards. Customers may use existing DEC software designed around the VT52
or new VT100 software. The VT100 has a "VT52 compatible" mode in which the
VT100 responds to escape sequences like a VT52. In this mode, most of the new
VT100 features cannot be used.

Throughout this section of the manual references will be made to "VT52 mode" or
"ANSI mode." These two terms are used to indicate the VT1 OO's software compatibility. All new software should be designed around the VT100 "ANSI mode."
Future DIGITAL video terminals will not necessarily be committed to VT52 compatibility.
3-3

PROGRAMMER'S INFORMATION
THE KEYBOARD
The VT100 uses a keyboard with a key arrangement similar to an ordinary office
typewriter. as shown in Figure 3-2. In addition to the standard typewriter keys the
VT100 keyboard has additional keys and indicators used to generate escape and
control sequences. cursor control commands. and to show the current terminal
status.

ET-UP

0 0 0 0

ONONE LOLKBD8CKED
SETI
CLEAR ALL
LlNEI
SETUP
TOGGLE
CLEAR TAB TABS
LOCAL
AlB
110

TRANSMIT RECEIVE
SPEED
SPEED

801132
COLUMNS

RESET

[!][!]EJEJ
T

[JFl [JF2 [JF3 [JF4

Figure 3-2

vn 00 Keyboard

LE D Indicators
The keyboard has seven light emitting diodes (LEOs) of which two are committed
to the complementary ON- LIN E/LOCAL function. The power on condition is implicitly shown by one of the two LEOs being on; that is. if the keyboard is connected
and power is on. one of these LEOs will be on.

A third LEO indicates a "keyboard locked" condition. In this condition the keyboard
has been "turned off" automatically by the terminal due to a full buffer or by the
host through the transmission of an XOFF to the terminal.

The four remaining LEOs are programmable and can be assigned any meaning for
specific applications. The code sequences to turn these LEOs on or off are discussed later in this chapter.

SET-UP Key
The SET-UP key is at the upper-left corner of the main key array. Operations
performed in SET-UP mode can be stored in nonvolatile memory (NVR) so that
turning the terminal power off does not. by itself. alter the terminal configuration.

The procedures to change the SET-UP features are provided in the operator's
information section of this manual. Those SET-UP features which may be modified
by the host are listed in Table 3-1 and described in detail under the escape sequences.

Keyboard Operation
The operator uses the keyboard to transmit codes to the host. Some keys transmit
one or more codes to the host immediately when typed. Other keys such as CTRL
3-4

and SHIFT do not transmit codes when typed, but modify the codes transmitted by
other keys. The code-transmitting keys cause the terminal to make a clicking
sound to verify to the operator that the keystroke has been processed by the
terminal. If two code-transmitting keys are pressed together, two codes will be
transmitted according to the order in which the keys were typed. The terminal will
not wait for the keys to be lifted, but will transmit both codes as soon as possible
after the keys are first typed. If three such keys are pressed simultaneously, the
codes for the first two keys are transmitted immediately; the code for the third will
be transmitted when one of the first two keys is lifted.

Table 3-1
SET-UP Features and
Machine States

SET-UP Feature
or Machine State

Changeable
from Host
Computer*

Saved in NVR
and Changeable
in SET-UP

Alternate keypad mode
ANSI/VT52
Auto Repeat
AUTO XON XOFF
Bits per character
Characters per line
Cursor
Cursor key mode
Graphics mode
Interlace
New Line
Keyclick
Margin bell
Origin mode
Parity
Parity sense
Power
Receive speed
Screen
Scroll
Tabs
Transmit speed
Wraparound

Yes (DECKPAM/DECKPNM)
Yes (DECANM)
Yes (DECARM)
No
No
Yes (DECCOLM)
No
Yes (DECCKM)
Yes (DECGON/DECGOFF)
Yes (DECINLM)
Yes (LNM)
No
No
Yes (DECOM)
No
No
No
No
Yes (DECSCNM)
Yes (DECSCLM)
Yes (HTS/TBC)
No
Yes (DECAWM)

No
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes

Yes

#
3

£
(shifted)

• The appropriate control or escape sequence mnemonic is indicated in parentheses.

Alphabetic Keys - The VT100 will transmit the lowercase code unless either or
both of the SH I FT keys are down, or unless the CAPS LOCK key is down. Pressing
the CAPS LOCK key will lock only the 26 alphabetic keys in the shifted (uppercase) mode. Table 3-2 shows the codes generated by the alphabetic keys.

Nonalphabetic Keys - Each of the nonalphabetic keys can be used to generate
two different codes. One code will be generated if neither SH I FT key is pressed.
The other code will be generated if either or both of the SHIFT keys are down.
Unlike the SHIFT LOCK key of a typewriter, the CAPS LOCK key does not affect
these keys; it affects only the alphabetic keys. Table 3-3 shows the nonalphabetic
keys and the codes they generate.
3-5

PROGRAMMER'S INFORMATION
Table 3-2
Alphabetic Key Codes
Key
A

B
C
D

E
F

H
I

J
K
L

M
N

0
p
Q

S
T

U
V

W
X
y
Z

Uppercase
Code (octal)

Lowercase
Code (octal)

101
102
103
104
105
106
107
110
111
112
113
114
115
116
117
120
121
122
123
124
125
126
127
130
131
132

141
142
143
144
145
146
147
150
151
152
153
154
155
156
157
160
161
162
163
164
165
166
167
170
171
172

Table 3-3
Nonalphabetic Key Codes
Neither SHIFT
Lowercase Key Down
Character (Octal)

1
2
3
4
5
6
7
8
9

\
....

3-6

061
062
063
064
065
066
067
070
071
060
055
075
133
073
047
054
056
057
134
140
135

Uppercase
Character

# or£
$
%
1\
&

+
{

<
>

Either or Both
SHIFT Keys Down
(Octal)

041
100
043
044
045
136
046
052
050
051
137
053
173
072
042
074
076
077
174
176
175

Function Keys - There are several keys on the keyboard which transmit control
codes. Control codes do not produce displayable characters but are codes for
functions. If these codes are received by the terminal. the VT100 will perform the
associated function as shown in Table 3-4.

Table 3-4
Function Key Codes
Key

Octal Value of Code
Sent or Received by VT100

Action The Terminal Would
Take if Host Sent That Code

RETURN*
LINE FEED
BACK SPACE
TAB
SPACE BAR

015
012
010
011
040

ESC

033

Delete

177

Carriage return function
Line Feed
Backspace function
Tab function
Deposit a space on the screen erasing what was
there before.
The initial delimiter of an escape sequence - interpret the following character string from the host
as a command. rather than displaying it.
Ignored by the VT100

• The RETURN key can be redefined so that it issues 015 8 • 012 8 • (carriage return - line feed). The New Line
feature in SET-UP mode provides this capability.

NO SCROLL Key - When the NO SCROLL key is pressed it generates a single
XOFF code and inhibits further scrolling. When pressed again the same key generates XON. In practice, if the software recognizes XOFF, the host will stop transmitting until the NO SCROLL key is pressed again to allow scrolling. If the
XOFF/XON feature is disabled (SET-UP function) the NO SCROLL key causes no
action.

BR EA K Key - Typing the BR EAK key causes the transmission line to be forced to
its space state for 0.2333 seconds ± 10 percent. If either SH I FT key is down, the
time is increased to 3.5 seconds ± 10 percent.
The SH I FT and BREAK keys typed together provide the long-break-disconnect
function. Used with properly configured modems with RS232-C levels, it will
cause both the local and remote data sets to disconnect. For modems that are
connected via the 20 rnA loop, issuing the long space may disconnect the remote
data set only.
The CONTROL and BREAK keys typed together cause the transmission of the
answerback message.
The BREAK key does not function when the VT100 is in LOCAL mode.

Auto Repeating - All keys will auto repeat except: SET-UP, ESC, NO SCROLL
TAB, RETURN, and any key pressed with CTRL. Auto repeating may be disabled
(SET-UP function). Auto repeating works as follows: when a key is typed, its
code(s) is sent once, immediately. If the key is held down for more than 1/2
second, the code(s) will be sent repeatedly at a rate of approximately 30 Hz (less if
low transmit baud rates are used) until the key is released.
3-7

PROGRAMMER'S INFORMATION
CTRL (Control) Key - The CTRL key is used in conjunction with other keys on the
keyboard to generate control codes. If the CTRL key is held down when any of the
keys in Table 3-5 are typed, the code actually transmitted is in the range

0008-0378.
Table 3-5
Control Codes Generated
Key Pressed with
CTR L key down
(shifted or
(unshifted)

Space Bar
A
B
C
D
E
F
G
H
I
J

K
L
M

N
a
P

R
S
T
U
V
W

X
Y
Z
[

\
J

Octal Code
Transmitted

Function
Mnemonic

000
001
002
003
004
005
006
007
010
011
012
013
014
015
016
017
020
021
022
023
024
025
026
027
030
031
032
033
034
035
036
037

NUL
SOH
STX
ETX
EaT
ENO
ACK
BELL
BS
HT
LF
VT
FF
CR
SO
SI
DLE
DC1 or XON
DC2
DC3 or XOFF
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US

Cursor Control Keys - The keyboard also contains four keys labeled with arrows
in each of four directions. These keys transmit escape sequences. If the host echoes these escape sequences back to the terminal, the cursor will move one character up, down, right, or left. Table 3-6 shows the escape sequences generated by
each key.
Table 3-6
Cursor Control Key Codes

3-8

Cursor Key
(arrow)

VT52
Mode

ANSI Mode and Cursor
Key Mode Reset

ANSI Mode and Cursor
Key Mode Set

Up
Down
Right
Left

ESCA
ESC B
ESCC
ESC D

ESC[A
ESC [B
ESC [C
ESC [D

ESCOA
ESC a B
ESCOC
ESCO D

Auxiliary Keypad - The keys on the auxiliary keypad normally transmit the codes
for the numerals. decimal point. minus sign. and comma. In addition. the key
labeled ENTER transmits the same code as the RETURN key. The host cannot tell
if these keys were typed on the auxiliary keypad as opposed to the corresponding
keys on the main keyboard. Therefore. software which requires considerable numeric data entry need not be rewritten to use the keypad.
However. if software must be able to distinguish between pressing a key on the
auxiliary keypad and pressing the corresponding key on the main keyboard for
instance. the host can give the terminal a command to place it in keypad application mode. In keypad application mode all keys on the auxiliary keypad are
defined to give escape sequences which may be used by the host as user-defined
functions.

Table 3-7
VT52 Mode
Auxiliary Keypad Codes

The codes sent by the auxiliary keypad for the four combinations of the
VT52/ANSI mode and keypad numeric/application mode are shown in Tables 3-7
and 3-8. None of the keys are affected by pressing the SHIFT. CAPS LOCK. or
CONTROL keys.
Key

Keypad
Numeric Mode

0
1
2
3
4
5
6
7
8
9

ENTER

PF1
PF2
PF3
PF4
Table 3-8
ANSI Mode
Auxiliary Keypad Codes

Keypad
Numeric Mode

1
2
3
4
5

3
4

5
6
7

8
9

NOTE
In ANSI mode, if the codes
are echoed back to the
VT100, or if the terminal is in
local mode, the last character
of the sequence will be displayed on the screen; e.g.,
PF1 will display a liP.

ESC? p
ESC? q
ESC? r
ESC? s
ESC? t
ESC? u
ESC? v
ESC ?w
ESC? x
ESC? y
ESC? m
ESC? I
ESC? n
Same as RETURN key ESC? M
ESC P
ESC P
ESCQ
ESCQ
ESCR
ESC R
ESC S
ESCS

Key

ENTER

PF1
PF2
PF3
PF4

Keypad
Application Mode

ESCO p
ESCO q
ESC 0 r
ESC 0 s
ESC 0 t
ESCO u
6
ESCO v
7
ESCOw
ESCO x
8
ESC Oy
9
ESCO m
ESC 0 I
ESC 0 n
Same as RETURN key ESCO M
ESC 0 P
ESC 0 P
ESCOQ
ESCO Q
ESCO R
ESCO R
ESCO S
ESCO S

3-9

PROGRAMMER'S INFORMATION
Special Graphics Characters
If the Special Graphics set is selected, the graphics for ASCII codes 1378 through
176 8 will be replaced according to Table 3-9. (See the SCS escape sequence.)
Table 3-9
Special Graphics Characters
Octal
Code

Graphic With
US or UK Set

Graphic with
"Special Graphics" Set

137

Blank

140
141

." Check board (error indicator)

If HT (horizontal tab)

142

143

FF FF (form feed)

144

~ CR (carriage return)

145

146
147

150

Degree symbol

± Plus/minus ±
~ N L (new line)

'f VT (vertical tab)

152

Lower-right corner

153

Upper-right corner

154

Upper-left corner

155

Lower-left corner

156

+ Crossing lines

157

160

161

Horizontal line - Scan 5

Horizontal line - Scan 7

I-

Horizontal line - Scan 9
Left HI"
Right'T'

162
163

Horizontal line - Scan 1

164

3-10

~ LF (line feed)
o

151

COMMUNICATION
PROTOCOLS

Diamond

Horizontal line - Scan 3

165

-I

166

Bottom "I"

167

Top'T'
Vertical Bar

170

171

Less than or equal to

172

Greater than or equal to

173

TI'

Pi (mathematical)

174

Not equal to

175

£ UK pound sign

Centered dot

NOTE 1:

Codes 152 8 -1 56 8 • 161 8 • and 1648 -170 8 are used to draw rectangular
grids; each piece of this line drawing set is contiguous with others so that the
lines formed are unbroken.

NOTE 2:

Codes 157 8 -163 8 giver better vertical resolution than dashes and underlines
when drawing graphs; using these segments 120 X 132 resolution may be
obtained in 132 column mode with the Advanced Video Option installed.

Full Duplex
The terminal can operate at transmission speeds up to 19,200 baud. However, the
terminal may not be able to keep up with incoming data. The terminal stores
incoming characters in a 64 character buffer and processes them on a first-in/firstout basis. When the content of the buffer reaches 48 characters, the terminal will
transmit 023 8 (XOFF or DC3). On this signal the host should suspend its transmission to the terminal. Eventually, if the host stops transmitting, the terminal will
deplete the buffer. When 16 characters remain in the buffer the terminal will
transmit 0218 (XON or DC1) to signal the host that it may resume transmission.

If the host fails to respond to an XOFF from the terminal in a timely manner. the
buffer will continue to fill. When the 64-character capacity of the buffer is exceeded. a condition occurs called "buffer overflow." To determine if the buffer will
overflow use the following formulas:
No. of characters to overflow

= 16 - [3 X (receiver speed/transmit speed) I

Time to respond to XOFF

No. of characters to overflow X
(bits per character +
parity bit + 2)/receiver speed

Example 1:
The VT100 is transmitting 8-bit characters with no parity at 1200 baud and receiving at 1200 baud. The terminal has just sent an XOFF which the host must
respond to within 0.1083 second to avoid a buffer overflow.
No. of characters to overflow

= 16 - [ (3 X 1200/1200) I = 13 characters

Time to respond to XOFF

= 13 X (8+0+2)/1200 = 0.1083 second

Example 2:
The VT100 is transmitting 7-bit characters with parity at 300 baud and receiving
at 1200 baud. The terminal has just sent an XOFF which the host must respond to
within 0.0333 second to avoid a buffer overflow.
No. of characters to overflow

= 16 - [ (3 X 1200/300) I = 4 characters

Time to respond to XOFF

4 X (7 + 1 +2)/1200 = 0.0333 second

If the buffer overflows. the VT100 will begin to discard incoming characters and
the error character will be displayed.
Software which does not support receipt of the XOFF/XON signals from the terminal can still use the VT100 provided the software never sends the ESC code to the
terminal. the baud rate is limited to 4800 or less. and the software does not use
smooth scrolling or split screen features.
Two of the terminal functions. Reset and Self-Test. reinitialize the terminal and
erase the buffer. This means that if characters are received subsequent to the
commands to perform these two functions and the characters are placed in the
buffer. the character would be destroyed without being processed.
To compensate for this. the host may act in one of two ways:
1.

Immediately after sending the terminal the commands to perform either
the Reset or Self-Test functions. the host may act as if it had received
XOFF from the terminal. thus sending no more characters until it receives XON. The terminal will transmit XON only after it completes the
specified operation and the XOFF/XON feature is enabled.

When the first method cannot be implemented. a delay of no less than
10 seconds may be used to allow the terminal time to complete the
invoked function. This method. however. does not guarantee against
the loss of data when an invoked function has detected an error; and
while this delay is currently adequate. future options may require a
change in the time delay.
3-11

PROGRAMMER'S INFORMATION
The XOFF/XON synchronization scheme has an advantage over requiring the host
to insert delays or filler characters in its data stream. Requiring a minimum of
software support, XON/XOFF ensures that every character or command sent to
the VT100 will be processed in correct order. It frees interface programs from all
timing considerations and results in more reliable operation.
In addition to the buffer-filling condition, there are two other means of transmitting
XOFF and XON; the NO SCROLL key, and Control S/Control Q. If XOFF mode is
enabled, the VT100 will coordinate these three sources of XOFF and XON so that
the desired effect occurs. For example, if the buffer-filling condition has caused an
XOFF to be sent, and then the operator types the NO SCRQLL key, a second XOFF
is not sent. Instead of sending an XON when the buffer empties, the VT100 waits
until the operator types the NO SCROLL key again before sending XON.
Also, entering SET-UP mode causes the VT100 to temporarily stop taking characters from the buffer. An XOFF will be sent if the buffer becomes nearly full.
Use of Control S and Control Q will also be synchronized with the NO SCROLL
key.
If the XOFF feature is disabled, the buffer-filling condition will not send an XOFF,
the NO SCROLL key is disabled, and Control S and Control Q will be transmitted
as typed.
The VT100 also recognizes received XOFF and XON. Receipt of XOFF will inhibit
the VT100 from transmitting any codes except XOFF and XON. From three to
seven keystrokes on the keyboard will be stored in a keyboard buffer (some keys
transmit two or three codes, e.g., cursor controls). If the keyboard buffer overflows,
keyclicks will stop and the KBD LOCKED LED will come on. Transmission resumes
upon receipt of XON.
If the user transmits an XOFF to the host (by Control S or NO SCROLL), the host
should not echo any further type-in until the user types XON. This places the
burden of not overloading the host's output buffer on the user.
Entering and exiting SET -U P clears the transmit and keyboard locked modes.

TERMINAL
CONTROL
COMMANDS

The VT100 has many control commands which cause it to take action other than
displaying a character on the screen. In this way, the host can command the
terminal to move the cursor, .change modes, ring the bell, etc. The following paragraphs discuss the terminal control commands.

Control Characters
Control characters have values of 0008 - 0378, and 1778. The control characters
recognized by the VT100 are shown in Table 3-10. All other control codes cause
no action to be taken.
Table 3-10
Control Characters

3-12

Control
Character

Octal
Code

Action Taken

NUL

000

Ignored on input (not stored in input buffer; see full duplex protocol).

ENQ

005

Transmit answerback message.

BEL

007

Sound bell tone from keyboard.

Table 3-10
Control Characters
(Cont)
Control
Character

Octal
Code

010

Move the cursor to the left one character position. unless it is at the
left margin. in which case no action occurs.

011

Move the cursor to the next tab stop. or to the right margin if no
further tab stops are present on the line.

012

This code causes a line feed or a new line operation. (See new line
mode.)

013

Interpreted as LF.

014

Interpreted as LF.

015

Move cursor to left margin on the current line.

016

Select G 1 character set. as selected by "ESC)" sequence.

017

Select GO character set. as selected by "ESC(" sequence.

XON

021

Causes terminal to resume transmission.

XOFF

023

Causes terminal to stop transmitting all codes except XOFF and
XON.

CAN

030

If sent during an escape or control sequence. the sequence is immediately terminated and not executed. It also causes the error
character to be displayed.

SUB

032

Interpreted as CAN.

ESC

033

Introduces an escape sequence.

DEL

177

Ignored on input (not stored in input buffer).

Action Taken

Escape Sequences
Table 3-11 provides a summary of the VT100 escape sequences.
Table 3-11
VT100 Escape
Sequences Summary

VT52 Compatible Mode
Cursor Up
Cursor Down
Cursor Right
Cursor Left
Select Special Graphics character set
Select ASCII character set
Cursor to home
Reverse I ine feed
Erase to end of screen
Erase to end of line
Direct cursor address
Identify
Enter alternate keypad mode
Exit alternate keypad mode
Graphics processor on
Graphics processor off
Enter ANSI mode
NOTE 1:

ESCA
ESC B
ESC C
ESC D
ESC F
ESCG
ESC H
ESC I
ESCJ
ESC K
ESC Vic (see note 1)
ESC Z (see note 2)
ESC =
ESC>
ESC 1 (see note 3)
ESC 2 (see note 3)
ESC <

Line and column numbers for direct cursor address are single
character codes whose values are the desired number plus 37 8 .
Line and column numbers start at 1.

NOTE 2:

Response to ESC Z is ESC / Z

NOTE 3:

Ignored if no graphics processor option is installed in the
VT100.

3-13

PROGRAMMER'S INFORMATION
ANSI Compatible Mode

NOTE
Pn refers to a decimal parameter expressed as a string of
ASCII digits. Multiple parameters are separated by the
semicolon character (0738). If
a parameter is omitted or
specified to be 0 the default
parameter value is used. For
the cursor movement commands, the default parameter
value is 1.

Cursor Movement Commands
Cursor up
Cursor down
Cursor forward (right)
Cursor backward (left)
Direct cursor addressing

Index
Reverse index
Save cursor and attributes
Restore cursor and attributes

ESC [Pn A
ESC [ Pn B
ESC [Pn C
ESC [Pn 0
ESC [ PI; Pc H t
ESC[ PI; Pcft
ESC 0
ESCM
ESC7
ESC8

t PI = line number; Pc = column number.
Line Size (Double-height and Double-width) Commands

Change this line to double-height top half
Change this line to double-height bottom half
Change this line to single-width single-height
Change this line to double-width single-height

ESC# 3
ESC# 4
ESC# 5
ESC# 6

Character Attributes

ESC [ Ps;Ps;Ps; ... ;Ps m
Ps refers to a selective parameter. Multiple parameters are separated by the semicolon character (0738). The parameters are executed in order and have the following meanings:
o or None
All Attributes Off
1
Bold on
4
Underscore on
5
Blink on
7
Reverse video on
Any other parameter values are ignored.
Erasing

From cursor to end of line
From beginning of line to cursor
Entire line containing cursor
From cursor to end of screen
From beginning of screen to cursor
Entire screen

ESC [ K or ESC [ 0 K
ESC [ 1 K
ESC [2 K
ESC [ J or ESC [ 0 J
ESC [ 1 J
ESC [2 J

Programmable LEOs

ESC [ Ps; Ps; ... Ps q
Ps are selective parameters separated by semicolons (0738) and executed in order, as follows:
o or None
All LEOs Off
1
LED # 1 On
2
LED # 2 On
3
LED # 3 On
4
LED # 4 On
Any other parameter values are ignored.
3-14

Character Sets (GO and G 1 Designators)
The GO and G 1 character sets are designated as follows:
Character set

GO designator

G1 designator

United Kingdom (UK)
United States (USASCI!)
Special graphics characters
and line drawing set
Alternate character RO M
Alternate character ROM
special graphics characters

ESC(A
ESC (8
ESC(O

ESC)A
ESC) 8
ESC) 0

ESC ( 1
ESC (2

ESC) 1
ESC) 2

Scrolling Region
ESC [ Pt ; Pb r
Pt is the number of the top line of the scrolling region; Pb is the number of the
bottom line of the scrolling region and must be greater than Pc.
Tab Stops:
ESC H
ESC [ g or ESC [ 0 g
ESC [3 g

Set tab at current column
Clear tab at current colu mn
Clear all tabs
Modes

To Set
Sequence

Mode Name

Mode

Line feed/new line
Cursor key mode
ANSI/VT52 mode
Column mode
Scrolling mode
Screen mode
Origin mode
Wraparound
Auto repeat
Interlace
Graphic proc. option
Keypad mode

New line
Application
ANSI
132 Col
Smooth
Reverse
Relative
On
On
On
On
Application

ESC [20h
ESC[?1h
N/A
ESC [?3h
ESC [74h
ESC [?5h
ESC [?6h
ESC [77h
ESC [?8h
ESC [?9h
ESC 1
ESC =

Mode

To Reset
Sequence

Line feed
Cursor
VT52
80 Col
Jump
Normal
Absolute
Off
Off
Off
Off
Numeric

ESC [201
ESC [?11
ESC [721
ESC [?31
ESC [?41
ESC [?51
ESC [761
ESC [?71
ESC [781
ESC [791
ESC 2
ESC>

Reports
Cursor Position Report
Invoked by
Response is

ESC [6 n
ESC [ PI ; Pc R (PI = line number and Pc = column
number)

Status Report
Invoked by
Response is

ESC [5 n
ESC [ 0 n (terminal ok)
ESC [ 3 n (terminal not ok)
3-15

PROGRAMMER'S INFORMATION
What Are You
Invoked by

ESC [c
or
ESC [0 c

Response is

ESC [?1 ; Ps c

Ps is the "option present" parameter with the following meaning:

Meaning

Base VT100. no options
Processor option (STP)
Advanced video option (AVO)
AVO and STP
Graphics processor option (GO)
GO and STP
GO and AVO
GO. STP. and AVO

1
2
3
4
5
6
7

Alternately invoked by ESC Z (not recommended). Response is the same.

Reset
Reset causes the power-up reset routine to be executed.
ESC c

Confidence Tests
Fill Screen with "Es"
Invoke Test(s)

ESC # 8
ESC [2 ; Ps y

Ps is the parameter indicating the test to be done and is a decimal number computed by taking the "weight" indicated for each desired test and adding them
together.

Test
Power-up self test
(ROM checksum. RAM. NVR.
keyboard and AVO if installed)
Data Loop Back
Repeat selected test(s) indefinitely
(until failure or power off)

3-16

Weight

2 (Loop back connector required)
8

Valid ANSI
Mode Escape Sequences
(Detailed)

Definitions - The following listing defines the basic elements of the ANSI mode
escape sequences. A more complete listing appears in Appendix A.
• Control Sequence Introducer (CSI) - An escape sequence that provides
supplementary controls and is itself a prefix affecting the interpretation of
a limited number of contiguous characters. In the VT100 the CSI is ESC [.
• Parameter - (1) A string of one or more decimal characters which represent a single value; (2) The value so represented.
• Numeric Parameter - A string of characters that represent a number, designated by Pn. Pn has a range of 0 (60s) to 9 (71s).
• Selective Parameter - A string of characters that selects a subfunction
from a specified list of subfunctions, designated by Ps. In general. a control sequence with more than one selective parameter causes the same
effect as several control sequences, each with one selective parameter,
e.g., CSI Psa; Psb; Psc F is identical to CSI Psa F CSI Psb F CSI Psc F.
Ps is a string of zero or more characters with a range of 0 (60s) to 9 (71s)
with each selective parameter separated from the other by ; (73s).
• Default - A function-dependent value that is assumed when no explicit
value, or a value of 0, is specified.
• Final Character - A character whose bit combination terminates an escape
or control sequence.
Example:
delimiter
selective
parameter

~~h

C~I

Parameter
String
Final
Character
• Escape Sequences - All of the following escape and control sequences are
transmitted from the host computer to the VT100 unless otherwise noted.
All of the escape sequences are a subset of those specified in ANSI X 3.64
1977 and ANSI X 3.41 1974.
CPR

Cursor Position Report Format: ESC [ Pn; Pn R

VT100 to Host
default values: 1

The CPR sequence reports the active position by means of the parameters. This
sequence has two parameter values, the first specifying the line and the second
3-17

PROGRAMMER'S INFORMATION
specifying the column. The default condition with no parameters present, or parameters of 0, is equivalent to a cursor at home position.
The numbering of lines depends on the state of the Origin Mode (DECOM).
This control sequence is solicited by a device status report (DSR) sent from the
host.

CUB

Cursor Backward -

Host to VT100 and VT100 to Host

Editor Function; format: ESC [ Pn D

default value: 1

The CUB sequence moves the active position to the left. The distance moved is
determined by the parameter. If the parameter value is zero or one, the active
position is moved one position to the left. If the parameter value is n, the active
position is moved n positions to the left. If an attempt is made to move the cursor
to the left of the left margin, the cursor stops at the left margin.

CUD

Cursor Down -

Host to VT100 and VT100 to Host

Editor Function; format: ESC [ Pn B

default value: 1

The CUD sequence moves the active position downward without altering the column position. The number of lines moved is determined by the parameter. If the
parameter value is zero or one, the active position is moved one line downward. If
the parameter value is n, the active position is moved n lines downward. If an
attempt is made to move the cursor below the bottom margin, the cursor stops at
the bottom margin.

CUF

Cursor Forward -

Host to VT100 and VT100 to Host

Editor Function; format: ESC [ Pn C

defau It va lue: 1

The CUF sequence moves the active position to the right. The distance moved is
determined by the parameter. A parameter value of zero or one moves the active
position one position to the right. A parameter value of n moves the active position
n positions to the right. If an attempt is made to move the cursor to the right of the
right margin, the cursor stops at the right margin.

CU P

Cursor Position
Editor Function; format: ESC [ Pn; Pn H

default value: 1

The CU P sequence moves the active position to the position specified by the
parameters. This sequence has two parameter values, the first specifying the line
position and the second specifying the column position. A parameter value of zero
or one for the first or second parameter moves the active position to the first line or
column in the display, respectively. The default condition with no parameters present is equivalent to a cursor to home action. In the VT100, this control behaves
identically with its format effector counterpart, HVP.
The numbering of lines depends on the state of the Origin Mode (DECOM).
3-18

CUU

Cursor Up -

Host to VT100 and VT100 to Host

Editor Function; format: ESC [ Pn A

default value: 1

Moves the active position upward without altering the column position. The number of lines moved is determined by the parameter. A parameter value of zero or
one moves the active position one line upward. A parameter value of n moves the
active position n lines upward. If an attempt is made to move the cursor above the
top margin, the cursor stops at the top margin.

Device Attributes
format: ESC [ Pn c

DECALN

default value: 0

The host requests the VT100 to send a device attributes (DA) control
sequence to identify itself by sending the DA control sequence with
either no parameter or a parameter of O.

Response to the request described above (VT100 to host) is generated
by the VT100 as a DA control sequence with the numeric parameters
as follows:

Option Present

Sequence Sent

No options
Processor option (STP)
Advanced video option (AVO)
AVO and STP
Graphics option (GO)
GO and STP
GO and AVO
GO, STP, and AVO

ESC [71 ;Oc
ESC [71; 1c
ESC [71 ;2c
ESC [?1 ;3c
ESC [71;4c
ESC [71 ;5c
ESC [? 1 ;6c
ESC [?1 ;7c

Screen Alignment Display (DEC Private)
Format: ESC #8
This command fills the entire screen area with uppercase Es for screen focus and
alignment. This command is used by DEC manufacturing and Field Service personnel.

DECANM

ANSI/VT52 Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes only VT52 compatible escape sequences to be interpreted and executed. The set state causes only ANSI "compatible" escape and control sequences to be interpreted and executed.

DECARM

Auto Repeat Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes no keyboard keys to auto-repeat. The
set state causes certain keyboard keys to auto-repeat.
3-19

PROGRAMMER'S INFORMATION
DECAWM

Autowrap Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes any displayable characters received
when the cursor is at the right margin to replace any previous characters there. The
set state causes these characters to advance to the start of the next line, doing a
scroll up if required and permitted.

DECCOLM

Column Mode (DEC Private)
This is a private parameter apPlicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes a maximum of 80 columns on the
screen. The set state causes a maximum of 132 columns on the screen.

DECCKM

Cursor Keys Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. This mode is only effective when the terminal is in keypad
application mode (see DECKPAM) and the ANSI/VT52 mode (DECANM) is set
(see DECANM). Under these conditions, if the cursor key mode is reset the four
cursor function keys will send ANSI cursor control commands. If cursor key mode
is set the four cursor function keys will send application functions.

DECDHL

Double Height Line (DEC Private)
Format:

Top Half: ESC #3
Bottom Half: ESC #4

These sequences cause the line containing the active position to become the top
or bottom half of a double-height double-width line. The sequences must be used
in pairs on adjacent lines and the same character output must be sent to both lines
to form full double-height characters. If the line was single-width single-height all
characters to the right of the center of the screen are lost. The cursor remains over
the same character position unless it would be to the right of the right margin, in
which case it is moved to the right margin.

DECDWL

Double-Width Line (DEC Private)
Format: ESC #6
This causes the line that contains the active position to become double-width
single-height. If the line was single-width single-height all characters to the right
of the center of the screen are lost. The cursor remains over the same character
position unless it would be to the right of the right margin, in which case, it is
moved to the right margin.

DECGOFF

Graphics Processor Off (DEC Private)
Format: ESC 2
Turn off the graphics processor.
NOTE: Some DEC hardcopy terminals interpret this private escape sequence as CLEAR
TABS.

3-20

DECGO N

Graphics Processor On (DEC Private)
Format: ESC 1
All subsequent characters are interpreted as commands or data to the graphics
processor option. The terminal will remain in this mode until the graphics processor off command is received. This command is ignored if no graphics processor
option is installed.
NOTE: Some DEC hardcopy terminals interpret this private escape sequence as SET TAB.

DECHCP

Hard Copy (DEC Private)
Format: ESC #7
This causes the screen to cease updating and freeze while the hardcopy output is
enabled. The screen will resume normal operation when the hardcopy has been
completed. This command is ignored if no hard copy option is installed.

DEClO

Identify Terminal (DEC Private)
Format: ESC Z
This sequence causes the same response as the ANSI device attributes (DA). This
sequence will not be supported in future DEC terminals, therefore, DA should be
used by any new software.

DECINLM

Interlace Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state (non-interlace) causes the video processor to
display 240 scan lines per frame. The set state (interlace) causes the video processor to display 480 scan lines per frame. There is no increase in character resolution.

DECKPAM

Keypad Application Mode (DEC Private)
Format: ESC =
The auxiliary keypad keys and cursor control keys will transmit escape sequences.

DECKPNM

Keypad Numeric Mode (DEC Private)
Format: ESC >
The auxiliary keypad keys will send ASCII codes corresponding to the characters
engraved on the keys. The cursor control keys will send cursor controls.
3-21

PROGRAMMER'S INFORMATION
DECLL

Load LEOs (DEC Private)
Format: ESC I Ps q

default value: 0

Load the four programmable LEOs on the keyboard according to the parameter(s).

Parameter

o
1
2
3
4

Meaning
Clear LEOs # 1 through 4
Light LED # 1
Light LED #2
Light LED #3
Light LED #4

LED numbers are indicated on the keyboard.

DECOM

Origin Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes the origin to be at the upper-left character position on the screen. Line numbers are therefore independent of current
margin settings. The cursor may be positioned outside the margins with a cursor
position (CUP) or horizontal and vertical position (HVP) control.
The set state causes the origin to be at the upper-left character position within the
margins. Line numbers are therefore relative to the current margin settings. The
cursor is not allowed to be positioned outside the margins.
The cursor is moved to the new home position when this mode is set or reset.
Lines and columns are numbered consecutively, with the origin being line 1, column 1.

DECRC

Restore Cursor (DEC Private)
Format: ESC 8
This sequence causes the previously saved cursor position, graphic rendition, and
character set to be restored.

DECREPTPARM

Report Terminal Parameters
Format:

ESC I <sol>; <par>; <nbits>; <xspeed>;
<rspeed>; <clkmul>; <flags>x

These sequence parameters are explained below in the 0 ECREOTPARM sequence.

DECREQTPARM

Request Terminal Parameters
Format: ESC I <sol> x
The sequence OECREPTPARM is sent by the terminal controller to notify the host
of the status of selected terminal parameters. The status sequence may be sent
when requested by the host or at the terminal's discretion. DECREPTPARM is sent
upon receipt of a OECREOTPARM.

3-22

The meanings of the sequence parameters are:

Parameter

Value

Meaning

<sol>

o or none

This message is a request (DECREQTPARM) and
the terminal will be allowed to send unsolicited reports.
This message is a request; from now on the terminal
may only report in response to a request.

<par>

This message is a report (DECREPTPARM).

This message is a report and the terminal is only
reporting on request.

No pa rity set
Parity is set and odd
Parity is set and even

4
5
1

<nbits>

8 bits per character
7 bits per character

2
<xspeed>
<rspeed>

Bits per second

50
75

16
24
32
40
48
56
64
72
80
88

96
104
112
120

110

134.5
150
200
300
600
1200
1800
2000
2400
3600
4800
9600
19,200
The bit rate mUltiplier is 16.

DECSC

0-15

This value communicates the four switch values in
block 5 of SET UP B, which are only visible to the
user when an STP option is installed. These bits may
be assigned for an STP device. The four bits are a
decimal-encoded binary number.

Save Cursor (DEC Private)
Format: ESC 7
This sequence causes the cursor position, graphic rendition, and character set to
be saved. (See DEeRC.)
3-23

PROGRAMMER'S INFORMATION
DECSCLM

Scrolling Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes scrolls to "jump" instantaneously. The
set state causes scrolls to be "smooth" at a maximum rate of six lines per second.

DECSCNM

Screen Mode (DEC Private)
This is a private parameter applicable to set mode (SM) and reset mode (RM)
control sequences. The reset state causes the screen to be black with white characters. The set state causes the screen to be white with black characters.

DECSTBM

Set Top and Bottom Margins (DEC Private)
Format: ESC [ Pn; Pn r

default values: (see below)

This sequence sets the top and bottom margins to define the scrolling region. The
first parameter is the line number of the first line in the scrolling region: the second
parameter is the line number of the bottom line in the scrolling region. Default is
the entire screen (no margins). The minimum size of the scrolling region allowed is
two lines, i.e., the top margin must be less than the bottom margin.

DECSWL

Single-width Line (DEC Private)
Format: ESC #5
This causes the line which contains the active position to become single-width
single-height. The cursor remains on the same character position. This is the
default condition for all new lines on the screen.

DECTST

Invoke Confidence Test
Format: ESC [ 2 ; Ps y
Ps is the parameter indicating the test to be done. Ps is computed by taking the
weight indicated for each desired test and adding them together. If Ps is 0 no test
is performed but the VT 100 is reset.

Test
Power up self-test (ROM
checksum, RAM, NVR keyboard and AVO if installed)
Data Loop Back
Repeat Selected Test(s)
indefinitely (until failure or
power off)
3-24

Weight

2 (loop-back connector required)

DSR

Device Status Report
Format: ESC [ Ps r

default value: 0

Requests and reports the general status of the VT100 according to the following
parameter(s).

Parameter

Parameter Meaning

Response from VT100 - Ready, No malfunctions detected (default)
Response from VT100 - Malfunction retry
Command from host - Please report status (using a DSR control sequence)
Command from host - Please report active position (using a CPR control sequence)

3
5

DSR with a parameter value of 0 or 3 is always sent as a response to a requesting
DSR with a parameter value of 5.

Erase In Display
Editor Function; format: ESC [ Ps J

default value: 0

This sequence erases some or all of the characters in the display according to the
parameter. Any complete line erased by this sequence will return that line to single
width mode.

Parameter

Parameter Meaning

Erase from the active position to the end
of the screen, inclusive (default)
Erase from start of the screen to the active position, inclusive
Erase all of the display - all lines are
erased, changed to single-width, and the
cursor does not move.

Erase In Line
Editor Function; format: ESC [ Ps K

default value: 0

Erases some or all characters in the active line according to the parameter.

Parameter

Parameter Meaning

Erase from the active position to the end
of the line, inclusive (default)
Erase from the start of the screen to the
active position, inclusive
Erase all of the line, inclusive

3-25

PROGRAMMER'S INFORMATION
HTS

Horizontal Tabulation Set
Format Effector; format: ESC H
Set one horizontal stop at the active position.

HVP

Horizontal and Vertical Position
Format Effector; format: ESC [ Pn ; Pn f

default value: 1

Moves the active position to the position specified by the parameters. This sequence has two parameter values, the first specifying the line position and the
second specifying the column. A parameter value of either zero or one causes the
active position to move to the first line or column in the display, respectively. The
default condition with no parameters present moves the active position to the
home position. In the VT100, this control behaves identically with its editor function counterpart, CUP. The numbering of lines and columns depends on the reset
or set state of the origin mode (DECOM).

IND

Index
Format Effector; format: ESC D
This sequence causes the active position to move downward one line without
changing the column position. If the active position is at the bottom margin, a
scroll up is performed.

LNM

Line Feed/New Line Mode
This is a parameter applicable to set mode (SM) and reset mode (RM) control sequences. The reset state causes the interpretation of the line feed (LF). defined in
ANSI Standard X3.4-1977, to imply only vertical movement of the active position
and causes the return key (CR) to send the single code CR. The set state causes
the LF to imply movement to the first position of the following line and causes the
return key to send the two codes (CR. LF). This is the New Line (N L) option.
This mode does not affect the index (lND). or next line (NEL) format effectors.

NEL

Next Line
Format Effector; format: ESC E
This sequence causes the active position to move to the first position on the next
line downward. If the active position is at the bottom margin, a scroll up is performed.

Reverse Index
Format Effector; format: ESC M
Move the active position to the same horizontal position on the preceding line. If
the active position is at the top margin, a scroll down is performed.

3-26

RIS

Reset To Initial State
Format: ESC c

Reset the VT100 to its initial state, i.e., the state it has after it is powered on. This
also causes the execution of the power-up self-test and signal I N IT H to be asserted briefly.

Reset Mode
default value: none

Format: ESC ( Ps ;Ps ; ... ; Ps I

Resets one or more VT100 modes as specified by each selective parameter in the
parameter string. Each mode to be reset is specified by a separate parameter. [See
Set Mode (SM) control sequence.] (See Modes following this section.)

SCS

Select Character Set
The appropriate GO and G 1 character sets are selected from the five possible
character sets. The GO and G 1 sets are selected by the codes SI and SO (shift in
and shift out) respectively.

GO Sets

G1 Sets

Sequence

Meaning

ESC (A
ESC (B
ESC (0
ESC ( 1

ESC)A
ESC) B
ESC) 0
ESC) 1

ESC (2

ESC) 2

United Kingdom Set
ASCII Set
Special Graphics
Alternate Character ROM
Standard Character Set
Alternate Character ROM
Special Graphics

The United Kingdom and ASCII sets conform to the "ISO international register of
character sets to be used with escape sequences." The other sets are private
character sets. Special graphics means that the graphic characters for the codes
1378 to 176 8 are replaced with other characters. The specified character set will
be used until another SCS is received.

SG R

Select Graphic Rendition
Format Effector; format: ESC ( Ps; ... ; Ps m

default value: 0

Invoke the graphic rendition specified by the parameter(s). All following characters
transmitted to the VT100 are rendered according to the parameter(s) until the next
occurrence of SG R.

Parameter

Parameter Meaning

Attributes off
Bold or increased intensity
Underscore
Blink
Negative (reverse) image

1
4
5
7

3-27

PROGRAMMER'S INFORMATION
All other parameter values are ignored.
Without the Advanced Video Option only one character attribute is possible as
determined by the cursor selection; in that case specifying either the underscore or
the reverse attribute will activate the currently selected attribute. (See cursor selection in Chapter 1.)

Set Mode
format: ESC [ Ps; ... ; Ps h

default value: none

Causes one or more modes to be set within the VT100 as specified by each
selective parameter in the parameter string. Each mode to be set is specified by a
separate parameter. A mode is considered set until it is reset by a reset mode (RM)
control sequence.

TBC

Tabulation Clear
Format Effector; format: ESC [ Ps g

default value: 0

Parameter

Parameter Meaning

Clear the horizontal tab stop at the active
position (the default case).
Clear all horizontal tab stops.

3
Any other parameter values are ignored.

MODES

The following is a list of VT100 modes which may be changed with set mode (SM)
and reset mode (RM) controls.

ANSI Specified Modes

Parameter

Mode
Mnemonic
LNM

Mode Function
Error (ignored)
Line feed new line mode

DEC Private Modes
If the first character in the parameter string is ? (77 8 ), the parameters are interpreted as DEC private parameters according to the following:

Parameter
0
1
2

3
4
5
6
7
8

9
3-28

Mode
Mnemonic

Mode Function

DECCKM
DECANM
DECCOLM
DECSCLM
OECSCNM
OECOM
OECAWM
OECARM
OECINLM

Error (ignored)
Cursor key
ANSI/VT52
Column
Scrolling
Screen
Origin
Auto wrap
Auto repeating
Interlace

Any other parameter values are ignored.
The following modes, which are specified in the ANSI X3.64-1977 standard, may
be considered to be permanently set. permanently reset, or not applicable, as
noted. Refer to that standard for further information concerning these modes.

Valid VT52
Mode Escape Sequences
(detailed)

Mode
Mnemonic

Mode Function

State

CRM
EBM
ERM
FEAM
FETM
GATM
HEM
IRM
KAM
MATM
PUM
SATM
SRTM
TSM
TTM
VEM

Control representation
Editing boundary
Erasure
Format effector action
Format effector transfer
Guarded area transfer
Horizontal editing
Insertion-replacement
Keyboard action
Multiple area transfer
Positioning unit
Selected area transfer
Status reporting transfer
Tabulation stop
Transfer termination
Vertical editing

Reset
Reset
Set
Reset
Reset
NA
NA
Reset
Reset
NA
Reset
NA
Reset
Reset
NA
NA

Graphics Processor On
Format: ESC 1
All subsequent characters are interpreted as commands to the graphics option
until the graphics processor off command is received. This sequence is ignored if
no graphics processor is installed.

Graphics Processor Off
Format: ESC 2
Turn off the graphics processor.

Cursor Up
Format: ESC A
Move the active position upward one position without altering the horizontal position. If an attempt is made to move the cursor above the top margin, the cursor
stops at the top margin.

Cursor Down
Format: ESC B
Move the active position downward one position without altering the horizontal
position. If an attempt is made to move the cursor below the bottom margin, the
cursor stops at the bottom margin.
3-29

PROGRAMMER'S INFORMATION
Cursor Right
Format: ESC C
Move the active position to the right. If an attempt is made to move the cursor to
the right of the right margin, the cursor stops at the right margin.

Cursor Left
Format: ESC 0
Move the active position one position to the left. If an attempt is made to move the
cursor to the left of the left margin, the cursor stops at the left margin.

Enter Graphics Mode
NOTE
The special graphics
characters in the VT100
are different from those
in the VT52.

Format: ESC F
Causes the special graphics character set to be used.

Exit Graphics Mode
Format: ESC G
This sequence causes the standard ASCII character set to be used.

Cursor to Home
Format: ESC H
Move the cursor to the home position.

Reverse Line Feed
Format: ESC I
Move the active position upward one position without altering the column position. If the active position is at the top margin, a scroll down is performed.

Erase to End of Screen
Format: ESC J
Erase all characters from the active position to the end of the screen. The active
position is not changed.

Erase to End of LineFormat: ESC K
Erase all characters from the active position to the end of the current line. The
active position is not changed.

3-30

Direct Cursor Address
Format: ESC V line column
Move the cursor to the specified line and column. The line and column numbers
are sent as ASCII codes whose values are the number plus 037 8; e.g .. 0408 refers
to the first line or column. 0508 refers to the eighth line or column. etc.

Identify
NOTE
Information regarding
options must be obtained in ANSI mode,
using the device attributes (DA) control sequence.

Format: ESC Z
This sequence causes the terminal to send its identifier escape sequence to the
host. This sequence is:
ESC / z.

Enter Alternate Keypad Mode
Format: ESC =
The optional auxiliary keypad keys will send unique identifiable escape sequences
for use by applications programs.

Exit Alternate Keypad Mode
Format: ESC >
The optional auxiliary keypad keys send the ASCII codes for the functions or characters engraved on the key.

Enter ANSI Mode
Format: ESC <
All subsequent escape sequences will be interpreted according to ANSI Standards
X3.64-1977 and X3.41-1974. The VT52 escape sequence designed in this section will not be recognized.

3-31

CHAPTER 4
VT100 Options

CHAPTER 4
VT100 OPTIONS

The VT100 has available options which are designed to enhance the basic terminal
and allow its use in a wide range of applications. The options currently available
are:
VT1XX-AA
VT1XX-AB

20 rnA Current Loop Option
Adva nced Video Option

In the future, additional options will be available which will further enhance the
basic VT100. Contact the nearest DIGITAL Sales Office for further information and
how to order the options.

ADVANCED VIDEO OPTION - VT1XX-AA
The Advanced Video Option enhances the basic VT100 by adding the following
features:
• 10 additional lines of 132 column display - this capability is added to the
VT100 by providing additional display memory. The screen can now displaya total of 24 lines in either 80- or 132-column format.
• Additional character attributes - the VT100 is now capable of highlighting
any character(s) on the screen in any of the following ways:
Bold
Blink
Underline
Reverse
Any combination of the above
4-3

VT100 OPTIONS
• Capability of an additional character generator ROM - this capability is
added to the VT100 by providing the memory required to access a second
character generator ROM.
Advanced Video Option Installation
Use the following procedure to install the Advanced Video Option.

Remove power from the "terminal by disconnecting the ac plug.

Unplug the keyboard (Figure 4-1).

Unplug any connectors from the composite video input/output jacks.

Disconnect the communications cable.

With a blade-type screwdriver loosen the four captive screws holding
the access cover.

If the 20 mA Current Loop Option is installed, gently pull the access
cover away from the terminal about 2 inches; then reach in and disconnect J5 from the terminal controller board.

Remove the access cover.

Remove any graphic or STP cables.

CAPTIVE
SCREWS (4)

ACCESS
COVER

l
d
·~__~mmm_ _-

EIA
COMMUNICATIONS
CONNECTOR
EXTERNAL
VIDEO
COMMUNICATIONS

MAIN FUSE
POWER SWITCH

KEYBOARD
CONNECTOR

POWER
SELECTOR
SWITCH

CONNECTOR

OPTIONAL 20mA
Figure 4-1
VT1 00 Rear View

4-4

COMMUNICATION
CONNECTOR

MA-1987

Remove the terminal controller board by gently but firmly pulling the
board straight out. The terminal controller board is located in the leftmost slot in the card cage (viewed from the rear).

10.

Place the terminal controller board on a flat surface with the component side up (Figure 4-2).

11.

Locate the four mounting holes drilled in the terminal controller board;
mount a standoff in each.

12.

Grasp the advanced video board by the edges and carefully align the
connector pins with the connector on the terminal controller board.
Gently but firmly mount the advanced video board onto the terminal
controller board.

13.

Reinstall the terminal controller board. The terminal controller board
must be inserted into the leftmost slot in the card cage.

14.

Reinstall all cables removed.

15.

Reinstall the access cover.

CONTROLLER
ADVANCE
VIDEO
BOARD J1 ADVANCE
VIDEO

TERMINAL
CONTROLLER
BOARD

CONN ECTIDlR

~J2 GRAPHICS
CONNECTOR

n:
LF

J520mA
CURRENT LOOP
CONNECTOR

o
J4 EIA
COMMUNICATIONS
CONNECTOR

J8 VIDEO IN
CONNECTOR

Figure 4-2
Advanced Video Option
Installation

J9 VIDEO OUT
CONNECTOR
J7 KEYBOARD
CONNECTOR
MA-1995

4-5

VT100 OPTIONS
Advanced Video Option Checkout
Use the following procedure to check out the operation of the Advanced Video
Option.
1.

Turn the terminal power on and verify that no error was detected during
the power up self-test.

Press the SET-UP key. The words "SET-UP A" should blink in boldface,
the words "TO EXIT PRESS SET-UP" should be underlined, and the
ruler should contain alternating normal and reverse video fields.

Place the terminal in the 132 column mode and then in the LOCAL
mode.

Exit SET-UP and type the following sequence:
ESC
ESC #8

The screen should now display 24 lines X 132 columns.

20 mA CU RRENT LOOP OPTION - VT1XX-AA
The 20 rnA Current Loop Option allows the VT100 to connect directly to the host
computer over a short distance without using a modem. The specifications for the
20 rnA Current Loop Option are located in Chapter 2 of this manual under interface information.

20 mA Current Loop Option Installation
Use the following procedure to install the 20 rnA Current Loop Option:

4-6

Remove power from the terminal by disconnecting the ac plug.

Unplug the keyboard.

Unplug any connectors from the composite video input/output jacks.

Disconnect the communications cable.

With a blade-type screwdriver loosen the four captive screws holding
the access cover; then remove the cover.

Set the TRANS switch to the NORMAL position (Figure 4-3). (If the
terminal must provide current on the receiver line set the switch to the
ACT position.)

Set the REC switch to the NORMAL position (Figure 4-3). (If the terminal must provide current on the receive line set the switch to the ACT
position.)

Connect P5 to J5 on the terminal controller board (Figure 4-4).

Perform the 20 rnA Current Loop Option Checkout.

a
CAPTIVE
SCREWS (4)

.--_ _ _ _ ACCESS
COVER

20mA
CURRENT
TOP BOARD

TRANSMIT
LINE
SWITCH
RECEIVE
LINE
SWITCH

20mA
COMMUNICATIONS
CONNECTOR

Figure 4-3
20 rnA Current Loop Option

MA-1996

20 rnA Current Loop Option Checkout
The VT100 contains an internal test called the data loopback test. In the data
loopback test the VT100 transmit and receive lines are connected to each other
via a special external connector. A predefined set of characters are then transmitted. The terminal receives the characters and compares them to the characters
transmitted. If the characters do not match an error is then flagged.

Use the following procedure to check out the operation of the 20 mA Current Loop
Option.

Disconnect the terminal from the communications line.

With the Transmit Line Switch and Receive Line Switch in the normal
position, connect the 20 mA loopback connector (PN 70-15503-00) to the
Mate-N-Lok connector mounted to the bottom of the access cover.

Place the terminal in ANSI-compatible mode (in SET-UP B group 2 switch 3
equals a 1).

4-7

VT100 OPTIONS

COVER
WITH 20m A
OPTION

TERMINAL
CONTROLLER
BOARD

Figure 4-4
Terminal Controller Board

4-8

MA-1997

Type the following sequence to perform the data loopback test: ESC [2';2Y

Once the test is complete return the 20 mA current loop board switches to
the original positions, remove the loopback connector, and reconnect the
terminal to the communications line.

Appendixes

APPENDIX A
ANSI DEFINITIONS AND NOTATION

Active position - The character position on the visual
display that is to display the graphic symbol representing the next graphic character.

Control sequence introducer (CSI) - An escape sequence that provides supplementary controls and that
is itself a prefix affecting the interpretation of a limited
number of contiguous characters.

ANSI mode - A VT100 mode in which it recognizes
and responds only to escape sequences whose syntax
and semantics are in accordance with ANSI specifications.

Control string - A string of characters that is used to
perform a control function and that is delimited by an
opening and closing delimiter control.

Character position -That portion of a visual display
which is displaying or is capable of displaying a graphic
symbol.

Cursor - A visual representation of the active position
which is either a blinking reverse-video or blinking underline.

Control - A control character, an escape sequence, or
a control sequence that performs a control function.

Cursor control - An editor function that moves the
active position.

Control character - A character whose occurrence in
a particular context initiates, modifies, or stops a control function.
Control function - An action that affects the recording, processing, transmission, or interpretation of data.
Control sequence - A sequence of characters that is
used for control purposes to perform a control function,
that begins with the control sequence introducer (CSI)
control. and that may contain a parameter string.

Default - A function-dependent value that is assumed
when no explicit value, or a value of 0, is specified.
Display - The current active area of the screen, i.e., the
area inside the scrplling region, or the entire screen,
depending on the origin mode.
Editor function - A control that affects the layout or
positioning of previously entered or received information in a printing or cathode ray tube device and that is
intended to be interpreted and executed without remaining in the data stream. (See format effector.)
A-3

APPENDIX A
Escape character (ESC) - A control character that
provides supplementary characters (code extension)
and that is itself a prefix affecting the interpretation of
a limited number of contiguous characters.
Escape sequence - A sequence of characters that is
used for control purposes to perform a control function
and whose first character is the escape (ESC) control
character.
Final character - A character whose bit combination
terminates an escape or control sequence designated
by F.
Format effector - A control that affects the layout or
positioning of information on the screen and that may
remain in the data stream subsequent to interpretation
and processing. (See editor function.)
Graphic character - A character. other than a control
character. that has a visual representation normally
handwritten. printed. or displayed.
Home - The character position at the origin. [See origin mode (DECOM).]

Intermediate character - A character whose bit combination precedes a final character in an escape or control sequence.
Numeric parameter - A string of bit combinations
that represents a number. designated by Pn.
Parameter - (1) A string of one or more characters
that represent a single value: (2) The value so represented.
Parameter string - A string of characters that represent one or more parameter values.
Selective parameter - A string of bit combinations
that selects a subfunction from a specified list of subfunctions. designated by Ps. In general. a control sequence with more than one selective parameter causes
the same effect as several control sequences. each
with one selective parameter. e.g .. CSI Psa; Psb; Psc F
is identical to CSI Psa F CSI Psb F CSI Psc F.
VT52 mode - A VT100 mode in which it recognizes
and responds only to escape sequences which DEC
VT52 type terminals use.

Notation
1.
I - An intermediate character in an escape sequence or a control sequence. where I is from 408 to
578 inclusive.
2.

A-4

F - A Final character in:
a.

An escape sequence. where F is from 608 to 1768 inclusive.

A control sequence, where F is from 1008 to 1768 inclusive.

Pn - A numeric parameter in a control sequence. where Pn is a string of zero or more characters
from 608 to 718 inclusive.

Ps - A variable number of selective parameters in a control sequence. with each selective parameter separated from the other by 738. Ps is a string of zero or more characters from 608 to 718
inclusive and 738.

Example: The format of an escape sequence as defined in American National Standard X 3.41-1974 and used in the VT100 is:
ESC I ... I F
Where:
a.

ESC is the introducer control character (338) that is named escape.

I ... I are the intermediate bit combinations that mayor may not be present. I characters are
bit combination 408 to 578 inclusive in both 7 -and 8-bit environments.

F is the final character. F characters are bit combinations 60s to 1768 inclusive in escape
sequences in both 7 - and 8-bit environments.

The occurrence of characters in the inclusive ranges of 08 to 378 is technically an error
condition whose recovery is to execute immediately the function specified by the character
and then continue with the escape sequence execution. The exceptions are: If the character
ESC occurs, the current escape sequence is aborted, and a new one commences, beginning
with the ESC just received. If the character CAN (308) or the character SUB (328) occurs, the
current escape sequence is aborted.

A-5

APPENDIX B
ASCII CODE CHART

~
~b'

0
0
0

h6
S

.I-

~
Row.l-

1
1
1

1
1

NUL
SOH
STX
ETX
EaT
ENQ
ACK
BEL
BS
HT
LF

FF
CR
SO
SI

4
5

1
1
1
1

14
15

1
1

0
2

1
1

1
3

1
1

DLE

DCI

1
2

A
B

("'

DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US

W
X

!:.t

(

"7
8

~.~

)

\:l

..i

[

{

;

L --

....

]

ITI

}

:::.

[)

*
+

I
I

DEL

STANDARD (ASCII) CHARACTER SET

8-1

EK-VT100-UG-Cl

TECHNICAL DOCUMENTATION
CHANGE NOTICE

VT100 USER GUIDE
EK- VT 1OO-U G-OO 1
ERRA TA SHEET

The changes on the following pages have been made to avoid confusion between the
uppercase I (111 8 ) and the lowercase L (154 8) characters. The changes are indicated by
a change bar in the margin. Please note this distinction in your copy.
Page No.

Date

3-9
3-15
3-27

November 1978
November 1978
November 1978

, Printed in U.S.A.

digital equipment corporation • maynard, massachusetts

Auxiliary Keypad - The keys on the auxiliary keypad normally transmit the codes
for the numerals, decimal point, ~inus sign, and comma. In addition, the key
labeled ENTER transmits the same code as the RETURN key. The host cannot tell
if these keys were typed on the auxiliary keypad as opposed to the corresponding
keys on the main keyboard. Therefore, software which requires considerable numeric data entry need not be rewritten to use the keypad.
However, if software must be able to distinguish between pressing a key on the
auxiliary keypad and pressing the corresponding key on the main keyboard for
instance, the host can give the terminal a command to place it in keypad application mode. In keypad application mode all keys on the auxiliary keypad are
defined to give escape sequences which may be used by the host as user-defined
functions.

Table 3-7
VT52 Mode
Auxiliary Keypad Codes

The codes sent by the auxiliary keypad for the four combinations of the
VT52/ AN SI mode and keypad numeric/application mode are shown in Tables 3-7
and 3-8. None of the keys are affected by pressing the SH I FT, CAPS LOCK, or
CONTROL keys.
Key

Keypad
Numeric Mode

Keypad
Application Mode

7
8

· (comma)
· (period)

ESC? p
ESC? q
ESC? r
ESC? s
ESC? t
ESC? u
ESC? v
ESC? w
ESC? x
ESC? y
ESC? m
ESC? 1*
ESC? n

ENTER
PF1
PF2
PF3
PF4

Same as RETU RN key
ESC P
ESCQ
ESCR
ESCS

ESC? M
ESC P
ESCQ
ESC R
ESCS

Key

Keypad
Numeric Mode

Keypad
Application Mode

1
2
3
4
5
6

•
Table 3-8
ANSI Mode
Auxiliary Keypad Codes

1
2

3
4
5
6
7

8
9

•
•

NOTE
In ANSI mode, if the codes
are echoed back to the
VT100, or if the terminal is in
local mode, the last character
of the sequence will be displayed on the screen; e.g.,
PF1 will display a "P."

· (comma)
· (period)
ENTER
PF1
PF2
PF3
PF4

2
3
4

5
6
7

ESC a p
ESC Oq
2
ESC r
ESC s
3
ESC t
4
ESC au
5
ESCOv
6
ESCOw
7
ESC Ox
8
9
ESCQy
ESCO m
. (comma)
ESC 1*
ESCO n
· (period)
Same as RETURN key ESCOM
ESCO P
ESC
P
ESCOQ
ESCOQ
ESCOR
ESCO R
ESCO S
ESCO S

a
a
a

* The last character of the sequence is a lowercase L (1548 ),

3-9
November 1978

Character Se.ts (GO'and G1 Designators)
The GO and G 1 character sets are designated as follows:
Character set

GO designator

G1 designator

United Kingdom (UK)
United States (USASCII)
Special graphics characters
and line drawing set
Alternate character ROM
Alternate character ROM
special graphics characters

ESC (A
ESC (B
ESC (0

ESC)A
ESC) B
ESC) 0

ESC ( 1
ESC (2

ESC) 1
ESC )2

ESC H
ESC [ g or ESC [ 0 g
ESC [3 g

Modes
To Set
Sequence

Mode Name

Mode

Line feed/new line
Cursor key mode
ANSI/VT52 mode
Column mode
Scrolling mode
Screen mode
Origin mode
Wraparound
Auto repeat
Interlace
Graph ic proc. option
Keypad mode

New line
Application
ANSI
132 Col
Smooth
Reverse
Relative
On
On
On
On
Application

ESC [20h
ESC[71h
N/A
ESC [73h
ESC [74h
ESC [75h
ESC [76h
ESC [77h
ESC [7Sh
ESC [79h
ESC 1
ESC =

Mode

To Reset
Sequence

Line feed
Cursor
VT52
SO Col
Jump
Normal
Absolute
Off
Off
Off
Off
Numeric

ESC [201*
ESC [71/*
ESC [721*
ESC [73/*
ESC [74/*
ESC [75/*
ESC [76/* .
ESC [77/*
ESC [7S/*
ESC [79/*
ESC2
ESC>

Reports
Cursor Position Report
Invoked by
Response is

ESC [6 n
ESC [PI
number)

Pc R (PI = line number and Pc = column

Status Report
Invoked by
Response is

ESC [5 n
ESC [ 0 n (terminal ok)
ESC [ 3 n (terminal not ok)

* The last character of the sequence is a lowercase L (1548 ),

3-15

November 1978

•

RIS

Reset To Initial State
Format: ESC. c

Reset the VT100 to its initial state, i.e., the state it has after it is powered on. This
also causes the execution of the power-up self-test and signal INIT H to be asserted briefly.

•

Reset Mode
Format: ESC [ Ps ;Ps ; ... ; Ps 1*

default value: none

SCS

GO Sets

G1 Sets

Sequence

Meaning

ESC(A
ESC (B
ESC (0
ESC ( 1

ESC) A
ESC) B
ESC) 0
ESC) 1

ESC(2

ESC) 2

United Kingdom Set
ASCII Set
Special Graphics
Alternate Character ROM
Standard Character Set
Alternate Character ROM
Special Graphics

The United Kingdom and ASCII sets conform to the "ISO international register of
character sets to be used with escape sequences." The other sets a re private
character sets. Special graphics means that the graphic characters for the codes
1378 to 176 8 are replaced with other characters. The specified character set will
be used until another SCS is received.

SGR

Select Graphic Rendition
Format Effector; format: ESC [ Ps; ... ; Ps m

default value: 0

Invoke the graphic rendition specified by the parameter(s). All following characters
transmitted to the VT100 are rendered according to the parameter(s) until the next
occurrence of SGR.

Parameter

Parameter Meaning

Attributes off
Bold or increased intensity
Underscore
Blink
Negative (reverse) image

1
4

5
7

•

* The last character of the sequence is a lowercase L (1548 ),

3-27
NnVAmhAr 197R

•