First Edition, November 1989
The information in this document is subject to change without notice and should not
be construed as a commitment by Digital Equipment Corporation. Digital Equipment
Corporation assumes no responsibility for any errors that may appear in this document.
The software described in this document is furnished under a license and may be used or
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and Computer Software clause at DFARS252.227-7013.
Copyright © by Digital Equipment Corporation 1989
All Rights Reserved.
Printed in Taiwan.
FCC NOTICE: The equipment described in this manual generates, uses, and may emit
radio frequency energy. The equipment has been type tested and found to comply withthe limits for a Class A computing device pursuant to Subpart J of Part 15 of FCC
Rules, which are designed to provide reasonable protection against such radio frequency
interference when operated in a commercial environment. Operation of this equipment ina residential area may cause interference, in which case the user at his own expense may
be required to take measures to correct the interference.
AT&T is a trademark of American Telephone and Telegraph Company:
The following are trademarks of Digital Equipment Corporation:DEC
DEC-423
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DmOL
LA12, ~4,LA35
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LA75 Companion PrinterLA100, LA210
LJ250, LJ251
LN01, LN03
LQP02, LQP03'MASSBUS
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RSX
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VMS
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VT220, VT320, VT420~DmDDmD1M

This document was prepared and published by Educational Services Development andPublishing, Digital Equipment Corporation.

Contents
About This Guide

1

Xl

A Look at the Terminal

VT420 Components ............... . . . . . . . . . . . . . . . . . . . . .
TerIIlinal ..........................................
Keyboard. . ... . .. . .... . . . .. . . . . . . . . . . .. . . . .. . . . . . . .
Your Computer System .................................
Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set-Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Two Sessions ................................... . . . .
Windows................................ .......... .
Number of Lines on the Screen . . . . . . . . . . . . . . . . . . . . . . . . .
Page Memory ...................................'. . . .
Copy and Paste ....................... . . . . . . . . . . .. . .
Status Line ........................................
Keyboard Indicator Line ..............................
Screen Alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Screen Background ..................................
Emulating VT Series Text Terminals . . . . . . . . . . . . . . . . . . . . .
Character Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programming the Tenninal ................... . . . . . . . . . . .

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iii

iv

Contents

Installing
2Your VT420 Video Terminal

Installation

Site Considerations
Installation
Cable Connections .
Problem Solving
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Getting Started

Setting Up the VT420 for One or Two Sessions
Setting Up for One Session (One Cable) o.
Setting Up for Two Sessions (Two Cables)
Setting Up for Two Sessions with SSU Software (One Cable)
Selecting the Correct Baud Rate
Selecting the Correct Terminal ID
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Using· Your VT420 Video Terminal

4

The Keyboard and Indicators

LK401 Keyboard
Main Keypad
Editing Keypad
Nmneric Keypad
Top-Row Function Keys
Compose Characters
Indicator Lights
Audible Indicators
KeyclickBell
Keyboard Indicator Line .
Status Line
Word Processing Keyboard.

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Contents

5

Using S~t-Up

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Independent Setups for Two Sessions ....................
Entering and Leaving Set-Up ............................
Set-Up Directory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Line and Keyboard Indicator Line .................
Set-Up Cursor .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Action Fields .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set-Up Directory Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting Set-Up Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Changing and Recalling Settings . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Change Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Save Your Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Recall Saved Settings ..........................
Global Set-Up Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Two Sessions .................................. . . . . .
Display Set-Up Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting a Page Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting the Number of Lines/Screen . . . . . . . . .. . . . . . . . . . .
Coupling the Cursor to the Display . . . . . . . . . . . . . . . . . . . . . .
General Set-Up Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Character Sets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communications Set-Up Screen. . . . . . . . . . . . . . . . . . . . . . . . . . .
Keyboard Set-Up Screen ................................
Ta.b Set-Up Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

v

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Typing Additional Characters

What Characters Can I Type? .................. . . . . . . . . . .
How to Type a Character Using the Compose Character Key . . . .
Invalid Sequences ......................................
Canceling or Restarting a Compose Sequence . . . . . . . . . . . . . .
Hexadecimal Compose Sequences .........................

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vi

Contents

7

Using Two Sessions, Windows, and the Copy and Paste
FeatureWhat Are Sessions? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
'I'w-o Sessions .........................................
Opening Two Sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If You Use Two Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If You Use One Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Restoring an Interrupted SSU Session. . . . . . . . . . . . . . . . . . . .
SSU Screen and Error Messages . . . . . . . . . . . . . . . . . . . . . . . .
Which Session is Active? ................................
Number of LinesiScreen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Change the Number of LinesiScreen . . . . . . . . . . . . . . .
Windows.............................................
One Window. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Two Windows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Select One or Two Windows . . . . . . . . . . . . . . . . . . . . . .
Keeping the Cursor Visible ............................
How to Change Window Sizes ...... . . . . . . . . . . . . . . . . . . . .
Panning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Pan ........................................
Copying and Pasting Text ...............................
Copying Text into the Paste Buffer ......................
Pasting Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Notes About Copying and Pasting Text. . . . . . . . . . . . . . . . . . .

8

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Printers and Modems

Printers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting a Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selecting a Print Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal Mode: Printing Pages of Text . . . . . . . . . . . . . . . . . . . .
Auto Print Mode: Printing Text from the Host System. . . . . . .
Printer Controller Mode: Letting the Host Control Printing . . .
Local Controller Mode: Setting Up the Printer. . . . . . . . . . . . .
Assigning a Printer in 'I'w-o Sessions .......................
Printer Set-Up Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Contents

Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . ... . . . . . .
Connecting to a Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

111
111

VT420 Programming Summary

2 Character Encoding ..................................
3 Keyboard Codes .....................................
4 Emulating VT Series Terminals. . . . . . . . . . . . . . . . . . . . . . . . .
5 Using Character Sets .................................
6 Page Memory .......................................
7 Visual Character and Line Attributes . . . . . . . . . . . . . . . . . . . . .
8 Editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 Rectangular Area Operations. . . . . . . . . . . . . . . . . . . . . . . . . . .
10 Cursor Movement- and Panning. . . . . . . . . . . . . . . . . . . . . . . . .
11 Keyboard, Printing, and Display Commands. . . . . . . . . . . . . . .
12 VT420 Reports .....................................
13 Resetting and Testing the Terminal .....................
14 Session Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A VT52 Mode Control Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

vii

113
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122
122
128
129
130
131
132
133
136
142
143
143

Solving Problems and Getting Service

Operating Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-Up Self-Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Error Messages .......................................
Digital Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On-Site Hardware Services ............................
Off-Site Hardware Services ............................
Software Service ......................................
How to Get Service ....................................

144
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148
148
148

viii

Contents

A

Specifications

Site Planning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • .
Operating Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LK401 Keyboard ......................................

B

Supplies and Docu mentation

Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cables ..............................................
Related Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ordering Information .. ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C

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152

153
154
154
155

Communication

Cables ..............................................
XONIXOFF Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Modem Connections and Disconnections ....................
Break Function .......................................
Connector Signals .....................................
Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

156
158
159
160
160
161

Glossary
Figures
1-1
3-1
6-1
C-1
C-2

VT420 Video Terminal. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set-Up Directory ........................... . . . . . .
Hexadecimal Compose Keys. . . . . . . . . . . . . . . . . . . . . . . . .
Cables.........................................
6-Pin Connector Pinouts ...........................

2
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160

Contents

ix

Tables
4-1
4-2
5-1
5-2
5-3

Keyboard Indicator Line Fields. . . . . . . . . . . . . . . . . . . . . .
Status Line Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Set-Up Directory Features. . . . . . . . . . . . . . . . . . . . . . . . . .
Global Set-Up Features . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Display Set-Up Features .... . . . . . . . . . . . . . . . . . . . . . . .
5-4 General Set-Up Features. . . . . . . . . . . . . . . . . . . . . . . . . . .
5-5 Communications Set-Up Features . . . . . . . . . . . . . . . . . . . .
5-6 Keyboard Set-Up Features. . . . .. . . . . . . . . . . . . . . . . . . . .
5-7 Tab Set-Up Features ..............................
6-1 Key Sequences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8-1 Printer Set-Up Features ...........................
9-1 Alias Primary DA Responses From the VT420. . . . . . . . . . .
9-2 ANSI Modes for DECRQM, DECRPM, SM, and RM . . . . . .
9-3 DEC Private Modes for DECRQM, DECRPM, SM, and RM.
9-4 Control Functions forDECRQSS Requests .............
10-1 Common Operating Problems .......................
10-2 Screen Error Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C-1 6-Pin DEC-423 Connector Interface Signals (Comm 1 or
Com.m 2) .......................................

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This guide provides the information you need to install, operate, andmaintain your VT420 video terminal. The guide describes the North
American version of the VT420 video terminal. A worldwide version is
also available.
The guide also provides a summary of the control functions that
programmers can use when writing applications for the VT420 terminal.
For more detailed programming information, you can order the VT420
Programtner Reference Manual from Digital. See Appendix B for ordering
information and a complete list of related documentation.

Organization
This guide has 10 chapters, 4 appendices, and a glossary. If you arealready familiar with video terminals, you may want to go immediately tothe installation section, Chapters 2 and 3.
NOTE

A handy summary of keyboard functions appears at the back of
the manual.
•

Chapter 1, "A Look at the Terminal," gives you an overview of theVT420 terminal and its features.

Installing Your VT420 Video Terminal•

Chapter 2, "Installation," shows you how to install your terminal andconnect it to a host computer system, terminal server, or modem.
Depending on· your installation, you can use the terminal with twocomputer systems at the same time.
xi

xii

About This Guide•

Chapter 3, "Getting Started," describes how to set your terminal's
operating features to match your installation.

Using Your VT420 Video Terminal•

Chapter 4, "The Keyboard and Indicators," describes the terminal's
keyboard and explains the general function of each key. The chapter
also describes the terminal's indicators and status lines.

•

Chapter 5, "Using Set-Up," describes how to use the VT420 set-up
screens. You use set-up screens to examine and change the settings ofoperating features from the keyboard.

•

Chapter 6, "Typing Additional Characters," describes how to selectcharacters that do not appear as standard characters on yourkeyboard (such as accented letters).

•

Chapter 7, "Using Two Sessions, Windows, and the Copy and Paste
Feature," describes how to use two sessions and windows on yourVT420. Depending on your installation, you can log into two computer
systems and view information from both systems at the same time.

•

Chapter 8, "Printers and Modems," describes how to use a printer ormodem with your terminal.

•

Chapter 9, "VT420 Programming Summary," is a summary of control
functions that programmers can use with the VT420 terminal. The
chapter shows the· character sets that are built into the terminal.

•

Chapter 10, "Solving Problems and Getting Service," provides
suggested solutions for typical operating problems and tells youwhere to get more help.

Appendices•

Appendix A lists VT420 specifications.

•

Appendix B provides ordering information for supplies anddocumentation.

•

Appendix C provides detailed information on communication with ahost computer system, including cables and connector signals.

About This Guide

xiii

Conventions
The following conventions are used in this manual:Cautions

Provide information to prevent damage to equipment.

Notes

Provide general operating infonnation.

Set-up features

The names of features appear in bold type.
Example: Use the save feature in the Set-Up
Directory screen.
Set-up feature settings and fields appear in this type.
Example: The cursor is on the Global field in the
Set-Up Directory.

Keyboard keys

Appear in a Ibox I.

I

I

Example: Press the Return key.
For ICtr11 key sequences, hold down ICtr11 and press theother key.
Glossary entries

Appear in italics when first used in text.
Example: The VT420 stores information in its page
memory.

This chapter introduces you to the VT420 video display terminal. The
VT420 is a general-purpose terminal that you use to communicate with ahost computer system. The chapter provides an overview of the terminal
and its basic operating features. The chapter also tells you where to lookin this guide for more iuformation about each feature.

VT420 Components
The VT420 has two main components, a monitor/terminal unit and a
keyboard (Figure 1-1). The monitor/terminal unit is simply called theterminal in the rest of this guide.

Terminal
The VT420 uses a 359 mm (14 inch) monochrome screen. The VT420
screen can display 24, 25, 36, or 48 lines of text in 80 or 132 columns.
There are two connectors on the rear of the terminal, for connecting theVT420 to one or two host computer systems. You can also use one of
the connectors to connect to a printer. Chapters 2 and 3 describe theterminal's connectors.
The terminal's tilt and swivel base lets you adjust the screen to theviewing angle you prefer.

1

2

A Look at the Terminal

Keyboard
The VT420 uses Digital's LK401 keyboard. The keyboard has four groupsof keys and two indicator lights. The main keypad looks similar to a
typewriter keypad. A cable connects the keyboard to the right side of theterminal.
Chapter 4 describes the LK401 keyboard.

Figure 1-1

VT420 Video Terminal

A Look at the Term inal

3Your Computer System
You can use the VT420 with one or more computer systems. You haveseveral options for connecting your terminal to a computer. You canconnect the VT420 directly to acorn puter, or indirectly through a terminal
server or modem. The system you connect to is called the host.
N onnally, the keys you type on your keyboard send information to thehost. The host stores the information and displays it on the terminal's
screen. You can print the data by sending it to a printer connected to theterminal.
You can use the VT420 with the application software on your host. For
example, your host may have applications that let you do word processing,data entry, or programming.

Features
With a VT420, you can•

Select operating features from the keyboard.

•

Use two computer sessions on one terminal.

•

Display information from two sessions at the same time. You canselect two windows from the keyboard.

•

Copy information from one session to another session.

•

Display 24, 25, 36, or 48 lines of text in 80 or 132 columns.

•

Store d~ta locally in page memory for display.

•

Store frequently used commands and text in macros.

•

Fill the screen with a dark or light background for viewing comfort.

•

Align the screen.

•

Check the terminal's operating status.

Set-UpSet-up is a series of display screens that let you examine and change
the terminal's operating features from the keyboard. Each screen lists a
particular set of operating features for the terminal. For example, one
set-up screen lists communication features, while another lists keyboard
features.

4

A Look at the Terminal

Some features are for your convenience, and some are required by yourhost computer system. Each set-up feature has a factory-default setting.
You ca~ select the settings that are right for your system.
Chapter 5 describes set-up in detail.

Two SeSSions
When you use the terminal to communicate with a computer system, youhave established a session on that system. The VT420 lets you establish
two sessions and display data from both sessions at the same time. You
can connect the terminal to two different systems, depending on yourinstallation (Chap~er 2).
Here are some important tools you use to select and run two sessions:

Terminal comm ports set-up feature
SSU Enable command
Windows~ (Session) key .
The procedure for selecting and running two sessions is simple. Here are
the basic steps:
1.

Set the terminal comm ports feature to match your cableconnections to the host system.

2.

Use the ~ key or the SSU Enable command to initiate two sessions.

3.

Press the ICtr11 ~ keys to select two windows.

4.

U se ~ to easily switch back and forth between two sessions.

Chapter 3 provides the detailed procedures for setting up your tenninal to
run two sessions. Chapter 7 describes how to use two sessions.

Windows
You can divide your screen into two windows. With windows, you can see
information from two sessions at the same time. There are two styles ofwindows, full screen and split screen. The default is a full-screen window.
To change the window style, you simply press the ICtrlj ~ key combination.
When you divide the screen into two windows, you can adjust theirrelative size by moving the border between them up or down. Chapter 7
describes how to use windows.

A Look at the Terminal

5

Number of Lines on the Screen
The VT420 lets you select a font size to display 24, 36, or 48 lines on thescreen. You use the lines/screen feature to select the number of display
lines. Chapter 7 describes how to select the number of lines/screen.

Page Memory
The VT420 has off-screen memory to store data entered from the keyboard
or host system. The VT420 can store 144 lines of text.
The terminal's memory is called page memory, because you can divide the144 lines into a different number of pages. By default, the terminal uses
6 pages of 24 lines each. If you run two sessions, the default format foreach session is 3 pages of 24 lines.
Pages create boundaries that affect the way the VT420 displays text.
To take advantage of page memory, your applications must be able torecognize these page boundaries.
See the page arrangement feature in the "Display Set-Up Screen"
section of Chapter 5.

Copy and Paste
The VT420 has a copy and paste feature that lets you copy information
displayed on the screen and send it to the host system. You can send thecopied text to the same session or to another session.
Chapter 7 describes how to copy and paste text.

Status LineThe VT420 displays a status line at the bottom of the screen. If you arerunning two sessions, the terminal displays a separate status line at thebottom of each session. The status line has several fields that provide
information about the terminal's operating status. For example, one fieldshows you the current position of the cursor as a set of screen coordinates(row and column number). Applications may also use the status line tosend you messages.
Chapter 4 describes the status line.

6

A Look at the Terminal

Keyboard Indicator LineThe VT420 also displays a keyboard indicator line at the bottom of thescreen, below the status line. This indicator line has several fields thatprovide information about the keyboard's operating status. For example,
the first field indicates which session you can edit from the keyboard.
Other fields indicate if screen data is on hold, if the Caps Lock or Shift
Lock setting is in effect, if a compose sequence is in progress, or if you
must wait before entering more keyboard data.
Chapter 4 describes the keyboard indicator line.

Screen Alignment
The screen align feature on the Set-Up Directory screen lets you adjust
the position of the text on your screen for your viewing comfort. If thetext is not centered on the screen, you can center it.
Chapter 5 describes the screen alignment feature.

Screen Background
The VT420 lets you select a screen background to improve the readabilityof text on the screen. The lightJdark screen feature in the Display
Set-U p screen (Chapter 5) uses an' overscan method to fill the screen
background.

Emulating VT Series Text Terminals
The VT420 can operate like other VT series text terminals. Thisfeature enables software to recognize the terminal and select the correctemulation automatically. The VT420 can emulate the following text
terminals:
VT300 series

VT200 series

VT100 series

VT52

To have the VT420 emulate another terminal, you use two features in the
General Set-Up screen.
•

The terminal mode feature chooses an emulation mode to.matchthe software application. The VT420 is compatible with the VT220
and VT320 text terminals, so you should use the VT400 mode setting
to emulate these terminals. Other text terminals have their own
selections.

A Look at the Terminal•

7

The terminal ID feature has settings to match the terminal that uses
the software application. This feature makes the VT420 identify itself
to the host as the terminal you wish to emulate.

Chapter 5 describes the General Set-Up screen.

Character Sets
The VT420 uses coded character sets to exchange information with a hostsystem. A coded character set is a group of graphic symbols, such as
letters and numbers, represented by unique bit combinations or codes.
From the General Set-Up screen, you can choose different character sets
to match your computer system or to meet your software application
requirements. The VT420 has two 8-bit multinational sets, the DEC
Multinational character set and the ISO Latin Alphabet No. 1 characterset. The VT420 also has the DEC Technical character set for certain
applications.
DEC Multinational Character Set

The VT420 is initially set to use the DEC Multinational characterset. This 8-bit character set contains the standard characters for the
English language, plus many characters used by major Western European
languages.
ISO Latin Alphabet No. 1 Character Set

You can also select the ISO Latin Alphabet No. 1 (ISO Latin-l) characterset of the International Organization for Standardization (ISO). The ISO
Latin-l set is similar to the DEC Multinational set, but it is newer andhas more characters.
Digital recommends using the ISO Latin-l set for most applications.
However, if you use the DEC Multinational set, many applications will be
unaffected by the differences between the two character sets. Refer to theVT420 Programmer Reference Manual for detailed information about thetwo character sets.
Selecting the Character Set

You can select the DEC Multinational or ISO Latin-l character set fromthe General Set-Up screen.
Chapter 5 describes the General Set-Up and Keyboard Set-Up screens.
Chapter 9 shows the character sets.

8 A Look at the Terminal

Programming the Terminal
The VT420 Programmer Reference Manual explains the control functions
used to access the terminal's features. Programmers use these functionsin their applications. The programmer reference manual is intended forusers with programming experience.
Chapter 9 of this user guide is a summary of the control functions
and commands described in the programmer reference manual. See
Appendix B for information on how to order the VT420 Programmer
Reference Manual.

Installing Your
VT420 Video Terminal

Host orTerminal
Server

DEC-423(Comm1 )One Session

Host orTerminal
Server

DEC-423(Comm2 or
Printer)DEC-423(Comm1)
Two Sessions (2 Cables)

Host with
SSU orTerminal
Server withSSU

DEC-423(Comm1)

Two Sessions with SSU (1 Cable)

10This chapter provides step-by-step instructions to install your VT420
terminal.

Complete all the steps in order. Then go to Chapter 3 to set up theterminal for operation.

Site Considerations
The VT420 lets you run one or two sessions on a host computer system.
A session is an active connection to a computer. For example, when you
log into a system, you are running a session. The VT420 lets you run two
sessions on the same host system or on separate systems.

CablesYou need a separate communication cable for each session, unless yoursystem has Digital's Session Support Utility software or a DECserver 200
or DECserver 300 terminal server. If you use SSU software or one of the
DECservers, you only need one communication cable to run two sessions.
Appendix C shows the communication cables you can use. To order cables,
see Appendix B.
This chapter shows you how to install communication cables. Chapter 3
describes how to set up the VT420 for one or two sessions. Chapter 7
describes how to use two sessions.

11

12

Installation

Installation
Unpack and check the contents of each carton.
Make sure you have all the items shown in the following figure. If you
have missing or damaged items, contact your sales representative anddelivery agent.

o_~o VT420 video terminal with power cord attached@ Tilt-swivel base

8 Keyboard legend stripo Installing and Using the VT420 Video Terminal (North American
Model)o Cable adapter (6-pin DEC-423 to 25-pin RS-232)
o Communication cable
G LK401 keyboard

Installation

13

Install the tilt-swivel base on the terminal.
1.

Place the terminal upside down on a level surface.

2.

Position the tilt ball over the terminal so the four tabs on the ballalign with the holes on the bottom of the terminal.

3. Place the tabs in the holes.
4. Slide the tilt-swivel assembly to the left, until the assembly snaps into
place.

14

Installation

Place the terminal on a level surface.
CAUTION

Do not place objects on top of the terminal. They may block thecooling vents, causing the terminal to overheat.

Connect the keyboard to the terminal.
1.

The keyboard cable is already connected to the rear of the keyboard.
If you want the keyboard cable routed to the right or left, press thecable into one of the grooves on the bottom of the keybmtrd.
2. Insert the other end of the cable into the keyboard connector on theside of the terminal.
3. Lower the legs on the bottom of the keyboard.

Installation

Install the legend strip.
Place the legend strip between the main keypad keys and the top-row
function keys. Align the strip with the tabs.

Make sure the power switch is in the off (0) position.

15

16

Installation

Plug the power cord into the wall outlet.
Use a 120 Vac power source.

Start up your terminal.
1.

2. Make sure the keyboard lights turn on and off. The screen displays
patterns for 10 seconds. Do not press any keys during this time.
3. Wait for a bell tone from the keyboard and the VT420 OK message toappear on the screen.
NOTE

If you have problems, see the "Problem Solving" section at the endof this chapter.

Installation

17

Adjust the brightness and contrast controls for your viewing
preference.

)o Contrast control@ Brightness control

Adjust the tilt-swivel base to a comfortable viewing angle.
To set the angle, tilt the terminal forward or backward to the desired
position. You can turn the terminal to any viewing position.
CAUTION

The terminal does not swivel in a complete circle. If you try toswivel the terminal in a complete circle, you may damage the
base.

18

Installation

Cable Connections
Identify the cable connectors.
The next four pages show you how to connect the cable(s) from your hostsystem. Use the following figure to identify the cable connectors.

t1

Comm1 Port
6-Pin, DEC-423
Connector

Power
Cord

Comm2 Port
6-Pin, DEC-423
Connector(Also, Printer Port)GSF _115S_S9,DG

Port

Connector

FunctionComml6-pin, DEC-423

Connects the VT420 to a primary host computer,directly or indirectly (through a terminal server ormodem).

Comm2

6-pin, DEC-423

Connects the VT420 to a printer or a secondary
host computer, directly or indirectly (through aterminal server).

Connect your communication cable(s) to the rear of theterminal.
You have three cabling options, based on how many sessions you want to
use.
•
•

One session (one cable)• Two sessions (two cables)
Two sessions with SSU software or a DECserver 200 or DECserver
300 (one cable)

Installation

19

One Session (One Cable)
To run one session on the VT420:,.

Connect a DEC-423 cable to the 6-pin Comml connector.

oaF _,11'_' •. 00

IMPORTANT

After you install the Vl'420, you must set the terminal's operating
features to match this cable connection. Chapter 3 shows youwhat features to set.
Now, go to Chapter 3.

20

Installation

Two Sessions (Two Cables)
To run two sessions over separate communication cables:
1.

Connect one DEC-423 cable to the 6-pin Comml connector. Use thisport to connect to the primary host computer.
and2.

Connect a second DEC-423 cable to the 6-pin Comm2 connector. Use
this port to connect to the secondary host computer.

NOTE

You can also use the Comm2 port to connect a printer to theterminal. See Chapter 8.

IMPORTANT

After you install the VT420, you must set the terminal's operating
features to match this cable connection. Chapter 3 shows youwhat features to set.
Now, go to Chapter 3.

Installation21

Two Sessions with SSU Software (One Cable)
Check with your system manager to see if your host system supports SSU
software. If your host does not support SSU software or it does not use a
DECserver 200 or DECserver 300 terminal server, you need two cables to
run two sessions.
To run two SSU sessions over one cable:•

Connect a DEC-423 cable to the 6-pin Comm! connector.

IMPORTANT

After you ins~ll the VT420, you must set the terminal's operating
features to match this cable connection. Chapter 3 shows youwhat features to set.

You have installed your VT420 successfully. Go to Chapter 3.
If the screen's text is not balanced on the left, right, top, and bottom
margins, use the screen align feature in the Set-Up Directory screen(Chapter 5).

22 Installation

Problem Solving
Problem

Suggested Solution

The screen is blank.

Turn up the brightness and contrast controls.

The screen is blankand the screen saver
indicator is on.

The terminal has a CRT saver that turns off thescreen display if you do not use the terminal for
30 minutes. Press any key to reactivate the screen
display.

The bell tone does notsound when you turnthe terminal on. The
keyboard indicatorlights do not flash.

Make sure the keyboard is connected to the terminal.

Any message otherthan VT420 OK appearson the screen.

Call your local Digital Customer Services office forassistance. See Chapter 10.

The screen's text is notbalanced on the left
and right, or on the top
and bottom.

Align the text by using the screen align feature in
the Set.Up Directory screen (Chapter 5).

Power to the terminal
is lost, and you cannot
log into your host.
system.

When power is restored to the terminal, press the ~(Session) key first.

After you install your VT420, you must set some of the terminal's
operating features to•

Run one or two sessions with one or two cables.

This chapter provides step-by-step instructions. All other VT420
operating features are already set to a factory-default setting that works
with most Digital systems.
You may have to set some features to match your host system. For
example, the VT420 must use the same communication baud rate as yourhost system.
Also, the terminal ID must match the software running on the VT420. If
the message, unknown terminal type appears on the screen, you must set
the correct terminal ID. This chapter provides provides the instructions to•

Set the baud rate.

•

Set the correct terminal ID.

The VT420 has a series of set-up screens that list the terminal's operating
features. You can examine and change feature settings from the keyboard.
The procedures in this chapter explain how to use some set-up screens. If
you want to know more about set-up, or if you want to set a feature notcovered here, see Chapter 5.

23

24

Getting Started

Setting Up the VT420 for One or Two Sessions
The VT420 has two communication (Comm) ports that let you run one or
two sessions-the Comm1 port and the Comm2 port. These ports provide
the cable connections to your host system(s). To set up the terminal
correctly, you must know••

How many sessions you want to run-one or two.
I

Which port(s) and connectors you are using: Comm!, Comm2, or both.

If you are unsure, see the "Cable Connections" section in Chapter 2. Mter
you identify the port(s) and cables in use, go to the section that matches
your installation.
•

One session (one cable)•

Two sessions (two cables)•

Two sessions with SSU software (one cable)

Remember, the terminal must use a separate cable for each session,
unless your system has SSU software or a DECserver 200 or DECserver
300 terminal server. SSU lets you run two sessions over one cable, andthese terminal servers have SSU software.
Both the primary (Comm!) and secondary (Comm2) port have a 6-pin
DEC-423 connector. You can also use the Comm2 port to connect a local
printer to the VT420.

Setting Up for One Session (One Cable)
You only need one communication cable to run one session. You canconnect the cable to either the Comm1 or Comm2 port. Mter you connect
your cable, you must check the setting of the terminal comm ports
feature on the Global Set-Up screen. This feature assigns your session to
the Comm! or Comm2 port.
1. Press the ~ (Set-Up) key to enter set-up. The Set-Up Directory
screen appears (Figure 3-1). The cursor is on the Global field.

Getting Started

Set-Up Directorylijt'Mfll

Display

Clear Display
Default

General25

VT420 AV1.0
Comm

Clear Comm

Printer

Keyboard

Reset Session

RecallTab

Save

Scree n Align

Enable Sessions

Disable Sessions

Exit

Copyright C 1989, Digital Equipment Corporation - All Rights Reserved
1002,003

Printer: Read

Modem: DSR

Session 1

GSF_1167_89.DG

Figure 3-1
2.

Set-Up Directory

Press the IEnter Ikey. The Global Set-Up screen appears.

Global Set-Up
To Next Set-U
On Line

VT420 AV1.0

To Directory

S1 =Comm1

CRT SaverPrinter Shared.

70 Hz

1

002,003

Printer: Read

Modem: DSR

Session 1

3. The terminal comm ports feature is the second field on the secondline. There are four possible settings:

26 Getting Started

Sl=Comml (d.£au~t)
Sl=Comml,S2=Comm2
Sl=Comm2,S2=Comml
Sessions on CommlThe correct setting for your setup is the default setting of Sl=Comml.
If the setting is correct, press ~ (Set-Up) to leave set-up. You arefinished with this procedure.
If the setting is incorrect, go on to the next step.
4. Use the arrow keys to move the cursor to the field.
5. Press IEnter I until the Sl=Comml setting appears.
6. After you select the correct setting, use the arrow keys to move to the
To Directory field.
7. Press IEnter I to return to the Set-Up Directory. The cursor is on the
Global field.
8. Use the arrow keys to move to the Save field.
9. Press IEnter I to save all the current settings in each set-up screen. A
Done message appears at the bottom of the screen.
10. Press ~ (Set-Up) to leave set-up.

Setting Up for Two Sessions (Two Cables)
When you use two communication cables, you connect one cable to theterminal's Comm1 port and one cable to the Comm2 port. After youconnect your cables, you must set the terminal comm ports feature on
the Global Set-Up screen to match your cable connections. The terminalcomm ports feature assigns a session to each port.
1. Press the ~ (Set-Up) key to enter set-up. The Set-Up Directory
screen appears (Figure 3-1). The cursor is on the Global field.

2. Press the IEnter Ikey. The Global Set-Up screen appears.

Getting Started

Global Set-Up
To Next 5et-U
On Line27

VT420 AV1.0

To Directory

51 =Comm1 ,S2=Comm2

CRT Save r

Printer Shared

70 Hz

1 002,003

Printer: Read

Modem: DSR

Session 1

3. The terminal comm ports feature is the second field on the secondline. There are four possible settings:
Sl=Comml (default)
Sl=Comml,S2=Comm2
Sl=Comm2,S2=Comml
Sessions on CommlTo run two sessions over two communication cables, you can use oneof two settings:.
Sl=Comml,S2=Comm2

Assigns session 1 to the Comml port and session
2 to the Comm2 port.

Sl=Comm2,S2=Comml

Assigns session 1 to the Comm2 port and session
2 to the Comml port.

NOTE

When you connect your VT420 to two different systems, theVT420 always opens session 1 first. You should match session 1
with the computer you use most often.
If the setting is already correct, press ~ (Set-Up) to leave set-up. You

are finished with this procedure.
If the setting is incorrect, go on to the next step.
4.

Use the arrow keys to move to the field.

28

Getting Started

5.

Press IEnter I until the correct setting appears.
After you select the correct setting, use the arrow keys to move to the
To Directory field.

6.

Press IEnter I to return to the Set-Up Dire~tory.

7.

Use the arrow keys to move to the Save field.

8.

Press IEnter I to save all the current settings in each set-up screen. A
Done message appears at the bottom of the screen.

9.

Press ~ (Set-Up) to leave set-up.

When you use two .cables to run two sessions, you must set the baud ~atefor each session independently, See "Selecting the Correct Baud Rate"
later'in this chapter.
Chapter 7 describes how to use two sessions.

Setting Up for Two Sessions with SSU Software (One Cable)
If your host system has Digital's SSU software, the VT420 can run two
sessions over one communication cable. Your system manager can tell you
if your system has SSU software.
Connect the communication cable to the Comm1 port. Mter you connect
the cable, set the terminal comm ports feature on the Global Set-Up
screen to match your cable connection. The terminal comm ports
feature assigns sessions to the Comm1 port.
1.

Press the ~ (Set-Up) key to enter set-up. The Set-Up Directory
screen appears (Figure 3-1). The cursor is on the Global field.

2.

Press the IEnter Ikey. The Global Set-Up screen appears.

Getting Started

VT420 AV1.0

Global Set-Up
To Next Set-U
On Line29

To Directory

Sessions on Comm1

CRT SaverPrinter Shared

70 Hz

1 002,003

Printer: Read

Modem: DSR

Session 1

3.

The terminal comm ports feature is the second field on the secondline. There are four possible settings:
Sl=Comrnl (default)
Sl=Comrnl,S2=Comrn2
Sl=Comrn2,S2=Comml
Sessions on Comml

To assign both sessions to the Comml port, use the Sessions on Commlsetting.
If the setting is already correct, press ~ (Set-Up) to leave set-up. You
are finished with this procedure.
If the setting is incorrect, go on to the next step.

4.

Use the arrow keys to move the cursor to the field.

5.

Press IEnter! until the Sessions on Comml setting appears.
Mter you select the correct setting, use the arrow keys to move to the
To Directory field.

6.

Press IEnter! to return to the Set-Up Directory.

7. Use the arrow keys to move to the Save field.
8.

Press IEnter! to save all the current settings in each set-up screen. A
Done message appears at the bottom of the screen.

30

Getting Started

9.

Press ~ (Set~Up) to leave set-up.

Chapter 7 describes how to use two sessions.

Selecting the Correct Baud Rate
The VT420 is initially set to a baud rate of 9600. This setting works withmost Digital systems. The baud rate setting must match the baud rateof your host system. If you are unsure what baud rate your host system
uses, ask your system operator or system manager.
To set the baud rate, you use the transmit =and receive =features on
the Communications Set-Up screen.
1. Press the ~ (Set-Up) key to enter set-up. The Set-Up Directory
screen appears (Figure 3-1). The cursor is on the Global field.

2.

Use the arrow keys to move to the Comm field.

3.

Press the IEnter Ikey. The Communications Set-Up screen appears.

Communications Set-Up Comm1To Next Set-U
To Directory Transmit = 9600
XOFF at 64

8 Bits, No Parity

Data Leads Only

Receive=Transmit

1 Stop Bit

No Local Echo

Limited ,Transmit

No Auto Answerback

1 002,003

VT420 AV1.0

Answerback=Not Concealed

P,rinter: Read

Modem: DSR

Session 1

4.

Use the arrow keys to move to the Transmit = field.

5. The Transmit = field is initially set to 9600. You should use a settingthat matches your host system. There are eight possible settings.

Getting Started

31

Use the IEnter Ikey to scroll through the settings.
NOTE

Next to the transmit = feature is the receive = feature. Most
systems use the same speed to transmit and receive. The
initial setting for receive= is Receive=Transmit, so the receive
speed automatically changes to match the transmit speed you
select.
6. Mter you select the correct setting, use the arrow keys to move to the
To Directory field.
7.

Press IEnter I to return to the Set-Up Directory.

8.

Use the arrow keys to move to the Save field.

9.

Press IEnter I to save all the current settings in each set-up screen. A
Done message appears at the bottom of the screen.

10. Press ~ (Set-Up) to leave set-up.
If you plan to run two sessions with two communication cables, you must
set the baud rate for each session independently. To set the baud rate forthe second session, first set up the VT420 for two sessions ("Setting Up
for Two Sessions (Two Cables)"). After you complete all the steps in that
section, press the ~ (Session) key and repeat all the steps in this section.

Selecting the Correct TerminallD
The VT series text terminals are designed to identify themselves to thehost software upon request, so the software can automatically recognize
the terminals operating features. If your software has not been updated
recently, it may not recognize the VT420 ID response. For example, if
the message, unknown terminal type, appears on the screen, you shouldchange the terminai id feature as follows:
1.

Press the ~ (Set-Up) key to enter set-up. The Set-Up Directory
screen appears (Figure 3-1). The cursor is on the Global field.

2.

Use the arrow keys to move to the General field.

3.

Press the IEnter Ikey. The General Set-Up screen appears.

32' Getting Started

General Set-Up
To Next Set-U

VT420 AV1.0

To Directory

User Defined Keys Unlocked
Numeric Keypad

VT400 Mode, 7 Bit Controls

User Features Unlocked

Normal Cursor Keys

UPSS DEC Supplemental

VT420 10No New Line

When Available Update

1 002,003

Printer: Read

Modem: DSR

Session 1

4.

Use the arrow keys to move to the VT420 ID field.
Use the !Enter! key to scroll to the VT320 ID settings.

5. Mter you select the correct setting, use the. arrow keys to move to the
To Directory field.
6.

Press! Enter! to return to the Set-Up Directory.

7. Use the arrow keys tQ move to the Save field.
8.

Press IEnterl to save all the current settings in each set-up screen. A
Done message appears at the bottom of the screen.

9.

Press ~ (Set-Up) to leave set-up.

Using Your VT420 Video
Terminal

This chapter describes the basic function of each keyboard key andindicator. The chapter also describes the terminal status line andkeyboard indicator line that you can display on the screen. Later chaptersprovide more information on keys with special functions.
NOTE

A list of common keyboard functions appears at the end of thisguide. You can keep a copy of the list near the terminal, as aquick-reference tool.

LK401 Keyboard
The VT420 uses the LK401 keyboard. This guide describes the standard
North AmericanlUnited Kingdom version of the LK401 keyboard. A word
processing system (WPS) version of the keyboard is available for WPS
applications.
The LK401 keyboard has four groups of keys and two indicator lights.
The keys are grouped by function.
Main keypad
Editing keypad
Numeric keypadTop-row function keys

35

36

The Keyboard and Indicators

The LK401 keyboard also has two audible indicators,. a keyclick and bell.

Top-Row Function Keys.

Visual Indicators~Iiicll.

,:c:::> c:::>10J ~EJEJEJEJ[]~EJD[]~[]DtJ~[]Dn,.

DO
Main Keypad

Editing
KeypadNumeric
Keypad
GSF _o627 _89.DG

Main Keypad
The layout of the main keypad is similar to a typewriter keyboard, withalphanumeric characters, punctuation marks, and IShiftl keys. The main
~ad also has a number of keys not found on a typewriter, such as the~ modifier key and the I Compose Character Iprefix keys.
Modifier keys are pressed in combination with another key, to modify thecode sent by that key. Prefix keys are pressed and released before pressing
another key, to change the function of one or more keystrokes.

To use the £ symbol, you -select the British Keyboard setting in the
Keyboard Set-Up screen. To use the # symbol, you select the North
American Keyboard setting.

The Keyboard and Indicators 37

Special-Function Keys
The main keypad has the following special-function keys:
ITabl

Pressing ITabl sends a horizontal tab, which normally moves
the cursor to the next tab stop. You can select the tab stops
on the Tab Set-Up screen (Chapter 5). Applications canalso change tab stops.
Holding down ICtril and pressing another key sends a control
code to the host.
For example, ICtrl I
the [Ijkey.

W means to hold down ICtrll and press

Pressing the lock key down puts the keyboard in caps lockmode or shift lock mode. You can select the mode from
Keyboard Set-Up screen (Chapter 5). The default setting is
caps lock mode.
•

In caps lock mode, the alphabetic keys send their
uppercase or shifted character when pressed alone.
You can use a IShiftl key to send the shifted characteron other keys. You turn caps lock mode on and off bypressing and releasing the lock key.

•

In shift lock mode, all keys on the main keypad send
their shifted character. You can turn shift lock mode on
by pressing the lock kjY.
can turn it off by pressing
either the lock key or Shift key.

IOU

38

The Keyboard and Indicators

When the lock key is down, the lock indicator turns on andthe lock symbol (or the word Lock) appears on the keyboard
indicator line.
IShift!

(left andright)I Return

I

Holding down IShiftl and pressing a standard key sends theshifted (top) character on the key.
Holding down 'Shift! and pressing a special-function key
starts a predefined control function. For example, IShift!
~ (Print) means to hold down 'Shiftl while pressing the ~(Print) key.
Pressing '~R-e-tu-rn--'I sends either a carriage return or a carriage
return and a line feed (selected in the General Set-Up
screen, Chapter 5).
Pressing 'Return! normally moves the cursor to thebeginning of the next line.

Q]backarrow
key

Pressing the Q] key normally sends a DEL (delete)character. Many applications use DEL to erase one
character to the left of the cursor.
You can make the Q] key send a BS (backspace) character
instead of DEL. You use the backarrow key feature in the
Keyboard Set-Up screen (Chapter 5).

Space barPressing the space bar sends an SP (space) character. You
use spaces to separate words or move the cursor forward.
These are prefix keys, used to generate characters that
do not appear as standard keys on your keyboard. See
Chapter 6.

You use , Alt Function! with other keys, to select alternate
functions defined by your application software. The
I Alt Function Ikeys send unique function sequences tothe host, when they are pressed or released. For more
information, see the VT420 Programmer Reference Manual.

The Keyboard and Indicators

39

Editing Keypad
The editing keypad has four arrow keys and six editing keys.
Pressing an arrow key normally moves the cursor in the direction of thearrow. For example, pressing the
key moves the cursor down one line.

1IJ

You can use the editing keys in several ways.
•

For set-up functions (Chapter 5)•

For copying and pasting text between sessions (Chapter 7)•

For panning up or down on a page, or for changing the size of awindow on the screen (Chapter 7)•

For special functions defined by application software

40

The Keyboard and Indicators

Numeric Keypad
NUmeric keypad keys often have 'functions assigned by application
software, especially IPF11 to IPF41. See your application software manuals
for information about those keys.
.
You can use the numeric keypad to enter numeric data as you wouldwith a calculator. Programmers can use this keypad to do hexadecimalcompose sequences. See "Hexadecimal Compose Sequences" at the end ofChapter 6.

The IEnter I key on the numeric keypad has several
functions.
•

Normally, IEnter Iworks like the IReturn I key. IEnter I
sends a carriage return, or a carriage return and aline feed (Keyboard Set-Up, Chapter 5).

•

In set-up, you can use IEnterl to select features in
set-up screens (Chapter 5).

Application software may use IEnter I as a special-function
key.

The Keyboard and Indicators 41

Top-Row Function Keys
Predefined Keys

The first five top-row keys, ~ to ~ , are predefined to perform thefollowing functions. Normally, you do not change these functions. Ifneeded, you can change the functions from the Keyboard Set-Up screen(Chapter 5).
c:::> c:::>

[OJ

Hold

Prinl

~

S.. I-Up S....ion

areak

t
I"~'

........""-_ ..-···1~~------------~-----------)BBBB 81(ESC)[IJ (Hold)

(as)

(IF)

F14

+
Do

F17

Fls

Flll

F20

IfIl

Pressing(Hold) puts the screen display on hold. This
stops the scrolling of text on the screen, for easy reading.
The hold indicator turns on and Hold appears on the
keyboard indicator line. Pressing ~ (Hold) again releases
the screen display and allows scrolling to resume.

With Two Sessions
When you run two sessions (Chapter 7),
affects the active session.

IfIl (Hold) only

42 The Keyboard and Indicators

Pressing ICtr11 IE}] (Hold) puts the screen display for theinactive session on hold. Pressing ICtr11 [II again releases thescreen display for the inactive session.
NOTE

The hold function does not work if you set the XOFF
feature to No XOFF in the Communications Set-Up
screen (Chapter 5).
~andeditingkeys

Pressing [II (Hold) with specific keys on the editing'keypadperforms the copy and paste operation. See "Copying andPasting Text" in Chapter 7.

~

Pressing ~ (Print) sends a page of text from the current
session to the printer connected to rear of the VT420. The
terminal sends the page that contains the cursor.

(Print)A page mayor may not correspond to the screen

display.
This depends on the set-up settings for page size, font size,and page coupling features, as well as the size of the screen
window for the current session. You can change the page
size and other features from the Display Set-Up screen(Chapter 5).
ICtr11 ~ (Print) turns auto print mode on or off. In auto printmode, you can automatically print each line of text as it isreceived from the host system. See "Selecting a Print Mode"in Chapter 8.

~(Set-Up)

You press ~ (Set-Up) to enter or leave set-up. When you
enter set-up, the terminal displays the Set-Up Directory
screen. You can leave set-up from any set-up screen.
Chapter 5 describes set-up.
Pressing ICtr11 ~ (Set-Up) while in set-up causes the terminal
to perform a power-up reset. This resets many set-up
features for both sessions to their saved settings.
For more information, see the reset to initial state (RIS)
function in the VT420 Programmer Reference Manual.

The Keyboard and Indicators~(Session)

43

Pressing ~ (Session) changes the active session when you
use two sessions. You can switch from session 1 to session 2,
or from session 2 to session 1.
~ (Session) does not work when•

You are using set-up.

•·The F4 =feature (Keyboard Set-Up screen) is set to F4 =Ignore.

•

The use of two sessions has not been enabled in Global
Set-Up, by using the Sl=Comml setting.

Pressing letr" ~ (Session) lets you divide the screen into two
windows. Windows let you display two sessions at one time.
Pressing letr" ~ (Session):•

One time gives you two windows.

•

A second time returns you to a full-screen display. The
terminal only displays the active session.

See "Window~" in Chapter 7.

~(Break)Pressing ~ (Break) generates a break signal on thecommunication port associated with the current session.
Some communication equipment recognizes break as a
special attention signal. See your communication equipment
manual for details.
Pressing IShiftl ~ (Break) performs a disconnect on the serial
communication port associated with the current session. A
disconnect normally ends communication with a modem toprepare for another call.
Pressing letrl\ ~ (Break) sends the answerback message
to the active session. See the Keyboard Set-Up screen in
Chapter 5.
NOTE

letrll ~ (Break) sends the answerback message even

if you set the conceal answerback message feature in
the Communications Set..Up screen (Chapter 5).

44

The Keyboard and Indicators

User-Defined Keys and Application-Specific Keys
The function of the remaining top-row keys (~to IF201) often depends on
your application software. Refer to your application software manuals fora description of key functions. You can also. define the function of thesekeys yourself.
~ toWhen pressed alone, these keys send predefined
jF201
programming sequences to the host system (Chapter 9).
Applications that recognize these sequences can use the keys
to perform various functions.

In VT100 and VT52 modes
Keys IF111 , 1F121 , and IF131 send control characters ESC, BS,
and LF respectively. Keys ~ to jF1 01and IF141 to jF201 do not
function.
NOTE

In VT400 mode, you can use the c:J key to send the
ESC character. See the Keyboard Set-Up screen in
Chapter 5.
User-defined keys (UDKs)
Pressing IShift Iand one of these keys sends the user-defined. function for that key. You can define keys ~ to IF201 byusing programming sequences. You can use any sequenceof characters in your definitions. Definitions are loaded
from the host system. See the VT420 Programmer Reference
Manual for details.

Compose Characters
You can type compose sequences to display many more characters thanthose shown on the keycaps. For example, you can display accented
letters. Chapter 6 describes how to use compose sequences.

Indicator Lights
The keyboard has two indicator'lights, Hold and Lock. When they are
activated, Hold and Lock appear on the keyboard indicator line.

f.TI (Hold) key.

[0]

Turns on or off when you press the~Turns on or off when you press the lock key.

The Keyboard and Indicators 45

Audible Indicators
The keyboard has two audible indicators, a keyclick and a bell. You can
use a margin bell, warning bell, or both. You select the keyclick and bellsetting from the Keyboard Set-Up screen (Chapter 5).

Keyclick
You hear the keyclick sound each time you press a key that sends acode or causes the terminal to take some immediate action. If a key is
autorepeating, the keyclick will repeat once for each character or key
sequence sent. Keys· do not click under the following conditions:•

You press IShiftl or ICtrlj. These keys never click except when IShiftl isleaving the shift-lock state.

•

You select Keyclick Off in the Keyboard Set-Up screen.

•

You press a key or key combination that does not have a function
under the current operating conditions. Examples: ~ to IF10\ in
VT100 mode; invalid control combinations; and keys that generate
8-bit codes, when you use 7-bit national replacements character sets.

•

The keyboard Wait indicator is on. The terminal is net accepting
keystrokes because the host has reset keyboard action mode, or sent
XOFF to the terminal and the keyboard input silo is full. You canmanually clear the wait condition by selecting Clear Comm in the
Set-U p Directory screen.

BellThe bell tone is a beeping sound. You can use the bell as a margin bell,
warning bell, or both.
Margin Bell

This bell sounds when the cursor is eight characters from the rightmargin.
Warning Bell

This bell sounds for any of the following conditions:•

During the power-up self-test•

When the terminal receives a bell (BEL) character from the hostsystem46

The Keyboard and Indicators•

Mter a com pose character error•

When SSU errors occur (The bell rings twice.)•

If an NVR error message appears at the bottom of the screen(See Table 4-2.)

Keyboard Indicator LineThe keyboard indicator line appears at the bottom of the screen, below
the status line. When you use two sessions, there is only one keyboard
indicator line for both sessions.
.
The keyboard indicator line displays text in the smaller, 132-column fontand appears in the same video background as the main display.
Keyboard Indicator Line Fields

The keyboard indicator line has six fields that show you:••••

Which session the keyboard is connected to (the active session)
Whether or not the inactive session has been updated
When the screen is on hold or in a wait state
When the ~ (Hold) , I Compose Character I, or lock keys are active

Table 4-1 describes each field.

GoeoSession 1

Table 4-1

Copy

Hold

Lock

Composeo

Walt

Keyboard Indicator Line Fields

Field Value

IndicatesoActive session
Session 1

Session 1 is active.

Session 2

Session 2 is active.

Inactive session activity*
SessionII

Session 1 is active. Session 2's page memory is being
updated since it was last active.

*Tbis field appears in reverse video of the keyboard indicator line.

The Keyboard and Indicators 47

Table 4-1 (Cont.)
Field Value
SessionKeyboard Indicator Line Fields
Indicates

II

Session 2 is active. Session 1's page memory is being
updated since it was last active.

@

Copy

A copy and paste operation is in progress.

0
0

Hold

The screen is on hold.

Lock

Caps-Lock or Shift-Lock in the Keyboard Set-Up
screen is in effect.

"

ComposeA compose sequence is in progress.

Wait

The keyboard is in a wait state and unable to accept
typed keystrokes.

0

Status LineThe VT420 screen normally displays a status line that provides
information about the terminal's current operations. If you are runningone session, the status line appears at the bottom of the screen. If you
run two sessions, a separate status line appears at the bottom of eachsession. By default, the status line appears in reverse video .
.You can select when to display the status line. You can also let hostapplications write messages on the status line. To make these selections,
you use the status display feature in the Display Set-Up screen(Chapter 5).
The status display feature has three settings.
Indicator status
display (default)

The status line appears at all times, providing
information on the session (Table 4-2).

No status display

The status line appears when

Host-writablestatus display•

You select a set-up screen, or•

The host system selects the status line.

Applications can write messages on the status line.

NOTE

The VT420 uses separate set-up settings for each session. Anychanges you make only apply to the session you are in. If you

48

The Keyboard and Indicators

want to change a set-up setting for two sessions, you must makethe change in each session.
Status Line Fields

The default status line has four fields that show you:••••

The page number of the page displayed
Cursor position
Printer status
Modem status

Table 4-2 describes each field. When you select a host-writable statusline, applications on your host system can use the status line to send you
messages ..
You can display the status line in English, French, or German. Use the
set-up language feature in the -Set-Up Directory screen to select the
dialect.

o00
1Table 4-2
Field

002,003

Printer: Read

Modem: DSR

Status Line Fields

Value

0

Indicates
Page displayed on screen (from page memory)

1

Page 1

2

Page 2

3

Page 3

4

Page 4*

5

Page 5"

6

Page 6*
Cursor position(X,y)

Text cursor position"These page numbers never appear when you use two sessions. Each session can only use
three pages.

The Keyboard and Indicators

Table 4-2 (Cent.)
Field

49

Status Line Fields

Value

Indicates=row (1 to 144).
y =column (1 to 132).

x

You can use the 80/132 column mode feature in the
Display Set-Up screen to select 80 or 132 columns.
Printer status
Printer:Ready

The printer can receive data for printing (on-line).

Printer: Not
Ready

The printer is not ready to receive data for printing(off-line).

Printer; None

The printer is off or not connected to the VT420.

Printer: Auto
Print

The VT420 is in auto print mode. The terminal sends
the current display line to the printer when the
cursor moves to the next line.
To select auto print mode, press ICtr11 ~ (Print). See
Chapter 8.

Printer:
Controller

The VT420 is in printer controller mode. You cannot
select this mode from the terminal. The host systemselects printer controller mode.

Printer: Busy

The printer is busy printing data from the othersession.

Printer:
Assigned
to 1 (or 2)

The printer is assigned to the other session.

NOTE
Use the printer assignment feature in the Global Set-Up screen to assign
the printer.

oModem status
Modem: DSR

There is a call connected on the modem.

Modem: No
DSR

The terminal can send commands to the modem, butthere is no call connected.

50

The Keyboard and Indicators

Word Processing Keyboard
The VT420 is also available in a word processing model The keys arelabeled with word processing functions. Remember that the actual
function of the key depends on the software you use.

,."

1.., 1'",..,_w.,.,~

""2

,.,,~

,.".

ITob
II .... 'I'.·l .....
,.... . 1:"

..__

r ••,

,

~

<>

I~-"i-o'-Overview
The VT420 has nine set-up screens that list the settings for the terminal's
operating features.
Set-Up Directory
GlobalDisplay

GeneralCommunications
Printer

Keyboard
Tab
ScreenYou can display these screens and change the settings from the keyboard.
This chapter describes set-up and how to use it.
Most set-up features are initially set to a factory-default setting thatworks with many Digital systems. The VT420 has the factory-default
settings permanently stored. If you change settings, you can use the
Set-Up Directory to reset the terminal to the factory-default settings.
You can also select and save settings to match your host system. The
VT420 saves your selections in nonvolatile memory, along with thefactory-default settings. When you shut power off, you do not lose yoursaved settings.
You can make all changes to set-up features from your keyboard. Also,
your host system can change some settings, as described in the VT420
Programmer Reference Manual. See Appendix B to order VT420 manuals.

51

52

Using Set-Up

Independent Setups for Two Sessions
The VT420 can run two sessions with the host system at the same time.
Chapters 2 and 3 explain how to set up the terminal to run two sessions.
When you use two sessions, the terminal stores a separate group offeatures for each session. Only one session is active at a time. The
terminal uses the settings for the active session.
If you forget which session is active, you can check the keyboard indicatorline at the bottom of the screen. See the "Keyboard Indicator Line" sectionin Chapter 4.
NOTE

You cannot switch sessions in set-up. To switch sessions, you mustleave set-up and press the ~ (Session) key.

II--. Session(1 r 2)
Active0II -Ic:==;l'fi~\

Session 2
Current
Settings

Session 1
Curre nt
Setti ngsttYour Saved
Settings for
Session 1

Your Saved
Settings for'Session2 ..

Factory,>
Default .....••
Setti n9.s .>oNonvolatile Memory

Using Set-Up

53

Entering and Leaving Set-Up
To enter set-up: You press the ~ (Set-Up) key. When you press~ (Set-Up), infonnation on the screen disappears. (This information
reappears when you leave set-up.) Then the terminal displays the Set-Up
Directory screen.
The Set-Up Directory lists all other set-up screens. You can select anyother set-up screen from the Set-Up Directory.
TO leave set-up: You press ~ (Set-Up) again. You can leave set-up fromany set-up screen.
NOTE

Most settings that you change take effect when you leave set-up.

Set-Up Directory
When you enter set-up, the Set-Up Directory is always the first screen to
appear. You can select any set-up screen from the Set-Up Directory. You
can also perfonn such functions as saving and recalling feature settings.

VT420 AV1.0

Set-Up Directoryl§lfflMlI

Display

Clear Display
Default

GeneralClear Comm

Comm

Printer

Reset Session

Keyboard
RecallTab

Save

Screen Align

Enable Sessions

Disable Sessions

Exit

Copyright C 1989, Digital Equipment Corporation - All Rights Reserved

1 002,003

Printer: Read

Modem: OSR

Session 1

GSF_1167_89.DG

54

Using Set-Up

Status Line and Keyboard Indicator LineIn set-up, the VT420· always displays the status line and the keyboard
indicator line for the active session. Both lines appear at the bottom of
the screen. The keyboard indicator line is in the smaller, 132-column fontand appears below the status line. The keyboard indicator line is in thesame video background as the session at the bottom of the screen. For
more information, see the "Keyboard Indicator Line" and "Status Line"sections in Chapter 4.

Set-Up Cursor
Set-Up uses a field cursor that highlights a screen entry, or field, inreverse video. When you enter set-up, the field cursor highlights the
Global field in the Set-Up Directory.
You use the arrow keys to move the field cursor to different features.

Action Fields
Most features in the Set-Up Directory are action fields. When you selectan action field, the terminal immediately performs that action. You pressthe IEnter I key to select the action field highlighted by the cursor. Most
set-up screens have some action fields.
Some actions do not affect the screen, so the VT420 displays a message tolet you know if the action was successful. This message appears in placeof the keyboard indicator line at the bottom of the screen.
•

A Done message indicates the action is complete. The message
disappears when you press another key.

•

An error message indicates the terminal could not perform the action.

See Table 10-2.
TheVT420 displays messages for the following action fields on the Set-Up
Directory screen:
Clear Display
Clear Comm
Reset Session
Recall (saved settings)

Save (settings)
Default (recall factory settings)
Enable Sessions
Disable Sessions

Using Set-Up

55

Set-Up Directory Fields
Table 5-1 describes the Set-Up Directory features.
Table 5-1

Set-Up Directory Features

FeatureDescription

GlobalDisplay
GeneralComm
Printer
Keyboard
Tab

These fields select the set-up screen. For example,
Global selects the Global Set-Up screen.

Clear Display

Clears the screen when you leave set-up.

Clear Comm

Clears communications for the active session. Clear
Comm does not affect the on-linellocal state, but does
the following:•Stops any print operation.

~

Stops any escape sequence, control sequence, control
string, or character string processing (ESC, CSI,
DCS, APC, OSC, PM, SOS).

•

Clears the keyboard buffers.

•

Clears the receive buffer.

•

Clears the transmit buffer.

•

Stops printer controller mode and returns to normal
print mode.

•

Sends an XO N signal to the host.

•Sends an XON signal to the printer if the printerto host and XOFF features are enabled in the
Printer Set-Up screen (Chapter 8).

•

Resets the XOFF received flags at the printer andhost ports.

56

Using Set-Up

Table 5-1 (Cont.)
FeatureReset Session

Set-Up Directory Features
Description•

Does not clear the screen.

•

Clears a keyboard wait condition.

•

Clears the "printer port has seen DSR since powerup" flag.

Resets many VT420 operating features for the active
session to their initial state.
The screen, communication, character set modes, anduser-defined keys are not affected. See the VT420
Programmer Reference Manual.

RecallSets all set-up features for the active session to their
saved values. Clears the screen.

NOTE

If you are using a modem, Recall disconnects communication with thehost system.
Save

Saves all current feature settings in all set-up screens
for the active session.

Default

Replaces all current settings in all set-up screens withthe factory-default settings. This feature may affect bothsessions, because the default session configuration is one
session.
The default feature also:•

Clears the screen and returns the cursor to theupper-left corner.

•

Stops any print operation.

•

Stops any escape sequence, control sequence, control
string, or character string processing (ESC, CSI,
DCS, APC, OSC, PM, SOS).

NOTE
If you are using a modem, Default disconnects communication with thehost system.

Using Set-Up

Table 5-1 (Cont.)

57

Set-Up Directory Features

FeatureDescription

Screen AlignLets you center or rotate the image on the screen. Thisfeature clears the screen and creates a black borderaround the screen's perimeter. The text area of thescreen appears in reverse video from the border.
After you select this feature, follow the directions on thescreen to align the image correctly.

Enable Sessions

Lets you resume an interrupted session. A session canbe interrupted by a power failure to the terminal or host.
To use this feature, your system must have SSU
software. Also, you must set the terminal commports feature in the Global Set-Up screen to Sessions
on Comml.

When you select this feature, one of the following
messages on the status line:
•

Done

•

Sessions restored•

Sessions not selected

See Chapter 7 for more information.
Disable Sessions

Disables the current SSU sessions.

Exit

Lets you leave set-up. You can also press ~ (Set-Up) toleave set-up.

Selecting Set-Up Screens
There are two ways to select set-up screens. You can move from one
screen to the next, in the same order listed on the Set-Up Directory. You
can also select any screen directly from the Set-Up Directory.

Moving from Screen to Screen
Each set-up screen has a To Next Set-Up field. To move from one screen
to the next:1.

Use the arrow keys to move the cursor to To Next Set-Up.

58

Using Set-Up

2.

Press IEnter I.

Selecting a Screen from the Set-Up Directory

The Set-Up Directory lists all the set-up screens. To display a selected
screen:1.

Use the arrow keys to move the cursor to the name of the desired
screen.

2.

Press IEnter I.

Changing and Recalling Settings
This section describes how to change, save, and recall set-up settings.

How to Change Settings
Use the arrow keys to move the set-up cursor to a particular feature on
a setup jcreen. Most features have two or more possible settings. Use
the Enter key to change the setting of the feature highlighted by the
cursor. Each time you press IEnter I, the setting changes. Depending on thefeature, the change takes effect immediately or when you leave set-up.
ExampleThis example shows you how to change the screen display setting from 80
to 132 columns.
1.

Press ~ (Set-Up) to enter set-up. The Set-Up Directory appears. The
field cursor is on the Global field.

2.

Use the arrow keys to move to the Display field.

3.

Press IEnter I. The Display Set-Up screen appears.

4.

Use the arrow keys to move to the 80 Columns field. Press I Enter 1 tochange the setting to 132 Columns.

When you change a feature setting, the VT420 uses that setting until you
turn the terminal off or change the setting again. To save a new setting,read the next section.

Using Set-Up 59

How to Save Your Settings
If you make changes to current settings, you can save your changes
with the save feature in the Set-Up Directory. This feature saves all
current settings (in most set-up screens) for the active session. Even
after you turn off the terminal, it retains the saved settings. The VT420
automatically uses these settings each time you turn the terminal on.
ExampleThis example shows how to save the 132 columns setting selected in theprevious example.
1. Mter you select the 132 columns setting, use the arrow keys to moveto the To Directory field.
2.

Press IEnter\ to return to the Set-Up Directory screen.

3.

Use the arrow keys to move to the Save field.

4.

Press IEnter \ to save all current settings.

5.

Press ~ (Set-Up) to leave set-up.

If you change settings again, you can recall your saved settings. Read thenext section.

How to Recall Saved Settings
For some applications, you may want to make temporary, changes tocurrent settings. When you are finished using the temporary settings,
you can recall your saved settings with the recall feature in the Set-Up
Directory.
To recall saved settings:
1.

Press ~ (Set-Up). The terminal displays the Set-Up Directory.

2.

Use the arrow keys to move the cursor to the Recall field.

3.

Press IEnter\. The VT420 replaces all existing settings with thepreviously saved settings. A Done message on the status line indicatesthe action is complete.

4.

Press ~ (Set-Up) to leave set-up.

NOTE

If you are using a modem, Recall disconnects communication withthe host system.

60

Using Set-Up

Global Set-Up Screen
This screen has features that affect both sessions when you use twosessions. Table 5-2 describes each feature on the Global Set-Up screen.

Two Sessions
You use the terminal comm ports feature in Global Set-Up to set
up the VT420 for two sessions. The setting must match the system cableconnections you are using on the rear of the terminal. Chapter 3 describes
how to set up the terminal for two sessions. Chapter 7 describes how to
use two sessions.

VT420 AV1.0

Global Set-Up
To Next Set-U
On LineTo Directory
CRT Saver

S1 =Comm1

Printer Shared

70 Hz

1 002,003

Printer: Read

Modem: DSR

Session 1

Table 5-2

Global Set-Up Features

Feature and Settings

Description

On-linellocal

Selects whether or not the VT420 can communicate
with a host system.

OnLineLets the VT420 communicate with a host.

Local

Puts the host on hold. The characters you type go
directly to the screen.

Default settings are in bold type.

Using Set-Up

Table 5-2 (Cont.)

61

Global Set-Up Features

Feature and Settings

Description

Terminal comm ports

Assigns the communication connectors on the rearof the terminal to session ! or 2.

SI=Comml

Assigns only one session to the Comm! connector.
The Session indicator does not appear on the
keyboard indicator line.

Sl=Comml,S2=Comm2

Assigns session 1 to the Comml connector, andsession 2 to the Comm2 connector.

Sl=Comm2,S2=Comml

Assigns session 1 to the Comm2 connector, andsession 2 to the Comm! connector.

Sessions on Comml

Assigns both SSU sessions to the Comm! connector.
Both sessions use the same communication cable.

CRT saver

Increases screen life.

CRT SaverIf the terminal is left on but inactive for 30 minutes,
the screen goes blank. You can press any key toreactivate the screen. The host can also reactivate
the screen by sending any character.

No CRT Saver

CRT saver feature is disabled.

Printer assignment

Selects which session can use the printer port.

Printer Shared

Both sessions can use the printer port, but not at
the same time.

Printer Session 1

Only session ! can use the printer port.

Printer Session 2

Only session 2 can use the printer port.

Screen refresh rate

Sets the video refresh rate.

70Hz

This screen refresh rate is recommended in mostenvironments, to minimize flicker.

60 Hz

U sed in environments with electrical noiseinterference.

Default settings are in bold type.

62

Using Set-Up

Display Set-Up Screen
This screen has features that affect the way data appears on the screen.
Table 5-3 describes the Display Set-Up features.

Selecting a Page Size
The VT420 has page memory that can store up to 144 lines of text enteredfrom the keyboard or host system. You can divide the 144 lines into a
different number of pages, by using the page arrangement feature on
the Display Set-Up screen.
There are many page sizes available (Table 5-3). The default page size is
the same size as the default screen display area.
•

If you use one session, all 144 lines of page memory are available.
The default setting is 6 pages of 24 lines each.

•If you use two sessions, each session has 72 lines available. The
default setting for each session is 3 pages of 24 lines each.

Pages create boundaries. Before you change the standard page size of 24lines, you may want to check your application's documentation to makesure the application can recognize the new page boundaries. To display a
new page, use the ICtrlj INextl and ICtrlj IPrev\ keys.

Selecting the Number of Lines/Screen
You use the lines/screen feature on the Display Set-Up screen to selectthe number of text lines you see on the screen. The ability for the VT420
to display the selected number of lines depends on the following factors:
If ...

Then ...

The page size is less than thenumber of Lines/ Screen
displayed

The VT420 displays only the number oflines on the page.

The page size is greater than
the number of Lines/ Screen
displayed

The VT420 may display additional lines
on the screen. For example, when thestatus display feature is disabled, an
additional line of data is put in place ofthe missing status line.

Using Set-Up

63

The number of lines displayed is limitedby the screen area allocated to eachsession.

You use two windows

Coupling the Cursor to the Display
The VT420 lets you pan through the information stored on one page ormove to another page. The Display Set-Up screen has two features that
determine whether or not the display automatically pans to keep the
cursor visible: vertical coupling and page coupling. See Chapter 7 fora description of panning.

VT420 AV1.0

Display Set-Up
To Next Set-Up

To Directory

No Auto Wrap

Smooth-2 Scroll

Cursor80 Columns

Block Cursor Style

Cursor Blink

6x24 Pages

Vertical Coupling

Interpret Controls

Dark Screen
No Status Display

24 Lines/Screen

Page Coupling

1 002,003

No Auto Resize Screen

Printer: Read

Modem: DSR

Session 1

GSF _0637 _89A.DG

Table 5-3

Display Set-Up Features

Feature and Settings

Description

80/132 column mode
80 Columns
132 Columns

Selects an 80- or 132-column page width for text.
The screen display width is the same as the page
width.
If you change the current setting, page memory
clears.

Default settings are in bold type.

64

Using Set-Up

Table 5-3 (Cont.)

Display Set-Up Features

Feature and Settings

Description

Control representation
modeInterpret Controls
Display Controls

Selects whether the terminal processes (interprets)
or displays control characters. You can use thisfeature as an aid for debugging programs. See"Display Controls Mode" in the VT420 Programmer
Reference Manual.

Auto wrap

Selects whether or not text automatically wraps tothe next line when you reach the right margin.

No Auto Wrap

When you reach the margin, the VT420 displays
each new character in the last column of theline. Each new character overwrites the previous
character at that position.

Auto Wrap

When you reach the margin, the VT420 displays
new characters on the next line.

Smooth/jump scroll
Smooth·2 Scroll
Smooth-4 Scroll
Jump Scroll

When you select Smooth-2 Scroll or Smooth4 Scroll, text on the screen scrolls smoothly.
Srnooth-4 Scroll is twice as fast as Smooth-2
Scroll. When you select Jump Scroll, text on thescreen scrolls as fast as the terminal processes it.

Light/dark screen
Dark Screen
Light Screen

Selects light text on dark background, or dark text
on light background. Takes effect in set-up.

Cursor
CursorNo Cursor

Selects whether or not to display the cursor.

Cursor style
Block Cursor Style
Underline Cursor
Style

Selects a block or underline cursor.

Status display

Selects how and when to use the status line.

No Status Display

This session does not display a status line outsideof set-up.

Indicator Status
Display

The VT420 displays a status line for the current
session.

Default settings are in bold type.

Using Set-Up

Table 5-3 (Cont.)

65

Display Set-Up Features

Feature and Settings
Host Writable Status
Display

Description
The host can display information on the status line
for this session.

NOTE

In set-up, the terminal always displays the status line for the current
session.
Cursor blink
Cursor Blink
Cursor SteadySelects whether or not the cursor blinks (flashes).

Page arrangement

Selects the the number of lines/page. The effect of
this feature depends on whether you are runningone session or two sessions.

For Two Sessions
3x24

Selects 3 pages, with 24 lines/page.

2x25

Selects 2 pages, with 25 lines/page.

2x36

Selects 2 pages, with 36 lines/page.

1x48

Selects 1 page of 48 lines.

1x72

Selects 1 page of 72 lines.

For One Session
6x24

Selects 6 pages, with 24 lines/page.

5x25

Selects 5 pages, with 25 lines/page.

4x36

Selects 4: pages, with 36 lines/page.

3x48

Selects 3 pages, with 48 lines/page.

2x72

Selects 2 pages, with 72 lines/page.

1x144

Selects 1 page of 144 lines.

N umber of lines/screen *24 Lines/Screen

Selects the number of lines displayed on the screen
at one time.
Selects the 24 lines/screen font .

.. The number of lines/screen is a user preference feature. If you select the user features
locked feature in the General Set-Up screen and enable auto resize screen in the Display
Set-Up screen, then the number of lines/screen changes when the page size changes. For
more information, see "Selecting the Number of Lines/Screen" at the beginning of thissection.
Default settings are in bold type.

66

Using Set-Up

Table 5-3 (Cont.)

Display Set-Up Features

Feature and Settings

Description

36 Lines/Screen

Selects the 36 lines/screen font.

48 Lines/Screen

Selects the 48 lines/screen font.

Vertical coupling
Vertical Coupling
No Vertical Coupling

Selects whether or not to automatically pan when
the cursor moves beyond the top or bottom borderof a window. Automatic panning keeps the cursor
visible.

Page coupling
Page Coupling

Selects whether or not to automatically display a
new page when the cursor moves to a new page inpage memory. For more information, see "Windows"
in Chapter 7.

No Page Coupling

If the cursor moves to a new page, you cannot see
the page or the cursor.

NOTE
The page coupling feature is only useful when the page arrangement
feature is set to two or more pages.

Auto resize screen *~o ~uto ltesize
Screen·Auto Resize Screen

Selects whether or not to automatically change thenumber of lines/screen when the page arrangementchanges.
Resizes the screen when the page size changes.
Page size

Screen size

24 lines

24 lines
24
36
48
48
48

25
36
48

72
144

*The number of lines/screen is a user preference feature. If you select the user features
locked feature in the General Set-Up screen and enable auto resize screen in the Display
Set-Up screen, then the number of lines/screen changes when the page size changes. For
more information, see "Selecting the Number of Lines/Screen" at the beginning of thissection.
Default settings are in bold type.

Using Set-Up

67

General Set-Up Screen
This screen lets you set general features, such as the character set used
to display characters on the screen. The terminal mode feature lets
the VT420 emulate other VT series terminal for software compatipility.
Table 5-4 describes the General Set-Up features.

Character Sets
The General Set-Up screen lets you select from two multinational
character sets:.
••

DEC multinational character set
ISO Latin Alphabet No. 1 character set (International Organizationfor Standardization).

Both character sets have two parts--the U.S. ASCII character set and a
supplemental set.
•

The U.S. ASCII character set (United States American Standard Codefor Information Interchange) contains the letters and numbers forEnglish-speaking countries.

•

The supplemental character set contains additional symbols andmost characters used in the major European languages. There are
two supplemental character sets to select from-DEC Supplemental
character set and ISO Latin-l supplemental character set.

Use the UPSS (user-preferred supplemental set) feature to select the
supplemental set you prefer, DEC Supplemental or ISO Latin-I. You canenter many of the characters in a supplemental set by using compose
sequences (Chapter 6).
By default, the VT420 uses the DEC Multinational character set.

68

Using Set-Up

General Set-Up
To Next Set-U

VT420 AV1.0

To Directory

User Defined Keys Unlocked
Numeric Keypad

VT400 Mode, 7 Bit Controls

User Features Unlocked

Normal Cursor Keys

UPSS DEC Supplemental

VT420 IDNo New Line

When Available Update

Printer: Read

1 002,003

Modem: DSR

Session 1

Table 5-4

General Set-Up Features

Feature and Settings.

Description

Terminal m"ode

Selects the terminal's operating mode. The VT420
can emulate any VT series text terminal.

VT400 Mode, 7-Bit
Controls

Lets the terminal use all VT420 features. The
terminal normally uses 8-bit graphic characters and7-hit control characters. Select this mode for VT200
and VT300 applications. Digital recommends
this mode for most applications.

VT400 Mode, 8-Bit
Controls

Lets the terminal use all VT420 features. The
terminal uses 8~bit control characters. See
Chapter 9 for details. Select this mode for all
VT200 and VT300 applications that use 8-bit
control characters.
This mode is the most efficient, but not yet
supported by all applications.

VT100 ModeUse this mode for applications that require VT100
compatibility.

VT52 Mode

Lets the terminal run VT52 applications.

Default settings are in bold type.

Using Set-Up

Table 5-4 (Cont.)

69

General Set-Up Features

Feature and Settings

Description

Terminal ID

Selects the device attributes response (terminal
ID). Some applications require specific responses.
This response lets the host system know specificoperating attributes of the terminal.

VT420ID
VT100ID
VT101ID
VT102ID
VT220ID
VT320IDNOTE

If your operating system does not recognize the VT420 1D setting, selectthe VT320 1D setting (Chapter 3).

User defined keys lock
User Defined Keys
Unlocked
User Defined Keys
LockedSelects whether or not the host system can change
user-defined key CUDK) definitions.

User features locked
User Features
Unlocked
User Features Locked

Selects whether or not the host system can change
the settings of the user preference features: auto
repeat, smooth/jump scroll, light/dark screen,tab, keyboard lock, and number of lines/screen.
User preference features are intended to becontrolled by the user or terminal management
software, rather than by application software.

Keypad mode

Selects the type of characters sent by the numeric
keypad.

Numeric Keypad

The keypad sends the numbers shown on the
keycaps (using ASCII code).t

Application Keypad

The keypad sends control sequences (used withsome applications).t

Cursor key mode
Normal Cursor
Keys
Application Cursor
Keys

Selects whether the arrow keys send ANSI cursor
control sequences or application-specific control
functions. *New line

Selects how the IReturn Ikey works.

* Chapter 9 shows the VT420 character sets.
tThe setting is not saved in nonvolatile memory.
Default settings are in bold type.

70

Using Set-Up

Table 5-4 (Cont.)

General Set-Up Features

Feature and Settings

Description

No New Line

Pressing IReturn I sends a carriage return character.
The VT420 does not automatically move the cursor
to a new line.

New Line

Pressing IReturn I sends a carriage return and a line
feed. Used for some non-Digital applications.

User-preferredsupplemental set (UPSS)

When the character set mode feature is set to
8-bit Characters, this feature selects the 8-bit
supplemental character set.

UPSS DEC
Supplemental

Selects the DEC Supplemental character set, whichis part of the 8-bit DEC Multinational set. See
Chapter 9.

UPSS ISO Latin-l
Supplemental

Selects the ISO Latin-l supplemental character
set, which is part of the ISO Latin-l multinational
character set.

Update method

Selects how and when to update page memory forthe inactive session.

When Available
UpdateUpdates page memory for the other session
whenever the terminal is not busy with the active
session for one second.

Shared Update

Updates page memory for a session whenever theterminal is not busy with the other session. Neither
session has priority.

Never Update

Prevents updates to page memory for the inactive
session.

Default settings are in bold type.

Using Set-Up

71

Communications Set-Up Screen
This screen lets you set up the terminal to communicate with your hostsystem. The default settings are those commonly used on Digi tal systems.
Make sure the settings you use match the communication settings of yoursystem.
This screen also includes features for use with modems. Chapter 8 has
more information on modems.
If you use the printer connector to connect a second host system to theterminal, the Communications Set-Up screen indicates which port is in
use for the current session. The term Comrn or Prnt appears on the top lineof the set-up screen.

Table 5-5 describes the Communications Set-Up features. For more
information, see VT420 Programmer Reference Manual.

Communications Set-Up Comm1To Next Set-Up
XOFF at 64

To Directory

Transmit = 9600

8 Bits, No Parity

Data Leads Only

VT420 AV1.0
Receive=Transmit

1 Stop Bit

No Local Echo

Limited Transmit

No Auto Answerback

Answerback=1 002,003

Not Concealed

Printer: Read

Modem: DSR

Session 1

Table 5-5 Communications Set-Up Features
Feature and Settings

Description

Transmit speed
Transmit=9600

Selects the baud rate the VT420 uses to send data
to the host system. The transmit baud rates range
from 300 to 38400 bits/second. The default setting ofTransmit=9600 works with most Digital systems.

Default settings are in bold type.

72

Using Set-Up

Table 5-5 (Cont.)

Communications Set-Up Features

Feature and Settings

Description

NOTE
The terminal's transmit speed must match the host's receive speed.
However, the VT420 can transmit at one speed and receive at another.

Receive speed
Receive=Transmit

Selects the baud rate the VT420 uses to receive datafrom the host system. Receive baud rates range from
300 to 38,400 bits/second. The default setting is
Receive=Transmit.

NOTE
The terminal's receive speed must match the host's transmit speed.
However, the VT420 can receive at one speed and transmit at another.

XOFF
XOFF at 64

NoXOFF
Data bits/parity
8 Bits, No Parity

Selects the number of characters the VT420 storesin its input buffer before sending the XOFF flow
control signal. If you use one session, you can selectan XOFF point of 64 or 128. If you use two SSU
sessions, you can select an XOFF point of 64, 256, or1792 (Appendix C).
"NiH not send an XO FF signal.
Specifies the character format for communicatingwith the host system, including:•

Bits used to send each character (7 or 8)•

Parity setting: even, odd, or none•

Whether or not to check parity on received
characters at the host port

If you select a 7-bit environment for the host port,
you cannot use 8-bit character sets.
Stop bits
1 Stop Bit
2 Stop Bits

Selects the number of stop bits used by the host port.

Local echo

Selects whether or not to send the characters you
type directly to page memory.

Default settings are in bold type.

Using Set-Up

Table 5-5 (Cont.)

73

Communications Set-Up Features

Feature and Settings

Description

No Local Echo

Sen'ds keyboard data to the host system. The hostdecides whether or not to send the data back to theterminal.

Local Echo

Sends keyboard data both to the host and back to theterminal.

Modem control

Configures the terminal to work with various modem
features. See Chapter 8.

Data Leads Only

Modem control pins on the DEC-423 connector are
not used.

Modem Control

Uses DSR (pin 6) and DTR (pin 1) of the DEC-423
connector.

Transmit rate limit
Limited Transmit
Unlimited Transmit

Selects whether or not to limit the terminal tosending 150 to 180 characters/second. A limited rate
reduces the interrupt burden on the host system.

Auto answerback
No AutoAnswerback
Auto Answerback

Selects whether or not to send the answerback
message to the host system when establishing aconnection.

Answerback =Lets you type an answerback message. You can use
up to 30 characters. This prompt appears on thestatus line, indicating the start of the message. If
you press the ~ (Set-Up) key while entering ananswerback message, the VT420 deletes the newmessage and saves the old message.

Conceal answerback
Not Concealed
Concealed

Selects whether or not the VT420 will display theanswerback message.

NOTE

H the conceal answerback feature is set to Concealed, you must enter a
new answerback message before you can set it back to Not Concealed.
Default settings are in bold type.

74

Using Set-Up

Keyboard Set-Up Screen
This screen lets you control the operation of the keyboard. This includes
the function of various keys and the keyboard's keyclick, warning bell,
and margin bell.
Table 5-6 describes the Keyboard Set-Up features.

Keyboard Set-Up
To Next Set-Up
Auto Repeat
Character Mode
F1 = Hold

VT420 AV1.0

To Directory

Caps Lock

Keyclick High

Margin Bell Off

Warning Bell High<Xl Delete

Local Compose

Report Alt

F2 = Print

F3 = Set-Up" and .. Keys Send ,< and.>F4 = Session'- Key<> Key1 002,003

F5 = BreakPrinter: Read

Modem: DSR

Session 1

Table 5-6. Keyboard Set-Up Features
Feature and Settings

Description

Caps/shift lockSelects the function of the lock key in the down
position.

Caps Lock

When the lock key is down, the alphabetic keys
send their uppercase character. Other keys still
send the bottom character on their keycap.

Shift Lock

When the lock key is down, all keys send the shiftedor top character on their keycap.

Auto repeat
Auto Repeat
No Auto Repeat

Selects whether or not a key sends its character
repeatedly when you hold the key down."

I

I'"The following keys never repeat: ~ ~ B~, ~ Return I, ICtrlb Alt Function

I Compose Character l and lock.
Default settings are in bold type.

lUsing Set-Up 75

Table 5-6 (Cont.)

Keyboard Set-Up Features

Feature and Settings

Description

Keyclick
Keyclick High
Keyclick Low
Keyclick Off

Selects whether or not keys click when you .press
them. You can select a high or low volume.

Margin bell
Margin Bell Off
Margin Bell High
Margin Bell Low

Selects whether or not the VT420 bell sounds when
the text cursor approaches the right margin. You
can select a high or low volume.

Warning bell
Warning Bell HighWarning Bell Low
Warning Bell Off

Selects whether or not the VT420 bell rings when
(1) Operjtinn errors occur or (2) the terminal
receives Ctrl ~. You can select a high or low
volume.

Character mode

Selects whether the keys send their normal
characters or report their key position.

Character Mode

Selects ANSIIISO character encoding for the
keyboard.

Position Mode

The keyboard sends control strings that indicate
the position of the key pressed.

Backarrow key<KI Delete<XI Backspace
Compose key

Local Compose

Selects the function of the <XI key.

<XI sends the DEL (delete) character.
<XI sends the BS (backspace) character.
Selects the function of the I Compose Characterkeys.

I Compose Character Istarts a compose sequence(Chapter 6).

Report Compose

I Compose Character Isends a control sequence tothe host to report each down or up key transition.

Ignore Compose
Alt Function key

ReportAlt

I Compose Character Ikeys are ignored.
Selects the function of the I Alt Function Ikeys.
I Alt Function I sends a control string to the host toreport each up or down key transition.

Ignore Alt

I Alt Function Ikeys are ignored.

Default settings are in bold type.

76

Using Set-Up

Table 5-6 (Cont.)

Keyboard Set-Up Features

Feature and Settings

Description

F1 =Selects the function of the ~ (Hold) key.

Fl =Hold~ stops the scrolling of text for the active session(Cha'pter 4).

Fl = Fkey~ (unshifted) sends a function key sequence to thehost.

F1 = Ignore~ is ignored. This setting does not disable ~ fora copy.and paste operation.

F2=

F3

Selects the function of the ~ (Print) key.

F2 = Print~ performs the local print functions described in
Chapter 8.

F2 = Fkey~ (unshifted) sends a function key sequence to thehost.

F2 = Ignore~ is ignored.

=

Selects the function of the ~ (Set-Up) key.

F3 = Set-Up~ is used to enter or leave set-up.

F3 = Fkey~ (unshifted) sends a function key sequence to thehost. To enter set-up after you disable this key: log
out, turn off the terminal, wait 10 seconds, thenturn on the terminal and make ~ the first key youpress.

F3= Ignore~ is ignored.

F4 =Selects the function of the ~ (Session) key.

F4 = Session

Pressing ~ switches the active session when you
use two sessions (Chapter 8).

F4 = Fkey[8) (unshifted) sends a function key sequence to thehost.

F4 = Ignore
F5 =~ is ignored.
Selects the function of the ~ (Break) key.

F5 = Break~ (unshifted) sends a break signal.

F5 = No Break••Default settings are in bold type.

~ (unshifted) is ignored.
~ (shifted) performs a disconnect.

Using Set-Up

Table 5-6 (Cont.)

77

Keyboard Set-Up Features

Feature and Settings

Description

F5 = Fkey~ (unshifted) sends a function key sequence to thehost.

F5 = Ignore~ is ignored.
Selects the function of the shifted comma andperiod keys.

" and .. keys

" and •• Keys Send,< and.>The comma key sends a comma when unshifted anda < character when shifted. The period key sends
a period when unshifted and a > character whenshifted.

" and .. Keys

The shifted comma key sends a comma. The shifted
period key sends a period.
Selects the function of the ~ angle bracket key.

<> key<>Key~ sends a < when unshifted and a> when shifted.

<> Key Sends' ....

~ sends a' when unshifted and a .... when shifted.
Selects the function of the'- key'- Key' .... Key Sends ESC

G key.

G sends a ' when unshifted and a .... when shifted.
G sends an escape (ESC) character.

Default settings are in bold type.

Tab Set-Up Screen
This screen lets you set the number of tab stops on a line. Tab stops
on the screen are similar to tab stops on a typewriter. When you pressthe ITabl key outside of set-up, the cursor advances to the next tab stop.
Table 5-7 describes the Tab Set-Up features.
There is one tab stop field for each column on the screen. You can use ascreen display of 80 or 132 columns wide. See the 80/132 column mode
feature in the Display Set-Up screen.
You can use the arrow keys or the ITabl key to move the cursor to any tabstop field. Press the IEnter I key to place a T in a blank field or erase a Tfrom that field. The following figure shows the default tab stop settings.

NOTE
You cannot put a tab in column 1.

78

Using Set-Up

Tab Set-Up

VT420 AV1.0

To Next Set-U

To Directory

Clear all tabs

Set 8 column tabs

T
T
T
T
T
T
T
T
T
12345678901234567890123456789012345678901234567890123456789012345678901234567890

1 002,003.

Printer: Read

Modem: DSR

Session 1

Table 5-7 Tab Set-Up Features
FeatureDescription

Clear all tabs

Removes all current tab settings shown on the Tab Set-Up
screen.

Set 8 column
tabs

Automatically sets one tab every eight columns, starting atcolumn 9.

The VT420 lets you type more ch~acters than appear on your LK401
keyboard. For example, you can type accented characters or a © symbol.
This chapter lists the available characters and shows you how to selectthem.

To enter one of these characters, you type a se uence.of two or three keys.
You start each sequence by pressing the Compose Character key. There
are two types of compose key sequences:•

Three-stroke key sequences•

Hexadecimal key sequences (for programmers)

What Characters Can I Type?
You can type any of the characters from the character set the terminal
is currently using. You can select from two multinational sets-DEC
Multinational or ISO Latin Alphabet No. 1. By default, the VT420 uses
the DEC Multinational set. Chapter 1 describes the two character sets,
and Chapter 9 shows each character set.
The character set mode feature in the General Set-Up screen sets theterminal to work with 8-bit multinational sets.

79

80

Typing Additional Characters

How to Type a Character Using the Compose
Character Key
To enter a compose key sequence:
1.

Find the character you want to type in Table 6-1.

2.

Press the I Compose Character Ikey. Compose appears on the keyboard
indicator line, indicating the terminal is in the compose mode.
NOTE

If the -:C-o-m-p-o-se~C-:-h-a-ra-ct-e-r-" key does not work, check the settingof the compose key feature in the Keyboard Set-Up screen(Chapter 5).
r-"I

3.

Type the sequence in Table 6-1 for the character you want.

ExampleTo type an e:
1. Find the e character in Table 6-1.
2.

Press I Compose Character I.

3. Type [!] andD (apostrophe).

NOTE

If you try to enter a character that is not available in the current
character set, a warning bell sounds. See "Invalid Sequences" inthis chapter.

Invalid Sequences
When you complete a valid compose sequence, the selected character
appears on the screen and the Compose indicator turns off. If you use aninvalid sequence, the VT420 cancels the sequence and sounds the warningbell.
Some characters require that you type the key sequence in the ordershown in Table 6-1. If you do not follow the order, the sequence isinvalid and the warning bell sounds. If the terminal does not display
the character, repeat the sequence exactly as shown in Table 6-1.
NOTES

Pressing a function key cancels a compose sequence withoutsounding the bell.

Typing Additional Characters81

You can turn the warning bell on or off in the Keyboard Set-Up
screen (Chapter 5).

Canceling or Restarting a Compose Sequence
If ou accidentall

start a compose sequence by pressing thekey, press the <&J key. This immediately cancels
the compose sequence.
Compose CharacterIf you press I Compose Character! during a compose sequence, a new
three-stroke sequence starts from that point. The first sequence iscanceled.
If you press any of the following keys during a compose sequence, they

cancel the sequence and perform their usual function:• 'Tab!
• Any top-row key• 'Enter!

I• Any ICtr111 other key combination

Hexadecimal Compose Sequences
This feature is primarily for programmers who are familiar with character
coding and hexadecimal representation.
The VT420 uses coded character sets to exchange data with a hostcomputer. These codes can be represented by a pair of hexadecimal
digits. With the VT420, you can enter any 8-bit code by pressing the
I Compose Character Ikey followed by two hexadecimal digits typed on the
numeric keypad.
When you press I Compose Character b the terminal assigns hexadecimalvalues to the numeric keypad keys (Figure 6-1). The character set tables
in Chapter 9 show you the hexadecimal values for each character in thestandard character sets.
NOTE

The character set mode and UPSS features in the General Set-Up
screen do not affect hexadecimal compose sequences.

Examples•You can use a hexadecimal compose sequence to send the US (unitseparator) control character. The hexadecimal value for US is IF.
Figure 6-1 shows the numeric keypad.
1.

Press I Com pose Character82 Typing Additional Characters•

OJ on the numeric keypad.

2.

Press

3.

Press [J on the numeric keypad.

You can use a hexadecimal compose sequence to send the DCS (device
control string) character. The hexadecimal value for DCS is 90.
Figure 6-1 shows the numeric keypad.

1. Press I Com pose Character I.
2.

Press [I] on the numeric keypad.

3.

Press [2J on the numeric keypad.

NOTE

If the terminal mode feature in the General Set-Up screen is
set to VT400 Mode, 7 Bit Controls, the 7-bit representation of
DeS (ESe P) will be sent.
Invalid Hexadecimal Sequences

0

Pressing the IEnterl key, the(period) key, or any key other than the
numeric keypad keys cancels the sequence and sounds the warning bell.
You can tum the warning bell on or off in the Keyboard Set-Up screen(Chapter 5).

EJEJEJEJ[][][]EJ[]~[]D[]~~D

1°

Key Name

Hexadecimal Digit

PF1

A

PF2

B

PF3

C

PF4

D

Minus

E

Comma

F

I~·
GSF _0643_S9,DG

Figure 6-1

Hexadecimal Compose Keys

Typing Additional Characters 83

Table 6-1

Key Sequences

Character

Sequence

Character

Sequence

quotation mark.. (sp)s u perscri pt 2

2/\number sign++

superscript 33/\

apostrophe' (sp)

1J.

micro sign/Ucommercial atAAenparagra ph signP!

opening bracket( (middle dot

backslash/ / or / <superscript 1

1/\closing bracket

) )

0-

circumflex
accent/\ (sp)masculine
ordinal»' (sp)

closed angle
brackets»grave accent
opening brace

( -

lA

fraction onequarter

14

vertical line

//\

Yz

fraction one-half12closing brace)-i,inverted?

??

tilde

- (sp)

'A

!!

A
A

A graveinverted!

A acutefA¢cent sign

C / or C I

AA circumflex/\A£

pound sign

L- or L=yA

A tilde-A

yen sign

Y- or Y=A

A umlaut··A§

section sign

SO or S! orSO

A

A ring°A or A*ccurrency sign

XO orXO©

copyright sign

CO or COfeminine ordinalA_

open angle
brackets«degree sign0/\plus or minus
sign

+-

#

@

\

/\

«

±

/\

(degreesign)lE

A E diphthong

AE

9
E
E
E
E

C cedillaC,

E grave'E

E acute'E

E circumflex/\E

E umlaut··E orE"

84

Typing Additional Characters

CharacterN
6

Sequence

CharacterI grave'Irea e diphthongae

I acuteIIfc cedillac, (comma)

I circumflexAI

e gravee

I umlaut·1 or "Ie acute'e

N tilde-Neeee circumflex

Sequence

Ae

..

0

o graveo acuteo circumflex
o tildeo umlauto E diphthong"o slashiJ

V graveU

V acute'V0o circumflex

V circumflex

AV0o tilde

-0

6
6
6
6
<E

(J

'0

e

e umlaute or "e'0i grave'iAO

i acute-0i circumflex'i
A·1··0 or "0

i umlaut··i or "iOEfin tilde-n0/0o grave0'V

6o acute' 0

AO

V umlaut··Vor "V0o umlaut..o or "0

Y umlaut*·Yor "Yreo e diphthong*oe

13German small
sharp sss

0o slash

0/

U

a
a
a

u graveua graveaUu acute'ua acute'aUu circumflex

AUa circumflex

Aaii

u umlaut.. u or "uaa tildeyy umlaut'Uyaa umlautaa ring-a..

a or "a°a or a*(degreesign)..

yor "yTyping Additional Characters

Character

Sequence

85

Character

Sequencey

Yacute,yyyacute'yI>

capital Icelandic
thorn

TH

p

small Icelandic
thorn

th

D

capital Icelandic
Eth

-D

0

small Icelandic
Eth-d

ISO Characterst

no break space

sp sp

broken verticalbar

I I or ! 1\

logical not

soft (syllable)
hyphen®

registeredtrademarkmacron%three quarters~

division signX

multiplication
sign

RO
1\

34

xx

acute accentcedilladiaeresis.. (sp) or " "*This character is only available when
you use the DEC Multinational Character
Set. See the UPSS feature in the General
Set-Up screen (Chapter 5).
tThese characters are only available when
you use the ISO Latin Alphabet No. 1
character set. See the VPSS feature in the
General Set-Up screen (Chapter 5).

This chapter describes how to:• Run two computer sessions on your terminal at the same time.
• Select and use windows.
• Copy and paste text between sessions.
With two sessions, your VT420 becomes two terminals in one. You canalso use the VT420 as a conventional one-session terminal.
Running two sessions offers many advantages. For example, you caneasily display and compare data from two different jobs at the sametime. To display data from two sessions, you divide the screen into two
windows. You can also copy and paste text from one session to another.

What Are Sessions?
A video terminal lets you exchange information with a computer system.
In order to communicate with the host system, you must open a session
from your terminal. A session is an active connection between theterminal and a host system. On many systems, you open a session bylogging in to the system.

86

Using Two Sessions, Windows, and the Copy and Paste Feature

87

Two Sessions
The VT420 lets you run two sessions at the same time. Opening two
sessions is easy. Mter you set up the VT420 for two sessions, you can
use the ~ (Session) key to move back and forth between two sessions.
The session you are using is called the active session. The next section
describes how to open two sessions.
You can connect the VT420 to a host computer, a terminal server, or amodem. This means you can run two sessions on the same host system oron two different systems.

Opening Two Sessions
The VT420 uses a communication cable to exchange information with acomputer. You ~an use one or two communication cables for two sessions.
To use one cable, your system must have Digital's Session Support Utility
software or a terminal server that supports multiple sessions.
Chapters 2 and 3 describe how to install communication cables and set
up the terminal for two sessions. This section describes how to use twosessions after you set up the terminal correctly.
The way you open two sessions depends on how many communication
cables you use. The following sections describe how to open two sessions
if you use• Two cables• One cable and SSU software• One cable and a terminal server that supports multiple sessions. If You Use Two Cables
This section describes how to open two sessions if you use two
communication cables.
IMPORTANT

Make sure your Vf420 is set up correctly before you try to open
two sessions. Chapter 3 describes how to set up the terminal fortwo sessions using two cables.

88

Using Two Sessions, Windows, and the Copy and Paste Feature

Session 1

You open session 1 the way you normally do on your host system. The
VT420 always connects you to the system assigned to session 1. This
assignment is based on the cable connections at the rear of the terminal.
To assign a system to a session, you use the terminal comm. ports
feature in the Global Set-Up screen.
Session 2!BI

Mter you open session 1, you press the(Session) key and open session
2 the same way you opened session 1. When you press ~ (Session), theVT420 maintains session 1. The session can still receive information fromthe host system. No information is lost.
If the terminal does not respond correctly when you press ~ (Session),
repeat the set-up procedure for two sessions in Chapter 3.

ExampleThe following example shows you how to open (log in to) two sessions on
one of Digital's VAXNMS systems:
NOTE

The Guide to Using VMS provides detailed information on how to
log in to the VMS operating system.
To open session 1:
1. Turn on the VT420 and wait for the screen to display VT420 OK.

I

2. Press the , Return key to tell the system you want to log in.

3. The systej proiPts you for your user name. Enter your user nameand press Return.
4. The s stem rompts you for your password. Enter your password andpress Return.
The system does not display your password. When you correctly type yourname and password, the system displays a VAXNMS version number anda $ (dollar sign) prompt. The $ indicates you have logged into session 1
successfully.

Using Two Sessions, Windows, and the Copy and Paste Feature

89

The login sequence looks like this:IReturn I
Username: Sm;ith
Password:

IReturn I(not displayed)

IReturn I

To open session 2: Press the ~ (Session) key and repeat the login
sequence.

If You Use One Cable
If your system has Digital's SSU software or a Digital terminal serverthat supports multiple sessions, you can run two sessions over one
communication cable. Your system manager can tell you if your system
has either one.
If Your System has SSU Software

If your system has Digital's SSU software, use the following procedure to
run two sessions oyer one communication cable:
IMPORTANT

Make sure your VT420 is set up correctly before you try to open
two sessions. Chapter 3 describes how to set up the terminal fortwo sessions, using one cable and SSU software.
Session 1

To open SSU session 1:
1. Log into your host system the way you normally do.
2. Enable SSU with two sessions on your terminal line.
On a VAXlVMS system, enter the following command at the $ prompt:$ SSO ENABLE

IReturn I

The terminal should display the following response on the status line
at the bottom of the screen:
Done

90

Using Two Sessions, Windows, and the Copy and Paste Feature

The first session is now open.
NOTE

If you type information before the Done message appears on thestatus line, the terminal displays the Service name = prompt.
Session 2

To open a second session:
1. Press the ~ (Session) key.
NOTE

If you did not enable SSU in step 2 above, the host system will
not respond when the terminal tries to open the second session.
After 10 seconds, the warning bell rings twice and a message
appears on the status line, indicating that the host did nQt
respond.
2. The system prompts you for the service name.
Service name=

VAXlVMS systems ignore the service name. Go to the next step.
3. Press IReturn I. The system responds with
Session Open Request Pending

immediately followed by
Session Opened

Session 2 is now open. On a VAXlVMS system, you should see a login
prompt on the screen. On other systems, the system is ready for thelogin procedure.
4. Type your login procedure before the terminal sends a timeout message.
If you get a timeout message, go to the previous step and repeat theprocedure.

Using Two Sessions, Windows, and the Copy and Paste Feature

91

If Your Terminal Server Supports Multiple Sessions

The DECserver 200 and DECserver 300 terminal servers support multiple
sessions. If your system has one of these terminal servers, you can use
the following procedures to run two sessions over one communication
cable. First, you must define you terminal server port for multiple-sessionuse.
Defining Your Terminal Port for Multiple Sessions

1. Turn on the VT420 and wait for the screen to display VT420 OK.

I

I

2. Press the Return key twice and log in to your terminal server the way

you normally do. The Local> prompt appears.
3. At the Local> prompt, enter the following command:
Local> DEFINE PORT MULTISESSIONS ENABLED

IReturn !

The terminal displays the following response on the status line at thebottom of the screen:Done

The terminal server port is now defined for multiple sessions. Thissetting remains in effect after you log out. You do not have to repeat thiscommand each time you log in to the terminal server.
Now, you can open two sessions.
Session 1 from the Terminal Server

To open session 1:
1. Press the ~ (Session) key. The terminal server prompts you for theservice name at the bottom of the screen.

2. At the service name prompt, enter the node name. Your systemmanager can tell you the node name.
Service name = {Node name}!Return!

The following response appears on the status line at the bottom of thescreen:Session Opened

92

Using Two Sessions, Windows, and the Copy and Paste Feature

Session 1 is now open on the terminal server. Now, you should log in to
your system.
3. Type your login procedure before the terminal server sends a timeout
message. If you get a timeout message from the terminal server, go to
the previous step and repeat the procedure.
Session 2 from the Terminal Server

To open session 2, repeat the three steps used to open session 1.
Disabling Multiple Sessions from the Terminal Server

1. Log out from one session the way you normally do.

The terminal displays a response indicating that you logged out.
Then the terminal server displays a response that indicates which
session (lor 2) you closed:
Local -nnn- Session n disconnected from (Node name»Local -nnn- 1 other session(s) active

2. Press the ~ (Session) key.
3. Repeat step 1 for the second session.
4. At the Local> prompt, enter the following command:
Local> DEFINE PORT MOLTISESSIONS DISABLED

IReturn I

The terminal displays the following response on the status line at thebottom of the screen:
Done

The following response appears after the logout response:
Local -XXX- Session Management terminatedMultiple sessions are now disabled from your terminal's port on theterminal server.

Using Two Sessions, Windows, and the Copy and Paste Feature

93

Restoring an Interrupted SSU Session
You can restore sessions that are interrupted by one of the following
events:• Turning the terminal off when it is still connected to the terminal
server• A power failure or similar problem
When a session is interrupted, the VT420 or the host system may lose
the context of the current session. Mter the terminal and system regain
communication, you can restore the context of the interrupted session
without canceling the session and starting over again.

To restore a session: Press theB (Session) key.

SSU Screen and Error Messages
The VT420 displays SSU screen and error messages on the line at thebottom of your screen. The messages disappear when you press any
keyboard key.
The following paragraphs describe each SSU message. If the message isan error message, the keyboard's warning bell rings twice befflre the themessage appears.
•

Sessions not enabled - Unable to run with host Session Management
version

The terminal's version of SSU firmware does not match the system's
version. Check with your system manager.
•

Sessions not enabled - No Session Management response from host

The system's SSU software is not working or is not installed. Also,
you may have lost your connection with the system. Check with yoursystem manager.
•

Sessions enabled - Restoring previous sessions

The host system is servicing an SSU request. Wait briefly for themessage to disappear.

94•

Using Two Sessions, Windows, and the Copy and Paste Feature

Session open request pending

The host system is servicing an SSU request. Wait briefly for themessage to disappear. If the message is followed by No response fromthe host for SSU Session Management, check your connection to thehost. If your terminal has been disconnected from the host, you must
log in and start your SSU sessions over again.
•

Insufficient host resources to open session

There is an error at the host system's end of the SSU session. Contact
your system manager for help.
•

Data overrun occurred on Session (lor 2)

A communication error has occurred between the terminal and the hostsystem. If this message disappears and does not reappear, the hosthas corrected the error on its own. If the message continues to appear,
contact your system manager for help.
•

Session (number) terminated abnormally

The host system has ended the session. Try opening the session again.
If you cannot reopen the session, there is a problem with the hostsystem. Check with your system manager.

Which Session is Active?
You can display information from two sessions at the same time, by using
windows. However, you can only enter information in one session at atime. There are two ways you can tell which session is active.
• Look at the keyboard indicator line. The active session number appears
in the first field at the left of the line.
• Look at the cursors. The active session usually has a blinking cursor.
The inactive session has a steady cursor.
NOTE

The cursor blink feature in the Display Set-Up screen lets you
select a blinking or steady cursor for the current session.
• Type a keyboard character. The software application will display thecharacter in the active session.

Using Two Sessions, Windows, and the Copy and Paste Feature 95

Number of Lines/Screen
You can display 24, 25, 36, or 48 lines of information at one time on
the screen. By default, 24 lines are visible at one time (excluding thestatus line at the bottom of the screen). If you display 36 or 48 lines on
the screen, the size of the characters will be smaller. The lines/screenfeature in the Display Set-Up screen controls how many lines you can see
on the screen at one time.
The nwnber of lines on the screen also depends on the number of lines ona page in page memory. For example, if you select 48 lines/screen but thepage size is 24 lines, then you will only see 24 lines of information fromthat session. This is the case even if there is room for more lines on thescreen. If you are running two sessions, you can select 48 lines/screen todisplay 24 lines in each session.

How to Change the Number of Lines/Screen
The number of lines on the screen is a user preference feature. You
may have terminal management software that automatically selects
the appropriate number of lines on the screen. However, if you want tochange the setting manually, use the following procedure:
NOTE

If you are running two sessions and you want to change thenumber of lines/screen setting for each session, you must makethe change for each session individually.
The Display Set-Up screen contains the lines/screen feature.
1. Press ~ (Set-Up). The terminal displays the Set-Up Directory.
2. Use the arrow key to move to the Display Set-Up field.
3. Press IEnter I. The terminal displays the Display Set-Up screen.
4. Use the arrow keys to move to the 24 Lines/Screen field.
5. Press IEnter I to change the setting to 36 or 48 lines/screen.
6. Press ~ (Set-Up) to leave set-up.

96

Using Two Sessions, Windows, and the Copy and Paste Feature

Windows
A window is an area of the screen that displays information from one
session. You can divide the VT420 screen into two windows by opening
two sessions.
The amount of information you can display is determined by:• The number of win~ows you are using (lor 2)• The page size you are using. Pages in page memory may be larger than
the number of lines available on the screen.
• The number of lines/screen you choose in the Display Set-Up screen.

One Window
Normally, the VT420 uses a full-screen window. In this window, you
can only display one session at a time. A full-screen window lets you
display 24, 25, 36, or 48 lines of text in 80 or 132 columns. If you use twosessions, you can switch between sessions with the ~ (Session) key.

Session 1

Session 2

24/36/48 Display Lines

24/36/48 Display Lines

Press ~ (Session).

Using Two Sessions, Windows, and the Copy and Paste Feature 97

Two Windows
The VT420 lets you divide the screen into two windows. When you divide
the screen into windows, each window can display 12, 18, or 24 linesof text in 80 or 132 columns. The default is one-half the number of thelines/screen setting you selected.

Session 1
24 Display Lines
Session 2
24 Display Lines

48 Lines/Screen

How to Select One or Two Windows
Before you use two windows, make sure the term.inal comm ports
feature in the Global Set-Up screen is set correctly. See Global Set-Up
screen in Chapter 5.
To select a new window style, press ICtr11 ~ (Session). Each time you press
ICtrl/ ~ (Session), the style of window on the screen changes.
Pressing ICtr11 ~ (Session)

Gives You .•.

One time'IWo windows

Again

A full-screen window again

IMPORTANT

Before you use windows, read the next section on keeping the thecursor visible.

98

Using Two Sessions, Windows, and the Copy and Paste Feature

To select two windows:rr
Session 1
Session 1
Session 2\.

Press ICtrli ~ (Session) once ....

To select one full-screen window again:

Press ICtrl! ~ (Session) again.

Keeping the Cursor Visible
When you divide the screen into windows, half of the area for the active
session may disappear. If the cursor for the active session is in the areathat disappears, the cursor may also disappear.
For example, if the screen has 24 lines and you divide the screen
horizontally, the top window displays only the top 12 lines of that session.
If the cursor is between lines 13 and 24, you cannot see the cursor.

To make sure the cursor stays visible, you can use the coupling featuresin the Display Set-Up screen (Chapter 5).
If you use one or two
windows

Make sure the vertical coupling feature is set
to Vertical Coupling.

Using Two Sessions, Windows, and the Copy and Paste Feature 99

If your application uses
multiple pages and you movefrom page to page in page
memoryMake sure the page coupling feature is set toPage Coupling.

How to Change Window Sizes
When you use two windows, you can change the relative size of thewindows. The VT420 displays a border between the two windows. You
can move the border up or down:rr
Session 1

Session 1

Session 2

Session 2

Press IShiftllCtrl! ~ to move the border up(or IShiftllCtrl! ill to move the border down).
To move theborder •..

Press ...

Up

IShiftllCtrl!

Down

OJ
IShift IICtrl\ OJ

Tips on Using Windows
If the vertical coupling feature is enabled, data on the screen may

appear to skip up and down when you move the cursor beyond the top
and bottom border of a window. The skipping occurs because the VT420
must update the screen to keep the cursor visible.
This problem occurs most often with applications that involve frequentcursor 'action (for example, word processors). Here are a few suggested
solutions.
• Disable the vertical coupling feature in the Display Set-Up screen.
This step will stop the skipping motion on the screen. However, thecursor will disappear if it moves to an area of the terminal's memorythat is not on the screen.

100

Using Two Sessions, Windows, and the Copy and Paste Feature

For example, if you split the screen so that each session displays 12lines of text, the cursor will disappear if it moves to line 13 in either
session.
• Set the application to use only the number of lines actually displayed.
When you split the screen horizontally, the terminal displays 121ines
in each session by default. Many applications have commands to limit
the number of lines available for editing. Here are two examples.
-Digital's EDT editor has a SET LINES command that lets you specify
the number of lines available for editing. If you set the number oflines to match the lines/screen feature in the Display Set-Up screen
when you use two windows, the skipping motion on the screen stops.
- Digital's VM:S operating system has a SET TERMINALlPAGE=nn
command. This command lets you specify the number of lines usedon the screen. Several VMS utilities and applications use thisinformation to limit the number of lines used. If you set the PAGE
to one less than the number of displayed lines, applications such as
HELP, NOTES, MAIL and the TPU editor (EVE and EDT sections)perform well when you use two windows.

Panning
You can pan the window for the active session, to view more data in page
memory. Panning a window is similar to panning a camera. When you
pan a camera over a subject, you can see different parts of the subject
while standing in the same position. When you pan a window, you can see
another part of page memory without moving the window on the screen.

How to Pan
You can pan a window up or down. You can also pan to another page inpage memory. To pan a window, you use the following keystrokes:
To pan...

Press.•.

Up

ICtr11

Down

ICtrllOJ

Back one page

ICtrlj IPrev

Forward one page[I]

I
ICtr111 Next I

Using Two Sessions, Winaows, and the Copy and Paste Feature

101

The Difference B~tween Panning and Scrolling

Panning directions are the opposite of scrolling directions. For example,
when you pan up, data appears to scroll down on the screen. The
following figure shows the difference between scrolling and panning.
Scrolling
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA

BeforeBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB8BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBAAAAAAAAAA
AAAAAAAAAA

After Scrolling Up

BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB

cccccccccc
cccccccccc
cccccccccc

cccccccccc
cccccccccc
cccccccccc }0000000000
0000000000

0000000000
0000000000

Page
ScreenPanning

Data Scrolled
Past Top Margin
Is Lost fromPage Memory~
Data Added

Page
ScreenUser
Window

BeforeAfter Panning Down

AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAABBBBBBBBBB

ScreenAAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAABBBBBBBBBB::::::::::BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB

Page

*

AAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA~.B B B B B B B B B B
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BB8BBBBBBB

L..::::=======:::::::J~~~
ScreenAAAAAAAAAA
AAAAAAAAAA
AAAAAAAAAA
AA·AAAAAAAA;A;-;A;A~;;

AAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB

Data Is Not
Lost-fromPage Memory.
Because Data
Does Not
Move on Page::::::::::Page** Page Must Be Larger Than 24 Lines

Notes About Panning• You can only move to another page if memory is divided into more than
one page.
• In order to pan on a page, the page size must be larger than thewindow. The page arrangement feature in the Display Set-Up screen(Chapter 5) determines the page size.
• Your cursor may disappear from the screen when you use panning
functions. There are two ways you can bring the cursor back on thescreen.
Look at the status line. It shows you the cursor location. Then use
the ICtr11 and arrow keys to pan the cursor back onto the screen.

102

Using Two Sessions, Windows, and the Copy and Paste Feature- Make sure the two cursor-coupling features-vertical coupling andpage coupling-are enabled in the Display Set-Up screen.

Copying and Pasting Text
The VT420 provides a simple procedure for copying and pasting data
within an active session or between two active sessions. The VT420 storesthe copied data in a buffer before sending the data to the host. The paste
buffer can hold one 24-line page of text data.

Copying Text into the Paste Buffer
To copy text into the paste buffer:
1. Press and hold the ~ (Copy) key down for the rest of the copy
gg,eration. If the cursor was not visible, it appears when you press~ (Copy).

NOTE

Releasing ~ (Copy) before completing the copy operation
cancels the operation.
2. Use the arrow keys to position the cursor at the beginning of the text
you want to copy.

3. With the cursor at the beginning of the text you want to copy, press the. ISelect Ikey.

4. Use the arrow keys to position the cursor one character beyond theend of the text you want to copy. As you move the cursor, the terminal
underlines the text you are copying.
5. Press the IRemove Ikey, then release ~ (Copy).

Mter you complete the copy operation, the terminal places the copied text
in the paste buffer and erases the underline from the text on the screen.
state.

Using Two Sessions, Windows, and the Copy and Paste Feature

103

Pasti ng Text
Mter you copy text to the terminal's paste buffer, you can paste the text
into an active session. When you paste the text, it appears on the screen
as if it were typed from the keyboard. You can paste text into a file. To
paste text:
1. If you are editing a file, use the arrow keys to position the cursor where
you want to paste the text.
If you are at the command level, text will appear on the command line
when you paste it.

2. Press and hold the ~ (Copy) key down while you press thellnsert\ key.
3. Release ~ (Copy).
The terminal sends a copy of the text in the paste buffer to the active
session. The text also remains in the paste buffer until you:• Copy additional text, or• Turn the terminal off.
The following figure shows an example of copying and pasting text fromone active session to another:

Session1

AAAAAAAAAABBBBBBBBBBCCCCCCCCCC

Session1

DDDDDDDDDD

DDDDDDDDDDAAAAAAAAAADDDDDDDDDD

Session2

AAAAAAAAAABBBBBBBBBBCCCCCCCCCC

Session2

AAAAAAAAAABBBBBBBBBBCCCCCCCCCC

DDDDDDDDDD

104

Using Two Sessions, Windows, and the Copy and Paste Feature

Notes About Copying and Pasting Text
• You can copy up to 24 lines of 132 characters at one time.
• If you try to copy non-ASCII characters, such as graphics information,
the VT420 sends blank spaces in place of those characters.

• You cannot copy the visual character attributes of text, such as bolding,underlining, and blinking.
• If you release the ~ (Copy) key before completing the copy or paste
operation, the terminal cancels the operation.
• If you set the transmit baud rate to Transmit=19200 or higher in
the Communications Set-Up screen, a copy and paste operation may
send data to the host computer faster than the host can receive thedata. When you are using the VMS operating system, type the SETTERMIHOSTSYNC command to control data flow and prevent the lossof data.

You can connect a printer directly to your VT420. This chapter describes
the Printer Set-Up screen and the types of printers you can use. The
chapter also describes how to use a modem with the terminal.

Printers
The VT420 has a built-in serial printer interface that supports many
draft, letter-quality, and laser printers, as well as plotters. Here are someof the Digital printers and plotters you can use with your terminal:
LA. Series

Letter-Quality

Laser

Plotter

LA12

LA38

LQP02

LNOI

LJ250

LA34

LA50

LQP03

LN03

LJ251

LA35

LA75

LA36

LAI00lLA2I0

105

106

Printers and Modems

Connecting a PrinterThe VT420 uses the Comm2 port to connect a printer.
1. Connect a DEC-423 cable from the printer to the 6-pin Comm2
connector.

2. Make sure the installabon is correct. Check the appropriate cabling
section in Chapter 2.
One session (one cable) and a printerTwo sessions with SSU software (one cable) and a printerNOTE

You cannot connect a printer to the Comm2 port if the VT420 is
set up for two sessions using two cables.

Selecting a Print Mode
The VT420 lets you select from three different print modes, using theprint mode feature in the Printer Set-Up screen (Chapter 5):• Normal mode (default)• Auto print mode
• Controller mode
The status line (Chapter 4) displays the current print mode setting.

Normal Mode: Printing Pages of Text
This mode lets you print displayed text by using the ~ (Print) key. Page
refers to the current page in the terminal's page memory. This page may
be larger than the screen. The size of the page depends on two otherset-up features.
FeatureSet. Up Screen

FunctionPage
arrangement

Display Set-Up

Selects the page size. By default thepage size is 24 lines, which matches
the default screen size.

Printer extent

Printer Set-Up

Lets you print a page or the scrolling
region. The scrolling region is the area
within the scrolling margins.

Printers and Modems

107

Auto Print Mode: Printing Text from the Host System
In this mode, the VT420 sends the current display line to the printerwhen the cursor moves to the next line after a line feed, form feed,vertical tab, or autowrap. Auto print mode lets you print each line as it isreceived from the host.
While selected, Auto Print Mode appears on the status line. You can still
perform printing functions with the ~ (Print) key in auto print mode.
You can also turn auto print mode on and off by pressing ICtrlj ~ (Print).
When you leave auto print mode, you return to normal print mode.

Printer Controller Mode: Letting the Host Control Printing
In this mode, the host system can send text directly to the printer, without
displaying the text on the terminal's screen.
While selected, Printer:

Controller appears on the status line.

You cannot use the ~ (Print) key in printer controller mode.

Local Controller Mode: Setting Up the PrinterThis mode lets you send information directly from the keyboard to theprinter, without displaying the information on the screen. You may findthis feature useful in setting up certain printers for operation, without
involving the host system. To select local controller mode, you must set
two different set-up features (Chapter 5).
1. Set the on-linellocal feature in the Global Set-Up screen to Local.

2. Set the print mode feature in the Printer Set-Up screen to Controller
Mode.

108

Printers and Modems

Assigning a Printer in Two Sessions
The VT420 lets you assign a printer exclusively to one session or share
the printer with both sessions. To assign the printer, you use the printerassignment feature in the Global Set-Up screen. There are three possible
settings:
Printer shared (default)
Printer session 1
Printer session 2
NOTE

The printer assignment feature is not enabled if the printer port is
assigned as a normal communication port for one of the sessions(in the Global Set-Up screen).

Printer Set-Up Screen
This screen lets you select features to match those of your printer.
Table 8-1 describes the features on the Printer Set-Up screen.
Notes About Printing• If you enter set-up while printing, the VT420 temporarily suspends
print operations. When you leave set-up, the printer resumes print
operations.

• For two sessions: the VT420 can save only one version of printercommunication set-up features (printer to host comm, print speed,
flow control, character format, and stop bits), because bothsessions share one printer line.
• Make sure the printer assignment feature on the Global Set-Up
screen (Chapter 5) is set to Printer Shared or to the session number
you want to print from (lor 2).
NOTE

The Printer Se1;..Up screen only appears if the terminal commports feature on the Global Se1;..Up screen is set to Sessions on
Comml or Sl=Comml.

Printers and Modems

Printer Set-Up

VT420 AV1.0

To Next Set-U

To Directory

Normal Print Mode

XOFF

Print Full Page

109

Speed=4800

No Printer To Host

8 Bits, No Parity

Print National Only

1 002,003

1 Stop Bit
No Terminator

Printer: Read

Modem: DSR

Session 1

GSF _1176_89A. DG

Table 8-1

Printer Set-Up Features

Feature and Settings

Description

Transmit speed!
receive speed
Speed=4800

Selects the baud rate the VT420 uses to send data
to a printer. The baud rates range from 300 to
38,400 bits per second.

Printer to host commSelects whether or not the printer can send data to
the host system.

No Printer to Host

Data can only move from host to printer.

Printer to Host

Data can move from host to printer and fromprinter to host.

Print mode

Determines when and how printing takes place.

Normal Print Mode

Lets you start print functions from the keyboard.

Auto Print Mode

Prints the current line of text when the VT420
receives a line feed, form feed, or vertical tab fromthe host.

Controller Mode

Lets the host send data directly to the printerwithout displaying the data on the screen.

Default settings are in bold type.

110

Printers and Modems

Table 8-1 (Cont.)

Printer Set-Up Features

Feature and Settings

Description

XOFF
XOFF
NoXOFF

Selects whether or not to use XONIXOFF flow
control with the printer.

NOTE

XONIXOFF flow control operates independently between the terminal andprinter, and between the terminal and host.
Data bits/parity
8 Bits, No Parity

Selects a character format to match the printer's.
You can select 7 bits (no, even, odd, mark, or spaceparity) or 8 bits (no, even, or odd parity).

Stop bits
1 Stop Bit
2 Stop Bits

Selects the number of stop bits (one or two) used by
the printer port UART.

Print Extent
Print Full Page
Print Scroll Region

Selects how much of the screen to print when youpress the ~ (Print) key.

Printed data type

Lets you restrict the character sets used forprinting, so they match the capabilities of theattached printer.

Print National Only

Use with a printer that supports the ASCII set (in8-bit multinational mode) or the current nationalset (in 7 -bit national mode). Examples: LA34,
LA36, and LA120 printers.

National and Line
Drawing

Use with a printer that supports the VT100line drawing set and (1) the ASCII set (in 8-bit
multinational mode), or (2) the current national set(in 7-bit national mode). Example: LAIOO.

Print All Characters

Use with a printer that supports the multinational
and line drawing sets. Example: LA50.

Print Terminator
No Terminator
Terminator = FF
Default settings are in bold type.-

Selects whether or not the VT420 sends a form feed(FF) at the end of a print operation.

Printers and Modems

111

ModemsYou need a modem if you want to connect your VT420 to a computer
system through a telephone line. The modem converts the serial
characters sent between the terminal and computer into signals that
can travel over telephone lines.
The VT420 can operate with full-duplex, asynchronous modems that meetthe following national and international standards. The modem you use
with your VT420 must be compatible with the modem used by the hostsystem.
EIA 232-D
CCITTV.24
CCITTV.2B
CCITTV.10
ISO 2110.2

Connecting to a Modem
You can use Digital's DF124, DF212, DF224, and DF242 modems with theVT420. You can also use compatible modems and acoustic couplers, suchas the AT&T's 103, 113, and 212 types. See Appendix B for information
on ordering modems.
To connect one of these standard modems to the VT420:
1. Connect the modem cable to the 6-pin DEC-423 connector on the rearof the terminal, or use a cable and adapter.
2. Go to the Communication Set-Up screen (Chapter 5).
3. Set the modem control feature to the appropriate setting:
Modem Control

If you plan to use modem features that require
additional signals beyond data leads only. Examples:
call origination and dialing from the keyboard, automatic
tpeej select, and disconnect on loss of carrier or when
Shift ~ (Break) is pressed.

Data Leads Only

If you do not plan to use modem control features or yourmodem (or modem cable) is not configured for modem
control.

4. While in the Communications Set-Up screen, set the transmit speed
and receive speed features to match your modem's settings.

This chapter is a summary of the control functions and commands
described in the VT420 Programmer Reference Manual. Programmers
can use this chapter as a quick-reference tool.
NOTE

The application of the control functions and commands on theVT420 effects each session independently.
The chapter is divided into sections that correspond to the chapters of
the VT420 Programmer Reference Manual. For example, to find out moreabout

2 Character Encoding
you would go to Chapter 2 of the VT420 Programmer Reference Manual.
Section2
Character Encoding
3
Keyboard Codes
4
Emulating VT Terminals

5
6
7
8

112

U sing Character Sets
Page Memory
Setting Visual Character andLine Attributes
Editing

Section9
Rectangular Area Operations
10
Cursor Movement and Panning
11
Keyboard, Printing, and Display
Commands
12
VT420 Reports
13
Resetting and Testing the Terminal
14
Session Management

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VT420 Programming Summary

115

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r ..
.." .. '\
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,
.. /
'
"
!
". -, .. ".
.. .
" ill'
..j
co

2

"

c.

'I'

CO

A2

I

3
4

1110'

5

I

6

--1

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L

7
8
9

l

10

J

V

105'0'
1"81

oX>

1010'

r

A1

1

~

I

11

(

12

l.

13

)

14

GL OR

2 10

~

1

15

OlOA

,

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'" X
5

A

<=:>
~

)

.,
"

J

...

111118T
C:>,. 20. n

.c cc

a06

co

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/\
.,

CF

a

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p

U

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1118
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au

100

U

2U

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17

215

127 )27,.214''''''
73 201"201l

no J')O

112"2.,. 202::;.

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72

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a:n
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u.

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c.

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101:2 U2
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123 US

V

IQ

217

&iii

0"

131 U2E

10122.

0, . , UI
102 no.. I ImYl

121 :21,11

EA" ",15"

OC
100

,oDD

u.

v

u au

a

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2,\1:270'6aata10701"

tat." 1''.. .. ",171.. .. "e
101aa.

Ie

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I ...

lU IU

"72,,

~

a,'

U
IE
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IF

""

1723721222'0---•t

17:1 313'':: ~'w'
11.',.
nol211i2

1C

"C

tal

au

n.

70 FO
1ft
1:1t U.
11
FE

IF

When S.t i. Mappea Into OR

BitBel.1

Control Characters
CO .(7-Bit) Control Characters Recognized

Name
Null

Mnemonic
Column/Row Function

NUL
0/0

Enquiry

Bell

BS

Sends theanswerback message.
(Communications Set-Up)

BELSounds the bell tone if
the bell is enabled in the
Keyboard Set-Up.

BS
0/8

HorizontaltabMnemonic
Column/Row Function

HT
0/9

NUL has no function(ignored by the terminal).

ENQ
0/5

017

Name

Moves the cursor one
character position to thelett. If the cursor is at
the left margin, no action
occurs.

Line
feed

Vertical
tab
Form
feed

LF
0/10

VT

Moves the cursor to thenext tab stop. If there
are no more tab stops,
the cursor moves to theright margin. HT does notcause text to auto wrap.
Causes a line feed ora new line operation,
depending on the setting ofline feed/new line mode.
Treated as LF.

0/11

FF
0/12

Treated as LF.

116

VT420 Programming Summary~ame~arriage

Mnemonic
Column/Row Function
CR
0/13

Moves the cursor to theleft margin on the current
line.

;hift out
Locking,hift 0)SO (LS1)
0/14

Maps the G1 character set
into GL. You designate G1
by using a select character
set (SCS) sequence.

;hift inLocking,hift 0)51 (LSO)
0/15)evice:ontrol 1
XON)

DC1
1/1

Maps the GO character set
into GL. You designate GO
by using a select character
set (SCS) sequence.
Also known as XON.
If XON/XOFF flow
control is enabled in theCommunications Set-Up,
DC1 clears DC3 (XOFF).
This action causes theVT420 to continue sending
characters.

)evice:ontrol 3
XOFF)

DC3
1/3

eturn

Also known as XOFF.
If XON/XOFF flow
control is enabled in theCommunications SetUp, DC3 causes theVT420 to stop sending
characters. The terminal
cannot resume sending
characters until it receives
a DC1 control character.

)evice:ontrol 4DC4
1/4

Introduces an SSU session
management command.
The VT420 and host use
this control to separate
SSU commands from ANSI
text and control functions.

~ancelCAN
1/8

Immediately cancels
an escape sequence,
control sequence, or
device control string inprogress. The VT420
does not display any error
characters.

Name

Mnemonic
Column/Row Function

Substitute

SUB
1/10

Immediately cancels an
escape sequence, control
sequence, or device
control string in progress.
The VT420 displays areverse question mark foran error character.

EscapeESC
1/11

Introduces an escapesequence. ESC also
cancels any escapesequence, control
sequence, or device
control string in progress.

DeleteDEL
7/15

Ignored when received,
unless a 96-character
set is mapped into GL.
DEL is not used as a fillcharacter. Digital does notrecommend using DEL asa fill character. Use NUL
instead.

C1 (8-Bit) Control Characters RecognizedName

Mnemonic
ColumnlRow Function

Index

IND
8/4

Moves the cursor down
one line in the same
column. If the cursor isat the bottom margin, thepage scrolls up.

Next line

NEL
8/5

Moves the cursor to thefirst position on the next
line. If the cursor is at thebottom margin, the page
scrolls up.

Horizontal
tab setHTS
8/8

Sets a horizontal tab stopat the column where the'cursor is.

VT420 Programming SummaryName

Mnemonic
Column/Row Function

Reverse
index

RI
8/13

Moves the cursor up one
line in the same column.
If the cursor is at the top
margin, the page scrolls
down.

Singleshift 2SS2
8/14

Temporarily maps the G2
character set into GL, forthe next graphic character.
You designate the G2 set
by using a select character
set (SCS) sequence.

Singleshift 3SS3
8/15

Temporarily maps the G3
character set into GL, forthe next graphic character.
You designate the G3 set
by using a select character
set (SCS) sequence.
Introduces a device control
string. Used for loading
function keys or a soft
character set.

Devicecontrol
string

DCS
9/0

Start ofstring

SOS
9/8

Ignored.

DEC
privateidentification

DEClO
9110

Makes the terminal send
its device attributes
response to the host(same as an ANSI device
attributes (DA) sequence).
Programs should use
the ANSI DA sequence
instead.

NOTE
If the printer is in controller mode, the terminal
sends the sequence to the printer.
Control
CSI
Introduces a control
se9/11
sequence.
quenceintroducer
Stringterminator

ST
9/12

Ends a device control
string. You use ST in
combination with DeS.

Name

117

Mnemonic
Column/Row Function

OperatingsystemcommandOSC
9/13

Introduces an operating
system command."PrivacymessagePM
9/14

Introduces a privacy
message string ...

Application
programcommandAPC
9/15

Introduces an application
program command.""'The VT420 ignores all following characters until it
receives a SUB, ST, or any other C1 control character.

8-Bit Control Characters and Their 7-Bit
Equivalents

Name

8-Bit
Character

7·Bit
Sequence

Index

IND

ESC 0

Next line

NEL

ESC E

Horizontal tab set
Reverse index

HTS

ESC H

RI

ESC M

Single shift 2

SS2

ESC N

Single shift 3

SS3

ESC 0

Device control
stringDCS

ESC P

Start of string

SOS

DEC private
identification

DEClO

ESC X
ESCZ

Control sequence
introducer

CSI

ESC [

String terminator

ST
OSC

ESC]

Privacy message

PM

ESC A

Application
program

APC

ESC

Operating systemcommand

ESC \

18

VT420 Programming Summary

Jsing Macros'he VT420 lets you define and invoke macros to suit
he needs of your application. A macro is a string
f ANSI text and commands downloaded into theerminal. By invoking the macro, you can execute aroup of control functions with one operation.

lame

Mnemonic

Sequence)efinelacro

OECOMACDeS Pid; Pdt; Pen! z 0 ... 0ST

Pidmacro 10 number (~63).

Pdt

macros to delete first.

0delete all current macros.
delete all current macros.

Otherterminal ignores the macro.

Pen

encoding format for macro
text.

0

standard ASCII characters.
hex pairs for each ASCII
character.

Otherterminal ignores the macro.

0 .. 0control string data.

OECINVMeSI Pid* z

repeat sequence introducer.
woke
lacro

Pid

macro 10
number.

Display Controls Mode
Display Controls Font (Left Half)
5

2
Ib'

d . '-,

Display Controls Font (Right Half)
6

1t2

:~

~O+-__~~~++'~~H-__~~-4~~~~__~+--+~1 p I~~~m
~I B I~I R I~I b I~I r

210 0, olsTxl :/Dc 2 1H1 • I:~I 2
31 0• , 'IETxl: IDC3 P:1 # 1;:1 3 ~I c I~I s I~I c I~I s "."''"
'I'
41 0, • oIEOTI: IDc4 1HI $ IHI 4 .. D I'ifl T m'l d ...
..
I IN AK 1"1
5 I- , -, IE NO:~~ % I":: I 5 .
EI:il u ml e ... ...
6 ,. , , 'IAcKI: ISyNIHI & IHI 6 ..
.. F v I:Y 'eO: I v ,.
710 , , "SELl; IETslHI ' IHI 7 ." G !jl w I:Y 9h
H 72' X
8
81",0Issl';IC AN IHI (",. 9 ".."
'2'
91' •• 'I HT I!'I E~.dHI ) ..
!:'I Y ~~II
l:!1 Z ::1 j
z '"
101'"
'ILF I~I ~ IHI •
,
,..
,,..
':~I
'"
" K -I;~'01
111' • , ,t v T I "IE~'
S C I~~ 1 +
,.
L .c
<
1 21' ,
'1 F F I ~ I F S H~~'c"1 I.c'c'::1 m 1:::1 } '""6131' , • 'I C R I~q G s IH
.0.." M
14/' , , 01 So I~I RS IH,. > :i I N I:~ '"... ". ,,....,.
52

U

i

..
..

..
..

'I s I I:} Ius I;~

I "",F

.. 10

'"7.
H

...,
....

'"

.F

j.-- CO Cod •• ---1....1...- - - - GL Cod •• (ASCII Graphic)
Key
Characl.r

ETIIl' Oc'.'
ESC

27

Decimal

19

Hex

10.11

X

.
.

"2

20
50

151' , ,

W

50

72

..
..

0

10,.

'71

50

iJ

U

10

... ...
..
52

~o6q

OJ

.. I

~iel

..

o

10

8

Bit.

1101

_

'"

DTI:~:

,F

-,

_I

80

81
82

83

12

11

14

13

15

b'

'--

...
PI1:1
F.!/
.,1 .:!: PIn A I~n N PHI a Pi,:1 ii ...
...'"F.:.:! "u IWI 4 .,~,:I ~ I~JI 0 I:I,:I ~ 1:;,:1 ;,A I~::I -9 I~.:I ~ m:1 ~ ...

IWI \ PHI '\,PU1'b3to2to1lAo..

o

FI

~:~I

2

m:1 \ IWI { P.:p

3

2

G

't ','"ll ~ 10.

1:(

A I~n 6t:,:1 A I~:I 8
•• 1

11::

D31

, .12

...

"
'"
PE;jl
"
a I~:I ~ PF~:;'\ pm ~ P.!:I ¥ n:: f I~I A I~I 6 Iml ~ :::1 ; ...
:.:.:1 \ P.!,:I : 1::,:1 n I~}I .t I~:I 0 FI':I I;:,~I ;; ..,'"mq § PHI . It:':1 ~ l~fI x Po;,'1 ~\'""T WI IWI . P:.:I . It!,:1 E I~:~I fi1 P.~.:I Ii ...
F.!) I @ pm
It:.~1 E It!.q u P].!I ,; ~o~1 u ::~
\
,n
SSA

6

1e

".1 \

I .. ,

~3.11

98

5

2111

99

u

8

f4

1

..
."..,

t~1 9A I~:.:j ! I~.;':I ~ I~!':I ~ I~:!I
IF.!! ~ jt:!1 u ,'"~~:I c~ I~!:I «I~~!I »ll~JI E 1~!31 0 IF!I e I~~_:I'"~~I ST I~~I -, j:.~;I'14 I~~:I i I~!JI i.i I~:.:I i w':1 U
R, I~~:I \ I~:JI - 1~:I'f2 It::1 i W~I y It::1 i It:JJ y

v

TS

\

a

\

I~::I ® I~:I 3/. It:~1 1 I~:I f It:JI ~ It::1 p\IWI\IWI-I~ L ~1 7 I~I B I~ y Iill I Y\ I~~IPM~ C1 Cod.. ·1_

BII_

(ISO

L.II".1GSRU~;I::.nt.' Graphic)

10

11
12
13

14

."...
I

1115

I

~

I\)

o

"a

co

m
3

3

:5'
co
(J)

c

3
3

m

-<

(0

20

VT420 Programming Summary

Codes Sent by Numeric Keypad Keys

Numeric Keypad Mode Setting (DECNKM);odes Sent by Editing KeysANSI Mode"

Code Sent

~ey

VT400
Mode

:ind

CSI1 -

nsert Here~emove;elect)rev

VT100, VT52 Modes
The editing keys do notsend codes in these
two modes.

Key

Numeric

Application Numeric

0

0
1
2
3

SS3 P
SS3q
SS3 r
SS3 s

0

1
2

4

SS3 t

4

ESC? t3
41
23

Application
ESC? P
ESC ?q
ESC? r
ESC ?5

CSI2 CSI3 -

5

5

SS3 u

5

ESC? u6

6

6

CSI4 -

7
8

7
8

SS3v
SS3w

ESC ?v
ESC?w

SS3 x

7
8

9

9

SS3y

9

(minus)SS3m(comma)SS31
SS3n

CSI5 CSI6 -Jext

VT52 Mode"

ESC? mt
ESC? 1 t
ESC? n~odes Sent by Arrow Keys(period)
Cursor Key Mode Setting (DECCKM)

Enter

SS3 M

PF1

CR or
CR
LF:t:
SS3P

PF2

SS3Q

ESC? x
ESC ?y

CR or
CR
LF:t:
ESC
P

ESC? M

SS3Q

ESC
Q

ESCQ

ANSI Mode'"

VT52 Mode'"(eyCursor

Application

Cursor or
Application

iJ

CSIA

SS3A

ESC A

CSIB
CSIC

SS3 B
SS3C
SS3 D

ESCB

PF3

SS3 R

SS3 R

ESC
R

ESCR

ESCC
ESCD

PF4

SS3S

SS3S

ESC
S

ESCS

IJ
~

:=J

CSIO

'ANSI mode applies to VT400 and VT100 modes. VT52
Tlode is not compatible with ANSI standards.

SS3 P

ESCP

"ANSI mode applies to VT400 and VT100 modes. VT52
mode is not compatible with ANSI standards.
tYou cannot use these sequences on a VT52 terminal.
:t:Keypad numeric mode. IEnter 1sends the same codesas I Return I. You can use line teed/new line mode (LNM)
to change the code sent by 1Return I. When LNM is
reset, pressing I Return 1sends one control character(CR). When LNM is set, pressing I Return I sends twocontrol characters (CR, LF).

VT420 Programming Summary

Codes Sent by the Top-Row Function Keys

Code Sent

Legend

VT400
Key
Number mode

VT100,VT52 modes

Control
Character
Mnemonic

Code
Table
Position

STX

0102

ETX

0103

Key
PressedWith[£!ill (AllModes)

F1*

EaT

0104

Print

F2*

ENQ

0105

E

Set-UpSession

F3*
F4*

ASK
BEL

0106

F

0/07

G

Break

F5*

BS

0108

H

F6

F6

CSI1 7-

HT

0/09

F7

F7

CSI1 8-

LF

0/10

J

F8
F9

CSI1 9CSI 20-

VT

0/11

FF

F10

F10

CR

0/12
0/13

F11 (ESC)

F11

CSI21 CSI 23-

ESC

SO

0/14

F12 (8S)

F12CSI24 -

BS

SI

0/15

F13 (LF)
F14

F13
F14

CSI25 CSI26 -

LF

1/00

Help

F15

CSI28 -

DLE
DC1
DC2

K
L
M
N
0
P

1/02

Do

F16

CSI29 -

DC3

1/03

St

F17

CSI31 -

DC4

1/04

T

F18

F18

CSI32 -

F19
F20

CSI33 CSI34 -

NAK
SYN

1/05

F19
F20

1/06

U
V

Keys Used to Send 7-Blt Control Characters

Control
Character
Mnemonic

Code
Table
Position

NUL

0/00

SOH

0101

Key
PressedWith~(A"
Modes)

2 or space bar
A

Dedicated
Function
Key

ETB

1/07

W

CAN

1/08

EM

1/09

SUB

1/10

X
Y
Z
3 or [
4 or 1
5 or]
6 or7 or?
8

1/11

FS
GS

1/12
1/13

RS

1/14

US

1/15

DEL

7/15

F13 (LF)*

Return

Qt
R

F17

ESC

F12 (BS)*
Tab

F8
F9

* F1 through F5 are local function keys that do not sendcodes.

Dedicated
Function
Key

B
C
D

Hold

1/01

121

F11 (ESC)*

Delete"'7-bit control characters sent in VT100 or VT52 modes
only.
t7-bit control codes sent only when XON/XOFF support
is off.

122

VT420 Programming Summary

ielecting an Operating Level (DECSCL)

Selecting Graphic Character Sets
1. Designate the set as GO, G1, G2, or G3.

)equence

Level Selected
Level 1

Designating Character Sets (SCS Sequences):S161 " p

VT100 mode

:516 n" p:S16 n; 0 "p:516 n; 1 " P:516 n; 2 " P

VT400 mode, 8-bit controls

Level 4*
VT 400 mode, 8-bit controls

You designate a hard character set as GO through G3
by using a select character set (SeS) escape sequence.
You cannot designate a 96-character set as GO.

VT400 mode, 7-bit controls (D)Format:

VT400 mode, 8-bit controls

Level 4 includes levels 2 and 3. In these sequences, n:an be 2 or 3, or 4
D) = default

iending C1 Controls to the Host)equence

2. Map the designated set into the in-use table.

Mode Before

Mode After11, intermediate character
Designates the character set as GO, G 1, G2, or G3.

11 Character

Code

Set Selection

94-Character Sets
left parenthesis

218

GO (initial settingfor GL);-Bit Controls (S7C1 T):SC sp F

VT400 mode,
8-bit controls

VT400 mode, 7-bit
controls

VT400 mode,
7-bit controls

Same. Terminal
ignores sequence.

VT100 or VT52
mode,-Bit Controls (SBC1 T)

Same. Terminal
ignores sequence.

:5C sp G

VT 400 mode,
8-bit controls

Same. Terminal
ignores sequence.

VT400 mode,
7 -bit controls

VT400 mode, 8 bit
controls

VT100 or VT52
mode

Same. Terminal
ignores sequence.

right parenthesis

219

G1

asterisk2110

G2 (initial settingfor GR)

plus sign+
96-Character Sets*

2111

G3

hyphen2113

G1

period

2114

G2

slash

2115

G3

*You cannot designate a 96-character set into GO.

l z... I n F, intermediate and final characters
Selects one of the following standard character sets:

VT420 Programming Summary

12 •• .In F
Characters

Character Set

Code

94·Character Sets
ASCII (initial G1 andGO setting)
DEC Supplemental
Graphic (initial G2 andG3 setting)

B

4/2

%5

215,3/5

DEC Special Graphics03/0

DEC TechnicalUser-preferredsupplemental

>
<

3/14
3/12

A

4/1

Locking shift
G3

LS3

ESC 0

G3 into GL.

Locking shift
G3 right

LS3R

ESC I

G3 into GR.

Single Shifts (SS)You use a single shift when you want to display thenext character from a different character set. A single
shift maps the G2 or G3 set into GL. The character
set is active for only one character. Then the terminal
returns to the previous character set in GL.

96·Character Sets
ISO Latin-1
Supplemental

Mapping Character Sets
After you designate a character set as GO, G 1, G2,
or G3, you must map the set into the in-use tableas GL or GR. To map a set, you use locking-shift or
single-shift control functions.

8-Bit
Code

7-Bit
Code

Function

Singleshift 2

SS2

ESC
N

Maps G2 into GL for
the next character.

Singleshift 3SS3ESC

Maps G3 into GL for
the next character.

Name

0

Assigning User-Preferred Supplemental Sets
(DECAUPSS)

Locking Shifts (LS)Default: DEC Supplemental Graphic

When you use a locking shift, the character set
remains in GL or GR until you use another locking
shift.

Sequence

Set Selected

DCS O! u % 5 ST

DEC Supplemental Graphic

DCS 1 ! u A ST

ISO Latin-1 supplemental

Name

Mnemonic Code

Maps •..

Locking shift
GO

LSO

SI

GO into GL.
(default)

ANSI Conformance Levels

Locking shift
G1

LS1

SO

G1 into GL.

ESC sp Final

The following locking shift functions are available only in
VT400 mode.
LS1R
G1 into GR.
Locking shift
ESC G1 right
LS2
ESCn
G2 into GL.
Locking shift
G2
Locking shift
G2 right

LS2R

ESC}

G2 into GR.

123

Final

ANSI Conformance Level

L

Level 1

M

Level 2
Level 3

N

Soft Character Sets
You can only load soft character sets in VT400 mode.

24

VT420 Programming Summary

haracter Cell Sizes
ell Size

80 Columns

132 Columns

10 pixels
16

6 pixels
16

10
10

6
10

10
8

6
8

Binary
Value

Hex
Value

Hex
Value +
3F Offset

001111010000010001
010010010011

F
10
11
12
13

4E
4F
50
51
52

010100010101010110010111011000

14
15
16
17
18

53
54
55
56
57

011001011010011011011100011101

19
1A
1B
1C
10

58
59
5A
5B
5C

011110011111
100000100001100010

1E
iF
20
21
22

50
5E
5F
60
61

100011100100100101
100110100111

23
24
25
26
27

62
63

b

64

d

65
66

e

101000101001101010101011101100

28
29
2A
28
2C

67
68
69
6A
6B

g

Character
Equivalent~ lines/screen

'idth
eight

; lines/screen
'idth
eight
~ lines/screen

idth
eight

onverting Binary Code to an ASCII Character

nary
Ilue

Hex
Value

Hex
Value +
3F Offset

10000
10001
10010
10011
10100

00
01
02
03
04

3F
40
41
42
43

10101
10110
10111
11000
11001

05
06
07
08
09

44
45
46
47
48

11010
11011
11100
11101
11110

A
8
C
D
E

49
4A
4B
4C
40

Character
Equivalent

?
@

A
B
C
0
E
F
G

H

I

J
K
L

M

N

0
P
Q

R
S

T
U

V

W
X
Y
Z
[

A

a

c

h

j
k

VT420 Programming Summary

Binary
Value

Hex
Value

Hex
Value +
3F Offset

125

DECDLD Parameter Characters
Character
Equivalent

101101

20

6C

1011102E

60m

1011112F

6E

n11000030

6F

0110001

31

70

P11001032

71q11001133

72100100347311010135

7411011036

75

u11011137

76v

11100038

77w

111001

39

78

x

1110103A

79

Y111011

38

7A

z1111003C

78111101111110

30
3E

7C
70

111111

3F

7E

Parameter Name

Description

Pfn

Font
number

Selects the ORCS font buffer to. load. Each session has only one
font buffer. Pfn has two valid
values, 0 and 1. Both values
refer to ORCS buffer 1 for eachsession.

Pcn

Starting
character

Selects where to load the firstcharacter in the ORCS fontbuffer. The location corresponds
to a location in the ASCII codetable. For example, a Pcn valueof 0 means that the first soft
character is loaded into position
210 of the character table. A Pcn
value of 1 means position 211 in
the table, and so on up to Pcn =95 (position 7/15).

s

Pcn is affected by the characterset size. See Pcss below.
Pe

Erase
control

Selects which characters toerase from the ORCS buffer
before loading the new font.
0erase all charactersin the ORCS buffer
with this number,width and rendition.
erase only
characters inlocations being
reloaded.

Downloading Soft Characters
Use the following sequence format:
2

DeS Pfn ; Pen; Pe; Pemw; Pss; Pt; Pemh; Pess { Dses
Sxbpl ; $xbp2 ;... ; Sxbpn ST

erase all renditionsof the soft character
set (normal, bold,
80-column, 132column).

NOTE
Erased characters are undefined (not blank). The
terminal displays these characters as the error
character (reverse question mark).

26

VT420 Programming Summary·arameter Name
'cmw

Charactermatrixwidth

Description

Parameter Name

Description

Selects the maximum character
cell width.

PssDefines the screen width andscreen height for this font.

Font
set
size

VT400 mode

0,1o

80 columns, 24lines. (default)

2

132 columns, 24
lines

11

80 columns, 36
lines

12

132 columns, 36
lines

21

80 columns, 48
lines

22

132 columns, 48
lines

10 pixels wide
for 80 columns, 6
pixels wide for 132
columns. (default)

1

illegal.

2

5 x 10 pixel
cell (VT220
compatible).

3

6 x 10 pixel
cell (VT220
compatible).

4

7 x 10 pixel
cell (VT220
compatible).

5

5 pixels wide.

6

6 pixels wide.

10

10 pixels wide.

If the number of columns or lines
per screen changes, the terminal
uses the appropriate variationof the soft set. If you try todisplay a ORCS character when
there is no soft set defined forthe current number of lines andcolumns, the terminal displays
the error character (reverse
question mark).
Pt

Text orfull cell

Defines the font as a text font or
full-cell font.

otext. (default)
text.

2

full cell.

FUll-ceil fonts can individually
address all pixels in a cell.
Text fonts cannot individually
address all pixels. If you
specify a text cell, the terminal
automatically performs spacing
and centering of the characters.

VT420 Programming Summary

Parameter Name

Description

Pcmh

Charactermatrix

Selects the maximum character
cell height.

height0 or omitted(default)=16 pixels high.

1 pixel high.
2

2 pixels high.

3

3 pixels high.

16

16 pixels high.

Pcmh values over 16 are illegal.
If the value of Pcmw is 2, 3, or
4, Pcmh is ignored.
Pcss

Dscs
defines the name for the soft character set. You use
this name in the select character set (SCS) escapesequence. You use the following format for the Dscs
name:

IF
I

is 0, 1 or 2 intermediate characters from therange 210 to 2115 in the ASCII character set.

F

is a final character in the range 3/0 to 7/14.

Sxbpl ; Sxbp2 ; ... ; Sxbpn
are the sixel bit patterns for individual characters,
separated by semicolons (3/11). Your character set canhave 1 to 94 patterns or 1 to 96 patterns, dependingon the setting of the character set size parameter(Pcss). Each sixel bit pattern is in the following
format:CharactersetDefines the character set as a
94- or 96-character graphic set.

s ...S/S...s

size

0

the first S ••. S
represents the upper columns of the soft character.

94-character set.
(default)
96-character set.

/ (215)

advances the sixel pattern to the lower columns of
the soft character.

The value of Pcss changes themeaning of the Pcn (starting
character) parameter above.

the second S •.• S
represents the sixels in the lower columns of thesoft character.

Examples•If Pcss=0 (94-character set)

The terminal ignores any attempt to load
characters into the 210 or 7/15 table
positions.
Pcn

ST
is the string terminator. ST is an 8-bit C1 character.
You can use the equivalent 7-bit sequence ESC \(1111, 5/12) when coding for a 7-bit environment.

Specifies
column 21row 1

Valid DECDLD Parameter Combinations
94

•

127

If PcssPcn
0column 7/row 14=1 (96-character set)Specifies
column 21row 0

Pt

o or 1
2

95

column 7/row 15

Pcmw

Pcmh

Pss*

o to 16o to 16o or 1

BO-Column, 24 Jineso to 8o to 10

0, 1

128

~

VT420 Programming Summary

Pcmw

Pcmh

Pss*

o to 162

1 to 162132-column, 24 lines) or 1o to 5o to 6r;JO-column, 36 lines) or 1o to 8o to 10o to 10o to 10

11
11

Setting the Page Format

Name

Mnemonic SequenceSetcolumnsper
page

DECSCPP CSI Pn $ I
Pn columns (80 or 132).

Columnmode

DECCOLM Set: CSI ? 3 h
132 columns.

132-column, 36 lines) or 1o to 5o to 6o to 10o to 10 .

12
12Reset: CSt ? 3 I
80 columns. (D)90-column, 48 lines) or 1o to 8o to 10o to 8o to 821
21132-column, 48 lines) or 1o to 5o to 6o to 8o to 8Set lines
per
page

22

DECSLPPCSIPntPn lines per page.
The number of pages dependon how many sessions you
use.

22

'The default values are the maximum legal values in~ach case.

Dual
Sessions

SingleSession

24

3
pages

6 pages

Pn~Iearing a Soft Character Set

25

2

5

{ou can clear a soft character set that you loaded into
;he terminal by using the following DECDLD control;tring:36

2

4[)CS 1;1;2 { 8P @ ST

144

48

3

72

2

\ny of the following actions also clear the soft
:haracter set:tttPerforming the power-up self-test.
Selecting Recall or Default in the Set-Up
Directory.
Using a reset to initial state (RIS) sequen:ce.

Set leftandrightmargins

DECSLRM CSI PI; Prs
PI = left column.
Pr = right column.

VT420 Programming SummaryName

Mnemonic Sequence

Set topandbottommargins

DECSTBM CSI Pt; Pb r
Pt = top line.
Pb = bottom line.

Originmode

DECOM

DECVSSM

Character and Line Attribute SequencesName

Mnemonic

Sequence

Select graphic
rendition

SGR

CSI PS ... Ps m
Ps = character
attribute value(s).
(See the list below.)

Left and right margins can bechanged.

Single-width,
single-heightline

DECSWL

ESC #5

Reset: CSI ? 6 9 I
L~ft and right margins cannot
be changed. (D)Double-width,
single-heightline

DECDWL

ESC #6

Double-width,
double-heightline

DECDHL

ESC # 3 (top half)
ESC # 4 (bottom half)

Set: CSI ? 6 hMove within margins.
Reset: CSI ? 6 I
Move outside margins. (D)Verticalsplitscreenmode

S~: C~?69h(D) = default.

Moving Through Page Memory
Visual Character Attribute Values
Name
Next
page

Mnemonic Sequence *NP

CSI Pn U
Move Pn pages forward.
C = home.

Precedingpage

PP

CSI PnV
Move Pn pages backward.
C = home.

Page
position
absolute

PPA

CSI Pnsp P
Move to page Pn.
C = same as old page.

Page
positionbackward

PPB

Page
position
relative

PPR"C= new cursor position.

129

CSI Pnsp R
Move Pn pages backward.
C = same as old page.
CSI Pnsp Q
Move Pn pages forward.
C = same as old page.

Ps

Attribute

VT100 or VT400 ModeoAll attributes off

4
5

Underline
Blinking

7

Reverse video

Bold

VT400 Mode Only
22

Bold off

24

Underline off
Blinking off
Reverse video off

25
27

130

VT420 Programming Summary:diting Sequences~ame

Mnemonic

Sequence

nsertlreplace
node

IRM

Set: CSI4 hInsert characters.

)elete:olumn

DECDC

nsert
:olumn)elete line

DECIC
DL

Reset: CSI 4 I
Replace characters.
CSIPn'Pn columns.
CSI PnPn columns.
JIL

CSI PnDCH

nsert:haracter

ICH

CSI Pn P
Pn characters.
CSI Pn@Pn characters.

Ps:rase inine

0, cursor to end. (D)
1 , beginning to cursor.

Ps2, complete display.

Ps::rase::haracter*

CSI Ps J

PsEL

Sequence

Selectcharacterprotection
attribute *DECSCA

CSI Ps" q

Ps0, DECSED and DECSEL
can erase. (D)Ps

1, DECSED and DECSEL
cannot erase.
2, DECSED and DECSEL
can erase.

Ps
Selectiveerase indisplay*

DECSEDPs

CSI Pn M
Pn lines.

)elete:haracterED

Mnemonic

CSI? PsJ}

nsert line

:rase in
iisplayName

CSI Ps K

0, cursor to end. (D)Ps

1 , beginning to cursor.

Ps2, complete line.

ECH

CSI PnX
Pn characters.

Selectiveerase inline*

0, cursor to end. (D)Ps

1 , beginning to cursor.

Ps
DECSEL2, complete display.
CSI? Ps K

Ps0, cursor to end. (D)Ps

1 , beginning to cursor.

Ps2, complete line.

* Available in VT 400 mode only.
(D) = default.

VT420 Programming Summary

Rectangular Area Control Functions

Name

Mnemonic

Sequence·

Copy
rectangulararea

DECCRA

CSI Pts; PI; Pbs; Prs;
Pps; Ptd; Pld; Ppd $ v

EraserectangularName

Mnemonic

Sequence·

Selectiveerase

DECSERACSI Pt; PI; Pb; Pr $ {Pt

top-line border.

rectangulararea

Selectattributechangeextentlett-column border.

Pbbottom-line border.

Prright-column border.

DECSACE

CSI Ps* xPscharacter positions
affected.
stream of character
positions.

Pts

top-line border.

PIlett-column border.

Pbs

bottom-line border.

oPrsright-column border.

or
1

Pps

source page number.

Ptd

destination top-line border.

Pld

destination left-column
border.

Ppd

destination P!lge number.

Changeattributes in

DECERA

CSI Pt; PI; Pb; Pr $ z

rectangular
area

area

Fill
rectangularPI

Pt

top-line border.

PIlett-column border.

Pbbottom-line border.

Prright-column border.

Reverseattributes in

DECFRA

csi Pch; Pt; PI; Pb; Pr $rectangular
area

x

area
Pch

decimal code of fillcharacter.

Pt

top-line border.

PIlett-column border.

Pbbottom-line border.

Prright-column border.

2

rectangular area ofcharacter positions.

DECCARACSI Pt; PI; Pb; Pr;
Ps1 .. Psn$ r

Pt

top-line border.

PIlett-column border.

Pbbottom-line border.

131

Pr

right-column border.

Psnvisual character attributes

DECRARACSI Pt; PI; Pb; Pr;
Ps1 .. Psn$ t

PtPI·

top-line border.

Pbbottom-line border.

lett-column border.

Prright-column border.

Psnvisual character attributes.

·These sequences work in VT400 mode only.

32

VT420 Programming Summary

Mnemonic

Sequence

Pan downSU

eSI PnS
Pn lines down.

Pan upsD

eSI PnTPn lines up.

Verticalcursorcoupling
mode

DECVCCM

SeteSI ? 61 h
Coupled. (D)Pagecursorcoupling
mode

DECPCCM

Name
Panning *ursor Movement and Panning Sequences.meMnemonic

Sequence

1abling the eursor
xt cursor
lable
;>de

DECTCEM

Set: eSI? 25 h
Visible cursor. (D)Reset: eSI ? 25 I
Invisible cursor.

)ving the eursor*
lck
iext
Irwardiext
Irsor
sitionlrizontal
d verticalsition

DECBI

ESC 6

DECFI

Ese 9

CUP

eSI PI; Pc H
Line PI, column Pc.

HVP

eSI PI; Pc f
Line PI, column Pc.
(Digital recommend
using CUP instead.)eSI PnC
Pn columns right.

Irsor
ward

CUF

Irsor
ckwardIrsor up

CUB

Irsor
wn

CUD

CUU

eSI PnD
Pn columns left.
eSI PnAPn lines up.
eSI PnBPn lines down.

Reset: eSI ? 61 I
Uncoupled.
Set: eSI ? 64 h
Coupled. (D)Reset: eSI ? 64 I
Uncoupled.

*In these sequences, the default value for Pn, PI, and
Pc is 1.
tAvaiiable in VT400 mode only.
(D) = default.

VT420 Programming Summary

133

Sequence

Keyboard Control Sequences

Pcn

control performed.

0

factory default.

CSI2 hLocked.

CSI21
Unlocked.
(D)

Autowrap

DECAWM

function number.
all local functions.
local copy and paste.

AM

DECARMPfn
0

local panning

Reset

Autorepeat

Reset

1

Set

LNM

CSI Pft; Pet; ... Pfn; Pen +q2
3

Mnemonic

Line
feed/
new line

Set

DECELF

SequenceMode

DECBKM

Mnemonicfunctions

Keyboard
actionBackarrowkey

ModeEnablelocal

CSI? 67 h
Backspace.

CSI? 671
Delete. (D)CSI20 hNew Line.

CSI20 ILine feed.
(D)
CSI ?81
No repeat.

CSI? 8 h
Repeat.
(D)
CSI? 7 h
Autowrap.

Cursorkeys

DECCKM

CSI? 1 h
Application.

Keypadapplication/
numeric

DECKPAMESC =Application.

Numeric
keypadDECNKM

CSI? 66 h
Application.

Keyboard
usage

DECKBUMKey
position

DECKPM

CSI? 68 h
Data processing.
CSI81 hPosition
reports.

Localfunctionkeycontrol

1enable local function.

2

disable local function.

DECLFKC

Pkn
0

ESC>
Numeric.
(0)
CSI? 661
Numeric.
(0)
CSI? 681
Typewriter.
(0)
CSI81 1
Charactercodes. (D)Selectmodifierkeyreporting

CSI Pkt; Pft; ... Pkn; Pfn}

F1 or Hold.
F2 or Print.

3

F3 or Set-Up.

4

F4 or Session.

Pfnfunction performed.

0

1

factory default.
local function.

2

send key sequence.

3

disable key.

DECSMKR=

function key number.
all local function keys.

2

1

CSI ?71
No
autowrap.
(D)
CSI? 1 1
Cursor. (D)local window resize.

CSI Pmt; Pft; ... Pmn; Pfn+r

34

VT420 Programming Summary

PI is the loc/,( parameter.

Sequence
lode

xtendedMnemonicSeto or none

Reset

Ky11St 1;... Kyrv'Stn are the key definition strings.

Pmn

key number.

0

all keys.

1left IShiftl.

2

right IShiftl.

Key

Value

Key

Value

Key

Value

3

lock key.

F6

17

F11

23

Do

29

4

@I!!).

F7

18

F12

24

F17

31

5

left I Alt Function I·

F8

19

F13

25

F18

32

6

F9

20

F14

26

F19

33

7

right I Alt Function I·
left I Compose Character

F10

21

Help

28

F20

34

8

. right

The key selector number (Kyn) indicates which key you
are defining.

I·

I Compose Character I·

The string parameters (Stn) are the key definitions,
encoded as pairs of hex codes.

Pencontrol performed.

0

factory default.

3/0 through 3/9 (0 through 9)

1

modifier function.

4/1 through 4/6 (A through F)

2extended keyboard report.

6/1 through 6/6 (a through f)

3

key disabled.

DECEKBD

APC : ppp mm ST~yboardIport

lock the keys.
do neit lock the keys.

ppp

key position number.

mm

modifier key state.

o

not pressed.
pressed.

») = default.

Printing Control SequencesName

Mnemonic

Sequence

Printer extent
mode

DECPEX

Set: CSI ? 19 hPage. (D)Reset: CSI ? 19 I
Scrolling region.

rogramming UDKs
efinable Keys
6 through F14oHelp
F17 through F20

ECUDK Device Control String Format
CS Pc ; PI I Ky11St1 ; ... KynIStn ST
c is the clear parameter.
or noneclear all keys before loading newvalues (default)
clear one key at a time, before
loading a new value.

Print form feedmode

DECPFF

Set: CSI? 18 h
Form feed.
Reset: CSI ? 181
No form feed. (D)VT420 Programming SummaryName

Mnemonic

Sequence

Auto print modeMC

On: CSI? 51
Off: CSI ? 41

Printer controller
mode

MC

On: CSI5 i
Off: CSI4 1

Print pageMCCSI I or CSI 0 I

Print composed
main displayMC

CSI? 10 i

Print all pages

MC

CSI? 11 i

Print cursor lineMC

CSI? 1 i

Start printer-tohost session

MC

CSI? 9 i

Stop printer-tohost session

MC

CSI? 8 i

Assign printer toactive session

MC

CSI? 18 i

Release printerMC

CSI? 19 i

Screen Display Control SequencesName

Mnemonic

Sequence

Send/receive
mode

SRM

Set: CSI 12 hLocal echo off. (D)Reset: CSI 12 I
Local echo on.

Screenmode

DECSCNM

ESC#5

Double-width

ESC #6

Double-width/double-height

Set: CSI ? 5 h
Light background.
Reset: CSI ? 5 I
Dark background. (D)Scrollingmode

DECSCLM

Set: CSI ? 4 h
Smooth scroll. (D)Reset: CSI ? 4 I
Jump scroll.

Send line
attributes
Single-width

135

Selectnumberof lines
per screen

DECSNLS

CSI Pn * I
Pn = number of lines.

Top half

ESC#3

Bottom half

ESC # 4

Select active
statusdisplay"

DECSASD

CSI Ps $ }Ps = 0, main display.
Ps = 1, status line.

Clear all attributes

ESC [0 m
ESC [ OJ Ps; Ps; ...
Psm
Ps = attribute.
See text.

Select statusline type"

DECSSDT

Set attributes

CSI Ps $Ps = 0, none.
Ps = 1, indicator. (D)Ps = 2, host-writable.

Send visualcharacterattributes(D) = default.

'"Available in VT400 mode only.
(D) = default.

136

VT420 Programming SummaryName

Mnemonic Sequence

Tertiary Device Attributes (VT400 Mode Only)

Sequences for VT420 Reports
Name

Mnemonic Sequence

Primary Device Attributes
PrimaryDArequest(Host to
VT420)DA

PrimaryDADA

response(VT420 tohost)

CSI c or CSI 0 c

CSI? Psc; Pst; ... Psn c

TertiaryDArequest(Host to
VT420)
DECRPTUI
response(VT420 to
host)

CSI

DA

DCS! I D.. DST
D.. D = unit ID.

Device Status Reports
VT 420 Operating Status
RequestDSR(Host to
VT420)

61

operating level.
level 1 (VT100 family).

62,63,64 =level 4 (VT400 family).

Ps1 ... Psn=

extensions.

Report(VT420 tohost)

1

132 columns.
printer port.

Cursor Position Report

Psc

2
6

selective erase.

7

soft character set.

8
15

user-defined keys.

18

user windows.

19

two sessions.
horizontal scrolling.

DEC technical set.

21

See Table 9-1 for alias responses.
Secondary Device Attributes
SecondaryDArequest(Host to
VT420)DA

SecondaryDA
response(VT420 to
host)

DA

CSI > c or CSI > 0 c=cor CSI =0 c

DA

DSR

CSI 5 nCSIO nNo malfunction.
CSI3 nMalfunction.

Request(Host to
VT420)DSR

CSI6n

Report(VT420to host)CPRCSI PI; Pc R

PI

line number.

Pccolumn number.

Extended Cursor Position Report
Request(Host to
VT420)DSR

CSI ? 6 n

Report(VT420DECXCPR CSI? PI; Pc; Pp R

to host)PI

line number.

CSI> 41; Pv; 0 c

Pccolumn number.

Pv = firmware version.

Pp

page number.

VT420 Programming SummaryName

Mnemonic Sequence

Device Status Reports

Name

137

Mnemonic Sequence

Device Status Reports

Printer Status
Request(Host to
VT420)

DSR

Report(VT420 to
host)

DSR

CSI? 15 n

CSI? 13 n
No printer.
CSI? 10 n
Printer ready.
CSI? 11 n
Printer not ready.

UDK Status (VT400 Mode Only)
Request(Host to
VT420)

DSR

Report(VT420 to
host)

DSR

CSI ? 25 n

keyboard dialect.

1

North American.

Pst

keyboard status.

0

keyboard ready.

3

no keyboard.

8

keyboard busy.

Ptyp

keyboard type.

0

LK201.

1

LK401.

Request(Host to
VT420)DSR

CSI? 62 n

Report(VT 420
to host)DECMSRCSI Pn * {Pn = number of bytes/16.

CSI? 18 n
Printer busy.
CSI? 19 n
Printer assigned to othersession.

Pia

Macro Space

Memory Checksum
CSI? 20 n
UDKs unlocked.
CSI? 21 n
UDKs locked.

Keyboard Status
Request(Host to
VT420)

DSR

Report(VT420 to
host)

DSR

CSI ? 63; Pid n
Pid = request label.

Request(Host to
VT420)

DSR

Report(VT420 to

DECCKSR DCS Pid! - 0 .. 0 ST

~ost)

CSI? 26 n

Pidrequest label.

D .. D

checksum.

Dat~ Integrity

CSI ? 27; Pia; Pst; Ptyp n

Request(Host to
VT420)DSR

CSI? 75 nReport(VT420 tohost).

DSR

CSI? 70 n
No communication errors.
CSI? 71 n
Communication errors.
CSI? 73 n
Not reported since last
power-up or RIS.

38

VT420 Programming Summarylame

Mnemonic SequenceNamelevice Status Reports
lultiple Session Status:equest-lost to
T420)

DSR

eSI? 85 n:eportDSR

eSI ? 80; Ps2 n
SSU sessions enabled.
Ps2 = Maximum number ofsessions.
CSI ? 81; Ps2 n
SSU sessions available but
pending.
Ps2 = Maximum number ofsessions.

rr420 toost)

eSI? 83 n
SSU sessions not ready.
eSI? 87 n
Sessions on separate lines.

Terminal
state
report(VT420 to
host)
RestoreRequest(Host to
VT420):hecksum

DECROCRAeSI Pid; Pp; Pt; PI; Pb; Pr *y

Pidrequest label.

Pppage number.

Pt

top-line border.

PI

left-column border.

PbPrbottom-line border.
right-column border.

DECCKSR DeS Pid! - D .. O ST

DeS 1 $ s 0 .. 0 ST

0 ... 0 =report data.

OECRSTSDCS Ps $ P 0 ... 0 ST

Ps

data string format.

oerror.

1
0 ... 0terminal state report.
restored data.

OECROPSRCSI Ps $ w
Pso:equesting Checksum ot Rectangular Area~equest

OECTSR

Presentation State Reports (VT4oo Mode Only)

report requested.
error.

2

cursor information report.
tab stop report.

Cursorinformation
report(VT420 to
host)

OECCIRDCS 1 $ u 0 ... 0 ST

Tab stopreport(VT420 to
host)

OECTABSR DeS 2 $ u D ... O ST

RestoreOECRSPS DCS Ps $ t 0 ... 0 ST

1

1T400 Mode Only)-lost toT420)

Mnemonic Sequence

Terminal State Reports (VT400 Mode Only)

0 .. 0=

data string.

See the VT420
Programmer Reference
Manual for description.

0 .. 0=tab stops.

~port

Pid
0 .. 0rr420 toost)

request label.

Ps

checksum.

odata string format.
error.
cursor information report.

erm inal State Reports (VT400 Mode Only)2tab stop report.

lequest0 ... 0 =data string.

-lost to'T420)

DECROTSReSI Ps$ u
Psoreport requested.
ignored.
terminal state report.

VT420 Programming SummaryName

Mnemonic Sequence

Name

Mnemonic Sequence

Mode Settings (VT400 Mode Only)

Control Function Settings (VT400 Mode Only)

Requestmode

Request(Host to(Host to
VT420)

DECROM

CSI Pa $ p

Pa

ANSI mode. (Table 9-2)

VT420)DEC ROSS DCS $ q D... D ST

D.. D

CSI? Pd$ P

PdReportmode(VT420 to
host)

DECRPMPaANSI mode. (Table 9-2)

1, invalid request.

mode state.

D.. D

intermediate and/or final
characters of function.
(Table 9-4)

unknown mode.

1

set.

2
3
4
SM

permanently set.
permanently reset.

Pa

ANSI mode(s). (Table 9-2)

reset.

CSI Pa; ... Pa h

CSI? Pd; ... Pdh

Reset
mode

RM

DEC private mode(s}.
(Table 9-3)
CSI Pa; ... Pa IPa

ANSI mode(s). (Table 9-2)
CSI? Pd; ... Pdl

Pd0, valid request.

Ps

o

Pd

intermediate and/or final
characters of function.
(Table 9-4)

DECRPSS DCS Ps $ r D... D ST

Ps
Ps

Set mode

DEC private mode. (Table 9-3) Report
CSI Pa; Ps $ y(VT420 to
host)

139

DEC private mode(s).
(Table 9-3)

Saving and Restoring the Cursor State

Save
cursor
state

DECSC

ESC 7

Restorecursor
state

DECRC

ESC 8

Window Report (VT400 Mode Only)

Request(Host to
VT420)

DECRODE CSI" v

Report(VT420 to
host)

DECRPDE CSI Ph; Pw; Pmf; Pmt; Pmp"w
Ph

number of lines.

Pw
Pml

number of columns.
first column at left.

Pmt

top line.

Pmp

page number.

140

VT420 Programming Summary

Name

Table 9-2

Mnemonic Sequence

User-Preferred Supplemental Set (VT400 Mode)
Request~Host to
VT420)

DECRQUPSS

ReportDECAUPSS~VT420 to

lost)

rable 9-1

CSI & uMode

DCS O! u % 5 ST
DEC Supplemental Graphic
DCS 1 ! u A ST
ISO Latin-1 supplemental

Alias Primary DA Responses From theVT420

rerminal

Identification
Sequence

Meaning

rf100 DAESC [? 1; 2 c

VT100 terminal

rf101 DAESC [? 1; 0 c

VT101 terminal

rf102 DAESC [? 6c

rf220 DA*CSI ? 62; 1; 2; 6;
7; 8; 9 c

VT102 terminal
VT220 terminal

rf320 DA*
rf420 DA*CSI ? 63; 1; 2; 6;
7; 8; 9 c
CSI ? 64; 1; 2; 6;
7; 8; 9;ANSI ModesforDECRQM,DECRPM,SM,and RM

VT320 terminal

VT420 terminal

15; 18; 19; 21 c
"OTE
ro change an alias response, you must use the~eneral Set-Up screen. See Chapter 5, "Using
Set-Up".
'These responses correspond to the worldwide model)f the terminal. The North American model does not;upport NRC sets (9).

Mnemonic

Sequence

Guarded area transfer

GATM*

1

Keyboard action

AM

2

Control representation

CRMt

3

Insert/replace

IRM

4

Status reporting transfer

SRTM*

5

Vertical editing

VEM*

7

Horizontal editing

HEM*

10

Positioning unit

PUM*

11

Send/receive

SRM

12

Format effector action

FEAM*

13

Format effector transfer

FETM*

14

Multiple area transfer

MATM*

15

Transfer termination

TTM*

16

Selected area transfer

SATM*

17

Tabulation stop

TSM*

18

Editing boundary

EBM*

19

Line feed/new line

LNM

20

*This control function is permanently reset.
tThe host cannot change the setting of CRM. You
can only change CRM from set-up. If CRM is set,
the terminal ignores DECRQM and most other control
functions.

VT420 Programming Summary

Table 9-3

DEC Private Modes for DECRQM,
DECRPM, SM, and RM

Mode

Mnemonic

Pd

Cursor keys
ANSI

DECCKM
DECANM

2

Table 9-4

Control Functions for DECRQSS
Requests

Control Function

Mnemonic

Intermediateand Final
Characters(s)DECSASD$ }DECSACE*x

Scrolling

DECSCLM

ScreenDECSCNM

4
5

Select active status
display
Select attributechange extent

OriginAutowrapDECOMDECAWM

6
7

Set character
attribute

DECSCA"q

Autorepeat

DECARMB" P

DECPFF18

Set conformancelevel

DECSCL

Print form feed

Set columns per
page
Set lines per page

DECSCPP$1

Set number of lines
per screen
Set status line typeDECSNLS* 1

DECSSDTSet left and rightmargins

DECSLRM$s

Set top and bottom
margins

DECSTBM

Select graphic
rendition
Enable local
functions
Local function key
control

SGRm

DECELF+q

DECLFKC=}

Select modifier key
reporting

DECSMKR+r

ColumnDECCOLM3

Printer extent

DECPEX

19

Text cursor enable
National replacement
character set

DECTCEMDECNRCM

25
42

Horizontal cursor
coupling

DECHCCMt

60

Vertical cursor coupling

DECVCCM

61

Page cursor coupling

DECPCCM

64

Numeric keypad

DECNKM

66

Backarrow key

DECBKM

Keyboard usage

DECKBUM

67
68

Vertical split
screenDECVSSM

69

Transmit rate limiting

DECXRLMDECKPM

73
81

Keyboard position

tThis control function is permanently reset.

141

DECSLPP142

VT420 Programming Summary

Soft Terminal Reset (DECSTR) States

Mnemonic

State After
DECSTR

Text cursor enable

DECTCEM

Cursor enabled.

Insert/replace

IRM

Replace.

OriginDECOM

Absolute (cursor
origin at upper-leftof screen).

Modelesetting and Testing Sequenceslame

Mnemonic

Sequence

lesetting the Terminal.oft terminal

DECSTR

CSI !pRIS

ESC c
Not recommended.

ecure reset

DECSR

ESC [Pr+ p
Pr can be any number
from 0 to 16383.

ecure reset::mfirmation

DECSRCESC [Pr * q
Pr can be any number
from 0 to 16383.

~set*lard terminal~set:ibulation
ear

TBC

CSIO 9Clear tab at cursor
position.

Autowrap

DECAWM

No autowrap.

National
replacement
character set

DECNRCM

Multinational set.

Keyboard action

AM

Unlocked.

Numeric keypad

DECNKM

Cursor keys

DECCKM

Numeric
characters.
Normal (arrowkeys).

Other Conttol Functions
DECSTBMAll character sets

GO, G1,G2, G3,
GL, GR

Select graphic
rendition

SGR

Normal rendition.

Select character
attribute

DECSCA

Save cursor state

DECSC

Normal (erasable
by DECSEL and
DECSED).
Home position with
VT420 defaults.

DECAUPSS Set selected in
set-up.

CSI3 9Clear all tabs.
esting the Terminal
creen·ignment
splay

DECALN

Ivoke)nfidence
1st

DECTST

ESC

8

CSI4j Pst; .. .Psn y

Top margin = 1.
Bottom margin =page length.
VT420 default
settings.
(DECSTR works
only in VT400
mode.)

Set top andbottom margins

1

power-up self-test.

Assign userpreferredsupplemental
set

3

printer port
loopback.

Select active
status display

DECSASD

Main display(first 24 lines).

7

DEC-423 port
loopback.

Keyboard positionmode

DECKPM

Character codes.

9

repeat tests.

Ps

test to run.

0

all tests.

I'l.vailable in VT420 mode only.

VT420 Programming Summary

Enable Session Command
CSI&x

Sequence

ActionESC A

Cursor up.
Cursor down.

ESC B
ESCC
ESC D
ESC F
ESCG
ESCH
ESC I
ESCJ

Cursor right.
Cursor left.
Enter graphics mode.
Exit graphics mode.
Move the cursor to the home position.
Reverse line feed.
Erase from the cursor to the end of thescreen.

ESC K

Erase from the cursor to the end of theline.

ESC Y Pn
ESCZ
ESC/Z
ESC =

Move the cursor to column Pn.
Identify. (host to terminal)

ESC>
ESC <
ESC A
ESC

Report. (terminal to host)Enter alternate keypad mode.
Exit alternate keypad mode.
Exit VT52 mode. (Enter VT100 mode.)Enter autoprint mode.

ESCW
ESC X
ESC]

Exit autoprint mode.
Enter printer controller mode.
Exit printer controller mode.
Print the screen.

ESC V

Print the line with the cursor.

143

This chapter describes what to do if you have a problem with the VT420.
The chapter also describes the terminal's power-up self-test and screen
error messages.

Operating Problems
Table 10-1 lists some possible operating problems and their suggested
solutions. Check this list before calling for service. If you need service,
see the "Digital Service" section in this chapter..

Power-Up Self-Test
Every time you turn the terminal on, the VT420 automatically runs apower-up self-test. This test checks the operating status of many of theterminal's internal parts.

Successful test: If the test is successful, a VT420 OK message appears on
the screen. The keyboard bell should ring once.

Error: If the keyboard bell does not ring or it rings similar to a telegraphsound, this indicates a self-test error. The keyclick and bell soundpatterns are codes that provide service personnel with information about
the terminal's operating condition.

144

Solving Problems and Getting Service

145

Error Messages
If the VT420 fails the power-up self-test, the terminal may display one of
the error messages in Table 10-2. Only qualified service personnel should
try to correct these problems. If possible, note the error message thatappears, then call for service.
Table 10-1

Common Operating Problems

Problem

Suggested Solution

The VT420 does notturn on when you set
the power switch to 1
(on).

Make sure the VT420 power cord is plugged into thewall outlet. Check the power at the wall outlet byplugging in a lamp.

The screen's text is notbalanced on the lEdt
and right or top andbottom.

Align the text by using the screen align feature in
the Set-Up Directory screen (Chapter 5).

The printer does notprint.

Make sure the printer is plugged in and its powerswitch is on. Make sure the cable connection between
the printer and VT420 is tight.
Make sure the printer assignment feature in Global
Set-Up is set to the active session (Chapter 5). If thesetting is correct, Printer: Ready should appear on
the status line at the bottom of the screen.
Make sure all communication settings on the terminaland printer (such as transmit rate, receive rate, andparity) match.

Data on the screen
does not scroll. The
Hold indicator is on.

Press the ~ (Hold) key to resume scrolling.

The keyboard seems
to be locked (the Wait
indicator may be on),and the VT420 cannot
receive data from thehost.

Clear the terminal by using the Clear Comrn field in
the Set-Up Directory screen (Chapter 5).

146

Solving Problems and Getting Service

Table 10-1 (Cant.)

Common Operating Problems

Problem

Suggested Solution

The screen is blank,
except for a blinking
cursor at the lowerright corner of thescreen.

The CRT saver feature in the Global Set-Up screen(Chapter 5) may be on. Press any key to reactivate
the screen display.
Make sure the brightness and contrast controls(Chapter 4) are adjusted correctly.

The bell tone does notring when you turnthe VT420 on. The
keyboard indicatorlights do not flash.

Make sure the keyboard is connected to the terminal.

The host system's
software does notrecognize the VT420
terminal type.

Change the setting of the terminal ID feature in the
General Set-Up screen (Chapter 3).

Power to the terminal
is lost, and you cannot
log in to your hostsystem.

When power is restored to the terminal, make the~ (Set-Up) key the first key you press. Refer to
Chapter 7 for the procedure to restore an interrupted
session.

Table 10-2 Screen Error Messages
Error Message

Problem and Solution

VT420 NVR

Nonvolatile memory (set-up storage) is
not operating. Turn the terminal off andon. When you turn the terminal on, theset-up features will return to the default
state. If the problem continues, call Digital
Customer Services.

Error - 1

Solving Problems and Getting Service

Table 10-2 (Cont.)

147

Screen Error Messages

Error Message

Problem and Solution

VT420 Keyboard
Error - 4

1. Make sure your keyboard is plugged in.
If it is,2. Turn the terminal off and on.
If the problem continues,
3. Try another keyboard, if you have one.
If the new keyboard works, replace
the old keyboard.
4. If the new keyboard does not work,
the problem is inside theCall Digital Customer Services.

VT420 DEC-423 Port
Error - 5

The problem is inside the terminal.
Call Digital Customer Services.

VT420 Printer Port
Error - 6

The problem is inside the terminal.
Call Digital Customer Services.

The keyboard's keyclick andmargin bell make sound patterns
similar to a telegraph.

The problem is inside the terminal.
Call Digital Customer Services.

Digital Service
Digital provides a wide range of maintenance programs that cover small
systems and terminals. These include on-site, carry-in, and mail-in repair
services. You can use these programs to select a plan that best meets yourservice needs.

On-Site Hardware Services
Digital offers fast, low-cost, quality maintenance performed at your site
by Digital-trained Service Specialists. There are several on-site services
available.
DECservice

DECservice provides preferred on-site service, with a guaranteed responsetime when equipment is located within a specified distance of the service
facility. DECservice guarantees a continuous repair effort until service isrestored. You can choose the hours of coverage, up to 24 hours a day, 7days a week.

148

Solving Problems and Getting Service

Basic

Basic offers priority response during regular business hours, Monday
through Friday.
Site SERVlcenterIf you have at least 50 terminals and can provide workspace at your site,
Digital will provide an on-site technician for a predetermined, periodic
time interval. The terminals can include a variety of models (for example,
VT200s, VT300s, and VT420s).
Per CallThis noncontractual offering provides on-site repair based on time andmaterials. Per call service is available during regular business hours,
Monday through Friday.
DECallDECall is similar to per call service, but has an annual retainer fee.
DECall gives you on-site service at a fixed fee per repair call.

Off-Site Hardware Services
Carry-In SERVlcenters

Digital SERVIcenters are located in major cities around the world. They
offer convenient, cost-effective repair service with a 48 hour turnaroundtime. Both contract and per call coverage is offered.
DECmailer

DECmailer is a mail-in service for module and subassembly repairs.
DECmailer provides five day turnaround and express 24 hour turnaround.

Software Service
Software service products are available for host resident applications.

How to Get Service
Digital has a central service center in your area to help you keep yoursystem running at peak efficiency. To find out more about Digital's
hardware and software service offerings

Solving Problems and Getting Service

149

In the United States

Call 1-800-554-3333 during regular business hours and ask for Customer
Assistance.
Outside the United States

Contact your local Digital Customer Services Office.

This appendix lists the specifications for the North American version of
the VT420 video terminal.

Site Planning
VT420 Terminal(Approxim.ate Size)

Height282mm(11.1 in)

Width

320mm

(12.6 in)

Depth

331mm

(13.1 in)

Weight8 kg(17.5Ib)

Tilt-swivel

60 degrees

Adjustable tilt

+5 to -20 degrees

LK401 Keyboard(Approxim.ate Size)

Height4mm(1. 75 in)

Width

48mm

(18.8 in)

Depth

19mm

(7.5 in)

Weight7 kg(3.1 lb)

150

Specifications

151

Operating Environment
Temperature

10 0 to 40 0 C (50 0 to 104 0 F)

Relative humidity

10% to 90% relative .humidity with a maximum wet bulb
of 280 0 C and a minimum dew point of 2 0 C

Altitude2400 m (8000 ft) maximum

Electrical
AC input

No selection required. 125 V nominal, single-phase,2-wire plus safety earth groundLine frequency

50 to 60 Hz nominal

Input power

67 watts

Power cord

Rated 125 V, listed, type SJT/SVT, 18 AWG-3 wire

Display
Active video area

(approximate size)

Horizontal

232 mm (9.04 in)

Vertical

168 mm (6.55 in)Format24, 36, or 48 lines of 80 or 132 characters

Built-in charactersets

DEC Multinational character set
U.S. ASCIIDEC Supplemental
ISO Latin Alphabet No. 1
ISO Latin-1 Supplemental
DEC Special Graphics
DEC TechnicalVideo attributes

Normal, bold, underline, blinking, and negative image(reverse videoHelected individually or in combination

Text cursor

Blinking or steady block or underline

Frame rate

70 Hz (60 Hz optimal)

Antiglare

Integral with CRT

152Specifications

LK401 Keyboard
GeneralGeneral108 sculptured keys with matte finish
Available in a word processing version.

Cord

1.8 m (6 ft) coiled cord with a 4-pin telephone-type
modular connector

Indicator lights

2 keyboard indicators:

[0]

Hold

~

Lock

Keys

(Approximate Size)

Home row

30 mm (1.18 in) above desktop

Key size

13 mm (0.50 in) square

Key spacing.

19 mm (0.75 in) center to center (for single-width keys)

Numeric keypad

18 keys

Function keys

5 predefined keys, 15 user-definable keys

Audible Indicators

KeyclickSounds after each keystroke.

Margin bell

Rings once when cursor approaches right margin.

Warning bell

Rings once for com pose errors.
Rings twice for errors in ser-uTI'
Rings once upon receipt of Ctrl ~You can order the following modems, cables, and manuals from Digital for
the North American version of the VJ.'420. See the end of this appendix
for ordering information.

ModemsPart Number

Description

DF242 ScholarPlus

300, 1200, and 2400 baud, full-duplex asynchronous

DF224

300, 1200, and 2400 baud, full-duplex, asynchronous

DF124

300, 1200, and 1200 baud, full-duplex, asynchronous

153

154

Supplies and Documentation

CablesPart Number

LengthConnector

Printer Cables and Adapter (VT420 to printer)
BC16E-10
BC16E-25

10 it (3 m)
25 it (7.6 m)

6-pin M DEC-423 to
6-pin M DEC-423
6-pin F DEC-423 to
25-pin F RS-232

H8571-A adapter
Null Modem Cables

25-pin F RS-232 to
25-pin F RS-232

BC22D-xx

Communication Cables and Adapters
BC16E-10
BC16E-25

10 it (3 m)
25 it (7.6 m)

H8571-C adapter
H8571-F adapter

6-pin M DEC-423 to
6-pin M DEC-423
25-pin F RS-232 to
6-pin M DEC-423

M = male. F = female.
xx = length in.feet (10, 25, 50, 100,200, 250)

Related Documentation
You can order the following VT420 documents from Digital:
VT420 Programmer Reference Manual

EK-VT420-RM

This manual provide information on character processing, character codes, andcontrol functions that programmers can use for VT420 applications.
VT420 Service Guide

EK-VT420-PS

This guide provides service personnel with the information needed to test,
troubleshoot, and repair the VT420 monochrome video terminal.
Guide to Using VMS

AA-LA05A-TA

Supplies and Documentation

Installing and Using the Session Support
Utility155

AA-JB84B-TE

This guide provides system managers with instructions for installing SSU
software to support two sessions over a single communication line. The guideis part of an SSU software kit. The kit is available on different media.
Magtape

OO-QnZAV-HM*

RX50

OO-QnZAV-H3 ..

TKSO

OO-QnZAV-H5 ..

• n = processor number.

Ordering Information
You can order modems, supplies, and documentation by phone or by mail.
Continental USA and Puerto RicoCall 800-258-1710 or mail to:
Digital Equipment Corporation
P.G. Box CS2008
Nashua, NH 03061
New Hampshire, Alaska, and Hawaii

Call 1-603-884-6660.

This appendix provides information on how the VT420 communicates witha host computer, printer, or modem. The appendix shows the cables you
can use for different system configurations. It describes how XON andXOFF characters help control data flow. The last section describes thesignals carried by the connectors on the rear of the terminal.
The terminal operates on full-duplex asynchronous lines only, with 10
possible transmit and receive speeds. You can use split transmit andreceive speeds, but you must use the same speeds as your host systemand printer.
To match your host system's speed, use the Communications Set-Up
screen (Chapter 5). To match your printer's speed, use the Printer Set-Up
screen (Chapter 8).
For more information on communication, see the VT420 Programmer
Reference Manual.

Cables
You can connect the VT420 directly to a local host system with a cable.
You can also connect the terminal indirectly to a remote host system using(1) a terminal server, or (2) a modem or acoustic coupler connected to
public-switched or dedicated telephone lines. See "Modems" in Chapter 8.
Figure C-1 shows the DEC-423 cables you can use to connect the VT420
to a host system or printer. To order cables, see Appendix B.

156

Communication

6-Pin Comm2(Printer) Port
H8571-A
Adapterf/);;;}

S1llT1:r.:ir-----BC 1 6 E Cable--------~

6-Pin
Comm Portl{j;;]

Printer

H8S71-C or -F
Adapter~

BC16E Cable-----~L. ~odem

6-PinComm Port

H8571-C or -F
Adapter
BC16E Cable

BC22E Cable+--_____
-+M F

r
Host
L.

6-Pin
Comm Port

BC16E Cable

H8571-C or -F
Adapter
Null
Modem Cable
BC22D-xx

Figure C-1

Cablesr+--------fF MHos t
L.

157

158

Communication

XON/XOFF Flow Control
Normally, the VT420 processes and displays characters as fast as it
receives them. If the host system sends data faster than the terminal candisplay it, the terminal can use XONIXOFF flow control to tell the host to
wait until the terminal has caught up.
The VT420 stores incoming characters in a 254-character input buffer.
When the buffer fills to a predetermined level (XOFF point), the terminal
sends an XOFF character to stop the host system from sending morecharacters. When the buffer empties to an appropriate level (XON point),
the terminal sends an XON character to tell the host system to resume
sending characters.
If the terminal is set up to run one session, you can select a first XOFF

point of 64 or 128 characters (Communications Set-Up screen). The XON
point is 32 characters. If the host system fails to respond to the first
XOFF character, the terminal sends another XOFF character when thebuffer fills to 220, and when the buffer is completely full.
If you use SSU software to run two sessions, you can select a first XOFF
point of 64, 256, or 1792. SSU provides its own credit-based flow control,
so XOFF is not needed.
For normal interactive use, you should use the default XOFF point of
64 characters. This setting· prevents the host system from getting too
far ahead of what is displayed on the screen. In some cases, using an
XOFF point greater than 64 characters may improve the average speed
for processing characters, since the host does not have to wait as often.
Hold Screen Function

If XONIXOFF flow control is enabled:
ICtrq @] ~OFF)

Puts the screen display on hold.

ICtrl! [§J (XON)

Releases the screen display.

If XONIXOFF flow control is disabled, you cannot use ICtrli @] and ICtr11@] to hold and release the screen. Instead, the keys will send theircorresponding codes to the host system.
Notes on Using the VT420 Without XON/XOFF Flow Control•

If you disable XONIXOFF flow control, the terminal's receive input
buffer can overflow if the host system sends data faster than theterminal can process and display it.

Communication 159•

The VT420 can process text (without ESC sequences) at approximately
2000 characters/second. This rate allows the VT420 to communicate
at 19,200 baud. Some editing functions, such as inserting or deletingcharacters in lines, require additional time to process. The 254character input buffer allows for short bursts.
For extensive editing, the host system should be programmed to insert
fill characters (NULs) after editing sequences. If the host system is
not programmed, you should reduce the terminal baud rate to 9600
baud or less. See the Communications Set-Up screen in Chapter 5.

•

Selecting one of the smooth scroll settings in the Display Set-Up
screen slows the screen display for easy reading. In order for thesmooth scroll setting to work properly at high speeds, you must have
XONIXOFF data flow enabled.

Modem Connections and Disconnections
When the VT420 makes a connection to the host system through amodem, the terminal performs the following operations to ensure it isready to send and receive:•

Unlocks the keyboard (if it was locked).

•

Clears any transmission in progress.

•

Clears the keyboard buffer and all message buffers.

•

Clears the input buffer.

•

Clears XOFF sent and XOFF received flags.

Any of the following conditions will disconnect the connection to the hostsystem:•

You type [$hili] ~ (Break).

•

You use the Recall or Default fields in the Set-Up Directory.

•

The terminal loses the data set ready (DSR) signal.

•

The terminal loses the receive line signal detect (RLSD) signal forthe period of time you selected in set-up. See the disconnect delay
feature in the Communications Set-Up screen.

•

The terminal receives a self-test command from the host system.

The.usual way to disconnect communications is to type·IShiftl ~ (Break).

160

Communication

Break Function
A break condition is the occurrence of a continuous space on acommunication line for greater than one character time. Some systems
and communication equipment recognize break as a special attention
signal.
You can generate a break signal (275 ms space) by pressing ~ (Break),unless you have changed the function of the ~ key (Keyboard Set-Up
screen).
Changing the terminal comm ports feature setting from Sl=Comml to
one of the two-session configurations also generates a break signal. Thisaction alerts the host that the session configuration has been altered.
The ~ (Break) key has three functions when used as a break key.
~ (Break)Sends a break signal to the host.

!Shift! ~(Break)Disconnects communications when you use a modem.

!Ctrll~Sends the answerback message (Communications Set-Up
screen) to the host.

(Break)Connector Signals
The VT420 has two 6-pin connectors on the rear of the terminal. Bothconnectors can be used as host system (Comml or Comm2) connectors,
and one of the two can be used as a printer connector (Comm2). Bothconnectors use the same signals. Table C-l describes the signals.
Figure C-2 shows the pin numbers for the 6-pin connectors.

2

4

3

}

J"-

r-"'"

~y
~

"""--

~

6

'--

~

GSF_1383_89.DG

Figure C-2

6-Pin Connector Pinouts

Communication

161

I

Table C-1

6-Pin DEC-423 Connector Interface Signals (Comm 1 orComm 2)
Mnemonic

Description

DTR

From VT420
When on, tells the modem or printer that theVT420 is ready to send or receive.

10~1

Data
terminal
ready

Z (~>!l.).. 2

Transmit- TXD+
ted
data

7°'fl--. 3

From VT420
Sends serial characters. H~ld in the mark state(-) when characters are not being sent.
In modem control modes, sends data only when
DSR and DTR signals are on.

LTransmit
signalgroundTXD-

Provides the common ground reference potential
for transmitted signals TXD+ and DTR.

4

ReceivesignalgroundRXD-

Provides the common ground reference potential'for received signals RXD+ and DSR.

~~\~ 5

Received
data

RXD+

From VT420
Receives serial characters.

Data
set
ready

DSR

To VT420
From the modem: When on, tells the VT420
that it has a call connected.

'-g~
,'/

From the printer: When on, tells the VT420
that the printer is ready to print. The tenninal
checks for DTR from the printer before each printo'peration.

Standards
The VT420 operates in accordance with the following national andinternational communication standards:

EIA 232-D
CCITTV.24
CCITT V.2B
CCITT V.lO

ISO 2110.2

Action field

Terminal features in set-up that make the VT420 perform an immediate
action.
Active session

The session that you are currently using on tlie VT420. You use the(Session) key to change the active session.

aApplication software

A program that performs a specific function for a particular class ofcomputer users. Examples: spreadsheet applications, word processing
applications, text editing applications.
Auto print mode

A method of printing information directly from the host system. The
VT420 sends a display line to the printer after a carriage return or form
feed character.
.
Bottom margin

The last line of the scrolling region.
CCITI

Comite Consultatif International de Telegraphique et Telephonique(International Telegraph and Telephone Consultative Committee). A
standards committee for the communication industry in Europe.
Character set

A group of graphic characters and control characters stored as a unit in
the terminal. Graphic characters are characters you can display. on thescreen. Control characters perform special functions.
162

GlossaryGlossary 163

Compose character

A character produced when you press two or three keys in a certain
sequence. You can use compose sequences to produce characters that do
not appear as standard keys on your keyboard.
Current pageThe page in page memory that the cursor is on.
CursorAn indicator that highlights the active position on the screen. The VT420
uses different cursor characters for text and set-up.
Data processing keys

Keys that have characters on the left half and right half of their keycap.
The characters on the right half of the keycap are data processing
characters. You must select a special set-up feature to use thesecharacters.
Diacritical marks

Marks or symbols that indicate a change in the standard pronunciation of
a letter. Examples of diacritics are the acute accent ( , ), grave accent ( , ),and tilde (-).
On the VT420, you can use diacritical marks (if available on yourkeyboard) to start two-stroke compose sequences.
Display

The information that appears on the screen.
Factory default

A standard setting for a feature. The VT420 uses factory-default settings,
unless you select a new setting. Many set-up features have default
settings.
Full-duplex modem

A modem that can handle simultaneous, two-way communications.
Host system

The computer system(s) you connect to the VT420. If you connect theterminal to two systems, one is the primary host and one is the secondary
host.

164

Glossary

Inactive session

A session that you are not currently using. You can run two sessions at
the same time on the VT420, but you can only interact with one session
at a time.
Keyboard indicator line

A status line with six fields that provide information about the keyboard's
status. The keyboard indicator line appears at the bottom of the screen,in the smaller, 132-column font. See also status line.
Modem

Modulator - demodulator. A device that converts data from a computeror terminal into signals that can be sent over a telephone line.
Modifier key

A key pressed in combination with another key, to modify the code sent bythat key. letr" is a modifier key.
Nonvolatile memory

Nonvolatile RAM (random access memory). The VT420 uses this memory
to store the saved settings of set-up features. The settings are not lostwhen you turn the terminal off.
Page

A section of the terminal's page memory. Each page has left, right, top
and bottom margins. You can define the size and layout of a page by using
the page arrangement feature.
Page arrangement

A set-up feature that divides page memory into one of four standard page
sizes. The default setting of the page arrangement feature is 3 pagesof 24 lines each (for two sessions) or 6 pages of 24 lines each (for a single
session).
Page memory

Memory in the VT420 that can store the information you enter from the
keyboard. The total size of page memory is 144 lines. Page memory is
divided into pages. You can select from several standard page sizes. The
amount of memory available depends on the page size selected and thenumber of sessions used (one or two).

Glossary

1 65

Panning

Pointing a window to display different parts of page memory. Panning awindow is similar to panning a camera. The window does not move on thescreen; you point the window at another location in page memory.
Pixel

Picture elements. The smallest displayable unit on a video screen. To
display a character, the terminal turns on a series of pixels.
Port

The logical route for data in or out of the controller board on the VT420.
Also, another term for connector. One port can support one or moreconnectors. All the VT420 connectors are on the rear of the terminal.
Prefix key

A key that you press and release before r"-::.--'---.s.I-'-'""""'=:---'-----"\
the function of one or more keystroke,s.
~-~-----~
key.
Resynchronize

To restore communication with an interrupted session.
Saved setti ngs

The settings of set-up features that the VT420 uses when you turn theterminal on. You can change these settings or use the factory-default
settings.
Scrolling

Moving data between the margins of the page currently displayed. Data
scrolled past the margins is lost from page memory, but usually not fromthe host system.
Scrolling region

The area on the current page that is between the top, bottom, left, andright page margins. The default scrolling region is the complete page.
Only a programmer can change the page margins.
SessionAn active connection between the VT420 and a host system. When you log
in to a computer from the terminal, you open a session.

166 Glossary

Set-upA set of display screens on the VT420 that let you examine and change thesettings of the terminal's operating features. You can use the keyboard tochange settings.
SSU

Digital's Session Support Utility. This software lets you run two sessions
over one communication line.
Status line

A display line that provides information about the session's current
operating state. The status line appears at the bottom of the screen
or at the bottom of the session (if you are running two sessions). The
VT420's status display feature has three settings-indicator, none, andhost-writable. The VT420 always displays the status line for the current
session in set-up.
Terminal server

An intelligent unit that can connect a number of asynchronous devices(terminals and printers) to a host system. For example, Digital's
DECserver 200 can link eight VT420 terminals to a system in a local
area network (LAN), using a high-speed Ethernet cable.
User-defined keys (UDKs)

Any of the 15 keys, ~ to IF20 I, on the top row of the keyboard for which auser has defined special functions. You can use UDKs to store. frequently
used text and commands.
Visual character attribute

A quality of a display character that highlights the character, such as
bolding and underlining.
Window

A specified area of the screen used to display information from page
memory. You can divide the screen horizontally into two windows, todisplay information from two sessions. at the same time.

IndexA

I Alt Function Ikey
set-up feature, 75
Answerback message
sending, 43
Arrow keys, 39
Audible indicators, 45
Auto answerback message, 73
Auto repeat feature, 74
Auto resize screen feature, 66
Auto wrap feature, 64

B
Backarrow key, 75
Baud rate, setting the, 30
Bell, 45
Break key
See ~key
Brightness and contrast, 17cCables, 154, 156
connections, 18 to 21
Caps/shift lock feature, 74
Character mode feature, 75
Character set
ISO Latin-I, 7
Character sets, 7, 113 to 115
DEC Multinational, 7, 67, 113
DEC Special Graphics, 114

Character sets (cont'd;)
DEC Supplemental character set,
113
DEC Technical, 115
display controls font, 119
ISO Latin-I, 67
selecting, 67
U.S. ASCII character set, 113
UPSS feature, 70
Clear Comm feature, 55
80/132 column mode, 63Comma and period keys, 77
Common problems, 145
Communication, 156 to 161
break function, 160
clearing, 55
modem connections, 159
standards, 161
XONIXOFF flow control, 158
Communication ports, 18
Communications Set-Up screen, 71
Components, 1
I Compose Character \ key, 38
set-up feature, 75
Composing characters, 79 to 86
canceling a sequence, 81
hexadecimal sequences, 81
Computer systems
connections, 3Connectors, 18
Control representation mode, 63
Copying and pasting text, 5, 102
CRT saver feature, 61\Ctrq key, 37

Index

167

168

Index

Cursorin windows, 98
Cursor key mode, 69
Cursor set-up features, 64

H
Hold key
See ~keyoData bits/parity feature, 72
for printing, 110
DEC Multinational character set 7,
67, 113'DEC Special Graphics character set,114
DEC Technical character set, 115
Default settings, recalling, 56
Displaying control characters, 63
Display Set-Up screen, 62
Documentation, 154

E
Emulating VT series terminals 6/Enter/ key, 40'
Error messages, 145, 146

F[EII (Hold) key, 41
set-up feature, 75~ (Print) key, 42
set-up feature, 76~ (Set.-Up) key, 42
set-up feature, 76~ (Session) key, 42
set-up feature, 76~(Break)key, 43,160
set-up feature, 76
Function keys, 41

GGeneral Set-Up screen, 67
Global Set-Up screen, 60

Indicator lights, 44
Installation, 11 to 22
ISO Latin-1 character set, 7, 67

K/# £/ key, 36, 38, 77
set-up feature, 75<> key, 77
Keyboard, 35 to 46
connection, 14
editing keypad, 39
indicator lights, 44
main keypad, 36
numeric keypad, 40
special-function keys, 37
top-row function keys, 41
word processing version, 50
Keyboard indicator line, 6,46
in set-up, 54
Keyboard Set-Up Screen, 74
Keyclick, 45
set-up feature, 74
Keypad mode, 69

LLight/dark screen, 64
Lines/page, 65
Lines/screen, 65
selecting, 95
Local echo feature, 72
Lock key, 37

MMargin bell, 45IndexMargin bell (cont'd.)
set-up feature, 75
Modem control feature, 73
Modems, 153
connections, 111, 159

N
N umber of lines/screen, 62oOn-linellocal feature, 60

pPage arrangement feature, 65Page coupling feature, 66
Page memory, 5Page size, 62Panning, 63, 100
procedure, 100
set-up features, 66
Power-up self-test, 144
Printed data type, 110
Printer assignment feature, 61
Printers, 105
Printer Set-Up screen, 108
Printer to host comm feature, 109
Print extent feature, 110
Printing
connecting a printer, 106
in two sessions, 108
pages (normal mode), 106
selecting a print mode, 106setting up the printer, 107
text from system (auto printmode), 107
under host control, 107
Print key
See ~key
Print mode feature, 109
Print terminator, 110
Problem solving, 22

169

Programming
character encoding, 113 to 120
character sets, 122 to 128
control characters, 115 to 117
cursor movement and panning,132
display controls font, 119
editing sequences, 130
emulating VT series terminals,
122
keyboard, printing, and display,
133 to 135
keyboard codes, 120 to 121
macro commands, 118
page memory, 128 to 129
rectangular area operations, 131
reports, 136 to 141
resetting and testing theterminal, 142
soft character sets, 123 to 128
visual character and line
attributes, 129

R
Recall feature, 56
Receive speed, 72
for printing, 109
Reset session feature, 56
IReturn Ikey, 38
new line set-up feature, 69sSave (settings) feature, 56
Screen alignment, 6, 56
Screen background, 6
Screen display
number of lines, 5
Screen refresh rate, 61Service, 147 to 149
Session key
See [B] key
Sessions

170

Index

Sessions (cont'd.)checking the active session, 94
description, 86
disable sessions feature, 57
enable sessions feature, 57
lines/page, 65
setting up the VT420, 24 ~o 30
setup for one session, 24
setup for two sessions, 26, 28
tenninal comm ports feature, 24
Set-up, 3, 51 to 78
changing settings, 58
Communications Set-Up, 71
cursor, 54
Display Set-Up, 62
entering and leaving, 53
General Set-Up, 67
Global Set-Up, 60
Keyboard Set-Up, 74
overview, 51
Printer Set-Up, 108
recalling saved settings, 59
saving settings, 59
selecting screens, 57
Set-Up Directory, 53
Tab Set-Up, 77
Set-Up key

See~key
Shift I key, 38

1

Smooth/jump scroll feature, 64
Solving problems, 144
Specifications, 150 to 152
SSU software, 28,89
restoring SSU sessions, 93
screen and error messages, 93
Status line, 5,47
set-up feature, 64
Stop bits feature, 72
for printing, 110TlTabl key, 37
Tab Set-Up screen, 77

Terminal comm ports feature, 60,
160
TerminalID
selecting, 31
set-up feature, 68
Terminal mode feature, 68
Terminal servers
setting up for two sessions, 91
Transmit rate limit, 73
Transmit speed, 71
for printing, 109
Two sessions, 4cable connections, 20 to 21
Global Set-Up, 60
independent setups, 52
opening, 87 to 94
with a terminal server, 91
with SSU software, 89
printer assignment, 108setting up the VT420, 24 to 30
setup, 26, 28uUpdate method feature, 70
UPSS feature, 67, 70
User-defined keys, 44
User defined keys lock feature, 69
User features locked feature, 69
User-preferred supplemental sets
See UPSS feature.

v
VT420
features, 3
overview, 1 to 8
specifications, 150 to 152
VT52 mode, 143w
Warning bell, 45
set-up feature, 75IndexWindows, 4, 96 to 100
changing sizes, 99
keeping the cursor visible, 98
selecting, 97
tips on using, 99

x
XOFF feature
for printing, 109
for system communication, 72

171

VT420 Common Keyboard Functions
Set-Up Keys (Chapter 5)

ISet-Up IEnter and leave set-up.

Arrow keys

Move the set-up cursor to different features in a set-up
screen.

IEnter Ior IReturn I

Perform an action or change the setting of the featurethat the set-up cursor is on.

ICtr1l1 Set-Up

I

Reset most set-up features for both sessions to their
saved setting. This key sequence only works in set-up.

Printing (Chapter 8)~ (Print)

Print the page of text that the cursor is on.

ICtrq ~ (Print)

Turn auto print mode on or off. Print each line of text as
it is received from the host system.

Two Sessions (Chapters 3 and 7)~ (l?ession)

Change the active session.

~ (Hold)

Hold the screen display of the active session. Pressagain to release.

ICtrll ~ (Hold)

Hold the screen display of the inactive session. Pressagain to release.

Windows (Chapter 7)
ICtr11 ~ (Session)

Select one or two windows on the screen. Press
One time:

two horizontal windows

Two times:

one full-screen window

Change the relative size of two windows.

Panning (Chapter 7)
ICtrll rn or II]

Pan up and down.

ICtrlllPrevl

Pan to the previous page.

ICtrlllNextl

Pan to. the next page.

Copying and Pasting Text (Chapter 7)
Press and hold the ~ (Copy) key. While holding the ~ (Copy) key, use
the following keys to cut and paste text:

I arrow keys I

Move the cursor to beginning or end of text to be copied.

~

Select the starting point of text to be copied.

I Remove I

Remove the selected text and put it in the paste buffer.
Paste the copied text into the active session, at the
cursor's current position.

Typing Additional Characters (Chapter 6)
Compose Character

I Lets you enter additional characters (Table 6-1) that do
not appear on your keycaps.

Function Keys (Chapter 4)
Perform application-defined functions.
Perform user-defined functions .. To define keys, see theVT420 Programmer Reference Manual.

Communication (Chapters 4,5,8, and Appendix C)~ (Break)

Usually ends communication with a session.

IShift I~ (Break)End communication with a modem ..

ICtr11 ~ (Break)Send the answerback message to the active session.