IBM 3174 Reference Guide

Using Your Terminal as a DEC VT220
BREAK Function
The BREAK function acts differently depending on the application program that
your system is using. This function produces a short break of 0.2333 second; a
Shift BREAK function produces a long break of 3.5 seconds. See your system
administrator for more information.
The CTRL BREAK function generates the answerback message of VT200 EMULATION
ANSWER BACK MSG.
Control Mode/Control Shift
Control functions are provided by a control key on keyboards where a control key
is available. Depending on the terminal type, the control key provides either a
Control Shift or Control Mode function. The Control Shift function allows you to
select multiple functions while the control key (CTRL) is pressed. The Control
Mode function allows you to enter only one control sequence. Both Control Shift
and Control Mode are indicated by a left-facing arrow displayed in the OIA.
On all keyboards, using the extension mode key or the Extended Select key
followed by the control key invokes the Control Mode on/off function. See
Figure 1-2 on page 1-8 through Figure 1-4 on page 1-9 for the location of these
keys.
COMPOSE Key
The VT220 terminal has a COMPOSE key which allows your terminal working in
Multinational or National Character Set mode to generate ASCII codes for
characters not engraved on its keyboard. These compose sequences are accessed
on 3270 keyboards by using Extended Graphics mode. Tables 2-6 through 2-8 show
you the characters which you can generate in each language.
VT220 National Language Support
You can generate characters by using the following character sets:
• National Replacement Character Set (NRC)
•
Multinational Character Set (MCS).
Note: For the terminal to display a wider range of 3270 characters, the terminal
must be set up with the MCS character set.
DEC National Replacement Character (NCR) Set Mapping
You can generate characters not engraved on the 3270 keyboard by entering
Extended Graphics mode and using the National Replacement Character (NRC)
Set. Refer to the Extended Graphics keyboard layouts in Appendix A, "Terminal
Keyboard Maps."
You can generate all the characters defined in the DEC National Replacement
Character (NRC) Sets except for five characters in Netherlands (see Table 2-6 on
page 2-13).
The characters indicated as "Not mapped" in the following figure cannot be
displayed on the 3270 screen and cannot be generated from 3270 keyboards. If
they are received from the host ASCII application, they appear as blanks on the
3270 screen.
2-12 3174Establishment ControllerTerminal User's Reference for Expanded Functions

IBM 3174 Specifications

General

Brand	IBM
Model	3174
Category	Controller
Language	English