IBM 3174 Reference Guide

Differences
Introduction
This chapter provides information about using a 3270 terminal to communicate with
ASCII hosts through an IBM 3174 Establishment Controller. The 3174 allows you to
do this by making the data entered at your 3270 terminal look as if it were entered
from one of these ASCII terminals:
• IBM 3101
• DECVT100
• DECVT220
• Data General Dasher D210.
Also described are:
• Using 3270 printers as ASCII printers
• IBM Personal Computers in 3270 Emulation Mode.
When you use a 3270 terminal as an ASCII terminal, you see some differences in
how your terminal operates.
Differences When Using Your 3270 Terminai as an ASCIi Terminal
As a 3270 terminal user accustomed to the way keystrokes are handled, you may
see a difference in keying response time when you are connected to an ASCII host,
especially when you are using dial lines. That is, as you type characters on your
keyboard you may experience a deiay from the time you press the key to when the
character appears on your screen. Following are some differences you may see if
your terminal is communicating with an ASCII host that uses IBM 3101, DEC VT100,
DEC \/T200, or the DG D210 data stream.
Scrolling
You can see a difference in screen scrolling. IBM 3270 terminals cannot roll the
screen up one line at a time to make room for new data, so the full screen is
written from the controller instead. If the controller is used heavily, less frequent
and partial updates are used so that performance is not degraded for other users.
You can stop the scrolling by doing the following:
Data Stream Action
VT100 Use the key shown in your keyboard map for the NO-SCROLL key
(Backtab) to stop. Use the NO-SCROLL key (Backtab) again to
resume.
VT200 Use the key shown in your keyboard map for the HOLD-SCREEN
key (Backtab) to stop. Use the HOLD-SCREEN (Backtab) key again
to resume.
3101 Use CTRL-S for XOFF to stop. Use CTRL-Q for XON to resume.
Note: Not all hosts observe this protocol; it is
application-dependent.
2-2 3174 Establishment Controller Terminal User's Reference for Expanded Functions

IBM 3174 Specifications

General

Brand	IBM
Model	3174
Category	Controller
Language	English