TN3270e Server Manual

TN3270e Server Manual—422923-003
5-1
5 CRT Communication Protocol
This section is divided into the following parts:

CRT Mode describes the format of Telnet 3270 data in CRT mode.

SNAX/XF Mode on page 5-3 describes the applicable file system procedures for
running the TN3270e server in SNAX/XF mode.
CRT Mode
The TN3270e server windows in CRT mode use data buffers passed from an
application which contain standard 3270 buffer orders and text. The TN3270e server
does not examine the screen orders. Communications-related characters are added or
stripped depending on whether the data is inbound or outbound.
You can configure the TN3270e server to run in CRT or ITI mode with a SETMODE 8
call. See Section 6, ITI Communication Protocol for more information about running the
TN3270e server in ITI mode.
Message Format for Outbound Data
For outbound data, as shown in Figure 5-1, the buffer should contain only the textual
part of a screen, from the command character (CMD) through the end of the screen
orders and the text. The TN3270e server adds an end-of-record indicator to the end of
the buffer.
Figure 5-1. CRT Protocol Message Format for Outbound Data
VST006.vsd
Telnet
Specific
Application
E
O
R
I
A
C
3270 Screen Orders
W
C
C
C
M
D
3270
Telnet (TCP/IP)