ACC X.25 Protocol User's Guide

30 Chapter3
ZX25D X.25 Protocol Driver
Configuration
statement. Note that this definition is not needed if the call user data
will always be supplied as a parameter in the zx25...() routines or if no
call user data is being sent.
This definition, if required, is as follows:
logical-data app X25UDT 0 20
The app number is the application number parameter from the virtual
circuit terminal definition statement. If multiple terminals with
different application numbers require call user data, then the X25UDT
should be allocated globally by specifying application zero (0).
The storage could be allocated at any valid offset within the logical
terminal table extension area. In the example it is allocated at the first
available byte (0). The minimum size of 20 bytes should be used (16 bytes
for a fixed-size ca ll user data b uffer, plus two bytes in t he front of the
buffer for a count of the actual number of bytes used i n the call user data
buffer, plus two bytes at the end for data structure alignment purposes).
If more than 16 bytes of call user data is needed, you must supply it as a
parameter in the zx25...() ro utines. You could also define X25UDT to be
bigger than 20 bytes. That would allow you to store Ldata entries after
the Udata in this same X25UDT Logical-Data area.
Interface Definitions
A M ux definition line appears in t he TTGEN configuration file for each
multiplexer that w ill have X.25-connected terminals configured on it.
The firmware file that is used for ACC cards using X.25 is different from
the firmware files that are used for other protocols. It is possible,
however, to use other protocols with X.25 on a single ACC card, provided
the firmware file has been customized to include those other protocols.
Refer to the ACC Installation and Configuration Guide for more
information on creating firmware files for multiple protocols.
Several sample interface definitions are as follows:
Z7200A 0 0:4 /opt/acc/z7200a/x25.zabs /* 8-port card */
Z7350A 0 2:16 /opt/acc/z7350a/x25.zabs /* 2-port card */
Z7300A 2 0:8 /opt/acc/z7300a/x25.zabs /* 4-port E1/T1 */
The “.zabs”firmwarefilemusthaveatleasttheX.25andLAP-Bprotocol
modules loaded i nto it, and it may contain other protocol modules. Refer
to the TTGEN section of the ACC Utilities Reference Guide for more