ACC Programmer's Reference Guide

Chapter 2 33
ZCOM Message Handling
Multiplexing
Figure 2-4 Inbound Multoplexing
Thus, to process an inbound message with multiplexing:
• zread (themessagetypewillbetype1,ZCOM_MSTYPE_MSLT-a
message from a terminal ZLU).
• The source ZLU is obtained from PTZLU. PTZLU gives the ZLU of
one of the ZLUs in a multiplexed group.
• Decode the protocol header to extract the logical terminal address.
Use the ltfind routine to scan the multiplexed group to find a match of
the logical terminal address with LTADDR.
• Build a ZCOM message header where the source ZLU is the ZLU
found by ltfind, and the destination ZLU is taken from LTZRVR of the
logicalterminalable.
•Usezsend (with bit ZCOM_ZSEND_MHD set) to send the message
and the ZCOM header t o LTZRVR.
Logical
Terminal
TZLU
APPLICATION
LTZRVR
PZLU
Physical
Te r m in a l
PTZLU
PTZRVR=PZLU