ACC Programmer's Reference Guide

Chapter 3 71
ZCOM Tables and Data Structures
Physical Terminal Tables
PTTXLB - Pointer to next PTT on low priority list linkage
AsforPTTXLAabove,exceptthatthelinkagepertainstothelow
priority transmit queue.
PTTXQB - Low priority transmit buffer queue
The low priority queue is operated in a similar manner to the high
priority queue. Data on this queue is processed only after all express and
high priority data has been processed. Note that requests on this queue
are subject to the unacknowledged and port transmit limits.
PTTXQC - Unacknowledged transmit buffer queue
This queue contains the buffers from PTTXQA/B after they have been
transferred to the interface card, and until they have been acknowledged
as sent (or aborted) by the Mux interface card.
PENDG_TXREQ - Next request of $DATA in unack’d transmit queue
This field is used internally by the ZCOM subsystem.
PTPZLK - ZLU of next PTT on this port
Contains the ZLU number of the next terminal which is on the same
Mux interface and port as this terminal. These ZLU numbers form a
circular list of termin als on the same port. Field PTLIST for ms the same
circular list, but contains the physical terminal table memory address.
PTDRST -Terminalstatus
The terminal status is maintained by the driver in this field. The status
change requests from application programs are updated in this field
after they are successfully passed to the interface card. The driver uses
this value to reset the terminal status on the Mux interface after a
powerfail or reset.
The content of this field is as follows:
Figure 3-4 Terminal Status Field PTDRST
15 10987654321011121314
EN AC
IN -
EN -
Terminal has been initialized (ZCOM_PTDRST_INT)
Terminal is enabled (ZCOM_PTDRST_ENB)
AC -
UP
Terminal is active (ZCOM_PTDRST_ACT)
AV - Terminal is available for use
AV