ZCOM Tables and Data Structures

Physical Terminal Tables

PTZPCTL_RCVR - ZCOM address of primary control receiver

This is the node number, ZLU, and checksum used as the destination address for any control input messages received for this terminal. This field is set by a zset_rcvr mode 3 call. The control input messages are distinguished by the protocol modules on the MUX, by setting bit 1 of the input message tag byte.

PTZSHRCVRS - Pointer to a linked list of shared receivers

This field contains a pointer to a linked list of programs that wish to receive normal messages and unsolicited status messages from this physical terminal. Each entry in the linked list contains the node number, ZLU, and checksum of the application which will be used as the destination address for normal messages and unsolicited status messages received from this physical terminal. This field is set by the zset_rcvr call (mode 0 or mode 1 if multiplexed terminal). If there are no shared receivers, this field will contain a zero. When a data or status message arrives, it will be delivered to each application in the linked list (as well any primary receiver).

PTZSHCTLRCVRS - Pointer to a linked list of shared control receivers

This field contains a pointer to a linked list of programs that wish to receive control messages from this physical terminal. Each entry in the linked list contains the node number, ZLU, and checksum used as the destination address for any control input messages received for this terminal. This field is set by a zset_rcvr mode 3 call. The control input messages are distinguished by the protocol modules on the MUX, by setting bit 1 of the input message tag byte. If there are no shared control receivers, this field will contain a zero. When a control message arrives, it will be delivered to each application in the linked list (as well an any primary control receiver).

PTLIST - Pointer to next PTT on the same port

Contains a pointer to the physical terminal table of the next terminal on the same Mux interface card and port number as the current terminal. These pointers form a circular list of terminals on the same port. Field PTPZLK forms the same circular list, but contains the ZLU number.

Chapter 3

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