ACC Programmer's Reference Guide

62 Chapter3
ZCOM Tables and Data Structures
Logical Terminal Tables
LTZLU - Terminal ZLU number
This is the ZLU number of the owning terminal.
LTZCS -OwningZLUchecksum
This is the ZLU checksum of the owning terminal.
LTMUX - Mux interface number for this terminal
This is the M ux interface number that this terminal is configured on.
LTPORT- Port number within the Mux card
This is a one byte field that indicates which port this terminal is
attached to within the Mux card.
LTTERM - Terminal number within port
This is a one byte field that indicates which terminal within a port this
terminal is configured on. This field has been replaced by the ltmxtm
field. This field continues to be valid for 2/8-channel MUX cards for
backwards compatibility reasons.
LTPTERM - Pointer to the physical terminal table (zptt_type *)
It contains the memory address of the related physical t erminal t able.
This field is used as a linkage to find physical terminal information.
LTGZLK - ZLU of next terminal in group
Contains the circular linkage of ZLUs linked to the same physical
terminal. The linkage is to allow de-multiplexing of inbound messages.
For a normal 1:1 t erminal, the entry will contain its own ZLU number.
Note that there is no checksum associated with this ZLU.
LTDEVC -Terminaldevicetype
Unique identification of the actual terminal connected to the system.
Two different terminals can have the same screen format and physical
protocol, but the device type may not necessarily be the same; it relates
to the symbolic device type specified in the TTGEN configuration file.
LTTYPE - Logical terminal type
The logical terminal type is used to describe the message format
expected from the terminal. For screen-type terminals this will identify
the terminal as belonging to a class of terminals with the same screen
formatting attributes and message delimiters (e.g ., IBM.3278 or
NCR.501).