TLT—terminal list table

A terminal list table (TLT) generated by the DFHTLT macro instruction allows terminal and operator identifications to be grouped logically.

A TLT:

Is mandatory for use by CEST (the supervisor terminal transaction), to define and limit the effective range of the operation. For example:
```
CEST SET TERMINAL(*) SUPRID(CG) OUTSERVICE
```
sets all terminals defined in DFHTLTCG out of service.
May be used by CEST or CEMT (the master terminal transaction) to apply an operation to a predetermined group of terminals. (For a CEST operation, this TLT must define a subset of the TLT specified by SUPRID.) For example, each of the following commands:
```
CEST SET TERMINAL(*) SUPRID(CG) CLASS(EM) INSERVICE
CEMT SET TERMINAL(*) CLASS(EM) INSERVICE
```
sets all terminals defined in DFHTLTEM in service.
May be used singly or in combination with other TLTs to provide predefined destinations for message switching. For example:
```
CMSG ROUTE=PG,'PRODUCTION MEETING AT 11.00 IN
            ROOM 2124',SEND
```
sends a message to all terminals or operators defined in DFHTLTPG.

The same TLT can be used for message switching and for supervisory or master terminal functions. For example, a TLT defining the terminals that are under control of a supervisory terminal could also be used as a destination list for sending messages to those terminals.

For some logical units, logical device code (LDC) mnemonics (that may be associated with each table entry), are used for message switching and are ignored for master and supervisory terminal operations.

In an intercommunication network, all the terminals in a terminal list table must be owned by the system on which the table is used.

The following macros define the TLT entries:

Control section—DFHTLT TYPE=INITIAL
Entries in terminal list table—DFHTLT TYPE=ENTRY
End of terminal list table—DFHTLT TYPE=FINAL (see TYPE=FINAL (end of table))