TCT—terminal control table

All VTAM® connected terminals, intersystem communication links, and multiregion operation links must be defined using resource definition online (RDO). See Devices supported for details of VTAM terminals supported by RDO.

A CICS® system can communicate with terminals, sequential devices, logical units, and other systems. The TCT defines each of the devices in the configuration. Each TCT entry defines the optional and variable features of the device to CICS, and specifies the optional and variable features of CICS to be used.

CICS uses a telecommunication access method to communicate with terminals. This may be VTAM or Start of change(for sequential devices) BSAMEnd of change; you may use one or both of these in your system.

Attention: Start of changeCICS TS for z/OS®, Version 3.1 does not support:
  • The Basic Telecommunications Access Method (BTAM), in any form.
  • The Telecommunications Access Method (TCAM). That is, you cannot use TCAM to communicate with locally-attached terminals. However, you can define, as remote terminals, terminals attached by TCAM/DBC to a back-level CICS terminal-owning region (TOR). TCAM/ACB is not supported at all.
End of change

A terminal can be a telecommunication device; for example, an IBM® 3279 Color Display Station, or a subsystem such as an IBM 4700 Finance Communication System. Terminals can be local (channel-attached) or remote (link-attached).

You can use a sequential device to simulate a CICS terminal. You can define a card reader or punch, line printer, direct access storage device (disk drive), or magnetic tape drive as a sequential device.

A logical unit (LU) is a port through which a user of an SNA network gains access to the network facilities.

A system can be, for example, another CICS system, an IBM 8815 Scanmaster, an IBM Displaywriter, or an APPC/PC. Intercommunication with CICS systems can be:
  • Between different processors (intersystem communication or ISC), using the LUTYPE 6.1 or LUTYPE 6.2 protocols, or using an intermediate system as an indirect link. (Intercommunication with non-CICS systems also uses ISC.)
  • Within the same processor (multiregion operation or MRO), using interregion communication (IRC). (You can also use LUTYPE 6.2 ISC within the same processor.)
There are three ways in which you can create TCT entries, and install them in the TCT.
  1. By using resource definition online (RDO) to create resource definitions in the CICS system definition (CSD) file. You must use RDO for VTAM-connected terminals (local and remote) and for MRO and ISC links and sessions. See Terminal definition attributes for more information on defining terminals using RDO.For information on migrating your temrinal definitions to the RDO equivalent, see Migrating the TCT to the CSD file.
  2. By using RDO and autoinstall (for VTAM-connected terminals only). See Autoinstalling VTAM terminals for information about autoinstall for terminals.
  3. By coding DFHTCT macros, assembling them, and selecting the resulting TCT by using the TCT operand at system initialization. This way, TCT entries can be installed at system initialization only.
    Start of changeYou must use DFHTCT macros, which are described in this section, to define:
    • Logical units supporting logical device codes (even though they are VTAM devices).
    • Sequential devices attached by BSAM.
    • Remote TCAM terminals.
    End of change