Using Glass TTY Terminals › Overview

Overview

Most maps prepared by using the online or batch compiler and utility can be displayed on a visual-display teletypewriter terminal (glass TTY). Before attempting to map to or from a glass TTY, the user must prepare a device independence table for the given TTY, as described throughout this appendix.

Note: Key names and control codes discussed in this appendix do not apply to all glass TTY terminals. Documentation of a given TTY terminal should be consulted to verify the keys and codes used by that terminal.

Types of Tables

Several different device independence tables can be created at a site, as described as follows:

• A unique device independence table may have to be created for each type of glass TTY terminal available at a site. In other cases, a given device independence table can be used for a group of terminals.
• Different device independence tables can be created for the same type of TTY if, for example, some users need to see different attribute byte symbols on their TTY screens or are accustomed to associating different functions with particular function keys.

At the beginning of a terminal session, the operator loads a specific device independence table by using the DCUF SET SCREEN statement. The RHDCTAPR module uses the specified TTY device independence table during runtime.

Note: For more information about the DCUF SET SCREEN statement, see the CA IDMS System Generation Guide.

Steps

To create a device independence table, the user must perform the following steps:

1. Prepare statements that establish data conversion information for the given TTY.
2. Assemble and link those statements into an RHDCTTBL module and execute the module.

These steps are discussed separately, following information about the TTY environment and the restrictions imposed on mapping by TTY limitations.

Note: Throughout this appendix, both 3270- and 3279-type terminals are referred to as 3270-type terminals.