RAD Data comm ASM-20 operation manual Appendix C IR-X.21B Interface Module

Appendix C

IR-X.21B Interface Module

C.1 General

This appendix:

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Provides a general description of the IR-X.21B interface module

Describes the IR-X.21B connectors and pin assignments

Describes the IR-X.21B interface module

Describes the EXT mode for the IR-X.21B

Describes the INT/RCV mode for the IR-X.21B.

C.2 General Description

The IR-X.21B is an interface module for RAD modems, converting X.21 signals to TTL levels. The converted data is sent over the modem link, using the modem modulation technique, and is converted back at the other end into X.21 signals, or into any other digital interface signal.

Figure C-1shows a typical application of the ASM-20 standalone modem with the IR-X.21B interface module.

X.21 Network

R AD	Line	X .21
	R AD

ASM Rem ote Location

DTE

Figure C-1 Typical ASM-20 X.21 Application

General Description C-1