RAD Data comm ASM-20 operation manual Interface module $87,21 25&21,18, Pin Function

Appendix C. IR- X.21B Interface Module ASM-20Installation and Operation Manual

C.3	IR-X.21B Connectors
Figure C- shows the rear panel of a standalone ASM-20 with the IR-X.21B
interface module.
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	7<3($1'5$7,1*2))86(￿
		X2 1	Line Connector

Figure C-2 ASM-20 Rear Panel with X.21 Connector

The ASM-20 modem rack version requires an additional adapter to connect between the DB-15 connector of the X.21 equipment to the DB-25 connector of the ASM-MN-214 modem rack. For this purpose, an optional DB-15 attachment CIA/X.21 can be ordered separately from RAD. The attachment connects to the ASM-MN-214 rear panel as shown in Figure 5-3for the CIA/V.35 attachment.

Pin Assignment Table C-1shows the X.21 DB-15 pin assignment.

Table C-1 IR-X.21B DB-15 (RS-422) Connector Pin Assignment

Pin	ID	Function
1	Shield	Chassis connection
2	A	Transmit signal A
3	A	Control A
4	A	Receive A
5	A	Indication A
6	A	Signal timing A
7	A	External Timing
8	GND	Common
9	B	Transmit B
10	B	Control B
11	B	Receive B
12	B	Indication B
13	B	Signal Timing B
14	B	External Timing

C-2 IR-X.21B Interface Module