RAD Data comm ASMi-31 operation manual Table C-1shows the X.21 DB-15 pin assignment

Appendix C. X.21 Interface ModuleASMi-31Installation and Operation Manual

Pin Assignment	Table C-1shows the X.21 DB-15 pin assignment.
	Table C-1		IR-X.21 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
	15			Not connected

C-2 X.21 Connectors

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