Black Box LES402A Appendix B RS-422/485 Connections, Appendix B. RS-422/485 Connections, Page

Appendix B: RS-422/485 Connections

Appendix B. RS-422/485 Connections

B.1 2- and 4-Port Serial Server DB9 Pinout in RS-422 Mode

Figure B-1. DB9 connector.

Table B-1. RS-422 connections in a DB9

connector.

RS-232 Signal Name	Direction	RS-422	DB9 M Pin
Receive Data A (-)	In	RXDA (-)	1
Receive Data B (+)	In	RXDB (+)	2
Transmit Data B (+)	Out	TXDB (+)	3
Transmit Data A (-)	Out	TXDA (-)	4
Signal Ground	—	GND	5
Clear To Send A (-)	In	CTSA (-)	6
Clear To Send B (+)	In	CTSB (+)	7
Request To Send B (+)	Out	RTSB (+)	8
Request To Send A (-)	Out	RTSA (-)	9

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