Black Box LES404A, LES402A B.2 1-Port Serial Server Terminal Block Pinout in RS-422 Mode, Page

Appendix B: RS-422/485 Connections

B.2 1-Port Serial Server Terminal Block Pinout in RS-422 Mode

Figure B-2. Terminal block connector.

Table B-2. 1-Port serial terminal block pinout

in RS-422 mode.

Signal Name	RS-422	RS-232	Terminal
Signal Ground	—	GND	1
Transmit Data (-)	TXD(-)	Out	2
Transmit Data (+)	TXD(+)	Out	3
Receive Data (+)	RXD(+)	In	4
Receive Data (-)	RXD(-)	In	5

In the RS-422 mode, TXD lines are outputs and RXD lines are inputs. Connect the Serial Server TXDB(+) line to the RXDB(+) line of the serial device, and the Serial Server TXDA(-) to the RXDA(-) of the serial device.

If flow control is set for RTS/CTS, connect the Serial Server RTSB(+) to CTSB(+) of the serial device and the Serial Server RTSA(-) line to the CTSA(-) of the serial device. Connect from the Serial Server CTSB(+) line to the RTSB(+) of the serial device and from the Serial Server CTSA(-) line to the RTSB(+) line of the serial device.

If connecting to receive-only RS-422 devices, connect from the Serial Server TXDB(+) and TXDA(-) lines to the receive pairs on all serial devices.

Ground is signal ground and provides a common mode reference for the RS-422 receiver and transmitters.

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