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Using an RS-232C/RS-422A Adapter Appendix C
Pin Arrangement
The Adapter has a terminal block for an RS-422A/485 interface connection and a connector for an RS-232C
interface connection.
The pin arrangements for the RS-422A/485 terminal block and the RS-232C connector are as follows.
RS-422A/485 Terminal Block
* The CSB and CSA signals are for specialized applications.
RS-232C Connector
* The hood is connected to the functional ground terminal of the RS-422A terminal block.
Terminal
block pin
No.
Signal name Abbreviation Signal direction
(Adapter ⇔ RS-422 device)
8 Request to send (−)CSA→
7 Request to send (+) CSB →
6 Receive data (−)RDA←
5 Receive data (+) RDB ←
4 Send data (−)SDA→
3 Send data (+) SDB →
2 Signal ground SG (GND) –
1 Functional ground –
Connector
pin No.
Signal name Abbreviation Signal direction
(Adapter ⇔ RS-232C device)
1 Not used – –
2 Send data SD ←
3 Receive data RD →
4 Request to send
(shorted to CS internally)
RS ←
5 Clear to send
(shorted to RS internally)
CS →
6 +5 V (150 mA) input for Adapter +5 V →
7 Data set ready
(shorted to ER internally)
DR →
8 Data terminal ready
(shorted to DR internally)
ER ←
9 Signal ground SG –
7
5
3
1
8
6
4
2
6
7
8
9
1
2
3
4
5