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Documentation Number 3PCIOSD1x-3903m Manual Appendix B B-1
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
Appendix B: RS-232 & RS-422/485 Pinouts
Table 1: RS-232 Pinouts
With 2-wire RS-485 mode operation, your connection cable must
jumper TD(A) to RD(A) and TD(B) to RD(B). Connect from TD(A)
and TD(B) to the Data A(−) and Data B(+) wires of your RS-485
network.
Note that the EIA RS-422 Specification labels data lines with an "A"
and "B" designator. Some RS-422 equipment uses a "−" and "+"
designator. In almost all cases, the "A" line is the equivalent of the
"−" line and the "B" line is the equivalent of the "+" line. More
information on RS-422 communications can be found in our free RS-
422/485 Application Note (available on our websites).
Name Description Direction DB25M
Pin
Shield Shield ------ 1
TD Transmit Data Output 2
RD Receive Data Input 3
RTS Request to Send Output 4
CTS Clear to Send Input 5
DSR Data Set Ready Input 6
GND Signal Ground ------ 7
DCD Data Carrier Detect Input 8
DTR Data Terminal Ready Output 20
Table 2: RS-422/485 Pinouts
Name Description Direction DB25M
Pin
Shield Shield ------ 1
TD (A) −
Transmit Data A Output 2
RD (A) −
Receive Data A Input 3
GND Signal Ground ------ 7
TD (B) + Transmit Data B Output 14
RD (B) + Receive Data B Input 16
B-2 Appendix B Documentation Number 3PCIOSD1x-3903m Manual
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445