Table B.3: RS-422/485 Pinouts
Name | Description | Direction | DB9M |
| | | Pin |
| | | |
RD(A) − | Receive Data A | Input | 1 |
TD(B) + | Transmit Data B | Output | 2 |
TD(A) − | Transmit Data A | Output | 3 |
GND | Signal Ground | ------ | 5 |
RD(B) + | Receive Data B | Input | 9 |
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.
See Chapter 2 for example connections.
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 the B&B Electronics RS-422/485 Application Note (available on our website).
B-2 | Appendix B | Documentation Number 3PCIO1-0903 Manual |
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