Systech Corporation NDS/5000, Руководство по оборудованию

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Connecting Devices to the NDS 18
RS-422/485 Operation
Unlike RS-232, the RS-485 and RS-422 specifications do not have a standard set of pinouts.
In general, whenever you use RS-422/485 devices you will need to make custom cables. The
NDS DB-9 pinouts for RS-422 /RS-485 mode are shown in Table 2-14. The RJ-45 pinouts are
shown in Table 2-15.
Pin
# Name Direction
1 Not used
2 RXB/RX+ Input
3 TXB/TX+ Output
4 Not used
5 GND
6 Not used
7 TXA/TX- Output
8 RXA/RX- Input
9 Not used
Table 2-14: DB-9 Pinouts for RS-422 and RS-485
Pin # Name Direction
1 Not used
2 TXA/TX- Output
3 GND
4 TXB/TX+ Output
5 RXB/RX+ Input
6 GND
7 RXA/RX- Input
8 Not used
Table 2-15: RJ-45 Pinouts for RS-422 and RS-485
RS-485 2-wire mode uses the same pinouts, but the receive and transmit pairs should be
externally shorted together in the connector (TXA shorted to RXA and TXB shorted to RXB).
Note that some RS-422 and RS-485 devices refer to the differential pair of signals that make
up the transmit and receive lines as “-” and “+“ instead of the standard “A” and “B”. In