RS-422/485 serial port in RS-485 mode

For RS-485 applications the serial port is configured for half-duplex operation. A single data pair is provided for transmit (Data+) and receive (Data-).

Additionally, there is a 120 Ohm terminating resistor provided for applications that require an EOL termination. The termination is optional and is accessible by connecting the terminating pin (TX Terminator) to the positive data (Data+) pin.

Power (+12VDC) is provided on pin 4 and is referenced to ground, pin 5. The power pin is protected by a self-resetting fuse and is limited to 0.5A, max.

Pin

Function

Pin

Function

1

Data +

6

TX 120 ohm terminating resistor

2

Data -

7

Not used

3

Not used

8

Not used

4

+12 VDC (0.5A)

9

Reserved (no connection)

5

Ground

 

 

See also

RS-232 serial port

RS-422/485 serial port in RS-422 mode

Serial control protocols