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

Four RS-422 separate data pairs are provided for transmit (TX) and receive (RX). Additionally, there is a 120 Ohm terminating resistor provided for each data pair for applications that require an EOL termination. The termination is optional and is accessible by connecting the terminating pin for each data transport pair.

To enable termination for the transmit pair, connect the terminating resistor pin (TX Terminator) to the positive data transmit (TX+) pin.

To enable termination for the receive pair, connect the terminating resistor pin (RX Terminator) to the positive data receive (RX+) 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.

Note: Transmit (TX) and Receive (RX) are from the point of view of the NioNode. Connect them to the opposite port of the remote unit.

Pin

Function

Pin

Function

1

TX Data +

6

TX 120 ohm terminating resistor

2

TX Data -

7

RX Data +

3

RX 120 ohm terminating resistor

8

RX Data -

4

+12 VDC (0.5A)

9

Reserved (no connection)

5

Ground

 

 

See also

RS-232 serial port

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

Serial control protocols