Instruction manual
MATRIX 200™ REFERENCE MANUAL 
5 
5.3.2  RS485 Full-Duplex Interface 
The RS485 full-duplex (5 wires + shield) interface is used for non-polled communication 
protocols in point-to-point connections over longer distances (max 1200 m / 3940 ft) than 
those acceptable for RS232 communications or in electrically noisy environments. 
The following pins of the 25-pin connector are used for RS485 full-duplex communication: 
Pin Name  Function 
2  TX+  RS485 Transmit Data (+) 
3  RX+  RS485 Receive Data (+) 
4  TX-  RS485 Transmit Data (-) 
5  RX-  RS485 Receive Data (-) 
7 GND  Ground 
Matrix 200™ 
TX+ 
2
TX- 
4
RX+ 3
RX485
RX- 
5
TX485
7
GND 
GND 
USER INTERFACE
+
-
+
-
Chassis
1 
Figure 64 - RS485 Full-duplex Connections 
NOTE 
For applications that do not use RX485 signals, do not leave these lines 
floating but connect them to GND as shown below. 
Matrix 200™ 
TX+ 
2
TX- 
4
RX+ 3
RX485
RX- 
5
7
GND 
GND 
USER INTERFACE
+
-
Chassis
1 
Figure 65 - RS485 Full-duplex Connections using Only TX Signals 
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