DS4800 REFERENCE MANUAL
62
5
5.2.2 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 connector pinout follows:
25-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
DS4800
TX+
2
TX-
4
RX+
3
RX485
RX-
5
TX485
7
GND
GND
USER INTERFACE
+
-
+
-
Chassis
1
Figure 52 - RS485 Full-duplex Connections
NOTE
For applications that do not use RX signals, do not leave these lines floating
but connect them to GND as shown below.
DS4800
TX+
2
TX-
4
RX+
3
RX485
RX-
5
7
GND
GND
USER INTERFACE
+
-
Chassis
1
Figure 53 - RS485 Full-duplex Connections using Only TX Signals
