HMS Networks Ewon Netbiter EC300 Series User Manual page 10

Installation
2.3.6 RS-485 Serial Interface (3-pin)
Fig. 8 RS-485 connector
The RS-485 interface can be used for multiple Modbus RTU devices.
RS-485 connector pin layout
Pin
A
B
COM
2.3.7 RS-232 Serial Interface (3-pin)
Fig. 9 RS-232 connector
The RS-232 interface can be used for a single Modbus RTU device.
RS-232 connector pin layout
Pin
Rx
Tx
GND
Netbiter EC300 Series User Manual
Function
RS-485 A line
RS-485 B line
RS-485 common
Function
Receive (input)
Transmit (output)
Signal ground
8 (28)
SCM-1202-012 2.3 en-US