Serial port, Chapter 2. getting started, Rs232 – Solvline Eddy DK Ver 2.20 User Manual
Page 13: Rs422 full duplex, Rs485 half duplex

Chapter
2. Getting Started
6
RXD-
Receive Data -
LED
Description
Left Green
Upon 100Base-TX link, it lights. When the data is sent or
received, it blinks.
Right Yellow
Upon 10Base-T link, it lights. When the data is sent or received, it
blinks.
2.3.3.2.
Serial Port
Figure 2-1 Serial port pin description
RS232
Pin
Signal
Description
1
DCD
Data Carrier Detection (Input)
2
RXD
Receive Data (Input)
3 TXD
Transmit
Data
(Output)
4 DTR
Data
Terminal
Ready
(Output)
5 GND
Ground
6
DSR
Data Set Ready (input)
7
RTS
Request to Send (Output)
8
CTS
Clear to Send (Input)
9
RI
Ring Indicator (Input)
RS422 Full Duplex
Pin
Signal
Description
2
RXD+
Receive differential data positive (Input)
3 TXD+
Transmit
differential data positive (Output)
6
RXD-
Receive differential data negative (input)
7 TXD-
Transmit
differential data negative (Output)
RS485 Half Duplex
Pin
Signal
Description
3
TRX+
Transmit/Receive differential data positive
7
TRX-
Transmit/Receive differential data negative
2-5