Appendix d serial port interface – ZyXEL Communications omni.net Plus User Manual
Page 183

Technical Reference for ZyXEL omni.net series
D-1
Appendix D
Serial Port Interface
EIA-232D 25 Pin Serial Port Interface
Pin #
Description
ITU-TSS
Signal
Name
EIA
Signal
Name
Signal Description
Signal Direction
DTE - DCE
1 GND
101
AA Protective
Ground
+*
2 TXD
103
BA
Transmitted
Data
*
3 RXD
104
BB
Received
Data
+
4
RTS
105
CA
Request To Send
*
5
CTS
106
CB
Clear To Send
+
6
DSR
107
CC
Data Set Ready
+
7 GND
102
AB Signal
Ground
+*
8
DCD
109
CF
Data Carrier Detected
+
15
Clock Source:
DCE
114
DB
Transmit Clock Signal
+
17
Sync RX Clock
115
DD
Synchronous Receive Clock.
+
18
LA/LBK
141
Local Analog Loopback Test.
*
20 DTR
108/2
108/1
CD
Data Terminal Ready.
Connect DCE to line.
*
21
RD/LBK
140
Remote Digital Loop Test.
*
22 RI 125
CE
Ring
Indicator
+