19
Serial Port Interface
EIA-232D 25 Pin Serial Port Interface
Pin
ITU-TSS
Number
Signal
Name
1
101
2
103
3
104
4
105
5
106
6
107
7
102
8
109
15
114
17
115
18
141
20
108/2
108/1
158
EIA
Signal/Pin
Signal
Description
Name
AA
Protective Ground
(GND).
BA
Transmitted
Data(TXD).
BB
Received
Data(RXD).
CA
Request To Send
(RTS).
CB
Clear To Send
(CTS).
CC
Data Set Ready
(DSR).
AB
Signal Ground
(GND).
CF
Data Carrier
Detected (DCD).
DB
Transmit Clock
Signal (source:
DCE).
DD
Synchronous
Receive Clock.
Local Analog
Loopback Test.
CD
Data Terminal
Ready (DTR).
Connect DCE to
Signal
Direction
DTE -DCE