RS232


 
9 PIN D-SUB MALE connector (computer side)


 
25 PIN D-SUB MALE connector

Pin DE9Pin DB25SignalIn/OutDescription
18DCDInData Carrier Detect
23RXDInReceive Data
32TXDOutTransmit Data
420DTROutData Terminal Ready
57GND-Ground
66DSRInData Set Ready
74RTSOutRequest To Send
85CTSInClear To Send
922-RIInRing Indicator
ShellProtective Ground

(*) Pinout is at DTE (Computer) side


Null modem pin mapping:

Connector 1Connector 2
TxDRxD
RxDTxD
RTSCTS
CTSRTS
GNDGND
DSRDTR
DCD
DTRDSR
DCD


RS232 on RJ45 (EIA-561)


8 pin RJ45 male connector (Plug)

RJ45 Pin N.NameDB9 Cross ConnectDescription
1DSR/RI6,9Data Set Ready/Ring Indicator
2DCD1Data Carrier Detect
3DTR4Data Terminal Ready
4GND5Ground
5RD2Receive Data
6TD3Transmit Data
7CTS8Clear to Send
8RTS7Request to Send