DB9 pinout and signals for the PC RS232 connector (serial and RS232 ports)

DB9 pin D-SUB male DB9 pin D-SUB male

Pin Name Direction Description
1 CD Carrier Detect
2 RXD Receive Data
3 TXD Transmit Data
4 DTR Data Terminal Ready
5 GND System Ground
6 DSR Data Set Ready
7 RTS Request to Send
8 CTS Clear to Send
9 RI Ring Indicator
Note: Direction is DTE (Computer) relative DCE (Modem).
Our software allows you monitor, log, debug and test any your RS232 or COM ports.

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