DB9 RS232 pinout

Pin Signal In/Out Description
1 DCD In Data Carrier Detect
2 RxD In Receive Data
3 TxD Out Transmit Data
4 DTR Out Data Terminal Ready
5 GND - Ground
6 DSR In Data Set Ready
7 RTS Out Request To Send
8 CTS In Clear To Send
9 RI In Ring Indicator
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