RS-232 serial pinouts
25 pin
1 - Ground
2 - Transmit Data (TD)
3 - Receive Data (RD)
4 - Request to send
5 - Clear To Send (CTS)
6 - Dataset ready
7 - Signal Ground (SG)
8 - Data Carrier Detect (DCD)
20 - Data Terminal Ready (DTR)
22 - Ring Indicator
9 pin
1 - Data Carrier Detect (DCD)
2 - Receive Data (RD)
3 - Transmit Data (TD)
4 - Data Terminal Ready (DTR)
5 - Ground
6 - Data set ready
7 - Request to send
8 - Clear To Send (CTS)
9 - Ring Indicator
