RS232 Serial Devices

25 PIN 9 PIN DESCRIPTION
1   Shield
2 3 Transmit
3 2 Receive
4 7 Request To Send (RTS)
5 8 Clear To Send (CTS)
6 6 Data Set Ready (DSR)
7 5 Signal Ground
8 1 Data Carrier Detect (DCD)
20 4 Data Terminal Ready (DTR)
22 9 Ring Indicator

To bypass hardware hand-shaking, tie pins 4 and 5 together and pins 6, 8, and 20 together.