This adapter will enable you to connect a 25 pin male serial cable to a 9 pin female serial connector on your computer.

9 pin female connector

9 pin D-Sub Female

25 pin male connector

25 pin D-Sub Male

9-Pin to 25-Pin Adapter Pinout

Signal 9-Pin 25-Pin
Carrier Detect 1 8
Receive Data 2 3
Transmit Data 3 2
Data Terminal Ready 4 20
System Ground 5 7
Data Set Ready 6 6
Request to Send 7 4
Clear to Send 8 5
Ring Indicator 9 22

This data was contributed by the team at The Hardware Book.