Serial Cable Pinouts

This mapping is the same for male and female connectors.

There are two standards for IDC-to-DB9, one is the standard straight-through method, mapping pin n on the IDC to pin n on the DB-9. The other is “Intel” format, which does a completely daft mapping. This is explained here.

You can detect this by measuring the voltage between pin 5 and pins 2 and 3, one of which should be positive and one negative. In the Intel configuration, pin 5 isn't ground, and the voltage on pins 2 and 3 will have the same sign.