are you sure it's 25 pin to 10 pin? and not 25 pin to 9 pin? like this one...
If I remember rightly, these leads used to be used for printers, scanners, tape drives etc... the 9 pin is connected via a com 1 or 2 port, old mice usually used com 1.
The 25 pin male parallel usually connects to the appliance (scanner etc.). or it could by similar to a laplink cable for data transfer pc to pc.