Goldwing,
Neither simple parallel, nor simple serial cable will do.

Only two types of cables will work under XP:

1) PIC-based serial cable (go to FMS Forums, they have a group for PIC-interfaces). Pro: 8 proportional cahnnels; con: the cable only works with FMS and isn't compatible with anything else.

2) TX-to-Joystick interfaces (either gameport- or USB-joysticks). Pro: works with any Windows application (FMS, RealFlight, etc.); con: only provides 4 proportional and 4 discrete channels.

Hope this helps,
Boris