Joystick Ports as Duplex Data Port

[zachriggle]

Is it possible to not only transmit data through the joystick port, but to also receive it? I understand that this may not (most likely will not, I think I remember reading something along those lines) be allowed during the competition, but it would help immensely for debugging purposes.

My reason for asking is that I want a diagnostic system that will work when the FRC isn't hooked up directly via parallel port, and can't afford (the Team can't) to shell out $100+ on a wireless radio set for the RS232 port.