I have built the Parallel, Joystick and PIC interfaces for My RD6000 radio.
I refer the PIC from Ken in England. (but they all work).
If you are running win95 or 98 the parallel interface will work. If not you need the PIC, Joystick or maybe the Audio interface.
OBTW Ken's PIC interface is only $15.00 USD for the kit and $20.00 USD for the built unit SHIPPED. (10.44 - 13.92 GBP, If my converter works right

)
John