Chuck
Here's the answer I got from milehighwings.

Both, game port and USB, versions will work with your TX and computers (assuming that your PCs have game ports).
The main difference between our USB and joystick interfaces is in the number of proportional channels: USB gives up to 7 proportional channels, while game port interface is limited to only 4 proportional and up to 4 discrete channels (which is the limitation of the game port itself).

Tom Albers