For W2000 about the only useful interface circuit is the one that comes with FMS in the Doc\Interface folder. You need to be able to program a PIC microcontroller if you want to build it yourself.

Otherwise you can buy one but make sure you buy either a PIC serial i/f or a joystick i/f. Try Ken Hewitt at http://www.rc-electronics.co.uk/ for either of those. The cheap parallel/serial ones do not work with W2000.

Hitec and Futaba trainer sockets are compatible provided the Futaba has the current 6-pin DIN socket not the very old 5-pin version.

Steve