1 x TJ-101 (U-174 socket)
1 x PJO68 (.206" Mic Jack)
http://www.davidclark.com/HeadsetPgs/h10-56.htm
I dunno what the "HX" means ...
Agree with you on the price of adapters - and they're usually too long!
If you're going to have an avionics guy look the thing over, then he (or she) might well have these plugs handy. It's be a shame to run all over trying to find these and wind up with the wrong ones - it's easy to do, even if they seem to fit the headset (voice of experience!)