I had to by an MGL specific conector to allow mt Trig 22 Transponder to interface with the MGL IEFIS Lite. This thing was $90. Way to expensive!
If you choose a Trig 22 Transponder you can either use the panel mount remote head that come with it or you can use the above device to have the transponder controlled by the IEFIS. But not both.
Time was wasted by MGL initially sending me one which was not wired for CAN connecting. They made it good but it was a waste of presious time.