Eyrie, I owe you an apology! Checked the Enigma site and I am gobsmacked...the company had a solution in the works over ten years ago. All they needed was the gps engine to get the proper TSO...which it did over six years ago...and now this! If enigma reads this...I reckon you guys have dropped the ball big time. A blind mounted basic encoder to feed the data to a mode S was all that was required.