Not so ...
I put my Airtronics Tx into PPM/FM transmission, no problem for the Futaba PCM reciever of the other flyer on the same frequency. It doesn't hear it, even though we are on the same frequency.
It's just that my PCM receiver will react to the other manufactuerer's PCM Tx signal, and vice-versa, by going into "lock out". Not unexpected of course. As I said, not good news ... so much for manufacturer specific proprietary encoding PCM transmission being of a practical benefit to the flyer.
That is the point I am making.
I'll go back to my coma now ...
fiery