Great information!!! I had post asking for just this info. We tried a Futaba PCM TX in both PCM and PPM modes and got nothing from the RX as you sugest. We only tried a Futaba PPM RX and got nothing from that. This was all 72 MHZ. One good thing was the PCM didn't allow any interference from the another TX with the same channel.
Also, the Zhen Hua site decribes the Dip's as 1-4 servo reversing, 5 Simulator mode, and 6 mixes channels 3 and 4.
I have a 22D heli with shaft drive tail and FP. This unit also has a mixer between the main motor and rudder control, do I realy need that? I was thinking of swapping out everything and getting a 4 channel with a gyro and speed controller.

Thanks,
Racer...