RE: What does PCM mean on a transmitter?
Go with the PCM radios. The Futaba 9CAP will work in either mode, but the 9CAF only works PPM. It gives you a broader choice of receivers.
By the way, the 9C is a great radio. It is amazing what you can do with mixing and such. The only complaint I have is the speaker for the timer is very weak. I've learned to live with it, and am getting good at dead sticks. Well not really, but I'm getting practice. Guess it's time to get the egg timer back out.
Don