RE: What is PCM
For planes the 7c is all the radio most of us will ever need. It has all of the programmable functions that you will want and still be a bit cheaper to purchase. If you are interested in helis in the future, the 9c might be the way to go. I fly a heli with a 7c and it works fine, but I recently purchased a 9c for all of the additional programming functions it offers. I would definitely recommend spending the extra bucks for the 9c if helis are in your near future, but for planes the 7c is all you need.