ORIGINAL: HarryC

The Futaba radios with a 9 in the name are 8 channel radios. In PPM they have 8 channels.

In PCM they add a 1-bit thingy which allows a 2 position switch, there is no adjustable end points, travel etc. Even the rubber band escapements used on single channel push button radio in the 60s had 3 positions. By the early 1970s MacGregor were selling a radio with a proportional stick for rudder and a button for 3 position elevator. Thirty years ago they did not have the cheek anymore to call that a 2 channel radio, it was called the 1+1 and that +1 had one more position than Futaba's 9th "channel". Futaba's 9th "channel" is fine for something like retracts, in those situations it does the job as well as a proper proportional channel would do. But if you allow Futaba to call that a channel, then they can give you any number of those and call them channels - a box with 4 switches could be a 4 channel radio. Or a "9 channel" radio could be 4 proportional channels and 5 of Futaba's extra channels which would be useless for having a second aileron servo, flaps, spoilers and so on. Don't let them get away with calling it a 9 channel radio.

H