that was back in the days when you had to plug in different crystals to get different frequencies now except for the very cheap toys everyone uses digital devices which can alter the connection between transmitter and receiver just using software ( I class firmware as software) I am old enough to remember when we use to fly using homemade transmitters and receivers and just one channel with a clockwork control system where the only thing you sort of controlled was the rudder you had to set the speed before flight by adjusting the engine revs and you landed when you ran out of fuel the control you had was not proportional what you had was once (if) you got into the air you would press the button on the transmitter and the receiver would operate a release which let the clockwork rotate one click which would let the model turn left when you were on the correct heading you pushed the button again which allowed the clockwork to turn to the next position which would be back to straight then if you pushed the button again you would steer right then with the next press back to straight and then back to start the series off again (left,straight, right,straight, left, straight, right, straight) and that was all the control you had over the model until it came back to ground I remember many people running after models that had lost the connection between transmitter and receiver don't let anyone say it was the good old days, a good day was when you went home with most of your model in one piece and your radio system had not burnt up in your hand the radios used the old valves as transistors had not come outside of the labs, people would talk about their dream system which would have 2 or even 3 channel's.
