The four channels are there because you might want to control stuff in multiple locations from one source. Remember, I'm making single channel receivers that will react to individual channels. I can see the locomotive having the four channel board installed, and then using the individual receivers, react to a coupler signal, a headlight signal, markers, and perhaps smoke off/on status. Also, you don't have to use all four channels, but I can envision plenty of times you'd want to use more than one.
Fun fact, the four channels appear to be totally independent. That is, I can hold continuous transmission on one channel and manipulate the other channels with 100% recognition. The transmitter board we're using, as well as several different brand keyfobs, all will transmit one or all the channels and they're perfectly recognized by the receiver, and when any one goes active or inactive, it's immediately recognized. Given that fact, I don't see why I have to insure the other channels are not triggered simultaneously, this seems to be a non-problem.
A different problem does exist, that being multiple transmitters. If you have two transmitters trying to send at exactly the same time, then the messages do get lost. That's not something that is easy to control, I don't have a solution for that, but it has nothing to do with the design of my transmitter board. In point of fact, multiple transmitter boards are a problem.
