If I remember correctly the plates have two catches on each side about a inch down for each corner, I actually have a spare ten button plate that was left in my coach, probably when it was built. These switches are all programed especially for what they control I think. There are a couple of people in a couple of these forums that know how this whole multiplex system works and how to program.
I have never had a problem with any of mine,,,knock on wood,,,!
