While true, some call LCN’s something else. I was understanding the question to be about never hearing the term LCN. I offered what I recalled when manual programming was still the norm and we needed to be aware of such settings in order to track these systems. Today, I’ve gone the route of automatically downloading from RR and installing entire systems as I’m sure most everyone has, so terms such as color code’s, LCN’s etc. don’t get the attention they once would. (I could have easily googled LCN, where I’m sure I would have picked up what other types of systems rely on them, but then, so could the originator of the question… didn’t figure it was what he was after. My comments about LCN not being that prevalent in this area was only an attempt to say “Don’t worry, the terms don’t mean as much as the used to now that we can use the automatic download and programming services.)