Steve,
I'm not certain if you're in the correct place, you might be... These forums are geared towards supporting the ANSI E1.20 Standard. Which is a remote device management protocol over RS485 primarily for lighting products. That does not mean that it can't easily be adapted to be used with other types of products as well.
You might check out the Wikipedia page which will give you a high-level overview of the protocol:
http://en.wikipedia.org/wiki/RDM_(lighting)