City Theatrical has posted this explaination of RDM on there web site:
http://www.citytheatrical.com/newsletter/RDM.htm
this is a pretty cogent explaination of RDM and it's usefulness along with an explaination of how CT has added RDM functionality to there wireless products. At EDI we have incorperated there wireless into our Scrimmer Sticks as an option. I've found in our testing that it's robust and stable not to mention a quick and easy way to add wireless option to a DMX512 product.
have a good one!
Tracy