I presume retail automatic execution system at CBOE? http://www.cboe.com/LearnCenter/pdf/techatcboe.pdf
I don't know what it is either, beyond what is stated in that pdf. I just Googled it, and that was the first hit
RAES was referenced because it was essentially the opposite of what exists nowadays. i.e. quotes would often go stale or out of alignment with other strikes and you could hit those bids and offers. Obviously nobody was trading back in those days, but I'm not talking about the 1970's, this was a frequent occurrence in the early 00's.