tl;dr: It records on specially coded squelch, a voicemail from a different CB radio to its memory. It then sends a messing to let the other CB radio, know that it had received the message. It will then alert the user that there is a message, and the user can then listen to it.-- mofosyne, Jun 17 2011 Semi-Baked since the advent of CB. Some CBers used to attach a cassette recorder to their set and play back the messages later.-- 8th of 7, Jun 17 2011 Well at the very least, the capability should be embedded in walkie talkies.-- mofosyne, Jun 19 2011 random, halfbakery