About 3 years ago I purchased an Argent simplex repeater. Seemed like a neat thing to have. Played with it off and on and found out it could handle digital transmissions as well as voice.  The Argent info page is at: http://www.argentdata.com/products/repeater.html   I've messed with it a bit as has a friend of mine.   The repeater has the following general functions: Store and forward: receives a voice or digital transmission and then replays it over the air. This is the basic "parrot" function