This is the new model which has a switch to work two different ways. If you put the switch in position 2 it works on office supervision. You can hook it up to a Xlink, marry it to your cell phone,change the setting in the Xlink to broadcast reverse battery on a answer which it can do. The new controller will read the reverse battery and collect the coin or return it based on a ring no answer,busy signal, SIC tone or answer. It doesn't get any better then that.