You need a 4 place unit. You can hide most of the wires under the carpets and in the side pockets. The unit I've used turns itself off automatically if nothing plugged in. If I remember correctly it needs a 9 volt battery. It just needs to be plugged into one set of sockets (1 mic - 1 tel). It worked very well! The normal PTT operates it although there separate PTT switches on the unit.