Abstract: A tape playback unit is designed to transmit messages recorded on an endless loop dual channel recording tape. The tape contains a series of independent messages recorded on one channel and stop-start signals coordinated with the beginning and end of each message on the other channel. A multiple of receiving units each having an audio receiver as in a telephone receiver, hereafter referred to as an earphone, are connected to said playback unit and the independent messages contained on the tape are transmitted to the earphones. A control unit associated with each receiving unit intercepts the message being transmitted by the playback unit and permits transmitting thereof to the earphone only upon activation of a switch associated with the receiving unit, e.g. activated by a coin. The control unit further includes a timer associated with detecting means for detecting the beginning and end of each message, i.e. it detects the stop-start signals on said other channel.