Talkback, 1 Zone, Page Control provides one zone of talkback paging and supports up to 2 talkback and/or 40 one-way speakers and has a background music input, optional alert tone and repeated alert tone.- Interfaces With Telephone System Via A Loop Start C.O. Line Position Or Via A Bi-directional System Page Port With Contact Closure.- May Be Accessed From A Dedicated Single Line Telephone Set).- Background Music Input.- Transmit And Receive Volume Controls.- Optional Alert/Repeated Alert Tone.- Inhibit.- Power Supply Required.