Model #TBA15 Talk Back Amplifier Two Way Talk Back Amplifier 15-Watt, 2-Way Amplifier The TBA15 Two Way Talk Back Amplifier allows a paging system to be used for hands-free, two-way conversation between a telephone system and remote speakers.The TBA15 uses the system’s speakers as microphones and feeds this signal out to a telephone line.When the TBA15 senses an audio signal on the telephone line, it automatically switches its 15W amplifier on and uses the speakers in the system conventionally. Control of speech direction is maintained at the telephone handset. Read More   $461.16