Bogen model TPU100B is wall-mounted telephone paging amplifiers rated at 100 watts, respectively. It can also be rack-mounted. The TPU amplifiers permit paging from telephone and/or microphone; music input through an RCA jack or screw terminals; and voice-activated, variable level, music mute with fade back after page. These TPU amps include a night ringer which sends an electronic ringing tone signal through all speakers, alerting personnel of incoming calls. Jacks are also provided to bridge two TPU amplifiers to double the number of inputs and output power