AtlasIED AA100PHD 4-Input 100W Mixer AmplifierThe AA50PHD is for distributed business paging and background music systems, small to medium speech privacy systems, and where music plus paging is required. With one microphone line input and three stereo line inputs, the AA50PHD will accommodate a variety of input sources including paging microphones, media players, and digital music receivers. The AA50PHD includes a patent pending automatic system test, the Push Here Diagnostic. The PHD button is