Aiphone PM-30 is a mixer amplifier designed for commercial and industrial applications, providing paging, announcement, intercommunication, and background music systems. It features 4 microphone inputs for high and low impedance microphones, 4 auxiliary inputs for signal sources like FM tuners, cassette players, and phonographs, and a telephone input. The PM-30 has independent volume controls for each input, master volume control, bass and treble tone controls, and an overload LED pilot lamp.