| 4 inputs: 1 MIC (Lo-Z), 1 AUX (Hi-Z), 1 TEL, plus 1 selectable MIC or AUX Each input controlled by an independent volume control Treble and bass controls AUX muting by external contact closure for push-to-talk microphones TEL input for telephone paging applications TEL input voice-activated (VOX) mute over AUX input | Variable threshold for TEL input voice-activated mute Output jack to connect a recording device or booster amplifier Thermal protection and electronic shutdown Rack mountable with accessory mounting kit (model RPK50) Listed to UL Standard 60065 for U.S. and Canada |