3 inputs (terminal strip or RCA jacks and XLR on channel 1)3 auxiliary sound source inputs, 1 with XLR mic inputMusic on hold with separate level control and voice activated mute4/8/16-ohm, 70V or 25V operationAuto-summing speaker outputs: 25/70V and 4/8/16-ohmFront panel volume, bass and treble controls50Hz-15kHz frequency response600-ohm telephone line input with volume, bass and treble controlsAuto mute function, auxilary output and music on hold output with separate level controlManual muting contactsRack or wall mountable