For balanced, Low-Impedance microphones. High and low cut filters for tone control, 4.2 kHz and 330 Hz, 6 dB/octave. Phantom power, +22V DC for condenser-type microphones. Activate by default, cut Jumper J1 to disable. Responds to mute bus activation, via mute SEND module or switch-closure. Responds to both mute bus #1 and mute bus #2 by default (cut jumper(s) to disconnect individual mute bus). Two mute response modes (cut jumpers to configure); 1. Normally-ON - turns OFF during mute activation (most common) 2. Normally-OFF - turns ON during mute activation (functions as an ON/OFF switch, useful for zone-paging microphones in multi-amplifier systems). Connector; removable terminal block.