For Balanced, Low Impedance Microphones. High and Low Cut Filters for tone control, 4.2 kHz and 330 Hz, 6 dB/octave. Phantom Power, +22 VDC for condenser-type microphones. Active by default, cut Jumper J1 to disable. Signal At Input Terminals Activates Both Mute Bus # 1 and Mute Bus # 2 by Default (cut jumper(s) to disconnect individual mute bus). Connector: removable terminal block (M-41S)