Microphone summing with 4 inputs and 1 outputs. Nominal input level from -30 dBm to + 10 dB. 24 V DC power supply (via pin 4 of the output connector). Maximum consumption 5 mA (without microphones). Input impedance 1.5 kohm (at 1 kHz) symmetrical. Output impedance 200 ohm symmetrical. Dimensions 144x82 mm.