The DM-3200 Digital Mixer has 16 channels of analog input. Each channel has a mic input and a line input, which are chosen on a per-channel basis via physical switches above the Trim knobs at the top of the mixer. Phantom power is also available (for condenser microphones) in banks of four channels. These switches should remain off unless you're using condenser mics.
The Rear Studio Stagebox is on the floor underneath the table to the left of the listening position. Mic inputs have XLR connections, line inputs have 1/4" TRS connections.
