Combo Input Connector Female/XLR And �� Phone Jack For MIC/Line Inputs. Line 3/2 Stereo Line Inputs RCA Plugs To Connect Cd Mp3 Tape Deck Players. Main Out RCA Plugs To Connect The Mixer Receiver Or Amplifier. Signal Output Thru The Headphones Line/INSTR SW Input Select Switch Set Line 2/3 Level This Control Adjusts The Volume Of Signal Input Of Line 2/3. Peak Led It Lights Up Went The Input Signal Of Ch1 Is Too High. Ch 1 Gain This Control Adjust The Volume Of Signal Input Of Ch1. Phantom Power Supply On The XLR Connector Of Ch1. Phantom Led Indicates That Phantom Power Is On. USB Audio Interface Master Lets You Control Mixer s Overall Volume Level Clip Led Lights Up Went The Main Output Signal Is Too High Monitor To Control Volume Output Of The Monitor Jack. Power Led Indicates That The Unit Is In On Position.