The input parameters control aspects such as input level switching and phantom power activation.
Int(ernal) Mic activates the built-in electret microphone.
Ext(ernal) Mic activates the XLR input.
External Phantom-powered Mic (Ext 48V Mic) activates a 48 volt phantom power supply for the XLR input. This setting applies only when a microphone is connected to the XLR input.
Inst(rument) activates the 1/4 inch input.