Purpose: To quickly switch earphone output from listening to a music player to listening to microphone output.

Concept: You are listening to music through your headphones. Someone enters the area and starts talking to you. You hit an onscreen or hardware button, and immediately you are listening to that person through the microphone.

Alternate use 1: Sound amplifier for hearing impared.

Alternate use 2: People see that you are listening to music and think that you are not listening to their conversation - but you are !

Alternate use 3: Connect the line output of a keyboard, guitar or bass to the mic input, use device as practice/headphone amp.