A method includes comparing a voltage level detected by a detection circuit to a set of threshold voltages to determine a type of a headphone, determining the headphone to be a first type when a first signal travels through the first path to ground, and determining the headphone to be a second type when a second signal travels through the second path. The detection circuit includes a first path, a second path, and a bias capacitor. The headphone of the second type includes a plug that has a microphone connection.