Patent ID: 8811625

Claim:
A headphone system installed in a portable electronic device configured to output sounds, comprising: an audio wire, configured to transmit audio signals; a sound output device, configured to receive and demonstrate the audio signals transmitted by the audio wire; an audio processing unit, configured to receive audio data and output the transmitted audio signals corresponding to the received audio data via the audio wire according to a control signal; an automatic reel, wound around an axis of the automatic reel by the audio wire and configured to roll up the audio wire around the axis of the automatic reel; a length detection unit, configured to detect a rotating distance and a rotating direction of the automatic reel by synchronously rotating along the axis of the automatic reel when rolling up the audio wire; and a control unit, configured to output the control signal to the audio processing unit and to control the audio processing unit to stop the output of the transmitted audio signals when a detection result of the length detection unit shows a length of the audio wire pulled out from the automatic reel is smaller than a predefined value.