In an exemplary embodiment of the present invention, the step of displaying the volume control menu window on the display unit converts the volume control menu window on the display unit to {HEAD ~ a volume control menu window} for the speakers when the external audio reproduction unit is released from {TAIL ~ the audio output port} 
In an exemplary embodiment of the present invention , the step of displaying the volume control menu window on the display unit converts the volume control menu window on the display unit to { HEAD ~ a volume control menu window } for the speakers when the external audio reproduction unit is released from { TAIL ~ the audio output port }
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