The control unit controls the audio signal processing unit to adjust the volume control values for the audio output port by {HEAD ~ the volume control buttons} when {TAIL ~ the external audio reproduction unit} is plugged in the audio output port 
The control unit controls the audio signal processing unit to adjust the volume control values for the audio output port by { HEAD ~ the volume control buttons } when { TAIL ~ the external audio reproduction unit } is plugged in the audio output port
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH