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