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