Denso BHT-1260BWB-CE User Manual page 68

BHT-1200 Series
"Output Device" tab is used to select an audio output device that emits
sounds for the BHT.
To select an audio output device, tap the "Output Device" tab.
Then choose "Speaker" or "Receiver".
"Input Device" tab is used to adjust the microphone volume when the
microphone is used as an input device.
To adjust the microphone volume, tap the "Input Device" tab.
Then use the slider to adjust the volume level.
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