Sony SRS-BTS50 - Manual (Page 82)

Microphone
To adjust the volume
Press the VOL +/– button.
The power indicator (green) flashes 3 times when set to the lowest or highest
volume level.
Tips
You cannot adjust the volume when not talking.
If the caller cannot or can barely hear your voice, talk into the microphone of the
system.
To end a call
Press the
(call) button.
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