Plantronics VistaPlus DM15 Notice D'utilisation page 6

CONNECTION & SETUP
GB
SETTING THE RECEIVE VOLUME
Refer to Figure 4 Top view of buttons and tone control
VistaPlus has a volume control which you can use to adjust the volume
of your caller's voice. Step the volume up and down by pushing the
volume switch on the top of the adapter until it is set at a comfortable
level. The adapter will maintain this volume regardless of the volume
of the incoming call and so you should not need to adjust the receive
volume very often. Receive volume can be adjusted while you are in a
call, if required.
SoundGuard Digital protection ensures that the volumes do not exceed
legally defined levels over the course of a working day and will protect
you from sudden high volume noises which may occur.
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