Plantronics MCD100-M USB Speakerphone 8
3 Using Your MCD100-M USB Speakerphone

Volume Up, Volume Down, and Mute

1 Press the down arrow (left button) to decrease the
speaker volume.
2 Press the up arrow (right button) to increase the speaker
volume.
NOTE A prolonged press of the Volume buttons will increase or
decrease the volume several levels until you stop pressing the
button. The MCD100-M will beep when a volume up button or
volume down button is pressed and a series of beeps when a
prolonged press is performed. Each beep signals one level of
volume increase or decrease.
3 Press the microphone icon (middle button) to mute
the microphone. A blue light will flash indicating that the
microphone is muted.
4 Press this button again to unmute. The blue light will
become solid indicating the microphone is unmuted.