Plantronics MCD100-M manual B), C)

Plantronics MCD100-M USB Speakerphone 6
B) In step B, you will set the Speakerphone you want to use.
Make sure the Speakerphone is set for MCD100-M by default.
If it is not, select then select MCD100-M in the drop down lists
under Speaker and Microphone. Click Next.
At this point you may click Test to play a tone through the
MCD100-M speaker and adjust the speaker volume. For
Windows XP the speaker slider will not adjust the volume
on MCD100-M (because of how MCD100-M is required to
enumerate to meet Microsoft Office Communicator 2007
Certification requirements) so the volume must be adjusted using
the MCD100-M controls on the unit. The microphone can also
be adjusted at this point using the slider. Both sliders operate
correctly with Windows Vista.
C) In step C, you will set the audio output location for your
Microsoft Office Communicator 2007 program sounds. It is
recommended that you use your PC speakers for this setting if
you have a sound card and speakers available because system
sounds can be distracting when played through MCD100-M
during a call.
NOTE This step only controls Microsoft Office Communicator
2007 system sounds. Windows system sounds must be
managed through “Sounds and Audio Devices” in Control Panel.
To make any further adjustments to Windows audio, do the
following:
For Windows XP, click on the following: “Start”, “Settings”,
“Control Panel”, and select “Sound and Audio Devices”. From
there select the audio tab and make any further adjustments to
MCD100-M settings for Sound Playback (speaker) or Sound
Recording (Microphone).