Canon opture 10 Instruction Manual page 315

~
Check the position of the speaker volume
lever in the [Conversation] window. Move
the lever to the right until the volume
indicator on the right operates.
~
Check if the sound device is set to [Mute] in the [Control Panel].
1. From the [Start] menu, select [Control Panel].
2. Select [Sounds, Speech, and Audio Devices].
3. Click [Adjust the System Volume].
53