Windows 7 has a built-in feature for changing the Communication settings. Using this settings, users can specify the desired volume control when they place or receive a telephone call in their PC.
This settings can be accessed via Control Panel -> Hardware and Sound -> Change System Sounds -> Select Communications tab
Any one of the following options can be set when it detects communication activity
- Mute all other Sounds
- Reduce the volume of other sounds by 80%
- Reduce the volume of other sounds by 505
- Do nothing.