Waiting for a call, but can’t let your device ring? There are various settings groups called profiles, which you can customize with ringing tones for different events and environments.
Select Menu > Settings > Profiles.
Select the desired profile and from the following:
Activate - Activate the profile.
Customize - Modify the profile settings.
Timed - Set the profile to be active until a certain time. When the time set for the profile expires, the previous profile that was not timed becomes active.