The silence threshold is used to determine what silence is. The lower the threshold, the more sensitive it is.
To set the Silence Threshold:
1. Login to the system administration.
2. Navigate to 'Settings: Voicemail'.
3. Under the 'General Voicemail' group there is a 'Silence Threshold' option.
4. Enter a value in seconds (e.g. 128) and click on the 'Save' button.