In an IP Telephony environment with Cisco CallManager, calls are forwarded to voice mail within two or three rings. This gives the user very little time to pickup the call.
Although Cisco CallManager is unable to control the actual number of rings explicitly, a user can adjust the Forward NoAnswer Timer value in the service parameters. This is the value used for waiting; to allow x amount of rings. The default is usually 12 seconds, which allows two to three rings before diverting to voice mail.
This value can be increased for the number of rings required (assuming 4 seconds for each ring). For example, if it rings five times, set this value to 20 seconds.
Use the following procedure to set the value.
- From the Cisco CallManager Admin, select Service > Service Parameters.
- Select the Server from the drop-down list.
- Select Cisco CallManager from the service drop-down list.
- Search for the Forward NoAnswer Timer field on this screen and set the desired value here.
- Click Update on the top of the screen.
Note: This is a global parameter, so changing this value will affect the behavior of all phones. It cannot be changed on a per user or telephone basis. When changing this value be sure to do so for all CallManagers in the cluster.
For further information, refer to Configuring the Forward No Answer Timeout in Cisco CallManager 3.x.