Core Issue
For a specific Directory Number (DN), although Call Forward Busy (CFB) is set to direct calls to voice mail, calls take a long time to transfer to voice mail when a user is busy.
Resolution
The reason for this is that CFB does not get triggered if any of the following conditions are set. Instead, the calls get transferred after Call Forward No Answer (CFNA) is triggered.
Basic things to check for in this case are:
- Find out if the DN is shared. CFB does not work with shared DNs.
- Check the Call Waiting field in the Directory Number Configuration page. This should be set to off.
By default, Call Waiting is enabled system-wide. Depending on your requirements, Call Waiting can be turned off on individual phones or system-wide in Cisco CallManager.
Use the following procedure to disable Call Waiting system-wide.
- In Cisco CallManager, select Service > Service Parameters.
- Locate the CallWaitingEnable parameter and change the drop-down to False.
- At the top of the page click Update.
- Repeat the above steps for all Cisco CallManagers in a cluster.
Use the following procedure to disable Call Waiting on individual phones.
- Seach for the DN (or phone).
- Select the DN at the left (if you searched by phone).
- Find the Call Waiting setting on the page and change the drop-down to Off.
- At the top of the page, click Update.
- At the top of the page, click Restart Devices.
- Click OK.
- You can also check the value for Forward Maximum Hop Count in the Service Parameters. This should be a non-zero value. Set it to the recommended value (12).
For further information, refer to Cannot Transfer Second Incoming Call.
