Best practice for dealing with cold (blind) transfers to unused extensions


Recently I’ve noticed several unused extensions with Unread voicemails.

I’m not sure of all the ways this is happening, but one scenario I have found is an agent is cold transferring to an unused extension (even after being told cold transfers are not allowed). Sometimes the extension is simply no longer used (ex-employee) and sometimes its an accidental dial. Who ever setup this system, created 100s of unused extensions, all enabled with vm. I’ve tried the following to prevent this from happening, but each of them results in the customer hearing a “…not in service” and then the call is dropped.

  1. Disabled voicemail
  2. Disabled extension
  3. Deleted extension

Is it possible to have these calls forwarded to an operator or reject the forward and re-ring the original extension? Also, is it possible to systematically prevent cold transfers? Any other ideas or best practices?

UCM6510 firmware

Thank you in advance for your help.


Unused extensions --> just forward immediately to the operator.