Calling No Null - Any way to block?

[bcclerkofcourts]

I have an employee who has started receiving several calls a day from a "Blocked Number."  The person on the other end of the phone never speaks; if my employee doesn't speak, the caller hangs up.  When I search in CDR (CUCM 9.1), the Calling No. and Calling No Partition are "null."  Is there a way to extract the blocked number so I can block the caller (short of watching a debug on my voice gateway all day)?

[Jaime Valencia]

This is Video Over IP, please move to a relevant area.

[Richard Simmons]

Doing a debug on the gateway won't show the calling party number, this is withheld by the carrier, there are several methods of blocking calls like this, it maybe easiest in this case to check the' Reject Anonymous Calls' box on the users Directory Number.

Hope this helps,

Richard