How to mask the caller ID for an On-Net Call (Extension to Extension) in Cisco CallManager 4.x

[TCC_2]

Resolution

In order to block caller ID from an extension to an extension, complete these following steps:

1. Create two new partitions, TransPartition and BlockPartition.
   
2. Create two new Calling Search Spaces, TransCSS and BlockCSS.
   
3. In the BlockCSS, add the BlockPartition as well as all the other partitions where you want the phones to call, for example, user_partition, and in the TransCSS, add the TransPartition.
   
4. Create a Translation Pattern in this way:
      
   • In the Translation pattern field, add XXXX or any other mask so that all the internal calls match this pattern.
     
   • In the partition field, add TransPartition.
     
   • In the calling search space field, add BlockCSS.
     
   • In the calling party transform mask, add 0000 or the number you  want to display.
     
     You can also choose Calling Party Presentation as Restricted in order to not display any number or ID.
     
      
5. In the line settings on the Manager phone(s), use these:
   

• In the partition field, choose BlockPartition.
  
• In the calling search space field, choose TransCSS.

 
Refer to How to change the caller ID display from one number to another and the external phone number mask is configured but does not work properly for more on blocking the caller ID display.