CUCM SIP Trunk remove prefix 0 when a call is transfered.

[Waldo Roca Martin]

Hi

We have a SIP trunk to ISP for external calls. When a call incoming trough the trunk we add prefix 0 on "Incoming Calling Party Settings".

But when a user make a "blind transfer" (this means press transfer button 2 times without wait the call is answered) the call on the transfered phone is showed without "0" on the calling number. So if the call is not answered the call is registered on missed calls with not "0".

There is a way to keep the prefix in this situation.

Te version of CUCM is 10.5.

Thank you

Best Regards

[Deepak Rawat · Accepted solution]

Hi Waldo,

Please perform the below in order to prefix 0 on missed incoming calls:

1.       Go to Call Routing -> Class of Control -> Partition. Create a new partition

2.       Go to Call Routing -> Class of Control -> Calling Search Space. Create a
new CSS and add the partition you created.

3.       Go to Call Routing -> Transformation Pattern -> Calling Party
Transformation Patterns. "Add New" and enter a Pattern with a wildcard like "XXXXXXXXX",
(9 digits or what ever your calling pattern is).

Add 0 in the "Prefix digits" field.

                Finally select the partition you have created and save.

4.       Go to the SIP trunk configuration and look for "Incoming Calling Party Settings",
uncheck "Use device Pool CSS" and select the Calling Search Space that reaches the
partition of the Transformation Pattern.

5.       Save the change and reset the SIP Trunk (after business hours to avoid call
interruptions) to apply the change.

More information can be found on below link:

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/admin/8_5_1/ccmfeat/fsgd-851-cm/fscallpn.html

Regards

Deepak

[Waldo Roca Martin]

Hi

Thank you

 I already did that and doesn't work neither. The behavior is the same as use prefix option. When you transfer the call, the "0" is removed on the transfered phone.

Best regards