How to manipulate calling number for outgoing calls from CUCM to PSTN

[j.smith@sepidarsystem.com]

Hi

I have a CUCM and a SIP trunk modem. The sip trunk modem is connected directly to the Mikrotik firewall and there is a sip trunk configured from CUCM to PSTN. I want to keep my original calling number instead of my office number to be displayed while having outbound call (I'm using DID feature). I set the original calling number in  these fields:

1- External phone number mask in Directory number 

2-Route pattern 

3-Route Group 

But it didn't work and the office number is displayed.

Is it necessary to set prefix digits?(for example the area code or ZIP code)

Is it necessary to configure Calling Party Transformation CSS in SIP Trunk or device pool?

[mumbles202]

Possible the carrier is modifying the Caller-ID on their equipment and not honoring what you're sending?  

[Shalid Kurunnan Chalil]

Hi there,
can you please paste the Dialed Number Analyzer output?

If all good from UCM side, also see if you have any digit manipulation at the gateway level.
also, there may be a chance that carrier manipulating the CLID to the billable DID.