Caller ID issue - Default not used on SIP trunk per case

[George Ts]

Hello,
I am having the following scenario:
3cx_slave ---> Bridge ---> 3cx_master --> SIP Trunk ---> VoIP Provider

I have configured a default Caller ID on the 3cx_master's SIP Trunk with the VoIP Provider, which is expected to be added in the SIP From Header, when 3cx_master makes outgoing calls to the VoIP Provider.

When a 3cx_master extension makes a call to the VoIP provider, I can see indeed that the SIP From header uses the Default Caller ID.
When a 3cx_slave extension makes a call that goes to the 3cx_master (Bridge) and then to the VoIP provider, the SIP From header uses the actual 3cx_slave's extension number, instead of the default Caller ID configured on 3cx_master.

My questions:
1. Why does this happen?
2. When is the default Caller ID used on a SIP trunk and when is it overridden?

Thank you,
George

 

[lneblett]

This may provide some insight (read towards the bottom):
https://www.3cx.com/blog/voip-howto/caller-id-processing-distinctive-ringing-alert-info/
The bottom line is the field that the CID is being presented and how it plays with the rules otherwise of CID outbound and how to makes it so that master calls and slave call can be handled so that both end up being the same when processed thru to the provider. The may require some examination and experimentation of the headers and hopefully others may be able to short-cut this and provide more specifics.
The bottom line is that because the slave call is not being processed by the slave trunks, the extension CID is coming across as though it were an extension to extension call. As the master system does not see this as a master extension, it passes the call as though a forward maintaining the original CID.
If you want all calls leaving this trunk to have the same number regardless, then your provider may be able to override the seen CID with the one you want.

 

[leejor]

You may be able to change the number through some of the outgoing trunk parameters mentioned in the first post here....

https://www.3cx.com/community/threads/outbound-parameters-problem.21508/

However, changes in these options can have a detrimental affect on some outbound calls that is not immediately apparent, so do some testing on various call types, and make note of the original settings.

 

[George Ts]

@lneblett , having a master 3cx server present the actual extension number incoming through a bridge makes sense. But I would not expect it to handle their outbound caller ID (while exiting to the SIP Trunk) in a different way than its own master extensions. Which is what happens, actually, for whatever reason.
The workaround I applied is to go to the master's SIP Trunk to VoIP provider - - > Caller ID - - > and add an Outbound Caller ID that matches the slave extensions' pattern. (see attachment)

@leejor this is a safer way than messing with SIP Trunks - - > Outbound Parameters, but what you suggest sounds effective, as well.
Thank you both for your responses,
George