What do you want to define in that field that will be by extension? You want to send the extension number there?Define Remote Party ID - Calling Party : User Part by extension. It can't be in the users Outbound Caller ID.
Yes, i'm aware. Not the issue cause i'm also the providerKeep in mind...because of the proliferation of Spam calling, many providers will no longer permit a caller ID that is not in a standard format, as used within the country, that is, if they even allow numbers, that were not issued by them..
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.