I am only a little familiar with 3CX. I went through the basic certification course, but I just recently powered down my server). In most, if not all of these types of VoIP systems, the server will store the configuration which gets pushed out to the phones. I haven't seen a system where the server will query the phone programing and update its own configuration. It is almost always a one-way configuration.

I have seen this with other systems as well, the user makes changes that get overridden by the server configuration.

Unfortunately, I do not remember if 3CX has an interface for the users to make changes. Generally, that is the safest way to make phone changes, by only changing the settings on the server-side and not directly through the phone. as far as the server is concerned, the phones are supposed to be a certain way.

That being said, I don know all the ins and outs of a 3CX system specifically, so there might be a way to do what you are trying to do.

In a premise PBX, the phones are generally very dumb They can't even light up a button unless the PBX says to light it up. An IP phone typically has more intelligence in them.

David
Tele Express Business Systems