Caller ID displays information about the caller on the screen of Caller ID-enabled phone. Caller ID data is transmitted between the first and second rings. When a call is answered immediately after the first ring, caller ID may not be available.
You can set up a customised Caller ID in you PBX web panel. For example, you can set extension 1000 into Rose Seror. So next time when she calls you, you’ll see her name on the screen directly instead the number 1000 that you should recall yourself who owns extension 1000.