The “IP” in IP phone system refers to Voice over IP, or having your phone calls routed over the internet or your local network (LAN). This is great for many reasons. First of all, you don’t have to use the telephone network of your telephony service provider for making calls, which will reduce your costs for phone calls.
At the same time, you are gaining many technical advantages by using IP technology for your telephony.
Users of a VoIP phone system simply plug their IP phone into the nearest LAN port. Then, the IP phone registers automatically at the VoIP phone system. The IP phone always keeps its number, and behaves exactly the same way, no matter where you plug it in – on your desk, in the office next door or on a tropical island.