What is an IP PBX?

An IP PBX is a hosted telephone system that operates by delivering voice transmissions over a data network, using the internet protocal (hence the term "IP" PBX). An IP PBX may be VoIP (Voice over Internet Protocol) based or interconnect with the publicly switched telephone network (i.e. traditional analog telephone service).

There are many different types of IP PBX systems. Some are hosted by the telephone service providers, while others require on-site hardware for the company's internal call processing and routing.