IP PBX

• abstract: PBX is a system that connects telephone extensions of a company to outside public telephone network as well as to mobile networks. An IP (Internet Protocol) PBX (Private branch exchange) is a PBX that provides audio, video, and instant messaging communication through the TCP/IP protocol stack for its internal network and interconnects its internal network with the Public Switched Telephone Network (PSTN) for telephony communication.

以上来源于: WordNet