Original sentence: Virtual PBX (or IP PBX) allow companies to control their internal phone network over an existing LAN and server without needing to wire a seperate telephone network
Edited sentence: A Virtual PBX (or IP PBX) allows companies to control their internal phone network over an existing LAN and server without needing to wire a seperate telephone network.There is a rise in VoIP software to support internal and external company communications the most common of which is the Virtual PBX (Asterisk PBX and YATE for Linux, Axon PBX for Windows)