Rocket scientists give us inexpensive phone service
Have you thought of your phone system being embedded on an ordinary computer? I use a phone system based on the open source software FreeSWITCH®. It saves me money by allowing me to get the full use of my Internet line, while avoiding the extra cost and taxes of dedicated phone lines. With FreeSWITCH® and other SIP solutions, the concept of "lines" goes away. Everything is a network packet, so the number of simultaneous calls is only limited by your computer speed and network bandwidth. With FreeSWITCH® I can have an unlimited number of stations and incoming and outgoing DID's and the whole configuration is defined in one software program.
FreeSWITCH® is the opensource version of the engine that runs Barracuda Network's CudaTel. If you want a polished, finished product with an easy user-interface, you should buy the CudaTel product. If you are a tinkerer, or need a highly customizable, applications-driven version, you'll want the bare engine from FreeSWITCH®