What is PBX?:
PBX (Private Branch eXchange) is a privately owned telephone switching system for handling multiple telephone lines without having to pay the phone company to lease each line separately. A PBX essentially takes the place of the phone company's Central Office within the company by acting as the exchange point, routing calls. With a PBX in place, each phone only needs an extension, not a phone number, and the PBX handles all calls made from desk-to-desk within the company.

Currently, there are four distinct scenarios in use:

1. PBX (Private and Circuit Switched)
   See definition above.
2. Hosted/Virtual PBX (Hosted and Circuit Switched)
   PBX is located at and managed by the telephone service provider, and features and calls are delivered via the Internet. You just sign up for a service, rather than buying and maintaining expensive hardware. This essentially removes the branch from the private premises, moving it to a central location.
3. VoIP PBX (Private and Packet Switched)
   Uses the Internet Protocol to carry calls. Companies need packet switched networks for data, so using them for telephone calls was tempting, and the availability of the Internet as a global delivery system made packet switched communications even more attractive.
4. IP Centrex or Hosted/Virtual IP (Hosted and Packet Switched)
   Combination of 2 and 3 above.

History of PBX and How it Can Help You:
Historically, the expense of full-fledged PBX systems has put them out of reach of small businesses and individuals. However, since the 1990s there has been a large set of small, consumer-grade and consumer-size PBXs available. And because of the scenarios above, you have many more choices on what can help your business specifically. Inphonite, LLC develops and markets professional, automated phone messaging systems and interactive computer telephony products that improve the profitability and productivity of a wide range of organizations.