Phone Systems

A telephone system, PBX (abbreviated PBX) or private branch exchange (PBX) is a switching device having a plurality of terminal devices such as telephone, fax, answering machine combines both among themselves and with one or more lines of the public telephone network.


In the early 1930s, the telephone systems of internal and external connections are still made with so-called spacers. Until the late 1970s, telephone systems were built in an open frame mechanical design, then in metal cabinets. They consisted mainly of hunters call, group voters, voters line, line circuits, official transfers, and an attendant. These were replaced in the 1980s due to fully digital systems, the basic functional component of a switching matrix, and whose input and output lines were switched by a control unit. The family was a PBX telecommunications solution that was offered in the 1980s by the German Federal Post for households.

From 2000 it was becoming more fully IP-based solutions are used, and thus move away from circuit switching towards pure packet switching of digitized voice data.

The virtual PBX increasingly replaced the traditional ISDN-PBX in the enterprise. Especially small and medium enterprises benefit from virtual phone systems, because with the help of web-based communications solutions, allows the integration of mobile devices or instant messaging implemented in corporate communications. In addition, virtual PBX much more flexible than stationary systems and can be extended due to the outsourced server capacity by any number of employees. While the major providers such as Telecom and Vodafone business with virtual phone systems detected late to have had, especially small companies like Placetel, nfon and Sipgate involved in the market development in Germany.