The PBX is owned and operated by the enterprise rather than the telephone company (which may be a supplier or service provider, however). Private branch exchanges used analog technology originally. Today, PBXs use digital technology (digital signals are converted to analog for outside calls on the local loop using plain old telephone service (POTS ).
Traditionally, a small business PBX (Private Branch Exchange) is a telephone switching system that manages incoming and outgoing calls for a company's internal users. A PBX is connected to the public phone system and automatically routes incoming calls to specific extensions. It also shares and manages multiple lines. A typical small business PBX system includes external and internal phone lines; a computer server that manages call switching and routing; and a console for manual control.
IP-based small office PBX telephone systems are highly programmable and can perform sophisticated functions, such as automatic call conferencing, click-to-call, and more.