The Public telecommunications network (PTN) includes the landline networks of the local and long distance carriers, the cellular networks, and satellite service. Switches automatically establish and disconnect circuits between communicating parties on demand.
Prior to the introduction of cellular service, virtually all switched service was provided by the wireline telephone system. The system’s two billion miles of fiber and copper wire remain the backbone of the information and communications infrastructure, with the cellular and satellite wireless technologies serving mobile users as extended gateways to the wireline and wireless networks. The PTN provides both switched telephone and data services and long term leased point-to-point services.