Bells were soon added to stations for signaling, so an attendant no longer needed to wait for the whistle.Ī simplified example of an early circuit-switched telephone network. Alerting another user of the desire to establish a telephone call was accomplished by whistling loudly into the transmitter until the other party heard the alert. Users who wanted to communicate with persons at multiple locations had as many telephones as necessary for the purpose. History Ĭommercialization of the telephone began in 1876, with instruments operated in pairs for private use between two locations. The combination of the interconnected networks and a global telephone numbering plan allow telephones around the world to connect with each other. The E.163 and E.164 standards provide a single global address space in the form of telephone numbers. These standards have their origin in the development of local telephone networks, primarily in the Bell System in the United States and in the networks of European ITU members.

The technical operation of the PSTN adheres to the standards internationally promulgated by the ITU-T. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital in its core network and includes mobile and other networks, The network consist of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, interconnected by switching centers, such as central offices, network tandems, and international gateways, which allow telephone users to communicate with each other. It provides infrastructure and services for public telecommunication. The public switched telephone network ( PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. JSTOR ( December 2021) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed.įind sources: 'Public switched telephone network' – news

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