A telephone operator manually connecting calls with cord pairs at a telephone switchboardA modern central office, equipped with voice communication and broadband data capabilities
A telephone exchange, also known as a telephone switch or central office, is a crucial component in the public switched telephone network (PSTN) or large enterprise telecommunications systems. It facilitates the interconnection of telephone subscriber lines or digital system virtual circuits, enabling telephone calls between subscribers.
The terminology used in telecommunications has evolved over time, with telephone exchange and central office often used interchangeably, the latter term originating from the Bell System. A central office typically refers to a facility that houses the inside plant equipment for one or several telephone exchanges, each catering to a specific geographical region. This region is sometimes known as the exchange area. In North America, the term wire center may be used to denote a central office location, indicating a facility that provides a telephone with a dial tone.[1] Telecommunication carriers also define rate centers for business and billing purposes, which in large cities, might encompass clusters of central offices to specify geographic locations for distance measurement calculations.
In the 1940s, the Bell System in the United States and Canada introduced a nationwide numbering system that identified central offices with a unique three-digit code, along with a three-digit numbering plan area code (NPA code or area code), making central office codes distinctive within each numbering plan area. These codes served as prefixes in subscriber telephone numbers. The mid-20th century saw similar organizational efforts in telephone networks globally, propelled by the advent of international and transoceanic telephone trunks and direct customer dialing.
For corporate or enterprise applications, a private telephone exchange is termed a private branch exchange (PBX), which connects to the public switched telephone network. A PBX serves an organization's telephones and any private leased line circuits, typically situated in large office spaces or organizational campuses. Smaller setups might use a PBX or key telephone system managed by a receptionist, catering to the telecommunication needs of the enterprise.
A telephoneexchange, also known as a telephone switch or central office, is a crucial component in the public switched telephone network (PSTN) or large...
A telephoneexchange name or central office name was a distinguishing and memorable name assigned to a central office. It identified the switching system...
Hungarian engineer Tivadar Puskás proposed the telephone switch, which allowed for the formation of telephoneexchanges, and eventually networks. In the United...
the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephoneexchange. The exchange completes the call...
Guardian Exchange was an underground telephoneexchange built in Manchester from 1954 to 1957. It was built together with the Anchor exchange in Birmingham...
The AXE telephoneexchange is a product line of circuit switched digital telephoneexchanges manufactured by Ericsson, a Swedish telecom company. It was...
(KTS) to the private branch exchange (PBX). A business telephone system differs from an installation of several telephones with multiple central office...
telephone systems took advantage of the exchange principle already employed in telegraph networks. Each telephone was wired to a telephoneexchange established...
Kingsway telephoneexchange was a Cold War-era hardened telephoneexchange underneath High Holborn in London. Initially built as a deep-level air-raid...
of the telephone chronicles the development of the electrical telephone, and includes a brief overview of its predecessors. The first telephone patent...
telephone call or telephone conversation (or telcon), also known as a phone call or voice call (or simply a call), is a connection over a telephone network...
dialing. It is used when initiating a telephone call to transmit the destination telephone number to a telephoneexchange. On the rotary dial, the digits are...
data record produced by a telephoneexchange or other telecommunications equipment that documents the details of a telephone call or other telecommunications...
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed...
invents the telephone switchboard exchange (later working with Edison). 9 October 1876: Bell makes the first two-way long-distance telephone call between...
it has capacity for approaching 100 million telephone numbers. The code is used at 170 telephoneexchanges in and around Greater London as part of the...
its respective numbering plan area. The telephone number consists of a three-digit central office (or exchange) code and a four-digit station number. The...
20th century. The switchboard was an essential component of a manual telephoneexchange, and was operated by switchboard operators who used electrical cords...
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony...
public switched telephone network (PSTN). Landline services are traditionally provided via an analogue copper wire to a telephoneexchange. Landline service...
The Nippon Telegraph and Telephone Corporation (NTT) (Corporate Number: 7010001065142) is a Japanese telecommunications holding company headquartered...
number may have different lengths. It shows which exchange the remaining numbers refer to. A full telephone number is usually made up of a country code (required...
or territory. All local telephone numbers within the four areas have eight digits, consisting (mainly) of a four-digit exchange code and a four-digit local...
telegraph and telephone services). Telephone companies are common carriers, and in the United States are also known as local exchange carriers. With...
Lantau Island Clearwater Bay – East TelephoneExchange Tower, 38 Clearwater Bay Road Causeway Bay – East TelephoneExchange Tower, 38 Leighton Road, Causeway...
The invention of the telephone was the culmination of work done by more than one individual, and led to an array of lawsuits relating to the patent claims...
telephoneexchange provided the solution for establishing telephone connections with any other telephone in service in the local area. Each telephone...
A telephone keypad is a keypad installed on a push-button telephone or similar telecommunication device for dialing a telephone number. It was standardized...
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