As in many other countries, the United Kingdom is retiring its part of the global circuit-switched public switched telephone network. [1] [2] [3]
British Telecom, the country's dominant telco, announced its intention to switch off its PSTN infrastructure by December 2025, including both copper baseband landline telephone connections and its ISDN network. [2] Openreach, the major telecommunications infrastructure provider in the United Kingdom, is also due to retire its Wholesale Line Rental service. [4]
This process has been planned since 2017, and will roll out in a series of phases. [5] All providers are expected to implement Voice over IP and other IP-based network services to replace copper PSTN and ISDN connections. [6]
All major British telcos. including other Broadband Stakeholder Group companies such as Virgin Media and Sky UK that have their own infrastructure, will also cease to support both copper PSTN and fibre ISDN connections. [7] [8] Instead, analog landline telephones will be expected to connect to adaptors on home routers, and businesses connecting to the PSTN via ISDN connections will be expected to move to SIP connections to the VoIP network, a transition that has already been performed by many companies.
Voice telephony will continue to follow the E.163 and E.164 standards, as with current mobile telephony, with the interface to end-users remaining the same. Traditional analog telephones will continue to operate via traditional analog phone sockets, but with those phone sockets now terminating at the on-premises router or PBX. No changes will need to be made to the mobile phone networks, which already interconnect via data networking technologies.
Copper landlines will continue to be used for ADSL and VDSL Internet access for the time being. Fibre to the premises Internet access is planned to be rolled out nationally, allowing the eventual retirement of the entire copper telephone network. [9] BT Openreach's copper plant has been reported to have billions of pounds of scrap value, even after accounting for the cost of removal, with over a million tonnes of copper buried under the streets. [10] [11] Full retirement of the copper access network is expected to stretch into the 2030s. [11]
One problem with the replacement of the copper last mile is the discontinuation of electrical power to devices via the phone network, including critical devices such as health monitors. Work is in progress to address these problems. [12]
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work on the standard began in 1980 at Bell Labs and was formally standardized in 1988 in the CCITT "Red Book". By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use. ISDN has largely been replaced with digital subscriber line (DSL) systems of much higher performance.
Telecommunications in the United Kingdom have evolved from the early days of the telegraph to modern broadband and mobile phone networks with Internet services.
Telephony is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone.
V5 is a family of telephone network protocols defined by ETSI which allow communications between the telephone exchange, also known in the specifications as the local exchange (LE), and the local loop. With potentially thousands of subscribers connected to the LE there is the problem of physically managing thousands of wires out to the local subscribers. Prior to the specification of V5 the manufacturers of exchange equipment had proprietary solutions to the problem. These solutions did not inter-operate and meant being tied into a single manufacturer's method at each exchange.
Telecommunications in Iceland is a diversified market. Iceland has a highly developed telecommunications sector with modern infrastructure. Multiple wholesale and retail providers are operated in a competitive market. As of 2024, Icelands telecom infrastructure is fully digitised and mostly fibre based, with 93% of households having full-fibre availability. Landlines are based on VoIP technology. Mobile telecoms in Iceland adheres to the GSM standard and 2G, 3G, 4G and 5G services are available, as well as a TETRA network for emergency communications. Iceland is connected by 4 submarine cables to both Europe and North America. Broadcasting is based on DVB-T2 standard for television and FM for radio. There are a few printed newpapers, although most mass-media is consumed online. Postal service is provided under universal obligation by the state-owned Iceland Post, but other private postal companies also operate.
Plain Old Telephone Service (POTS), or Plain Ordinary Telephone System, is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. Originally POTS stood for Post Office Telephone Service as early phone lines in most parts of the world were operated directly by the local Post Office.
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. It provides infrastructure and services for public telephony. The PSTN consists 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.
A leased line is a private telecommunications circuit between two or more locations provided according to a commercial contract. It is sometimes also known as a private circuit, and as a data line in the UK. Typically, leased lines are used by businesses to connect geographically distant offices.
In analog telephony, a telephone hybrid is the component at the ends of a subscriber line of the public switched telephone network (PSTN) that converts between two-wire and four-wire forms of bidirectional audio paths. When used in broadcast facilities to enable the airing of telephone callers, the broadcast-quality telephone hybrid is known as a broadcast telephone hybrid or telephone balance unit.
A business telephone system is a telephone system typically used in business environments, encompassing the range of technology from the key telephone system (KTS) to the private branch exchange (PBX).
A landline is a telephone connection that uses metal wires from the owner's premises also referred to as: POTS, Twisted pair, telephone line or public switched telephone network (PSTN).
A naked DSL, also known as standalone or dry loop DSL, is a digital subscriber line (DSL) without a PSTN service — or the associated dial tone. In other words, only a standalone DSL Internet service is provided on the local loop.
The 21st Century Network (21CN) programme is the data and voice network transformation project, under way since 2004, of the UK telecommunications company BT Group plc. It was intended to move BT's telephone network from the AXE/System X Public Switched Telephone Network (PSTN) to an Internet Protocol (IP) system. As well as switching over the PSTN, BT planned to deliver many additional services over their new data network, such as on-demand interactive TV services.
The next-generation network (NGN) is a body of key architectural changes in telecommunication core and access networks. The general idea behind the NGN is that one network transports all information and services by encapsulating these into IP packets, similar to those used on the Internet. NGNs are commonly built around the Internet Protocol, and therefore the term all IP is also sometimes used to describe the transformation of formerly telephone-centric networks toward NGN.
In telecommunication, a two-wire circuit is characterized by supporting transmission in two directions simultaneously, as opposed to four-wire circuits, which have separate pairs for transmit and receive. The subscriber local loop from the telco central office are almost all two wire for analog baseband voice calls, and converted to four-wire at the line card back when telephone switching was performed on baseband audio. Today the audio is digitized and processed completely in the digital domain upstream from the local loop.
System Y is the terminology used by BT, the main operator of the telephone network in the United Kingdom, to refer to the Ericsson AXE digital switching system.
The BT Versatility is a telephone PBX switchboard sold by BT and targeted at small businesses. It is manufactured by Taratel Communications previously Lake Communications in Ireland as the OfficeLink. In South Africa it was sold by Tellumat as the Convergence 30 or C30, in Australia it was sold as the Commander Connect, in the USA it was sold by Inter-tel as the Encore CX and by Mitel as the Mitel 3000
Wholesale line rental (WLR) is a service in which a telecommunications operator takes control of all the connections made through a telephone line from the native operator and collects the subscription fee from the subscribers.
British telephone sockets were introduced in their current plug and socket form on 19 November 1981 by British Telecom to allow subscribers to connect their own telephones. The connectors are specified in British Standard BS 6312. Electrical characteristics of the telephone interface are specified by individual network operators, e.g. in British Telecom's SIN 351. Electrical characteristics required of British telephones used to be specified in BS 6305.
A managed facilities-based voice network (MFVN) is a communications network managed, operated, and maintained by a voice service provider that delivers traditional telephone service via a loop start analog telephone interface. MFVNs are interconnected with the public switched telephone network (PSTN) or other MFVNs and provide dialtone to end users. Historically, this was provided by equipment at Bell company central offices, however today's MFVNs can include a combination of access network, battery-backed customer premises equipment (CPE), network switches and routers, network management systems, voice call servers, and gateways to the broader PSTN.