Telephone numbers in the United Kingdom

+440141dialling code
Telephone numbers in the United Kingdom are administered by the UK government's Office of Communications (Ofcom). For this purpose Ofcom established a telephone numbering plan, known as the National Telephone Numbering Plan, which is the system for assigning telephone numbers to subscriber stations. The numbers are of variable length. Local numbers are supported from land-lines, or numbers can be dialled with a '0'-lead prefix that denotes either a geographical region or another service. Cell phone numbers have their own prefixes which are not geographical and are completely portable between providers.

Trunk prefix

trunk codeTrunk access code8
Calling inter-area (within Australia) (e.g. from Western Australia—area code 8), a caller need not dial an international trunk prefix or a country code. However, the caller must at least dial the Australian trunk prefix (0) followed by the area code (7) and then the local subscriber number: 07 3333 3333. Calling from within the Queensland (7) area, a caller need only dial the telephone number: 3333 3333. However, since the early 21st century, the majority of telephone systems worldwide are able to recognize the area of origin of the call, its direction and destination in order to facilitate communication faster.

Local number portability

number portabilityportported
In the United Kingdom, Ofcom directs fixed-line telephone network providers, mobile phone providers and broadband service providers to provide number portability under the Porting Authorisation Code rules and Migration Authorisation Code code of practice respectively. As the UK is an EU member country, the Ofcom direction is intended to reflect the requirements of EU Directive 2002/22/EU. The number portability service on public telephone networks at a fixed location is available as of 1 April 2014. In Israel, number portability is free and takes 15 minutes. All cellular lines can be ported, Landline numbers may be ported, except between regions (area codes).

Internet access

broadband internetbroadband Internet accessbroadband
Mobile broadband is the marketing term for wireless Internet access delivered through mobile phone towers to computers, mobile phones (called "cell phones" in North America and South Africa, and "hand phones" in Asia), and other digital devices using portable modems. Some mobile services allow more than one device to be connected to the Internet using a single cellular connection using a process called tethering. The modem may be built into laptop computers, tablets, mobile phones, and other devices, added to some devices using PC cards, USB modems, and USB sticks or dongles, or separate wireless modems can be used.


transistorstransistorizedsilicon transistor
From mobile phones to televisions, vast numbers of products include amplifiers for sound reproduction, radio transmission, and signal processing. The first discrete-transistor audio amplifiers barely supplied a few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved. Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive. Before transistors were developed, vacuum (electron) tubes (or in the UK "thermionic valves" or just "valves") were the main active components in electronic equipment.

Network switching subsystem

HLRHome Location RegisterMobile Switching Center
Network switching subsystem (NSS) (or GSM core network) is the component of a GSM system that carries out call out and mobility management functions for mobile phones roaming on the network of base stations. It is owned and deployed by mobile phone operators and allows mobile devices to communicate with each other and telephones in the wider public switched telephone network (PSTN). The architecture contains specific features and functions which are needed because the phones are not fixed in one location. The NSS originally consisted of the circuit-switched core network, used for traditional GSM services such as voice calls, SMS, and circuit switched data calls.

List of Fonejacker episodes

Complete Series 1
The following is an episode list for the E4 series Fonejacker. The series premiered on Comedy Lab with a pilot episode, and due to much popularity, a full series started on 5 July 2007, although the series was originally going to be aired in April at some point, but was delayed. A Christmas special was aired on 20 December of the same year. Then, in 2008, a second series began on 18 September. Both series have been released on DVD including special features such as Unseen Material and audio commentaries. Each episode is approximately 23 minutes long.

Operator Toll Dialing

Nationwide Operator Toll Dialing
Operator Toll Dialing was a project and method used by the Bell System in the USA and Canada to automate the switching and billing of long distance calls in the public switched telephone network (PSTN). The program was initiated by 1945, at which time ca. 5% of the 2.7 million toll board calls per day were handled by this method. Operator Toll Dialing eliminated the need for intermediate and inward operators to complete toll calls to distant central offices. Initially this system involved step-by-step routings to set up each circuit, but later was improved by the development of area codes with machine translation which helped to standardize dialing across the network.

List of international call prefixes

International Call Prefixinternational access code+
Finland, in addition to the standard prefix 00 for default carrier (see Telephone numbering in Finland). 990 – Telia Finland Oyj. 991 – Elisa Oyj. 99511 – Nettia Oy. 99533 – DNA Oy. 99555 – DNA Oy. 99559 – Elisa Oyj. 99577 – DNA Oy. 99588 – Globetel. 99599 - Nettia Oy. 999 – Elisa Oyj. List of country calling codes. List of mobile phone number series by country. List of North American Numbering Plan area codes. Public switched telephone network. Standards and recommendations. List of International Call Prefixes.

Multi-frequency signaling

In-band signaling fell into disfavor in the public switched telephone network (PSTN) as electronic switching systems displaced electro-mechanical switching systems, but legacy offices may still exist, such as in Russia and Italy, that are still using some electromechanical and other legacy switching equipment in the PSTN. Out-of-band Common Channel Signaling (CCS) became nearly universal by the end of the 20th century in the United States. Benefits include higher connection establishment rate and better fraud security.

Soundboard (computer program)

Many free soundboards to make prank phone calls. Thousands of free soundboards.

List of confidence tricks

grandparent scambig storebig stores
A similar caller ID spoofing scheme exists with misleading telephone calls ("vishing") facilitated by Internet telephony. A fraudster can make calls through an Internet-PSTN gateway to impersonate banks, police, schools or other trusted entities. A random dialer computer or auto-dialer can impersonate healthcare providers to get Social Security numbers and birthdates from elderly patients recently released from the hospital. The auto-dialer call states it is from a reputable hospital or a pharmacy and the message explains the need to "update records" to be from the hospital or a pharmacy.

Area code 600

. * Telephone numbers in Canada Non-geographic Telephone Codes for North America. CSCN Assignment Guidelines: Service Area Code (SAC) 600 NXX Code Assignment (April 13, 1994). Archived archived from original on August 28, 2006 via Wayback Machine. Retrieved September 7, 2019.


Microsoft telephone number formatMicrosoft's canonical address format
If there is a need to indicate in-dialing capability of the telephone number, a number of dots corresponding to the length of the extension number can be added at the end. Microsoft canonical address format for telephone numbers derives from E.123 international notation by allowing explicit indication of area code with parentheses. The canonical format is used by the Telephony API (TAPI), a Windows programming interface for dial-up fax, modem, and telephone equipment.

Area codes 919 and 984

919984919, 984
In 1993, the western and southern portions of the numbering plan area were split off to form area code 910. In 1998, the northeastern portion was split off to form area code 252. Area code 919 was initially slated for overlay with area code 984 in 2001. However, the overlay was deferred when the supply of numbers was deemed sufficient for the near term. Within a decade, however, the proliferation of cell phones and pagers meant that the implementation of 984 could no longer be delayed. In September 2011, the North Carolina Utilities Commission announced that the 984 area code was being pressed into service.

Cable modem

cablecable modemscable internet
The earliest systems used the public switched telephone network (PSTN) for the return path since very few cable systems were bi-directional. Later systems used CATV for the upstream as well as the downstream path. Hybrid's system architecture is used for most cable modem systems today. LANcity was an early pioneer in cable modems, developing a proprietary system that was widely deployed in the U.S. LANcity, which was led by the Iranian-American engineer Rouzbeh Yassini, was then acquired by Bay Networks. Bay Networks was subsequently acquired by Nortel. Nortel at the time had formed a joint-venture with Antec called ARRIS Interactive.

Quality of service

QoSquality-of-serviceQuality of Service (QoS)
Commercial VoIP services are often competitive with traditional telephone service in terms of call quality even without QoS mechanisms in use on the user's connection to their ISP and the VoIP provider's connection to a different ISP. Under high load conditions, however, VoIP may degrade to cell-phone quality or worse. The mathematics of packet traffic indicate that network requires just 60% more raw capacity under conservative assumptions. Unlike single-owner networks, the Internet is a series of exchange points interconnecting private networks. Hence the Internet's core is owned and managed by a number of different network service providers, not a single entity.

Routing in the PSTN

routingDynamic Alternative Routingalternate route
Routing in the PSTN is the process used to route telephone calls across the public switched telephone network. Telephone calls are routed across a network of potentially many switching systems, often owned by different telephone carriers. Switching systems are connected with trunks. Each switch may have many neighbors. Neighboring switches owned by different operators are connected at interconnect points. The PSTN is not a full mesh network with the nodes of every operator directly connected to those of every other, which would be impractical and inefficient. Therefore, calls may be routed through intermediate operator networks before they reach their final destination.

Electronic switching system

switching systemselectronic switchingdigital exchange telecommunications system
The adoption of metal–oxide–semiconductor (MOS) and pulse-code modulation (PCM) technologies in the 1970s led to the transition from analog to digital telephony. Later electronic switching systems implemented the digital representation of the electrical audio signals on subscriber loops by digitizing the analog signals and processing the resulting data for transmission between central offices. Time-division multiplexing (TDM) technology permitted the simultaneous transmission of multiple telephone calls on a single wire connection between central offices or other electronic switches, resulting in dramatic capacity improvements of the telephone network.

Springfield (The Simpsons)

SpringfieldMoe's TavernSpringfield Elementary School
Burns believes in order to operate a telephone, you spell the requested person's name out using the alphabetic keypad (he spells out S-M-I-T-H-E-R-S), he is instead connected to Moe's Tavern. As a result, if one was to spell Smithers name out on a telephone keypad, the fictional phone number minus the area code for the tavern would be revealed as 764-8437(7). Moe and his tavern had been the victim of Bart's ongoing prank calls in the earlier seasons when Bart would call looking for nonexistent people with names that would get Moe laughed at by his customers. Though there was one name that backfired on Bart when he asked for Hugh Jass, who had been sitting in the tavern.

Speech recognition

voice recognitionautomatic speech recognitionvoice command
Each word, or (for more general speech recognition systems), each phoneme, will have a different output distribution; a hidden Markov model for a sequence of words or phonemes is made by concatenating the individual trained hidden Markov models for the separate words and phonemes. Described above are the core elements of the most common, HMM-based approach to speech recognition. Modern speech recognition systems use various combinations of a number of standard techniques in order to improve results over the basic approach described above.

Speech coding

speech encodingspeech codecSpeech
Mobile phone. Pulse-code modulation. Psychoacoustic model. Speech interface guideline. Speech processing. Speech synthesis. Telecommunication. Vector quantization. Vocoder. Various Speech Coding Links. ITU-T Test Signals for Telecommunication Systems Test Samples. ITU-T Perceptual evaluation of speech quality (PESQ) tool Sources.

Plain old telephone service

POTSLocal Telephone Servicetelephone
In most cases, the function of the local loop presented to the customer for connection to telephone equipment is practically unchanged and remains compatible with pulse dialing telephones. Due to the wide availability of traditional telephone services, new forms of communications devices such as modems and facsimile machines were initially designed to use traditional analog telephony to transmit digital information. Although POTS provides limited features, low bandwidth, and no mobile capabilities, it provides greater reliability than other telephony systems (mobile phone, VoIP, etc.).


The Burning man test successfully connected about 120 phone calls to 95 different numbers in area codes over North America. At the 2009 Burning Man festival, a larger test setup was run using a 3-sector system. For the 2010 festival, an even larger 2-sector 3-carrier system was tested. At the 2011 festival, the OpenBTS project set up a 3-site network with VSAT gateway and worked in conjunction with the Voice over IP services company Voxeo to provide much of the off-site call routing. RELIEF is a series of disaster response exercises managed by the Naval Postgraduate School in California, USA.


In telephony, a customer's telephone line now typically ends at the remote concentrator box, where it is multiplexed along with other telephone lines for that neighborhood or other similar area. The multiplexed signal is then carried to the central switching office on significantly fewer wires and for much further distances than a customer's line can practically go. This is likewise also true for digital subscriber lines (DSL). Fiber in the loop (FITL) is a common method of multiplexing, which uses optical fiber as the backbone. It not only connects POTS phone lines with the rest of the PSTN, but also replaces DSL by connecting directly to Ethernet wired into the home.