North American Numbering Plan

Area codeArea codes<span style="white-space:nowrap;">Area code(s)
The NANP divides the territories of its members into numbering plan areas (NPAs) which are encoded numerically with a three-digit telephone number prefix, commonly called the area code. Each telephone is assigned a seven-digit telephone number unique only within its respective plan area. The telephone number consists of a three-digit central office code and a four-digit station number. The combination of an area code and the telephone number serves as a destination routing address in the public switched telephone network (PSTN). For international call routing, the NANP has been assigned the international calling code 1 by the International Telecommunications Union (ITU).

Telephone number

telephone numberphone numbertelephone numbers
A telephone number is a sequence of digits assigned to a fixed-line telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN) or other public and private networks. A telephone number serves as an address for switching telephone calls using a system of destination code routing. Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange.


Hand-held mobile phones were introduced for personal service starting in 1973. By the late 1970s, several mobile telephone networks operated around the world. In 1983, the Advanced Mobile Phone System (AMPS) was launched, offering a standardized technology providing portability for users far beyond the personal residence or office. These analog cellular system evolved into digital networks with better security, greater capacity, better regional coverage and lower cost. Today, the worldwide public switched telephone network, with its hierarchical system of many switching centers, can connect any telephone on the network with any other.

Telephone call

telephone callcallphone call
Calls may be placed through a public network (such as the Public Switched Telephone Network) provided by a commercial telephone company or a private network called a PBX. In most cases a private network is connected to the public network in order to allow PBX users to dial the outside world. Incoming calls to a private network arrive at the PBX in two ways: either directly to a users phone using a DDI number or indirectly via a receptionist who will answer the call first and then manually put the caller through to the desired user on the PBX.

VoIP phone

IP PhoneIP phonesEthernet-based phone
A VoIP phone or IP phone uses voice over IP technologies for placing and transmitting telephone calls over an IP network, such as the Internet, instead of the traditional public switched telephone network (PSTN). Digital IP-based telephone service uses control protocols such as the Session Initiation Protocol (SIP), Skinny Client Control Protocol (SCCP) or various other proprietary protocols. VoIP phones can be simple software-based softphones or purpose-built hardware devices that appear much like an ordinary telephone or a cordless phone. Traditional PSTN phones are used as VoIP phones with analog telephone adapters (ATA).

Wireless home phone

wireless home phone
A wireless home phone service is a service that allows a regular wired telephone to connect to a cellular network, as if it were a mobile phone. It is an example of a wireless last mile connection to the public switched telephone network, also known as a wireless local loop. A small device, about the size of a home wireless router, contains the necessary electronics which allow plain old telephone service to be provided to one or two telephone jacks on the back of the unit, as well as having a small radio antenna and a transceiver for the wireless side of the connection. LED indicator lights on the front typically show signal strength and voicemail messages waiting.


9-1-1911911 call
With regard to mobile phones, the rules require carriers to connect 9-1-1 calls from any mobile phone, regardless of whether that phone is currently active. Similar rules for inactive telephones apply in Canada. When a cellular phone is deactivated, the phone number is often recycled to a new user, or to a new phone for the same user. The deactivated cell phone will still complete a 9-1-1 call (if it has battery power) but the 9-1-1 dispatcher will see a specialized number indicating the cell phone has been deactivated. It is usually represented with an area code of (911)-xxx-xxxx. If the call is disconnected, the 9-1-1 dispatcher will not be able to connect to the original caller.

Google Voice

Google VoiceGrand Central
* Level 3 Communications * Global Crossing * Broadvox Communications * * Pac-West Telecom * IBasis for international outbound call routing * Neustar * * Burner (mobile application) * Caller ID spoofing * Comparison of VoIP software * Level 3 Communications * Public switched telephone network * PrivatePhone * Traffic pumping

Index of telephone-related articles

old telephone service (POTS) * Private branch exchange * Public switched telephone network * Satellite phone * Sidetone * Telecommunications * Telephone * Telephone call * Telephone directory * Telephone exchange * Telephone line * Telephone newspaper * Telephone number * Telephone switchboard * Telephone tapping * Telephony * Thomas Edison * Timeline of the telephone * Tip and ring (Wiring terminology) * Toll-free telephone number * 116 telephone number * 800 number * Alexander Graham Bell * Answering machine * Antonio Meucci * Area code * Bell labs * Bell System * Call Login Systems * Carterfone * Cell site * Cellular network * Charles Bourseul * Cordless

Fictitious telephone number

fictitious telephone numberfictional telephone numbersPlaceholder telephone numbers
* 1800 975 711 * 1300 975 707 * 1300 975 708 * 1300 975 709 * 1300 975 710 * 1300 975 711 In Hungary, telephone numbers are in the format 06 + area code + subscriber number, where the area code is a single digit 1 for Budapest, the capital, followed by a seven digit subscriber number, and two digits followed by either seven (for cell phone numbers) or six digits (others). for other areas, cell phone numbers or non-geographic numbers like toll-free or premium-rate numbers.

Mobile radio telephone

mobile radio telephone0Gmanual mobile telephone system
transmission of speech over radio) * Satellite telephone * Mobile Phone History * Mobile Phone Generations *


videoconferencingvideo conferencingvideo chat
The widest deployment of video telephony now occurs in mobile phones. Nearly all mobile phones supporting UMTS networks can work as videophones using their internal cameras, and are able to make video calls wirelessly to other UMTS users in the same country or internationally. As of the second quarter of 2007, there are over 131 million UMTS users (and hence potential videophone users), on 134 networks in 59 countries. Mobile phones can also use broadband wireless Internet, whether through the cell phone network or over a local wifi connection, along with software-based videophone apps to make calls to any video-capable Internet user, whether mobile or fixed.

Caller ID

caller IDcaller line identificationCLI
In the typical telephony environment, a PBX connects to the local service provider through Primary Rate Interface (PRI) trunks. Generally, although not absolutely, the service provider simply passes whatever calling line ID appears on those PRI access trunks transparently across the Public Switched Telephone Network (PSTN). This opens up the opportunity for the PBX administrator to program whatever number they choose in their external phone number fields. Some IP phone services (ITSPs, or Internet Telephony Service Providers) support PSTN gateway installations throughout the world. These gateways egress calls to the local calling area, thus avoiding long distance toll charges.


Most products use methods similar to those used to mitigate SPIT (spam over Internet telephony) and can be broadly categorised by the primary method used. However, due to the complexity of the problem, no single method is sufficiently reliable. Solutions are available as both hardware and software products. Mobile apps are especially prevalent as they use techniques which do not require the modification of infrastructure. Many products are limited to use only on a single medium, such as traditional copper landlines, or mobile phone contracts from a specific mobile phone operator.

Nuisance call

nuisance calltelephone harassmentnuisance calls
* Do-Not-Call list * False alarm * Misdialed call * Pocket dialing * Telephone fraud * Verbal abuse * Do-Not-Call list * False alarm * Misdialed call * Pocket dialing * Telephone fraud * Verbal abuse

Telephone company

telephone companytelecommunications companytelephone companies
) * Communications service provider * History of the telephone * Incumbent local exchange carrier (of the Bell System) * List of telephone operating companies * List of mobile network operators * Mobile network operator * Plain old telephone service (POTS) * Public switched telephone network * Telecommunications Industry Association (for the development of U.S. telecom standards) * Regional Bell Operating Company (in the U.S.) * Service provider * Telecommunications service provider * The Phone Company, free, non-commercial email-to-fax service * Bibliography * Huurdeman, Anton A.

List of North American Numbering Plan area codes

List of North American area codesNPAArea Codes
'' * Bell System * List of country calling codes * Telephone numbers in the Americas * List of future North American area codes * List of original NANP area codes * Bell System * List of country calling codes * Telephone numbers in the Americas * List of future North American area codes * List of original NANP area codes

Denial-of-service attack

denial-of-service attackdenial of servicedistributed denial of service
Widespread publication of a number can also flood it with enough calls to render it unusable, as happened by accident in 1981 with multiple +1-area code-867-5309 subscribers inundated by hundreds of misdialed calls daily in response to the song 867-5309/Jenny. TDoS differs from other telephone harassment (such as prank calls and obscene phone calls) by the number of calls originated; by occupying lines continuously with repeated automated calls, the victim is prevented from making or receiving both routine and emergency telephone calls. Related exploits include SMS flooding attacks and black fax or fax loop transmission.

Directory assistance

directory assistancedirectory enquiries118 500
In mainland China, (area code) 114 is dialed for directory assistance in that area code. In Ethiopia, 8123 is dialed for directory assistance. In Israel, 144 or 1344 is dialed for directory assistance. In the Philippines, 187 is dialed for PLDT and Digitel subscribers. In Taiwan, directory assistance is available by dialing 105 from mobile phones, or by dialing 104 from landline phones. * 555 (telephone number) * Telephone directory *Mark Lawson, The Guardian, 19 March 2005, "Dial 0 for progress" * 1) 411 LDA: Local Directory Assistance. 411 is dialled and the operator is requested to search for a listing in a group of area codes local to the caller (LATA).

Cellular network

cellular networkcellularmobile network
The MSC provides a connection to the public switched telephone network (PSTN). The link from a phone to the RBS is called an uplink while the other way is termed downlink. Radio channels effectively use the transmission medium through the use of the following multiplexing and access schemes: frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and space division multiple access (SDMA).

Telephone exchange

telephone exchangeexchangescentral office
For business and billing purposes, telephony carriers also define rate centers, which in larger cities may be clusters of central offices, to define specified geographical locations for determining distance measurements. In the United States and Canada, the Bell System established in the 1940s a uniform system of identifying central offices with a three-digit central office code, that was used as a prefix to subscriber telephone numbers. All central offices within a larger region, typically aggregated by state, were assigned a common numbering plan area code.


E.164 is an ITU-T recommendation, titled The international public telecommunication numbering plan, that defines a numbering plan for the worldwide public switched telephone network (PSTN) and some other data networks. E.164 defines a general format for international telephone numbers. Plan-conforming numbers are limited to a maximum of 15 digits, including the international call prefix. The presentation of a number is usually prefixed with the plus sign, indicating that the number includes the country calling code.

Signalling System No. 7

SS7SS7 networkCCS7
Signaling System No. 7 (SS7) is a set of telephony signaling protocols developed in 1975, which is used to set up and tear down most of the world's public switched telephone network (PSTN) telephone calls. It also performs number translation, local number portability, prepaid billing, Short Message Service (SMS), and other mass market services. In North America it is often referred to as CCSS7, abbreviated for Common Channel Signaling System 7. In the United Kingdom, it is called C7 (CCITT number 7), number 7 and CCIS7 (Common Channel Interoffice Signaling 7). In Germany, it is often called ZZK-7 (Zentraler ZeichengabeKanal Nummer 7).

Kayvan Novak

In 2005, he and Ed Tracy created Fonejacker, a prank call show as part of Channel 4's Comedy Lab strand. After the pilot, he was given a Christmas special and a six-part series, which began airing on 5 July 2007 on E4 and 7 September 2007 on Channel 4. In November 2009, he appeared on the Channel 4 show The Increasingly Poor Decisions of Todd Margaret, playing a bomb disposal officer. In April 2010, Novak began appearing in a spin-off of Fonejacker called Facejacker, in which he adopted various disguises, including several characters heard in Fonejacker.

Business telephone system

PBXprivate branch exchangekey telephone system
The central office lines provide connections to the public switched telephone network (PSTN) and the concentration aspect of a PBX permits the shared use of these lines between all stations in the organization. Its intercommunication ability allows two or more stations to directly connect while not using the public switched telephone network. Each PBX-connected device, such as a telephone, a fax machine, or a computer modem, is often referred to as an extension and has a designated extension telephone number that may or may not be mapped automatically to the numbering plan of the central office and the telephone number block allocated to the PBX.