Telephone number

phone numbertelephone numbersphone numbersnumberdirectory numberPhoneMobile device numbermobile numberdestination numberDialing code
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.wikipedia
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Telephone line

phone linelinetelephone cable
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.
This is the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies a single telephone number for billing purposes reserved for that user.


phonetelephonesLocal Telephone Service
In addition to telephones, they have been used to access other devices, such as computer modems, pagers, and fax machines.
In addition, most telephones contain a ringer to announce an incoming telephone call, and a dial or keypad to enter a telephone number when initiating a call to another telephone.

Vertical service code

calling featureservice featureCustom Local Area Signaling Services
Telephone numbers are often dialed in conjunction with other signaling code sequences, such as vertical service codes, to invoke special telephone service features.
Some vertical service codes require dialing of a telephone number after the code sequence.

Telephone numbering plan

Area codeTelephone codearea codes
Telephone numbers are assigned within the framework of a national or regional telephone numbering plan to subscribers by telephone service operators, which may be commercial entities, state-controlled administrations, or other telecommunication industry associations.
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints.

Telephone exchange

exchangescentral officeexchange
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.
For example, one switch might send only the last four or five digits of a telephone number.

Ten-digit dialing

10-digit dialingten-digit diallingten digits
If the area has no area code overlays or if the provider allows it, seven-digit dialing may be permissible for calls within the area, but some areas have implemented mandatory ten-digit dialing.
In the United States and Canada, ten-digit dialing is the practice of including the area code of a telephone number when dialing to initiate a telephone call.

Telephone call

callphone callphone calls
A telephone number serves as an address for switching telephone calls using a system of destination code routing.
Fees depend on the provider of the service, the type of service being used (a call placed from a landline or wired telephone will have one rate, and a call placed from a mobile telephone will have a different rate) and the distance between the calling and the called parties.

List of country calling codes

Country CodeDialing codeCalling code
ITU-T recommendation E.123 describes how to represent an international telephone number in writing or print, starting with a plus sign and the country code.
Country calling codes or country dial-in codes are telephone number prefixes for reaching telephone subscribers in the networks of the member countries or regions of the International Telecommunication Union (ITU).

Request line

contest line
Other special phone numbers are used for high-capacity numbers with several telephone circuits, typically a request line to a radio station where dozens or even hundreds of callers may be trying to call in at once, such as for a contest.
Although only one telephone number is usually announced, major stations typically have line hunting, with the same number being directed to any available one of several lines within the hunt group.

North American Numbering Plan

Area codeArea codesArea code(s)
The format and allocation of local phone numbers are controlled by each nation's respective government, either directly or by sponsored organizations (such as NANPA in the US or CNAC in Canada).
Each telephone is assigned a seven-digit telephone number unique only within its respective plan area.

In the international telephone network, the format of telephone numbers is standardized by ITU-T recommendation E.164.
E.164 defines a general format for international telephone numbers.

List of international call prefixes

International Call Prefixinternational access code+
When calling an international number from a landline phone, the + must be replaced with the international call prefix chosen by the country the call is being made from.
The international dialing prefix must be dialed before the country calling code and the destination telephone number.


Microsoft telephone number formatMicrosoft's canonical address format
ITU-T recommendation E.123 describes how to represent an international telephone number in writing or print, starting with a plus sign and the country code.
It provides guidelines for the presentation of telephone numbers, email addresses, and web addresses in print, on letterheads, and similar purposes.

Local number portability

number portabilityportported
Local number portability (LNP) allows a subscriber to request moving an existing telephone number to another telephone service provider.
Local number portability (LNP) for fixed lines, and full mobile number portability (FMNP) for mobile phone lines, refers to the ability of a "customer of record" of an existing fixed-line or mobile telephone number assigned by a local exchange carrier (LEC) to reassign the number to another carrier ("service provider portability"), move it to another location ("geographic portability"), or change the type of service ("service portability").

Lowell, Massachusetts

LowellLowell, MALowell, Massachusetts, USA
Telephone numbers were first used in 1879 in Lowell, Massachusetts, when they replaced the request for subscriber names by callers connecting to the switchboard operator.

Directory assistance

directory enquiries118 5001-800-555-1212
The "555" prefix was reserved for telephone company use and was only consistently used for directory assistance (information), being "555–1212" for the local area.
In telecommunications, directory assistance or directory enquiries is a phone service used to find out a specific telephone number and/or address of a residence, business, or government entity.

Rate center

rate centre
Number portability usually has geographic limitations, such as an existing local phone company only being able to port to a competitor within the same rate centre.

555 (telephone number)

555555 telephone number5-5-5
The use of numbers starting in 555- (KLondike-5) to represent fictional numbers in U.S. movies, television, and literature originated in this period.
The telephone number prefix 555 is a central office code in the North American Numbering Plan, used as the leading part of a group of 10,000 telephone numbers, 555-XXXX, in each numbering plan area (NPA)(area code).

PEnnsylvania 6-5000

212-736-5000telephone number
According to the hotel's website, PEnnsylvania 6-5000 is New York's oldest continually assigned telephone number and possibly the oldest continuously-assigned number in the world.
PEnnsylvania 6-5000 is a telephone number in New York City, written in the 2L+5N (two letters, five numbers) format that was common in the largest US cities from approximately 1930 into the 1960s.

Director telephone system

Directordirector exchangeDirector system
Until then, only the director areas (Birmingham, Edinburgh, Glasgow, Liverpool, London and Manchester) and the adjacent non-director areas had the lettered dials; the director exchanges used the three-letter, four-number format.
The telephone numbering plan for the Director System assigned seven-digit telephone numbers to subscriber stations.

National conventions for writing telephone numbers

Local conventions for writing telephone numbersTelephone number formats
The presentation of telephone numbers in this article does not include any international dialing codes necessary to route calls via international circuits.

Geographic number

A geographic number is a telephone number, from a range of numbers in the United Kingdom National Telephone Numbering Plan, where part of its digit structure contains geographic significance used for routing calls to the physical location of the network termination point of the subscriber to whom the telephone number has been assigned, or where the network termination point does not relate to the geographic area code but where the tariffing remains consistent with that geographic area code.


Phonewords are mnemonic phrases represented as alphanumeric equivalents of a telephone number.

Short code

Common Short Codeshortcodefive-digit and six-digit numbers, shorter than a telephone number
Short codes, or short numbers, are short digit sequences, significantly shorter than telephone numbers, that are used to address messages in the Multimedia Messaging System (MMS) and short message service (SMS) systems of mobile network operators.

Automatic number announcement circuit

ANAC958-ANACautomatic number announcement
An automatic number announcement circuit (ANAC) is a component of a central office of a telephone company that provides a service to installation and service technicians to determine the telephone number of a line.