North American Numbering Plan
Encyclopedia
The North American Numbering Plan (NANP) is an integrated telephone numbering plan
administered by Neustar (formerly Lockheed Martin IMS
) which encompasses 24 countries and territories, including the United States
and its territories
, Canada
, Bermuda
, and 16 nations of the Caribbean
. The term is also used, by metonymy
, to refer to the geographic area in which that plan has been implemented.
The NANP is a standardized system of numbering plan areas (NPA), which have evolved over time into a system of three-digit area codes and seven-digit telephone number
s. Through this plan, telephone
calls can be directed to particular regions of the larger NANP public switched telephone network (PSTN
), where they are further routed by the local networks.
, the NANP set out to simplify and facilitate direct dialing of long distance calls. Area code 201
was the first implemented under the plan. The NANP initially applied only to the U.S. and Canada, but at the request of the British
Colonial Office
, it was expanded to Bermuda
and the British West Indies
(including Trinidad and Tobago
), because of their historic telecommunications administration through Canada
as parts of the British Empire
- and also their continued associations with Canada, especially during the years of the telegraph and the All Red Line
system.
Despite the "North American" name of the calling plan, not all North American countries participate in NANP. Mexico
, the Central America
n countries and some Caribbean
countries (Cuba
, Haiti
, and the French
and Dutch-speaking Caribbean
, though Dutch-speaking Sint Maarten joined the NANP in September 2011) are not part of the system. The only Spanish-speaking country in this plan is the Dominican Republic
(although Spanish-speaking U.S. commonwealth Puerto Rico is as well). Mexican participation was planned, but implementation stopped after two area codes were put into use (Mexico City
and northwestern Mexico); these ended in 1991 when Mexico withdrew from the NANP.
The NANP is administered by the North American Numbering Plan Administration (NANPA).
Current NANP number format can be summed up via the following:
For example:
The country calling code for the NANP is +1. In international format, an NANP number should be listed thus: +1 301 555 0100 (example using the original area code for Maryland). "1" is also the code often used to make direct-dialed long-distance calls within the NANP.
Each three-digit area code may contain up to 7,919,900 unique phone numbers:
The standard dialing plan in most cases are as follows:
Most areas allow permissive dialing of 10D or 1+10D even for calls that could be dialed as 7D. The number of digits dialed is unrelated to whether a call is local or toll when there is no toll alerting. Allowing 7D local dialing across an area code boundary (which is uncommon today and only possible with toll alerting) requires NXX protection on the other side to avoid dialing conflicts.
Most areas permit local calls to be dialed as 1+10D except for Texas, Georgia, and some jurisdictions in Canada which require that callers know which numbers are local and which are toll, dialing 10D for all local calls and 1+10D for all toll calls.
In almost all cases, operator-assisted calls require dialing 0+10D.
from the US than it does to call the UK or Japan, even though the dialing format is the same as the domestic format. Similarly, calls from Bermuda to US numbers, (including toll-free 1-800
), incur high international rates. This was because many of the island nations at the time implemented a plan of subsidizing the cost of local phone services by directly charging heavier pricing levies on the international Long Distance services.
Because of these higher fees, a handful of scams had taken advantage of customers' unfamiliarity with pricing structure to call the legacy regional area code 809. Some scams lured customers from the U.S. and Canada into placing expensive calls to the Caribbean
, by representing area code 809
as a regular domestic, low-cost, or toll-free call.
These scams are currently on the decline, with many of the Cable and Wireless service monopolies being opened up to competition, hence bringing rates down. Additionally, many Caribbean territories have implemented local government agencies to regulate telecommunications rates of providers.
calls, the NANP was created and instituted in 1947 by AT&T
, also known as the Bell System
, the U.S. telephone semi-monopoly
. At first, the codes were used only by long-distance operators; the first customer-dialed calls using area codes did not occur until November 10, 1951, when the first directly dialed call was made from Englewood
, New Jersey to Alameda
, California. Direct dialing was gradually instituted throughout the country, and by the mid-1960s, it was commonplace in most larger cities.
Originally there were only 86 codes, with the biggest population areas getting the numbers that took the shortest time to dial on rotary telephones. Thus New York City
was given 212, Los Angeles
213, Chicago
312, Dallas 214, Detroit 313, Pittsburgh 412; while four areas received the then-maximum number of 21 clicks: South Dakota
(605), North Carolina
(704), South Carolina
(803), and the Maritime Provinces of Canada (902). Additionally, in the original plan a middle digit of 0 indicated that the area code covered an entire state/province, while area codes with a middle digit of 1 were assigned to jurisdictions that were divided into multiple area codes.
At first, area codes were all in the form NYX, where N is any number 2-9, Y is 0 or 1, and X is any number 1-9 (if Y is 0) or any number 2-9 (if Y is 1). The restriction on N saves 0 for calling the operator, and 1 for signaling a long-distance call. The restriction on the second digit, limiting it to 0 or 1, was designed to help telephone equipment recognize the difference between a three-digit "area code" (with 0 or 1 as the second digit) and the three-digit "exchange" prefix (which had avoided 0 or 1 for the second digit, because of restrictions in existing switching equipment). For example, when a caller dialed "202-555-1212", the switching equipment would recognize that "202" was an area code because of the middle 0, and route the call appropriately. If a caller were to dial 345-6789, the 4 would cause the number to be recognized as a long-distance number within the area and routed as such, without waiting for the caller to finish dialing.
In the late 1980s and early 1990s, NANPA (then still part of Bellcore, which is now Telcordia Technologies
) began to urge and later require all long-distance calls within each area to be prefixed with the digit 1 to distinguish them from local calls, so that badly needed prefixes with 0 or 1 in the middle could be assigned to local telephone exchange
s. Also, since it had nearly run out of area codes using the above formula, it allowed the assignment of area codes using the form N10, such as 210 in the San Antonio
, Texas, area and 410 in eastern Maryland
. Therefore, someone calling from San Jose to Los Angeles before the change would have dialed 213-555-1234 and after the change 1-213-555-1234, which then allowed 213 to be used as an exchange prefix in the San Jose area.
Until 1991, calls to some areas of Mexico
from the United States
and Canada
were made using NANP area codes, but Mexican participation in the NANP was discontinued in favor of the general international format, using country code +52 instead. Area Code 905 (formerly Mexico City) was re-assigned to the Greater Toronto Area
outside of Toronto (which retained Area Code 416), and Area Code 706 (formerly northwest Mexico) was reassigned to northern Georgia
, surrounding the Atlanta region which retained 404.
, modem
, and mobile phone
communications).
The second and more important reason is the telecom deregulation of local telephone service in the US beginning in the early-to-mid 1990s. At that time, the Federal Communications Commission began allowing telecommunication companies to compete with the incumbent local exchange carrier
(usually by forcing the existing monopoly service provider to lease infrastructure to other local providers who then resold the service to consumers). However, because of the original design of the numbering plan and telephone switching network that assumed only a single provider, number allocations had to be made in 10,000-number blocks.
Thus, whenever a new local service provider entered a given market, it would be allocated 10,000 numbers by default, even if the provider only obtained a few customers. As more companies began requesting numbering allocations, this caused many area codes to begin exhausting their supply of available numbers (code "in jeopardy" in telecom jargon), and additional area codes were needed. In reality, many of the new telecom ventures were not successful; while the number of area codes started increasing rapidly, this did not necessarily translate to a much larger number of actual telephone subscribers as large blocks of numbers lay unassigned to any "real" subscribers because of the 10,000-number block allocation requirement. When these telecom ventures were merged or bought or liquidated, their blocks went to the successor or went unused. No regulatory mechanism existed to reclaim and reassign these underutilized blocks.
In general, area codes were added either as "splits" (in which an area code was divided into two or more regions, one retaining the older area code and the other area(s) receiving a new code), or "overlay
s", in which multiple codes are assigned to the same geographical area. Subtle variations of these techniques have been used as well, such as "dedicated overlays", in which the new overlaid code was reserved for a particular type of service, such as cellular phones and pagers (the only true example of this was area code 917 in New York City), and "concentrated overlays", in which a part of the area retained a single code while the rest of the region received an overlay code.
After the remaining valid area codes were used up by expansion, in 1995 the rapid increase in the need for more area codes (both splits and overlays) forced NANPA to allow the digits 2 through 8 to be used as a middle digit in new area code assignments, with 9 being reserved as a "last resort" for potential future expansion. At the same time, local exchanges were allowed to use 1 or 0 as a middle digit. The first area codes without a 1 or 0 as the middle digit were area code 334
in Alabama and area code 360
in Washington, which both began service on January 15, 1995.
Codes ending in double digits are reserved as easily recognizable codes (ERCs), to be used for special purposes such as toll-free 800, 888, 877, 866 and 855, personal 700
numbers, and high-toll 900 numbers, rather than for geographic areas. (Nevada was denied lucky 777 for this reason; it received 775
instead when most of Nevada split from 702
, which continues to serve the Las Vegas area.)
and Canada
had more than one area code, either through splitting the city into different areas (splits) or having more than one code for the same area (overlays). For example, in Manhattan
, subscribers' numbers had the NPA code 212, but two additional codes—first 917 (which initially was exclusively for cellular phones and pagers until that idea was struck down in a Federal court), then 646—were also introduced. This means that the area code must be dialed, even for local calls. In other areas, 10-digit or 11-digit dialing is now required for all local calls. The transition to 10-digit dialing typically starts with a permissive dialing phase in which both 7-digit and 10-digit dialing is optional. During this period, the transition is heavily publicized. After a period of several months, the mandatory dialing phase is introduced, in which 7-digit dialing no longer works. Atlanta was the first US city to have mandatory 10-digit dialing throughout its metropolitan area, roughly coinciding with the 1996 Summer Olympics
held there. Atlanta was used as the test case not only because of its size, but also because it enjoyed the world's largest fiber optic network at the time (five times that of New York
then), and it was home to BellSouth
(now part of AT&T), then the Southeastern Regional Bell Operating Company
.
The overlap between area codes and exchange prefixes has occasionally produced some confusion because the three digits can be the same for both. Nashua
, New Hampshire, for example, has a local exchange that begins with (603) 888, which is also an area code for toll-free calls. If somebody in Nashua means to call 1-888-555-1212 but forgets the initial "1," he or she will actually dial the local number 1-603-888-5551. This, however, is generally not a problem in major metropolitan area
s with overlapping area codes, which were mandated by the FCC
to dial all ten digits for all local calls so as not to give new numbers or telecommunications providers a "disadvantage."
The use of a splitting instead of an overlay generally avoids the requirement for mandatory area-code dialing, but at the expense of having to convert some of the numbers to the new code. In addition to the requirements of updating records and directories to accommodate the new numbers, for efficient conversion this requires a period of "permissive dialing" in which the new and old codes are both allowed to work. Also, many splittings involved significant technical issues, especially when the area splittings occurred over boundaries other than phone network divisions.
As an extreme example of an area code splitting gone somewhat awry, in 1998 area code 612
, which had covered the Minneapolis – Saint Paul Twin Cities, was split to create area code 651
for St. Paul
and the eastern metropolitan area. The Minnesota Public Utilities Commission
mandated that the new boundary exactly follow municipal boundaries (which were distinctly different from telephone exchange boundaries), and that all subscribers keep their 7-digit numbers. These two goals were directly at odds with the reason for the split (to generate additional phone numbers), and there were more than 40 exchanges whose territory straddled the new boundary. The result was prefixes duplicated in both area codes, which counteracted much of the benefit of the splitting, with only 200 of 700 prefixes in area 612 moving entirely to area 651. As a result, in less than two years area code 612 again exhausted its supply of phone numbers, and it underwent another three-way split in 2000, creating the new area codes 763
and 952
. Again, the split followed political boundaries rather than rate center boundaries, resulting in additional split prefixes; a few numbers moved from 612 to 651 and then to 763 in less than two years.
) to look for a way to alleviate the numbering shortage. As a result a new program called "number pooling" was piloted in 2001, which allowed allocating numbers in blocks of 1,000 rather than 10,000. Because of the design of the switched telephone network, this was a considerable technical challenge and was carried out together with another technically challenging program, local number portability
. Since then the program has been rolled out to most parts of the United States and, together with aggressive reclamation of unused number blocks from telecom providers, has reduced the need for additional area codes, so much so that many previously designated area splits and overlays have been postponed indefinitely.
and, in Europe, E.161
). This accommodates 24 letters. Historically, the letters Q and Z were omitted, though on some modern telephones they are added, so that the alphabet is apportioned as follows:
2 = ABC
3 = DEF
4 = GHI
5 = JKL
6 = MNO
7 = PRS or PQRS
8 = TUV
9 = WXY or WYZ or WXYZ
No letters are allocated to the 1 or 0 keys (although some corporate voicemail
systems are set up to count Q and Z as 1, and some old telephones assigned the Z to the digit 0).
Originally, this scheme was meant as a mnemonic device for telephone number prefixes. When telephone numbers in the US were standardized in the mid-20th century, they were made seven digits long, with the first two digits, the prefix, expressed as letters rather than numbers. (Before World War II
, a few localities used three letters and four numbers; in most cities with customer dialing, phone numbers had only six digits — two letters followed by four numbers.) The prefix was a name, and the first two or three letters (usually shown in capitals) of the name were dialed. Later, the third letter (where previously used) was replaced by a number, or an extra number was added; this generally happened after World War II, although New York City
did this in 1930. Thus, the famous Glenn Miller
tune "PEnnsylvania 6-5000
" refers to a telephone number 736-5000, the number of the Hotel Pennsylvania
, which still bears the same number today. Similarly, the classic film "BUtterfield 8
" is set in the East Side of Manhattan
between roughly 64th and 86th Streets, where the telephone prefixes include 288. This is why, in some works of fiction, phone numbers will begin with "KLondike 5" or "KLamath 5", which translates to 555, an exchange that is unused in most areas.
The letter system was phased out, beginning before 1965 (though it persisted ten years later in some places, and was included in Bell of Pennsylvania
directories until 1983), but alphabetic dialing remains as a commercial mnemonic
gimmick, particularly for toll-free numbers. For example, one can dial 1-800-FLOWERS
to send flowers to someone, or 1-800-DENTIST to find a local dentist. Sometimes, longer phoneword
s are used — for example one might be invited to give money to a public radio station by dialing 1-866-KPBS-GIVE. The "number" is 8 digits long, but only the first seven need be dialed. If an eighth (or more) digit is dialed, the switching system will ignore it. Mobile users may need to manually drop any numbers past the seventh digit as some mobile switching systems will not automatically ignore them, resulting in a failed call. Also, users of smartphone
s including BlackBerry
devices can have difficulty dialing phonewords, as some of those devices do not have the apportioned letters on the keys used for dialing. This can be avoided by accompanying the use of phonewords with the actual numeric phone number, allowing users of such smartphones to dial using the numeric phone number.
In addition to commercial uses, alphabetic dialing has occasionally influenced the choice of regional area codes in the United States. For example, when area 423
(East Tennessee
) was split in 1999, the region surrounding Knoxville
was assigned area code 865
, chosen to represent the word "VOL"—short for "Volunteers", the nickname of athletic teams at the University of Tennessee
.
The state of Nevada has previously attempted to obtain area code 777 (lucky 7's), but was unable to secure it.
See Telephone number
s
in Canada, no separate, non-geographical area codes have been created for cellular phones, as is the case in most European and Asian countries, where mobile services are assigned their own prefixes. This means that most North American mobile phones are assigned the same locality-specific codes as landlines, and calls to them are billed at the same rate. Consequently, the "caller pays" pricing model adopted in other countries, in which calls to cellular phones are charged at a higher nationwide rate but receiving calls is free, could not be used. Instead, North American cellular telephone users are also generally charged to receive calls as well ("subscriber pays"). In the past, this discouraged mobile users from using the phones or giving out the number. However, robust price competition among carriers has led to dramatic cuts in the average price per minute for contract customers (for both inbound and outbound calls), which can compare favorably to those in caller-pays countries. Most users select bundle pricing plans that include all the minutes they expect to use in a month. Many carriers also offer free calling between mobile phones on the carrier's network, and some also offer free calling to a list of user-selected phone numbers (which can include both cell phones and landlines).
Some industry observers have blamed "subscriber pays" as one of the main factors in the relatively low mobile phone penetration rate
in the United States compared to that of Europe. In this model the convenience of the mobility is charged to the subscriber. Callers from outside the local-calling region of the assigned number, however, pay for a long-distance call, although domestic long distance rates are generally lower than the rates in caller-pays systems. Conversely, an advantage of caller-pays is the relative absence of telemarketing
and nuisance call
s to mobile numbers. The integrated numbering plan also enables local number portability
between fixed and wireless services within a region, allowing users to switch to mobile service while keeping their phone number.
The initial plan for overlays did allow for providing separate area codes for use by mobile phones, faxes, pagers, etc., although these were still assigned to a specific geographical area, rather than the nationwide mobile area codes common to most other countries, and were charged at the same rate as other area codes. Initially, the new area code 917 for New York City
was specifically assigned for this purpose within the 5 boroughs; however, a Federal court struck this down and banned the use of an area code for a specific telephony purpose. Since mobile telephony is expanding faster than landline, new area codes typically have a disproportionately large fraction of mobile numbers, although landline and other services rapidly follow and local network portability can blur these distinctions.
The experience of Hurricane Katrina
and similar events revealed a possible disadvantage of the methods employed in the geographic assignment of cellular numbers. Many mobile phone users could not be reached, their phones rendered inoperable, even when they were far from the stricken areas, because the routing of calls to their phones depended on equipment in the affected area.
Another related issue for services like mobile telephony is the scarcity of telephone numbers. In contrast to other countries, where mobile and other special-number operators enjoy wide leeway to generate large numbers of telephone numbers, this is not an option in the NANP, with its geographical area codes with a fixed number of digits.
and the U.S. Virgin Islands
, shared the NPA code 809, but they are now able to have separate codes. Code (809)
is now only used by the Dominican Republic
. In 1997 the United States Pacific Territories of the Northern Mariana Islands
and Guam
became part of the NANP, as did American Samoa
in October 2004. The Dutch
possession of Sint Maarten was originally scheduled to join the NANP on May 31, 2010, but the changeover was postponed to September 30, 2011.
Bermuda:
Puerto Rico:
US Virgin Islands:
Northern Marianas:
Guam:
American Samoa:
Sint Maarten:
See also: Split from the 809 Area code
television
shows and film
s, 555 (or, in older movies and shows, KLondike 5 or KLamath 5) is used as the first three digits of fictional telephone number
s, so if anyone is tempted to telephone a number seen on screen, it does not cause a nuisance to any actual person.
There are occasions, however, when a non-555 is used in real-life context (often in songs), with varying intents and consequences.
Similarly, not all numbers beginning with "555" are fictional. For example, 555-1212 is the number for directory assistance
in many places. In many, but not all areas, dialing "555" numbers other than 555-1212 will actually get you to directory assistance as well. In fact, only 555-0100 through 555-0199 are now reserved for fictional use, with the other numbers having been released for assignment. Since "1xx" exchanges are generally not assigned, some movies have started to use fictional telephone numbers starting with "1".
, which will probably face the task of adding one or two digits to each number, likely sometime after 2038. During that time, all public and private phone systems within the NANP area will have to be upgraded and reprogrammed (or even replaced) to recognize the new dialing rules.
One plan being considered adds a 1 or 0 either to the beginning or end of the area code, or the beginning of the local 7-digit number (or both), which will require mandatory 11-digit dialing (even for local calls), between any two NANP numbers, well before the transition period. In another proposal, existing codes would be changed to "x9xx" (e.g. San Francisco's 415 would become 4915); once that conversion is complete, the new second digit would be opened for a new range. (Compare PhONE Day in the United Kingdom
, which added a "1" to the beginning of area codes in preparation for later using other digits, such as "2", for new area codes.) Other proposals include reallocating blocks of numbers assigned to smaller long distance carriers or unused reserved services.
NANPA previously coordinated an expansion of long-distance carrier
access ("dial-around") codes from five digits (such as 10-321) to seven (10-10-321), in 1998. Vertical service code
s, such as *69 (callback
) and *70 (suspend call waiting
), have been designed to allow the use of both two- and three-digit codes.
There are also special codes
, such as:
Note: The four digit numbers do not work in some areas. The codes prefixed with the "*" symbol are intended for use on Touch-Tone telephone
s, whereas the four-digit numbers prefixed 11xx are intended for use on older rotary dial telephones, where the Touch-Tone * symbol is not available.
Not all NANPA countries use the same codes. For example, the emergency telephone number
is not always 911: Trinidad and Tobago
and Dominica
uses 999
, as in the United Kingdom
. The country of Barbados
uses 211 for police force
, 311 for fire
, and 511 for ambulance
, while Jamaica
uses 114 for directory assistance, 119 for police force
, and 110 for fire
and ambulance
services.
Despite its early importance as a share of the worldwide telephone system, few of the NANP's codes, such as 911, have been adopted outside the system. Determining that 911 requires unnecessary rotation time on rotary dial telephones, the European Union
has adopted its own standardized number of 112
, while countries in Asia and the rest of the world use a variety of other two- or three-digit emergency telephone number
combinations. The 112 code is gaining prevalence because of its preprogrammed presence in mobile telephones that conform to the European GSM standard. The European Union and many other countries have chosen the International Telecommunication Union
's 00 as their international access number instead of 011. The toll-free prefix 800 has been widely adopted elsewhere, including as the international toll-free country code. It is often preceded by a 0 rather than a 1 in many countries where 0 is the trunk prefix
.
Telephone numbering plan
A telephone numbering plan is a type of numbering scheme used in telecommunications to allocate telephone numbers to subscribers and to route telephone calls in a telephone network. A closed numbering plan, such as found in North America, imposes a fixed total length to numbers...
administered by Neustar (formerly Lockheed Martin IMS
Lockheed Martin
Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....
) which encompasses 24 countries and territories, including the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and its territories
Insular area
An insular area is a United States territory, that is neither a part of one of the fifty U.S. states nor the District of Columbia, the federal district of the United States...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
, and 16 nations of the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
. The term is also used, by metonymy
Metonymy
Metonymy is a figure of speech used in rhetoric in which a thing or concept is not called by its own name, but by the name of something intimately associated with that thing or concept...
, to refer to the geographic area in which that plan has been implemented.
The NANP is a standardized system of numbering plan areas (NPA), which have evolved over time into a system of three-digit area codes and seven-digit telephone number
Telephone number
A telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...
s. Through this plan, telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...
calls can be directed to particular regions of the larger NANP public switched telephone network (PSTN
Public switched telephone network
The public switched telephone network is the network of the world's public circuit-switched telephone networks. It consists of telephone lines, fiber optic cables, microwave transmission links, cellular networks, communications satellites, and undersea telephone cables, all inter-connected by...
), where they are further routed by the local networks.
Current system
Developed in the 1940's, and first implemented in 1951 by AT&TAT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
, the NANP set out to simplify and facilitate direct dialing of long distance calls. Area code 201
Area code 201
201 is the North American telephone area code for the state of New Jersey covering most of Bergen County, as well as parts of Essex, Hudson and Passaic. It is overlaid with area code 551....
was the first implemented under the plan. The NANP initially applied only to the U.S. and Canada, but at the request of the British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
Colonial Office
Colonial Office
Colonial Office is the government agency which serves to oversee and supervise their colony* Colonial Office - The British Government department* Office of Insular Affairs - the American government agency* Reichskolonialamt - the German Colonial Office...
, it was expanded to Bermuda
Bermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
and the British West Indies
British West Indies
The British West Indies was a term used to describe the islands in and around the Caribbean that were part of the British Empire The term was sometimes used to include British Honduras and British Guiana, even though these territories are not geographically part of the Caribbean...
(including Trinidad and Tobago
Trinidad and Tobago
Trinidad and Tobago officially the Republic of Trinidad and Tobago is an archipelagic state in the southern Caribbean, lying just off the coast of northeastern Venezuela and south of Grenada in the Lesser Antilles...
), because of their historic telecommunications administration through Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
as parts of the British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...
- and also their continued associations with Canada, especially during the years of the telegraph and the All Red Line
All Red Line
The All Red Line was an informal name for the system of electrical telegraphs that linked much of the British Empire.It was inaugurated on 31 October 1902. It had this name because on many political maps, British Empire territory was coloured red ....
system.
Despite the "North American" name of the calling plan, not all North American countries participate in NANP. Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, the Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
n countries and some Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
countries (Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
, Haiti
Haiti
Haiti , officially the Republic of Haiti , is a Caribbean country. It occupies the western, smaller portion of the island of Hispaniola, in the Greater Antillean archipelago, which it shares with the Dominican Republic. Ayiti was the indigenous Taíno or Amerindian name for the island...
, and the French
French Caribbean
The term French Caribbean varies in meaning with its usage and frame of reference. This ambiguity makes it very different from the term French West Indies, which refers to the specific, formal French possessions in the Caribbean region...
and Dutch-speaking Caribbean
Kingdom of the Netherlands
The Kingdom of the Netherlands is a sovereign state and constitutional monarchy with territory in Western Europe and in the Caribbean. The four parts of the Kingdom—Aruba, Curaçao, the Netherlands, and Sint Maarten—are referred to as "countries", and participate on a basis of equality...
, though Dutch-speaking Sint Maarten joined the NANP in September 2011) are not part of the system. The only Spanish-speaking country in this plan is the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
(although Spanish-speaking U.S. commonwealth Puerto Rico is as well). Mexican participation was planned, but implementation stopped after two area codes were put into use (Mexico City
Mexico City
Mexico City is the Federal District , capital of Mexico and seat of the federal powers of the Mexican Union. It is a federal entity within Mexico which is not part of any one of the 31 Mexican states but belongs to the federation as a whole...
and northwestern Mexico); these ended in 1991 when Mexico withdrew from the NANP.
The NANP is administered by the North American Numbering Plan Administration (NANPA).
Current NANP number format can be summed up via the following:
- +1-NPA-NXXTelephone exchangeIn the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
-xxxxTelephone numberA telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...
| Component | Name | Number ranges | Notes |
|---|---|---|---|
| +1 | ITU International Telecommunication Union The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies... country calling code |
"1" is also the usual trunk code for accessing long-distance service between NANP numbers. In an intra-NANP context, numbers are usually written without the leading "+ E.123 E.123, also known as Notation for national and international telephone numbers, e-mail addresses and Web addresses is an ITU-T standard for printed representation of telephone numbers, e-mail addresses, and web addresses.-Example formats:... " |
|
| NPA | Numbering Plan Area Code | Allowed ranges: [2-9] for the first digit, and [0-9] for both the second and third digits. | Covers Canada, the United States, parts of the Caribbean Sea, and some Atlantic and Pacific islands. The area code is often enclosed in parentheses. |
| NXX | Central Office (exchange) code | Allowed ranges: [2-9] for the first digit, and [0-9] for both the second and third digits. | Often considered part of a subscriber number. The three-digit Central Office codes are assigned to a specific CO serving its customers, but may be physically dispersed by redirection, or forwarding to mobile operators and other services. |
| xxxx | Subscriber Number | [0-9] for each of the four digits. | This unique four-digit number is the subscriber number or station code. |
For example:
- (234) 235 5678 is valid
- (123) 234 5678 is invalid, because NPA cannot begin with a "1"
The country calling code for the NANP is +1. In international format, an NANP number should be listed thus: +1 301 555 0100 (example using the original area code for Maryland). "1" is also the code often used to make direct-dialed long-distance calls within the NANP.
Each three-digit area code may contain up to 7,919,900 unique phone numbers:
- NXX may begin only with the digits [2-9], providing a base of 8 million numbers: ( 8 x 100 x 10000 ) .
- However, the last two digits of NXX cannot both be 1, to avoid confusion with the N11 codeN11 codeAn N11 code or N11 number is a special abbreviated dialing telephone number within the North American Numbering Plan, which allows access to special services. Each of these eight numbers prevents 10,000 telephone numbers from being used...
s (subtract 80,000). - Despite the widespread usage of NXX "555" for fictional telephone numbers — see 555 (telephone number) — today, the only such numbers specifically reserved for fictional use are "555-0100" through "555-0199", with the remaining "555" numbers released for actual assignment (subtract 100).
- Several other NXX prefixes are generally not assigned: the home area code(s), area codes reserved for future relief nearby, industry testing codes (generally NXX 958 and 959) and special service codes (such as NXX 950 and 976).
Dialing plans
Dialing plans vary from place to place depending on whether an area has overlays (multiple codes serving the same area) and whether the jurisdiction requires toll alerting (a leading 1 for toll calls). The NANPA's web site includes dialing plan information in its information on individual area codes.The standard dialing plan in most cases are as follows:
| Local within area code | Local outside area code | Toll within area code | Toll outside area code | |
|---|---|---|---|---|
| Single code area, with toll alerting | 7D | 7D or 10D | 1+10D | 1+10D |
| Single code area, without toll alerting | 7D | 1+10D | 7D or 1+10D | 1+10D |
| Overlaid area, with toll alerting | 10D | 10D | 1+10D | 1+10D |
| Overlaid area, without toll alerting | 10D or 1+10D | 1+10D | 10D or 1+10D | 1+10D |
Most areas allow permissive dialing of 10D or 1+10D even for calls that could be dialed as 7D. The number of digits dialed is unrelated to whether a call is local or toll when there is no toll alerting. Allowing 7D local dialing across an area code boundary (which is uncommon today and only possible with toll alerting) requires NXX protection on the other side to avoid dialing conflicts.
Most areas permit local calls to be dialed as 1+10D except for Texas, Georgia, and some jurisdictions in Canada which require that callers know which numbers are local and which are toll, dialing 10D for all local calls and 1+10D for all toll calls.
In almost all cases, operator-assisted calls require dialing 0+10D.
Charges
Despite the similar dialing format, calls between different countries and territories that use the NANP are not necessarily charged as domestic. Calls between the US and Canada are treated as international, although typically charged at lower rates than calls to other countries. Calls to other destinations in the NANP area can be high; for example, it generally costs more to call BermudaBermuda
Bermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
from the US than it does to call the UK or Japan, even though the dialing format is the same as the domestic format. Similarly, calls from Bermuda to US numbers, (including toll-free 1-800
Toll-free telephone number
A toll-free, Freecall, Freephone, 800, 0800 or 1-800 number is a special telephone number which is free to the calling party, and instead the telephone carrier charges the called party the cost of the call...
), incur high international rates. This was because many of the island nations at the time implemented a plan of subsidizing the cost of local phone services by directly charging heavier pricing levies on the international Long Distance services.
Because of these higher fees, a handful of scams had taken advantage of customers' unfamiliarity with pricing structure to call the legacy regional area code 809. Some scams lured customers from the U.S. and Canada into placing expensive calls to the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, by representing area code 809
Telephone numbers in the Dominican Republic
Telephone numbers in the Dominican Republic use area code 809 with 829 and 849 as overlay codes. Telecommunications in the Dominican Republic use the North American Numbering Plan country code, 1, followed by the area code in the same form as an internal area code in other NANP countries, such as...
as a regular domestic, low-cost, or toll-free call.
These scams are currently on the decline, with many of the Cable and Wireless service monopolies being opened up to competition, hence bringing rates down. Additionally, many Caribbean territories have implemented local government agencies to regulate telecommunications rates of providers.
History
In order to facilitate direct dialingDirect distance dialing
Direct distance dialing or direct dial is a telecommunications term for a network-provided service feature in which a call originator may, without operator assistance, call any other user outside the local calling area. DDD requires more digits in the number dialed than are required for calling...
calls, the NANP was created and instituted in 1947 by AT&T
AT&T
AT&T Inc. is an American multinational telecommunications corporation headquartered in Whitacre Tower, Dallas, Texas, United States. It is the largest provider of mobile telephony and fixed telephony in the United States, and is also a provider of broadband and subscription television services...
, also known as the Bell System
Bell System
The Bell System was the American Bell Telephone Company and then, subsequently, AT&T led system which provided telephone services to much of the United States and Canada from 1877 to 1984, at various times as a monopoly. In 1984, the company was broken up into separate companies, by a U.S...
, the U.S. telephone semi-monopoly
Monopoly
A monopoly exists when a specific person or enterprise is the only supplier of a particular commodity...
. At first, the codes were used only by long-distance operators; the first customer-dialed calls using area codes did not occur until November 10, 1951, when the first directly dialed call was made from Englewood
Englewood, New Jersey
Englewood is a city located in Bergen County, New Jersey. As of the 2010 United States Census, the city had a total population of 27,147.Englewood was incorporated as a city by an Act of the New Jersey Legislature on March 17, 1899, from portions of Ridgefield Township and the remaining portions of...
, New Jersey to Alameda
Alameda, California
Alameda is a city in Alameda County, California, United States. It is located on Alameda Island and Bay Farm Island, and is adjacent to Oakland in the San Francisco Bay. The Bay Farm Island portion of the city is adjacent to the Oakland International Airport. At the 2010 census, the city had a...
, California. Direct dialing was gradually instituted throughout the country, and by the mid-1960s, it was commonplace in most larger cities.
Originally there were only 86 codes, with the biggest population areas getting the numbers that took the shortest time to dial on rotary telephones. Thus New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
was given 212, Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
213, Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
312, Dallas 214, Detroit 313, Pittsburgh 412; while four areas received the then-maximum number of 21 clicks: South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
(605), North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
(704), South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
(803), and the Maritime Provinces of Canada (902). Additionally, in the original plan a middle digit of 0 indicated that the area code covered an entire state/province, while area codes with a middle digit of 1 were assigned to jurisdictions that were divided into multiple area codes.
At first, area codes were all in the form NYX, where N is any number 2-9, Y is 0 or 1, and X is any number 1-9 (if Y is 0) or any number 2-9 (if Y is 1). The restriction on N saves 0 for calling the operator, and 1 for signaling a long-distance call. The restriction on the second digit, limiting it to 0 or 1, was designed to help telephone equipment recognize the difference between a three-digit "area code" (with 0 or 1 as the second digit) and the three-digit "exchange" prefix (which had avoided 0 or 1 for the second digit, because of restrictions in existing switching equipment). For example, when a caller dialed "202-555-1212", the switching equipment would recognize that "202" was an area code because of the middle 0, and route the call appropriately. If a caller were to dial 345-6789, the 4 would cause the number to be recognized as a long-distance number within the area and routed as such, without waiting for the caller to finish dialing.
In the late 1980s and early 1990s, NANPA (then still part of Bellcore, which is now Telcordia Technologies
Telcordia Technologies
Telcordia Technologies, formerly Bell Communications Research, Inc. or Bellcore, is a telecommunications research and development company based in the United States created as part of the 1982 Modification of Final Judgment that broke up American Telephone & Telegraph...
) began to urge and later require all long-distance calls within each area to be prefixed with the digit 1 to distinguish them from local calls, so that badly needed prefixes with 0 or 1 in the middle could be assigned to local telephone exchange
Telephone exchange
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls...
s. Also, since it had nearly run out of area codes using the above formula, it allowed the assignment of area codes using the form N10, such as 210 in the San Antonio
San Antonio, Texas
San Antonio is the seventh-largest city in the United States of America and the second-largest city within the state of Texas, with a population of 1.33 million. Located in the American Southwest and the south–central part of Texas, the city serves as the seat of Bexar County. In 2011,...
, Texas, area and 410 in eastern Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
. Therefore, someone calling from San Jose to Los Angeles before the change would have dialed 213-555-1234 and after the change 1-213-555-1234, which then allowed 213 to be used as an exchange prefix in the San Jose area.
Until 1991, calls to some areas of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
from the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
were made using NANP area codes, but Mexican participation in the NANP was discontinued in favor of the general international format, using country code +52 instead. Area Code 905 (formerly Mexico City) was re-assigned to the Greater Toronto Area
Greater Toronto Area
The Greater Toronto Area is the largest metropolitan area in Canada, with a 2006 census population of 5.5 million. The Greater Toronto Area is usually defined as the central city of Toronto, along with four regional municipalities surrounding it: Durham, Halton, Peel, and York...
outside of Toronto (which retained Area Code 416), and Area Code 706 (formerly northwest Mexico) was reassigned to northern Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, surrounding the Atlanta region which retained 404.
Expansion of area codes
Canada and the United States have experienced rapid growth in the number of area codes, particularly between 1990 and 2005. There are two main reasons for this. First, there is the increasing demand for telephone services (particularly resulting from widescale adoption of faxFax
Fax , sometimes called telecopying, is the telephonic transmission of scanned printed material , normally to a telephone number connected to a printer or other output device...
, modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
, and mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...
communications).
The second and more important reason is the telecom deregulation of local telephone service in the US beginning in the early-to-mid 1990s. At that time, the Federal Communications Commission began allowing telecommunication companies to compete with the incumbent local exchange carrier
Incumbent local exchange carrier
An ILEC, short for incumbent local exchange carrier, is a local telephone company in the United States that was in existence at the time of the breakup of AT&T into the Regional Bell Operating Companies , also known as the "Baby Bells." The ILEC is the former Bell System or Independent Telephone...
(usually by forcing the existing monopoly service provider to lease infrastructure to other local providers who then resold the service to consumers). However, because of the original design of the numbering plan and telephone switching network that assumed only a single provider, number allocations had to be made in 10,000-number blocks.
Thus, whenever a new local service provider entered a given market, it would be allocated 10,000 numbers by default, even if the provider only obtained a few customers. As more companies began requesting numbering allocations, this caused many area codes to begin exhausting their supply of available numbers (code "in jeopardy" in telecom jargon), and additional area codes were needed. In reality, many of the new telecom ventures were not successful; while the number of area codes started increasing rapidly, this did not necessarily translate to a much larger number of actual telephone subscribers as large blocks of numbers lay unassigned to any "real" subscribers because of the 10,000-number block allocation requirement. When these telecom ventures were merged or bought or liquidated, their blocks went to the successor or went unused. No regulatory mechanism existed to reclaim and reassign these underutilized blocks.
In general, area codes were added either as "splits" (in which an area code was divided into two or more regions, one retaining the older area code and the other area(s) receiving a new code), or "overlay
Overlay plan
In telephony, especially in North America, an overlay plan is the practice of introducing a new area code by applying it onto a geographic area that is already occupied by one or more existing area codes, resulting in two area codes serving the same area.- Methodology :Prior to the introduction of...
s", in which multiple codes are assigned to the same geographical area. Subtle variations of these techniques have been used as well, such as "dedicated overlays", in which the new overlaid code was reserved for a particular type of service, such as cellular phones and pagers (the only true example of this was area code 917 in New York City), and "concentrated overlays", in which a part of the area retained a single code while the rest of the region received an overlay code.
After the remaining valid area codes were used up by expansion, in 1995 the rapid increase in the need for more area codes (both splits and overlays) forced NANPA to allow the digits 2 through 8 to be used as a middle digit in new area code assignments, with 9 being reserved as a "last resort" for potential future expansion. At the same time, local exchanges were allowed to use 1 or 0 as a middle digit. The first area codes without a 1 or 0 as the middle digit were area code 334
Area code 334
Area code 334 is a NANPA area code in the state of Alabama. It was created on January 15, 1995 as a split from area code 205 The 334 area code was one of the first two area codes not to take the N1X or N0X form in the North American Numbering Plan, along with Washington area code 360, which began...
in Alabama and area code 360
Area code 360
Area code 360 is the area code for western Washington state outside of metropolitan Seattle. It began service on January 15, 1995. The area, which encompasses all of western Washington outside of urban King, Pierce, and Snohomish counties and Bainbridge Island, was previously part of area code 206...
in Washington, which both began service on January 15, 1995.
Codes ending in double digits are reserved as easily recognizable codes (ERCs), to be used for special purposes such as toll-free 800, 888, 877, 866 and 855, personal 700
Area code 700
North American area code 700 of the North American Numbering Plan was introduced in 1983 to allow for presubscribing phone numbers to particular interexchange carriers...
numbers, and high-toll 900 numbers, rather than for geographic areas. (Nevada was denied lucky 777 for this reason; it received 775
Area code 775
North American area code 775 is a state of Nevada telephone area code which began a split from area code 702 on December 12, 1998, and finished May 15, 1999. 775 encompasses all of the state of Nevada except for Clark County and the Las Vegas metropolitan area.-External links:* *...
instead when most of Nevada split from 702
Area code 702
North American area code 702 is a NANP telephone code located in Las Vegas, Nevada and also encompasses most of Clark County, Nevada. It was one of the original area codes established in October, 1947, and covered all of Nevada. Due to growth of the Las Vegas area, a new area code was needed...
, which continues to serve the Las Vegas area.)
Splits and overlays
By 1995, many cities in the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
had more than one area code, either through splitting the city into different areas (splits) or having more than one code for the same area (overlays). For example, in Manhattan
Manhattan
Manhattan is the oldest and the most densely populated of the five boroughs of New York City. Located primarily on the island of Manhattan at the mouth of the Hudson River, the boundaries of the borough are identical to those of New York County, an original county of the state of New York...
, subscribers' numbers had the NPA code 212, but two additional codes—first 917 (which initially was exclusively for cellular phones and pagers until that idea was struck down in a Federal court), then 646—were also introduced. This means that the area code must be dialed, even for local calls. In other areas, 10-digit or 11-digit dialing is now required for all local calls. The transition to 10-digit dialing typically starts with a permissive dialing phase in which both 7-digit and 10-digit dialing is optional. During this period, the transition is heavily publicized. After a period of several months, the mandatory dialing phase is introduced, in which 7-digit dialing no longer works. Atlanta was the first US city to have mandatory 10-digit dialing throughout its metropolitan area, roughly coinciding with the 1996 Summer Olympics
1996 Summer Olympics
The 1996 Summer Olympics of Atlanta, officially known as the Games of the XXVI Olympiad and unofficially known as the Centennial Olympics, was an international multi-sport event which was celebrated in 1996 in Atlanta, Georgia, United States....
held there. Atlanta was used as the test case not only because of its size, but also because it enjoyed the world's largest fiber optic network at the time (five times that of New York
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
then), and it was home to BellSouth
BellSouth
BellSouth Corporation is an American telecommunications holding company based in Atlanta, Georgia. BellSouth was one of the seven original Regional Bell Operating Companies after the U.S...
(now part of AT&T), then the Southeastern Regional Bell Operating Company
Regional Bell Operating Company
The Regional Bell Operating Companies are the result of United States v. AT&T, the U.S. Department of Justice antitrust suit against the former American Telephone & Telegraph Company . On January 8, 1982, AT&T Corp. settled the suit and agreed to divest its local exchange service operating...
.
- 7-digit dialing: Nxx xxxx (NPA code not required)
- 10-digit dialing: NPA Nxx xxxx
- 11-digit dialing: 1 NPA Nxx xxxx
The overlap between area codes and exchange prefixes has occasionally produced some confusion because the three digits can be the same for both. Nashua
Nashua, New Hampshire
-Climate:-Demographics:As of the census of 2010, there were 86,494 people, 35,044 households, and 21,876 families residing in the city. The population density was 2,719.9 people per square mile . There were 37,168 housing units at an average density of 1,202.8 per square mile...
, New Hampshire, for example, has a local exchange that begins with (603) 888, which is also an area code for toll-free calls. If somebody in Nashua means to call 1-888-555-1212 but forgets the initial "1," he or she will actually dial the local number 1-603-888-5551. This, however, is generally not a problem in major metropolitan area
Metropolitan area
The term metropolitan area refers to a region consisting of a densely populated urban core and its less-populated surrounding territories, sharing industry, infrastructure, and housing. A metropolitan area usually encompasses multiple jurisdictions and municipalities: neighborhoods, townships,...
s with overlapping area codes, which were mandated by the FCC
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
to dial all ten digits for all local calls so as not to give new numbers or telecommunications providers a "disadvantage."
Expansion issues
Depending on the techniques used for area code expansion, the effect on telephone users varies. In areas in which overlays were used, this generally avoids the need for converting telephone numbers, so existing directories, business records, letterheads, business cards, advertising, and "speed-dialing" settings can retain the same phone numbers, while the overlay is used for new number allocations. The primary impact on telephone users is the necessity of remembering and dialing 10- or 11-digit numbers when only 7-digit dialing was previously permissible.The use of a splitting instead of an overlay generally avoids the requirement for mandatory area-code dialing, but at the expense of having to convert some of the numbers to the new code. In addition to the requirements of updating records and directories to accommodate the new numbers, for efficient conversion this requires a period of "permissive dialing" in which the new and old codes are both allowed to work. Also, many splittings involved significant technical issues, especially when the area splittings occurred over boundaries other than phone network divisions.
As an extreme example of an area code splitting gone somewhat awry, in 1998 area code 612
Area code 612
Area code 612 is the telephone numbering plan code for the city of Minneapolis, Minnesota and a few surrounding areas such as Fort Snelling, St. Anthony and Richfield. It is currently the smallest area code in the state by land area. However, the region used to be much larger, accounting for the...
, which had covered the Minneapolis – Saint Paul Twin Cities, was split to create area code 651
Area code 651
Area code 651 is the telephone numbering plan code for Saint Paul, Minnesota, and the eastern suburbs of the Twin Cities. A dogleg portion also extends to the southeast along the Mississippi River to include cities such as Red Wing...
for St. Paul
Saint Paul, Minnesota
Saint Paul is the capital and second-most populous city of the U.S. state of Minnesota. The city lies mostly on the east bank of the Mississippi River in the area surrounding its point of confluence with the Minnesota River, and adjoins Minneapolis, the state's largest city...
and the eastern metropolitan area. The Minnesota Public Utilities Commission
Minnesota Public Utilities Commission
The Minnesota Public Utilities Commission is the consumer protection agency in the U.S. state of Minnesota charged with the regulation of public utilities such as electric and telephone service. Its commissioners are appointed by the governor....
mandated that the new boundary exactly follow municipal boundaries (which were distinctly different from telephone exchange boundaries), and that all subscribers keep their 7-digit numbers. These two goals were directly at odds with the reason for the split (to generate additional phone numbers), and there were more than 40 exchanges whose territory straddled the new boundary. The result was prefixes duplicated in both area codes, which counteracted much of the benefit of the splitting, with only 200 of 700 prefixes in area 612 moving entirely to area 651. As a result, in less than two years area code 612 again exhausted its supply of phone numbers, and it underwent another three-way split in 2000, creating the new area codes 763
Area code 763
Area code 763 is the telephone numbering plan code for the northwestern suburbs of Minneapolis-St. Paul, Minnesota, including cities such as Plymouth, Maple Grove, and Brooklyn Park...
and 952
Area code 952
Area code 952 is the telephone numbering plan code in Minnesota for the southwestern suburbs of Minneapolis-St. Paul including cities such as Bloomington, Eden Prairie, Edina and Minnetonka...
. Again, the split followed political boundaries rather than rate center boundaries, resulting in additional split prefixes; a few numbers moved from 612 to 651 and then to 763 in less than two years.
Decrease in expansion rate
Recognizing that the proliferation of area codes was largely due to the telecom deregulation act and the assignment of numbers in blocks of 10,000, the FCC instructed NANPA (by then administered by NeuStarNeuStar
Neustar, Inc. is a provider of clearinghouse and directory services to the global communications and Internet industries.-History:Neustar was incorporated in Delaware in 1998. It started as a business unit within Lockheed Martin Corporation...
) to look for a way to alleviate the numbering shortage. As a result a new program called "number pooling" was piloted in 2001, which allowed allocating numbers in blocks of 1,000 rather than 10,000. Because of the design of the switched telephone network, this was a considerable technical challenge and was carried out together with another technically challenging program, local number portability
Local number portability
Local number portability for fixed lines, and full mobile number portability for mobile phone lines, refers to the ability to transfer either an existing fixed-line or mobile telephone number assigned by a local exchange carrier and reassign it to another carrier...
. Since then the program has been rolled out to most parts of the United States and, together with aggressive reclamation of unused number blocks from telecom providers, has reduced the need for additional area codes, so much so that many previously designated area splits and overlays have been postponed indefinitely.
Alphabetic mnemonic system
Another oddity of NANP telephone numbering is the use of alphabetic dialing. On most US and Canadian telephones, three letters appear on each number button from 2 through 9 (as standardized much later by ISO 9995-8ISO/IEC 9995
ISO/IEC 9995 Information technology — Keyboard layouts for text and office systems is an ISO standard defining layouts of computer keyboards. It defines a keyboard as having three groups of key assignments:...
and, in Europe, E.161
E.161
E.161 is an ITU-T recommendation that defines the assignment of the basic 26 Latin letters to the 12-key telephone keypad. Uses for this mapping include:* Multi-tap and predictive text systems* Forming phonewords from telephone numbers...
). This accommodates 24 letters. Historically, the letters Q and Z were omitted, though on some modern telephones they are added, so that the alphabet is apportioned as follows:
2 = ABC
3 = DEF
4 = GHI
5 = JKL
6 = MNO
7 = PRS or PQRS
8 = TUV
9 = WXY or WYZ or WXYZ
No letters are allocated to the 1 or 0 keys (although some corporate voicemail
Voicemail
Voicemail is a computer based system that allows users and subscribers to exchange personal voice messages; to select and deliver voice information; and to process transactions relating to individuals, organizations, products and services, using an ordinary telephone...
systems are set up to count Q and Z as 1, and some old telephones assigned the Z to the digit 0).
Originally, this scheme was meant as a mnemonic device for telephone number prefixes. When telephone numbers in the US were standardized in the mid-20th century, they were made seven digits long, with the first two digits, the prefix, expressed as letters rather than numbers. (Before World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, a few localities used three letters and four numbers; in most cities with customer dialing, phone numbers had only six digits — two letters followed by four numbers.) The prefix was a name, and the first two or three letters (usually shown in capitals) of the name were dialed. Later, the third letter (where previously used) was replaced by a number, or an extra number was added; this generally happened after World War II, although New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
did this in 1930. Thus, the famous Glenn Miller
Glenn Miller
Alton Glenn Miller was an American jazz musician , arranger, composer, and bandleader in the swing era. He was one of the best-selling recording artists from 1939 to 1943, leading one of the best known "Big Bands"...
tune "PEnnsylvania 6-5000
PEnnsylvania 6-5000
PEnnsylvania 6-5000 is claimed by its owner, the Hotel Pennsylvania, to be the oldest continuing phone number in New York City. The telephone number is based on the old telephone exchange name system. The first two letters "PE" in PE6-5000 stand for the rotary dial numbers 7 and 3, making the...
" refers to a telephone number 736-5000, the number of the Hotel Pennsylvania
Hotel Pennsylvania
The Hotel Pennsylvania is a hotel located at 401 7th Avenue in Manhattan, across the street from Pennsylvania Station and Madison Square Garden in New York City.- History :...
, which still bears the same number today. Similarly, the classic film "BUtterfield 8
BUtterfield 8
BUtterfield 8 is a 1960 Metrocolor drama film directed by Daniel Mann, starring Elizabeth Taylor and Laurence Harvey. Taylor, then 28 years old, won an Academy Award for her performance...
" is set in the East Side of Manhattan
Manhattan
Manhattan is the oldest and the most densely populated of the five boroughs of New York City. Located primarily on the island of Manhattan at the mouth of the Hudson River, the boundaries of the borough are identical to those of New York County, an original county of the state of New York...
between roughly 64th and 86th Streets, where the telephone prefixes include 288. This is why, in some works of fiction, phone numbers will begin with "KLondike 5" or "KLamath 5", which translates to 555, an exchange that is unused in most areas.
The letter system was phased out, beginning before 1965 (though it persisted ten years later in some places, and was included in Bell of Pennsylvania
Bell of Pennsylvania
Verizon Pennsylvania, Inc., formerly Bell Telephone Company of Philadelphia, The Bell Telephone Company of Pennsylvania, and Bell Atlantic - Pennsylvania, Inc., who traded as Bell of Pennsylvania, is the Bell Operating Company serving most of Pennsylvania...
directories until 1983), but alphabetic dialing remains as a commercial mnemonic
Mnemonic
A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...
gimmick, particularly for toll-free numbers. For example, one can dial 1-800-FLOWERS
1-800-Flowers
1-800-Flowers is a floral and gift retailer and distribution company in the United States. It was one of the first retailers to use a 24 x 7 toll-free telephone number and the Internet for direct sales to consumers....
to send flowers to someone, or 1-800-DENTIST to find a local dentist. Sometimes, longer phoneword
Phoneword
Phonewords are alphanumeric equivalents of a telephone number. In many countries, there exist letters corresponding to each digit on a telephone keypad...
s are used — for example one might be invited to give money to a public radio station by dialing 1-866-KPBS-GIVE. The "number" is 8 digits long, but only the first seven need be dialed. If an eighth (or more) digit is dialed, the switching system will ignore it. Mobile users may need to manually drop any numbers past the seventh digit as some mobile switching systems will not automatically ignore them, resulting in a failed call. Also, users of smartphone
Smartphone
A smartphone is a high-end mobile phone built on a mobile computing platform, with more advanced computing ability and connectivity than a contemporary feature phone. The first smartphones were devices that mainly combined the functions of a personal digital assistant and a mobile phone or camera...
s including BlackBerry
BlackBerry
BlackBerry is a line of mobile email and smartphone devices developed and designed by Canadian company Research In Motion since 1999.BlackBerry devices are smartphones, designed to function as personal digital assistants, portable media players, internet browsers, gaming devices, and much more...
devices can have difficulty dialing phonewords, as some of those devices do not have the apportioned letters on the keys used for dialing. This can be avoided by accompanying the use of phonewords with the actual numeric phone number, allowing users of such smartphones to dial using the numeric phone number.
In addition to commercial uses, alphabetic dialing has occasionally influenced the choice of regional area codes in the United States. For example, when area 423
Area code 423
Area Code 423 is an area code in Tennessee that covers two separate areas of East Tennessee.Principal cities in the northern part of the area code region are Bristol, Johnson City and Kingsport . The principal cities in the south are Chattanooga and Cleveland.-History:Area code 423 was created in...
(East Tennessee
East Tennessee
East Tennessee is a name given to approximately the eastern third of the U.S. state of Tennessee, one of the three Grand Divisions of Tennessee defined in state law. East Tennessee consists of 33 counties, 30 located within the Eastern Time Zone and three counties in the Central Time Zone, namely...
) was split in 1999, the region surrounding Knoxville
Knoxville, Tennessee
Founded in 1786, Knoxville is the third-largest city in the U.S. state of Tennessee, U.S.A., behind Memphis and Nashville, and is the county seat of Knox County. It is the largest city in East Tennessee, and the second-largest city in the Appalachia region...
was assigned area code 865
Area code 865
Area code 865 serves Knox County, Tennessee, and the eight counties that border it in central East Tennessee. The area incorporates most of the region defined as the Knoxville-Sevierville-La Follette Combined Statistical Area...
, chosen to represent the word "VOL"—short for "Volunteers", the nickname of athletic teams at the University of Tennessee
University of Tennessee
The University of Tennessee is a public land-grant university headquartered at Knoxville, Tennessee, United States...
.
The state of Nevada has previously attempted to obtain area code 777 (lucky 7's), but was unable to secure it.
See Telephone number
Telephone number
A telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...
s
Cellular services and the NANP numbering scheme
A difference between the NANP system and other plans is that, apart from area code 600Area code 600
Area code 600 is a non-geographic Canadian area code, reserved for specialized telecommunications uses such as Teletype, caller-pays cellular, ISDN and mobile satellite communication services...
in Canada, no separate, non-geographical area codes have been created for cellular phones, as is the case in most European and Asian countries, where mobile services are assigned their own prefixes. This means that most North American mobile phones are assigned the same locality-specific codes as landlines, and calls to them are billed at the same rate. Consequently, the "caller pays" pricing model adopted in other countries, in which calls to cellular phones are charged at a higher nationwide rate but receiving calls is free, could not be used. Instead, North American cellular telephone users are also generally charged to receive calls as well ("subscriber pays"). In the past, this discouraged mobile users from using the phones or giving out the number. However, robust price competition among carriers has led to dramatic cuts in the average price per minute for contract customers (for both inbound and outbound calls), which can compare favorably to those in caller-pays countries. Most users select bundle pricing plans that include all the minutes they expect to use in a month. Many carriers also offer free calling between mobile phones on the carrier's network, and some also offer free calling to a list of user-selected phone numbers (which can include both cell phones and landlines).
Some industry observers have blamed "subscriber pays" as one of the main factors in the relatively low mobile phone penetration rate
Mobile phone penetration rate
Mobile phone penetration rate is a term generally used to describe the number of active mobile phone numbers within a specific population.- Penetration rates by region :*List of mobile network operators of the Americas...
in the United States compared to that of Europe. In this model the convenience of the mobility is charged to the subscriber. Callers from outside the local-calling region of the assigned number, however, pay for a long-distance call, although domestic long distance rates are generally lower than the rates in caller-pays systems. Conversely, an advantage of caller-pays is the relative absence of telemarketing
Telemarketing
Telemarketing is a method of direct marketing in which a salesperson solicits prospective customers to buy products or services, either over the phone or through a subsequent face to face or Web conferencing appointment scheduled during the call.Telemarketing can also include recorded sales pitches...
and nuisance call
Nuisance call
Nuisance calls encompass any type of unwanted, unsolicited, telephone call. Common types of nuisance calls include prank calls, telemarketing calls, and silent calls. Obscene phone calls and other threatening calls are criminal acts in most jurisdictions, particularly when hate crime is...
s to mobile numbers. The integrated numbering plan also enables local number portability
Local number portability
Local number portability for fixed lines, and full mobile number portability for mobile phone lines, refers to the ability to transfer either an existing fixed-line or mobile telephone number assigned by a local exchange carrier and reassign it to another carrier...
between fixed and wireless services within a region, allowing users to switch to mobile service while keeping their phone number.
The initial plan for overlays did allow for providing separate area codes for use by mobile phones, faxes, pagers, etc., although these were still assigned to a specific geographical area, rather than the nationwide mobile area codes common to most other countries, and were charged at the same rate as other area codes. Initially, the new area code 917 for New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
was specifically assigned for this purpose within the 5 boroughs; however, a Federal court struck this down and banned the use of an area code for a specific telephony purpose. Since mobile telephony is expanding faster than landline, new area codes typically have a disproportionately large fraction of mobile numbers, although landline and other services rapidly follow and local network portability can blur these distinctions.
The experience of Hurricane Katrina
Hurricane Katrina
Hurricane Katrina of the 2005 Atlantic hurricane season was a powerful Atlantic hurricane. It is the costliest natural disaster, as well as one of the five deadliest hurricanes, in the history of the United States. Among recorded Atlantic hurricanes, it was the sixth strongest overall...
and similar events revealed a possible disadvantage of the methods employed in the geographic assignment of cellular numbers. Many mobile phone users could not be reached, their phones rendered inoperable, even when they were far from the stricken areas, because the routing of calls to their phones depended on equipment in the affected area.
Another related issue for services like mobile telephony is the scarcity of telephone numbers. In contrast to other countries, where mobile and other special-number operators enjoy wide leeway to generate large numbers of telephone numbers, this is not an option in the NANP, with its geographical area codes with a fixed number of digits.
New area codes outside the U.S. and Canada
Prior to 1995, all other NANP countries and territories outside the fifty United States and Canada, including Puerto RicoPuerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
and the U.S. Virgin Islands
United States Virgin Islands
The Virgin Islands of the United States are a group of islands in the Caribbean that are an insular area of the United States. The islands are geographically part of the Virgin Islands archipelago and are located in the Leeward Islands of the Lesser Antilles.The U.S...
, shared the NPA code 809, but they are now able to have separate codes. Code (809)
Telephone numbers in the Dominican Republic
Telephone numbers in the Dominican Republic use area code 809 with 829 and 849 as overlay codes. Telecommunications in the Dominican Republic use the North American Numbering Plan country code, 1, followed by the area code in the same form as an internal area code in other NANP countries, such as...
is now only used by the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
. In 1997 the United States Pacific Territories of the Northern Mariana Islands
Northern Mariana Islands
The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands , is a commonwealth in political union with the United States, occupying a strategic region of the western Pacific Ocean. It consists of 15 islands about three-quarters of the way from Hawaii to the Philippines...
and Guam
Guam
Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...
became part of the NANP, as did American Samoa
American Samoa
American Samoa is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the sovereign state of Samoa...
in October 2004. The Dutch
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
possession of Sint Maarten was originally scheduled to join the NANP on May 31, 2010, but the changeover was postponed to September 30, 2011.
Bermuda:
- Until 1995: +1 809 29x xxxx
- After 1995: +1 441 xxx xxxx
Puerto Rico:
- Until 1996: +1 809 xxx xxxx
- 1996-2001: +1 787 xxx xxxx
- After 2001: +1 787 xxx xxxx or +1 939 xxx xxxx (overlay for entire island)
US Virgin Islands:
- Until 1997: +1 809 xxx xxxx
- After 1997: +1 340 xxx xxxx
Northern Marianas:
- Until 1997: +670 xxx xxxx
- After 1997: +1 670 xxx xxxx
Guam:
- Until 1997: +671 xxx xxxx
- After 1997: +1 671 xxx xxxx
American Samoa:
- Until October 1, 2004: +684 xxx xxxx
- After October 2, 2004: +1 684 xxx xxxx
Sint Maarten:
- Until September 30, 2011: +599 5xx xxxx
- From September 30, 2011: +1 721 xxx xxxx
See also: Split from the 809 Area code
Area codes in the Caribbean
From 1958 to about 1995, most of the British West Indies in the Caribbean Basin plus Bermuda, the U.S. Virgin Islands, the Dominican Republic and Puerto Rico shared a single area code 809 in the North American Numbering Plan...
Fictional telephone numbers
In AmericanUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
shows and film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
s, 555 (or, in older movies and shows, KLondike 5 or KLamath 5) is used as the first three digits of fictional telephone number
Telephone number
A telephone number or phone number is a sequence of digits used to call from one telephone line to another in a public switched telephone network. When telephone numbers were invented, they were short — as few as one, two or three digits — and were given orally to a switchboard operator...
s, so if anyone is tempted to telephone a number seen on screen, it does not cause a nuisance to any actual person.
There are occasions, however, when a non-555 is used in real-life context (often in songs), with varying intents and consequences.
- A classic example is the 19821982 in musicThis is a list of notable events in music from 1982. 1982 was a big year in music with Madonna making her debut as well as the year that Michael Jackson released Thriller which became the world's best selling album and it still holds that title today....
song "867-5309/Jenny867-5309/Jenny"867-5309/Jenny" is a song written by Alex Call and Jim Keller and performed by Tommy Tutone that was released on the album Tommy Tutone 2, on the Columbia Records label. It peaked at number four on the Billboard Hot 100 chart and number one on the Billboard Top Tracks chart in 1982...
" by Tommy TutoneTommy TutoneTommy Tutone is a New Wave band, best known for its 1982 hit "867-5309/Jenny", which peaked at #4 on the Billboard Hot 100. Although it is usually referred to as a San Francisco band, it was actually based in Willits, California, at the time that "Jenny" was released...
, which is still the cause of a large number of nuisance calls, although an Indianapolis plumbing company used both the tune and the number for advertising purposes. - The song "Diary" by Alicia KeysAlicia KeysAlicia Augello Cook , better known by her stage name Alicia Keys, is an American singer-songwriter, record producer, and occasional actress. She was raised by a single mother in the Hell's Kitchen area of Manhattan in New York City. At age seven, Keys began playing the piano...
says to call "489-4608 and I'll be here." It was intended to be called only by people in New York to get her voicemail. - At the time that it was recorded in the late 1970s, The B-52'sThe B-52'sThe B-52's are an American rock band, formed in Athens, Georgia in 1976. The original line-up consisted of Fred Schneider , Kate Pierson , Cindy Wilson , Ricky Wilson , and Keith Strickland . Following Ricky Wilson's death in 1985 Strickland switched to guitar...
song "6060-842" could not result in a nuisance call, because telephone prefixes could not employ zero as the second digit. Since then, however, the rules governing prefix morphology have changed, causing 606-0842 to become a valid telephone number. - In 2003, the movie Bruce AlmightyBruce AlmightyBruce Almighty is a 2003 American comedy film directed by Tom Shadyac and written by Steve Koren, Mark O'Keefe and Steve Oedekerk. It stars Jim Carrey as Bruce Nolan, a down-on-his-luck TV reporter who complains to God that He isn't doing His job correctly, and is then offered the chance to try...
caused controversy because God contacts Bruce, via pager, using an actual phone number 776-2323. The DVD and television versions changed the display of the pager to 555-0123. - In 1991, a version of Madonna: Truth or DareMadonna: Truth or DareMadonna: Truth or Dare is a 1991 American documentary film chronicling the life of American singer-songwriter Madonna during her 1990 Blond Ambition World Tour...
showed Madonna giving out her actual phone number. The phone number was quickly changed and the scene was cut from the movie shortly afterwards. - In movies that took place in New York City in the 1940s to the 1960s, numbers like "PLaza 3-9970", "BOwling green 3-9970" or "PLaza 3-5598" were used. At that time, the Public Switched Telephone Network in New York City utilized mainly mechanical switches such as PanelPanel switchThe panel switching system was an early type of automatic telephone exchange, first put into urban service by the Bell System in the 1920s and removed during the 1970s...
and #1 crossbarNumber One Crossbar Switching SystemThe Number One Crossbar Switching System, or 1XB switch, was the primary urban local telephone exchange design used by the Bell System in the mid-20th century. Its switch fabric topology was based on the earlier urban panel switch system, which, in turn, was based on the turn of the century...
and those were "test numbers" that always rang to a busy signal.
Similarly, not all numbers beginning with "555" are fictional. For example, 555-1212 is the number for directory assistance
Directory assistance
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.-Technology:...
in many places. In many, but not all areas, dialing "555" numbers other than 555-1212 will actually get you to directory assistance as well. In fact, only 555-0100 through 555-0199 are now reserved for fictional use, with the other numbers having been released for assignment. Since "1xx" exchanges are generally not assigned, some movies have started to use fictional telephone numbers starting with "1".
Future expansion of NANP
The North American Numbering Plan Administration (NANPA) is now overseen by NeuStarNeuStar
Neustar, Inc. is a provider of clearinghouse and directory services to the global communications and Internet industries.-History:Neustar was incorporated in Delaware in 1998. It started as a business unit within Lockheed Martin Corporation...
, which will probably face the task of adding one or two digits to each number, likely sometime after 2038. During that time, all public and private phone systems within the NANP area will have to be upgraded and reprogrammed (or even replaced) to recognize the new dialing rules.
One plan being considered adds a 1 or 0 either to the beginning or end of the area code, or the beginning of the local 7-digit number (or both), which will require mandatory 11-digit dialing (even for local calls), between any two NANP numbers, well before the transition period. In another proposal, existing codes would be changed to "x9xx" (e.g. San Francisco's 415 would become 4915); once that conversion is complete, the new second digit would be opened for a new range. (Compare PhONE Day in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, which added a "1" to the beginning of area codes in preparation for later using other digits, such as "2", for new area codes.) Other proposals include reallocating blocks of numbers assigned to smaller long distance carriers or unused reserved services.
NANPA previously coordinated an expansion of long-distance carrier
Interexchange carrier
An Interexchange Carrier is a U.S. legal and regulatory term for a telecommunications company, commonly called a long-distance telephone company, such as MCI , Sprint and the former AT&T in the United States...
access ("dial-around") codes from five digits (such as 10-321) to seven (10-10-321), in 1998. Vertical service code
Vertical service code
A vertical service code or VSC is a special code dialed prior to a telephone number that engages some type of special telephone service...
s, such as *69 (callback
Callback (telecommunications)
In telecommunications, a callback occurs when the originator of a call is immediately called back in a second call as a response.- International calling :...
) and *70 (suspend call waiting
Call waiting
Call waiting , in telephony, is a feature on some telephone networks. If a calling party places a call to a called party which is otherwise engaged, and the called party has the call waiting feature enabled, the called party is able to suspend the current telephone call and switch to the new...
), have been designed to allow the use of both two- and three-digit codes.
Special numbers and codes
Some common special numbers in the North American system:- 0 - Operator assistanceOperator assistanceAn operator-assisted call is one in which the calling party places a telephone call which requires an operator to provide some form of assistance in completing the call...
- 00 - Long-distance operatorLong-distance operatorIn telephony, the long-distance operator is a telephone operator available to assist with making long distance telephone calls, answering billing questions, making collect calls and other functions, including emergency assistance....
assistance - 011 - International Access Code. (For all destinations outside the NANP)
- 01 - International Access Code using operator assistance. (For all destinations outside the NANP)
- 10x xxxx - Used to select use of an alternative long-distance carrierInterexchange carrierAn Interexchange Carrier is a U.S. legal and regulatory term for a telecommunications company, commonly called a long-distance telephone company, such as MCI , Sprint and the former AT&T in the United States...
- 2112-1-12-1-1 is a special abbreviated telephone number reserved in Canada and the United States as an easy-to-remember three-digit telephone number meant to provide quick information and referrals to health and human service organizations.-United States:...
- Community information or social services (In some cities), formerly payphone refund line (and prior to that, used to access "long distance" operators or telephone ring test in some cities) - 3113-1-1The non-emergency telephone number 3-1-1 is a special N-1-1 telephone number in many communities in Canada and the United States that provides quick, easy-to-remember access to non-emergency municipal services or a Citizen Service Center...
- City government or non-emergency police matters such as noise complaints, suspicious people, minor injuries and non-working streetlights and parking meters, etc. (In some cities) - 4114-1-14-1-1 is the telephone number for local directory assistance in the United States and Canada. One exception is the Pacific Northwest, which used 1-1-3 until the mid-1980s. Until the early 1980s, 4-1-1 calls were free in most states....
- Local telephone directory service (Some telephone companies provide national directory assistance) - 5115-1-15-1-1, initially designated for road weather information, is a transportation and traffic information telephone hotline in some regions of the United States and Canada. Travelers can dial the three-digit telephone number 5-1-1 on traditional landline telephones and most mobile phones. It is an N11...
- Traffic, road, and tourist information or reads backAutomatic number announcement circuitAn automatic number announcement circuit is a special telephone number that is meant to be used by phone company technicians and other telecommunications technicians to determine the phone number of a particular line....
the number you are calling from (i.e. drop line ID) (In some cities and states) - 6116-1-1For customers of some telephone companies in Canada and in the U.S., 611 is the abbreviated dialing telephone number used to report a problem with telephone service, or with a payphone...
- Telephone line repair service (Some telephone companies use this instead of 4104 or 811). Also used by mobile telephone companies to reach customer service - 7117-1-1In Canada and the U.S., the 711 telephone number is used for the Telecommunications Relay Service to translate from TDD for the deaf to speech, and vice versa. The relay service allows deaf people to converse with the hearing over the phone through an operator. 711 is one of eight N11 codes for...
- Relay service for customers with hearing or speech disabilities - 8118-1-1In the North American Numbering Plan , particularly in Canada and the U.S., the telephone number 811 has traditionally been a direct line to the business office of the telephone company providing service on the line...
- "Dig safe" underground pipe safety line in the United States, non-urgent telehealthTelehealthTelehealth is the delivery of health-related services and information via telecommunications technologies. Telehealth could be as simple as two health professionals discussing a case over the telephone or as sophisticated as doing robotic surgery between facilities at different ends of the...
services in Canada, formerly telephone company business office, mainly to encourage people not to hit telephone or power lines when they dig. - 9119-1-19-1-1 is the emergency telephone number for the North American Numbering Plan .It is one of eight N11 codes.The use of this number is for emergency circumstances only, and to use it for any other purpose can be a crime.-History:In the earliest days of telephone technology, prior to the...
- Emergency dispatcherEmergency telephone numberMany countries' public telephone networks have a single emergency telephone number, sometimes known as the universal emergency telephone number or occasionally the emergency services number, that allows a caller to contact local emergency services for assistance. The emergency telephone number may...
for fire department, ambulance, police etc. - 830 or 958 or 9580 or 998 - Returns the number on the line via a recorded voice (in some areas)
- (Area Code) + 555-1212 - Non-local directory service
There are also special codes
Vertical service code
A vertical service code or VSC is a special code dialed prior to a telephone number that engages some type of special telephone service...
, such as:
- *51 and 1151 A history of unanswered calls on a telephone number, useful for those who are not Caller IDCaller IDCaller ID , also called calling line identification or calling number identification or Calling Line Identification Presentation , is a telephone service, available in analog and digital phone systems and most Voice over Internet Protocol applications, that transmits a caller's number to...
subscribers. - *57 and 1157 Used to "traceCall tracingIn telecommunication, call tracing is a procedure that permits an entitled user to be informed about the routing of data for an established connection, identifying the entire route from the origin to the destination....
" harassing, threatening, abusive, obscene, etc. phone calls, and keep results of trace at phone company. - *66 and 1166 To keep retrying a busy-line (see also Called-party camp-onCalled-party camp-onIn telecommunication, a called-party camp-on is a communication system service feature that enables the system to complete an access attempt in spite of issuance of a user blocking signal. This is most often found in a switchboard system at a company...
) - *67 and 1167 Caller ID Block
- *69 and 1169 Call Return caller may press '1' to return call after hearing number
- *70 and 1170 Cancel call waiting on a call-by-call basis
- *71 and 1171 Three way calling, which lets a person talk to people in two different locations at the same time.
- *74 and 1174 Speed dialing, which allows someone to quickly dial any of eight frequently called numbers using a one-digit code, from any phone on their line. *75 allows a total of 30 speed-call numbers.
- *82 and 1182 Releases Caller ID block on a call-by-call basis
Note: The four digit numbers do not work in some areas. The codes prefixed with the "*" symbol are intended for use on Touch-Tone telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...
s, whereas the four-digit numbers prefixed 11xx are intended for use on older rotary dial telephones, where the Touch-Tone * symbol is not available.
Not all NANPA countries use the same codes. For example, the emergency telephone number
Emergency telephone number
Many countries' public telephone networks have a single emergency telephone number, sometimes known as the universal emergency telephone number or occasionally the emergency services number, that allows a caller to contact local emergency services for assistance. The emergency telephone number may...
is not always 911: Trinidad and Tobago
Trinidad and Tobago
Trinidad and Tobago officially the Republic of Trinidad and Tobago is an archipelagic state in the southern Caribbean, lying just off the coast of northeastern Venezuela and south of Grenada in the Lesser Antilles...
and Dominica
Dominica
Dominica , officially the Commonwealth of Dominica, is an island nation in the Lesser Antilles region of the Caribbean Sea, south-southeast of Guadeloupe and northwest of Martinique. Its size is and the highest point in the country is Morne Diablotins, which has an elevation of . The Commonwealth...
uses 999
999 (emergency telephone number)
999 is an official emergency telephone number in a number of countries which allows the caller to contact emergency services for urgent assistance....
, as in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. The country of Barbados
Barbados
Barbados is an island country in the Lesser Antilles. It is in length and as much as in width, amounting to . It is situated in the western area of the North Atlantic and 100 kilometres east of the Windward Islands and the Caribbean Sea; therein, it is about east of the islands of Saint...
uses 211 for police force
Police
The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...
, 311 for fire
Fire station
A fire station is a structure or other area set aside for storage of firefighting apparatus , personal protective equipment, fire hose, fire extinguishers, and other fire extinguishing equipment...
, and 511 for ambulance
Ambulance
An ambulance is a vehicle for transportation of sick or injured people to, from or between places of treatment for an illness or injury, and in some instances will also provide out of hospital medical care to the patient...
, while Jamaica
Jamaica
Jamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...
uses 114 for directory assistance, 119 for police force
Police
The police is a personification of the state designated to put in practice the enforced law, protect property and reduce civil disorder in civilian matters. Their powers include the legitimized use of force...
, and 110 for fire
Fire station
A fire station is a structure or other area set aside for storage of firefighting apparatus , personal protective equipment, fire hose, fire extinguishers, and other fire extinguishing equipment...
and ambulance
Ambulance
An ambulance is a vehicle for transportation of sick or injured people to, from or between places of treatment for an illness or injury, and in some instances will also provide out of hospital medical care to the patient...
services.
Despite its early importance as a share of the worldwide telephone system, few of the NANP's codes, such as 911, have been adopted outside the system. Determining that 911 requires unnecessary rotation time on rotary dial telephones, the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
has adopted its own standardized number of 112
1-1-2
112 is the principal emergency telephone number that can be dialed free of charge from any telephone or any mobile phone in order to reach emergency services in the European Union , its candidates for accession, members of the EEA agreement, as well as several other countries in the world...
, while countries in Asia and the rest of the world use a variety of other two- or three-digit emergency telephone number
Emergency telephone number
Many countries' public telephone networks have a single emergency telephone number, sometimes known as the universal emergency telephone number or occasionally the emergency services number, that allows a caller to contact local emergency services for assistance. The emergency telephone number may...
combinations. The 112 code is gaining prevalence because of its preprogrammed presence in mobile telephones that conform to the European GSM standard. The European Union and many other countries have chosen the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...
's 00 as their international access number instead of 011. The toll-free prefix 800 has been widely adopted elsewhere, including as the international toll-free country code. It is often preceded by a 0 rather than a 1 in many countries where 0 is the trunk prefix
Trunk prefix
A trunk prefix is the number to be dialed in a domestic telephone call, preceding any necessary area codes and subscriber numbers. When the number is called from overseas, the trunk prefix is omitted by the caller. In most countries, such as Australia, Germany and the United Kingdom, the trunk...
.
See also
- Bell SystemBell SystemThe Bell System was the American Bell Telephone Company and then, subsequently, AT&T led system which provided telephone services to much of the United States and Canada from 1877 to 1984, at various times as a monopoly. In 1984, the company was broken up into separate companies, by a U.S...
- List of North American Numbering Plan area codes
- List of country calling codes
- List of original area codes
- List of area code overlays
- Vertical service codeVertical service codeA vertical service code or VSC is a special code dialed prior to a telephone number that engages some type of special telephone service...
External links
- North American Numbering Plan Administration (NANPA)
- Canadian Numbering Administrator
- Caribbean numbering plan for several islands in the NANP
- Map of the original 86 area codes from 1947
- Animation of US area codes since 1947
- North American Numbering Council
- NANP Discussion 2003 Document - "Understanding the North American Numbering Plan"