The North American Numbering Plan (NANP) is a system for three-digit area codes and seven-digit telephone numbers that direct telephone calls to particular regions on a public switched telephone network (PSTN), where they are further routed by the local network. It is applied to the United States and its territories; Canada; Bermuda; and many Caribbean nations.
Developed in 1947 and first implemented in 1951 by AT&T, the NANP set out to simplify and facilitate direct dialing of long distance calls. It initially applied only to the U. S. and Canada, but at the request of the British Colonial Office, Bermuda and the British West Indies (including Trinidad and Tobago, just off the coast of Venezuela) were added to the North American system given their historic telecommunications administration through Canada as parts of the British Empire and their continued close associations with that country. Compare-Wireless-Plans is not associated by ownership or membership with any cellular, PCS or wireless service provider companies.
Despite the "North American" name of the calling plan, Mexico and the Central American countries are not part of the system, although Mexican participation was planned and partly implemented, with direct dialing from the NANP to some parts of Mexico until 1991.
The NANP is administered by the North American Numbering Plan Administration (NANPA).
Current NANP can be summed up via the following:
NPA = [2-9][0-8][0-9]Nxx = [2-9][0-9][0-9]Station = [0-9][0-9][0-9][0-9]Dialing plans vary from place to place depending on whether an area has overlays (multiple area 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.
In areas without overlays and without toll alerting, calls within an area code are dialed as seven digits (7D) and calls outside the area code as 1 followed by 10 digits (1+10D). Most areas allow permissive dialing of 1+10D even for calls that could be dialed as 7D. By Features. The number of digits dialed is unrelated to whether a call is local or toll.
In areas with overlays, local calls are all dialed as 10D. (In New York City, the preferred form is 1+10D but 10D also works. ) In areas without toll alerting, all calls to numbers within the caller's area code and overlay codes serving the same area can be dialed as either 10D or 1+10D, while calls to other area codes must be 1+10D. In areas with toll alerting, all toll calls must be dialed as 1+10D. Most areas permit local calls to be dialed as 1+10D except for Texas which requires that callers know which numbers are local and which are toll, dialing 10D for all local calls and 1+10D for all toll calls. Cell Phone Deals T-Mobile Wireless Plans.
The current profusion of dialing plans is quite confusing, and it appears likely that all areas will converge on 1+10D even in places where other forms are permitted. Residents of areas with toll alerting tend to feel quite vehemently that it is a necessary service, while residents of areas without toll alerting do not necessarily miss it, even though it means they might be charged for a telephone call with no warning.
Despite the similar dialing format, calls between different countries and territories that use the NANP are not 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 Bermuda from the US than it does to call the UK or Japan, even though the dialing format is the same. Similarly, calls from Bermuda to US numbers, (including toll-free 1-800), incur high international rates. By Category. This was because many of the island nations at the time implemented a plan of subsidizing the cost of local phone services, from directly charging heavier pricing levies on the international Long Distance services. On account of these higher fees, a handful of scams had taken advantage of customers' unfamiliarity with pricing structure to call the legacy regional 809 area code. Some scams lured customers from the U. S. and Canada into placing expensive calls to the Caribbean, by representing the 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 thus bringing rates down. separate report on prepaid wireless covers pay-as-you go wireless plans.
In order to facilitate direct dialing calls, the NANP was created and instituted by AT&T, then the U. S. telephone monopoly, in 1947. However, the first customer-dialed calls using area codes did not occur until late 1951. Originally there were 86 codes, with the biggest population areas getting the numbers that took the shortest time to dial on rotary phones. That is why New York City was given 212, Los Angeles given 213, and Chicago 312, while Vermont received 802 (a total of 20 clicks, 8+10+2). 2003 - Compare Wireless Plans. Four areas received the then-maximum number of 21 clicks: South Dakota (605), North Carolina (704), South Carolina (803), and Nova Scotia/Prince Edward Island in the Canadian Maritimes (902). Additionally, in the original plan a middle digit of zero generally indicated the number was for an entire state or province, while a middle digit of one indicated that it was for a smaller region.
At first, area codes were in the form N-Y-X, where N is any number 2~9, Y is 0 or 1, and X is any number 1~9. 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 and a three-digit prefix to the telephone number. For example, when a caller dialed "1-202-555-1212", the switching equipment would recognize that "202" was an area code because of the middle 0, and route the call appropriately. Consumers Union recommends the following 15 key questions to ask when shopping for wireless service:. If a caller were to dial 1-345-6789, the 4 would be recognized as a long-distance call within the area code and routed as such, without waiting to see or guessing at how many digits the caller meant to enter.
In the late 1980s and early 1990s, NANPA (then still part of Bellcore) began to urge and later require all long-distance calls within each area to include the code, so that badly-needed prefixes with 0 or 1 in the middle could be assigned to local telephone exchanges.
Until 1991, calls to some areas of Mexico from the United States and Canada were made using the North American Numbering Plan area codes. For example, to call a number in northwest Mexico and Mexico City before 1991:
1 905 xxx xxxx (Mexico City)1 706 xxx xxxx (northwest Mexico)From that year, this was discontinued in favor of the international format:
011 52 5 xxx xxxx (Mexico City; now 011 52 55 xxxx xxxx)011 52 6 xxx xxxx (northwest Mexico; now 011 52 6xx xxx xxxx)Due to a combination of increasing demand for telephone services (particularly due to widescale adoption of fax and cell phone communications), and the practice of allocating phone numbers in large blocks to companies for issuing, many area codes began to exhaust their supply of available numbers (code "in jeopardy" in telecom jargon), and additional area codes were needed. 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 areas receiving a new code), or "overlays", in which multiple area codes were 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 area code was reserved for a particular type of service, such as cell phone and fax machine; while this is still generally done, it is now against Federal law to absolutely assign an area code for this) and "concentrated overlays" (in which some of the area retained a single area code, while the rest of the region received an overlay code). Compare phones, plans & accessories.
After the remaining valid area codes were used up in expansion, in 1995 the rapid increase in the need for more area codes (both splits and overlays) forced NANPA to allow the digits 2~8 to be used as a middle digit in new area code assignments, with 9 being reserved as a "last resort" for potential future expansion. Area codes, or "number planning areas" ending in double digits, such as toll-free 800, 888, 877, and 866, personal 700 numbers, and high-toll 900 numbers, are reserved as Easily-recognizable codes (ERCs) and are not issued to actual areas. (Nevada was declined lucky 777 for this reason, however the Florida Space Coast area did get the 321 "countdown" area code as requested by Richard Cheshire [1]. )
By 1995, many cities in the United States and Canada had more than one area code, either through splitting the city into different areas (splits) or having more than one area code for the same geographical area (overlays). For example, in Manhattan, New York, subscribers' numbers had the NPA code 212, but two additional codes—first 917 (which initially was exclusively for cell phones and faxes until struck down in a federal court), then 646—were also introduced. This means that the area code must be dialed, even for local calls. Purchase cell phones, service plans & cell phone accessories at LetsTalk. In other areas, 10-digit or 11-digit dialing is now required for all local calls. Atlanta, Georgia, was the first city in the United States to have mandatory 10-digit dialing throughout its metro area, roughly coinciding with the Olympic Games in Atlanta. At first, the new calling plan wasn't mandatory but was highly encouraged by television advertisements. After some time, though, it became mandatory to dial all 10 digits.
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