North American Numbering Plan

As a North American Numbering Plan (NANP; German: " North American Numbering Plan" ) refers to a system of three-digit area codes or ten-digit telephone numbers, which is used mainly in the USA, Canada and many Caribbean states. All NANP countries have the same common international code 1.

Design and Structure

North American area codes ( Numbering Plan Area (NPA ), areacode ) are always the same length and consist of three digits, the first of which is in the range 2-9 (N). Large cities were originally lower digits and thus at shorter pulse dialing codes. Meanwhile, larger places several primaries, some of them more for the same area ( overlays ). Therefore, based on the first digit no rough estimate of the geographical position is possible. Also a distinction between landlines and mobile numbers is not possible in the North American Numbering Plan, because mobile numbers are sorted under the usual primaries.

The subscriber number also has a fixed length of seven digits and is composed of a prefix consisting of three digits, indicating the switch, and four more digits.

Initially, the primaries and the subscriber numbers from the second digits were clearly distinguishable: primaries got here a 0 or 1 Meanwhile, however, are both local subscriber numbers with 0 or 1 ( since the late 1980s ) as well as numbers with the digits 2-8 (since 1995 ) awarded as the second digit. To distinguish therefore other methods must be used ( see below).

The prefix 555 indicates fictional 555 telephone numbers.

Dial plan

Originally it was clearly between calls within an area code and outside distinguished by the second digit. For example was when dialing " 202-555-1234 " clear that a 202 area code was because no subscriber number had a 0 in the second place; " 555-1234 ", however, is a local number, since no code had a 5 second. Still had to be selected for a one ( paid ) long distance calls.

Since this is no longer possible since the late 1980s, different dial plans have from region to region developed:

In some areas, one makes use of the fact that long distance calls must be dialed using 1. One therefore does not assign local phone numbers that start with a local rate (usually free ) to reach your area code.

In other areas, the 1 serves as a sign that a number with area code to be dialed; Only numbers within the same area code can be dialed directly and without the area code.

In other areas, especially in large cities, but always the full ten-digit number must be ( including area code ), even for local calls. The one serves as a sign of a ( paid ) long distance call.

History

The NANP was developed in 1947 by AT & T and 1951 put into operation in order to enable the direct dial long-distance calls. Introduced this common in the U.S. and Canada 87 primaries after the NYX scheme ( 0-9 N: 2-9, Y: X 0 and 1 ).

Originally intended only for the U.S. and Canada, it was in 1955 at the request of the British Colonial Office in Bermuda and the British West Indies (including Trinidad and Tobago and The Bahamas), expanded as their historical Telecommunications Administration went through Canada, because all part of the British Empire, were passed in the compounds in each country by telegraph and the All -Red Line System. At times, Mexico City and parts of northwestern Mexico also taken in the NANP, but were later converted to the single country code for Mexico. A certain connection of the Mexican area codes with the NANP shines through on. They are after the partially complementary scheme NYX (N: 1-9 2-9, Y: 1-9, X) constructed, that is the second or third place is never 0 The first digit refers to the region. There are also a few two-digit codes.

All countries share a code system, which has three-digit area codes. In the 1960s, 70s and 80s, the system was relatively stable from the mobile age, many new area codes are added. Mobile is operated via the normal primaries, so that mobile numbers from landline numbers are externally indistinguishable.

When the first digit 0 for the (manual ) switching and the one set aside for long-distance calls were. The restriction of the second digit was used to distinguish between codes and subscriber numbers.

However, the early 1990s also had the 0 and 1 assigned local exchanges due to number shortage in the middle of the NANPA (then part of Bellcore ); 1995, the primaries were almost through subdivisions and overlays, so that the number was 2-8 awarded in the middle of the primaries; 9 is used for future expansion.

The January 1, launched in 1958, is uniform for the entire Caribbean area code 1 809 has been split from 1 October 1995 until 1 June 1998 to the numbers currently in force.

The North American Numbering Plan Administration ( NANPA ) now belongs to private company NeuStar Inc.. Due to continuous number scarcity additional points must be used within the numbers in the near future.

Number overview of the NANP

The list includes independent countries, British Overseas Territories (UK ), outside areas of the United States (U.S.) and a Dutch part of the island (NA). States in the United States and Canada are listed separately.

The fat- listed 87 prefixes (USA: 78, Canada: 9) are already used since January 1, 1947. Another 56 numbers ( USA: 48, Canada: 7 Caribbean: 1) with a 0 or 1 were in second place in the years 1950 to 1994, all other (previously 267, of which the Caribbean: 25, USA: 196 Canada: 46 ) numbers introduced due to number shortage from 1995 and already reserved.

The tens blocks of numbers 370-379 and 960-969 are reserved by the INC (Industry Numbering Committee).

The number of blocks 29X - 99X (X = 0-8) are reserved for future extensions.

Additional 208 numbers are still available.

Overview of country of NANP

The local networks 670 and 671 changed on 1 July 1997, 684 on 2 October 2004 by the number space 6 ( Oceania / Pacific ) for space number 1, where they could keep their own area code each and just now additionally select nor 1 is.

Canadian Provinces and Territories in NANP

More already reserved for Canada numbers: 257, 263, 273, 354, 367, 368, 382, 387, 428, 460, 468, 474, 487, 537, 548, 568, 584, 672, 683, 742, 753, 825, 851, 871, 879, 942

U.S. states in the NANP

More already reserved for the U.S. numbers: 220, 272, 353, 582, 835, 943

Non Geographical area codes in the NANP

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