The “NANP” is a short form for “North American Numbering Plan.” It is a telephonic numbering plan that includes 24 countries and territories, including the United States, Canada, Bermuda, and 17 other nations of the Caribbean. In the NANP or North American Numbering Plan, there is “3-digit” area code and a “7-digit” telephone number.
It is working structure is like the NANP or North American Numbering Plan separates the territories of its member countries into Numbering Plan Areas, which are also called NPAs. Each NPA or numbering plan area is recognized by its three-digit number or code, which very often known as “area code.”
The procedure and rules of the numbering plan area or NPAs do not allow the area code to lead with the digits “0” or “1”. This rule similarly works for the central office's codes. The digit “0” has been used conventionally for operator-assisted telephone calls where the digit “1” was slightly ignored in switching equipment as a leading digit. These digits “0” or “1” could not be acclaim authorized from the intermittent loop disconnections and barriers when users operate their telephones.
Future format expansions of NPAs are reserved with “9” as its second digit. Area codes, which have there, last two digits same for example if an area code is “322” or “755” these are commonly known as “easily recognizable codes” or “ERC” and these codes are reserved.
Current projects that are on progress are the toll-free codes such as 800, 888, 877, 866, 855, 844, and 833. Area code “822” is expected to come in use in the future, followed by 880 then 887 then 889.
Quite contrarily to the beliefs of most of the Americans, area codes have outside existence from the US. There are four hundred and five (405) area codes in all over the world from which three hundred and twenty-six (326) in the United States, forty-two (42) in Canada, seventeen (17) are non-geographic, and twenty (20) are others, which are mostly in the Caribbean.
California is the state, which has most of the area codes at 34 followed by Texas (27), New York (19), Florida (17), and Illinois (13).
In the United States and its territories, Canada and the Caribbean, the structuring and allotment of telephone numbers are maintained and regulated by the “NANPA” or North American Numbering Plan Administration. NANPA structures the distribution and allocation of the area codes and all the prefixes that are used in starting of the telephone numbers which are used by the various phone companies. The general format of a phone number in all or any of these countries is NPA-NXX-XXXX or (NPA) NXX-XXXX.
Generally, NPAs or area codes come into existence during the early 1940s. NPA area codes were created and developed by AT&T and the bell system to distribute the coverage range into different NPAs or number plan areas. These NPAs are commonly known as area codes. Direct calling in the long distances did not start until the early 1950s. Some area codes plan is reserved for special projects. Not all the NPAs or area codes are currently in use. For example, an area code “800” is reserved for toll-free calls where the “receiver” of the phone will be charged instead of the “dialer” of the phone.
“NXX” is, in turn, the next three digits of a landline or a telephone number. This is also called as the “prefix” or “exchange.”
The last four digits of the phone number are commonly known as “subscriber” or “local number.” Based on the total number of active NPAs and NXX combinations reserved which in each case one would have up to 10,000 subscriber numbers, the present total possible number of telephone numbers is “1,699,140,000”.
According to the US Census and the World Bank, based on the total population of the US and Canada it leaves four numbers for every person present. There is no longer in existence for home phones or landlines. Many of the telephone or phone numbers are now used for fax machines, cell phones, wireless phone, or internet connections;, therefore, one person may need multiple phone lines.