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NANP stands for North American Numbering Plan. It is a telephone numbering plan designed and used commonly by 19 different countries and territories in North America. These countries include the United States and its territories, Anguilla, Antigua & Barbuda, Bermuda, the Bahamas, Barbados, the British Virgin Islands, Canada, the Cayman Islands, Dominica, the Dominican Republic, Grenada, Jamaica, Montserrat, St. Kitts and Nevis, St. Vincent and the Grenadines, St. Lucia, Turks & Caicos and Trinidad and Tobago. The NANP aims to reduce the complexity of dialing long distance international calls, making direct dialing easy for long distance calls within the NANP network. The NANP utilizes a three digit area code and a seven digit local telephone number system. Through this system, calls can be directly switched to the particular area of the NANP Public Switched Telephone Network (PSTN), from where they can be further transferred to the destination using the local networks.[1][2]


The American Telephone & Telegraph Corporation (AT&T), originally known as Bell System, developed the North American Numbering Plan in the early 1950s to assist the direct dialing of calls. On November 10, 1951, the first long distance directly dialed call was made from Englewood, New Jersey to Alameda, California. Before this day, dialing codes were used only by long distance operators, as the system did not facilitate direct calling. By the mid-1960's, almost all major North American countries and territories had successfully implemented the program. Initially, 86 codes were used to represent the different areas; these codes were allotted to different regions of North America according to the density of the population. The regions with high density population were allotted the lower numbers while the regions with low population were allotted the higher numbers. Thus, New York was allotted 212, Los Angeles 213, Chicago 312, Dallas 214, Detroit 313, and Pittsburgh 412, while South Dakota was given 605, North Carolina 704, South Carolina 803, and the Maritime Provinces of Canada 902.[3][4][5]

Code Plan

Earlier the codes were designed in the form of N-Y-X, in which N is a number between 2-9, Y is either 0 or 1 and X represents any number from 1-9 (if Y is 0) or any number between 2-9 (if Y is 1). This restriction provides assistance to allocate some essential service with special codes, such as 0- Operator, 1- for signaling long distance calls, 00- long distance operator, 011- international access code, 911- for emergency services such as fire, ambulance and police and so on. But in the mid the 1990’s and early 21st century there was rapid growth in telecommunication industry. This demand raised the necessity for the allocation of more codes. However, the restrictions on the code format limited the number of codes to be allocated. This forced the North American Numbering Plan Administrator (NANPA), which acts as an administrating organization of the NANP, to expand the number range. The restriction on middle term ‘Y’ was lifted and the new area codes can use any number from 2 and 8 for the middle term of the three digit code. Thus, new area codes were allotted; for example, the area code given to Alabama was 334, for Washington was 360, and so on.[6]


ICANN is reviewing the functions and structure of Neustar Inc., the present North American Numbering Plan Administrator (NANPA), in order create a functional accountability structure. Neustar has been the NANPA since 1997. As NANPA, Neustar is responsible for supervising the assignment and use of NANP resources amongst NANP participants. Neustar is accountable to the Federal Communication Council (FCC) for its various decisions and measures taken as a administrator of NANP. ICANN has reviewed the procedures that Neustar uses to maintain transparency and accountability with the FCC in order to overcome its own issues with transparency and accountability.[7]