Search results
Results From The WOW.Com Content Network
Numbering plan area code The first NYX block is the numbering plan area code. When the second and third digits are the same, the code is an easily recognizable code (ERC). ERCs designate special services; e.g., 800 for toll-free service. The NANP is not assigning area codes with 9 as the second digit. [35]
In 1947, the American Telephone and Telegraph Company (AT&T) devised the first nationwide telephone numbering plan and assigned the original North American area codes. The state of California was divided into three numbering plan areas (NPAs) with distinct area codes: 213, 415, and 916, for the southern, central, and northern parts of the state ...
Telephone numbers listed in 1920 in New York City having three-letter exchange prefixes. In the United States, the most-populous cities, such as New York City, Philadelphia, Boston, and Chicago, initially implemented dial service with telephone numbers consisting of three letters and four digits (3L-4N) according to a system developed by W. G. Blauvelt of AT&T in 1917. [1]
A closed numbering plan, as found in North America, features fixed-length area codes and local numbers, while an open numbering plan has a variance in the length of the area code, local number, or both of a telephone number assigned to a subscriber line. The latter type developed predominantly in Europe.
Toll-free telephone numbers in the North American Numbering Plan have the area code prefix 800, 833, 844, 855, 866, 877, and 888. Additionally, area codes 822, 880 through 887, and 889 are reserved for toll-free use in the future. 811 is excluded because it is a special dialing code in the group NXX for various other purposes.
Even though trunk code is not needed for calls within the same geographical area, recent convention adds the default trunk code to the phone number notation: 8 (AAAA) BB-BB-BB. For mandatory area code dealing plans, notation 8 AAAA BB-BB-BB is used. These formats are a mix of Microsoft format and E.123 local notation.
Map of LATAs in the US. Local access and transport area (LATA) is a term used in U.S. telecommunications regulation.It represents a geographical area of the United States under the terms of the Modification of Final Judgment (MFJ) entered by the United States District Court for the District of Columbia in Civil Action number 82-0192 or any other geographic area designated as a LATA in the ...
The dialing procedures (dialing plan) in some areas permit dialing numbers in the local calling area without using an area code or city code prefix. For example, a telephone number in North America consists of a three-digit area code, a three-digit central office code, and four digits for the line number.