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Interchangeable NPA And Central Office Codes
In the North American Numbering Plan (NANP), interchangeable NPA and central office codes constituted a change in numbering plan design and policy, to mitigate exhaustion of the numbering resources of the ten-digit telephone numbers used in the closed numbering plan of the NANP. Interchangeable numbering plan area (NPA) codes and central office codes are codes that permit any of the ten numerals in the middle position of the area code and the central office code, which both are three-digit numbers.AT&T Network Planning Division, ''Notes on the Network'', Section 2 (1980) This change in numbering format was implemented first for central office codes by 1973, which eliminated the restriction in the middle digit (''2'' to ''9'') to also permit ''0'' and ''1''. The middle position of the area code could only be ''0'' and ''1''. In 1995, this restriction for area codes was lifted as well, creating interchangeable NPA codes. History and background The ten-digit telephone numbers of the N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North American Numbering Plan
The North American Numbering Plan (NANP) is an integrated telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1, World Numbering Zone 1 and has the telephone country code, country code ''1''. Some North American countries, most notably Telephone numbers in Mexico, Mexico, do not participate in the NANP. The concepts of the NANP were devised originally during the 1940s by the American Telephone and Telegraph Company (AT&T) for the Bell System and the independent telephone companies in North America in Operator Toll Dialing. The first task was to unify the diverse local telephone numbering plans that had been established during the preceding decades, with the goal to speed call completion times and decrease the costs for long-distance calling, by reducing manual labor by switchboard operators. Eventually, it prepared the continent for direct-dialing of long-distance calls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Closed Numbering Plan
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined world-wide, as well as within each of the administrative regions of the public switched telephone network (PSTN), and in private telephone networks. In public numbering systems, geographic location typically plays a role in the sequence of numbers assigned to each telephone subscriber. Many numbering plan administrators subdivide their territory of service into geographic regions designated by a prefix, often called an area code or city code, which is a set of digits forming the most-significant part of the dialing sequence to reach a telephone subscriber. Within such regions designated by area codes, locally unique telephone number are assigned based on lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Code
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined world-wide, as well as within each of the administrative regions of the public switched telephone network (PSTN), and in private telephone networks. In public numbering systems, geographic location typically plays a role in the sequence of numbers assigned to each telephone subscriber. Many numbering plan administrators subdivide their territory of service into geographic regions designated by a prefix, often called an area code or city code, which is a set of digits forming the most-significant part of the dialing sequence to reach a telephone subscriber. Within such regions designated by area codes, locally unique telephone number are assigned based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seven-digit Dialing
Seven-digit dialing is a telephone dialing procedure customary in some territories of the North American Numbering Plan (NANP) for dialing telephone numbers in the same numbering plan area (NPA). NANP telephone numbers consist of ten digits, of which the leading three are the area code. In seven-digit dialing it is not necessary to dial the area code. The procedure is also sometimes known as ''local format'' or ''network format''. History Originally, telephone exchanges consisted of manual switchboards operated by switchboard operators. Telephone numbers had typically two to four digits, depending on the size of the community. As the number of subscribers grew, multiple exchanges served individual neighborhoods of large cities. Multiple exchanges were identified by a central office name and typically four digits, such as "Pennsylvania 5000". A rural telephone number, often party line, had often up to four digits and a letter or letter and digits to indicate which of the multiple p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Control
In telecommunications, common control is a principle of switching telephone calls in an automatic telephone exchange that employs shared control equipment which is attached to the circuit of a call only for the duration of establishing or otherwise controlling the call. Thus, such control equipment need only be provided in as few units to satisfy overall exchange traffic, rather than being duplicated for every subscriber line. In contrast, ''direct control'' systems have subsystems for call control that are an integral part of the switching network. Strowger exchanges are usually direct control systems, whereas crossbar, and electronic exchanges (including all stored program control systems) are common control systems. Common control is also known as indirect control or register control. History Early semi-mechanical installations with common control components existed, for example rotary systems in Sweden and France in 1915, and the first panel switches in Newark, New Jerse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operator Toll Dialing
Operator Toll Dialing was a telephone call routing and toll-switching system for the Bell System and the independent telephone companies in the United States and Canada that paved the way for Direct Distance Dialing (DDD) by telephone service subscribers. Operator Toll Dialing was developed in the early 1940s for regional service and expanded nationwide by the end of the decade. It automated the switching and billing of Long-distance calling, and drastically reduced the time callers had to wait for connection completion. Historical context The concept and technology of Operator Toll Dialing evolved from the General Toll Switching Plan of 1929, and gained technical merits by the cutover of a new type of crossbar switching system (No. 4XB) in Philadelphia to commercial service in August 1943. Operator Toll Dialing was the first system of its kind for automated forwarding of calls between toll switching centers. In Pennsylvania, it had served customers only for regional toll traffic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Distance Dialing
Direct distance dialing (DDD) is a telecommunications service in North America by which a caller may call any other subscriber outside the local calling area without operator assistance, DDD was introduced in the United States in 1951, on a trial basis, with service from Englewood, New Jersey. Direct long-distance dialing by subscribers requires extra digits, called an area code, to be dialed as prefixes to the directory telephone number of the destination. International Direct Distance Dialing (IDDD) extends the system beyond the geographic boundaries of the North American Numbering Plan (NANP). History The first direct-dialed long-distance telephone calls were possible in the New Jersey communities of Englewood and Teaneck. Customers of the ENglewood 3, ENglewood 4 and TEaneck 7 exchanges, who could already dial telephone numbers in the New York City area, could place calls to eleven major cities across the United States by dialing the three-digit area code and the seven-di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strowger Switch
The Strowger switch is the first commercially successful electromechanical stepping switch telephone exchange system. It was developed by the Strowger Automatic Telephone Exchange Company founded in 1891 by Almon Brown Strowger. Based on its mechanical characteristics, it is also known as a step-by-step (SXS) switch. History Strowger, an Funeral director, undertaker, was motivated to invent an automatic telephone exchange after becoming convinced that the Telephone exchange#Manual service exchanges, manual telephone exchange operators were deliberately interfering with his calls, leading to loss of business. According to the local Bell Telephone Company manager Herman Ritterhoff, Strowger swore to "get even" with the telephone operators and "put every last one of them out of a job." Ritterhoff claimed in 1913 that the real cause of Strowger's difficulties was a metal sign hung on his wall over his telephone, causing an intermittent short circuit when blown by the wind. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Code 905
Area codes 905, 289, 365, and 742 are telephone area codes in the North American Numbering Plan (NANP) for the Golden Horseshoe region that surrounds Lake Ontario in Southern Ontario, Canada. The numbering plan area (NPA) comprises (clockwise) the Niagara Peninsula, the city of Hamilton, the regional municipalities of Halton, Peel, York, Durham, and parts of Northumberland County, but excludes the City of Toronto. The four area codes form an overlay numbering plan for the same geographic region, where area code 905 was established in October 1993 in an area code split from area code 416. When 289 was overlaid on June 9, 2001, all local calls required ten-digit dialing. On April 13, 2010, the Canadian Radio-television and Telecommunications Commission (CRTC) introduced another overlay code, area code 365, which became operational on March 25, 2013. Area code 742 was added to the overlay on October 16, 2021. The numbering plan area surrounds the city of Toronto (area codes 416/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Code 416
Area is the measure of a region's size on a surface. The area of a plane region or ''plane area'' refers to the area of a shape or planar lamina, while ''surface area'' refers to the area of an open surface or the boundary of a three-dimensional object. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat. It is the two-dimensional analogue of the length of a curve (a one-dimensional concept) or the volume of a solid (a three-dimensional concept). Two different regions may have the same area (as in squaring the circle); by synecdoche, "area" sometimes is used to refer to the region, as in a "polygonal area". The area of a shape can be measured by comparing the shape to squares of a fixed size. In the International System of Units (SI), the standard unit of area is the square metre (written as m2), which is the area of a square ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Code 334
Area code 334 is a telephone area code in the North American Numbering Plan (NANP) for southeastern Alabama. It was created on January 15, 1995, in an area code split from area code 205. It was the first new area code in Alabama since the announcement of the area code system in 1947. To permit a transition period for the reconfiguration of equipment, such as computers and fax machines, use of area code 205 continued in the 334 region through May 13, 1995. The numbering plan area (NPA) comprises the Montgomery, Alabama, Montgomery, Auburn, Alabama, Auburn-Opelika, Alabama, Opelika, and Dothan, Alabama, Dothan metropolitan areas, as well as Phenix City, Alabama, Phenix City and the Alabama side of the Columbus, Georgia metro area. The original 334 territory included the southern half of Alabama. The southwestern part of the numbering plan area was split off with Area code 251 in 2001, including Mobile, Alabama, Mobile. Area code 334 was the first interchangeable NPA code, not havin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Code 360
Area code 360 is a telephone area code in the North American Numbering Plan (NANP) for the part of Washington state outside metropolitan Seattle and west of the Cascade Mountains. The numbering plan area (NPA) serves all of western Washington outside urban King, Pierce, and Snohomish counties and Bainbridge Island, Prior to January 15, 1995, when the area code was put into service, the numbering plan area (NPA) was served by area code 206, Washington's original area code since 1947. Since 2017, the numbering plan area has been part of an overlay complex with area code 564, which also overlays 206. History From 1947 to 1957, all of Washington state was assigned area code 206 for routing long-distance telephone calls in Operator Toll Dialing. In 1957, the numbering plan area (NPA) was reduced to just Western Washington, with most of Eastern Washington (east of the Cascade Mountains) receiving area code 509. Washington remained with two NPAs for 38 years. This configurati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
