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Direct Distance Dialing
Direct distance dialing (DDD) is a telecommunication service feature in North America by which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits 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-digit directory number. Local telephone numbers still consisted of the first two letters of the central office name and five digits. On ...
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Telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the human voice, but with a similar scale of expediency; thus, slow systems (such as postal mail) are excluded from the field. The transmission media in telecommunication have evolved through numerous stages of technology, from beacons and other visual signals (such as smoke signals, semaphore telegraphs, signal flags, and optical heliographs), to electrical cable and electromagnetic radiation, including light. Such transmission paths are often divided into communication channels, which afford the advantages of multiplexing multiple concurrent communication sessions. ''Telecommunication'' is often used in its plural form. Other examples of pre-modern long-distance communication included audio messages, such as coded d ...
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Chicago
(''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name = United States , subdivision_type1 = State , subdivision_type2 = Counties , subdivision_name1 = Illinois , subdivision_name2 = Cook and DuPage , established_title = Settled , established_date = , established_title2 = Incorporated (city) , established_date2 = , founder = Jean Baptiste Point du Sable , government_type = Mayor–council , governing_body = Chicago City Council , leader_title = Mayor , leader_name = Lori Lightfoot ( D) , leader_title1 = City Clerk , leader_name1 = Anna Valencia ( D) , unit_pref = Imperial , area_footnotes = , area_total ...
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Area Code 401
Area code 401 is the sole telephone area code of Rhode Island. 401 is one of the original 86 North American area codes, which were created in 1947. Rhode Island is among the 12 U.S. states or North American jurisdictions with only one area code. The 401 area code is not projected to be exhausted until 2053.https://www.nationalnanpa.com/reports/October%202021%20NPA%20Exhaust%20Analysis.pdf See also * References 401 401 __NOTOC__ Year 401 ( CDI) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Vincentius and Fravitus (or, less frequently, year 1154 ' ... Telecommunications-related introductions in 1947 {{RhodeIsland-stub ...
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Pittsburgh
Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylvania behind Philadelphia, and the 68th-largest city in the U.S. with a population of 302,971 as of the 2020 census. The city anchors the Pittsburgh metropolitan area of Western Pennsylvania; its population of 2.37 million is the largest in both the Ohio Valley and Appalachia, the second-largest in Pennsylvania, and the 27th-largest in the U.S. It is the principal city of the greater Pittsburgh–New Castle–Weirton combined statistical area that extends into Ohio and West Virginia. Pittsburgh is located in southwest Pennsylvania at the confluence of the Allegheny River and the Monongahela River, which combine to form the Ohio River. Pittsburgh is known both as "the Steel City" for its more than 300 steel-related businesses and as the ...
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Area Code 412
Area code 412 is a telephone area code in the North American Numbering Plan (NANP) for the Commonwealth of Pennsylvania. The numbering plan area (NPA) comprises the city of Pittsburgh, most of surrounding Allegheny County, and small portions of Washington and Westmoreland counties. The area code was one of the original North American area codes created in 1947, when it was assigned to the entire southwestern corner of the state. History When the American Telephone and Telegraph Company (AT&T) created the first nationwide telephone numbering plan for the continental United States and Canada in 1947, Pennsylvania was divided into four numbering plan areas. Area code 412 was assigned to the southwestern part of the state, from Butler County to the West Virginia border. On February 1, 1998, nearly all of the old 412 territory outside of Allegheny County was split off and received area code 724, surrounding 412. Bell Atlantic, the main telephone provider at the time in Pennsylvania, ...
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Philadelphia
Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic (United States), Mid-Atlantic regions after New York City. Act of Consolidation, 1854, Since 1854, the city has been coextensive with Philadelphia County, Pennsylvania, Philadelphia County, the List of counties in Pennsylvania, most populous county in Pennsylvania and the urban core of the Delaware Valley, the Metropolitan statistical area, nation's seventh-largest and one of List of largest cities, world's largest metropolitan regions, with 6.245 million residents . The city's population at the 2020 United States census, 2020 census was 1,603,797, and over 56 million people live within of Philadelphia. Philadelphia was founded in 1682 by William Penn, ...
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Area Code 215
Year 215 ( CCXV) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Laetus and Sulla (or, less frequently, year 968 '' Ab urbe condita''). The denomination 215 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Caracalla's troops massacre the population of Alexandria, Egypt, beginning with the leading citizens. The emperor is angry about a satire, produced in Alexandria, mocking his claim that he killed Geta in self-defense. * Caracalla introduces a new coin, the Antoninianus. The weight of this coin is a mere 1/50 of a pound. Copper disappears gradually, and by the middle of the third century, with Rome's economy in crisis, the Antonianus will be the only official currency. China * Zhang Liao holds off Sun Quan's invasion force a ...
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Oakland, California
Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast of the United States, West Coast port, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the Bay Area and the List of largest California cities by population, eighth most populated city in California. With a population of 440,646 in 2020, it serves as the Bay Area's trade center and economic engine: the Port of Oakland is the busiest port in Northern California, and the fifth busiest in the United States of America. An act to municipal corporation, incorporate the city was passed on May 4, 1852, and incorporation was later approved on March 25, 1854. Oakland is a charter city. Oakland's territory covers what was once a mosaic of California coastal prairie, California coastal terrace prairie, oak woodland, and north coastal scrub. In the late 18th century, it became part of a large ''rancho'' grant in t ...
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Area Code 415
Area codes 415 and 628 are telephone area codes in the North American Numbering Plan (NANP) for the city of San Francisco and its northern suburbs in Marin County (across the Golden Gate), and the northeast corner of San Mateo County in the U.S. state of California. Area code 415 was one of the eighty-six original North American area codes established in 1947, but modified in geographic configuration later. Area code 628 was assigned in 2015 to form an overlay in that numbering plan area in mitigation of central office prefix exhaustion. History When the North American Numbering Plan was installed by AT&T for Operator Toll Dialing in 1947, the state of California was divided into three numbering plan areas (NPAs) arranged as geographical zones in the southern part, the central part, and the northern part of the state. Area code 415 was assigned to central California, south of area code 916, and north of area code 213. It stretched from Sacramento in the north to Bakersfield in the ...
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Milwaukee
Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee is the 31st largest city in the United States, the fifth-largest city in the Midwestern United States, and the second largest city on Lake Michigan's shore behind Chicago. It is the main cultural and economic center of the Milwaukee metropolitan area, the fourth-most densely populated metropolitan area in the Midwest. Milwaukee is considered a global city, categorized as "Gamma minus" by the Globalization and World Cities Research Network, with a regional GDP of over $102 billion in 2020. Today, Milwaukee is one of the most ethnically and culturally diverse cities in the U.S. However, it continues to be one of the most racially segregated, largely as a result of early-20th-century redlining. Its history was heavily influ ...
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Area Code 414
Area code 414 is a telephone area code of the North American Numbering Plan for the area around and including the city of Milwaukee in the state of Wisconsin. The area code was created in October 1947, along with area code 715, as one of the two original area codes assigned to Wisconsin. The numbering plan area (NPA) originally included most of the southern and northeastern parts of Wisconsin, stretching from Lake Michigan to the Minnesota and Iowa borders. 715, then as now, covered the remaining northwestern part. The numbering plan area was first split in 1955, when much of the western portion, including Madison, received area code 608. This configuration remained in place until July 26, 1997, when the northern half of NPA 414, including Green Bay and the Fox River Valley, became numbering plan area 920. The creation of 920 was intended as a long-term solution, but within a year 414 was close to exhaustion once again due to the proliferation of cell phones and pagers. In ...
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Detroit
Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at the 2020 census, making it the 27th-most populous city in the United States. The metropolitan area, known as Metro Detroit, is home to 4.3 million people, making it the second-largest in the Midwest after the Chicago metropolitan area, and the 14th-largest in the United States. Regarded as a major cultural center, Detroit is known for its contributions to music, art, architecture and design, in addition to its historical automotive background. '' Time'' named Detroit as one of the fifty World's Greatest Places of 2022 to explore. Detroit is a major port on the Detroit River, one of the four major straits that connect the Great Lakes system to the Saint Lawrence Seaway. The City of Detroit anchors the second-largest regional eco ...
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