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Area code 412

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Coordinates:40°29′17″N79°53′31″W / 40.488°N 79.892°W /40.488; -79.892

From Wikipedia, the free encyclopedia

Telephone area code for Pittsburgh, Pennsylvania

Area code 412 is a telephone area code in theNorth American Numbering Plan (NANP) for theCommonwealth ofPennsylvania. The numbering plan area (NPA) comprises the city ofPittsburgh, most of surroundingAllegheny County, and small portions ofWashington andWestmoreland counties. The area code was one of theoriginal North American area codes created in 1947, when it was assigned to the entire southwestern corner of the state.^[1]On August 17, 2001, the numbering plan area was converted to anoverlay complex witharea code 878, which also forms an overlay witharea code 724, in the surroundings of the 412 service area.

History

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When theAmerican Telephone and Telegraph Company (AT&T) created the first nationwidetelephone 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, most of southwestern Pennsylvania outside of Allegheny County was split into a new numbering plan area witharea code 724.Bell Atlantic, the main telephone provider at the time in Pennsylvania, had preferred to implement 724 as anoverlay to spare residents and businesses the burden of changing telephone numbers. However, overlays were still a new concept at the time, and met with resistance because of the need forten-digit dialing. As a result, 724 was implemented as anarea code split, making 412 one of six pairs ofdoughnut area codes in North America.

This configuration was intended as a long-term solution, but within two years both 412 and 724 experienced high demand for telephone services from the proliferation of cell phones and pagers, so that further relief became necessary. By this time, overlays had gained more acceptance, soarea code 878 was implemented as an overlay for both 412 and 724 on August 17, 2001.^[2] Although telephone numbers were not assigned for 878 until 2013 (and were only assigned in the 724 area until 2015), ten-digit dialing has been mandatory across southwestern Pennsylvania since 2001.