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Area codes 410, 443, and 667

November 18, 2023

Area codes 410, 443, and 667 are telephone area codes in the North American Numbering Plan (NANP) for the eastern half of the U.S. state of Maryland. The numbering plan area (NPA) includes the Baltimore metropolitan area and the Eastern Shore. The three area codes are overlay codes for one numbering plan area, among which 410 was the initial area code for the NPA, when it was split from area code 301 in 1991. 443 and 667 found assignment primarily in cellular service and for competitive local exchange carriers, such as Comcast and Cavalier Telephone, when introduced, but have since become universal in carrier availability.

Area codes 215, 267, and 445Area code 856Area code 484Area code 717Area code 814Area code 724Area code 202Area code 571Area codes 757 and 948Area code 302Area codes 410, 443, and 667Area code 304/681Area code 804Area code 434Area code 540
Maryland consists of the red and blue areas. The red area has area codes 227, 240 and 301.

History edit

In 1947, the American Telephone and Telegraph Company (AT&T) published the first configuration of a nationwide telephone numbering plan for Operator Toll Dialing, which designated the state of Maryland as a numbering plan area and assigned area code 301.[1] Despite the state being home to two large metropolitan areas, Baltimore and the Maryland suburbs of Washington, D.C. (area code 202), the state received only one area code. This made Maryland one of the most-populous states to be served by a single area code. By the late 1980s, the rapid growth of the Baltimore and Washington suburbs, as well as the proliferation of fax machines and pagers placed the numbering resources in the danger of exhaustion of central office prefixes.

The number shortage problem was exacerbated by the use of area code 202 as a de facto overlay for the inner ring of the Washington metro area, even though it was split between three area codes–301, 202, and Northern Virginia's 703. This was accomplished via a system of central office code protection in which no central office code was duplicated in multiple area codes in the region. Each existing central office code was routed with each area code in the region so that each telephone number in the region could be dialed with any of the regional area codes. The consequence was that the full capacity of central office prefixes could not be used for each involved area code.

The office code protection ended in 1990, but it soon became apparent that this would not free up enough prefixes to meet demand. By the fall of 1990, it was apparent that Maryland needed another area code. In November 1990, a plan for a second area code, 410, was announced, that would be assigned to the Baltimore metropolitan area and the Eastern Shore. new area code, while western and southern Maryland, including the Washington suburbs, would retain area code 301.[2] Bell Atlantic (now Verizon), the largest telephone provider in the region, allowed the western part of the state to retain 301 to keep the large number of federal agencies on the Maryland side of the Washington area from having to change telephone numbers. On the other side of the Potomac River, many of the same factors resulted in most of the old 703 territory outside of Northern Virginia split off as area code 540 in 1995. While Maryland would have needed a second area code at some point due to rapid growth in the Washington and Baltimore suburbs, it is very likely that the immediate need for another area code would have been staved off had it been possible to assign more 301 numbers to the Baltimore area before 1990.

Area code 410 officially entered service on October 6, 1991; it was initially implemented in a permissive-dialing phase, with ten-digit dialing for local calls across the new 301/410 boundary. The split largely followed metro lines. However, slivers of Anne Arundel and Carroll counties, as well as much of western Howard County, stayed in 301 even though these counties reckoned as part of the Baltimore area. Conversely, slivers of Frederick County, a Washington exurb, switched to 410.[3][a] Effective November 1, 1991, ten-digit dialing was required when calling a different area code in Maryland.[4]

Although the split was intended to be a long-term solution, within five years 410 was already close to exhaustion due to the proliferation of cell phones and pagers, particularly in and around Baltimore. To solve this problem, area code 443 was overlaid onto the 410 territory on July 1, 1997. Overlays were a new concept at the time, and had met resistance because of the requirement for ten-digit dialing. However, the alternative would have been a split that would have forced residents of either Baltimore or the Eastern Shore to change their numbers for the second time in a decade.

By 2011, the 410/443 area was once again running out of numbers because of the continued proliferation of cell phones. To spare residents another number change to a new area code, a third overlay code, area code 667, was implemented on March 24, 2012.[5] This had the effect of assigning 24 million numbers to just over four million people. Based on current projections, a fourth area code will not be required in the region until about 2030.[6]

Coverage edit

The counties served by these area codes include:

Notes edit

  1. ^ a b c Four counties were split between area code 301 and 410.
    • Anne Arundel County was assigned area code 410, except Laurel exchanges 210, 317, 490, 497, 498, 596, 604, 725, and 778, Marlboro exchange 952, and Fort Meade exchange 677.
    • Carroll County was assigned area code 410, except Mount Airy exchange 829 remained area code 301.
    • Howard County was assigned area code 410, except Mount Airy exchange 829 and Laurel exchanges 210, 317, 490, 497, 598, 604, 725, and 776 remained area code 301.
    • Frederick County remained area code 301, except Union Bridge exchange 775 and New Windsor exchange 635 was assigned 410.[3]

References edit

  1. ^ Mabbs, Ralph (Winter 1947–1948). "Nation-Wide Operator Toll Dialing—the Coming Way". Bell Telephone Magazine. 26 (4): 181. Retrieved July 20, 2023.
  2. ^ "New area code coming". The Baltimore Sun. November 21, 1990. p. E6.
  3. ^ a b "New area code for eastern Maryland". The Baltimore Sun. November 1, 1991. p. 1A.
  4. ^ "Now Area Codes Count in Md." The Washington Post. November 2, 1992. p. B9.
  5. ^ Fazeli Fard, Maggie (October 12, 2011). "Maryland's new 667 area code goes into effect in 2012". The Washington Post. Retrieved July 23, 2012.
  6. ^ "2022-1 NRUF and NPA Exhaust Analysis" (PDF). nationalnanpa.com. April 2022. (PDF) from the original on October 9, 2022. Retrieved November 30, 2022.

External links edit

  • NANPA area code map of Maryland
  • List of cities covered and exchanges from Area-Codes.com, 410 Area Code
  • List of cities covered and exchanges from Area-Codes.com, 443 Area Code
Maryland area codes: 227/240/301, 410/443/667
North: 717/223, 484/610/835
West: 301/240 410/443/667 East: 302, Atlantic Ocean
South: 757/948
Delaware area codes: 302
Pennsylvania area codes: 215/267/445, 223/717, 272/570, 412, 484/610, 724, 814/582, 878
Virginia area codes: 276, 434, 540, 571/703, 757/948, 804

November 18, 2023
area, codes, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, september, 201. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Area codes 410 443 and 667 news newspapers books scholar JSTOR September 2013 Learn how and when to remove this template message Area codes 410 443 and 667 are telephone area codes in the North American Numbering Plan NANP for the eastern half of the U S state of Maryland The numbering plan area NPA includes the Baltimore metropolitan area and the Eastern Shore The three area codes are overlay codes for one numbering plan area among which 410 was the initial area code for the NPA when it was split from area code 301 in 1991 443 and 667 found assignment primarily in cellular service and for competitive local exchange carriers such as Comcast and Cavalier Telephone when introduced but have since become universal in carrier availability Maryland consists of the red and blue areas The red area has area codes 227 240 and 301 Contents 1 History 2 Coverage 3 Notes 4 References 5 External linksHistory editIn 1947 the American Telephone and Telegraph Company AT amp T published the first configuration of a nationwide telephone numbering plan for Operator Toll Dialing which designated the state of Maryland as a numbering plan area and assigned area code 301 1 Despite the state being home to two large metropolitan areas Baltimore and the Maryland suburbs of Washington D C area code 202 the state received only one area code This made Maryland one of the most populous states to be served by a single area code By the late 1980s the rapid growth of the Baltimore and Washington suburbs as well as the proliferation of fax machines and pagers placed the numbering resources in the danger of exhaustion of central office prefixes The number shortage problem was exacerbated by the use of area code 202 as a de facto overlay for the inner ring of the Washington metro area even though it was split between three area codes 301 202 and Northern Virginia s 703 This was accomplished via a system of central office code protection in which no central office code was duplicated in multiple area codes in the region Each existing central office code was routed with each area code in the region so that each telephone number in the region could be dialed with any of the regional area codes The consequence was that the full capacity of central office prefixes could not be used for each involved area code The office code protection ended in 1990 but it soon became apparent that this would not free up enough prefixes to meet demand By the fall of 1990 it was apparent that Maryland needed another area code In November 1990 a plan for a second area code 410 was announced that would be assigned to the Baltimore metropolitan area and the Eastern Shore new area code while western and southern Maryland including the Washington suburbs would retain area code 301 2 Bell Atlantic now Verizon the largest telephone provider in the region allowed the western part of the state to retain 301 to keep the large number of federal agencies on the Maryland side of the Washington area from having to change telephone numbers On the other side of the Potomac River many of the same factors resulted in most of the old 703 territory outside of Northern Virginia split off as area code 540 in 1995 While Maryland would have needed a second area code at some point due to rapid growth in the Washington and Baltimore suburbs it is very likely that the immediate need for another area code would have been staved off had it been possible to assign more 301 numbers to the Baltimore area before 1990 Area code 410 officially entered service on October 6 1991 it was initially implemented in a permissive dialing phase with ten digit dialing for local calls across the new 301 410 boundary The split largely followed metro lines However slivers of Anne Arundel and Carroll counties as well as much of western Howard County stayed in 301 even though these counties reckoned as part of the Baltimore area Conversely slivers of Frederick County a Washington exurb switched to 410 3 a Effective November 1 1991 ten digit dialing was required when calling a different area code in Maryland 4 Although the split was intended to be a long term solution within five years 410 was already close to exhaustion due to the proliferation of cell phones and pagers particularly in and around Baltimore To solve this problem area code 443 was overlaid onto the 410 territory on July 1 1997 Overlays were a new concept at the time and had met resistance because of the requirement for ten digit dialing However the alternative would have been a split that would have forced residents of either Baltimore or the Eastern Shore to change their numbers for the second time in a decade By 2011 the 410 443 area was once again running out of numbers because of the continued proliferation of cell phones To spare residents another number change to a new area code a third overlay code area code 667 was implemented on March 24 2012 5 This had the effect of assigning 24 million numbers to just over four million people Based on current projections a fourth area code will not be required in the region until about 2030 6 Coverage editThe counties served by these area codes include In the Baltimore metropolitan area All of Baltimore City and Baltimore Calvert and Harford counties Most of Anne Arundel Carroll and Howard counties a A small portion of eastern Frederick County a All of Maryland s Eastern Shore Caroline County Cecil County Dorchester County Kent County Queen Anne s County Somerset County Talbot County Wicomico County Worcester CountyNotes edit a b c Four counties were split between area code 301 and 410 Anne Arundel County was assigned area code 410 except Laurel exchanges 210 317 490 497 498 596 604 725 and 778 Marlboro exchange 952 and Fort Meade exchange 677 Carroll County was assigned area code 410 except Mount Airy exchange 829 remained area code 301 Howard County was assigned area code 410 except Mount Airy exchange 829 and Laurel exchanges 210 317 490 497 598 604 725 and 776 remained area code 301 Frederick County remained area code 301 except Union Bridge exchange 775 and New Windsor exchange 635 was assigned 410 3 References edit Mabbs Ralph Winter 1947 1948 Nation Wide Operator Toll Dialing the Coming Way Bell Telephone Magazine 26 4 181 Retrieved July 20 2023 New area code coming The Baltimore Sun November 21 1990 p E6 a b New area code for eastern Maryland The Baltimore Sun November 1 1991 p 1A Now Area Codes Count in Md The Washington Post November 2 1992 p B9 Fazeli Fard Maggie October 12 2011 Maryland s new 667 area code goes into effect in 2012 The Washington Post Retrieved July 23 2012 2022 1 NRUF and NPA Exhaust Analysis PDF nationalnanpa com April 2022 Archived PDF from the original on October 9 2022 Retrieved November 30 2022 External links editNANPA area code map of Maryland List of cities covered and exchanges from Area Codes com 410 Area Code List of cities covered and exchanges from Area Codes com 443 Area CodeMaryland area codes 227 240 301 410 443 667 North 717 223 484 610 835West 301 240 410 443 667 East 302 Atlantic OceanSouth 757 948Delaware area codes 302Pennsylvania area codes 215 267 445 223 717 272 570 412 484 610 724 814 582 878Virginia area codes 276 434 540 571 703 757 948 804 Retrieved from https en wikipedia org w index php title Area codes 410 443 and 667 amp oldid 1166293845, wikipedia, wiki, book, books, library,

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