Area codes 415 and 628

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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.

Numbering plan areas in California (blue) and border states. Area codes 415 and 628 are shown in red.

History edit

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.[1] 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 south.[2]

In 1950, the boundaries of the numbering plan area were redrawn to produce a division of the northern and central parts along a north–south-running dividing line. Numbering plan area 415 became the coastal region from the North Coast to the Oregon border, while 916 was redrawn to comprise the northeastern corner of the state.[3] As part of this realignment, Sacramento was renumbered from area code 415 to 916, and Bakersfield to 213.

With the preparations for nation-wide direct distance dialing (DDD) in the early 1950s, area code 318 was temporarily used in the San Francisco area, initially by customers in Englewood, New Jersey, participating in the first customer trials to reach the city, as well as some areas north of the Golden Gate.[4] In 1953, the entire Bay Area was "reunited" in using area code 415.

Area code 415 has been split three times due to the Bay Area's rapid economic growth and demand for telecommunication services:

On February 21, 2015, the numbering plan area was transitioned to an overlay plan by adding area code 628 to the same service area for new numbers,[9] making ten-digit dialing mandatory in the area, with eleven-digit dialing necessary from landlines.[10]

Service area edit

City and County of San Francisco edit

Marin County edit

San Mateo County edit

See also edit

References edit

  1. ^ Mabbs, Ralph I. (Winter 1947–1948). "Nation-wide Operator Toll Dialing—the Coming Way". Bell Telephone Magazine. 26 (4): 181. Retrieved 2022-12-26.
  2. ^ Madison, Linc (1999-05-27). "LincMad's 1947 Area Code Map". Archived from the original on 4 January 2007. Retrieved 2007-01-06.
  3. ^ Moore, Carl (1996-02-12). "history.of.area.splits". TELECOM Digest. Archived from the original on 10 July 2012. Retrieved 2007-01-06.
  4. ^ Cuccia, Mark (1996-08-13). "Re: When Was Direct Distance Dialing Cut In?". TELECOM Digest. Retrieved 2007-01-06.
  5. ^ Madison, Linc. "NANP Area Code History: 1948 - 1959". Archived from the original on 2002-09-11. Retrieved 2007-01-06.
  6. ^ Fabisch, M.P. (1990-06-13). "NANPA Revised Date for Split of 415 (California) Numbering Plan Area" (PDF). Bellcore Letter. Archived from the original (PDF) on 2011-06-04. Retrieved 2007-01-06.
  7. ^ "AT&T- News Room". 1998-01-28. Retrieved 2012-09-07.
  8. ^ Deak, J.N. (1996-11-22). "NANPA Revised Date for Split of 415 (California) Numbering Plan Area" (PDF). North American Numbering Plan Letter. PL-NANP-022. Archived from the original (PDF) on 2008-12-30. Retrieved 2007-01-06.
  9. ^ "415 Area Code". California Public Utilities Commission. Archived from the original on 2015-02-26. Retrieved 2015-02-25.
  10. ^ Rubenstein, Steve (2015-02-20). "415, meet 628: New S.F. area code debuts Saturday". SFGate. Retrieved 2020-04-26.

External links edit

California area codes: 209, 213/323, 279/916, 310/424, 341/510, 408/669, 415/628, 442/760, 530, 559, 562, 619/858, 626, 650, 657/714, 661, 707, 747/818, 805/820, 831, 840/909, 925, 949, 951
North: 707
West: Pacific Ocean, 808 area code 415/628 East: 510/341, 925
South: 650
Hawaii area codes: 808

38°00′N 122°36′W / 38°N 122.6°W / 38; -122.6