Area codes 408 and 669

Area codes 408 and 669 are telephone area codes in the North American Numbering Plan (NANP) in the U.S. state of California. The numbering plan area comprises most of Santa Clara County and Northern Santa Cruz County, and includes Gilroy, Morgan Hill, Saratoga, Los Gatos, Monte Sereno, Milpitas, Sunnyvale, Santa Clara, Cupertino, Campbell, and San Jose.

Area code 408 was split from area code 415 in 1959. The numbering plan area was reduced in geographic extent in 1998 for the creation of area code 831. In 2012, area code 669 was assigned as a second area code for same numbering plan area by overlay.

In 1947, the American Telephone and Telegraph Company (AT&T) devised the first nationwide telephone numbering plan and assigned the original North American area codes. The state of California was divided into three numbering plan areas (NPAs) with distinct area codes: 213, 415, and 916, for the southern, central, and northern parts of the state, respectively. California area codes were reorganized geographically in 1950, so that 916 was assigned to a numbering plan area that comprised only the northeastern part from the Sierra Nevada to the Central Valley. The coastal area to the west was assigned area code 415.

Area code 408 was split from numbering plan area 415 in a flash-cut (without permissive dialing period) on March 1, 1959. The new numbering plan area included most of Santa Clara, Santa Cruz, Monterey and San Benito Counties.

In 1997, the California/Nevada Code Administrator (C/NCA) advised the North American Numbering Plan Administration (NANPA) of the need for area code relief in the 408 numbering plan area. A geographic area code split had been approved by the California Public Utilities Commission (CPUC) which would install area code 831 for a new numbering plan area comprising the communities of Santa Cruz, Salinas, Monterey, and Hollister. Area code 408 would be retained in Sunnyvale, San Jose, Los Gatos, and Gilroy. The area code split became effective on July 11, 1998, with a permissive dialing period ending on February 20, 1999.

Months later, by late 1998, continued growth in telecommunication services in Northern California required further area code relief for the 408 numbering plan area. A November 1998 relief plan was approved by the CPUC that proposed an overlay complex for NPA 408, with the new area code 669. However, by December 1999, the CPUC suspended the 408 overlay, along with all other then-scheduled overlay relief actions (NPAs 415, 510, 650, 714, and 909), due to the implementation of telephone number pooling, a more efficient number allocation method.

Telephone number pooling staved off exhaustion for over a decade, but by 2011, the 408 area code was forecast to require relief by the second quarter of 2012. From May to October 2011, public feedback was solicited in the area. On October 20, 2011, the California Public Utilities Commission confirmed implementing 669 as an overlay to the existing 408 numbering plan area, the first in the San Francisco Bay Area. The new area code's official in-service date was November 20, 2012, when new central office codes could be activated. A six-month permissive dialing period was conducted from April 21 to October 20 during which calls could be initiated by seven- or ten-digit dialing. Ten-digit dialing also required the prefix digit 1 (1+10-digit dialing).

AT&T telephone bills, shortly before the overlay was to go into effect, included the following information for 408 area code customers: