The 760 area code was created in 1997 when it was split from the 619 area code.
In 1998 and early 1999 the NANPA convened a series of meetings, including public participation meetings, to discuss alternatives for introduction of a new area code in the 760 because new prefixes were in short supply. At the time there was no significant dispute on the merits of a split versus an overlay. The industry, as well as the public consensus was for a geographic split. There was dispute as to whether a split would provide relief for the long term. On July 8, 1999, the CPUC adopted D.99-07-017, ordering a geographic split as the means of introducing a new area code -- 442 The commission declined to adopt any additional measures for subsequent area code relief in the 760. The split boundary created a new area code for the parts of Northern San Diego county currently in the 760 and the remaining portion of the 760, Imperial, Inyo and Mono counties and parts of Riverside, San Bernardino and Kern counties would retain the 760. See Map.
On July, 20, 2000, in D.00-07-053, the CPUC subsequently suspended D.99-07-017 to explore, develop and employ more efficient means of using the numbering resource to extend the life of the 760 area code.
On October 10, 2001, the Telecommunications Division issued a report on the 760.
In 2006, NANPA informed the CPUC that the 760 was in jeopardy. A series of planning meetings were held on the 760 within the industry. Public participation meetings were held in February 2007. The public expressed a preference for a geographic split during the meetings.
NANPA filed Application 07-06-018 on June 18, 2007, recommending the industry consensus solution of an all services overlay of area code 442 for the 760. A.07-0-6-018 recommended Split Alternative 4 as the recommended solution should a geographic split be ordered.
D.08-04-058, issued April 24, 2008, split the 760 and authorized the introduction of the 442 area code. D.08-04-058 ordered localities in northern San Diego county to change their area code from 760 to 442 in May 2009.
On August 15, 2008, parties in Northern San Diego County petitioned the CPUC to modify D.08-04-958 and order an overlay as the means of introducing the new 442 area code.
On October 16, 2008, the CPUC granted the petition to modify and ordered the implementation of an all services overlay for the entire 760 area code. (D.08-10-038) The overlay was effective on October 24, 2009. At that time all customers currently using the 760 area code were required to dial 1 + 10 digits to make all telephone calls.