The change will affect residents of Santa Clara County and parts of Alameda and Santa Cruz counties in the 408 area code, and is occurring because a new 669 area code is being added to the region.

Known as an area code overlay, the two area codes will work together in the same South Bay region that includes much of the tech industry-heavy Silicon Valley that has just about run out of ...

The San Jose Mercury News says new phone lines from Sunnyvale to Gilroy will get a 669 area code. The state Public Utilities Commission approved the plan Thursday. The area code overlay begins in ...