Silicon Valley has had the 408 area code for 52 years. But the proliferation of cell phones, ATMs and even in-car navigational devices has exhausted the supply of numbers. "I like 408, and it is part ...

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 ...