Area code 669 is an overlay of the 408 area code, serving Silicon Valley cities like San Jose, Cupertino, Campbell, and Gilroy. Introduced in 2012, 669 was implemented due to the exhaustion of available numbers in the booming tech-heavy 408 region. The combined 408/669 area includes major tech headquarters such as Apple, Cisco, and eBay, and is considered the epicenter of global technological innovation. With the overlay, residents and businesses must use ten-digit dialing, but both codes coexist throughout the same region. While 408 retains historical recognition, 669 has become increasingly common with new phone lines and mobile devices. The code symbolizes the modern growth and future-facing development of Silicon Valley. Its presence underscores the ongoing digital expansion of one of the world’s most important economic zones.