AT&T Provided NSA with Decades of Domestic Call Records Through Room 641A

When Mark Klein walked into the offices of the Electronic Frontier Foundation in 2006, he carried documents that would challenge everything Americans believed about their phone calls and internet privacy. The AT&T technician had discovered something extraordinary hidden inside a nondescript San Francisco facility: Room 641A, where the National Security Agency was quietly copying decades of domestic communications.

Klein's claim was straightforward but stunning. Starting in 2003, AT&T had secretly installed NSA surveillance equipment at its switching center on Folsom Street. Fiber-optic splitters—tiny devices that divide data streams—were copying not just phone records, but the full content of internet traffic passing through AT&T's network. Millions of Americans had no idea their emails, web browsing, and digital communications were being diverted to government servers.

The official response came swiftly and dismissive. AT&T and government representatives insisted the program was necessary for national security. They characterized it as lawful cooperation with intelligence agencies and suggested that only calls involving suspected terrorists were monitored. The company refused to publicly acknowledge the arrangement. The Bush administration claimed executive authority to conduct such surveillance without warrants, arguing that post-9/11 security concerns justified the practice.

But Klein kept detailed records. He documented the equipment specifications, the installation timelines, and the scale of the operation. Before leaving AT&T, he photographed technical documents and took notes on meetings discussing "government access." These materials eventually became the backbone of the EFF's legal challenge to the program. What made Klein's evidence particularly credible was his position: he wasn't a disgruntled low-level employee but a senior technician with direct access to the facility's inner workings.