Room 641A

The room measures about 24 by 48 feet (7.3 by 14.6 m) and contains several racks of equipment, including a Narus STA 6400, a device designed to intercept and analyze Internet communications at very high speeds.

The Electronic Frontier Foundation (EFF) filed a class-action lawsuit against AT&T on January 31, 2006, accusing the telecommunication company of violating the law and the privacy of its customers by collaborating with the National Security Agency (NSA) in a massive, illegal program to wiretap and data-mine Americans' communications.

On July 20, 2006, a federal judge denied the government's and AT&T's motions to dismiss the case, chiefly on the ground of the state secrets privilege, allowing the lawsuit to go forward.

On August 15, 2007, the case was heard by the Ninth Circuit Court of Appeals and was dismissed on December 29, 2011, based on a retroactive grant of immunity by Congress for telecommunications companies that cooperated with the government.

After many years of litigation, on April 25, 2019, ruling from the Northern District of California for Jewel v. NSA[9] concluded that the evidence presented by the plaintiff's experts was insufficient; "the Court confirms its earlier finding that Klein cannot establish the content, function, or purpose of the secure room at the AT&T site based on his own independent knowledge."