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Room 641A

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Why This Matters

Room 641A is the concrete example that turned suspicions of bulk internet surveillance into documented fact: a secret AT&T facility in San Francisco where beam splitters copied backbone traffic into Narus analysis equipment. It established that telecom carriers could be enlisted to tap domestic as well as foreign communications at scale, and it set the template for later legal and political fights over network privacy.

Key Takeaways
Worth a Look

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Description [ edit ]

Room 641A is located in the SBC Communications building at 611 Folsom Street, San Francisco, three floors of which were occupied by AT&T before SBC purchased AT&T.[1] The room was referred to in internal AT&T documents as the SG3 [Study Group 3] Secure Room.

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.[1] It is fed by fiber optic lines from beam splitters installed in fiber optic trunks carrying Internet backbone traffic.[3] In the analysis of J. Scott Marcus, a former CTO for GTE and a former adviser to the Federal Communications Commission, it has access to all Internet traffic that passes through the building, and therefore "the capability to enable surveillance and analysis of internet content on a massive scale, including both overseas and purely domestic traffic."[4]

The existence of the room was revealed by former AT&T technician Mark Klein and was the subject of a 2006 class action lawsuit by the Electronic Frontier Foundation against AT&T.[5] Klein claims he was told that similar black rooms are operated at other facilities around the country.[6]

Room 641A and the controversies surrounding it were subjects of an episode of Frontline,[7] the current affairs documentary program on PBS. It was originally broadcast on May 15, 2007. It was also featured on PBS's NOW on March 14, 2008. The room was also covered in the PBS Nova episode "The Spy Factory".