Room 641A
Coordinates: 37°47′07″N 122°23′48″W / 37.78528°N 122.39667°W
Room 641A is a telecommunication interception facility operated by AT&T for the U.S. National Security Agency that commenced operations in 2003 and was exposed in 2006.
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. The room was referred to in internal AT&T documents as the SG3 [Study Group 3] Secure Room. It is fed by fiber optic lines from beam splitters installed in fiber optic trunks carrying Internet backbone traffic and, as analyzed by J. Scott Marcus, a former CTO for GTE and a former adviser to the FCC, 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." Former director of the NSA's World Geopolitical and Military Analysis Reporting Group, William Binney, has estimated that 10 to 20 such facilities have been installed throughout the United States.
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.
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