611 Folsom Street may refer to anything of or relating to the NSA warrantless surveillance controversy and may also refer directly to: AT&T's regional switching center, San Francisco. Room 641A, located on the sixth floor at AT&T's switching center. NSA warrantless surveillance controversy. Wiretapping Mark Klein, a whistle-blower uncovering U.S. federal spying program. San Luis Obispo, data center which routed data to Folsom address.