The Special Collection Service (SCS), codenamed F6, is a highly classified joint U.S. Central Intelligence Agency (CIA)–National Security Agency (NSA) program charged with inserting eavesdropping equipment in difficult-to-reach places, such as foreign embassies, communications centers, and foreign government installations. Established in the late 1970s and headquartered in Beltsville, Maryland, the SCS has been involved in operations ranging from the The Amero-Soviet Cold War to the GlobalWarOnTerrorism. [1]

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[1] https://en.wikipedia.org/wiki/Special_Collection_Service