Signals Intelligence (SIGINT or SI) is a NSA/CSS intelligence-gathering operation through wires(cables) and wireless(radio waves). It is presumably headquartered in Information Operations Technology Center (IOTC), Fort Meade, Maryland, with branches around the US, including San Antonio, Texas. NSA PRISM is a project of this 'INT'. There are 3 divisions(INT) in SIGINT * COMINT: Communications Intelligence * ELINT: Electronic Intelligence * TELINT/FISINT: Telemetry Intelligence / Foreign Instrumentation Signals Intelligence