Signals intelligence
![RAF Menwith Hill, a large site in the United Kingdom, part of ECHELON and the UKUSA Agreement, 2005](/Images/godic/202502/21/Menwith-hill-radomes3231.jpg")
![The last German message intercepted by the British during World War II, signaling Germany's unconditional surrender](/Images/godic/202502/21/Bletchley_Park_last_German_intercept3231.JPG")
![Zimmermann telegram, as decoded by Room 40 in 1917.](/Images/godic/202502/21/Ztel23231.jpg")
![A Mark 2 Colossus computer. The ten Colossi were the world's first programmable electronic computers, and were built to break the German codes.](/Images/godic/202502/21/Colossus3232.jpg")
Signals intelligence (SIGINT) is intelligence-gathering by interception of signals, whether communications between people (communications intelligence—abbreviated to COMINT) or from electronic signals not directly used in communication (electronic intelligence—abbreviated to ELINT). Signals intelligence is a subset of intelligence collection management.