Comint
Signals intelligence (often contracted to SIGINT) is intelligence-gathering by interception of signals, whether between people ("communications intelligence"—COMINT), whether involving electronic signals not directly used in communication ("electronic intelligence"—ELINT), or combinations of the two. As sensitive information is often encrypted, signals intelligence often involves the use of cryptanalysis. Also, traffic analysis—the study of who is signaling whom and in what quantity—can often produce valuable information, even when the messages themselves cannot be decrypted.
As a means of collecting intelligence, signals intelligence is a subset of intelligence collection management, which, in turn, is a subset of intelligence cycle management.
Read more about Comint: History, More Technical Definitions of SIGINT and Its Branches, COMINT, Electronic Signals Intelligence, SIGINT Versus MASINT, Defensive Signals Intelligence