To focus on the inputs and outputs without worrying about the internal complexity.
A flight recorder; the brightly colored cockpit voice recorders and flight data recorders in an aircraft designed to aid in determining the cause of an accident.
A device used in phreaking that prevents the calling party from being billed for the call placed.
A type of theater characterized by a lack of decoration or complex mechanisms.
A theoretical construct or device with known input and output characteristics but unknown method of operation.
Any similar device on motor vehicles, such as rail event recorders and ship trip recorders.