CCTV (Closed Circuit Television): This term once referred specifically to systems that worked like standard television. At the time that the term was coined (the 1960s), the cutting edge was technology that was to eventually become cable television. It used low-frequency waves sent over metal-core and braid cables to connect a video signal with a receiver. However, instead broadcasting in a way that anyone could receive it (also called Open Circuit Television) it would instead only be connected to a single source (thus “closing” the circuit). Today the term is still applicable. All security systems connect from the camera to a recorder. Even though theoretically anyone can “connect” to the signal over the internet, you are still required to have the username and password... This effectively allows the system to prevent anyone who doesn’t belong from “joining” or “connecting” to the signals, and therefore “closes” the circuit off again.