<a href="http://www.digitaldirectsecurity.co.uk/cctv-system-kits/cctv-system-kits.html">CCTV systems</a> generally include one or more cameras, a receiver, a transmitter, a recorder and a monitor. Sometimes, several of these units are packed into a single device. However, they all work on the same principle of recording images, transmitting these to your monitor and then sending them out to be recorded.