How does a CCTV surveillance system work?

The cameras send the information on the data it captures to the DVR or NVR. The video record then:

• transmits the information to the screen
• records the information on the local hard disc which resides within the video recorder.
• connects to a router which broadcasts it across the web

This broadcasting is what allows you to access your feed from any computer, iphone or Android device. Typical connection diagram of an Analog / TVI system. With a digital system, cabling will be CAT5/6 and usually no power supply to the cameras is required.