The backbone behind any good digital video security system is the surveillance DVR or Digital Video Recorder. It processes the video transmissions sent by the digital video cameras, controls the video cameras, stores the recorded surveillance video footage, and transmits the real-time and recorded video images to the monitor, the internet, or some other output device. In essence, the surveillance DVR is actually the brain of the security and surveillance digital video system.
The surveillance DVR can be directly wired or cabled to the digital video cameras or the cameras can communicate with the DVR wirelessly. In many covert (hidden or disguised) digital video surveillance systems the DVR and camera are an all-in-one compact system.