In the analog CCTV application, security cameras capture an analog signal and transfer that signal over cable to the Digital Video Recorder (DVR).
Each camera may be powered by plugging in the power supply at the camera or by cable, which bundles the video, and the power cables.
The DVR converts the analog signal to digital, compresses it and then stores it on a hard drive for later retrieval. Intelligence is built into the DVR to handle such things as scheduling, motion detection and digital zoom.
Monitors for viewing the video are connected to the DVR or it can be set up to publish over an internal network for viewing on PCs. The DVR can also be set up to broadcast over the Internet can be password protected and includes many other features.