IP Cameras
IP network security cameras use twisted pair instead of a coaxial cable and reside on a computer network. Don't confuse these cameras with web-cams because IP cameras are a totally different technology. IP cameras don't need to be connected directly to a computer for them to operate, they are an independent self contained unit.
Plug one into your LAN (Local Area Network), connect to it using it's internal IP address, configure it and you're ready to record as long as you have a storage device. Some cameras are capable of storing recorded images but to store a large amount of recorded, more than a few hours, video you will have to send the video to a storage drive. If you couple your camera with a software like MileStone, you can compress the video and retrieve stored footage like a DVR (Digital Video Recorder) allows.
Like IR cameras, the price point for IP cameras is higher than regular analog cameras so putting one of these in a typical business or residential system may not be an option. Large corporations, stadiums, colleges, airports and munipical areas are generally the leaders in implementing this type of system.