Security camera systems also known as CCTV (Closed-circuit television) have evolved greatly over the years. In the old days, cameras were connected to a sequential switcher which in turn was connected to a monitor. The switcher would switch between several different cameras and the video would be recorded by a time-lapse VCR. With the invention of the multiplexer, the VCR could record all cameras at once. The time-lapse recorder could record up to twenty-four hours on one tape, requiring a daily rotation of tapes.
The recent development of digital recording provides the ability to record up to a month of 4-camera video on a DVR with an 250 gigabyte hard drive. The system can automatically record over old video so that the system does not require user intervention to operate.
The DVR does not need a sequential switcher or multiplexer to operate. In addition, the digital system can record 24 hours per day, be programmed to record at various times/intervals or can be used with motion-sensing equipment so that the system only records when someone walks into the view of the camera.
The system can also be connected to DSL, cable or other high-speed Internet access so that the cameras can be viewed from home or the office. Now, you don't have to hire security guards to watch the monitors on site.