Introduction to CCTV
Closed Circuit Television (CCTV) is a system where the circuit in which the video is transmitted is closed and all the elements (camera, display monitors, recording devices) are directly connected.
This is unlike broadcast television where any receiver that is correctly tuned can pick up and display or store the signal.
Such specialised systems are not subject to regulation by the Federal Communications Commission (FCC) however, security cameras using scrambled radio waves are in fact subject to common carrier tariffs and FCC conditions of service.
In the past, these signals would be transmitted to a monitor equipped with a video cassette recorder, but these have been all but totally replaced by digital video recorder (DVR) systems that can store far more video and back up data automatically.
CCTV Cameras
Any camera that broadcasts a signal can be attached to a CCTV system, whether it’s wired or wireless, but they are most often associated with high-end surveillance cameras. Pan-tilt and zoom cameras allow a user to remotely control a camera. The type of lens used will depend on the application and area the camera will be installed.
Fixed aperture lenses cannot be adjusted for distance or lighting considerations. Lower in cost than other lenses, these are usually sufficient for indoor installations where lighting will be consistent.
There are two types of adjustable iris lenses. Manual iris lenses can be adjusted for changes in lighting conditions, but it must be done manually. Auto iris camera lenses can sense changes in lighting in the area they observe and will automatically make adjustments so they provide the best picture possible.
These are usually the best choice for outdoor installations. Manual zoom lenses allow you to adjust the focus area on a camera by hand. If you want to be able to change focus remotely, motorised zoom lenses are also available, but more costly.
What is CCTV Used For?
The most common use of CCTV is in security camera systems.
They’ve been found for years in areas like large retail shops, banks, and government institutions.
Thanks to reduced costs in the manufacture of cameras and video recording equipment, camera systems are becoming more and more common place in smaller businesses, and even private homes.
Other Uses For CCTV
CCTV has become almost obligatory in schools both primary and secondary as well as colleges and universities.
Retail parks, utility suppliers and most commercial sites of all descriptions employ CCTV, not only for security but health and safety.