| CCTV stands for closed circuit television. It is a | | | | it does not have tuning circuits. |
| system where the circuit is closed and all the | | | | Simple CCTV systems consist of a camera |
| elements are linked. This is different from | | | | connected to a monitor with coaxial cable. This |
| broadcast T.V. where tuners pick up the signals | | | | cable also carries the power needed for the |
| from the airwaves. For purposes of this article, | | | | camera. This is called a line powered camera. The |
| linked means connected by wiring, microwave, | | | | Pye Observation System was such a system and |
| infrared, etc. | | | | was popular during the early days of CCTV. It |
| What's It Used For? | | | | was affordable and could be set up with a |
| The most obvious and common use for CCTV is | | | | minimum of difficulty. The next big step in the |
| for security. This type of installation is used in a | | | | technology was allowing for four cameras to be |
| variety of locations such as stores, banks, and | | | | connected to the monitor simultaneously. The |
| government buildings. However, there are so | | | | view could be programmed to cycle through the |
| many other uses. It can be used for monitoring | | | | available cameras or go to a particular camera |
| traffic. It is used in sports stadiums to focus on | | | | chosen by the user. |
| the audience. It can be hidden in trains and buses | | | | Record For Posterity |
| to detect vandalism. It can be used to monitor | | | | Another big advance was when footage could be |
| animals in a zoo. It can even be used to | | | | recorded and stored. The footage would be |
| reproduce infrared vision. The applications are | | | | played back according to the viewing cycle the |
| almost limitless. | | | | user chose. Once the footage is recorded, it |
| What's In It? | | | | cannot be changed to go to a different camera. |
| It all starts with the camera. This creates the | | | | The next step would be cameras that were able |
| picture that is transmitted to the control area. | | | | move and swivel. Simple platforms that move on |
| Most CCTV cameras are not fitted with lenses. | | | | a horizontal plane are called scanners. If a platform |
| They must be obtained separately and screwed | | | | moves on both vertical and horizontal units it is |
| on. There is a standard screw thread although | | | | called a pan, tilt unit. |
| there are different mounts. Not all lenses have | | | | The concept of CCTV is simple enough to |
| focus adjustment. Most have iris adjustment. | | | | understand. It is the application of such technology |
| Some wide angle lenses do not have a focus ring. | | | | that still holds many undiscovered gems. Such a |
| There is a BNC jack for connecting the video | | | | simple concept can be tapped for its limitless |
| cable. In the case of line powered cameras, this | | | | potential. And for the end user, it can serve as a |
| coaxial cable also provides power. The monitor is | | | | great tool to accomplish many different things. In |
| what receives the signal that the camera creates. | | | | the end, that is the most important thing. |
| A CCTV monitor is similar to a television set but | | | | |