Closed circuit television (CCTV):

Flying Scotsman · Feb 24, 2008

CCTV Warning Sign

CCTV is a collection of video cameras used for video surveillance.

It is different from broadcast television as all the equipment is directly connected together with cables or wireless transmitters that can not be received by standard television aerials or equipment.

The transmission of the video signals are only intended to be accessible by the equipment on its dedicated closed circuit.

CCTV is generally used in areas where there is an increased need for security, such as banks, airports and town centres. CCTV was initially developed as a means to increase security for banks but over time it has developed into a cost effective means of general surveillance and home security.

A basic CCTV system comprises of the following;

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Camera, lens and power supply.

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Recording device, VCR or a digital video recorder.

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A monitor.

Cameras:

CCTV Camera

Cameras are available in colour, monochrome or cameras that have the ability to switch between colour and monochrome (day/night cameras). The cameras that switch between colour and monochrome are intended for environments of low lighting at various times. There are 2 reasons for using a camera that can switch between colour and monochrome; monochrome cameras are much more sensitive to low lighting environments, and monochrome cameras can also be used with Infra red lighting. When there is adequate available light there is the added advantage of using a colour camera for recording colour information, for example the colour of a car or a person

Flying Scotsman · Feb 24, 2008

Remote CCTV:

Remote CCTV is the means of accessing CCTV images over a computer network or standard telephone networks. Software is used on the local PC that allows access to the digital video recorder.

IP CCTV:

IP CCTV refers to Internet Protocol Closed Circuit Television; traditional CCTV systems use digital or analogue cameras using analogue cables that connect to a recording device such as a digital video recorder. IP cameras are designed to plug onto any existing wired or wireless computer TCP/IP network, or directly onto a broadband connection so that the camera can be accessed by any computer connected to the network, this includes over the internet.

Computers are used on the network to store the camera images but with the flexibility of IP CCTV, the cameras could be located on opposite sides of the world. Although IP Cameras can be connected directly to an existing network, bandwidth is always a consideration as the data sent from the camera is likely to be much larger than standard data transferred over usual office networks which if not planned correctly can slow down the entire network.

Video Signal:

The video signal is known as the moving image information signal produced from a video camera, In the UK we use a video signal standard called PAL (Phase Alternate Line) this is a colour or monochrome video signal that comprises of 25 images or frames per second. The PAL video signal is common to most UK TV