CCTV – An Overview

This page gives a broad overview of CCTV and some of the benefits.  It also details the basic elements of a CCTV system, and outlines the requirements of the Data Protection Act.

What is CCTV?

Most people are aware of CCTV surveillance as it are widely used commercially and in the public sector – for example, in town centres, shops and on public transport – and often featured in the media.

CCTV is an acronym for Closed Circuit Television: “closed circuit” as in an installation of directly connected components creating a circuit which cannot be viewed by anybody outside of the circuit, unlike a terrestrial television broadcast system which can be viewed by anybody with the appropriate reception equipment.

An obvious use for CCTV is to prevent crime and malpractice but it is also a valuable business management tool offering staff protection, supporting Health & Safety initiatives, aiding investigations, proving innocence and avoiding lawsuits; other examples of its use are help with production control and other observational objectives in factories where, for example, conditions are unsuitable for human intervention.  It can be used a wide range of other applications, such as traffic surveys, keeping an eye on livestock and for monitoring wildlife activity, to name but few.

The use of CCTV in the home environment is becoming more popular.  Not only does it improve general security, it can help to defend against anti social behaviour, and is a way of keeping an eye on children and pets.

CCTV systems in the public arena are governed by the Data Protection Act of 1988; those in a domestic environment are governed by the Human Rights Act.

CIA’s expert system designers and technicians tailor-make CCTV systems to suit individual requirements, from simple one camera and monitor systems to multiple camera systems that are fully integrated with other security installations.

The elements of a CCTV system

There are three basic elements to a CCTV system:

Simple CCTV System


  1. Camera
  2. Lens
  3. Monitor unit

The camera is the element which captures the image and transmits it back to a monitor. The camera needs a lens to be able to focus on the subject. There are a wide variety of lenses to suit different applications.

The monitor is the receiver unit which converts the captured image into a picture, allowing you to see it.

Colour or monochrome cameras and monitor?

This is a very common question and a number of factors govern the answer, such as price, what you want from the system and which cameras are most appropriate for your particular environment.

A CCTV system should be designed to suit your needs. The installing company should provide guidance on the suitability of different options, features and benefits – including colour and monochrome units. It may be that you need a camera that will work in colour during the day and automatically switch to monochrome at night!

Recording the CCTV

As it is not usually practical to have a dedicated person to sit and watch a monitor 24 hours a day, the image captured by the camera needs to be recorded so that it can be viewed later, if necessary.

Simple Recording CCTV System


Traditionally, this was done with a time lapse Video Cassette Recorder (VCR) which worked on the same principle as an ordinary domestic video but with the ability to record for a much longer period of time.

However, the VCR has now been superseded by the digital Digital Video Recorder (DVR).  The DVR stores the images on to a disk drive in the same way a home computer stores data. A DVR recording lasts longer than a video tape, it does not wear out and the quality of the image is superior. You can also search for an incident easily by time and date.

Recording off-site ‘to the cloud’

The latest technology enables recording the captured footage off-site, via the internet over ethernet or cellular networks (3G, 4G and soon 5G).  This is saved ‘to the cloud’ – meaning it is stored on computers in data centres – made possible by a visual network adapter (VNA) which also fully encrypts the visual data.

VNAs can, as a fail-over precaution, usually store the video straight onto digital media such as SD cards using the site’s internal computer network – wired/ethernet or WiFi (in case the phoneline or mobile signal are lost).

A cloud-based management system (dashboard style software) allows playback of the video, either in real-time or recorded, using the internet on a computer and mobile device.

A multi camera CCTV system?

Most commercial systems today comprise of more than one camera, but you don’t need a monitor and recorder for each camera; several cameras can share one monitor and hard disc recorder or VNA.

Equipment is available that will split the monitor into displaying four cameras at once, or a four way sequence unit can be used which allows you to choose which camera you would like to view. Alternatively, the automatic mode it will sequence through the four cameras that are connected.

However, the most common way of controlling multiple cameras is via a multiplexer.

To keep it simple, a multiplexer incorporates the above facilities but also has the ability to individually code mark each image from each camera and because of this, a multiplexer allows all of the cameras on a system to be recorded onto one tape or hard drive unit. The multiplexer then uses these code marks to play back the recorded picture from the camera that you wish to view.

Historically multiplexers and recording units were separate pieces of equipment, but recently a number of manufactures have developed units that do both jobs.

What ever you want – What ever you need…


Multi Camera Recording CCTV System

A CCTV system can be designed to fit any scenario you care to imagine, using options from the vast range of equipment available from manufactures worldwide.

Cameras can be internal or external, highly visible or covert. They can be static or fully controllable/movable from a remote location. You can have one camera or hundreds; you can record for one day or 21 days. With a suitable internet connection, you can even view your property when you are abroad.

Get the picture?!!!

Why should I buy a quality CCTV system?

Although CCTV systems can be  purchased from DIY stores, and a capable handyman can install it, it should be remembered that the results from a CCTV system will only ever be as good as the equipment used.

In around 70% of all cases, CCTV footage is found to be inadmissible as evidence in a court of law because the quality of the evidence is considered inadequate. This can be the result of poor design and bad installation and clearly highlights the importance of seeking professional advice from the outset.

A competent specialist company should be able to demonstrate their professionalism and experience in design and installation of CCTV systems.  Most importantly, you must feel confident that the company you choose will listen to and understand your individual CCTV requirements.  Their experience with lens optics and camera technology will guarantee you satisfaction with your system.

A specialist company will also ensure the best value for money by using a different lens or camera mounting positions, for example, which can not only monitor the area at risk but also give an outline view of the surrounding area at the same time.

CCTV system options

CCTV systems can aid the monitoring of stock, personnel, visitors, access control and prevent health and safety incidences.

Systems can range from a simple analogue internal package for smaller premises to highly advanced digital systems integrated with intruder, access control and fire systems.

It is imperative to install the right equipment for specific situations and circumstances if you are to get the most out of the system. That’s where the expertise of our system designers and engineers ensures the technology works for you.

Images can be recorded locally and there is also the facility for them to be monitored remotely by our alarm receiving centre who will alert the police or response agency.

Using the very latest technology and highest quality equipment, we can take CCTV beyond simple basic observation using:

  • Solo or multi camera systems
  • Concealed (covert) cameras
  • Colour or monochrome systems
  • Movement activated systems
  • ADPRO remote camera monitoring systems  installed to BS 8418
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