Buying a CCTV system is by no means easy. The vast array of products available nowadays could confuse anyone so we have tried our best to put together a guide to help you make an informed decision about what system should fulfill your requirements.

Before we go through how to choose a complete CCTV System, some people may only want to connect a camera to a TV/Monitor to view and record via a video recorder.

This is simple to do, when you have selected the camera you want pick the option with the correct length 'Plug & Play' cable. Make a note of the 'connector' type, this is usually BNC, then check your TV connections. They will probably be phono or scart. Then you will need to buy a BNC to Phono connector, and if necessary a scart connection. And you're done; you simply plug these connections into the end of your cable, and into your TV. Place the camera where you want and record images on to your video recorder, keeping in mind that it can only record for as long as there is space on the video tape. Of course you will need to "tune" in a channel on your TV to see your camera.

Below we go into more details about the two main parts of a CCTV security system, the Digital Video Recorder (DVR) and the Camera's.

Digital Video Recorder Basics...

The Digital Video Recorder is the "brain" of a CCTV system; it takes the images from the cameras and stores them on to a hard disk drive. You can then look at the images recorded on the hard drive, and review what the cameras have been viewing by connecting a monitor (or other form of display unit) to the DVR. You can forward and rewind through the images in much the same way you may have done so with a typical Video recorder. On many you can search for specific dates and times to quickly find the footage you want to view.

Once you have your images recorded on the hard drive, from time to time there may be an incident which you will be required to give to the police as evidence, you will then need to back up the Data they require from the hard drive on to another storage device.

Backing Up Data...

All Digital Video Recorders store information on a hard drive, something you should consider when choosing your Digital Video Recorder is how you will back-up this Data if there is ever an incident that you may be required to provide evidence of to the police.

Common forms of back-up include:

• Connecting to Video recorder: This is mainly only for 'budget' Digital Video Recorders and involves connecting the Digital Video Recorder to a video recorder and recording the information on to tape.

• USB to PC link: Quite common, and simple to do, simply connect the Digital Video Recorder to a PC via cable and copy information to PC Hard drive, from there you can write on to disk, pen stick etc.

• USB Pen Stick: Quite common and simple to do, amount of storage depends on USB pen stick used.

• CD Rewriter (built in or external): simple to do, some Digital Video Recorders would also require you to load software on to any device that you wanted to then watch the CD on. You should keep this in mind if giving CDs to police as with this software they would not be able to view the CD. Also bare in mind CDs are limited to 750 Megabytes.

• DVD Rewriter (built in or external): simple to do, some Digital Video Recorders would also require you to load software on to any device that you wanted to then watch the DVD on. You should keep this in mind if giving DVDs to police as with this software they would not be able to view the DVD. 4.7Gigabyte of space available.

• Networked: You can copy data from your Digital Video Recorder on to any PC while viewing it over the internet

Digital Video Recorders are available as Standalone units or PC based units. Choosing which one is a personal preference, but I'll take this opportunity to point out a couple of things. Although many PC based Digital Video Recorders offer lots of added features and familiar use, standalone Digital Video Recorders are purpose built for the job and are considered more reliable and therefore less likely to fail. With PC based units we would strongly recommend the pc is used as a security device only and not used as a standard pc with surveillance, this should reduce the risk of failures.

Also if you are "PC savvy" and decide to buy a Digital Video Recorder PC Card and install it into your PC yourself, please check that you will not void your PC warranty before you do.

Last but not least, and this goes for all Digital Video Recorders, where possible try to use a purpose built hard drive. By this we mean that some people, to save costs, use a normal PC hard drive in a Digital Video Recorder. Unfortunately this usually ends up with the hard drive failing simply because a pc hard drive is not designed to be constantly "working" twenty four hours a day - seven days a week. Also please check the compatibility of the hard drive with your Digital Video Recorder, as some may require IDE drives, others SATA, and some may work better with Seagate, others Maxtor.

Ok, now hopefully you have a better idea about what a Digital Video Recorder is, and its purpose, now let's consider the Cameras.

CCTV Camera Basics...

For those who know little or nothing about what a CCTV camera is, or what it does.

CCTV Cameras are the "eyes" of a CCTV system, you place them inside and outside buildings to enable you to see and also record (via a Digital Video Recorder) what the camera is looking at.

Unfortunately that's where it stops being easy, we cant emphasize enough how you need to educate yourself as much as possible about what CCTV cameras are capable of and then look seriously as to what you want to use a camera for and what you need that camera to do. By this we mean there are literally thousands of cameras available nowadays, but this is because there are so many different situations where a camera is required that there isn't just one camera for all jobs.

So how do you go about choosing a camera, well you have to start with basics....

First where is the camera going? Indoors or outdoors? If outdoors use the weatherproof guide to choose what kind of an IP rating your camera requires.

Weather Proof Rating...

Weather proof is measured using an IP Rating, if a camera doesn't state an IP rating you can consider it is for internal use only.

IP Ratings Guide

The IP classification system designates the degree of protection provided by an enclosure against solid objects or water ingress.

There are always two digits in an IP rating, the first digit refers to the protection against solid objects (dust) and the second digit refers to the protection against water.

Dust Protection (first digit):

0 = Non-protected
1 = Protected against a solid object greater than 50mm, such as a hand.
2 = Protected against a solid object greater than 12.5mm, such as a finger.
3 = Protected against a solid object greater than 2.5mm, such as wire or a tool.
4 = Protected against a solid object greater than 1.0mm, such as wire or thin strips.
5 = Dust-protected. Prevents ingress of dust sufficient to cause harm.
6 = Dust tight. No ingress of dust.

Water Protection (second digit):

0 = Non-protected
1 = Protected against dripping water.
2 = Protected against dripping water when tilted up to 15º.
3 = Protected against spraying water at an angle of up to 60º.
4 = Protected against splashing water from any direction.
5 = Protected against jets of water from any direction.
6 = Protected against heavy seas or powerful jets of water. Prevents ingress sufficient to cause harm.
7 = Protected against the effects of temporary immersion in water.
8 = Protected against the effects of continuous immersion in water.

So for using CCTV cameras outdoors, I would recommend a very minimum IP rating of 55, but preferably 65 and above.

Once you know this, go to the area where you want to install the camera and look at what you want the camera to see. How far is the scene you want to capture from the camera? How big is it? Think about this and make sure you know what lens size you need to be able to see the scene you want at the distance it is away. There are many CCTV Lens Calculators on the internet to help you.

Consider, will you need to be able to see in dark conditions? Or only during the day time? If its needs to see in low light conditions, how dark does it get? Is there a street lamp near by? Or is there a security light on the premises? Go back at night time and see how dark it actually is, then use the Lux guide to see what kind of "minimum illumination" your camera requires. Keep in mind during the winter it gets dark very early, no good having a camera that's only useful during the summer.

Lux Guide:

0.00005 lux = Starlight

0.0001 lux = Moonless overcast night sky

0.001 lux = Moonless clear night sky

0.01 lux = Quarter Moon

0.25 lux = Full Moon on a clear night

1 lux = Moonlight at high altitude at tropical latitudes

3 lux = Dark limit of civil twilight under a clear sky

32000 lux = Sunlight on an average day (min.)

100000 lux = Sunlight on an average day (max.)

Is the camera going to be installed in such a place it may be subject to vandalism? If so make sure you use a vandal resistant camera.

Ok, now hopefully you have a better idea about what a CCTV camera is and what kind best suits your situation. With all the above knowledge, I hope it helps you choose a suitable CCTV system for your needs.

And good luck with your security project...

JMC Security is an online distributor of CCTV Camera System systems and products, including CCTV cameras, Digital video recorders and CCTV accessories.