FAQ

The most important part of any CCTV system is planning the system, this does not necessarily mean that you have to draw up a detailed plan complete with specifications although this can help with a large system, just know what you want from your system and how you are going to achieve it. Some simple questions to answer will help:

What is the aim of your system?

Today CCTV systems are used in many different ways; monitoring a baby in the nursery; monitoring sick animals in a Veterinary Surgery; monitoring processes in a factory; monitoring traffic flow on major roads; monitoring operations in a warehouse for Health & Safety; etc. But predominately today CCTV systems are used to deter and record crime. So you need to determine what you want from your system. If you are going to require a system that will produce images good enough for evidence in a prosecution you are going to need good quality pictures which Identify an individual clearly.

What areas do you want to cover?

To cover the whole of the premises with a CCTV system is going to be prohibitively expensive so you need to determine which areas you are going to cover and which you are going to "give up". The areas to concentrate on would be areas of high risk, in a shop, for example, this would be where small high value items are on display plus the till counter area with a general view of other areas.

What do you want to see?

The viewing/capture of CCTV pictures are divided into four descriptions; Monitor, Detection, Recognition and Identification. Generally you will need at least one camera that will Identify persons, this is usually at the entrance to the premises, other views can be determined by requirements. For example, if you have a shop you will require a system that Identifies a person entering the shop and allows you to monitor them whilst they are within the shop but would Recognise them within the areas of high risk.

CAMERAS Having planned where you are going to put cameras you need to decide which cameras you are going to require to cover your areas and give the necessary view. Cameras, together with appropriate lenses, will be able to view any area that is required, so the main choices to make is what type of camera you require, the quality of the pictures and the field of view. Most cameras are powered by a 12 volt power source, with PTZ Cameras requiring 24 volts. All modern cameras are digital. Cameras come in many variations, some very basic descriptions to assist you:
· · · · · · · ·	Internal Cameras - made to be used indoors only, it may seem obvious but there is a premium for external cameras (see below) and often internal cameras are used outside in an effort to save money...they don't last long outside. Many of the internal cameras are described as "Dome" cameras which should not be confused with "PTZ Dome Cameras" (see below). External Cameras - made to be used outdoors, weatherproof with sealed cables and tough bodies. IR (Infra-red) - cameras that have the addition of LED's around the lens area which aid viewing in the dark. Box cameras - the classic shaped cameras that are made for internal use only but can also be used inside an "External Housing" to make them weather proof so they can be used externally. Day/Night Cameras - During the day they display in colour and at night they automatically switch to monochrome (black & white). Monochrome gives much better definition in the dark and particularly in infra-red light as colours are very difficult to distinguish in the dark. Vandal or Attack Resistant Cameras - used internally or externally where they are likely to come under attack. Covert Cameras - These are cameras that are hidden inside everyday objects such as alarm PIR's,clocks,smoke detectors etc. they can be used in areas that need to be monitored discretely without obvious knowledge such as stockrooms. PTZ Dome Cameras - Pan, Tilt & Zoom (PTZ) cameras allow for movement of the actual camera, these are used mostly externally in open areas. They are used internally where there is a large space to monitor like a Shopping Centre or large Supermarket. PTZ Domes are expensive to install as they require controlling equipment at the display end.
Resolution of CCTV cameras is measured in TV Lines (TVL) the standard entry level camera will have a resolution of around 330 TVL with High Resolution cameras having 400 TVL or over, but, the higher resolution cameras have a premium. Light (The Friend & Enemy of Cameras) Most CCTV cameras manage the normal environmental ambient light conditions for which they are designed very well, they can adjust to rapid changes in the intensity of the light conditions automatically but they struggle with the very bright (direct) light and the very dark. A camera faced with more brightness than it can handle will shutdown to protect itself and most Day/Night specified cameras will switch to black & white at 0.5 lux. The minimum illumination level of camreas is shown in lux. Light levels are measured in lux. In order to give some understanding to lux. levels please see below: Sunny Day 50,000 - 55,000 lux Cloudy Day 5,000 - 10,000 lux Commercial Internal Lighting 500 lux Stadium or Street Lighting 30 - 50 lux Full Moonlight 0.5 - 0.75 Where the ambient light is insufficient to allow a camera to work normal lighting can be used to supplement the background lighting, remember that "light pollution" can cause problems and in these cases Infra-Red (IR) lighting may be preferable. Day/Night cameras come with integral IR lights. LENSES Most dome & IR cameras come with a lens fitted but this may not give the required view, most lenses can be changed to allow a flexible solution to your needs. Lenses come in two main types "fixed" which means it has a fixed focal length and "vari-focal" which means it has a variable focal length, all lenses can be focused to some degree. Most box cameras do not come with a lens fitted and so a lens must always be added unless it states that a lens is included. Deciding which lens you require can seem complicated, a general rule of thump is that a wide angle lens of 2.8mm will give a wide field of view but not much depth of field a narrow angle lens of 12mm will give a narrow field of view but a deep field of view, so the lower the number the wider the field of view. Beware that very wide lenses (under 2.5mm), sometimes called "fisheye lens" will give distortion around the edges. The most common focal length for lens is 3.6mm.

DIGITAL VIDEO RECORDER Digital Video Recorders (DVR) come in many levels with varied functions from the very basic simplex models to highly sophisticated units. All record to hard disks, as found in a computer, so there is no requirement to change and store tapes. There are many different functions available (listed below) and it is very much deciding which is the most important functions to have and choose an appropriate model. The most important issues to consider when choosing a DVR are:
· · · ·	Channels - one channel is required for each camera in the system, 8 channels will provide enough space for 8 cameras. Consider future requirements with a few spare channels. A typical DVR has 4, 8 or 16 channel. Frame rate - shown as Frames Per Second (FPS) or Images Per Second (IPS). 25 FPS is the equivalent to real time so this needs to be per channel to provide real time on each camera, therefore, to ensure real time a four channel DVR should have a frame rate of 100 FPS. Hard Disk space - there is a considerable choice on the size of Hard Disk available from 160Gb to Terrabytes. Some of the basic DVRs are limited to the amount of Hard Disk space they can have but most DVRs can accept enough space to ensure an acceptable recording time. The actual maximum recording time is very much dependent on the model, the amount of cameras on the system and how it is set up. Some models can have a Hard Disk Array added to extend the amount of space available. Resolution - picture quality is dependent on several factors, some of which can be adjusted on the DVR, but the resolution should be of reasonable quality as a start. A resolution of 352 x 288 pixels is accepted as "good quality" with 704 x 576 pixels being "high resolution. Some DVRs have the ability to record at higher resolution but there is an offset with the high use of Hard Disk space. Evidence Retrieval/Backup - at sometime you will need to provide evidence to the police/authorities or backup incidents to a storage. Most DVRs have an integral CD or DVD writer which allow for easy transfer of incidents, some also have a USB socket which allows for the connection of a pen drive or external hard-drives to backup evidence. Basic models usually have a connection for an external device but no integral device so an external device would be required for evidence retrieval.
There are many different functions available some of which are listed below with brief explanations:
· · · · · · · · · · ·	Networking/Internet Connection - allows monitoring/control over a network or broadband internet connection (requires a static IP address) becoming popular with businesses that have more that one premises. Motion Detection (also called Event Recording) - the DVR can be set to record on the detection of movement which will save disk space. Infra-Red Remote Control - for ease of operation a remote control is provided. Audio Recording - records audio on some channels (will use hard disk space). Alarm inputs - allows for the connection for alarm signals from cameras. Control of PTZ cameras - allows for the control of PTZ cameras without the requirement for additional equipment. Call Monitor - allows for the connection of a second monitor, note this may be limited compared to the main monitor. Digital Zoom - will magnify the picture on the screen digitally. Snapshot - allows a still picture to be captured. Schedule Recordings - allows the DVR to record at specific times only. Recording Speed - allows the change of Frame Rate in order to save Hard Disk space. Covert Camera Setting - allows a channel to be hidden on the display.

IP SOLUTION The main difference between analog camera & IP camera is the way in which the video signal is delivered. Analog cameras turn the video signal into a format that can be received by a television or other receiver such as DVR. An IP-based camera, also known as an IP network camera, digitizes the video signal using a specialized encoder that contains an onboard web server or video server. This allows the IP camera to act as a network device, thus allowing captured video images to be viewed not only through an existing network but also through a web browser that can be accessed through the Internet. Both analog and IP-based video cameras can transmit signals either wirelessly or through wired connections such as Cat-5 cables. IP-based cameras have the added benefit of being able to use switches, hubs, and routers that allow the Cat-5 network to be expanded to much broader ranges. Pros of IP cameras
· · ·	Better wireless reception -- IP cameras have encryption built right into them providing for a more secure network. Interference is also not a problem with IP-based models. Can utilize existing wiring -- Because IP-based cameras act as their own network device, you can take advantage of existing network wiring within your home or office. This can make the installation task much easier. Remote access can be easier -- IP cameras are better suited for remote surveillance needs.
Recorder for analog cameras is Digital Video Recorder (DVR) and for IP cameras or IP servers is Network Video Recorder (NVR). The most recent development is the Hybrid Network Digital Video Recorder (NDVR) which enables both the IP and analog surveillance cameras to work together within one application.

WIRING

Cables are used to connect a camera to a power supply and the DVR, some cameras have the option of audio which will also require a cable.

In order to transmit the picture signal to the DVR a camera is connected to the machine using a type of coax cable called RG59 or RG6 this is similar to, BUT NOT THE SAME AS, coax cable used to connect a television to an aerial. The cable connects to both the camera and the DVR using BNC plugs.

Power is provided to the camera via two core power cable, the connectors used are dependent on the connections provided with the cameras and the terminals at the power supply.

Audio cable, if required, is usually of simple lightweight two core cable but can be a separate RG59 or RG6 cable from the CCTV cable.

RG59 coaxial cable will start to suffer signal loss when it is pulled more than 100 meter, whereas with RG6 signal loss will only occur with cable more than 200meter.

For long distant video transmission Smart Cabling UTP Balun is required. A pair of Balun is required for every deployment of a CCTV camera. CAT5 network cable is used to connect the Balun instead of coaxial cable. One CAT5 network cable (4 twisted pair) can be used for 4 video transmission (4 cameras).

A pair of passive Balun can transmit video signal up to 500 meter. A passive and a active pair of Balun transmits video signal up to 1KM whereas up to 1.5KM for a pair of active Balun.

POWER SUPPLY

Sufficient Ampere is required to supply power to camera. IR camera normally will require more Ampere while the IR LEDs are turned on.

Uninterrupted Power Supply (UPS) is required for both the DVR and the cameras for high risk area deployment. Both the power consumption of the DVR and cameras and the Wattage of the UPS will determine the operating duration of the cctv system during power black out.

Power Surge Protector is a must for deployment at unstable power supply and lightning strikes inclined area. A variety of surge protectors for video, power and data transmission are available.

MONITOR

Monitors can be provided in one of 3 types:

CCTV Monitors, also called "Professional" monitors, these are connected to the DVR via a BNC connector and come in the "standard" metal cased type in sizes of 14 or 21 inch or LCD flat screen type in sizes of 15, 17 or 21 inch. The monitor can on for 24/7.

Television Monitors - televisions can be used as monitors and connect to the system via a scart or AV plug most DVR's allow this type of connection but if this is your choice of monitor check that both the monitor and DVR are compatible.

Standard Monitors - usually used as "computer" monitors these connect to the system via a VGA lead, as a computer connection. Please note that not all DVR's allow for this type of connection so you must check that the DVR has a VGA monitor connector.