010 596 6666 info@cctvlink.co.za

Your CCTV guide

Tips, tricks, how to guides, glossary and everything you need to know about CCTV

FAQ

These are some of the most frequently asked questions from our customers.

Why buy from CCTVLINK

CCTVLink is a direct importer and distributor of security cameras, surveillance systems, CCTV equipment and accessories for home, business and government. :
Most importantly we provide the best customer service & technical support in the industry. We also strive to provide the most competitive pricing possible
…something else to consider
Our directors have been in the security and CCTV game for 20 years and are experts in their field.
When you buy from us you are assured of support, advice and technical expertise that cannot be matched in the industry

How many cameras do I need?

When setting up a home or office security system, the ideal camera setup, including how many cameras should be used, depends on the characteristics of the area being surveilled, the type of assets being protected, and the type of security camera being used. Generally, having multiple, overlapping security cameras is best in terms of surveillance effectiveness, although this also increases the cost of the overall system.

The most obvious and common place to install security cameras is in entry and egress points. Pretty much everyone who comes into the home or office must pass these points, providing an excellent opportunity to capture them on video.

To capture the faces of those who are missed by the cameras at the entry points, the next best place for cameras is in any traffic choke points.

Read more about Designing an Effective Video Security System here

 

What is your guarantee and returns policy

Our products carry a 12 month warrantee. It is up to the client to send (and pay for the courier costs) us the faulty goods. we will test the products and if faulty, repair or replace it and send the product back to the client within the borders of South Africa. CCTVLINK will pay for the couriers to return the product to the client within the borders of South Africa. If the product was found to be not faulty, the client will pay for the courier costs back to the client.

 

If you are not happy with your purchase made you may return the products within 30 days with its original packaging for a refund. The products must be free of any damage or scratches.

Please note that there is a 10% handling fee which will be deducted from the price. Shipping costs are for your account when returning the products.

How do you send the products

Orders from R1 - R1999 will be shipped by courier at a flat rate of R95. Orders for more than R2000 will be shipped FREE by courier directly to your door.

 

We ship anywhere in South Africa

If you are not in SA please send us an email and we will quote on international shipping

Every item we ship is fully insured, if it gets lost or damaged we will send you a replacement.

Once you have placed your order and paid it takes us 2-4 working days to pack and prepare your order, it is then shipped and the tracking details will be sent to you by email. Courier orders take 2-5 working days once shipped.

What are my payment options?

We make it as easy as possible to shop from us. We offer you a number of ways to pay.

Credit Cards

We accept all major Visa and Mastercard credit cards and debit cards, online through our secure payment gateway.

EFT

You have 2 options with EFT (Electronic Funds Transfer) We can also accept a Direct EFT payment via our payment portal. When choosing this option you will be taken to your secure banking website where you can transact safely and securely. To do this select the PayFast option and then select Instant EFT (read more about this payment option here). Alternatively you can select the EFT payment option when checking out. We will then send you an invoice and you have 24 hours to pay your order before it is cancelled. Please note that we will only ship the order once payment reflects in our account (2 to 3 days)

Other payment options

Through the PayFast gateway you can also pay via Paypal, Ukash, MiMoney or Wallet (Read more about these options here)

COD

We also offer a COD (Cash on Delivery) option: We are in JHB, so this option is only for customers in the JHB area. We will personally deliver the product to your door and you can pay Cash on delivery. This is strictly Cash ( notes ) on delivery, for credit cards please order from the site.

This service costs an extra R300 per order ( not per item )

Deliveries will only take place on weekdays during office hours.

For insurance reasons we do not allow collections.

If you would like to order by COD, please send us an email info@cctvlink.co.za

DIY videos

Go to our YouTube channel for more videos

Some important considerations

Wired vs. Wireless Cameras

Everything is going wireless these days. It is more convenient, cheaper, and easier to install. However, wireless equipment is not as secure as wired equipment. Any wireless signal, whether from a home’s Internet connection or from a security system, can be pirated. For this reason, high-security installations always used hard-wired security cameras. The extra work pays off in greater security.

Digital vs. Analog Cameras

Originally, all security cameras were analog; however, today, many are digital. The video signal is digitized in the camera, and then transmitted to the control/recording center in a digital form. This allows the use of Cat -5/Cat-6 cables (Ethernet cables), which are much less expensive to buy than the coaxial cables needed for analog cameras

Conventional vs. IR Cameras

Night vision infrared cameras (IR) are very fashionable. Many video security packages come with IR cameras. However, some important issues need to be considered when using IR cameras. First, they do not capture the same level of detail as a conventional camera. While facial recognition is possible with IR cameras, it is more difficult, requiring a trained investigator.

The other big problem with IR cameras is that they are limited in range by the IR light source used. Most only have an IR LED mounted on the camera. This can limit the range to as little as 10 meters Additional IR lights can be installed, away from the camera, increasing the range. Always test an IR camera installation to ensure that there is adequate IR lighting in the area where the image needs to be captured

Dome vs Bullet Cameras

Dome Cameras

As the name suggests, these are small CCTV cameras that are mounted inside of a dome, and are typically mounted to ceilings and used in a variety of applications such as corridors, near till points in retail environments, and even in public transport mediums like buses and trains.

Bullet Cameras

Bullet cameras usually mount to the side of a wall and look like the barrel of a shotgun or a bullet casing.

Click to view our handy flowchart

DomeVSBullet

Fixed vs. Panning Cameras

Many people like panning cameras, more for the fact that they are providing a changing scene, rather than a constant, still image. However, any criminal can time the pan of the camera and find a "window" to slip through. For this reason, panning cameras should only be used in conjunction with other fixed cameras. In such a case, the criminal may pay so much attention to the panning camera that they ignore the fixed one.

Panning cameras are the most useful for keeping a general eye on a large area, looking for potential problems. However, for gathering evidence of a crime, fixed cameras are better.

Types of video recorders

DVRs

Short for “digital video recorders”, these devices are used for storing footage received by one or more cameras. They are called digital recorders because they use computer hard drives to store film footage rather than cassette tapes like the ones commonly used for many decades.

NVRs

Unlike a DVR, a NVR is not limited to the same area as your cameras cabling to one section. The unit can be placed virtually anywhere, it simply just needs to be on the same LAN network as the IP based cameras.

 

NVR vs DVR – The difference between an NVR and DVR can be confusing to many. A network video recorder (NVR) records IP cameras that are transmitted via a network cable. These cameras connect to an NVR either by way of a network switch or router and in some cases directly to the recorder itself. In essence, NVRs record IP cameras. Digital video recorders (DVRs) are synonymous with recording analog or coax based cameras. Newer HD-SDI or HD-CVI cameras also transmit via coax cable and also use DVRs to record. So in short, a DVR records cameras that are connected via a coax cable. There are more technical details involved explaining the two technologies but for the purpose of this article we will keep it as simple as possible. They both record cameras and offer the same similar options but they record different transmission methods.

Lenses

Proper lens selection is probably the most critical aspect of camera selection. The first issue is whether to use a lens with a manual iris or one with an automatic iris. The iris controls the amount of light entering the camera. In cases where this is a constant, such as in the reception area of an office, a manual iris is best. Then it can be set for maximum visibility and left that way. In cases where the camera is subject to changes in light level, such as outdoors, an automatic iris is best. The other major issue involving lenses is the focal length. This determines the camera’s viewing angle. As previously mentioned, it is important not to waste the camera by taking pictures of empty walls. Proper lens selection provides the ability to surveil the necessary area and no more.

 

Focal Length Viewing Angle Width Viewing Angle Height Field of View at 10 feet Field of View at 25 feet Field of View at 50 feet
3.6 mm 74° 55° 15 ft. 38 ft. 75 ft.
4.0 mm 69° 49° 12 ft. 30 ft. 30 ft.
4.3 mm 65° 45° 11 ft. 28 ft. 58 ft.
6 mm 42° 32° 8 ft. 19 ft. 38 ft.
8 mm 32° 24° 6 ft. 14 ft. 29 ft.
12 mm 22° 17° 4 ft. 10 ft. 19 ft.
16 mm 19° 15° 3 ft. 7 ft. 14 ft.
60 mm 5° 3° 1 ft. 2 ft. 4 ft.

The field of view mentioned in the above chart is only the width. As security cameras still use a 4:3 aspect ratio, which means that the image height will be 75 percent of the width. To determine if a specific camera and lens arrangement will work to surveil a particular area, it is best to lay out the camera’s location and the viewing angle on a floor plan of the building, showing exactly how wide an angle will be covered. This should be done for both the width and the height.

Hard Disk Drives

Desktop drives vs. surveillance-class storage

You wouldn’t use a bicycle to transport cargo across the country because it’s not the right tool for the job. You also shouldn’t use a desktop hard drive in your surveillance security system because it wasn’t designed for that application.

WD Purple surveillance-class storage has been tested to be compatible in a wide-range of security systems. These drives are designed to replace standard desktop drives that were not designed for the harsh 24/7 always-on, high-definition surveillance environment. Desktop drives are built to run for only short intervals and are not engineered to withstand high-temperature fluctuations and equipment vibrations found in a typical surveillance application.

Glossary of terms

A B C D E F G H I J K L M N O P Q R S T U V W

A

ADC. The Analogue to Digital Converter in a CCTV application is the device that converts the composite video signal (which is a wave form of 1volt peak to peak) into a digital form. In simple terms the ADC does this conversion by sampling the voltage of the composite video wave at a set frequency (sampling rate) and assigns a binary value (digital bits) to equal that voltage value. This is then transmitted in digital form as a series of "1"s and "0"s.

AGC. Automatic Gain Control controls the video amplitude as the light conditions change. If this is manually set too high, it can cause noisy interference to appear in the picture during low light conditions.

Aperture. Aperture is the part of the camera's lens that allows the light to pass through. The lens iris controls the size of the aperture.

Auto Iris (AI). Auto Iris lenses adjust for the changing light conditions within the field of view, for example, as the sun moves through the day, if it shines directly into the lens, the sensor will adjust the iris so that the picture remains clear.

AWB. Automatic White Balance controls the automatic adjustments made of the light sensor's colour temperature, in order to maintain the best image by keeping white objects white and so on.

Angle of View – It is the angular extent of a given area that is covered by a picture. If you wish to cover a wider area through your security system, then such a camera and lens combination should be selected which has a higher Angel of View. Attenuation – It means the loss or reduction in an electrical signal, occurring due to absorption, scattering or interference. Aspect Ratio – It is the ratio between the height of the picture frame and its width.

B

BALUN. Balance / Unbalance. In a video application, a balun can be used to transmit video signals along unshielded twisted pair (UTP) cable such as Cat5e instead of using coaxial cables. The composite video output from a camera is unbalanced at 75Ω impedance. This is converted to video along UTP cable which is balanced at 100Ω impedance and then at the DVR converted back to unbalanced 75Ω impedance.Passive baluns have an effective range of between 200 to 300 metres. Active (powered) baluns have an effective range of between 1500 to 2000 metres. A passive balun combined with an active receiver  can achieve an effective range of 1000 metres.

Bit. In digital networking a Bit is the smallest unit of data transfer. Bits represent the two binary values "on" or "off" and are transmitted and stored as the digital number "1" and "0".

Byte. Is a sequence of bits; usually eight bits is equal to one byte.

Baud Rate. is a number setting that defines the number of symbols of data to be made in a transmission signal / per second. It is used to set the symbol rate for the communication between a Pan Tilt Zoom camera and a keypad controller or DVR, so that they can effectively talk to each other. The lower the Baud Rate selected means the further the transmission distance without errors.

BLC. Back Light Compensation allows the camera to automatically adjust the exposure of the entire image in order to properly expose the subject in the foreground when a bright light source is situated behind it (for example, subject inside an open doorway during a bright sunny day).

Buffer – Buffer is the material that surrounds the fibre to shield it against physical damage or harm.

C

CCD. Charged Couple Device - a light sensitive imaging device that captures the light levels of the picture and translates it into electrons for the camera to "paint" each frame. CCDs come in various surface sizes, typically for CCTV these are 1/2", 1/3" and 1/4".

CMOS. Complementary Metal-Oxide Semiconductor is a light sensitive imaging sensor. Generally cheaper to produce than a CCD, they are not considered to be as good as a CCD; however the technology is improving with time and issues such as blooming and rolling shutter are getting better.

C Mount. An older standard for the screw on CCTV camera lens and designed to fit older C Mount cameras. TC Mount lenses and cameras are matched so that the distance of the mount surface and focusing plane provide a clear image. Newer CS Mount cameras can use C Mount lenses, however a 5mm collar is required between the lens and camera in order to maintain the correct lens to focusing plane distance.

CODEC. Compression / Decompression techniques are used in digital CCTV in order to reduce the size of the image files for recording and transmission purposes. Typical compression format standards used in CCTV video are MJPEG, MPEG-4 and H.264.

CS Mount. The current standard for the screw on CCTV camera lens, designed to fit newer CS Mount cameras. CS Mount lenses and cameras are matched so that the distance from the back of the lens to the camera focusing plane provides a clear image. CS Mount lens can be fitted to older C Mount cameras by using a 5mm collar, however older C Mount lenses cannot be used by newer CS Mount cameras.

CIF. Common Intermediate Format, is a format used to standardise the horizontal and vertical resolutions in pixels of video converted to a digital form.The typical PAL standards are:CIF (PAL) = 352 x 288 pixels (about one quarter of the maximum D1 resolution). Used typically as a recording resolution standard by the mid level DVRs and a video resolution standard for remote streaming by high level DVRs. CIF is also the resolution standard for a Video CD.QCIF (PAL) = 176 x 144 pixels [Quarter CIF] (one quarter size of CIF). Used typically as a video resolution standard for remote streaming via a mobile phone.4CIF (PAL) = 704 x 576 pixel [4 x CIF and nearly D1 (Digital Video) quality] Used typically as a higher end standard for video conferencing_ _ _ _ _ _The typical NTSC standards are: CIF (NTSC) = 352 x 240 pixelsQCIF (NTSC) = 176 x 144 pixels4CIF (NTSC) = 704 x 480 pixels

Crosstalk – It is an unsolicited signal which affects the video signal.

D

D1 (PAL). A digital resolution standard for composite (analogue) video systems following the analogue to digital conversion at the camera or DVR. PAL analogue video consists of 625 scan lines total of which 576 lines are video; this resolution standard is sometimes written as D1 (625). D1 is the highest digital image standard that PAL in a 4:3 aspect is converted to; equal to 720 pixels across and 576 pixels down (or 0.41 megapixel).

D1 (NTSC). A digital resolution standard for composite (analogue) video systems following the analogue to digital conversion at the camera or DVR. NTSC analogue video consists of 525 scan lines total of which 480 [sic 483] lines are video; this resolution standard is sometimes written as D1 (525). D1 is the highest digital image standard that NTSC in a 4:3 aspect is converted to; equal to 704 pixels across and 480 pixels down (or 0.33 megapixel).

Day / Night.  A camera that is define as Day / Night means it is able to capture video in both day time and night time. Cameras achieve this in different ways. The best standard is a "True Day / Night" camera. It has a filter that blocks infrared light reaching the imager during the day, and removes that filter at night in order to enhance the imager sensitivity to IR illumination. Also the camera chip set switches off the colour filters of the image device and therefore senses only light and dark tones (black and white). Micro-possessors stabilise and enhance the night time images. A digital Day / Night camera does not have an IR filter. It also switches off the colour filters of the image device at night and better models use micro-possessing to stabilise the image.

dB. deciBel. The standard unit of measurement for the Signal to Noise Ratio. Higher values represent clearer images, ideally between 48dB to 52dB.

DNR. Digital Noise Reduction is the process of removing noise that appears in the video image by passing it through digital filters. Noise can be created in low light conditions, as the camera tries to compensate for the lower volume of light hitting the sensor, and can occur during camera movement (in a PTZ system) where blurring effects can be produced.

DSP. Digital Signal Processing - a technique used to adjust the video signal parameters in order to improve it. It is part of the Analogue to Digital Converter process.

Dual Voltage. Cameras that have a dual voltage option, generally accept either a 24V AC or a 12V DC power source. Voltage is the "pressure" that pushes the Amps along the cable. A 24V AC system is better where the power line is longer because there will be less voltage drop between the power supply and the camera cause by the resistance in the cable.

DVR. Digital Video Recorder - is a device that has a number of analogue camera (point to point) inputs (usually 4 channels, 8 channels, 16 channel or 32 channels). The DVR converts each analogue video input into a digital form and stores the digital video onto a digital media storage device, typically a Hard Disc Drive. Some DVR's also provide internet connectivity for remote access and alarm emails. DVRs are now standard in CCTV recording, replacing the old Video Cassette Recorder.

Desktop Switcher – A Desktop Switcher is an instrument used to switch the video signal from various cameras to one or more screens. Dwell Time – It is the time duration for which a switcher holds a camera before switching to the next camera in the arrangement.

F

FPS (Frames Per Second). The Broadcast Standard is 25 FPS in a PAL video system and 30 FPS in a NTSC video system. In a CCTV application, the recorded rate of FPS can be adjusted down as one method to reduce the amount of disc space required to store the video and the transmission bandwidth required to send the video data over a network. A very low rate of FPS will have a negative impact on the effectiveness of any recorded CCTV video during playback of an event of interest.

F Stop. Is the value of the aperture opening, that describes the amount of light that will pass through the lens. Lower number means better images.

Field of View – In simple terms, Field of View is what a person will be able to see via the camera. Frame – It is a comprehensive image made up of horizontal and vertical lines.

G

Gamma correction. This refers to the automatic correction installed into a camera that adjusts for the brightness characteristics of the monitor.

Gen-Lock. The use of the sync pulse characteristics of the composite video (vertical or horizontal sync) in order to synchronise one or more cameras within a system is known as Gen-Lock.

Ghost or Ghosting. Is an image moving across the screen that leaves a brief shadow of itself, like a smear or blur. It can occur in low quality monitors. Technically a secondary video signal is displayed because it has been received either earlier or later than the primary video signal.

Ground Loop (interference). This type of picture interference occurs when the ends of the composite video cable have difference ground potentials, causing an AC current to appear in the grounding in the system. The effects in the video are annoying distortions of horizontal light and/or dark bars across the width of the screen, that usually roll up the screen from bottom to top. The installation of Ground Loop isolators can eliminate the problem.

GUI (Graphical User Interface). Pronounced "gooey" this is an interface between the computer and the matrix switcher. Active areas of the screen are programmable, with feature menus, icon are clickable and are able to activate devices such as DVRs. A GUI makes the CCTV system easier to use, and can be found in alarm receiving stations and CCTV monitoring rooms.

H

H.264 or MPEG-4 Part 10, Advanced Video Coding is a video compression format that is currently one of the most commonly used formats for the recording, compression and distribution of video content.

Hertz (Hz). A hertz is the unit of measurement frequency, with 1 Hz equal to one cycle per second. PAL composite video signals are 8MHz (8,000,000 Hz) overall; with PAL-D using 6MHz for the video part of the signal.

Hum Bars. Horizontal Hum Bars that are either black and/or white appear across the video as interference. They fill the picture from top to bottom and represent an annoying 'venetian blind' type artefact over the picture. The line can also be rolling up or down the screen. Hum is caused by the 50 Hz electrical interference frequency of an AC circuit, motor or power source. It can be eliminated by placing isolators or chokes in line with the video cable.

I

IP (Internet Protocol). Generally this term in a CCTV application refers to cameras that conduct the analogue to digital conversion at source and then transmits the digital video data using internet protocols across an network infrastructure to a video server or network recorder.

IR (Infrared). Infrared light exists in nature however it is just outside the visible spectrum of radiant light that we can see. Some camera image sensors however are sensitive to infrared light. This is extremely useful when we want to illuminate a night scene but do not want to flooding the area with visible light. It is also important to consider that cameras "see" the IR light that is reflected back towards the lens.

IR LEDs. Infrared Light Emitting Diodes is a relatively cheap way to produce IR light in a CCTV application. These small diodes are easily integrated into day / night camera's construction.Generally there are two common types of IR LED illuminators.IR LEDs at 940nm (nanometers) on the light spectrum wavelength are completely invisible to the human eyes and are suitable for covert / tactical CCTV installations. They are however more expensive to produce and buy.IR LEDs at 850nm on the light spectrum wavelength are much more common. These are just on the fringe of IR (near-infrared) and at night you can see a red / purple glow off them.

Ident – All the characters that are created on a video signal are included in the Ident, such as titles, time and date, etc. Incident Light – This is the amount of light which is on an object.

L

Lux – Lux is a unit of measure which determines the intensity of a light source.

M

Monochrome – A Monochrome is a black and white image. Monochromes are usually suggested for use with cameras that are placed outside your workplace or home, simply because they have superior picture resolution during night-time. Monitor – It is a device which displays video signals to be watched by the user of the security system.

N

NTSC. National Television System Committee, is a colour encoding system for analogue television. It consists of 525 scan lines of which 483 lines are video, with the other lines used for synchronisation and retrace. NTSC video typically consists of 60 interlaced fields per second [60 Hertz] equal to 30 frames per second. NTSC video is used in those countries where the utility (electricity) supply is also at 60 Hertz, mainly, North America, Central America and part of South America, South Korea, Taiwan, Japan and the Philippines.

NVR. Network Video Recorder, is a device attached to a network through which IP (network) cameras are transmitting their digital video. The NVR will be the receiving this video data and storing it onto digital media, such as a computer hard disc drive. The NVR will be the device that also provides for remote access to live video, playback, alarms triggers and events, such as sending email alerts.

O

OLPF. Optical Low Pass Filters remove the Moire effect created by checked patterns or lines close together in the image

 

P

PAL. Phase Alternating Line, is a colour encoding system for analogue television. It consists of 625 scan lines of which 576 lines are video, with the other lines used for synchronisation and retrace. PAL video typically consists of 50 interlaced fields per second [50 Hertz] equal to 25 frames per second. PAL video is used in those countries where the utility (electricity) supply is also at 50 Hertz, mainly, Europe, Asia, Australia and part of South America.

PTZ. Pan Tilt Zoom. A camera that has the ability to move left and right (Pan) and up and down (Tilt) and focus near and far (Zoom). The pan tilt function is provided by a two axis motorized gimbal. The zoom function is provided by a motorized lens.

Pinhole Lens – This type of lens is generally used with hidden cameras.

Q

Quad – A Quad is a device which shows up to four cameras on the screen of the monitor at the same time.

R

RS232. Is a standard for serial communication transmission data, commonly through computer serial ports. It is an older technology, that is used to control peripheral devices, (such as a PTZ camera) from a computer or keyboard. RS232 has virtually been replaced by USBs.

RS485. Is a standard for serial communication transmission data using a pair of wires, to control peripheral devices. It is still commonly used due to its simple application of using bi-wire (such as twisted pair / Cat5).

Roll – It is the loss of vertical synchronization which often results in the image being distorted and causes it to move up or down on the monitor.

S

SIF. Source Input Format, defined in MPEG-1, is a video format that was developed for the storage and transmission of digital video.For PAL (625 scan lines at 50 fields per second) the resolution is 352 x 288 active pixels and a refresh rate of 25 frames per second. For NTSC (525 scan lines at 60 fields per second) the resolution is 352 x 240 active pixels and a refresh rate of 29.97 frames per second.When compared to the CCIR 601 specifications defining the values for digital encoding of composite (analogue) video, SIF can be seen as reduced bu half in all height, width, frame-rate and chrominance.The computer industry standards define square pixel SIF to be 320 x 240 (QVGA) 384 x 288 active pixels with a refresh rate of whatever the computer is capable of supporting.

Screen Splitter – It is a device which displays the views from two different cameras on a single screen simultaneously. The split can be set horizontally, vertically or in such a manner wherein one image is placed into another.

T

TVL. Television Lines of Resolution. Typically the term refers to the horizontal resolution of a composite video signal, defining the number of lines that can be clearly resolved across the picture width that is equal to the picture height (TVL PH)

Time-Lapse Recorder – This is a video recording device which reduces the speed at which images are recorded.  

V

VMD. Video Motion Detection is a setting in a camera or digital recorder that "detects" a change from one frame to the next and determines that the change of the whole image (or part of the image being monitored) is due to some form of motion in front of the camera. This technology has a limited application, especially outside, where natural movements and weather conditions can cause "False Positives" to occur.

W

WDR. Wide Dynamic Range is a process whereby the camera digitally adjusts the exposure in areas of the picture frame in order to maintain the optimum levels of exposure across bright and dark areas under observation.