CCTV Term |
Definition |
AC adaptor |
Also called a power supply. All CCTV
devices needs power of some sort. Each device has its own power
requirements (usually 12 volts with a minimum amperage). The power coming
out of the wall (in the US) is 110 to 120 AC. The adaptor converts the AC
power to DC power and will adjust it to a specified amperage. The power
supply should be included with each item - you usually don't have to buy
these separately. |
alarm input |
An input connection to a security VCR or
DVR that triggers the unit to start recording if the alarm is triggered. |
analog |
There are two main ways of doing things
electronically, analog or digital. An analog signal can be represented as
a series of sine waves. The term originated because the modulation of the
carrier wave is analogous to the fluctuations of the human voice or other
sound that is being transmitted. |
analog system |
Most cameras used in cctv
applications are analog. Security VCRs, switchers, multiplexors and quads
also are analog devices. Any cctv system that consists of analog devices
are considered analog systems. Compare to 'digital systems'. |
angle of view |
For security cameras, this refers to the
angular range in degrees that you can focus the camera on without
distorting the image. When focusing close up, you can generally see a wide
angle of view. If the focus is distant, the angle of view is smaller or
narrower. |
aperture |
The opening of a lens which controls the
amount of light let into the camera. The size of the aperture is
controlled by the iris adjustment. By increasing the f stop number (f1.4,
f1.8, f2.8, etc.) less light is permitted to pass into the camera. |
armor dome camera |
These cameras are designed to resist
vandalism by using a hi-impact reinforced polycarbonate dome casing. |
audio |
Most cameras capture 'video' only (what
you can see) - some come with audio too (sound). You can add a microphone
to a security system to capture audio if needed. To record the sound, your
recording device needs to support audio (must have at least one audio
input). |
auto electronic shutter |
The ability of the camera to compensate
for moderate light changes in indoor applications without the use of auto
iris lenses. |
auto iris control |
A lens in which the aperture automatically
opens or closes to maintain proper light levels on the faceplate of the
camera pickup device. |
auto gain control |
An electronic circuit used by which the
gain of a signal is automatically adjusted as a function of its input or
other specified parameter. |
auto white balance |
A feature on color cameras that constantly
monitors the light and adjusts its color to maintain white areas. |
back light compensation |
A feature on newer CCD cameras which
electronically compensates for high background lighting to give detail
which would normally be silhouetted. |
bullet camera |
A type of camera with a bullet like shape.
Can be used inside or out. Some come with infrared lighting. |
c-mount camera |
C-Mount cameras are designed to accomodate
custom lenses. The lenses can be removed and replaced. |
cable |
The wiring used to connect electronic
devices. Cables tranmit different kinds of signals such as video, power,
data, and audio signals. Refer to plug and play cable and RG59 siamese
cable for more information. |
ccd |
Stands for "charge-coupled device". First
invented in the 1970s, this technology uses a shift register combined with
photodiodes to create the modern day imaging device. Used in cameras,
scanners, fax machines, etc. The size of the CCD chip is normally 1/4",
1/3" or 1/2". As a rule of thumb, the larger the size, the higher the
quality of the image produced and the higher the price. However some of
the higher density 1/4" and 1/3" CCD chips can now produce as good an
image as many of the 1/3" or 1/2" chips. |
cctv |
Closed-circuit television. |
compression |
Refers to taking an incoming signal or
image, which can be analog or digital, and compressing the data so it can
be stored or transmitted faster and using less resources. There are many
different algorithms and techniques that are used to compress data. |
covert |
A covert application refers to a situation
where you don't want the person to know that they are being watched or
recorded. Also known as 'hidden' cameras. |
day / night camera |
"Day/Night Cameras" are regular cameras
with an especially sensitive CCD chip that allows a good image to be
captured in very low ambient lighting (regular lighting - not infrared).
Do not confuse these cameras with "Night Vision" cameras which is another
name for infrared cameras. |
digital |
There are two main ways of doing things
electronically, analog or digital. The digital method is to consider a
circuit either on or off. A digital voltage or signal refers to the
discrete nature of digital voltage potentials in digital circuits. TTL
(Bipolar Transistor-Transistor Logic) defines 0.0 Volts as a logic 0 or
low, and 5.0 Volts as a logic 1 or high; These are single values for
clarity - there are actually ranges of voltage potentials around 0.0V and
5.0V which are recognized as low and high logic levels, respectively. |
digital system |
CCTV systems are just lately coming into
the digital age. Most security cameras are still analog. There are some
digital cameras available but they are extremely expensive. Where digital
technology is really making ground in CCTV is with digital video recorders
(or DVRs). Any CCTV system that includes a DVR is considered a digital
system. |
digital video recorder (dvr) |
A digital video recorder is basically a
computer that converts the incoming (analog) signal from the cameras to
digital, and compresses it, and stores it. The DVR replaces the function
of a multiplexor (or quad or switcher) and a security VCR. There are many
advantages of digital video recorders over their analog counterparts. |
dome camera |
A type of camera with a dome like shape.
Usually used inside only. Some come with infrared lighting and some are
designed to be tamper-proof. |
duplex |
A duplex device can transmit data into and
out of the electronic device at the same time. For example, a full duplex
digital video recorder can continue capturing and recording images even
while a different image is being displayed. |
frames per second (fps) |
In digital video applications, refers to
the number of video images that can be captured, displayed, or recorded in
a second. Also referred to as the 'frame rate' or 'refresh rate'. |
housing |
Special covering or container to protect a
camera from extreme temperatures or weather conditions. |
infrared |
The region of the electromagnetic spectrum
bounded by the long-wavelength extreme of the visible spectrum
(approximately 0.7 m) and the shortest microwaves (approximately 0.1 mm). |
infrared camera |
Infrared cameras (aka night vision
cameras) have special infrared lights installed around the perimeter of
the camera lens. This provides special light that the camera uses to
capture a good picture even in total darkness. |
iris |
The iris (on some lenses) controls how
much light is let into the camera lens. |
jpeg (or jpg) |
Pronounced "jay-peg" and stands for "Joint
Photographic Experts Group" who designed the standard. This is a standard
way of compressing images which works particularily well for photographic
images (as opposed to graphic art). |
lens |
The lens of the camera determines the
angle of view and the focus of the captured image. There are many
different lens options. |
low light |
Refers to very dim lighting, even 'normal'
darkness. Complete darkness is 0 lux. Infrared cameras
work well in very low light conditions. |
lux |
Refers to the amount of light required for
a camera to capture a good image. Infrared cameras have very low lux. |
micro camera |
Very small cameras designed to work in
covert applications where you don't want people to know that the camera is
there. Also called 'hidden cameras'. |
monitor |
Security monitors are used to display the
images from your cameras (or captured on your recording device). There are
two basic kinds used today in CCTV applications. Analog or composite video
monitors are used to display images in analog systems. They are just like
a TV screen without the TV receiver. These are the monitors we have for
sale on our site. Digital or VGA monitors (just like on your computer) are
used with digital devices like the Digital Video Recorders. We don't
include the monitor with our digital video recorders because you can pick
one up more affordably at your local computer store (and not have to pay
the shipping cost for such a heavy item). |
motion detection |
Refers to the feature in some VCRs and
DVRs to only record video if something in the image moves or changes.
Therefore you don't have to look through hours of taped video looking for
something to happen. It also saves a lot of space on the tape or hard
drive. |
mounting bracket |
Various different kinds of mounting
brackets are used to install cameras to the wall or ceiling. |
mpeg (or mpg) |
Pronounced "em-peg" and stands for "Motion
Picture Experts Group" who designed the standard. This is a standard way
of compressing audio and video files. (It's also the technology behind the
now world-famous MP3 music files.) |
multiplexor |
A device that can accept a number of
camera inputs and almost simultaneously display them on a single monitor
and/or record them. Multixplexers can also be used to transmit multiple
cameras over the same transmission medium. |
outdoor camera |
Outdoor cameras come in special
weatherproof housings that allow them to stand up well in tough weather
and temperature conditions. |
pan-tilt-zoom (PTZ) cameras |
PTZ cameras allow you to adjust the
position ('pan' is side-to-side, 'tilt' is up-and-down) and focus ('zoom')
of the camera using a remote controller. Due to this added functionality,
these cameras tend to cost much more than non-PTZ cameras |
pin-hole camera |
Pin-hole cameras have a very small lens
that can see through a small hole. These types of cameras are used in
covert applications. A disadvantage of pin-hole cameras is that they
require more lighting than normal cameras to capture a good clear picture. |
plug and play cable |
A cable that makes wiring cameras easy.
Each camera needs to have a power wire and video wire (and sometimes an
audio wire too), plus the connectors at the end of the wire to plug it in.
The plug and play cables have all three wires built into one cable with
the connectors already attached. The only disadvantage of plug and play
cable is that the signal tends to degrade if run distances. For DVRs -
plug and play cables can be run reliably up to 100 ft. For analog systems
- plug and play cable can be run up to 400 ft. If you need to run longer
distances then you need to use the RG59 siamese cable. |
power supply |
Also called an AC adaptor. All cctv
devices needs power of some sort. Each device has its own power
requirements (usually 12 volts with a minimum amperage). The power coming
out of the wall (in the US) is 110 to 120 AC. The power supply converts
the AC power to DC power and will adjust it to a specified amperage. The
power supply should be included with each item - you don't have to buy
these separately. |
quad |
An analog device used to display 4 cameras
simultaneously on a single monitor. |
RG59 siamese cable |
This type of cable combines the power wire
with the video wire. You have to add your own connectors to each end of
the cable. Use this type of cable when you need to run distances longer
than 100 ft with a digital system, or more than 400 ft. with an analog
system (see the plug and play cable above). The RG59 siamese cable can be
run reliably up to 1000 ft. |
real-time recording |
In digital video applications, 30 frames
per second per camera (see above) looks just like real-time. There is no
hesitation or jerkiness in the video. |
remote surveillance |
The ability to view your cameras from a
remote location. Information is transmitted via phone line or internet. |
resolution |
Refers to how much detail can be captured
on a camera or displayed on a monitor. Cameras typically capture about 380
horizontal lines of resolution. High resolution cameras may capture 450
lines of resolution or more. The higher the resolution, the more detail
that can be captured in a picture. The monitors and recording devices can
generally handle at least as much resolution as the cameras can capture. |
Smart Search |
This is a feature of our digital video
recorders that allows you to search for changes in a particular area of an
image over time. For example, if a wallet was stolen off of a table, you
could go to a point on the video where the wallet is there, draw a virtual
box around that area, then search the video recording for changes to that
particular area. This would allow you to locate the exact point on the
video where the wallet was removed. |
s/n ration |
signal to noise ratio; this number
represents how much signal noise the camera can tolerate and still provide
a good picture. The higher the number the better. |
switch |
A switch will take multiple camera inputs
and will show them on the monitor one at a time. Unlike a quad it will not
display them all at once, instead it sequences through them showing one
camera at a time. It will also allow you to select a particular camera to
view. |
time-lapse VCR |
A VCR that can be set to slow down its
recording rate in order to extend the length of time that can be recorded
on a standard tape up to as much as 960 hours. This is possible by
recording one frame at time at set time intervals. Most units have an
alarm input signal so it can be automatically switched to real time mode
in case of an alarm. |
transformer |
A device used to transfer electric energy
from one circuit to another, especially a pair of multiply wound,
inductively coupled wire coils that effect such a transfer with a change
in voltage, current, phase, or other electric characteristic. |
varifocal lens |
A camera lens in which the focus is not
fixed, it can be manually or automatically adjusted. |
VCR |
Videocassette recorder; an electronic
device for recording and playing back video images and sound on a
videocassette. |
video capture card |
Computer cards that you can install on the
motherboard of your own computer to create your own video recording
computer. Due to compatibility issues with this type of device, we do not
sell these separately. |
video gain |
An increase in video signal power by an
amplifier, expressed as the ratio of output to input. Also called
amplification. |
video input |
A connection in a video controller or
recording device that you can plug a camera into. The more video inputs
(also called camera inputs) available on a device the more cameras you can
connect to it. |
watch dog timer circuit protection |
If problems are detected in the DVR
computer the system will automatically reboot to correct the problem. |
waterproof |
A device that can be immersed in water and
still function properly. |
weatherproof |
A device that is weatherproof can be
installed outside and stand up to harsh weather conditions and
temperatures. However, it does not mean that it is waterproof. |
wireless camera |
Wireless cameras allow the transmission of
video and audio data to be transmitted to the receiver without having to
run wires (using radiowaves). |