refers to alternating current electricity. Many CCTV products use 24
volts AC, for which a separate power transformer is required.
AC/DC refers to changing between
alternating current (AC) and direct current (DC). To switch from AC
power to DC a transformer can easily be used to regulate the
current. Power inverters convert DC current to AC current.
Amps (A) are used to measure
electrical current consumption. 1 amp (A) = 1000 milliamps(mA).
Analog indicates a particular
electrical signal which conveys electronic data (i.e. a video signal
or audio signal). Information carried over an analog signal is a
representation of data by continuously varying quantities. An analog
electrical signal has a different value of volts or amperes for
electrical representation of the original excitement (light, sound,
etc.) within a dynamic range specific to the analog device.
Automatic Gain Control
to a circuit within the camera which regulates image brightness
levels for optimum performance and highest video quality.
Automatic Light Control
indicates the image sensor's ability to automatically adjust in
diverse lighting conditions to yield the most vivid video image
is a lens with a
built-in method of automatically controlling the lens aperture for
the best video quality under diverse and changing lighting
conditions. Auto-iris lenses can be especially helpful under very
low light and bright direct forward light.
BNC is the type of connector plug
commonly found on CCTV devices for video and audio input / output
connections. BNC plugs are easily adapted to standard consumer RCA
connectors using a simple one-piece plug adapter. Required for use
with plug and play cable.
Bandwidth indicates the complete
range of frequencies over which a circuit or electronic system can
function with minimal signal loss. In effect, bandwidth indicates
the amount of information and its complexity which can be carried
over a signal. More complex information requires more bandwidth for
an effective signal.
Back Lighting Compensation
indicates the image sensor's ability to automatically adjust in
conditions where lighting is from behind the camera to deliver the
sharpest and highest quality video image possible.
Black & White Camera
referred to as black and white because video image produced is in
shades of gray. Only black and white CCD cameras have the ability to
utilize IR infrared lighting. Even without infrared lighting, a
black & white camera will generally perform better in low light
conditions and deliver a crisp image.
Bullet Camera refers to a camera
with a cylindrical shape using an inline video imaging chip rather
than a board design.
CCD (Charge Coupled Device) is one
of the two main types of image sensors used in digital cameras. When
a picture is taken, the CCD is struck by light coming through the
camera’s lens. Each of the thousands or millions of tiny pixels that
make up the CCD convert this light into electrons. The number of
electrons, usually described as the pixel’s accumulated charge, is
measured, then converted to a digital value. This last step occurs
outside the CCD, in a camera component called an analog-to-digital
CMOS (Complementary Metal-Oxide
Semiconductor) is one of the two main types of image sensors used in
digital cameras. Its basic function is the same as that of a CCD.
CMOS sensors are currently found in only a handful of digital
Coaxial Cable is the most common
types of cable used for transmitting a video signal through copper
wire. This type of wiring has a coaxial cross-section where an outer
shielding protects the actual interior signal conductor from
electromagnetic interference. In the CCTV industry, the term "coax"
usually refers to RG-59 cable with BNC-type plug ends.
Color Cameras produce video images
bearing the entire visible spectrum of colors. The color in pictures
appear vivid, crisp, and distinguished on monitoring and playback of
DC refers to direct current
electricity. Typically 12 volts DC, which can easily be adapted from
standard AC wall outlets using a regulated AC/DC transformer. Unlike
AC current, DC flows in only one direction within a circuit and
therefore requires the correct +/- polarity.
Digital Video Recorder
is capable of accepting one or more video (and sometimes audio)
input signals for recording onto digital storage media. A DVR is
basically a computer specifically designed to gather and compress
video into a digital video format for storage on a hard disk drive
or other form of digital media. Some DVRs offer built-in motion
detection recording and can be viewed remotely and played back over
the internet. Some models may easily be backed up onto external
media, such as built in cd burners.
DVR Card is a device for
installation in a home PC computer which converts that PC into a DVR
digital video recorder by gathering video and compressing it into
digital information onto a computer's hard disk drive.
is a feature
that automatically changes the speed at which light is captured in
fields of video by the CCD image sensor. Automatic electronic
shutter determines the amount of light available and helps deliver
the best quality video by dynamically adjusting for the current
lighting conditions by toning down light levels in very bright
situations and boosting brightness in low lighting situations.
indicates a network
communication device for computer-type devices. Most DVR video
recorders come standard with built-in Ethernet LAN connection (with
'RJ-45' plug) to enable remote internet viewing and/or network
Focal Length indicates the distance
between the optical center of a lens and a video camera's image
sensor device. For practical purposes, Len's focal length refers to
a camera's angle of view. Lenses with a higher focal length number
have more narrow, telephoto fields of view (6-12mm). A very low
number focal length indicates a very wide field of view (2.5-3.6mm).
Fixed Lens has one set focal length
with a specific field of view which cannot be changed. Any camera
without Varifocal option has a fixed focus lens. Meaning, the user
cannot manipulate the field of view, everything in the picture
beyond a few inches will be clear and in focus. Objects simply get
smaller as they move further away from the camera.
Frames per Second
the number of full video frames displayed or recorded within one
second. True Realtime video consists of 30 frames / sec. A complete
frame of video is compiled of two separate images (or fields), so
the number of fields in one second is always twice the number of
frames per second.
FPS Display Rate
number of frames per second a VCR or DVR recorder will display on a
monitor for simultaneous viewing. The rate at which each camera is
displayed is often NOT the same as the number of frames per second
the recorder captures for playback.
FPS Record Rate
how many frames per second a video recorder can actually capture.
Analog recorders like VCRs can easily record in Realtime (30 frames
/ sec. or time-lapse (fewer than 30 frames / sec.).
Hard Disk Drive
(HDD) is a magnetic
media storage device for recording digital information (like that
used by computers or digital DVR video recorders).
HDD Capacity indicates the amount
of information which can be stored on hard disk drive. This figure
is measured in bytes: 1 GB = 1016 MB = 1032256 KB = 1048772000
IR Infra Red Light
is a frequency
of light which is lower than the human eye's visible spectrum (in
the range of 850 ~ 950 nanometers). Color cameras CANNOT use
infrared light whatsoever. However, this special band of light CAN
be detected by most black and white CCD camera. Therefore, a black
and white video camera in combination with infra red lighting can
see in pitch dark conditions. An infra red light source appears just
the same as any visible light source on a black and white camera
JPEG is a standard for compressing
image data. It is not a file format, it’s a compression method that
is used within a file format. Some quality is lost in achieving
JPEG’s high compression rates. Usually, if a high-quality,
low-compression JPEG setting is chosen on a digital camera, the loss
of quality is not detectable to the eye.
LCD (Liquid Crystal Display) is a
low-power monitor often used on the top and/or rear of a digital
camera to display settings or the photo itself.
Lens is an optical device which
bends light, focusing it on onto an image sensor to create a
distinct, visible image. All video cameras need lenses in order to
obtain a clear picture. Lenses come in a variety of focal lengths.
The focal length of a lens, in combination with the size of the
imager, will determine its field of view.
Low Light (or low lux) Sensitivity
refers to a camera's performance under low lighting conditions. Sony
1/3 " Ex-View and SuperHAD CCD chip sets have the best low light
Lux is a measure of light in terms
of candle power (measured in foot candles). Lux is often given as a
technical specification for cameras to describe the lowest level of
light required for the camera to produce any kind of an image.
However, this number lists the absolute lowest level of light needed
to move ANY of the image sensor's pixels. A lower "lux" rating
indicates performance in darker conditions.
Megabyte (MB) is a measurement of
data storage equal to 1024 kilobytes (KB).
Milliamps (mA) is a measure of
electrical current power consumption. 1 amp (A) = 1000 milliamps
Multiplexer is a video switching
device that accepts video input from multiple cameras and converts
them to all display on one monitor and / or video recorder (similar
to a quad video processor) However, a multiplexer is far more
advanced. Video multiplexers use time division multiplexing, meaning
that a full frame of video from each camera is recorded every few
seconds. While multiplexed video does not achieve true Realtime
display or recording (there is a slight drag to the images on
playback), multiplexers do offer the capability to change between a
view of several cameras and a solid close up view of only a single
camera's view on playback of recorded video. When using multiple
cameras, quads and multiplexers help to cut down on the amount of
additional equipment needed for a dedicated surveillance system.
Pan/Tilt/Zoom (PTZ) indicates
equipment with the ability to pan, tilt and zoom, usually controlled
by remote. Much of PTZ equipment is completely integrated, meaning
there is only one controller necessary to operate all three
is a video switching
device that accepts video input from four cameras and converts them
to all display on one monitor and / or video recorder. When using
multiple cameras, quads and multiplexers help to cut down on the
amount of additional equipment needed for a dedicated surveillance
RCA is a common connector plug for
standard consumer video and audio equipment. RCA jacks are found on
all VCRs. In most cases, RCA jacks are color coded yellow, white,
and red. BNC plugs are easily adapted to standard consumer RCA
connectors using a simple one-piece plug adapter.
Remote Playback is a feature of
many DVRs. This allows users to play back recorded video over the
internet from virtually any computer in the world.
is a feature of many
DVRs. This allows users to monitor CCTV cameras over the internet
from virtually any computer in the world.
Resolution (TV lines) refers to the
maximum number of vertical lines /pixel elements (horizontal
resolution) a video camera is capable of displaying on a monitor or
registering with a video recording device. Horizontal resolution
indicates the number of pixel elements placed horizontally across
each scanning line of resolution (vertical resolution). Horizontal
resolution varies based on the abilities of each different camera
and each different monitor. The number of TV lines of horizontal
resolution is generally considered a measure of a camera's level of
detail and sharpness in video quality.
Shutter Speed is a measurement of
how long its shutter remains open as the picture is taken. The
slower the shutter speed, the longer the exposure time. When the
shutter speed is set to 1/125 or simply 125, this means that the
shutter will be open for exactly 1/125th of one second. The shutter
speed and aperture together control the total amount of light
reaching the sensor. Some digital cameras have a shutter priority
mode that allows you to set the shutter speed to your liking.
Time-lapse refers to recording one
still video image frame at fewer than 30 frames per second. The
speed of this recording can usually be adjusted. Time-lapse video is
therefore slower than Realtime recording and has a drag when the
video is played back. One advantage of time-lapse recording is the
ability to increase maximum recording time so longer periods of time
can be captured on a video tape or digital hard disk drive. However,
a major disadvantage of time-lapse recording is missing many frames
of video and missing much of what happens during a given period of
time. There is no way to recover these missed frames on playback.
For the ultimate in surveillance, Realtime video recorders deliver
the most complete and accurate video information of what occurred.
VCR stands for video cassette
recorder. This is an analog device capable of accepting a video (and
usually audio) input signal for recording.
allows the user /
installer to manually adjust the camera's field of view. Varifocal
lenses can therefore be changed to provide wider viewing angles or
narrower telephoto viewing angles. Because of their adjustability,
Varifocal lenses are great when a camera will serve more than one
purpose or to ensure proper focus without first determining an exact
fixed lens focal length. Varifocal lenses are also typically
referred to as zoom lenses.
specifically designed for safe use in most outdoor weather
conditions. However, weatherproof equipment should not be considered
waterproof because it is not intended to be placed in direct
weather. At the same time, there may also be extreme weather
conditions which even standard weatherproof video equipment cannot
function properly. Heating or cooling fans are encouraged for these
types of conditions. Weatherproof cameras must be placed under some
type of eave or covering with or without a housing.
Zero Lux Operation
refers to video
imaging in pitch black (0.0 lux) lighting conditions. Black/White
cameras can use IR lighting to yield crisp and distinguishable video
images when absolutely no visible light is available.
Iris Lenses, Manual
are perfect for common interior surroundings with constant light,
such as interior of shopping centers, schools, libraries, and
offices. Manual Iris Lenses are ideal for such locations, because
the iris setting of the lens only needs to be set once during the
Iris Lenses, Auto
are perfect for
locations, where light is constantly changing, such as outside
parking lot, and building entrances. Auto Iris Lenses are powered
through cameras power supply. The iris for these lenses
automatically opens and closes according to the changes of the light
conditions. If the light level is low, the lens iris opens up to
allow enough light for optimum picture quality, and when the light
level is high, it closes the iris so that incoming light does not
overwhelm the camera and blur out the picture.