What is Closed Circuit
CCTV or Closed Circuit Television refers to a
visible or covert video system intended for only
a limited number of viewers. In Closed Circuit
TV (CCTV) , the picture is viewed or recorded,
but not broadcast. It was initially developed as
a means of security for banks and casinos;
however, today it has been developed to the
point where it is simple and inexpensive enough
to be used with Home Scurity Systems , and for
everyday surveillance .
CCTV is a television transmission system in
which live or prerecorded signals are sent over
a closed loop to a finite and predetermined
group of receivers, usually as scrambled radio
waves that are unscrambled at the point of
reception. CCTV takes numerous forms and
performs a wide range of functions ranging from
image enhancement for the partially sighted to
the transmission of pay-per-view broadcasts.
Although cable television is technically a form
of Closed Circuit TV , the term is generally
used to describe systems with more specialized
applications than a standard broadcast or cable
television. Such specialized systems are not
subject to regulation by the Federal
Communications Commission (FCC); however,
Security Cameras using scrambled radio waves are
in fact subject to common carrier tariffs and
FCC conditions of service.
What is CCTV's primary
CCTV is most commonly used for surveillance.
Security Cameras are now universally featured in
many public and private institutions, from a
correctional facility to the convenience store.
In prisons, reduce the costs of staffing and
operating observation towers and make it
possible to maintain a constant watch on all
areas of the facility. CCTV has become so much
less expensive over the years that both large
and small stores are able to install cameras as
a deterrent against theft and robbery, a
practice, which municipal authorities have
adopted as a way of curtailing crime in public
housing and even on city streets. In many areas
of the country as well as in Europe, Security
Cameras have been placed in highly crowded
public areas as a security measure against
What are some other common
uses of CCTV?
CCTV has many industrial and scientific
applications outside of the world of
surveillance. Electron microscopy, medical
imaging and robotics are all common uses of
CCTV, however, the term "Closed Circuit TV" does
in fact most often refer to security and
surveillance camera systems. Other common forms
of CCTV include live on-site video displays for
special events such as various conventions,
arena sports and concerts as well as
pay-per-view telecasts of sporting events such
as boxing and pro wrestling. Also a common user
of CCTV is "in-house" television channels that
broadcast to very small and specific receivers
such as in hospitals, airports, racetracks,
schools, malls, grocery stores, and municipal
What are the different CCTV
In-Line: These are the most simple model and
thought of as the traditional CCTV . The monitor
or video display is mounted over the camera.
Out-of-Line: These models have a camera unit
and generally use a television as their display.
They are not "portable" in the sense that the
camera unit is a full size camera and the
devices should be used on a desk. The camera
unit would sit beside the monitor, or "out of
CCTV's that use Computer Monitors: These
CCTV's connect simply to a computer monitor.
They are not interchangeable with a television,
but are made specifically for integration with a
monitor. They offer access to the print
material, the computer application, or both
using a split screen function.
Portable : These CCTV's can be considered
portable in that you do not have to use a
television with them. You can purchase a display
that will allow you more freedom in how it is
Hand Held: A Hand Held CCTV is not always
portable. Most models depend on the use of a
television unlike the purely portable CCTV's.
Generally, the ability to write using a hand
held or Portable CCTV is not as functional as
with In-Line or Out-of-Line models.
What are the different
types of CCTV lenses,
There are four
types of lenses for CCTV use : Fixed Aperture,
Manual Iris, Auto Iris, and Zoom. If the area
you wish to observe experiences infrequent
changes in light, use a manual iris lens, which
can be adjusted for light only by hand. If the
area the Security Camera will be observing
experiences frequent changes in light, use an
auto-iris lens. These lenses adjust to light
changes automatically. Auto-iris lenses come in
Video or DC, and cameras generally support one
format or the other. Be sure your lens matches
the camera. To perform close-ups, get a zoom
lens, manual and motorized zoom lenses are
easily available from most retailers.
and how does one
choose which lens to use?