 The system consists of a camera unit which is installed
overlooking the place to be monitored and an indoor video monitor unit that incorporates
an intercom also. When the door bell rings the video unit becomes active enabling the
image of the visitor to be seen at the monitor inside. One can also communicate with the
visitor through the intercom. The electrically operated door locking system can be used to
open the door remotely. The electric locks come with a battery backup protection also,
just in case there is a power failure. Otherwise these locks can be manually operated
also.
 While using
the video door phone one has to keep in mind that there is a limited area that can be
viewed by the camera. In the Video door-phone, normally the camera is located within the
speaker unit for the visitor. This means that camera is at the height of the visitor. Now
if someone accompanying the visitor does not stand close to the visitor (or stays low),
then you will not be able to know of such a presence or number of visitors. To get over
such a limitation, it is advisable to buy models in which camera can be removed &
installed elsewhere (from where there is a better view) or to buy a CCTV camera (39), monitor (42) (your old TV can be
used ) a Doorphone (8) system, separately. The integration of all
these will require professional help.
Advanced Features
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The system can be linked to switch on lights
automatically, though most of cameras are powerful enough to give reasonable picture even
when it is 'near' dark. If such facility does not exist then a PIR can be interfaced to
provide such a facility. |
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There are Infra Red Cameras also available that use
Infrared light to light the field of view. Since Infrared rays can't be seen by human
being, such cameras are good for monitoring without alerting other people. Such technology
is routinely used by armed forces for night vision. |
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Provision of a camera controller with the monitoring
unit giving additional capability to remotely tilt the camera in the vertical and/or
horizontal directions. |
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Color CCTV Camera (39) and
Color Monitor (42) in place of Black and White CCTV camera (39) and B/W Monitor (42) units. |
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Capability for storing the camera image using Video Recorder (47). Storage of image can be useful aid to investigate
a crime later. The advanced recorders allow recording only when they detect a movement. |
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If advanced protection is desired, specially in case
of offices the cameras can be interfaced with recording facility or PC
based surveillance system (86). |
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