CCTV (Closed Circuit Television) means a system where something can be seen in television is a closed circuit (means in a specified area) not everything in the world where, anything can be broadcast over different channels. With development of technology, people wanted to see more pictures in 1 TV screen, so a switcher was developed, which can show 4 pictures in TV one by one / or by QUAD switcher which can show all 4 pictures in 1 screen.
Indoor or Outdoor
Lighting conditions (during day and night)
Indoor Dome Camera
The indoor dome camera is used in 90% of general indoor applications. It comes in a variety of configurations including standard color, Day/Night, and Infrared versions. It can be mounted on a horizontal or vertical surface but is typically ceiling mounted. Lens options on dome camera may restrict their use in certain applications such as requiring more than a 20mm video lens. Dome cameras are a primary choice in indoor camera locations.
Outdoor Dome Cameras
Outdoor Dome Cameras are typically hard shell vandal-roof casings that offer the same versatility in a variety of lens options. Day/Night outdoor dome cameras are common in applications that have entry and exit points with limited lighting during the night.
The Day/Night camera is the best choice for low-light conditions. The cameras are standard color during daylight conditions, the Day/Night camera switches either digitally of mechanically to a low-lux B/W mode.
During No-Light conditions, Infrared cameras provide infrared illumination of the FoF allowing monitoring of areas with no light available. Te IR LEDs are automatically illuminated and the camera switched to the B/W low-lux mode offering camera views in total darkness.
Pan-Tilt-Zoom camera offer the ability to view in all directions and optically zoom in as required. PTZ cameras also include standard color, Day/Night modes, and a few IR PTZ cameras have been introduced recently. The CCTV operator can set the PTZ cameras to automatically rotate to different FoVs. Options include Auto-tracking applications that dynamically track objects in defined areas.
Digital Video Recorders
All Cameras are connected to Digital video recorder, where data is stored in Hard Disk Drive. The DVR output is finally connected to TV / PC Monitor etc. The quality of picture on TV depends upon the resolution of DVR. DVR are also connected to MODEM through Cat 6 cable ( LAN network), and finally the pictures are transmitted to internet via MODEM. These pictures / video can be seen from anywhere in the world on cellphone / PC etc.