staircases and lift lobbies at each floor can be covered. All the sensitive or areas of importance can also have cameras. 
              For outdoor installation box cameras can be used in weather proof housing and wall mount brackets. For indoor installations dome cameras are best. For outdoor either normal cameras or day and night cameras can be used to view in low light conditions. Besides true day and night cameras IR cameras can also be used depending upon the requirement and location. For all outdoor cameras auto iris lens should be used for the varying light conditions. For indoor fixed iris can be sufficient where there is steady light conditions. Variable lenses are available to select the right view. If camera is directly facing outside light as in the case of an entrance door then WDR (Wide Dynamic Range) cameras can be used. If the outside area is too huge to monitor then PTZ (Pan Tilt Zoom) cameras can be used where the camera can be rotated 360 degrees horizontally and 90 degrees vertically and also it can be zoomed to view the far objects near. Where there is a danger of tampering Vandal proof cameras are available.
             The video from all cameras can be recorded on hard disk with the help of a DVR (Digital Video Recorder). DVR helps in multiplexing or showing multiple cameras on a single screen as well as recording the video data. The analogue video signal is converted to digital data and compressed to store data. Motion detection facility is available in the DVR to record only on motion to save hard disk capacity. The display is normally real time and the recording rates can be different for different models from 400 fps/ 200 fps or 100 fps for PAL system. Recording can be set for 1CIF, 2CIF or D1 formats with different levels of quality settings.
          There are two types of DVRs. One is standalone and the other is PC based. PC based DVR provide high quality images and power networking facility. These DVRs can be hooked on to Local Area Network (LAN) or Wide Area Network (WAN) for remote surveillance locally or from any part of the world.
          Coaxial video cables are used to run the video signal. If the distances are high then twisted pair cables or fibre optic cables can be used. If it is difficult to cabling and if there is an existing LAN system then IP cameras can be used. NVR (Network video recorder) is used to view the IP cameras and also for recording.
           Depending upon the requirement one has to select the right cameras with right specifications. The system should be designed properly to cover all the areas that required to be covered with sharp clear image quality and the proper recording setting to retrieve the images in good quality. The positioning of the cameras also plays a major role in the view that we need. Both video and power cables and the power supply should be secured such that no one should be able to cut them or shut down the power supply.

CCTV system stands for Closed Circuit Television. It is used for security and monitoring puposes. The basic system comprises of a camera and a monitor. If there are multiple cameras and video recording is required then we can use Digital Video Recorders.
              If CCTV system is used for security then all the entry exit points for both people and vehicles should be covered with cameras focussing either recognition of faces or number plates of vehicles. Similarly all the doors leading to the protected site from outside should be covered with cameras. With this design whoever enters the protected site is recorded with recognition details. Also all the