A closed circuit television (CCTV) security camera is a good way to ensure safety in a public building, but as with any type of electronic equipment, there are possible performance problems. Such issues include the camera not sending images to the monitoring station, sending blurry images and images flickering on the monitor. Depending on the problem you encounter, there are several solutions.
Check the cables. If any of the cables is loose or disconnected, securely reconnect it.
Check the IRIS mode select switch. If you are using a DC driven auto iris lens, it should be set to "DC" mode. If using a video driven auto iris lens, it should be set to "VI" mode.
Blurry Image - Check the camera's lens for dirt or other contaminants. Use a soft cloth to clean both sides of the lens.
Adjust the focus on the lens until the picture on the monitor comes in clearly.
Set the iris select switch to "ES" mode if you are using a manual iris lens.