A resistor of a specific value (typically 75 Ohms in video) is connected to both ends of a transmission cable and is referred to as a termination in video. When video from a CCTV camera is sent down the cable, it may bounce back from the unterminated end, resulting in two or more 'ghosts' of the original image appearing on the monitor. This ghost effect, also known as 'edge enhancement' or 'ringing,' appears largely on top of the original footage.

When the cable delivering video signals from camera to DVR is short enough, the video termination problem is decreased or eliminated, resulting in 'crisper' quality film. It also depends on the quality of the CCTV camera, which is source-terminated effectively. The visual quality suffers as a result of video termination. As the length of the transmitting cables increases, this problem becomes more obvious and undesired.

Any CCTV system's end of line resistance should be set to 75 ohm. If you notice any double images or ghosting, it's most likely because two pieces of equipment are connected in series and both have the 75-ohm switch turned on. Only the final piece of gear should be set at 75 ohm.

Read More: How do you set up an auto iris lens?