The word CCTV is short for Closed Circuit Television, so when the phrase was coined, it was to differentiate a “closed system”, from broadcast television, which at the time consisted almost entirely of more than-the-air and cable systems.
However, I believe the basic definition – a closed SYSTEM vs. an open or “broadcast” system – still applies regardless of what technology or combination of technologies are used to capture, store, and review an image.
The CIRCUIT, the bond between camera and recorder/monitor, continues to be a direct and customarily un-intercepted path, instead of a broadcast signal where image is simply blasted out far and wide for anyone to receive.
Whether the transmission technique is SDI over twisted pair, IP over WiFi, or NTSC over coax, the reasoning is the same. So in direct answer to the question: CCTV cameras are any which send their signal for an intended recipient using a closed, non-broadcast path.
How CCTV works
There are many different kinds of CCTV systems available? analog and wired, wireless and digital? along with their modes of operation vary; however, the basic components will be in essence the identical:
- a CCTV camera
- a CCTV camera lens
- a CCTV monitor
- cables that carry the signal in one spot to another. (for wired systems)
CCTV cameras work effectively in small facilities because of their limited resolution. You can find number camera home security systems around us that may been seen placed in different places. There are three key components to your CCTV system: the digital camera, the monitor and the hard disk drive that records the images.
Difference between CCTV and IP Camera
Although CCTV is used to reference video surveillance and video security cameras in general, it actually describes analog security cameras which transmit an analog TV signal. In order to be connected to a DVR for recording or a monitor for viewing images, this type of camera uses coax cable and requires a BNC connection.
An IP camera uses an Ethernet cable and transmits an electronic digital signal. This sort of camera can be simply networked and may send a transmission to some network video recorder (NVR) found on a local or remote network.
Each type of camera type has its own cons and pros, but in the main video surveillance is moving over to IP cameras, particularly for business use. They are becoming more popular for home use, as their cost comes down.