What Is CCTV and How Does It Work?

What Is CCTV and How Does It Work?
Oliver Foerstner/Shutterstock

Christin Perry
January 8, 2021

Ever get the feeling you’re being watched? If you’re at a store, business or even a crowded city center, you’re probably right. That’s because closed-circuit television, or CCTV, is likely being used to try and monitor situations and ensure public safety.

But what is CCTV, and how does it work?

What is CCTV?

CCTV, or closed-circuit television, is a video monitoring system in which a recording and/or viewing device is connected to one or more cameras in order to provide surveillance of an area.

CCTV differs from a traditional video system in that it’s not broadcast (thus, “closed”). “The transmitted signal from the camera(s) is not telecast in such a way that anyone can view it like a television broadcast,” said Jack Miller, home improvement expert and founder of the site How I Get Rid Of. “Instead, the signal is usually transmitted to a central control station equipped with monitors [or] digital video recorders (DVRs).”

What is CCTV used for?

CCTV is used for one simple function: surveillance. Aside from providing monitoring services for large, crowded areas, CCTV technology can also be used for private residential security monitoring (often for larger homes), monitoring prisoners, keeping a watchful eye on infants in a hospital and even to monitor a single item, like a highly valuable diamond.

The main difference among all these functions is how many cameras and monitors are involved, who views them and when, and where they’re placed. “The higher the value or the greater the importance, the more likely it is one might want to keep a private record of some persons, property or activities,” said Greg Carson, owner of Carson LLP, an Indiana-based legal firm.

How does CCTV work?

CCTV is a video camera that’s set up to record something, where the output of the video is connected directly to a monitor. “If the video is wireless, or if it’s sent somewhere other than a connected monitor, it can no longer be considered ‘closed circuit (CC),’” Carson said.

CCTV systems can still be quite elaborate with many cameras and even more monitors. Often, a roomful of security personnel provides continuous monitoring of screens that feed real-time recordings from CCTV cameras placed in strategic locations. Recent advancements in CCTV technology include the use of digital technology, which allows for features like motion detection and email alerts. Internet Protocol (IP) cameras are replacing the analog cameras of the past. With the new technology comes high-resolution images, advanced zoom and reposition capabilities, and the ability to use a web browser to view images rather than a simple monitor.

Types of CCTV cameras

What is a CCTV camera? Although CCTV systems work pretty much the same, there are many different types of CCTV cameras. Here’s a breakdown of a few of the more popular types.

Dome camera

Dome cameras are often mounted in the ceiling of large buildings or warehouses, sometimes in rows. They’re meant to provide a broad view of activities in a discreet manner.

Bullet camera

This type of camera is anything but discreet, and is meant to let potential intruders know they’re being recorded. With weatherproof casings, these cameras are most often used for outside surveillance.

Pan/Tilt/Zoom camera

A more modern type of surveillance camera, a PTZ camera can pivot all over the place, providing sweeping views with very few limitations. These cameras also typically feature sharper images than cameras of the past.

Infrared/Night vision camera

This type of surveillance camera is best at recording images in the dark.

Disclaimer: The above is solely intended for informational purposes and in no way constitutes legal advice or specific recommendations.