How Do Security Systems Work?

Home security systems are common items in many larger homes throughout the country. What was once seen as a luxury item for the rich and famous to protect their valuable items quickly became normal in many houses. While these systems often vary in terms of complexity and coverage, they all manage to do the same thing: alert you, your neighbors, or the authorities when someone tries to get in when they shouldn’t. However, have you ever asked, “how do security systems work?”

If so, then you are in luck. In this article, I’ll discuss what security systems are, what technology is part of a security system, and the different kinds of security systems available.

What Is a Home Security System?

A home security system is a collection of technologies that protect your home from breaking and entering or theft. These technologies will either set off an alarm, alert local authorities, or alert you when something suspicious or dangerous is happening in or around your home.

A security system is more than an alarm. Proper security systems will monitor and secure entrance points in the home, like doors and windows.

Typical security systems are recognizable to most of us. If you’ve seen an exterior door to a house with a sensor on it or watched a friend rush to a control panel to disarm an alarm, then you’ve seen a home security system.

Many modern systems are getting more advanced, however, in terms of what they protect and how. For example, more people are using security cameras at their doors, or installing interior cameras and sound sensors to protect their how and track criminals should they break in.

People also use security systems just to monitor their house. Interior cameras and monitors are often used to keep track of housekeepers, babysitters, or hired dog walkers.

What Kinds of Home Security Systems are There?

There are several kinds of security systems, with many of them custom-installed based on your needs and your home. However, there are two broad categories that most security systems fall into:

  1. Monitored Systems are the most common systems around. These systems include sensors that track when someone enters the doors or windows of your home and alerts a call center that notifies you and/or the authorities (hence, they are “monitored”).

  2. As opposed to monitored security systems, Unmonitored Systems forego signaling a call center for simply blaring a loud alarm and flashing lights to notify you and the neighbors that your home has been breached.

Within these broader categories you’ll also find a technical breakdown between:

  1. Wireless Systems are typically useful for small homes that need just a few pieces of equipment over small spaces. This equipment is typically unmonitored.
  2. Wired Systems work over your house’s existing current. Most monitored (and some unmonitored) systems are wired.

These different categories often overlap, depending on the home and security needs. Wired systems support monitored and unmonitored security. Wireless more often support unmonitored security systems but are increasingly becoming normal in monitored system installations. Many security systems also have monitored and unmonitored aspects, using high-decibel alarms and call center alerts at the same time.

Components of a Security System

Security systems are just that--systems. That means that they are a series of interconnected technologies that come together to make your home safer through surveillance. Typical surveillance systems include:

  • A control panel, where you can arm and disarm the system. The control panel is also typically where you can set individual alarms, set the time and location for alarm activations, and contact the security company (if you have a monitored system).

  • Movement and portal sensors that detect motion into or throughout the house. These sensors typically serve as the frontline defense for a house, because they will be what detects someone breaking in or moving about your home. These are connected to the control panel and will trigger alarms and/or phone calls upon an invasion of your house.

  • Surveillance cameras. Surveillance cameras weren’t always part of security systems in the past, but they’ve become more common over time as camera technology has advanced.In fact, most burglars point to cameras and dogs as their biggest deterrent to targeting a home for robbery. Since modern cameras are much easier to install in strategic locations, they are popping up as part of security systems to monitor front porches, doorbells, and house interiors.
  • High-decibel alarms and lights. Loud alarms and flashing spotlights are critical parts of unmonitored, and many monitored, security systems. These are connected to the central control panel, which triggers them when sensors or cameras pick up someone that shouldn’t be there.

And while it isn’t a “critical” part of a home security system, you should always have a yard placard and a window sticker from your security service installer or provider. These are proven to discourage burglars, so use this basic item to avoid having to test if your system works.

How Security Systems Work: Bringing it All Together

Now that you understand what types of security systems there are, and what the different components are, I can walk through how they work together to protect a home.

Let’s say that there is an intruder. They’ve tried to enter the window.

  1. A sensor at the window (either attached to the window or tracking motion in the room) notices the breach. If you’ve armed your alarm system, it automatically knows that no one should be moving about.
  2. This alarm sends the warning signal to the central control panel (or other central warning system), alerting that something is in the house that should not be there.

What happens next depends on the type of system installed:

  1. In a monitored system, the central control uses the existing Internet connection or phone lines to make contact with the monitoring service. Usually staffed like an emergency call center, this service will track the alarm and attempt to make contact with you. Depending on their protocol, they may immediately call emergency personnel or attempt contact with you first via phone call or text.

  2. In an unmonitored system, the central control will trip a high-decibel alarm and additional alert strobe lighting.

There are also different mechanisms in place for security systems that utilize security cameras. For example, cameras with motion detection may start recording the moment an intruder enters an area (like the front porch or a side window). The video gained here probably won’t trip an alarm immediately, but can provide evidence in the event of a break in.

Doorbell cameras work much the same way, but will only activate once a doorbell is rung.

Smart Security Systems

Smart technology has expanded the capabilities of most security systems by integrating security into mobile apps and other household services.

The exciting thing about smart home security is that it utilizes the “Internet of Things”, a model of technology where everyday household items are connected to the Internet, and each other. Smart home security often streamlines the connection between wireless security technology by using your local Wi-Fi and a cloud service that lets you connect to the system.

What are the advantages of a smart security system? For starters, since everything is connected to the network, you can monitor the system through the web or through your smartphones with an app. This means enabling and disabling your system remotely or checking out camera feeds.

More importantly, you can connect your security system with other smart devices in your home, like smart electrical outlets, stoves, and fire alarms. This allows you to monitor your home for fires or running appliances and turn them off remotely.

Finally, smart devices often let you set up geo-fencing around your house. This is a digital boundary tied to the latitude and longitude of your home. When you leave that area (tracked through your smartphone), it can automatically lock doors, arm your security system, and turn off the stove or other appliances.

These systems work much in the same way as other systems outlined above. However, they do provide you and emergency responders more data and control over the system, with extra layers of protection and prevention automated for your safety.


A home security system can be your first and last line of defense against burglary. A security system can also be a useful tool to help you take care of your home and keep your family and belongings protected.

How do home security systems work? They work by making sure that no one comes into your home and alerting you or the authorities when they do. With a combination of door and window sensors, cameras, and automated responses, security systems detect when someone unlawfully entered your home. Most importantly, they provide you with the peace of mind you need when leaving on a trip or going to sleep. You can rest easy knowing that your home is safe.

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