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Security System Definitions and Terms

Do you understand what you’re getting with your security system? Are you getting all the sensors you need? Or is the alarm company adding on useless junk? Learn the industry terminology so you don’t get taken advantage of. This page discusses some of the most commonly used home security systems terms and explains what they mean in layman language. After reviewing these terms, visit our Home Security Systems Reviews page to compare the leading alarm providers.

Security System Definitions and Terms

24-Hour Zone: A 24-hour zone is active and functioning 24 hours per day (even when the alarm system is disarmed). Examples include smoke or carbon monoxide detectors, panic buttons and low temperature sensors.

Access Code: A code that home security system users can use to arm and disarm their security systems. Access codes are usually four digit codes and can be individualized to specific users such as maids and children.

Arming: Arming an alarm system means turning on the system so that it is actively monitoring the home. Some home security systems allow for full or partial arming of the system. For instance, if your bedrooms are upstairs, some systems allow for the arming of only the downstairs area of the house, so you are free to move around upstairs.

Arming Away: Away arming refers to arming the home security system completely so that the entire home is protected when the homeowners leave the house. Generally this means that all of the motion detectors are activated.

Arming Stay: Stay arming is a method of arming the house alarm system when the homeowner intends to stay at home. This type of arming will activate the exterior sensors of the home such as doors and windows but will not arm the interior components of the home security system such as interior motion detectors.

Backup Battery: This is a rechargeable battery that provides power to the home security system in the event that the AC power is no longer functioning. This battery is usually found in the control enclosure of the alarm system and on occasion it may also provide additional current to the alarm system if needed. The backup battery is also often referred to as a standby battery.

Bell: This term is used in the security system industry to refer to any sound made by the device, rarely are these devices actually bells. They are most often sirens that either speak or make a loud noise to indicate that the alarm is armed or that the alarm has been set off. The term bell originates from the primitive home alarm systems which actually did use bells on the outside of the building.

Bell Cut Off: The term bell cut off refers to the amount of time that a “bell” will ring before it shuts off automatically. This may seem counter-intuitive, however, many areas require cut off times of five to ten minutes after the alarm has sounded in order to prevent nuisance noise complaints.

Bypass: This term is in reference to the ability to deactivate specific zones of the building or home before arming the system. Bypassing allows for certain areas of the home to be unmonitored while the rest of the home is monitored.

Carbon Monoxide DetectorCarbon Monoxide Detector: This device detects the presence of carbon monoxide and will sound an alarm before a dangerous level is present. Most detectors are used without being connected to the alarm system, they provide an audible warning to the home owner. When the carbon monoxide detector goes off, open as many windows as possible and vacate the house. If anyone is sick (headaches, dizziness or vomiting), call 911 immediately. If everyone is okay and out of the home, call the gas company and they will advise the best procedure to move forward.

Cellular Monitoring: Some home security systems use a cellular transmitter that uses a cell phone line to call the monitoring station rather than a landline or broadband communication method. In the past, cellular monitoring services were used primarily as a backup option with landline phone service being the primary means of communication for the alarm system, but more companies today are transitioning toward 100% cellular monitoring in the interest of added security. Teh advantage is that there is no risk of intruders cutting the communication line since it is there is no physical line.

Central Station: The term “central station” is used interchangeably with the term “monitoring center.” This refers to the location that alarm monitoring companies use to monitor alarm systems. There are a number of ways that personal home security systems can communicate with central stations including telephone lines, broadband internet or cellular communication. This central monitoring station is responsible for contacting the correct emergency services in a timely manner in case of an alarm.

Chime: This refers to the sound that home security systems can be programmed to make whenever a door or window within the home is opened or closed. This type of sound allows for homeowners to monitor comings and goings in the home.

Communicator: This is a module within the home security system that digitally dials in to the central station. The communicator is responsible for relaying information about the home that is ascertained by the home security system.

Contacts: These are the small sensors that are placed on doors and windows of the home so that the home security system can monitor whether a door or window is open or closed. The most common type of contact used in modern alarm systems is a magnetic reed switch.

Touchscreen PanelControl Panel: This refers to the main components of the alarm system which contain the backup battery and the main circuit board of the system. These component’s are contained within an enclosure. In some alarm systems the keypad is integrated into the control panel as well, but this is not the case with all systems.

Disarm: Disarming a system means turning the system off. This does not mean removing power to the system but it does mean that the system is not actively protecting the home against break ins or other emergencies. Please note that disarming an alarm system will not disarm 24-hour zones such as panic buttons and smoke detectors.

Door or Window SensorDoor and Window Sensor: These sensors are usually two parts. One sticks to the door or window, while the other sticks to the stationary part of the home. There is a magnetic connection, so when the connection breaks, the alarm knows that the door or window is open.

Entry Delay: A time delay that allows the homeowner a period of time before the alarm triggers due to an event. This is most commonly the period of time that allows for homeowners to get into the home to turn off the alarm system before it sounds. Most systems default to a thirty-second delay.

Exit Delay: This is the delay after an alarm is armed which allows the homeowner to exit the home before the system becomes active. Like the entry delay, this can also be adjusted to meet the homeowners specific needs.

Flood SensorFlood Sensor: This component detects the presence of excessive water so that it can alert the monitoring station of a potential flood concern. The flood sensor is often placed near the water heater since that is the most likely area for flooding to occur. Other common places for flood sensors include: in or beside a basement sump pump pits to alert you of a defective or non-functioning pump before your entire finished basement gets flooded; behind the washing machine to alert if a hose has burst.

Freeze SensorFreeze Sensor: More commonly known as a “Low temperature sensor”. This element detects temperatures that are approaching freezing, generally close to 40 degrees. This way you are alerted before an actual freeze occurs in the home that could cause damage to pipes or other important parts in your home. It can also detect issues with a furnace that may not be operating correctly.

Geo-Services: Used in home automation. is the only security provider that has geo-services and allows your home to adjust automatically based on your GPS location on the phone.

Glassbreak SensorGlassbreak Sensor: This component detects the sound or vibration from shattering glass to trigger your alarm. This can be an excellent alternative to normal window sensors when you have a window at floor level that is more accessible by intruders or one that contains more glass such as french doors or a bay window.

Hardwired System: This is a system that is installed using physical wires, often hidden mostly behind the walls of the home. Most older home alarm systems rely on hard wiring where most new systems are gravitating towards wireless or hybrid alarm systems.

Smoke and Heat SensorHeat Detector: This alarm component detects extreme or rapid changes in heat within an area of the home as a detector for fire. Heat detectors can also be pre-programmed to sound at a specific temperature. It is important to know that a heat detector is not the same thing as a smoke detector. It is possible for a smoke detector to have a heat sensor built into it.

Hybrid Alarm System: This is a home security system that utilizes both hardwired and wireless components.

Image Sensor: A motion sensor with a built-in camera that can send photos captured when the motion sensor is triggered to your interactive smart device.

KeypadKey Pad: Also referred to as a touchpad, the key pad of a home alarm system is the numbered pad on the system that allows for the homeowner to arm, disarm and otherwise communicate with the alarm system. Most key pads have lighted keys and accompanying chimes that sound when keys are pressed.

Master Code: A master code is the main code used for an alarm system that the homeowner uses to arm and disarm the home security system. The master code for an alarm system has the ability to control other sub-codes of the system. The master code, like the access code is usually a four digit code.

Memory: As with other electronic devices, alarm systems can have built-in memory. This memory is used to store information about the most recent alarm events that have taken place in the home.

Motion SensorMotion Sensor: These usually detect motion based on body heat in a 90 degree angle and generally up to 45 feet away. Every company’s motion sensors differ, so it is best to read your specific instructions for your system to ensure maximum coverage.

Panel: The panel of a home alarm system is the box or “can” that contains all of the components of the home alarm system such as the backup battery and the main circuit board. Most often the panel of the home alarm system is located in a basement or in a coat closet of the home.

Periodic Test Transmission (Also known as Pinging): The alarm control panel can be programmed to send “test signals” to the monitoring station at a scheduled frequency. Some security companies do this automatically, so be sure to check with your provider. This is an especially useful alarm panel function since most homeowners do not regularly test their alarm system’s ability to communicate to their monitoring station. To take full advantage of this option, have the installer program the alarm system for a periodic test transmission once every 24-hours. Then make sure that your alarm service provider will notify you when your alarm panel “misses” its daily test so that appropriate action is immediately made to correct any issue. Also pay attention to the trouble indicator light on your keypad(s) since it will be lit if your security system cannot communicate to your monitoring station.

Important information: a periodic test transmission once every 24 hours is only a useful tool in confirming the alarm panel’s ability to “talk to the monitoring station”. It does not remove the homeowner’s responsibility of testing each of their alarm system’s individual sensors on a regular basis to confirm that each sensor or device is “still talking to the alarm panel”. If a monitored smoke detector does not “talk to” and trip the alarm control panel, the control panel will not call the monitoring station.

Programming: There is User Programming and Installer Programming.

User Programming refers to the ability of the homeowner to set behavioral characteristics of the home security system. An example of this is the ability to program the system to chime or not chime when doors and windows are opened. 

Installer Programming refers to the ability of the installer (who may also be the homeowner who self-installs an alarm system) to set characteristics of the security system that customize and configure it according to the home or business. An example of this is the ability to program the system to define Zone 1 as being a smoke detector, a door contact or a motion detector.

Security Phrase: This term varies by alarm company (Pass Phrase, Security Code) but it is usually a word or short phrase that only the homeowner should know. When the monitoring station calls to report an alarm, the person answering the phone can declare it a false alarm as long as they provide the correct security phrase.

Security System: The term “security system” is used interchangeably with the term “alarm system” and refers to all components of the system that protect the home.

Smoke and Heat SensorSmoke Detector: This component detects the presence of smoke in the home. Smoke alarms sound their own high decibel warning. Many smoke detectors are used without being connected to the alarm system. When moving into a home with an existing system, be sure to confirm that all detectors are connected to the alarm system or at a bare minimum that one close to the kitchen is monitored with your home security system (can get expensive to monitor all).

Test Mode: An alarm system owner can call their monitoring company and have them put the system in test mode. Once in test mode, the owner can set off the alarm and then call the monitoring station to make sure they received the signal.

Voice Dialer: This component will automatically call in to telephone numbers that are programmed into the system. After calling the numbers, the voice dialer will play a recorded message (or a live person will be on the line) once the home alarm system has been triggered to notify the individual answering the number of the event that has been triggered. New systems also have the ability to send text messages and emails in alarm situations.

Wireless Alarm System: A wireless alarm system depends upon radio  frequency to transmit and receive signals from the home alarm system. These types of systems are easier to install and generally preferred by homeowners because they do not involve running wires in the home. All of the sensors are wireless as well and these components can be used as additions to wired alarm systems to create a hybrid alarm setup.

Zone: This term is used to refer to an area of the home as it is “seen” by the home alarm system. This type of area is generally determined by numbers and is mapped out by alarm components like the sensors in a particular area of the home.

Each zone is specifically defined by the alarm panel’s “reaction” to the sensors on the zone.  A “24-HOUR FIRE ZONE” for a smoke detector will pulse the alarm’s siren(s) when activated, at any time, whether or not the alarm system is armed.  Other common alarm panel zone definitions, such as “DELAY ZONE”, “INSTANT ZONE” or “INTERIOR ZONE” have different “reactions” from the alarm panel when these zones are “tripped” or activated.

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About Kimberly Alt
Kimberly has always taken security seriously. Whether it's making sure she locks all the doors or using complex passwords, she tries her best to live a secure life. She has years of experience with testing, reviewing, and writing about security systems. One of her favorite parts of her job is being able to inform consumers of the best security products available.
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  • a Security Professional

    Hi Amy,

    This is very well organized and informative!

    I've included some additional information that you may want to use in your article:

    Heat Detector:  When a heat detector goes into alarm, there is already a considerable fire in the room since most heat detectors actually “activate” by melting at 135 degrees Fahrenheit or higher.  Therefore, a smoke detector which provides early detection of a fire is a life-safety device, while a heat detector is not.

    Programming: More info on "User Programming" refers to the ability of the homeowner to set behavioral characteristics of the home security system. An example of this is the ability to program the system to chime or not chime when doors and windows are opened.  "User Programming" cannot affect the important security features of the alarm system which are only accessed through "Installer Programming".

    Smoke Detector:  Most insurance companies only require that at least ONE smoke detector be connected to a monitored alarm system in order for the homeowner to obtain a reduction in their insurance policy.  It is usually a more expensive option to have ALL of the home’s smoke detectors connected to the alarm system, which is why most homes do not have ALL of the smoke detectors connected to the alarm panel.

    • A Secure Life

      Thank you so much for this and all your continued feedback that makes our website a stronger resource to our readers. We have incorporated (or are in process of adding) all of your suggestions provided for this page and appreciate your help. Take care!

  • Jason

    I am researching home alarm companies and was curious what all these terms meant. Thank you for sharing these so I don't look like such an idiot – as it can be overwhelming when you think of all the new words and what they all mean and do to protect your home. 

  • Peter

    I am researching getting a home alarm system so this list of terms and tips is very useful as I was clueless on home security systems before I started this process. I want to understand exactly what I am getting and making sure I know how to best make the most informed decision in regards to my home. One thing I have a question about though is "Smash and Grab" I keep seeing this term and don't understand what it means. Can anyone clarify that for me? Thanks!  Keep up the great work. 

    • Steve

      My understanding of smash and grab is that if the technology is activated on an alarm system, a burglar can destroy the control panel and the monitoring station will be notified of this event and will dispatch the police. For systems that do not have smash and grab (which I believe is most systems), once the burglar damages the control box, the signal to the monitoring station is lost and the authorities will not be contacted.

      • a Security Professional

        Hi Steve,

        Let me make things clearer for you.  The descriptive words in the different terminologies help to describe the event.

        “Smash and Grab” refers to a robbery where a criminal quickly leaves before authorities arrive.


        • A jewelry case is “Smashed”.  The crook “Grabs” a necklace and runs.
        • Your patio door is “Smashed”.  The burglar “Grabs” your laptop and leaves.

        Alarm systems are ineffective against “Smash and Grab” attacks.  Important small items such as laptops, car keys and jewelry (that can quickly be removed) must be locked away and/or hidden.  If you absolutely want to retain ownership of any small item, it must be secured in a manner that takes the thief a longer time to find and acquire, than the time it takes for the Police to arrive.

        Now let’s move on to alarm systems:

        Crash and Smash” technology is NOT an indication of one alarm system necessarily being superior than another alarm system.  The expression “Crash and Smash” refers to a technique that criminals use to defeat ONLY a badly designed or a poorly installed alarm system.

        ANY competent security professional (or homeowner with the proper knowledge) can install an alarm system that will NOT succumb to a “Crash and Smash” event.

        Here’s how “Crash and Smash” works:

        The criminal will “Crash” down the front door of a home which has an armed alarm system.  Opening the front door usually starts the entry delay so that the homeowner can disarm the alarm system.  During the time that the entry delay is active, the criminal will try to find the alarm’s control panel and “Smash” the alarm’s communicator before it can make its call to the monitoring station.

        "Crash and Smash" attacks typically try to exploit the entry delay on the front door contact.  This is because some alarm systems will make ALL of the motion detectors in the home follow this entry delay.  This basically boils down to no security for the alarm communicator while an entry delay is active.  Therefore, you must take additional steps to compensate for these alarm systems.  Example: Lock the alarm communicator in a room on a separate partition.  This room is not considered part of your home alarm system, which means that the room will still be armed when your home is disarmed.

        Installing the control panel in the basement where it's easily seen through a window is not a good idea.  If you're at home sleeping, any motion detectors in the basement (which may provide some security for the control panel) are usually automatically bypassed in STAY mode.  This means that a criminal can now Crash a basement window while you're at home and have direct access to Smash your control panel.

        The very simple solutions to installing ANY alarm system that is resistant to a “Crash and Smash” attack are:

        1. Installation: Hide the alarm communicator so that it is difficult to locate.  It should take a LONGER time to find the alarm communicator than the entry delay on your front door.
        2. Equipment: Select an alarm system that has a zone defined for motion detectors which DOES NOT follow the entry delay.  This means that after your front door is kicked in, any motion detectors which are in the interior of the home will be instantly activated, creating an alarm BEFORE the criminal finds and attacks your alarm’s communicator.
        3. Monitoring transmission: To ensure that an alarm is transmitted, use a wireless transmission means to the monitoring station.  Cellular and radio transmissions fit this bill perfectly.

        It also helps to program the shortest time necessary for any entry delays.

        A “Crash and Smash” attack can only take advantage of a poor security system installation where no alarm devices are activated before the alarm panel is destroyed.

        It's the installer's fault for not properly planning a defense against "Crash and Smash".  The actual alarm equipment is rarely to blame, although there are “crap alarm products” such as a self-contained keypad installed at the front door with telephone line monitoring, that are worthless pieces of junk.  But a good security professional would NEVER touch this stuff!

        Once you understand the steps behind a “Crash and Smash” attack, the proper selection of alarm equipment, correct installation technique and choice of transmission method to your monitoring station will prevent your alarm installation from becoming a victim.

        The fact that FrontPoint offers “Crash and Smash” does NOT make their alarm system superior to other alarm systems which do not have this “technology”.  FrontPoint is not exclusive in offering “Crash and Smash” detection and prevention to clients.

        Did you not think that banks and jewelry stores have had this obvious criminal technique "covered" for many, many years before the term “Crash and Smash” became part of our vocabulary?

        In order for FrontPoint’s “Crash and Smash” technology to actually work, two conditions must be met:
        1. The alarm system MUST be armed.
        2. The entrance door MUST be opened before the communicator/keypad is attacked.

        As with ANY alarm system, if the FrontPoint communicator gets attacked BEFORE a transmission is made, there is no "Crash and Smash".

        If you elect to go with FrontPoint, my professional recommendation is to hide their communicator/keypad somewhere in your home and install a secondary keypad at your front door.

  • Paul

    These terms are very useful, but the biggest takeaway from this article for me is if you have moved into a home and the security system was already installed, I cannot stress enough how important it is for you to confirm that all of the detectors are connected to the monitoring system. I recently moved into a new home (renting) and the homeowner went ahead and continued to pay the monitoring fee.

    When I moved into the home, I put the system in test mode, set off the security alarm and confirmed that the monitoring station received notice. Life is good. We have smoke detectors around the house and some look different than others, but I didn't think much about it. A month goes by and I set the smoke alarm off from burning something in the kitchen, I spent a few minutes opening windows and waving towels and it finally went off. The bad news was that the monitoring station never called!

    After a lot of investigating, it turns out that the smoke detector by the kitchen was not connected to the alarm system! It was put in by the home builder as just a 'noise maker'! My landlord didn't even know about this. We could of had a major disaster on our hand had I been away from the home and it was an actual fire.