--- title: DGA Blog | Business Security and Fire Systems | Security Terms (3) description: Security Terms | Our business security and fire systems experts answer the most frequently asked questions, no holds barred. Read on. (3) --- [![cropped-DGA-Security-Logo-nsr-1-1](https://blog.dga.com/hubfs/Assets/logo/cropped-DGA-Security-Logo-nsr-1-1.png)](https://www.dga.com/) Search For: - [Contact](https://www.dga.com/contact/) - [Login](https://connect.dga.com/) - [Careers](https://www.dga.com/careers/) [Get A Free Consultation](https://www.dga.com/free-consultation/) - [Business Security](https://www.dga.com/business-security/) - [Intrusion Alarms](https://www.dga.com/business-security/intrusion-alarms/) - [Video Surveillance](https://www.dga.com/business-security/video-surveillance/) - [Access Control](https://www.dga.com/business-security/access-control/) - [Security System Monitoring](https://www.dga.com/business-security/alarm-monitoring/) - [Environmental Monitoring](https://www.dga.com/business-security/environmental-monitoring/) - [Elevator Emergency Communication](https://www.dga.com/business-security/elevator-emergency-communication/) - [Fire Systems](https://www.dga.com/fire-systems/) - [Design and Installation](https://www.dga.com/fire-systems/design-installation/) - [Testing and Inspection](https://www.dga.com/fire-systems/testing-and-inspection/) - [Fire Alarm System Monitoring](https://www.dga.com/fire-systems/alarm-monitoring/) - [Contractor Support](https://www.dga.com/fire-systems/contractor-support/) - [Industries](https://www.dga.com/industries/) - [Art Galleries](https://www.dga.com/industries/art-gallery-security/) - [Banking and Financial](https://www.dga.com/industries/bank-security/) - [Cannabis](https://www.dga.com/industries/cannabis-security/) - [Hotels](https://www.dga.com/industries/hotel-security/) - [Jewelry](https://www.dga.com/industries/jewelry-security/) - [Nonprofits](https://www.dga.com/industries/nonprofit-security/) - [Offices](https://www.dga.com/industries/office-security/) - [Property Management](https://www.dga.com/industries/property-security/) - [Religious Institutions](https://www.dga.com/industries/religious-institution-security/) - [Restaurants](https://www.dga.com/industries/restaurant-security/) - [Retail](https://www.dga.com/industries/retail-security/) - [Tools](https://www.dga.com/tools) - [DGA Blog](https://blog.dga.com) Search For: [Business Security](https://www.dga.com/business-security/) Business Security [Intrusion Alarms](https://www.dga.com/business-security/intrusion-alarms/) [Video Surveillance](https://www.dga.com/business-security/video-surveillance/) [Access Control](https://www.dga.com/business-security/access-control/) [Security System Monitoring](https://www.dga.com/business-security/alarm-monitoring/) [Environmental Monitoring](https://www.dga.com/business-security/environmental-monitoring/) [Elevator Emergency Communication](https://www.dga.com/business-security/elevator-emergency-communication/) [Fire Systems](https://www.dga.com/fire-systems/) Fire Systems [Design and Installation](https://www.dga.com/fire-systems/design-installation/) [Testing and Inspection](https://www.dga.com/fire-systems/testing-and-inspection/) [Fire Alarm System Monitoring](https://www.dga.com/fire-systems/alarm-monitoring/) [Contractor Support](https://www.dga.com/fire-systems/contractor-support/) [Industries](https://www.dga.com/industries/) Industries [Art Galleries](https://www.dga.com/industries/art-gallery-security/) [Banking and Financial](https://www.dga.com/industries/bank-security/) [Cannabis](https://www.dga.com/industries/cannabis-security/) [Hotels](https://www.dga.com/industries/hotel-security/) [Jewelry](https://www.dga.com/industries/jewelry-security/) [Nonprofits](https://www.dga.com/industries/nonprofit-security/) [Offices](https://www.dga.com/industries/office-security/) [Property Management](https://www.dga.com/industries/property-security/) [Religious Institutions](https://www.dga.com/industries/religious-institution-security/) [Restaurants](https://www.dga.com/industries/restaurant-security/) [Retail](https://www.dga.com/industries/retail-security/) [Tools](https://www.dga.com/tools) [DGA Blog](https://blog.dga.com) [Contact](https://www.dga.com/contact/) [Login](https://connect.dga.com/) [Careers](https://www.dga.com/careers/) Get A Free Consultation - Categories [Subscribe](https://info.dga.com/blog-subscriptions) - [Access Control](https://blog.dga.com/tag/access-control) - [Fire Systems](https://blog.dga.com/tag/fire-systems) - [Intrusion Alarms](https://blog.dga.com/tag/intrusion-alarms) - [Video Surveillance](https://blog.dga.com/tag/video-surveillance) - [Security Terms](https://blog.dga.com/tag/security-terms) DGA Security Blog Our business security and fire systems experts answer the most frequently asked questions, no holds barred. Read on. [Subscribe](https://info.dga.com/blog-subscriptions) - Categories - [Access Control](https://blog.dga.com/tag/access-control) - [Fire Systems](https://blog.dga.com/tag/fire-systems) - [Intrusion Alarms](https://blog.dga.com/tag/intrusion-alarms) - [Video Surveillance](https://blog.dga.com/tag/video-surveillance) - [Security Terms](https://blog.dga.com/tag/security-terms) - [Subscribe](https://info.dga.com/blog-subscriptions) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-fire-watch) [Fire Systems](https://blog.dga.com/topic/fire-systems) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Fire Watch?](https://blog.dga.com/what-is-fire-watch) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) June 6th, 2024 A fire watch is a temporary measure that involves having fire guards at a premises continuously monitoring a building or part of a building to identify and manage fire hazards. Fire guards possess an F-01 certificate of fitness for fire guard issued by the New York City Fire Department (FDNY). Monitoring a building includes detecting early signs of fire, raising an alarm in case of a fire, notifying the fire department, and performing other fire safety tasks as directed by the NYC Commissioner. A fire watch becomes necessary when the fire protection system is under any condition of impairment (such as a broken sprinkler system, standpipe/hose system, fire pump, fire protection water supplies, fire mains, fire alarm systems, etc.). [Read More](https://blog.dga.com/what-is-fire-watch) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-fire-watch](mailto:?body=https://blog.dga.com/what-is-fire-watch) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-electric-strike) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is an Electric Strike?](https://blog.dga.com/what-is-electric-strike) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) May 30th, 2024 Electric strikes are a common locking method used in modern access control systems. They consist of a hinged catch that releases to open the door when an authorized credential is presented to the reader. Electric strikes can be configured to be fail-safe or fail-secure, depending on the type of door they are installed on. Typically, electric strikes are configured as fail-safe to allow for safe exit from the premises. Although electric strikes operate on different hardware than magnetic locks, they follow the same principles of access control. [Read More](https://blog.dga.com/what-is-electric-strike) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-electric-strike](mailto:?body=https://blog.dga.com/what-is-electric-strike) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-access-control-unit) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is an Access Control Unit?](https://blog.dga.com/what-is-access-control-unit) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) May 23rd, 2024 An Access Control Unit (ACU) is a panel to which all door-locking hardware (see Electric Strike and Mag Lock) and credential readers are connected. The ACU functions as the traffic controller as well as the primary power source for all the devices connected to the access control system. [Read More](https://blog.dga.com/what-is-access-control-unit) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-access-control-unit](mailto:?body=https://blog.dga.com/what-is-access-control-unit) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-two-person-rule) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Two-Person Rule?](https://blog.dga.com/what-is-two-person-rule) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) May 16th, 2024 A two-person rule, also referred to as an escort rule, is a highly effective access control security measure that requires two authorized cardholders to be present in order to grant access to a specific area or item, such as a door or display case. This feature is often used to protect sensitive locations like specific doors, product storage areas, vaults and safes, and server rooms. By requiring the presence of two cardholders, the two-person rule ensures an added layer of security, minimizing the risk of unauthorized access or potential breaches. This feature is a great way to layer additional security elements to your physical access control system. While financial services firms, banks, jewelry businesses, cannabis growers and operators most frequently request these advanced features, they offer useful applications in many other types of businesses and buildings. [Read More](https://blog.dga.com/what-is-two-person-rule) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-two-person-rule](mailto:?body=https://blog.dga.com/what-is-two-person-rule) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-authority-having-jurisdiction) [Fire Systems](https://blog.dga.com/topic/fire-systems) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is an Authority Having Jurisdiction?](https://blog.dga.com/what-is-authority-having-jurisdiction) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) May 9th, 2024 Authority Having Jurisdiction (AHJ) are government organizations, offices, or individuals that have the power to enforce and interpret the requirements of a fire code and approve equipment, materials, installations or procedures. They are a critical aspect of ensuring the safety and effectiveness of fire systems and fire system monitoring. By working closely with the AHJ, installers and monitoring centers can demonstrate their commitment to maintaining a safe and reliable system for detecting and responding to fires. [Read More](https://blog.dga.com/what-is-authority-having-jurisdiction) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-authority-having-jurisdiction](mailto:?body=https://blog.dga.com/what-is-authority-having-jurisdiction) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-holdup-button) [Intrusion Alarms](https://blog.dga.com/topic/intrusion-alarms) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Holdup Button?](https://blog.dga.com/what-is-holdup-button) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) May 2nd, 2024 Holdup Buttons are discreet buttons that can be used to alert your monitoring center to an emergency. They silently send a signal to the monitoring center, which will immediately notify the police of the emergency. Due to the serious nature of a Holdup Button alert, the monitoring center will not contact you to check for a false alarm. Your security systems provider will work with you to find a location in your business that allows for the most discretion and convenience. [Read More](https://blog.dga.com/what-is-holdup-button) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-holdup-button](mailto:?body=https://blog.dga.com/what-is-holdup-button) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-credential-reader) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Credential Reader?](https://blog.dga.com/what-is-credential-reader) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) April 25th, 2024 A Credential Reader, also known as a Card Reader, captures an access credential's encoded data and transmits it to an Access Control Unit (ACU). The ACU then determines whether to grant or deny access based on the cardholder's access rights. [Read More](https://blog.dga.com/what-is-credential-reader) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-credential-reader](mailto:?body=https://blog.dga.com/what-is-credential-reader) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-thermal-camera) [Video Surveillance](https://blog.dga.com/topic/video-surveillance) | [Intrusion Alarms](https://blog.dga.com/topic/intrusion-alarms) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Thermal Camera?](https://blog.dga.com/what-is-thermal-camera) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) March 7th, 2024 Thermal cameras are intrusion devices that detect and capture thermal radiation emitted by objects and individuals. Unlike traditional cameras that rely on visible light, thermal cameras use thermal imaging. Thermal cameras detect and measure the heat energy emitted by objects and convert it into a visual representation called a thermogram. Thermal cameras excel in challenging lighting scenarios, including near darkness or adverse weather conditions such as fog, smoke, or haze. This capability makes thermal cameras particularly valuable in applications such as outdoor perimeter surveillance. [Read More](https://blog.dga.com/what-is-thermal-camera) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-thermal-camera](mailto:?body=https://blog.dga.com/what-is-thermal-camera) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-mobile-access-credential) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Mobile Access Credential?](https://blog.dga.com/what-is-mobile-access-credential) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) February 29th, 2024 A mobile access credential is a convenient app installed on your employees' smartphones that allows them to gain access to an access point by simply tapping or twisting their phones near the access point. This technology utilizes BLE (Bluetooth Low Energy) or NFC (Near Field Communication) which offers reliable and accurate access. Mobile access credentials widen your access control options beyond the more common access fobs and cards and can replace or supplement the use of physical access credentials. [Read More](https://blog.dga.com/what-is-mobile-access-credential) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-mobile-access-credential](mailto:?body=https://blog.dga.com/what-is-mobile-access-credential) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-passive-infrared-sensor) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Passive Infrared (PIR) Sensor?](https://blog.dga.com/what-is-passive-infrared-sensor) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) February 22nd, 2024 A Passive Infrared (PIR) sensor is a type of motion sensor. This technology operates by detecting movement within a specific area by measuring the infrared radiation emitted by objects. [Read More](https://blog.dga.com/what-is-passive-infrared-sensor) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-passive-infrared-sensor](mailto:?body=https://blog.dga.com/what-is-passive-infrared-sensor) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-door-forced-feature) [Access Control](https://blog.dga.com/topic/access-control) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Door Forced Feature?](https://blog.dga.com/what-is-door-forced-feature) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) February 15th, 2024 The Door Forced Feature is an important part of an access control system. It is designed to activate an alarm if the door is opened without a valid access card being presented or an associated REX (Request to Exit) signal. This feature is especially useful in case of forced entry by criminals who may forcibly attempt to open the door. [Read More](https://blog.dga.com/what-is-door-forced-feature) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-door-forced-feature](mailto:?body=https://blog.dga.com/what-is-door-forced-feature) [![Blog Feature](https://cdn2.hubspot.net/hubfs/298890/blog-files/blog--cards-feature.png)](https://blog.dga.com/what-is-door-contact-sensor) [Intrusion Alarms](https://blog.dga.com/topic/intrusion-alarms) | [Security Terms](https://blog.dga.com/topic/security-terms) ## [What is a Door Contact Sensor?](https://blog.dga.com/what-is-door-contact-sensor) By: [Isabel Leckie](https://blog.dga.com/author/isabel-leckie) February 8th, 2024 A Door (or window) Contact Sensor is a two-part device mounted on a door or window that causes an alarm condition when the intrusion alarm is armed and the door is open. This alert typically causes an alarm condition and signals the monitoring center to take the next steps. [Read More](https://blog.dga.com/what-is-door-contact-sensor) Share - Close - - - - [mailto:?body=https://blog.dga.com/what-is-door-contact-sensor](mailto:?body=https://blog.dga.com/what-is-door-contact-sensor) [Previous](https://blog.dga.com/tag/security-terms/page/2) [All posts](https://blog.dga.com/all) [Next](https://blog.dga.com/tag/security-terms/page/4) [![DGA Security](https://blog.dga.com/hubfs/Assets/logo/cropped-DGA-Security-Logo-nsr-1-1.png)](https://www.impactbnd.com) 429 West 53rd Street New York, New York 10019 ##### Contact Sales 800 PICK DGA (800-554-5599) sales@dga.com ##### Contact Customer Care [customercare@dga.com](mailto:customercare@dga.com) 800-221-2300 ##### [Business Security](https://www.dga.com/business-security/) - [Intrusion Alarms](https://www.dga.com/business-security/intrusion-alarms/) - [Video Surveillance](https://www.dga.com/business-security/video-surveillance/) - [Access Control](https://www.dga.com/business-security/access-control/) - [Security System Monitoring](https://www.dga.com/business-security/alarm-monitoring/) - [Environmental Monitoring](https://www.dga.com/business-security/environmental-monitoring/) - [Elevator Emergency Communication](https://www.dga.com/business-security/elevator-emergency-communication/) - [Nationwide Service](https://www.dga.com/business-security/nationwide-service/) - [The DGA Vault at 580 Fifth Avenue](https://www.dga.com/vault/) ##### [Fire Alarm Systems](https://www.dga.com/fire-systems/) - [Design and Installation](https://www.dga.com/fire-systems/design-installation/) - [Testing and Inspection](https://www.dga.com/fire-systems/testing-and-inspection/) - [Fire Alarm System Monitoring](https://www.dga.com/fire-systems/alarm-monitoring/) - [Contractor Support](https://www.dga.com/fire-systems/contractor-support/) ##### [Industries](https://www.dga.com/industries/) - [Art Galleries](https://www.dga.com/industries/art-gallery-security/) - [Banking and Financial](https://www.dga.com/industries/bank-security/) - [Cannabis](https://www.dga.com/industries/cannabis-security/) - [Hotels](https://www.dga.com/industries/hotel-security/) - [Jewelry](https://www.dga.com/industries/jewelry-security/) - [Nonprofits](https://www.dga.com/industries/nonprofit-security/) - [Offices](https://www.dga.com/industries/office-security/) - [Property Management](https://www.dga.com/industries/property-security/) - [Religious Institutions](https://www.dga.com/industries/religious-institution-security/) - [Restaurants](https://www.dga.com/industries/restaurant-security/) - [Retail](https://www.dga.com/industries/retail-security/) ##### [Tools & Training](https://www.dga.com/tools/) - [DGAConnect Login](https://connect.dga.com/) - [DGAOneVIEW Login](https://dgaoneview.com/login#) - [DGA Payment Login](https://payment.mydga.com/login.aspx) - [Free System Training](https://www.dga.com/free-system-training) ##### [About DGA](https://www.dga.com/company/) - [Blog](https://blog.dga.com/) - [Careers](https://www.dga.com/careers/) - [Credentials](https://www.dga.com/credentials/) - [Meet Business Insurance Requirements](https://www.dga.com/meet-business-insurance-requirements/) © 2026 DGA Security Systems, Inc. | [Privacy Policy and Terms of Use](https://www.dga.com/privacy-policy/)