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Intrusion Alarms | Security Terms

What is a Door Contact Sensor?

February 8th, 2024 | 4 min. read

Isabel Leckie

Isabel Leckie

Isabel is a Marketing Specialist at DGA.

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.

One part of the contact sensor is mounted on the frame while the other is mounted on the moving part of the door. When the door is opened, an alarm condition is initiated. To learn more about the technical details of door contact sensors, check out our blog post here.

There are many different kinds of contact sensors, from mini contact sensors that blend into any setting to rugged metal contact sensors for warehouse settings with rollup doors and gates.

Types of Door/Window Contacts

standard door contact edit


Standard Contact Sensor

Affordable, effective and versatile, these standard contact sensors 
are used for both doors and windows. 

mini contact sensor edit


Mini Contact Sensor

Smaller in size but equally as effective, these mini contact sensors are most often used with windows.

standard recessed contact sensor edit


Standard Recessed Contact Sensor

Popular among businesses where aesthetics is a top priority, these 
standard recessed contact sensors are discreet and unobtrusive. They 
are not suitable to use with metal doors. 

large recessed contact sensor for metal doors edit


Large Recessed Contact Sensor for Metal Doors

Unlike standard recessed contact sensors, these larger 1-inch diameter 
devices can be used on commercial metal doors. 

Metal Contact Sensor for Heavy Duty Doors edit


Metal Contact Sensor for Heavy Duty Doors

These metal contact sensors are made to withstand a high level of abuse. Common use cases are stairwell doors, fire escape doors, delivery doors and hatch doors.  

Metal Contact Sensor for Rollup Doors and Gates edit


Metal Contact Sensor for Rollup Doors and Gates

For rollup doors and gates, we recommend these rugged metal contact sensors that are designed to be installed on the door/gate frame (versus on the ground) to reduce the potential damage to the devices. The larger reed switch is installed on the door/gate frame and the long, narrow magnet is installed on the moving door. 

Safe-Vault Contact Sensor edit


Safe/Vault Contact Sensor

These high-security contact sensors are typically used for safes or vault 
doors to resist tampering attempts. Each contact sensor contains several 
magnetic switches, each with a different polarization. In order to “close” the contact sensor, the opposite piece on the door must contain the matching magnetic fields in the exact same orientation.