Door Contacts are usually fitted to the front and back doors of a property. Primarily these are used to start the entry time into the premises once the system has been set.
On opening the door this will then give you 30 seconds to turn the alarm off. Once the 30 seconds expires, the system will go into full alarm. If the alarm is in the unset mode and the door is opened a “door chime” can be heard at the alarm panel.
These sensors are available in white or brown.