Honeywell MPS52 Frequently Asked Questions

What Are Door Contacts?
Sensors that are used to monitor whether a door is opened or closed are often called door contacts. Learn about door contacts and how they are used with alarm systems.

What Do Normally Closed and Normally Open Mean?
"Normal" is the normal state of an opening, such as a door. Normally open/closed refers to the state of a contact connected to a door in its normal position.