There are different types of zone setups for each sensor. In the case of a door sensor, the sensor will only cause an alarm if the system is armed. In the case of smoke, CO, flood or temperature detectors these sensors should always be set up as a 24 hour active zone, which means the sensor will always be active no matter the status of the system. Depending on the sensor those zones can be set up as an audible zone, meaning the siren will alert, or as a silent zone, which results in the monitoring station receiving a message about it, and you receiving push notifications through your phone if you have our interactive services set up.