This concerns the configuration of a magnetic reed switch, the type used in alarms, etc.
>> Out of the package, not installed with the magnet removed from the reed switch. The switch is open, no contact is made across the leads, infinite ohms.
>> Installed in everyday use. The (door, window or other) portal is closed and the magnet is against the switch. The switch is closed and contact is made, meaning '0' ohms and the circuit is completed.
Is this switch 'Normally Open' (NO), or 'Normally Closed' (NC)?