Dual contact points work fine! The magnetic
contacts are composed of two pieces: the
reed switch which has the wires from the
door/window sensor attached to it AND the
magnet which has no wires connect to it.
Inside the reed switch are two wires that
touch when a magnetic force is applied
(closed) and separate (open) when the
magnetic force is removed. You can place
multiple magnets along the course of you
window path and each time the reed comes in
close proximity to the magnetics it will
close and you can ARM the system...if a
thief would move or slide the window, the
reed switch would first move away from the
magnetic force of the magnetic contact and
the alarm would sound...even though later it
would pass through the magnetic field of any
other magnetic contacts you mounted. Once
an open is sensed by the Door/Window sensor
it will send a signal to the console, and if
Armed, the system will activate an alarm.