Magnetic reed switches are used commonly in restaurant equipment. The reed switch is an electrical switch operated by an applied magnetic field. The contacts are usually normally open (NO), closing when a magnetic field is present, or they may be normally closed (NC) and will open when a magnetic field is applied. The switch may be actuated by an electromagnetic coil or by bringing a permanent magnet near it. When the magnetic field is removed, the contacts in the reed switch return to their default position.