How a standard burglar alarm bell box works
This bell box is a Pyronix Deltabell, it is a good quality British made bell box, It is modern in it's looks and it also incorporates very modern technology, including Piezo sounders and LEDs to light up the cover. It uses a high voltage driver to make the Piezo sirens work. Applying power to the Piezos without any driver circuitry on it's own won't do anything, since they need circuitry to make the noise for them. The bell box has a Ni-Cd battery in it so it can sound if the wires are cut, this feature is called SAB, or it could be SCB, depending on how you have set the bell box to work.