Installation of a doorbell in an apartment : Wall Dowels
Quote from Article entitled Installation of a doorbell in an apartment:
Standard wiring circuit of a doorbell exactly copy the common switch circuit, and it is known, it is the easiest of all the existing electric circuits. The only thing is that a sound mechanism is used instead of light bulbs and a button - instead of switch. Zero connects to the sound panel and the phase - to the button. In this case both elements are also interconnected. Pressed the button, the phase closes and the bell rings.
The full version of the article can be found here.