Doorbell +
![Doorbell](https://files.cheapies.nz/t/39/79639.jpg?h=d75c6647)
A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord, modern doorbells are generally electric switch.