doorbell
Sign in to savethumb|Doorbell at the entrance of Chetham's Library, Manchester, England thumb|Sound of a two-tone mechanical doorbell 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 connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security.
Article
8 sectionsContents
- History
- Wired doorbells
- Wireless doorbells
- Musical and continuous power doorbells
- Smart doorbells
- See also
- References
- External links
thumb|Doorbell at the entrance of Chetham's Library, Manchester, England thumb|Sound of a two-tone mechanical doorbell 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 connected to a bell, modern doorbells are electric, operated by a pushbutton switch. Modern doorbells often incorporate intercoms and miniature video cameras to increase security.
==History==