Door entry system
The entrance telephone system (also doorbell or door bell ) allows the visitor of a property to draw attention to themselves and if necessary to ask for entrance.
functionality
By pressing a doorbell button , which is attached to or near a house door or a courtyard gate, a circuit is closed that activates an acoustic - sometimes optical - signal generator, for example a gong .
technology
An intercom system is operated with low voltage classified as harmless to humans and animals , so no further protective measures need to be observed. Bell sheathed cables (YR), doorbell cables (J-FY) or telephone cables JY (ST) Y are usually used for laying cables . The line connections required for this are usually made with plug-in, screw or insulation displacement terminals that are suitable for the small wire cross-section. In practice, some of the connections are also made by soldering .
Generally insulated bell transformers with a secondary voltage between 8 and 12 volts AC are used as the power source . Since an electric door opener is usually also used, which also draws its power from the bell transformer, this is usually rated at 100 VA . Also to be found are batteries as a power source, this has the advantage that the bell even when a power failure works. In this case, however, since the battery would be used up too quickly, no illuminated bell buttons can be used, and a used battery may not be noticed in good time, so that visitors ringing the doorbell in vain leave even though someone is present.
use cases
Door intercom systems are mostly used in properties where there is no direct visual contact with the door. Today, door intercoms are mostly used, especially in apartment buildings without direct visual contact ; partially supplemented by an image transmission.
terminology
- Floor handle - bell button attached to the apartment door (in addition to the bell button on the front door)
- Door station - several bell buttons located in a housing, attached to the front door; often also contains a button for switching on the lighting and is possibly prepared for the installation of a door intercom
- Door release button - button located in the apartment to open the front door
- Two-wire system - the door station is connected to the bells and the door release buttons in the apartments via a two-wire cable
See also
Web links
Individual evidence
- ↑ Practice electrical engineering . 13th edition. Europa-Lehrmittel , Haan-Gruiten 2015, ISBN 978-3-8085-3266-9 , p. 131 .