Wireless doorbell to the apartment.
Installation of a doorbell in an apartment : Wireless Doorbell To The Apartment.
Quote from Article entitled Installation of a doorbell in an apartment:
To set the button two wires must be connected to be then connected to its two contacts. The connections are well wrapped by adhesive tape or securely fastened by terminals depending on how it is provided on your device. The button is fastened to the wall with wooden panels.
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