Modern Video Door Phone
Installation of a doorbell in an apartment : Modern Video Door Phone
Quote from Article entitled Installation of a doorbell in an apartment:
An electric wire bell works from a network. This is both its advantage and disadvantage. On the one hand it is not necessary to constantly monitor the battery charge as on the wireless devices. On the other hand, it will not operate if there is no light. Another disadvantage is a dangerous current, so it is important to be extremely careful while install it.
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