Lily Scherlis at Cabinet Magazine:
The basic function of a doorbell is to facilitate a call and response through walls. Depressing the button, the visitor closes an electrical circuit, sending a signal through the infrastructure toward a piece of hardware that emits noise in the chosen room. In a multi-apartment building, the resident, now aware of the presence of an unseen visitor on the threshold, can press a button that sends a current back downstairs, releasing the door’s lock.
There is a building in the neighborhood of Bötzowviertel in northeast Berlin with a panel of doorbells that make no sound. This special bell board at 35 Käthe-Niederkirchner-Straße is a memorial: the names listed next to the bells belong to eighty-three Jews who occupied the building’s forty apartments prior to their deportation, escape, or death during the Nazi era.
The silent bell board was designed over the past year by Simon Lütgemeyer, an architect who has lived in the building since 1999.
more here.