Remote street door control for apartment building - in linked to control stairway lights

摘要

An installation by which the lighting on the stairway of a building is switched on by the operation of a remotely operated control to open the street door to give access to a visitor. A switch unit is incorporated in the common line connected all the units in the building with the door lock interlocked with the stairway lighting switch by measn of a relay or similar device.