Patent ID: 7129820
Filing Date: 2006-10-31
Classification: G07C,H04L

Abstract:
1. A door station apparatus with an electric lock, having at least one room master station which is installed in a room in order to talk with a visitor, an entrance door station which is connected with the room master station and which serves to call and talk with an inhabitant, an electric lock which is connected to the entrance door station and which is mounted on a door or gate of an entrance, and a power source unit which feeds a supply voltage to the room master station comprising: transmission lines of a two-wire system for transmitting signals and electric power, and for connecting respective sections between said power source unit and said room master station, between said room master station and said entrance door station, and between said entrance door station and said electric lock; an entrance door station side transmitter circuit provided in said entrance door station for the talking with a visitor; and a talk/electric lock changeover circuit provided in said entrance door station, and which, when an AC voltage for a release operation of said electric lock is applied to the transmission line in the section between said room master station and said entrance door station, detects the AC voltage to separate said entrance door station side transmitter circuit connected to said room master station and to connect said electric lock connected thereto through the transmission line with said room master station; whereby said electric lock connected to said entrance door station is permitted to be manipulated from said room master station through the transmission line.