Door call and release installation for communications between visitors and occupants or residents prior to access permission

摘要

The installation has at least one door call point (10), one door bell unit (TK) (20), to which are linked telephone devices (30,40) for connection to the door call point. There is at least one bell pushbutton (16). To the TK unit is allocated a programmable control for connection of the door call point either to a corresponding telephone apparatus or to an exchange of a public communications network (70). The connection is set-up in dependence on preset parameters on actuating the bell pushbutton. The installation contains also a memory (100) for call numbers for each pushbutton.