The system includes microcomputers (MCU) for programming subscriber speech stations (TSP) and the door stations (TST) with individual call numbers. The door station microcomputers store individual call numbers which can be transmitted using associated call buttons. A programming procedure is initiated in the subscriber stations by activating microcomputers to accept and store call numbers and setting up a speech connection to the door stations via the bus (BUS) which is terminated by switching off the message signal. The individual call number is transmitted by operating the associated call button (RT) at a door station. The call number is received by the subscriber station involved in the programming procedure and is stored in its microcomputer as a calling address. The process is ended by operating the programming button (P) and the subscriber station is set into a call wait state.
