A system of multiple apparatuses for a signalling- and indicating function of a hotel, each apparatus embodying a transmitter possessing an indicator key, a receiver possessing a signal lamp and connection terminals for the infeed of power. According to important aspects of this invention, the transmitter possesses a coding mechanism controllable by the indicator key for simultaneously producing a control signal and at least two address signals, and wherein the receiver possesses a decoding mechanism for actuating a storage. At the output of the receiver there is connected the signal lamp.