The system has a subsystem (10) with a sensor (S) detecting physical surrounding conditions and/or an actuator (A) transferring signals to a building-technical functional unit e.g. heating system. The sensor and the actuator are coupled with a processor device (20) for processing the signals and/or for forming an actuator signal. A wireless information transmitting- and/or receiving device (30) is coupled with the device (20) to transmit and/or to receive the sensor and/or the actuator signals. The subsystem operates a bi-directional data exchange with additional subsystem.