An elevator system has a central control unit for generating control signals and/or processing sensor signals and controlling functions of the system, a plurality of field devices distributed inside a structure accommodating the system, preferably along an elevator shaft, and a field bus system for interchanging the signals between the control unit and the field devices. Each field device outputs sensor signals generated by a sensor and/or receives control signals to be implemented by an actuator. Data packets including the signals are interchanged in a serial manner between the control unit and all field devices in a summation frame method using a closed ring topology. Each field device has a driver to insert the sensor signals into the data packet or to remove the control signals from the data packet. Data and signal transmission is thereby carried out quickly and safely in a safety circuit of the elevator system.