A converter circuit and method for converting a pulse-width modulated input signal into a voltage output signal eliminates an offset due to component mismatch. The second cam further turning counterclockwise becomes separated from the closing lever and actuates a cam switch at a second angular position to interrupt an electric current supplied to the electric motor. The control frame transmission algorithm establishes the characteristics of a control frame initiated by the station, as well as the characteristics of a response control frame, which is sent in response to a frame received from another station. An eccentric drive acting on the top punch through the lifting rods and the transverse part is provided.