each of the four circuit states is able to be characterized by threshold values even if interference voltages occur the threshold values are so far from each other that an unequivocal and reliable recognition of the circuit states is feasible this is a special advantage of this method after recognition of the specific circuit state the drive evaluates the next also as a function of the previous a general data transmission is therefore made possible as well thus not only is information for a stop command a manual control a clockwise rotation and a counterclockwise rotation of the motor able to be transmitted but also even further information such as an error reset or the like this further information is able to be coded clearly and unmistakably in the time sequence of the circuit states the control signal for control 1 is usable for example as a 0 volt or 24 volt signal however other types of signals are also usable according to example embodiments of the present invention systems in which a three phase cable was already installed are able to be retrofitted by using the apparatus described herein and replacing the drive by one as described herein example embodiments of the present invention also provide the advantage that the evaluating.