Abstract: Switching devices in which current contacts are made by actuating a magnetic armature, are tested by analyzing the vibrations or sound emission occurring under operating conditions. According to the present invention, the sound emitted by the switching device when it is actuated is detected by a sensor and is transmitted to an evaluation device for discriminating the time and/or frequency curve of individual sound components. With the process of the present invention, discriminating between the sound signals produced by the making of the contacts on the one hand, and the striking of the armature on the other hand, is possible. In addition, a sound analysis in a suitable time range permits any faults present in the switching device to be classified. Finally, especially in the application to flashing signal relays, whether the sound of the relay is proper, can be objectively determined. In all cases, particularly the high frequency sound components are evaluated.