Abstract: A keyboard having a plurality of key fields and a plurality of capacitive elements, which are associated with the key fields, and measuring electronics is proposed. The measuring electronics are implemented for the purpose of detecting a change of the capacitance value of one of the capacitive elements between a non-actuation level, which is in a first capacitance value range, and an actuation level, which is in a second capacitance value range, and then outputting an actuation signal. The measuring electronics are also implemented to detect a change of the capacitance value of the non-actuation level and a manipulation level above the second capacitance value range and to then output an alarm signal. The attempt to manipulate the keyboard can thus be detected on the basis of the capacitance value increase associated therewith.

Abstract: A device for monitoring a space by changing a sequence of a serial interconnection of closing contacts, in particular of cover switches in a security housing, having a series circuit variation apparatus, a security cover, at least two closing contacts, and a protective circuit, wherein said at least two closing contacts each have an open, electrically nonconductive state and a closed, electrically conductive state, wherein said security cover is set up to put each of said at least two closing contacts in a closed, electrically conductive state, wherein said protective circuit is set up to detect an opening of at least one of said at least two closing contacts, wherein said series circuit variation apparatus serially interconnects said at least two closing contacts, wherein the sequence of the serial interconnection of said at least two closing contacts can be changed by said series circuit variation apparatus.

Abstract: The invention relates to a console (1) and a safety console (101) having dual-stage functionality. The console (1) has a key (21) and a contact plate (41). According to one exemplary embodiment, the key (21) has a dual-stage safety shutdown mat (23) on which electrically conductive layers (25, 27) are located. The contact plate (41) has two contact arrangements having electrically conductive safety contact elements (43, 45) and key contact elements (47, 49). The console (1) is configured to connect the electrically conductive safety contact elements (43, 45) by means of the safety contact layer (25) in an inactive state, thus continuously monitoring the presence and active contact state of the key (21) via a safety switch (37). In an active state, the key (1) is configured to also connect the key contact elements (47, 49) via the key contact layer (27) on the safety shutdown mat (23) such that the activation can be registered by an evaluation circuit (53).