Abstract: A device for detecting a key inserted into a motor vehicle lock includes a transmitter and a receiver connected to a micro-processor and a circuit connected directly between the transmitter and receiver and bypassing the microprocessor. When the key is inserted in the lock, the key communicates over a communications link with a lock-end interrogation device emitting intermittent interrogation pulses. The receiver activates the circuit upon receiving an interrogation pulse and actuates the transmitter to transmit a response pulse in response to the interrogation pulse. A key has a system for detecting whether it is inserted in a motor vehicle lock and includes a microprocessor, and a circuit connected directly between a transmitter and a receiver for sensing externally fed-in signals and bypassing the microprocessor.

Abstract: An energy coil together with an IR receiver form a mechatronic component of an ignition lock. The component is disposed in a receptacle of the ignition lock such that, with the ignition key inserted the component, it is disposed in close proximity to an energy coil and an IR transmitter of the ignition key and it is aligned with the latter.

Abstract: An anti-theft system for a motor vehicle includes a portable code transmitter which transmits a code signal from a distance upon actuation. A receiver unit in the motor vehicle receives the code signal and evaluates it. Upon authorization, only the engine is started, but the vehicle does not have to be unlocked. A further code signal is required in order to drive the vehicle. However, it must be generated in the vehicle interior. Thus the engine can already warm up without the user being located in the vicinity of the vehicle.

Abstract: A monitoring system for monitoring window panes of an interior of a space or chamber having a plurality of window panes and lateral and/or upper and/or lower walls surrounding the window panes, such as an interior of a motor vehicle to be monitored for intruders, includes at least one microphone configuration for detecting vibrations typically produced when a pane is broken. The microphone configuration is fastened in the interior and/or to at least one of the walls of the space in each case without mechanical contact with the window panes to be monitored, in such a way that the respective microphone configuration can receive essentially only the vibrations transmitted by the air in the interior. The number of the microphone configurations used to detect acoustic vibrations typically produced when a pane is broken and transmitted by the air in the interior is less than the number of window panes and/or door panes and/or roof panes to be monitored for pane breakage.