Abstract: A method and device for detecting and locating a fault of a housing comprising: arranging at least two loudspeakers and at least two microphones therein; for each pairing of loudspeaker and microphone and a housing with no faults: measuring a reference frequency response of the sound transmission from the loudspeaker to the microphone; for each pairing and a housing with faults: measuring a present frequency response of the sound transmission; for each pairing: determining a difference frequency response as the difference between the present frequency response and the reference frequency response; for each possible combination of two pairings: calculating a correlation measure between the difference frequency responses of the pairings; and determining the combination with the highest correlation measure and, if the same loud-speaker or the same microphone appears in the pairings of this combination, then locating the fault as proximate to this loudspeaker or microphone.

Abstract: A data processing device having a housing in which are arranged a processor, a program memory connected to the processor and at least one hardware component connected to the processor via a data line and supplied with power via a power supply line, comprises a microcontroller arranged in the housing and having an interface and a persistent key memory in which the public key of a first public/private key pair is stored, wherein a switch controlled by the microcontroller is interposed in the data line, and wherein the microcontroller is configured to receive a signature, generated using the private key of the first key pair, of a memory module detachably connected to the interface via the interface, to verify the signature using the public key of the first key pair, and to switch on the switch in the case of verification.

Abstract: A data processing device having a housing in which are arranged a processor, a program memory connected to the processor and at least one hardware component connected to the processor via a data line and supplied with power via a power supply line, comprises a microcontroller arranged in the housing and having an interface and a persistent key memory in which the public key of a first public/private key pair is stored, wherein a switch controlled by the microcontroller is interposed in the data line, and wherein the microcontroller is configured to receive a signature, generated using the private key of the first key pair, of a memory module detachably connected to the interface via the interface, to verify the signature using the public key of the first key pair, and to switch on the switch in the case of verification.