Abstract: A method for changing an operating mode of a processing unit of a network node is described. The processing unit is connected to a communication and supply line for providing data communication and for providing a supply voltage. The method includes an establishing of a communication connection of the processing unit of the network node via the communication and supply line, a determination of a change of the supply voltage of the communication and supply line by the processing unit, and a setting of an operation mode of the processing unit based on the determined change of the supply voltage.

Abstract: A computer network for data transmission between network nodes, the network nodes being authenticatable to one another by authentication information of a public key infrastructure, with a root certificate authority configured to generate the authentication information for the public key infrastructure. The root certificate authority is arranged separate from the computer network and is not linked to the computer network. A network node of the computer network comprises an authentication information storage, a processor, a network communication device and an initialization device having an initialization communication device and a temporary authentication information storage that can be read out by the processor.

Abstract: A technique of determining an actual number of passengers on board a means of transport, for example on board an aircraft. A system embodiment comprises a camera arrangement configured to acquire image data on board the means of transport, and a processing unit configured to determine the actual number of passengers on board the means of transport, based on the acquired image data. The camera arrangement comprises at least one of one or more cabin corridor cameras and one or more cabin door cameras. The one or more cabin corridor cameras are configured and arranged to acquire image data of at least one or more cabin corridors of the means of transport. The one or more cabin door cameras are configured and arranged to acquire image data of one or more cabin doors of the means of transport.

Abstract: A computer network for data transmission between network nodes, the network nodes being authenticatable to one another by authentication information of a public key infrastructure, with a root certificate authority configured to generate the authentication information for the public key infrastructure. The root certificate authority is arranged separate from the computer network and is not linked to the computer network. A network node of the computer network comprises an authentication information storage, a processor, a network communication device and an initialization device having an initialization communication device and a temporary authentication information storage that can be read out by the processor.

Abstract: A method for changing an operating mode of a processing unit of a network node is described. The processing unit is connected to a communication and supply line for providing data communication and for providing a supply voltage. The method includes an establishing of a communication connection of the processing unit of the network node via the communication and supply line, a determination of a change of the supply voltage of the communication and supply line by the processing unit, and a setting of an operation mode of the processing unit based on the determined change of the supply voltage.