Abstract: A communication system has a first communication unit and at least one second communication unit. A method for operating the communication system is particularly powerful and at the same time comparably simple to implement. Logical communication connections between the first communication unit and the at least one second communication unit are used for data transmission. At least one keep-alive message, which contains at least one piece of information in respect of a plurality of the logical communication connections used for the data transmission, is transmitted between the first communication unit and the at least one second communication unit via one additional logical communication connection. There is also described a corresponding communication system.

Abstract: A method transmits messages. Accordingly, current information and the information previously transmitted as current information in the previous message is transmitted in each new message. The messages can be transmitted wirelessly or by a cable or wire. The message can be exchanged between rail vehicles and an interlocking, between two or more rail vehicles, or two or more interlockings.

Abstract: A safety-relevant computer system, in particular a railway safety system, contains at least two hardware channels. A memory check results of the channels are fed to at least one comparator, which triggers an error response if the memory check results are not equal. In order to be able to use diverse software programs created by compilers, memory check results of the diverse software programs of each channel are fed to the comparator. The memory check results of a first software program of the first and second channels are compared with each other and the memory check results of a second software program of the first and second channels are compared with each other.

Abstract: A safety-relevant computer system, in particular a railway safety system, contains at least two hardware channels. A memory check results of the channels are fed to at least one comparator, which triggers an error response if the memory check results are not equal. In order to be able to use diverse software programs created by compilers, memory check results of the diverse software programs of each channel are fed to the comparator. The memory check results of a first software program of the first and second channels are compared with each other and the memory check results of a second software program of the first and second channels are compared with each other.