Method for Functionally Secure Connection Identification

A method for functionally secure connection identification for data exchange via a telegram between a source data service and a sink data service, wherein whether the time stamp of an incoming telegram is older than the time stamp of a predecessor telegram is determined, upon receipt of the predecessor telegram a monitoring counter being started and whether the currently incoming telegram has arrived within a monitoring time is additionally determined, where a local time stamp of a local time basis is compared with the associated time stamp of the incoming telegram and whether a comparison difference does not exceed a period of time is determined, a telegram arriving only being accepted as valid if the time stamp of the arriving telegram is greater than the time stamp of the telegram most recently accepted as valid, and data is valid if the checks are positive, otherwise a fail-safe reaction is triggered.