A method and system for verifying the connection-related communications data registered by a network node, where the connection-related communications data are used for the calculation of charges includes establishing at least one predetermined test communication connection. By clearing the predetermined test communication connection via the network node and registering a time of an event, the system and method registers the time of at least one additional event for calculating charges at a predetermined measuring point lying outside of the network node. A systematic temporal measuring error is determined. A reference data record containing time-related data and a connection-related communications data record generated is generated. The method corrects the time-related data of the reference data by the ascertained systematic temporal measuring error and compares the reference data record to the connection-related communications data record to determine if a difference lies within a predetermined range.