Feldbuszugriffseinheit and methods of operating the same

A method of operating a Feldbuszugriffseinheit (16), via a field bus (4, 6) transmitted messages from the access unit (16) to be monitored, in particular without that the access unit (16) on a data transmission on the field bus (4, 6) participates, the members necessary for interpreting the monitored telegrams field device information is retrieved based on contained in the telegrams identification data from a superordinate unit (34, 24).