The data incoming via the Ethernet connector 12 are monitored by a firewall 14 using firewall rules 16. Only authorized queries or data are passed through by the firewall 14.

Once a query has passed the firewall 14, it is possible to access functional blocks that are disposed above one another hierarchically after a further authentication. In this respect, a web server 20 is arranged in a topmost level, i.e. the fourth level 18. A monitoring service 24 is associated with the third level 22 below it. The access to an application program can also be associated with the third level 22.

The second level 26 is provided beneath the third level 22 and the operating system kernel 28, i.e. the runtime, is associated therewith. The lowest and thus first level 30 comprises a functional block for hardware access 32.