An electrochemical sensor element for determining the oxygen concentration in exhaust gases of internal combustion engines is described. Virtual age is utilized to estimate the degree of degradation of the fluid. An output port of the first stage is connected to an input port of the second stage. A device isolation layer is preferably formed to define active regions. In the second position, the flux density is increased above the threshold level. Before the structuring or configuration of the telecommunications network, it is decided whether this structuring or this configuration of the access network connection should be initiated through the telecommunications network or through the terminal, and that the terminal is notified of this decision by the telecommunications network in one or more messages.