bears at least one item of information which relates to a user call code kb which can be read by the identification read out device l the user identification card a can comprise a magnetic data carrier but it could also comprise a holographic data carrier furthermore as known per se it is also possible to design the user identification card a as a data carrier which has a structured surface in which case the information is contained in the surface structure the subscriber terminal device t into whose identification read out device l a user identification card a is inserted automatically accepts the user code kb which is assigned to the user identification card a in question however in accordance with the invention a plurality of user identification cards a can be input into the subscriber terminal device t the subscriber terminal device t also includes its own individual subscriber terminal device call code kt which can be permanently assigned to this subscriber terminal device t the input user call code kb is transmitted to a terminal device storage unit tsp individually assigned to the subscriber terminal device t where the same is stored as also illustrated in the exemplary embodiment shown in fig3 the terminal device storage unit tsp is preferably installed in the subscriber terminal device t the input user call code kb preferably together with a location code ks assigned to the location of the identification read out device l being used is transmitted to a central or sub central land based storage device si which communicates with the vehicle v via a radio link where such information are stored at.