Communication arrangement for a rail vehicle for operating a mobile radio communication with a track-side facility, wherein the communication arrangement has a vehicle computer, a communication computer, at least one protection facility (31, 32) and at least one mobile radio facility (41, 42) for a radio connection with the track-side facility, wherein the communication arrangement is an ETCS-compatible arrangement, the vehicle computer is an EVC (European Vital Computer) according to the ETCS standard and the communication computer is less secure than the vehicle computer in terms of signalling, and wherein - the vehicle computer and the mobile radio facility (41, 42) are not connected to one another directly, but rather by means of the communication computer and the protection facility (31, 32), - the communication computer is connected to the vehicle computer via at least one computer-side interface (Sr) and to the protection facility (31, 32) via at least one protection facility-side interface (Ssl, Ss2) and - the protection facility (31, 32) is connected to the at least one mobile radio facility (41, 42) via a mobile radio device interface (Sm1, Sm2), wherein the protection facility-side interface (Ssl, Ss2) differs from the mobile radio device interface (Sm1, Sm2) or is operated in a different manner therefrom and additionally differs from the computer-side interface (Sr) or is operated in a different manner therefrom, wherein the protection facility (31, 32) is embodied in such a manner that the following functions are operated in a protected manner: - unsecured EURORADIO protocols for connection-oriented mobile radio communication and for connectionless mobile radio communication, - communication protocols of the respective mobile radio device interface and - communication protocols of the respective protection facility-side interface (Ssl, Ss2) with the communication computer. - the vehicle computer and the mobile radio facility (41, 42) are not connected to one another directly, but rather by means of the communication computer and the protection facility (31, 32), - the communication computer is connected to the vehicle computer via at least one computer-side interface (Sr) and to the protection facility (31, 32) via at least one protection facility-side interface (Ssl, Ss2) and - the protection facility (31, 32) is connected to the at least one mobile radio facility (41, 42) via a mobile radio device interface (Sm1, Sm2), wherein the protection facility-side interface (Ssl, Ss2) differs from the mobile radio device interface (Sm1, Sm2) or is operated in a different manner therefrom and additionally differs from the computer-side interface (Sr) or is operated in a different manner therefrom, wherein the protection facility (31, 32) is embodied in such a manner that the following functions are operated in a protected manner: - unsecured EURORADIO protocols for connection-oriented mobile radio communication and for connectionless mobile radio communication, - communication protocols of the respective mobile radio device interface and - communication protocols of the respective protection facility-side interface (Ssl, Ss2) with the communication computer.