Interface apparatus (103, 107, 1020) for exchanging different time-critical useful data (507, 507') between a host device (106, 108, 1003a, 1003b) and a shared medium, having: a first interface (104, 109, 1021) for exchanging the different time-critical useful data (507, 507') with the host device (106, 108, 1003a, 1003b); a second interface (105, 110, 1022) for exchanging the different time-critical useful data (507, 507') with the shared medium; a resource management device, a buffering device (200, 1010); wherein the first interface (104, 109, 1021) operates with a first clock pulse; wherein the second interface (105, 110, 1022) operates with a second clock pulse (700a, 700b), which differs from the first clock pulse; wherein the first interface (104, 109, 1021) and the second interface (105, 110, 1022) are connected to the buffering device (200, 1010) in order to permit the exchange of the different time-critical useful data (507, 507') between the first interface (104, 109, 1021) and the second interface (105, 110, 1022) via the buffering device (200, 1010); wherein the resource management device is configured to control the exchange of the different time-critical useful data (507, 507') between the first interface (104, 109, 1021) and the second interface (105, 110, 1022) in such a way that collisions of the different time-critical useful data (507, 507') within the interface apparatus (103, 107, 1020) and on the shared medium are avoided, in order to permit a deterministic behaviour during the exchange of the different time-critical useful data (507, 507'); and wherein the resource management device is further configured to control the buffering device (200, 1010) in such a way that the different time-critical useful data (507, 507') can be temporarily stored with the aid of the buffering device (200, 1010) in such a way that a clock pulse difference between the first clock pulse and the second clock pulse (700a, 700b) is balanced out; wherein, in the interface apparatus, a transmission frame of a collision detection protocol is generated, in which the functionality of layer 2 of the OSI model is extended by a command/response protocol. a first interface (104, 109, 1021) for exchanging the different time-critical useful data (507, 507') with the host device (106, 108, 1003a, 1003b); a second interface (105, 110, 1022) for exchanging the different time-critical useful data (507, 507') with the shared medium; a resource management device, a buffering device (200, 1010); wherein the first interface (104, 109, 1021) operates with a first clock pulse; wherein the second interface (105, 110, 1022) operates with a second clock pulse (700a, 700b), which differs from the first clock pulse; wherein the first interface (104, 109, 1021) and the second interface (105, 110, 1022) are connected to the buffering device (200, 1010) in order to permit the exchange of the different time-critical useful data (507, 507') between the first interface (104, 109, 1021) and the second interface (105, 110, 1022) via the buffering device (200, 1010); wherein the resource management device is configured to control the exchange of the different time-critical useful data (507, 507') between the first interface (104, 109, 1021) and the second interface (105, 110, 1022) in such a way that collisions of the different time-critical useful data (507, 507') within the interface apparatus (103, 107, 1020) and on the shared medium are avoided, in order to permit a deterministic behaviour during the exchange of the different time-critical useful data (507, 507'); and wherein the resource management device is further configured to control the buffering device (200, 1010) in such a way that the different time-critical useful data (507, 507') can be temporarily stored with the aid of the buffering device (200, 1010) in such a way that a clock pulse difference between the first clock pulse and the second clock pulse (700a, 700b) is balanced out; wherein, in the interface apparatus, a transmission frame of a collision detection protocol is generated, in which the functionality of layer 2 of the OSI model is extended by a command/response protocol.