Interface apparatus for exchanging different time-critical useful data between a host device and a shared medium , having: a first interface for exchanging the different time-critical useful data with the host device ; a second interface for exchanging the different time-critical useful data with the shared medium ; a resource management device , a buffering device ; wherein the first interface operates with a first clock pulse ; wherein the second interface operates with a second clock pulse , which differs from the first clock pulse ; wherein the first interface and the second interface are connected to the buffering device in order to permit the exchange of the different time-critical useful data between the first interface and the second interface via the buffering device ; wherein the resource management device is configured to control the exchange of the different time-critical useful data between the first interface and the second interface in such a way that collisions of the different time-critical useful data within the interface apparatus and on the shared medium are avoided, in order to permit a deterministic behaviour during the exchange of the different time-critical useful data ; and wherein the resource management device is further configured to control the buffering device in such a way that the different time-critical useful data can be temporarily stored with the aid of the buffering device in such a way that a clock pulse difference between the first clock pulse and the second clock pulse 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 for exchanging the different time-critical useful data with the host device ; a second interface for exchanging the different time-critical useful data with the shared medium ; a resource management device , a buffering device ; wherein the first interface operates with a first clock pulse ; wherein the second interface operates with a second clock pulse , which differs from the first clock pulse ; wherein the first interface and the second interface are connected to the buffering device in order to permit the exchange of the different time-critical useful data between the first interface and the second interface via the buffering device ; wherein the resource management device is configured to control the exchange of the different time-critical useful data between the first interface and the second interface in such a way that collisions of the different time-critical useful data within the interface apparatus and on the shared medium are avoided, in order to permit a deterministic behaviour during the exchange of the different time-critical useful data ; and wherein the resource management device is further configured to control the buffering device in such a way that the different time-critical useful data can be temporarily stored with the aid of the buffering device in such a way that a clock pulse difference between the first clock pulse and the second clock pulse 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. <EOS>