A subscriber of a communication system includes a microprocessor, at least two communication controllers and a peripheral bus. The microprocessor is connected to the communication controllers via the peripheral bus and is also connected via the communication controllers respectively to a communication link of the communication system, via which messages are transmitted. In order to optimize the gateway functionality within the subscriber, a provision is made that at least one of the communication controllers has an active interface via which the communication controller is connected to the peripheral bus and has a logic circuit for independently implementing a gateway functionality.