In a subscriber of a communication system for transmitting data of a data stream in time slots of recurring communication cycles, the communication system includes a communication medium, the subscriber, and at least one additional subscriber. The subscribers are connected to the communication medium for data transmission purposes. To allow better utilization of the available frequency range for data transmission, the subscribers have device(s) for spectral spreading of the data of the data stream before transmission via a certain code sequence and have device(s) for transmitting the spread data in the time slots of the recurring communication cycles. The communication system is preferably designed as a FlexRay communication system, the spread data being transmittable in chronological synchronization in a time slot of the communication cycle by various subscribers of the system. The communication medium is preferably designed as a powerline structure via which the subscribers are supplied with electrical power.