A synchronous data transmission system for transmission of data between two communication partners, of which one serves as a transmitter and one as a receiver, comprising a clock signal producer which produces a transmission clock signal with a transmission clock signal rate from the transmitter to the receiver, which during the occurrence of one of the events equals an event specific transmission clock signal rate associated with the arising event and during an event free period of time equals a fundamental clock rate different of all event specific transmission clock signal rates.