The present invention relates to a data transmission system including a data exchange unit; wherein, to transmit a data frame, it passes successively at least through an interface module that is configured to receive said data frame from outside the transmission system; an analysis and filtering module responsible for processing said data frame which is received from the interface module before encapsulation; and an encapsulation module responsible for encapsulating said data frame processed by the analysis and filtering module, wherein two successive modules through which said data frame passes are connected to one another by an interconnection device each including a temporary memory for storing said frame and the read and write accesses to said memory being frequency-independent.