Abstract: Apparatus and method for transmitting data messages between a plurality of stations interconnected by a bus line is disclosed, in which each message includes a frame portion and a data portion. The frame portion represents content and priority information of the data message, and the data portion represents data to be transmitted. At least one station transmits a data message having the frame portion transmitted at a first data transmission rate, and the data portion transmitted at a second data transmission rate which is not less than the first data transmission rate. The first and/or second data transmission rate is adjustable in dependence on a signal quality determined for transmission of a data message.