Abstract: The present invention relates to a method of communicating data between at least two units (1) on a serial bus (2) in a car, wherein the units 11) have independent clocks, the data being transmitted as a sequence (3) of frames (4), each frame including an identifier field (9) and a data field (10). In order to ensure an always reliable and synchronized communication of data on a serial bus with different types of units (clocks) where randomly distributed periods of idle time may occur on the bus it is suggested that prior to any sequence (3) of frames (4), a signal pattern (7) is transmitted on the bus (2), so as to set the bus to a definite state for a predetermined period of time.