Digital transmission method

Data transmission procedure between a reference equipment and a follower equipment, such as a microcircuit card and a read / write terminal of said card, characterized in that it comprises the following stages consisting of: (a) grouping, in a sending equipment , the elementary data of a message to be transmitted in the form of a series of at least one elementary data consisting of a continuation (12) of elementary numerical signals (b0, ... b7). (b) transmitting to a receiving equipment said series (12) of elementary numerical data preceding it with synchronization signals (10) that constitute, with the series of elementary data, a frame (8), the characteristics of duration and position of the elementary numerical signals (b0, ... b7) of each elementary data and the synchronization signals (20, 22, 24, 26) are specific to the reference equipment and known to the follower equipment.