The invention relates to a method for the asynchronous serial data transmission between a transmitter and a receiver over a radio transmission link, whereby a synchronization data frame and a carrier recognition frame is arranged in front of the useful data frame. The data frames are each enframed at the beginning and end by a start bit and a stop bit at the beginning and end. The coding of all data frames results such that, in addition to the start and stop bits, an equal number of zero and one bits exists.