A serial data communication system (10) comprises—a local clock generation device (12) adapted for generating a clock signal (16) with a duty cycle depending on a control signal (18), and—a serial data communication control device (14) adapted for generating the control signal (18) depending on the receipt of a serial data signal and for deriving a transmit and receive clock signal (20, 21) from the clock signal (16) received from the local clock generation device (12).