Systems and methods are provided for performing operations comprising: accessing, by a transmitter physical layer (PHY) controller, data for transmission to a receiver PHY controller over a network connection; randomizing a delimiter independently of randomizing the data; selecting a disparity reset value based on the randomized delimiter to generate an initial miming disparity; encoding the randomized data based on the initial running disparity; generating a frame that includes the encoded randomized data and the randomized delimiter; and transmitting the frame from the transmitter PHY controller to the receiver PHY controller.