Apparatus having corresponding methods and computer programs comprise a first first-in first-out buffer (FIFO) to receive and store data from a media access controller (MAC); a physical-layer device (PHY) to transmit a signal representing the data; and a control circuit comprising a read circuit to transfer the data from the first FIFO to the PHY, and a transmit pause circuit to transmit a pause frame to the MAC when an amount of the data stored in the first FIFO exceeds a predetermined threshold.