A digital communication system for transmitting and receiving video data signals and control data signals over a transmission line comprises an open-loop equalizer circuit and a control data extension circuit. The open-loop equalizer circuit is operable to receive video signals transmitted over the transmission line and output equalized video data signals. The control data extension circuit is operable to inject a boost current at the receive end of the transmission line during a positive transition in the control data signal, and clamp the receive end of the transmission line during a negative transition of the control data signal.