straightforward logic circuits such as and gates and inverters one of ordinary skill in the art would understand upon reading and comprehending this disclosure that various embodiments of the combinational logic include various combinations of the illustrated circuits and variations of the high and low logic states 0036 fig7 a c are graphs showing the cross over lock feedback circuit 110 correcting for weak pull ups fig7 a shows the initial low crossover voltage about one volt on the d and d u2212 outputs of the single ended transceiver drivers fig7 b shows the feedback circuit 110 applying a correcting voltage to the transmitter 140 pull up and pull down circuits fig7 b also shows that the correcting voltage is adjusted on a clock period basis because the charge is produced from transitions on the transmission cable 130 detected by the receivers 122 124 126 after about twenty clock periods the cross over voltage is brought back to mid rail 1 5 volts as shown in fig7 c 0037 fig8 a c are graphs showing the cross over lock feedback circuit 110 correcting for weak pull downs fig8 a shows the initial low crossover voltage is higher than mid rail about two volts fig8 b shows the feedback circuit 110 applying a correcting voltage to the transmitter 140 pull up and pull down circuits after about twenty clock periods the cross over voltage is brought back to mid rail 1 5 volts as shown in fig8 c 0038 fig9 is a drawing of a system 900 that uses a differential transceiver interface 905 to communicate over.