Abstract: A method and an apparatus are provided for communicating data in noisy environments. A method preferably includes communicating a first fixed data signal at a first frequency on a first data communications line and communicating a second data signal at a second frequency on a second data communications line. The second frequency is preferably correlated to the first frequency by a predetermined coefficient so as to define a correlation value between the first and second data signals. The correlation value preferably represents a predetermined function. The method also preferably includes determining the correlation value responsive to the first and second data signals. The method can also advantageously include communicating a third data signal at the second frequency on the second data communications line. The third data signal is preferably phase shifted from the second data signal.