Patent ID: 7796896

Claim:
A method of communicating between a first location and a second location, the method comprising: at the first location, generating output signals having an irregular component, and copying the output signals at least in part such that for each output signal, there is a pair of signal copies, the irregular component being common to each of the signal copies of a pair; transmitting, from the first location, each signal copy of a pair in a common direction over a common communications link; at the second location, mixing data onto the irregular component of a signal copy for at least some of the pairs of signal copies; and at the first location, receiving signal copies from the second location and, for pairs of received signal copies, combining the respective irregular components of the signal copies of a pair in order to extract therefrom data mixed at the second location, wherein the data is mixed at the second location such that between periods when data is being mixed, there are quiet intervals during which data is not being mixed.