His description of how differential signaling is used is totally whacked too. His link to Wikipedia's "Phase Difference" page has "phase" in the title, but is irrelevant to how and why differential signaling is used ("puts the out-of-phase signal back in phase, then compares it to the "real" signal" Huh? Not.). He should have linked to "Differential Signaling" instead. http://en.wikipedia.org/wiki/Differential_signaling