Method for transmission of useful signal in digital communication system, involves transmitting a three-phase signal via data lines when signal level of signal indicator corresponds to two different useful signals at subsequent timings

摘要

A communication system (1) is provided with two communication units (2,3) for transmitting a useful signal over the data lines (5-7) connected to each other. A three-phase signal is transmitted from a 3-phase system via the data lines, when a signal level of a signal indicator corresponds to two different useful signals at subsequent timings, such that the phase signals corresponds to the useful signals, when the 3-phase system rotates at specific angle.