Data transmission system utilizing power line of 3-phase alternating current

摘要

A transmitter connected to any phase of a 3-phase alternating current transmits a data subsequent to a lock signal in synchronism with the cycles of the phase. A receiver connected to any phase of the 3-phase alternating current receives a lock signal in synchronism with the cycles of the phase. The receiver receives each data after the receiver is synchronized with the transmitter using the lock signal. The synchronized relation is maintained, that is locked until each data transmission subsequent to a lock signal is terminated. The lock is released upon detection of an end signal added to the last portion of each data or a non-busy signal interval. In the case wherein a data transmission is repeated a plurality of times, a set of signals including a lock signal and a data is repeatedly sent out, interleaved with a non-busy signal interval.