Synchronous data transmission system utilizing AC power line

A data transmission system utilizing a power line coupled to an alternating current power supply for transmission of data having a plurality of bits, said data being transmitted in synchronism with the cycles of said alternating current power supply, said data transmission system comprising:

• a plurality of transmitters coupled to said power line;
• and
• a plurality of receivers coupled to said power line;
• each said transmitter including:
• synchronizing signal generating means responsive to the cycles of said alternating current for generating a synchronizing signal in synchronism with the cycles of said alternating current,
• data generating means for generating data for transmittal, said data including receiver identifying information for identifying one of said receivers to receive said data being transmitted and control information for representing a control to be made in said one receiver,
• busy state information generating means for generating information representing that said data is being transmitted by said data generating means,
• each cycle of said alternating current comprising a first phase section for transmission of said busy state information and a second phase section for transmission of said data,
• transmitting means responsive to said synchronzing signal generating means of said transmitter, said data generating means and said busy state information generating means for transmitting a high frequency carrier wave signal representing said busy information in said first phase section of each cycle of said alternating current and for transmitting a high frequency carrier wave signal representing said data in said second phase section of each cycle of said alternating current,
• receiving means for receiving said high frequency carrier wave signal transmitted by other ones of said transmitters, and
• transmission inhibiting means operatively coupled to said receiving means of said transmitter and said transmitting means of said transmitter for inhibiting transmission of said high frequency carrier wave signal in response to said busy state information of other transmitters;
• each said receiver including:
• synchronizing signal generating means responsive to the cycles of said alternating current for generating a synchronizing signal in synchronism with the cycles of said alternating current,
• receiving means responsive to said synchronizing signal generating means for receiving said high frequency carrier wave signals in said first and second phase sections of each cycle of said alternating current, and
• decoding means responsive to said receiving means of said receiver for decoding said receiver identifying information and said control information being transmitted and for providing a control signal associated with said control information provided to said one receiver identified by said receiver identifying information.