Abstract: A two-way carrier wave digital data transmission between a terminal station and a central station over low-voltage power line with long distance of transmission and high accuracy at low implementation costs. Long distance of data transmission is achieved by generating a high-energy communication signal by shorting the circuit near the zero crossing of the fundamental power wave, where the attenuation effect on the carrier signal is least. High accuracy of data transmission is achieved by generating a carrier communication signal at low frequency with a triggering/interrupt voltage signal that is much higher than the expected random noise signal in order to have high signal-to-noise ratio at the fundamental working frequency. As a result of the high signal-to-noise ratio, the receiver then can receive the transmitted signal and clearly differentiate between a “1” bit and a “0” bit data.