An electric power transmission system for communications includes on/off switches; high-voltage power assemblies; groups of high-voltage devices each being powered by the high-voltage power assembly; a carrier waves communications network comprising a transformer and filter, a filter, and a carrier waves coupling device interconnecting the transformer and filter and the filter, wherein the transformer and filter includes a low-voltage power assembly for communications and the filter includes a high-voltage power assembly for communications; and low and high-voltage devices. Data can be communicated between the low-voltage devices, between the high-voltage devices, or between the low-voltage device and the high-voltage device by transmitting carrier waves over the AC power.