The present invention is drawn to an electrically “closed” method and apparatus for transmitting and receiving data signals over a high voltage power line. Inductive coupling is employed for coupling and decoupling the data signal directly on to and off of a single power line wire. An exemplary device...http://www.google.es/patents/US7046882?utm_source=gb-gplus-sharePatente US7046882 - Power line communication system and method
