The HomePlug Powerline Alliance was formed to develop standards and technology for enabling devices to communicate with each other, and the Internet,
over existing home electrical wiring. One of the greatest technical challenges was finding a way to reduce sensitivity to the electrical noise present on power lines. HomePlug solved this problem by increasing the communication carrier frequencies so that the signal is conveyed by the neutral conductor, which is
common to all phases.

On 18 October 2016, the HomePlug Alliance announced that all of its specifications would be put into the public domain and that other organizations would be taking on future activities relating to deployment of the existing technologies

                                                                                                                                                                                                                                                                                                                                           ------ Adapted from Wikipedia, the free encyclopedia