BPL or Broadband over Power Line, is an Internet over high voltage transmission lines approach. The BPL connection is proposed but has not yet been released, as they study interference. BPL would eliminate the need for a separate cable connection to the home. However the actual speed of BPL is still in question, and the speed offered by cable companies varies depending on the cost and the company. However for reference a T1 cable connection operates at 1.544Mbps [see T1 transmit rates].

BPL Access System

National Telecommunications and Information Administration, NITA
This particular report was written in 2004, and there does not appear to be a follow on. So you should expect to see BPL deploy any time soon, or that BPL would be the same from area to area.

NTIA identified three different network architectures used by BPL equipment vendors.
System #1 employs Orthogonal Frequency Division Multiplexing (OFDM) to distribute the BPL signal over a wide bandwidth using many narrow-band sub-carriers.
System #2 also uses OFDM as its modulation scheme, but differs from System #1 in the way it delivers the BPL signal to the subscribers� homes.
System #3 uses Direct Sequence Spread Spectrum (DSSS) to transmit the BPL data over the MV power lines.

Editor note; I'm not sure how well Broadband over Power Line will be adopted. This approach might work well for rural areas which have no cable service. But homes with cable service would have far better bandwidth than receiving broadband signals over a power line. In fact over the years many homes with cable service have been receiving fiber to the home, which would be an almost unlimited bandwidth improvement as compared to receiving signals over a power line. Of course fiber is not yet available in many areas, but many times the fiber is wrapped around power lines allowing companies to run new lines without trenching.

In any case there is no Broadband over Power Line, it's just an idea and is only covered here to indicate that there is no interface standard which defines Broadband over Power Line. In fact there is no working group in a standard's organization that is currently working on Broadband over Power Line.