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Talking To Your Fridge? You Need In-House Broadband Over Powerline: Page 2 of 10

Those lines run from the headend (i.e., near-end) transformer at the utility substation to the neighborhood (i.e., far-end) transformer that steps the voltage down from the medium voltage (MV) distribution grid to the low voltage (LV, nominally 110 volts in the U.S. and some 39 other countries, and 220 volts or so in much of the rest of the world) that connects to your home or business via a drop cable. At the far-end transformer location, the broadband connection to the premises may be through the transformer (unusual) to the LV drop, around the transformer to the drop via a coupler or extractor, or via a Wi-Fi enabled extractor.

In-house PLC technologies may be more recent that Access BPL, but they aren't exactly new, either. Some key telephone systems and intercom systems have used it for decades. Standards for In-house BPL, a home networking technology, however, are a relatively recent development. Thanks to the HomePlug Powerline Alliance, formed in 2000 by 13 vendors including Cisco and Intel, the HomePlug 1.0 standards, were published in 2001. Those standards are loosely based on Ethernet, as both are based on bus technology, i.e., the use of a shared electrical path, with up to 16 nodes (i.e., devices) transmitting in both directions.

In fact, HomePlug uses the Ethernet framing format, with some modifications. HomePlug compatible devices include PCs, routers, bridges and other devices that use Ethernet, USB and Wi-Fi (IEEE 802.11) technologies. Any such device can plug into standard electrical sockets via a bridge or adapter about the size of a typical power adapter and, thereby, connect directly with the low voltage electric lines (110/220 volts at 50-60 Hz) in your home or office. So every electric outlet effectively becomes a port into a high speed LAN.

The speed rating is an impressive 14 Mbps using the unlicensed frequency band 4.5-21 MHz, according to the standards, with some manufacturers touting much higher data rates using proprietary techniques.