The long-awaited HomePlug AV specification for superfast networking through conventional electrical wiring in homes and small offices has been ratified, paving the way for products as early as next spring.

The ratification of the spec was announced this week by the HomePlug Power Alliance, the trade group that developed the original HomePlug specification. The Alliance announced plans for HomePlug AV, the successor to HomePlug 1.0, nearly three years ago, citing the need for networking technology suitable for streaming high-definition TV and other digital entertainment through the home.

HomePlug 1.0 moves data at a theoretical maximum of 14Mbit/s, with real world performance roughly equivalent to the 4.5Mbit/s or so of 802.11b Wi-Fi. HomePlug AV's theoretical maximum throughput is 200Mbit/s; real-world data rates should run between 70Mbit/s and 100Mbit/s, says Andy Melder, senior vice president for strategic business development at Intellon, one of the companies contributing to the spec.

The new spec includes quality-of-service technology to ensure smooth video and audio streaming and 128-bit AES encryption, a more robust security algorithm than the 56-bit DES encryption in HomePlug 1.0, Melder says. In addition, HomePlug AV technology can work over coaxial cable and phone lines as well as over the electrical wiring for which it was designed.

"This is a breakthrough technology eagerly anticipated by the consumer marketplace," HomePlug Power Alliance chairman Pete Griffin says in a statement (Griffin is also director of corporate technology for Radio Shack). "HomePlug AV will change the face of the digitally connected home. It is the first multimedia distribution technology that makes multimedia home networking as easy as plugging an appliance in a power outlet."

Intellon expects to have its first HomePlug AV chips by the end of September; Melder says he anticipates seeing prototype HomePlug AV adapters at the Consumer Electronics Show in January, with commercial ones to follow by early spring. However, he cautions that we probably won't see the first consumer electronics products with integrated HomePlug AV -set-top boxes, digital video recorders, and the like - until a year from now.

Although HomePlug AV is a promising technology, it nonetheless faces some significant challenges in the marketplace, according to Jonathan Gaw, an IDC analyst who tracks the home networking industry.

Technically speaking, Gaw says, HomePlug AV "offers a real alternative" to other networking technologies such as coaxial cables used for cable TV, Wi-Fi, and Ethernet.

And HomePlug AV isn't too late to the party, Gaw says. While Wi-Fi has more or less triumphed as the networking technology for Internet sharing, "when it comes to more advanced applications, like sending video or audio over a home network, it's still very early in the game".

HomePlug AV will also face vigorous competition from cable TV companies, which are likely to promote coaxial cable-based networks as having cleaner signals and better digital rights management technology (something content providers will like). The cable companies are also expected to offer customers cable boxes with built-in routers.

But "cable is a very North American-centric solution", Melder says, noting that cable is not as ubiquitous in homes overseas as it is here. Also, he says, most homes have relatively few cable jacks, while power outlets are fairly plentiful.