Power-line networks -- networks that use the existing electrical wiring in your residence or small office -- may yet prove the dark horse of home networking technologies.
That's the message emerging from the HomePlug Powerline Alliance's annual technology conference in California, which wrapped up Thursday. Taking center stage this year were the first products based on the group's HomePlug AV standard, which was ratified more than a year ago. Promising theoretical throughput of up to 200 megabits per second (and real-world speeds approaching 100 mbps), HomePlug AV will be competing with other technologies as the best way to stream multimedia -- specifically, high-definition video -- throughout the home and small office.
Competing with wireless
Power-line networking supporters are hoping to gain traction as people begin to acknowledge wireless networking's limitations for high-bandwidth applications that require quality-of-service features -- meaning the ability to prioritize packets so that streamed video or audio plays smoothly. The problems with products based on the first draft of the high-speed 802.11n Wi-Fi standard may also play to power-line networking's advantage.
Due in stores by year's end, the first HomePlug AV products will be simple ethernet adapters, small bricks that plug into an ethernet port on one end and a standard electrical outlet on the other. Setting up a network requires at least two such adapters: one to plug into an Internet-connected router, and another to plug into the ethernet port of whatever device you wish to put on the network.
First AV products
Zyxel, one of the exhibitors at the HomePlug conference, will be among the first companies to offer HomePlug AV adapters. Product manager Alex Wei says the Zyxel PLA-400 will have a suggested retail price of US$99.
Zyxel is also working on a HomePlug AV adapter targeting telephone companies that are gearing up to compete with cable and satellite TV providers. The concept adapter at Zyxel's booth supported both ethernet and coaxial cable, with a small switch to toggle between the two. The idea is that you'd be able to stream incoming video from its point of entry (wherever your phone line comes in) to a HomePlug AV adapter connected to a TV's coaxial input port.
Wei says that in his own informal tests transferring files via FTP, he saw throughput of up to 90 mbps with the HomePlug ethernet adapter.
HomePlug AV is not the only power-line technology -- in fact, it's the third of three competing technologies promising similar speed, all over existing electrical wires. Panasonic introduced its HD-PLC power-line adapters earlier this year, and Netgear has recently introduced Powerline HD adapters based on the Universal Powerline Association's Digital Home Standard technology from a Spanish company called DS2.
But while HomePlug AV may be late to the power-line party -- it was announced in October 2002 -- neither of its competitors (both of which started out as candidates to become the next-generation HomePlug standard) appear to have as much backing. The HomePlug Powerline Alliance's membership roster includes such high-profile companies as EarthLink, Intel, Linksys (which had prototype products at the HomePlug conference and has promised commercial products by year's end), Motorola, Samsung, and Sony.
The HomePlug Powerline Alliance's conference documents included descriptions of coming HomePlug AV adapters from ActionTec, Delta Electronics, and GigaFast. But the biggest display of products was in the booth of Intellon, a principal contributor to the technology.
Optimized for video
Presentations at the conference focused on applications that can best benefit from HomePlug AV, almost all of which involved some kind of multimedia streaming: distributing IPTV throughout the home, monitoring for security with video cameras, and networked set-top boxes such as TiVo or Sling Media's SlingBox. In fact, power-line networking is nothing new for some existing SlingBox owners: Sling Media's SlingLinks power-line adapters, accessories that connect SlingBoxes to network routers in homes that do not have ethernet cabling, are based on the original 14-mbps HomePlug 1.0 standard.
Intellon has claimed that HomePlug AV's technology is superior to its power-line competitors in part because it is better able to handle circuit noise resulting from the presence or introduction of other electrical devices on the same circuit as the networked devices.
A demonstration at the Intellon booth sought to prove the claim. It consisted of side-by-side notebooks displaying a couple of video streams, which Intellon said were being transmitted from another notebook over a HomePlug AV network on one system, and either a DS2 or Panasonic HD-PLC network on the other.
The video streams looked great on both displays -- until a lamp was plugged into the same power strip. The HomePlug AV video played on uninterrupted, but artifacts appeared on the display showing video streamed over the competing technologies.