Back in the Stone Age of home networking, anyone who wanted to play on a computer not hooked directly into an Internet connection had to snake phone lines or Ethernet wires across floors and up staircases.
People talked about a promising idea: using the electrical wiring already in the house to move data from room to room. One early application, the X10 system for controlling lights and appliances, didn't always work well. The technology was certainly not ready to be used to bring Web pages to computers anywhere in the house.
Along came the wireless network. For $50, you could get the Internet sprayed across the house and never be tethered by a cord to the wall. It was slow in those early days, notoriously unreliable, and open to interception if you couldn't bother with setting up the encryption codes.
But it caught on. According to estimates made by Parks Associates, a market research firm based in Dallas, about 12.5 million homes now have wireless networks; another 10 million homes, mostly newer ones, have Ethernet or coaxial cables in the walls.
Cheap and ubiquitous is a hard combination to beat. But wireless networks did not end the quest to put data through electrical wires.
Technology companies continued to work on the idea. Some tried using phone circuits. A version for power lines called HomePlug came out in 2002, and while it hardly affected sales of wireless network equipment, it sold enough that major companies like Intel, Cisco, Sony, Sharp and Comcast created the HomePlug Alliance to push for next-generation products, with the first to come out later this year.
"I don't think anyone had expected the technology to progress," said Andy Melder, senior vice president for sales, marketing and business development at the Intellon Corporation, a maker of chips for home networking devices that use power lines.
Some companies are not waiting. Panasonic, Netgear and Marantz are already offering products that will move data through home electrical lines faster than routers using the current Wi-Fi standard for wireless networking, 802.11g.
Panasonic started selling its HD-PLC Ethernet adapters for power lines last month. A $200 starter kit provides two units, each about the size of two sticks of butter.
One adapter is attached to a router with a short Ethernet cable and plugged into a nearby wall outlet. The second device is plugged into an outlet elsewhere in the house. When a computer is linked to it with an Ethernet cable, data is transmitted through the home's electrical wiring at speeds of up to 190 megabits a second. Up to seven devices can run on the network.
Netgear, a leading maker of wireless networking gear, will be selling a similar system next month for about $300. (Every additional module costs about $150.) It moves data at a slightly faster rate.
Marantz says its ZR6001SP receiver will send music to special speakers in another room over power lines. The system, which includes both devices, will sell for about $1,300. Additional speaker units cost about $300. The music listener controls the receiver and the CD players or iPods connected to it from a control pad on the speakers.
"We were getting many requests from installers, like how do I get multiroom audio if I can't run wires," said Kevin Zarow, vice president for marketing and product development. The Marantz device also solves the problem of running speaker wires across a room.
At first blush, these products may seem to be nonstarters. After all, who would want to pay two or three times the price of a wireless network?
The answer lies in the simplicity.
Robert Stephens, founder and "chief inspector" of the Geek Squad installation and troubleshooting division at Best Buy, said installing wireless networks was the leading reason for house calls. "It's why most people need us," he said, noting that the complexity of installing a wireless network is evident from the fact that return rates on wireless networking devices drop to nearly zero when his installers do the work.
The Panasonic network over power lines, on the other hand, was up and running in less than five minutes. Encryption was automatically enabled, and there was no need to configure anything. It worked well even in a house with 90-year-old cloth-wrapped tube-and-knob wiring where the lights sometimes flicker. And though Panasonic warns that operating a power drill or a vacuum cleaner on the same outlet may cause an interruption of Internet service, running both while using the HD-PLC on the old wiring did not pose a problem.
The makers of all three products said that people who cannot get whole-house coverage with a wireless system or those plagued by dead zones might find it appealing.
But the real selling point for the technology is that it can transmit high-definition video without pixelating or skipping. It can claim that advantage over wireless networks — at least for now — because it has a higher data transmission rate.
"Three years ago, the majority of devices connected to a home network were home computers," said Mike Timar, national marketing manager for Panasonic's communications and home office electronics division. "But today there are MP3 players, game consoles and high-definition TV."
Wireless routers using the 802.11g standard move data at 54 megabits a second. That's fine for Web pages, but too constrained to move a high-definition video image, which needs about 85 megabits of capacity. The Panasonic and Netgear products have more than enough room to handle that, as will the HomePlug devices coming out later this year.
The next-generation wireless routers, using the 802.11n standard, will also transmit about 200 megabits a second, but a network may initially cost $150 to $250, erasing the cost advantage that wireless now holds.
Pitching the device to the next generation of TV watchers with high-definition televisions and DVD players also pulls in the market for game console users who might want to run multiplayer games from multiple rooms. It also neatly sidesteps the argument that wireless is more convenient.
"If you are watching TV, you don't care about mobility," said Kartik Gada, Netgear's networking product line manager.
There is a hitch, however. The three companies' products are not compatible with one another. Nor are they compatible with the products adhering to the standards set in August by the HomePlug Alliance.
Netgear and Panasonic jumped the gun on the standard out of frustration with what they said was the slow pace of the alliance. (Marantz is using a system called DAvED, which stands for digital audio via electrical distribution.)
"Not going with a standard-based approach is problematic," said Mr. Melder of Intellon, who is also a spokesman for the HomePlug Alliance. "It tends to freeze the consumer."
Panasonic executives said the company's breaking of the ranks would not necessarily create compatibility problems in the long run. They said a second standards group, the Consumer Electronics Powerline Communication Alliance, is working to ensure that all the networking devices for power lines could coexist and communicate.
There is something that all the makers of such gear, including Netgear and Cisco's Linksys unit, can agree on. People will probably end up having both wireless and wired connections in their homes.
Within about 18 months, cable companies may start offering set-top boxes with networking abilities over power lines. Computer makers, as well as television and DVD makers, will do the same. At that point, all a consumer will have to do is stick the power plug into the wall and the data will come racing down the wires with the electricity.