Juicing Up Home Networks

The wiring behind your walls could connect the video in all your rooms


In the home of the not-too-distant future, video will zip from room to room. You'll be watching movies downloaded from the Internet in your bedroom and cable TV on your PC. Of course, the high-speed network needed to make this latest vision of the "connected home" function doesn't quite exist yet—but it may be hiding in your walls.

The simplest way to move data quickly is through the modified phone wiring known as Cat5 cable, the standard Ethernet network cable. The problem is that few homes, even new ones, are wired, and while Cat5 cable costs little to install in new construction, it is expensive to pull through existing walls.

Most people get around the lack of cables using wireless. But the current generation of Wi-Fi is not fast enough to deliver quality video reliably. A new version, called 802.11n, is starting to appear, and Apple (AAPL ) is counting on it to deliver video from iTunes on PCs to TVs via its Apple TV adapter. I'll be testing Apple TV when it's available, but I'm frankly dubious about the wireless part. There are just too many things in a home, from microwave ovens to people moving about, that can create interference and spoil the viewing experience.

A GOOD ALTERNATIVE MAY EXIST in the power wiring that already runs through your house. The idea of carrying data over electrical wires has been around for a long time, but early versions were slow and prone to interference, especially the electrical noise generated when appliance or air-conditioning motors start up. A new generation of powerline networking not only overcomes these difficulties but offers speeds at least as fast as the newest Wi-Fi. And the latest products are not subject to the seemingly random fluctuations in performance that afflict wireless.

I tested three different systems. A prototype from Zyxel Communications uses a new standard called HomePlug AV. The others, the NetGear (NTGR ) HDX101 (about $170 for the two units you'll need) and the Panasonic (MC ) HD-PLC (about $200 a pair), use a rival approach called Powerline HD.

Setting up powerline networking is simplicity itself. You plug an adapter into a power outlet and connect it to any port in your router with a standard Ethernet cable. Then you plug in additional adapters in any room where you need network service and connect a PC with another cable. As long as the hidden wires feeding the outlets are connected to each other somewhere, usually at the circuit breaker box, networking should work.

Both flavors of powerline networking claim speeds of up to 200 megabits per second, but as is the case with all networking technologies, you can only expect to see a small fraction of that theoretical maximum when moving real data. With the powerline products, I got average speeds of 12 to 20 megabits per second when moving large files between PCs. That's a bit faster than what I recorded on a Wi-Fi network with a rated speed of 54 megabits per second, but only about half the speed I got using cabled Ethernet.

The problem with video is that average speed doesn't tell you much. A brief interruption won't really affect the average speed, but it will likely cause the picture to freeze temporarily and may also produce a hiccup in sound. I found that the powerline systems did a fine job of delivering broadcast-quality TV and could handle DVD quality with only an occasional glitch. High-definition TV was rougher: The picture froze repeatedly, and the sound started and stopped. For HD, we may have to wait for an approach called MoCA (for the sponsoring Multimedia over Coax Alliance), which sends data over the wires used by cable TV.

Powerline networking is more expensive and less convenient than Wi-Fi. But it can deliver data faster and more reliably than wireless. It may be what's required to take us to the next stage of networked entertainment.

For past columns and online-only reviews, go to Technology & You at businessweek.com/go/techmaven/

By Stephen H. Wildstrom

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