HomePlug Networks Plug In and Power Up

First shipping power-line USB adapters offer good speeds, strong security.

Matt Lake

Preliminary tests of early HomePlug networking products prompted us to give them a cautiously optimistic endorsement in our April issue, despite the dubious history of power-line technology. Now units are coming to market, and despite a few quirks this first batch of shipping USB products clearly represents a viable alternative to today's wireless networks.

We tested three vendors' products: GigaFast's PE901-UI, Linksys's PLUSB10, and Netgear's XA601. The results were good--and shockingly similar. Whether we used a single vendor's adapters or mixed units from several companies, the outcome was essentially the same: a serviceable and easy-to-configure network.

Security is another plus. While vendors of wireless networks continue to struggle with some thorny issues in this area, all producers of HomePlug adapters use 56-bit DES encryption, where the encryption key password is stored within the devices.

Our test environment was not favorable to power-line networking. Our three networks spanned all levels of a four-story house constructed in the 1920s; and we ran our tests during the dog days of summer, when the area's electrical supply suffers the greatest number of brownouts, spikes, and surges. If HomePlug could perform effectively there, we figured, it could do the job practically anywhere.

Separable but Equal

All three of the USB adapters we looked at moved data more slowly than the HomePlug standard's rated top speed of 14 megabits per second; in our test house, each of the adapters averaged a transfer rate of about 5 mbps. Even so, that rate is significantly higher than the 1.5-mbps top speed most broadband Internet connections can manage--and that makes a HomePlug network ideal for sharing access to the Web and e-mail servers. It's also a good choice for sharing printers and occasionally swapping files (though you'll feel the pinch if you regularly swap 10MB-plus folders).

We observed some slight differences in data transfer speeds. On average, the GigaFast and Netgear adapters moved data about 8 percent faster than the Linksys did during our speed trials. But those averages conceal the actual story: Each adapter performed at widely varying rates at different times, presumably because of the unpredictable nature of the power supply.

The GigaFast PE901-UI is smaller than the other two products--about the width and length of a floppy disk--and it comes with a three-year warranty. The placement of its USB and power sockets, however, isn't terribly convenient. The USB socket is situated on the front, next to the indicator lights, and the power plug lies in the back; to view the indicator lights, you must tolerate having the USB cable strewn across your desk.

Linksys's PLUSB10 adapter ($99) is the bulkiest of the three (approximately the size of a hardcover book). Its power and USB sockets reside at opposite ends, which makes stretching the distance between socket and PC easier. The design doesn't improve cable management, however. And the unit has a puny one-year warranty (versus the three years offered by its two competitors).

Netgear's slim, sliver-tone XA601 adapter ($120) is approximately the size of a mass-market paperback. We liked the unit's socket placement best of the three, with power and USB cables plugged into the back, allowing for easy and tidy cable management. It comes with a wall-mounting kit and a desktop stand, so you can place it vertically next to the PC. The unit has a three-year warranty.

Each of these adapters gets a thumbs-up, but with reservations. Since some surge protectors and universal power supplies treat the network signals as power surges and strip them out, you need a clear path between the adapters and the wall plugs for best results.

Because all three adapters use the same Intellon chip set, they share the same limitations. In theory you can connect up to 16 computers on a HomePlug network, but in practice that number drops to just 3 unless you run system-intensive background software on each computer.

USB adapters have a physical limitation, too: You can't plug them directly into an ethernet hub or router. To share ethernet-based broadband, you have to jump through some needless hoops--such as plugging an ethernet HomePlug adapter into a broadband router.

The main appeal of HomePlug power-line adapters is that they're easier to install in a home than ethernet or phone-line HomePNA networks (the former necessitates running cables, and the latter entails placing all PCs near a phone jack). HomePlug adapters are faster than most wireless networks, too, and they don't suffer the signal degradation between floors that Wi-Fi does. On the other hand, HomePlug products are slightly more expensive in general.

Although no clear winner surfaced among our three test units, two of them will satisfy particular needs. The Netgear adapter--the sleekest of the bunch--offers the best cable and mounting options, and the comparable-performing GigaFast is the smallest. Both offer generous warranties.

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