Review: 5 power-line devices that take you online where Ethernet or Wi-Fi can't

Computerworld - When your router/modem is "here" and you have one or more computers either upstairs or downstairs from that location -- or both! -- life begins to get complex. Hardwiring your network is fast and efficient, but it's often not a practical answer, especially for homes and small offices. Renters may have difficulty convincing their landlords to let them rewire a home or apartment that they don't own themselves. Even wiring your own place may not be fiscally feasible.

Most people who can't or won't hardwire for broadband have an obvious alternative: Wi-Fi. Unfortunately, there can be architectural anomalies between floors or even between rooms that can interfere with Wi-Fi signals, resulting in spotty, or even dead, signals. So what do you do?

Well, you can try using a power-line device.

Power-line networking uses existing electrical wiring to connect your computers and other devices to your network router. The technology behind it allows for multiple signals (and therefore several networked devices) to share the same wires that already exist in your walls without colliding with one another while they're communicating.

Unfortunately, power-line networking has never really caught on as well as it should. It began life at 14Mbit/sec. in 2001 and then bumped up to 100Mbit/sec. in 2005 when hardwire and Wi-Fi were still at 10/100Mbit/sec. and 57Mbit/sec., respectively. Power-line reached a claimed 200Mbit/sec. in 2007, which should be more than enough for our data and streaming-media needs.

There are still a few hitches. Here in the U.S., we tend to run split-phase wiring. The electrical service enters our homes as 240 volts made up of two 120V lines (or legs). Our 120V outlets are derived from tapping off one or the other of those 120V legs. As a result, you may not be able to network devices that are plugged into outlets on different legs. In addition, older wiring and long wire runs can slow down power-line transmission speeds.

We decided to test five power-line devices from Belkin, D-Link, Linksys, Netgear and Zyxel to see both how they compared with more conventional wired and wireless setups and how they compared with one another. (See "How we tested" for details.)

The results? It's obvious that power-line devices rank third in broadband performance. But for those who can't hardwire their homes or for whom wireless networking is less than useful, power-line could be a saving grace.

Which power-line device should you use? Check out the following reviews for some help in making your choice.

Power-line test results