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

Power-line devices can use existing electrical wiring to connect you to your router -- and therefore to the Internet. But what kind of performance will you get?

By Bill O'Brien

Computerworld |

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How we tested

My current configuration is wireless and uses a pair of Netgear WNHDE111 5-GHz wireless adapters as an access point (upstairs) and a bridge (downstairs). For testing purposes, I also used a Linksys WRT600n Dual-Band Wireless-N Gigabit Router and a Linksys EG008W Gigabit 8-Port Workgroup Switch.

I decided to test the power-line devices and the 802.11n and wired networks starting with a clean file transfer of 4,661 files and folders (8.05GB) from a computer downstairs to a computer upstairs. Nothing else would be happening on the network while this transfer was in progress. Then, I repeated that file transfer five more times, each time adding a video stream from a MicroNet MaxNAS RAID with SCSI, which I was using as a media server upstairs, to one of five additional PCs downstairs. That indicated how well each method handled file transfers under load and no-load conditions.

As expected, wired was the fastest across all testing. The clean file transfer needed a meager 6.6 minutes to complete, and that time varied by only an infinitesimal 0.05 minutes for all iterations of streaming video.

Wireless was a bit slower and a bit more varied. It took almost 15 minutes to complete the clean file transfer to the upstairs computer. Each time a video stream was added to the network, that number climbed slightly until it finally reached 16 minutes and 50 seconds when five videos were playing simultaneously. On average, each video stream added about a third of a minute to the final time. The streaming quality of the videos remained the same whether it was one or five playing simultaneously.

In testing the power-line devices, I started with a room-to-room test where I plugged one of the modules into a relatively new (five-year-old) electrical outlet downstairs and the other module into one of the house's original (over 40-year-old) electrical outlets upstairs. In theory, this is the typical home scenario -- for that reason, no attempt was made to discover if the two outlets were or weren't on the same phase leg, since it is unlikely that the typical home owner would know.

I also set up the power-line equipment using a 90-foot extension cord into which one of the modules was connected downstairs; that extension cord was then plugged into the same outlet upstairs as the second module. Basically, this represented a connection through a length of electrical wire in which there were no phase leg, aging or wire condition problems. In a new home, or if you had an electrician run two outlets from your breaker box, you would probably find transmission times similar to these. (This was the setup I used when testing the power-line devices with video streams.)

Finally, I plugged the two modules into the same outlet. In theory, with little to no electrical wire between them, this would be the fastest they could communicate with each other under any network load condition, offering performance under what would pass for ideal conditions.

Don't want Power-line? HOw to wire -- carefully.

If you're dead set on running wires between the floors or walls of your home, I sincerely recommend that you hire a professional to do the work. Minor intervening items like heating, ventilation and air conditioning ducts and electrical wiring are not only expensive to repair or replace, but a drill bit inadvertently striking a live electrical line can damage a building beyond repair. Also, aside from the safety aspect, having a third party perform the work shifts liability from you to them.

I lucked out, sort of. A few years ago, the local cable TV company added a line for a television at a new location in the living room and tore down some ceiling tiles in the basement to route the cable up from below. One of the missing ceiling tiles is directly above my downstairs network switch, which, by luck, is directly below the upstairs router. With the tile gone, I could see the area I needed to drill and verified that there were no obstructions.

Because a missing ceiling tile was directly above his downstairs network switch -- and directly below the upstairs router -- O'Brien could see the area he needed to drill and verify that there were no obstructions.

Even so, I used a thin and long drill bit to create an unobtrusive pilot hole, covered it with a lighted flashlight so I could see the location of the hole from below through the darkness of the ceiling, and only then, when I'd verified that everything was where it should be, proceeded to drill the full-width hole. (If you're going to do what I did and use a prewired cable, you may have to "route" that hole out a bit with some drill jiggling to get the connector to fit through.)

Once the cable was accessible, that was it. I just connected it to the downstairs switch and the upstairs router. As all of my computers, switches and routers have 1 Gigabit LAN ports, the immediate benefit would naturally be a tenfold improvement over the 100Mbit/sec. speed available from the wireless setup. All right, maybe not a tenfold pickup, but I was curious to see whether whatever any improvement was worth the angst and possible repercussions of drilling a hole through the living room floor.

Bottom line: It was worth it.

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