The GHPU01 is a svelte little unit in a gun-metal grey case with indicator lights for power, link, activity, and even collisions. Aside from that, there's a USB port on the front and an AC power connector on the back.

The $99 IOGEAR GHPU01 is based on the HomePlug 1.0 standard, which allows your home's electrical lines to transmit data up to 990 feet and provides 14 Mbps of bandwidth. On the other hand, because the GHPU01 is a USB 1.1 device, its inherent bandwidth is limited to 12 Mbps. It doesn't much matter though, because as with just about any other networking technology the actual throughput falls well short of the theoretical maximum. (Still, USB 2.0 support would be nice.)

Pros

• Easy to set up
• Better performance than 2.4GHz WLAN

Cons

• USB 1.1 interface caps performance

According to IOGEAR, the basic rule of thumb to calculate throughput of a HomePlug device is throughput =bandwidth/2. Given this formula, we expected to squeeze 6 Mb throughput out of this USB adapter (read on to see if we did) and closer to 7 Mb if using the GHPB01, which is a sister product that eschews USB in favor of an Ethernet interface (technically, it's a bridge).

The IOGEAR GHPU01 works with most versions of Windows, but it's not compatible with Windows 95, NT or the MacOS-- you'll need the GHPB01 for those systems. (Note: the unit's software is currently incompatible with Windows 9x systems using the Microsoft Virtual Private Networking adapter. A fix is planned for the future.)

IOGEAR recommends that you don't plug the GHPB01 into a power strip or surge suppressor that does power filtering. Having an electrical device plugged directly into my computer without protection against surges makes me a bit nervous, but IOGEAR says that the GHPU01 contains built-in suppression circuitry, and will take the bullet for your computer in the event of a surge. I'll buy that, but if you wanted to be extra cautious, plugging into a surge suppressor doesn't necessarily preclude the unit from working.

Installation

Installing and configuring the GHPU01 was a little idiosyncratic, but not difficult. For some reason, the driver CD doesn't automatically invoke the setup routine, so you have to run it manually. Once I did, it was pretty much smooth sailing--there aren't any variables to configure aside from the (mandatory) password.

Indeed, the installation was so boring that I might have nodded off had it not been for a fairly draconian license agreement I had to acknowledge before the installation would proceed. Rather than presenting the customary 93 pages of legalese, IOGEAR proffers a brief "User Contract," which among other things stipulates that the company is not responsible for damage to any user devices or software or for any "security threats."

Whatever. Maybe all end-user license agreements say the same thing in a less straightforward way; in any event, caveat emptor.

After the software is installed, you plug the GHPU01 into a USB port, reboot the system, and run the IOGEAR configuration utility.

The utility will display the MAC addresses of other HomePlug devices on your network that have been configured with the same password. Once this physical layer of connectivity is established, you can configure the associated IP settings as you wish.

Security

Security on the GHPU01 is basic and straightforward. The unit provides one level of encryption: 56-bit DES, which is invoked via an alphanumeric password of between 4 and 24 characters.

Thankfully, you have to specify a common password in order to set up a network with another machine. That's good news, because evidently the powerline network can extend into your neighbors' homes if you happen to be sharing a power transformer.

Do yourself a favor and configure as long and complex a password as you can stand, especially if you believe your neighbors to be untrustworthy (and technically inclined). Your dog's name will simply not do here -- if for no other reason than your neighbors are likely to know it.

Performance

For performance tests, I networked two notebooks with GHPU01 units (running Windows XP Home and Windows 2000 Professional) that were three rooms and about 50 feet apart. Following manufacturers recommendations, I plugged the GHPU01 devices directly into the wall rather than into a surge suppressor. The notebooks were each on separate electrical circuits, in a 25-year-old home.

The average throughput between systems was slightly north of 5Mbps, about 15% better than a typical 802.11b-based wireless LAN. At 375 Kbps, streaming performance was about on par with a wireless setup which isn't really isn't adequate for the majority of media types.

Clearly, this is not knock-your-socks-off speed. Still, it's quite good considering there was a time not long ago when powerline-based networking wasn't fast enough to deliver the information printed on a matchbook in a timely fashion. Use of the Ethernet-based GHPB01 (which is the same price) might afford a bit higher performance.

As mentioned earlier, plugging the unit into a surge suppressor will dull your performance slightly. My experience indicated it will shave about 10% off the top, as well as have a tendency to make your speed fluctuate as the suppressor potentially interferes with the power frequencies carrying the data.

Summary

The utility of a HomePlug-based networking product like the GHPU01 might seem questionable with the advent of things like wireless bridges and powerful directional antennas in the WLAN world. On the other hand, the IOGEAR GHPU01 is inexpensive, reasonably fast, and you can install it in your sleep, so it is a great way to network that PC in the upstairs corner bedroom where wiring isn't an option and the WLAN signal is weak.