HomePlug network adapters — which extend a home network by using regular AC power lines to transmit data — can be a good choice for networking a far-flung computer or other device when going wireless is not an option (perhaps due to interference or excessive distance). With performance rated at 14 Mbps (and real-world throughput of roughly half that) it’s more than adequate for sharing an Internet connection or basic browsing and e-mail, but much less appropriate for bandwidth-intensive tasks like streaming media or moving large video or audio files around the home.

SMC’s new $89.95 EZ Connect 85 Mbps Turbo Powerline to Ethernet Desktop Adapter (SMCHT-ETH) aims to address this weakness, as it’s based on the newest HomePlug specification, dubbed “1.0 with Turbo.” With a quoted speed of 85 Mbps, it boasts more than a sixfold increase in performance over the previous spec. Although the networking device that lives up to its performance claims has yet to be invented, we were indeed disappointed by the SMCHT-ETH’s performance, not only relative to the speed claims, but also to prior-generation HomePlug products.

Unlike some Powerline adapters, SMC’s adapter isn’t a bulky wall-wart design that plugs directly into an outlet. Instead it comes in a compact desktop form factor (¾ x 4 ¼ x 2 ¾, HWD) that connects to AC using a “shaver” power cord. We can see the benefits to this approach, since it can enable easier physical access than something plugged in behind or under a heavy piece of furniture. The thin AC power cord also won’t block access to other outlets on a crowded power strip where space is at a premium. (It’s strongly recommended that you not plug the SMCHT-ETH or any HomePlug device into a surge suppressor or UPS [define] since they can interfere with or prevent connection.)

The device isn’t very heavy but it has rubber feet that should keep it in place as long as there’s enough slack in the Ethernet and power cables connected to it. A trio of status lights on the SMCHT-ETH front panel indicates power, an Ethernet connection, and the presence of any additional HomePlug devices.

Using the SMCHT-ETH to get an Ethernet device onto an existing LAN proved to be a pretty simple task. (Since routers with HomePlug capability are relatively rare, most users will need a pair of adapters to integrate one device with a network.)

We started by plugging an SMCHT-ETH into AC power and connecting it to a LAN port on our router. A subsequent check of the router’s DHCP [define] settings showed that the SMCHT-ETH had been issued an IP address. The next step was to connect another SMCHT-ETH to the computer we wanted to add to the LAN. Upon doing so (and enabling the system’s dormant Ethernet connection in Windows), it too had obtained an IP address and was able to communicate with the LAN and through to the Internet.

Since drivers aren’t required for a device that connects to an Ethernet port, it’s not necessary to install any software in order to use the SMCHT-ETH. This means the SMCHT-ETH should work equally well with Windows, Mac and Linux PCs. However, you’ll still want to install SMC’s PowerPacket utility (which works only with Windows) because it lets you check the status of the adapters on your network and the connection strength between them.

Another reason to use the PowerPacket utility is that it’s required in order to enable the SMCHT-ETH’s encryption feature. Enabling encryption is important because just like with wireless networking, information transmitted via powerline can potentially leave the confines of the home. Indeed, the data signal carried along your home’s electrical wiring can traverse circuit breakers and thus be accessed via outlets in any adjacent buildings that share the same AC transformer. (The signal cannot, however, travel beyond the transformer).

The SMCHT-ETH uses 56-bit DES encryption to secure its data transmissions, and each unit comes with a unique 16-character alphabetic password (found on the underside of the unit) that must be entered in order to enable encryption on the unit. Encryption is set up simply by using PowerPacket to create a private group of HomePlug devices with a common network group name. The private group is then made invisible by any HomePlug adapter that’s not a member of the group.

To gauge the performance of the SMCHT-ETH we used a pair of adapters and connected each directly to a Windows XP PC (a desktop and a notebook). We then moved the notebook from room to room and in each used Ixia’s Qcheck utility to measure the throughput between the two systems.

Although we did not anticipate throughput remotely approaching the quoted 85 Mbps figure and we did expect that throughput would vary somewhat between different AC outlets, we were surprised by how low the test scores were overall. In fact, in most cases they were only marginally better than the 4-6 Mbps you’d typically get from an older 14 Mbps HomePlug device.

For example, Qcheck reported throughput of between 11 and 12 Mbps between a home office and a kitchen about 50 feet away. In the adjacent dining room, which was physically closer to the office, throughput dropped essentially in half, to between 5 and 7 Mbps. On the other hand, moving even further away from the office into a back bedroom improved throughput somewhat, to between 8 and 9 Mbps. Connecting both SMCHT-ETH units to the same wall outlet yielded the best performance — between 24 and 26 Mbps. Even in this essentially useless scenario the throughput was only about as much as you would see from conventional 802.11g hardware.

The Bottom Line
The performance of the SMCHT-ETH was indeed disappointing. Although HomePlug adapters are known to be sensitive to the age of a home (or more to the point, of its electrical wiring), it’s worth noting that these tests were conducted in a relatively small and nearly new home (approximately 1,600 square feet and built in 2002). We didn’t have the opportunity to compare the SMCHT-ETH’s performance to that of any other vendor’s HomePlug products, but given that all such devices use a common third-party chipset (from Intellon), it’s a reasonable bet that they would have performed as well (or in this case, as poorly) as those from SMC.

As long as performance is not your paramount concern, the SMCTH-ETH can is still be useful for networking device (especially a game system). That said, given the modest performance it’s hard to justify paying about $180 (the price of two adapters) to do so. On the one hand, that price is about the same price as SMC’s prior-generation HomePlug devices, and the new generation is unquestionably faster than the old. On the other hand, SMC products based on the earlier spec are still available and are now being sold at a discount (around $50-$60) and on a price/performance basis they’re arguably now a much better buy than the newer products.


Price: $89.99 (MSRP)

Pros: easy setup

Cons: disappointing performance; expensive


Joe Moran is a regular contributor to PracticallyNetworked.