Wireless LANs (WLANs) may get most of the marketing hype, but they're not the only way of linking computers in different parts of your home or office. With commercial broadband over powerline (BPL) trials now up and running in several states, the idea of using existing electrical wiring is becoming more and more relevant.
It's not the first time BPL technology has been available, but earlier solutions for home networking lost out to competing WLAN solutions that gained the mindshare and enjoyed rapid speed improvements. With its PowerLine 85 Ethernet Adapter (PL85), however, AdvaTel has aimed to resurrect the concept of easy-as-pie home and office networking - and succeeds marvellously.
Each PL85 unit is about the same size as a traditional AC adapter you'd get with any consumer electronics product. The sturdy, translucent black plastic case gives a hint of the circuitry inside, with three indicator lights on the unit's front confirming the presence of power, the availability of a powerline network on the current premises, and successful network connectivity. A series of vent holes on the unit's top allows heat to escape, with connectivity through a single RJ-45 network socket on the unit's bottom.
Our only complaint with the unit is its width: when trying to plug the unit into a 2-out power point, we found the physical width of the PL85 could crowd out some other types of plugs, forcing us to unplug the other devices. Buying a power strip with wider-spaced power points is one option, but we recommend that AdvaTel think a little bit slimmer in its next redesign.
Features aren't the strong point of the PL85, but they're not supposed to be, either: this is one case where simplicity truly is better.
To appease those understandably concerned about plugging a 240V source directly into their computers, AdvaTel has built a surge protector into the unit. The PL85 units are compatible with HomePlug 1 (a 14Mbps home networking standard developed in 2000) and IEEE 802.3 (the wired Ethernet standard), offering a claimed speed of up to 85Mbps. Ethernet cables are included in the pack.
PL85s also include 56-bit DES encryption, ensuring data on your network stays there; this encryption is enabled using a manufacturer-set public network key by default, but this key can be changed using the bundled PowerLine 85 Utility. That utility also provides auto-detection of installed units and the ability to give each device a permanent name so you don't get them confused.
AdvaTel says up to 255 units can be added to a home network; however, because the method for transmitting data is limited by the available bandwidth in a specific frequency range, bandwidth is shared and performance per node will decrease in heavy usage situations. In an average house, the company claims around 10 units can be installed without affecting performance; this should be more than ample for most people. Since numerous computers can also be connected to the PL85 via a small network switch, the devices could easily be used to wire up a large number of office desktops.
For a device like this, usability and performance are far more important than looks and features, and the PL85s didn't disappoint. After removing the PL85s from the two-pack we evaluated, we plugged the units in and, within two minutes, had established an Ethernet connection between the home office and a bedroom halfway across the house. Because the PL85s function at OSI Layer 2 (as does Ethernet), there's no configuration required; they act transparently as extensions to the existing Ethernet network.
Configuration utility screen shot Click to enlarge.
For testing, we plugged one unit into an empty home-office power point, then plugged the Ethernet cable into a free port on our existing Netgear WGR614 wireless router. We then plugged our test notebook into the second unit at various power points around the house, testing both self-reported speeds (through the PowerLine 85 Utility software) and real-world Internet performance.
We also used the analysis mode of the PerfPing freeware application to test LAN performance; this mode tests network performance by timing transmission of seven files of predefined sizes between the remote PL85 unit and an IP node (in this case, a desktop PC connected by fixed Ethernet cabling to the same WGR614 as the PL85 was connected to). In each case, we ran the same tests using the built-in WLAN connectivity of our test notebook.
Performance tests confirmed that the PL85s are indeed capable of pushing data through the house at speeds that were generally faster than WLAN. For example, in the front bedroom, on the opposite side of the house, several runs of the CNET Bandwidth Meter reported an average transmission speed of 389.6 kbps over the power lines, compared with 214.1 kbps via wireless in the same location. In that room, PerfPing's 64KB block test completed in less than half the time via the PL85s as over wireless, with 10-byte pings of 16ms over wireless far longer than the 3ms over the power lines. Small-packet ping times, which varied widely over the WLAN, were consistently gauged at 3ms to 4ms - suggesting the PL85s are much more appropriate for latency-sensitive applications like network gaming.
Because the PL85's performance depends on the house's electrical wiring, we measured performance at power points located near two common sources of electrical noise: a fan-powered gas heater in the lounge room, and the refrigerator in the kitchen. Near the gas heater, the PL85's performance was much more similar to that of the WLAN (239.3 kbps vs 208.3 kbps), but the 64KB ping test still only took half as long over the powerlines. Near the refrigerator, the gap was even smaller (213.0 kbps vs 204.3 kbps) but pinging was still generally faster over the PL85s - and the units completed the 50KB and 64KB tests even when the WLAN configuration timed out.Note: DNC = Did not complete / timeout
Perhaps most interesting was the finding that the PL85s could deliver equally fast broadband to the spare room in the separate rear garage. Because it lies through two brick walls, WLAN signals have traditionally struggled to reach that room - but plugging in the PL85 unit gave healthy ping times and average Internet access speed of 224.9 kbps.
Our testing suggests the PL85s are an ideal solution for everyday home networking, particularly in configurations such as linking a lounge-room PC with a desktop PC for smooth delivery of networked video. Because the PL85 operates as a transparent Layer 2 device, it also offers an inexpensive way of linking game consoles, VoIP phones and other devices with their Internet connections. In buildings where WLAN coverage is less than optimal or simply unavailable, the PL85 is an excellent alternative that provides more consistent and predictable network access to places that couldn't previously get it.
A 2-unit starter pack is AU$225.50 with additional units priced at AU$137.50; a six-pack is also available for AU$644.60.
|PerfPing Analysis (milliseconds, lower is better)|
|Location||Self-reported speed (Mbps)||Avg. CNET |
|10 bytes||100 bytes||500 bytes||1KB||10KB||50KB||64KB|
|Next to desktop (PL85)||80.60||374.5||<1< td="">||<1< td="">||<1< td="">||<1< td="">||5||28||36|
|Next to desktop (WLAN)||--||--||2||2||2||5||59||114||DNC|
|Front bedroom (PL85)||45.89||389.6||3||4||7||23||173||494||530|
|Front bedroom (WLAN)||--||214.1||16||31||35||14||76||470||1237|
|Near gas heater (PL85)||47.53||239.3||4||4||9||28||66||370||443|
|Near gas heater (WLAN)||--||208.3||3||1||3||6||101||394||773|
|Behind main TV unit (PL85)||85||332.8||3||3||4||8||56||197||248|
|Behind main TV unit (WLAN)||--||211.5||1||3||4||10||57||282||DNC|
|Next to fridge (PL85)||21.71||213.0||3||5||12||47||110||593||756|
|Next to fridge (WLAN)||--||204.3||2||4||4||83||267||DNC||DNC|