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Powerline Pessimism

October 10, 2005

Powerline networking, for both LAN and WAN applications, is once again a hot topic after years' worth of periodic hype. Cisco's Linksys division, Intel and Motorola have joined the HomePlug Industry Alliance board of directors, and Intel and Motorola have both invested in dominant powerline networking silicon provider Intellon. The HomePlug AV standard, touting a 200 Mbps PHY rate, is finalized, and the HomePlug Conference 'lovefest' was held just two weeks ago.

Friday, at a digital audio networking panel held here at the Audio Engineering Society Conference, a Microsoft representative extolled the promise of HomePlug AV (along with 802.11e/n) as a means of easily and reliably distributing high bit-rate data streams around consumers' homes. The city of Manassas, Virginia just announced that powerline would be the means by which it distributed broadband Internet access to its citizens; so did the state of Tazmania in Australia, and Google's even investing in BPL (then again, what isn't Google investing in?). And, judging from the abundance of comments to Maury's ongoing blog post series, powerline networking is a topic that you're closely following, too.

Call me a wet blanket, if you want, but I feel compelled to inject some pragmatic hands-on perspective into the debate. Summertime arrived in Sacramento four months ago and, just as in years past, the HomePlug-based spurs of my LAN started flaking out again. Before you continue, please read (or re-read) my short article 'A Man, A LAN, a Plan' originally published last August; specifically, peruse the floorplan of my network's topology (link is to a PDF). And keep in mind that mine is a single-story home of less than 2,000 square foot size, built in the mid-1950s. Not some sprawling mansion with ancient, degraded wiring.

Throughout June, the powerline link between my office and our backyard 'hut' would be working fine when I got up in the morning, but by mid-afternoon the connection would be severed. By July, the office-to-hut link was dead 24 hours a day. And the link between my office and the AC (more accurately, evaporative cooler, commonly known as 'swamp cooler') closet got flaky every time the fan kicked on; pings to Yahoo's server that normally returned within 10 msec randomly stretched to a second or more, and occasional packets completely disappeared. The Cogency Connection Manager utility verified that whereas one half of the bidirectional office-to-closet link remained essentially solid, the opposing direction's data flow was severely compromised. And I saw the same problem with both Belkin and Maverick Power Systems v1.0 (14 Mbps) HomePlug hardware.

Last September, Intellon announced its first v1.0 Turbo (85 Mbps) HomePlug chipset and, when I met with the company at January's Consumer Electronics Show, they promised me a few v1.0 Turbo-based Ethernet-to-HomePlug adapters to test. In early June I received word that the adapters were nearing shipment, although it took two more months for the first two Aztech Turbo adapters to arrive (minus a configuration utility) and another month for the third (along with software) to show up. Fortunately, I was able to configure their passwords using the Cogency software (v1.0 and v1.0 Turbo adapters were also able to communicate with each other), although Connection Manager wasn't able to measure the data bandwidth running to and from the v1.0 Turbo units.

Good news: the v1.0 Turbo units didn't function any worse than their v1.0 predecessors. Bad news: they didn't function any better. Let me clarify that last statement; when the link was solid, the v1.0 Turbo bandwidth was approximately 30 Mbps, versus 7 Mbps with v1.0 units. But in any situation where a v1.0 device failed to establish or hold a reliable link to its peer, a v1.0 Turbo device would also fail. Also, I discovered that Aztech's units wouldn't interoperate with an old Kingston Technologies 10 Mbit hub I'd been successfully using with the v1.0 adapters; if I plugged a LAN client directly into the Aztech adapter, it'd establish network connectivity, but not if the hub was the intermediary. This was maddening to figure out; practically speaking, however, it was a non-issue. I'd already planned to replace the hub with a 100 Mbit switch, and the 802.11b access point in the hut with an 802.11g AP, reflective of the v1.0 Turbo HomePlug adapter's higher bandwidth capability.

Continued with 'Powerline Pessimism: Partial Progress and Pending Plans'….

Posted by Brian Dipert on October 10, 2005 | Comments (9)

June 2, 2010
In response to: Powerline Pessimism
urbarsese commented:

Damn!!! A Couple of days ago I got a call from 9722840600 - 972-284-0600 and was pretty sure the caller was a scam. I’m so sick and tired of promotional calls - I decided to complain to the gov and bitch. Check this out… Gulf Coast Western — the oil drilling company- contacted me We’re contacting me about employment. Apparently I got the job Wow, I really feel dumb. But I think I’ve lost my chance…???


June 2, 2010
In response to: Powerline Pessimism
urbarsese commented:

OMFG! This morning I received a message from 972-284-0600 & 9722840600 and I thought the the person calling was a scammer. So I decided to complain and dialed Gulf Coast Western and went nuts. You will never believe it… Gulf Coast Western -an oil corporation- was calling who I interviewed with last month - we’re calling to tell me I got the job! Any advice or help on how I can fix the complaint - and get the job?!!!


March 21, 2010
In response to: Powerline Pessimism
NonoIrrassy commented:

Check this Out! 3 hrs ago I received a phone message from 972-284-0600 and for some reason thought the call was a scammer. I'm so sick and tired of promotional calls - I decided to complain to the Gulf Coast Western and complain. You will never believe it... Gulf Coast Western -the oil drilling company- was calling We're contacting me about employment. Apparently I got the job How do I fix this??


March 16, 2010
In response to: Powerline Pessimism
Avampibia commented:

Todd Cowle Municipal Bond Credit Report synthesizes, analyzes and presents aggregate credit information and trends in the municipal bond market. The report includes municipal bond rating information from the three major rating agencies ? Moody?s Investor Services, Standard and Poor?s and Fitch Ratings.


February 12, 2010
In response to: Powerline Pessimism
Lagsexels commented:

Hi all, my friend told me about this forum so i decided to sign up. hopefully i can participate in some lively discussions here! looking forward to talking to you all. :)


January 21, 2010
In response to: Powerline Pessimism
pisiodsSisa commented:

Greatings , im new to this forum/blog thing. its a good place full of good info :)


September 18, 2009
In response to: Powerline Pessimism
XRumerTest commented:

Hello. And Bye.


October 13, 2005
In response to: Powerline Pessimism
RH commented:

A million years ago (it seems) I ran a series of tests of AC wiring in both residential and industrial buildings. A few things we learned may be of interest here. First, we too noted that the noise on the powerlines varied dramatically over time. Even in smaller locations we were never able to correlate this noise with any of the local "appliances". Second, and perhaps more interestingly, I seem to recall that we noted a fairly substantial change in both the characteristic impedance of outlets and the overall transfer function between them over the course of a day. This may have as much or more to do with Ed's communications problems than noise. Finally, we found any "automatic" connection between phases could not be counted on. We had success installing bridges between the phases. I seem to recall that a bridge was nothing more than a high voltage ceramic capacitor. It would conduct the high frequency "stuff" around the phase transformers without conducting enough 60 hz to matter. I think you may be able to buy these from the X-10 folks.


October 13, 2005
In response to: Powerline Pessimism
James Borran commented:

A belief that any 50 year old AC wiring is acceptable for high speed data transport is interesting. Much of your AC wiring is likely to be, like the rest of us, made up of a mixture of odd lengths, with tee-and star joints which has probably grown and shrunk over the years. Any circuit probably features a mix of crimp and screw joints. And after 50 years or more carrying a mixture of currents, some high, with heating and cooling, with corroded fuse joints or circuit breaker arced contacts en-route, there remains this belief that such circuits, probably OK for AC, will be just peachy for high speed data. What's wrong with this picture? The power industry has spent many years trying to make PLC (power line carrier) signalling reliable (this is the technology that allows low speed, and I mean really low speed, data transfers possible over high voltage lines) over circuits where joints are way more robust and reliable. Yet, in spite of all the high costs and efforts, this technology remains pretty challenging to use even today. Now we see the industry attempting to send data over domestic wiring at speeds three to four orders of magnitude faster than PLC, and at domestic-level costs. No. Which ever way you look at it, this BPL technology just sounds silly from the get-go.

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