Original URL: http://www.theregister.co.uk/2012/11/14/plt_standard/
EU standardises hamtagonistic powerline network tech
Bearded brotherhood pledges eternal vigilance
The second vote on EN50561-1, the EU standard for running Ethernet over mains circuits, has passed, putting the standard on the books, much to the annoyance of the UK amateur radio operator community.
EN50561-1 requires that all Powerline Telecommunication (PLT) kit, which carries networking signals over the mains electrical wires, must avoid the amateur radio frequencies; switch off when not in use; and keep transmission power to a minimum. All powerline networking kit sold in Europe will have to conform to it within the next three years, though it clearly doesn't go far enough for some.
UK hams, in the body of the Radio Society of Great Britain, have long opposed the standard, arguing that existing requirements that no device generate undue radio interference should be applied to PLT devices, which would make the vast majority of those in use today illegal.
Appeals to Ofcom and Trading Standards failed to get any traction, with Trading Standards deferring to Ofcom while the radio regulator pointed out that it has no power to govern devices that were not designed to emit radio signals. PLT kit is supposed to only send signals over mains wires, but as such wires are unshielded it inevitably leaks out. Ofcom did extend its remit for the Olympics, giving itself permission to shut down any radio transmission regardless of source, but that right ended with the closing ceremony.
Those backing the new standard argued that while imperfect it was better than nothing, and that it could always be tightened up later if problems emerge, not to mention that with powerline kit so widely deployed it was too late to rant from the sidelines.
Having failed to get existing standards applied, and failed to generate enough support to prevent the vote going through, the RSGB has conceded that EN50561-1 is here to stay and is now focusing its efforts on gathering information about interference with a view to tightening up the standard.
Part of the problem with PLT interference is that no one knows how widespread it is. Existing systems generate interference which pushes up into the AM/FM and even DAB radio bands, and with harmonics could extend down into the ADSL+ frequencies. The latter are only used over phone lines, but as such lines often run alongside mains cables there is potential for interference there too.
The problem is that when AM radio drops out, most of us just move the radio or fiddle with the antenna, whilst a slow internet connection will be blamed on sub-standard copper or just distance from the exchange, before one starts to suspect the PLT device. Ofcom reports only a handful of complaints, and all from radio hams, but as the regulator no longer fields complaints about radio reception (they go to the BBC these days) that's hardly surprising.
Having a standard is obviously a good thing, and PLT kit now has one, but only the amateur radio operators will notice if the kit we buy is conforming to that standard - so we should be grateful that they plan to check. Otherwise we'll miss the interference from our PLT devices entirely and just blame the rest of our devices for failing to live up to our expectations. ®