I guess that meters block the signal from reaching the rest of the street because they have big inductive motor windings in them. But what about the new-fangled digital meters, like I've had for the last few months? I think they just have a few mili-ohms of series resistor. Will they block the signal?

This has been brought up before - all this is fine and dandy, security wise, as long as your neighbours don't have any of these units on the same loop either. Think about it.

Has anyone tried plugging one into a neighbour's power socket to see if there is data isolation between houses due to the inductive coil in the 'traditional' meter? I suspect that the new design meters, as described by Phil, would offer no blocking at all.

Another area to consider is stray r.f. radiation from your mains wiring. If you connect a high frequency source (powerline ethernet adaptor) to your mains wiring then your entire house will act as a transmitting aerial. It may be that the closely laid together live/neutral wires have little radiative effect, has this been studied? If this does happen however, then you really will need encryption enabled. Having said that, it would need some very specialist/custom equipment to monitor and decode any data leaked outside in this way. Once again, has this been studied?

"Setting the password requires a button push on the unit that's being added *and* on one of the boxes in the network it's joining."

Ah, arse - that'll be me not reading things properly. Nuff z.

Cheers

If you live in a street, your house and your immediate neighbours are plumbed into adjacent phases of the mains; and there's no way that any frequency higher than a few hundred Hz is going to get through the thwacking great three-phase transformer in the sub-station. Somebody three doors down possibly could see your network; but electricity meters are inductive and block out high frequencies. Mechanical ones because they have to be inductive in order to work, and electronic ones because they have to be inductive in order not to be ..... er ..... misled by spurious signals on the wires (imagine the horror if someone's electricity meter were accidentally to clock up credit that hadn't been paid for because someone clicked a piezo lighter next to it).

RF coupling is an unlikely prospect. The houses in any street probably were rewired at different times, so the cables are unlikely to be exactly back-to-back. Then there are at least two layers of brick between any two houses; call it 225mm. In modern houses with cavity walls, it will be more. The live conductor is adjacent to the neutral and earth, which are joined at the meter if you live in a city, and certainly less than 10mm. away. I'd say it ought to make a fairly effective shield.

Let us not forget that when you announced the thing a month ago:

http://www.reghardware.co.uk/2007/11/13/solwise_pushes_powerline_sec/

...you made the horrendous gaffe of saying that you could add a new unit by only pressing the button on the new unit, not the other(s)!

Curiously that seems to have slipped your mind now you're correcting someone else who's made the same mistake...

Great. Yet another product with a light that changes from red/green/amber/orange/whatever. I'm fed up having to ask the family or anyone in the office if things are on/off/errored because lights change between red and green. Manufacturers - my guess is lots of buyers of kit like this are male. And around 10% of men are colourblind. It would only cost pence to add multiple lights for the different speeds so the position of the light would be the indicator. Well done Sony for making the PS2 have a nice big blue light.