reduce your phone bill - please read!

[Panda_Badger]

I got rid of my cordless phones ages ago.

I think you're missing a trick Ivan.

Why not use a regular phone, powered from the phone-line.

That way, you don't pay for power used and you're also not adding to the invisible electromagnetic smog with high frequency pollution.

Alternatively, buy a long phone extension lead .

I find in life that the simplest solutions are often the best.

[Ivan]

I agree wired phones are a better option (especially in power cuts!). However, they're not so good for running away from screaming children whilst on the phone!

I had time to do some more investigation this evening. I tried adding a 22uF capacitor to the powerline, and it didn't make the slightest bit of difference. So I tried a 0.01uF in case that would work - no difference. I tried fitting a discharged phone to the handset (=very large capacitor) - that didn't work either. The ferrite bead didn't work either

Looks like I need a proper filter, but I'm not sure what I'm trying to filter out (guess it's harmonics of the power supply switcing circuit). Not sure where to go with it next.

[wookey]

I've just implemented Ivan's 'better PSU' plan on the Bug DAB radio we have in the bedroom (really nice bit of kit). Thatcomes with a fat 2A 9V linear wall wart. Consumption was measured at 7.3W running, 6.3W on standby and 2.3W wil the BUg unplugged and just the wall wart in the wall (eek!).

So on my last CPC order I bought an Ansmann 1612 supply. This is a very flexible device: UK/euro/US/Aust plug fittings, 3/4.5/6/7.5/9/12V output, and 8 plug ends using the now-standard 2-pin +/- switchable interface. 1.6A max output. Costs £10+VAT. http://cpc.farnell.com/ansmann/aps1612-traveller/adaptor-3-12vdc-1-6a/dp/PW01999 There are cheaper supplies which is good if you are sure you'll use it for a specific thing (one voltage, one plug), but this one should be good for all sorts of things, including travelling.

Now meaured consumption is: 4.6Wrunning, 2.2W standby, 0.4W PSU only. That's a saving of 36kWH/yr or £5, so it'll pay for itself in a little over 2 years.

So that's the hub and the bug fixed. Next is the router and cable modem. The tricky one is the power-over-ethernet supply for the phone. I haven't seen anyone selling an efficient one of these yet.

[Antman]

Wookey's suggestion is good - they are some of the better quality interchangeable adaptors that are actually electrically 'safe'. They use a backplate that incorporates a moulded Fig.8 type fully shrouded socket - like the common 'cassette recorder' type mains cables (shows my age!).

There are other cheap imported mains adaptors that use clip-in backplates that have two relatively wide slots in which the live and neutral contacts are very much 'visible'. The slots are not shuttered and are wide enough that we have banned their use here at work (as part of the incoming PAT inspection policy) unless the backplate is permanently glued to the adaptor. You would not want small children around if the adaptor unclips from the backplate whilst it is plugged in....

And no, for the record - "CE marking" means diddly squat as far as electrical safety is concerned.


Beware some of the older analogue phones and particularly answering machines use (and need) an ac adaptor output - substituting this for a dc SMPSU will not do it any good.... 

Antman

[wookey]

'fig 8' is IEC C7/C8 plug/socket. See http://en.wikipedia.org/wiki/IEC_connector for details.