telephone line powred charging..?

fever · Jul 2, 2007

hello all,
i saw lot of circuits over net regarding,tapping the power supply from phone lines.i had a doubt in my mind..

if we can get some 5-6v directly from phones line(after dc-dc conversion). is it possible to charge the cordless phone battery from that power?
it doesn't sense good to me.bcz u can't make the power to flow in a loop.
so how practical it is?
pls do post ur views.
regards

Nigel Goodwin · Jul 2, 2007

Don't do it! - it's against your telecom companies rules, and you WILL be caught because they monitor the current taken to identify faults.

audioguru · Jul 2, 2007

The current to charge the battery will make your phone line busy all the time.

Hero999 · Jul 2, 2007

The phone company will knock on your door and disconnect you, they could also take you to court and you'll be ordered to pay them damages.

Leftyretro · Jul 2, 2007

Not very feasible. A telephone subcriber loop, when the phone is 'on hook', will float up to around 48 vdc, however when it detects an increase in current draw due to the phone going "off hook" the then nominal 600 ohm load of the phone drops the loop voltage to around 6-8 vdc. So it may be possible to 'trickle charge' a battery if you could keep the load impedance higher then the 'off hook' detection level. You also have to deal with what happens when a 'ring' signal happens as then the loop has a 90v 20hz signal imposed on it.

Lefty

fever · Jul 2, 2007

Leftyretro said:
Not very feasible. A telephone subcriber loop, when the phone is 'on hook', will float up to around 48 vdc, however when it detects an increase in current draw due to the phone going "off hook" the then nominal 600 ohm load of the phone drops the loop voltage to around 6-8 vdc. So it may be possible to 'trickle charge' a battery if you could keep the load impedance higher then the 'off hook' detection level. You also have to deal with what happens when a 'ring' signal happens as then the loop has a 90v 20hz signal imposed on it.

Lefty

this is what i want to know...
any way thanks guys.i will not mess with the phone lines.
just want to know.thats it.

Super_voip · Jul 2, 2007

it is possible to charge a battery, but at such a low current that it is not pracital for most uses. I used to install telepnone meters which used a 50Hz pulse to earth to activate the mech meter, the batteries were charged from the line.

Hero999 · Jul 2, 2007

What size batteries were they?

I take it they were button cells.

telephone line powred charging..?

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