Using the 48vDC telecom line to power things?

[USVIGuy]

I was just wondering if anyone ever tried making a lamp or radio run off their telecom line?

I searched the web and found one company that makes a few cheesy(but expensive) products, that run off the telecom line power.  I was wondering if anyone has ever come across a hobby site or build it yourself site on this subject?

I know this isn't really "Homebrewed Electricity" but I wasn't sure where to put it. So it seemed to fit best here.

[Big All]

Doing so would be theft!

No matter what you think of your telco it ain't a good thing to do.

Powering anything other than a novelty will have the linesman on the way in short order.

Unless of course you are running some kind of pbx system where you supply the line voltage.

There are network setups that have power on them, this way a network router or netcam only needs the 1 wire comming to it.

Look up POE (Power Over Ethernet)

[Chiron]

Telephone lines run on a current loop. Draw more than about 30mA and the telco will see it as being off hook and the current is limited to 50mA in any case. The only thing I've ever hooked up that used power from the telco line was a small neon indicator bulb with dropping resistor across the terminals so it would flash when the phone rang. This was for a fundraising phone bank when I worked for PBS.

When a phone "rings" it sends a 20Hz 90V AC signal through the line. The 50VDC won't fire the bulb but the ring signal would make it flash so the voulenteers could tell when it was thier phone that was ringing The dropping resistor was 220Kohm, enough to fire the bulb at 90V but not enough to load the circuit.

Another problem with loading your phone line is you'd loose volume and probably introduce noise into the circuit, really bad if your using dialup.

.

[srnoth]

Hey there,

What are you considering powering off the phoneline? If you are just interested in getting some free electricity, then yes, it is possible, but the amount of electricity that you can use is so small it's almost not worth it.

Think about it, one of the great problems in RE that is discused on this board it that of wire size. We have enough trouble getting the wires to carry the amperage required over the couple hundred feet between mills/panels and the battery bank. Can you imagine how much electricity can be carried over the many miles between you and the exchange over that thin cable. Probably only just enought to ligh a couple LEDs.

And then there are the other problems others mentioned, that I aggree with.

If you just want to do this for fun, and just for the sake of doing it, then mabye you could try lighting a couple LEDs, but nothing more.

Cheers,

Keep having fun!

Stephen.

[drdongle]

 Being a phone man I just have to put my orr in the water here. Firstly I don't recommend this as there are several problems at least one of which has been covered already, namely the limited amount of current available and the problems inherent with exceeding the current draw that the Central Office will see as an "off hook" phone. Second phone lines are prone to lightning strikes and equipment attached is often damaged or in some cases totally destroyed.

 Lastly there has been equipment designed to charge batteries from the line but the current draw is on the order of a few milliamps so as to trickle charge batteries, if properly designed you could indeed use this a source to charge a battery for a small radio or such.

 Personally I think a small solar panel will provide a more satisfactory source.