Tap into the phone company's current... if you dare

Ever wonder if you could tap the electrical current on your phone company's landlines (does anyone still use those anymore?) to supply low-powered household gadgets with juice in an emergency (or financial pinch)? Turns out that apparently it ain't too hard to get between 40 and 70 volts (no word on wattage) with a few components and a little time spent soldering. Now comes the second, more PSA-style half of this post. How ridiculously guilty might you feel if a power outage occurred and people couldn't call for help because enough nerds trying to save a buck by charging their gadgets via landline took out the phone company. Sure, it's a dramatic scenario, but we're just saying it's also potentially dangerous, so use this technique wisely. Embedded video after the break.

[Thanks to everyone who sent this in, via Instructables]

[why not the LS2LS7? @ Oct 14th 2007 7:28PM]

You cannot "pull volts from a wall". Volts are a measure of potential, volts don't flow, they just are. Amps flow and Watts sort of flow, since they incorporate current as part of their measure.

And you really shouldn't have posted this article, there's little that can be accomplished by doing this except screwing things up.

[Ryan @ Oct 14th 2007 7:39PM]

Watts is a measurement of power. P = VI, so do watts flow? Not really, it is just a measurement.

It really is no secret that phone lines come with 40ish volts to on them. That is how old pay phones works, they were supplied their own power and also the old school telephones that you just simply plugged into the wall, the power was just there.

The only secret about it, is the fact that it is more lost knowledge among average people now. But yeah, definitely could be easily caught when the phone company gets complaints of DSL speeds sucking, they come out and easily trace it to you.

[kaztm @ Oct 15th 2007 7:07PM]

Hackers used to recharge batteries using phone lines at least in the 80s. It was suitable source of power for trickle charge (low current).

But modern (90s) switches have mechanism to detect such abuse or faulty phone line/equipment. People get billed/sued for damages from the phone company, and arrested/prosecuted for violating relevant laws.

[Joe @ Oct 14th 2007 7:34PM]

Yeah this would be great if it wasn't totally illegal, easily traced and if it didn't drain DSL internet speed.

[nizzy1115 @ Oct 14th 2007 7:35PM]

yeah this was a stupid article that got a lot of attention on digg yesterday so engadget thought they would post it because it is a boring sunday night. this is such a stupid idea.

[Kris S. @ Oct 14th 2007 7:37PM]

I'm going to go try it RIGHT NOW.

[Shane @ Oct 14th 2007 7:43PM]

This really is a BAD idea...

The amount of current that can be drawn from the phone line is very small. In addition, the electronics at the phone company monitor the current consumption to determine the status of a line. You might soon find yourself without phone service if you draw too much current from the line for any length of time...

[atrain @ Oct 14th 2007 7:46PM]

Voltage changes a lot while the phone is both ringing and in use. Be very careful with this, if you pull too much power, your line will sound bad / not work at all, and if you don't have the right equipment , you could do damage to your phones or whatever you are powering.

Specifically, phone lines used to be completely responsible for providing the power to make all the phones in the house ring at once. Now, many phones usually draw power from the wall as well (eg: for the lcd). Some phone companies will still be putting tons of current through the line at that point, so watch out!

If you don't want it to flash when it rings, try putting a capacitor somewhere in the circuit. And, do a dsl speedtest before and after trying this to see if it makes a significant difference.

[metal @ Oct 14th 2007 7:46PM]

So ... this means people didnt know that phones ran on electricity? I mean seriously did they think it was powered by magic?

And I mean, yeah, I guess, sure you power some of your appliances with that power, but all this psuedo legal activity and hardware tinkering to save something around the range of less than a buck a month? We might as well be showcasing you tube videos of lemon batteries powering flashlights.

[Scooter @ Oct 15th 2007 7:25AM]

My laptop's a lemon, would be a good match!

[Tachikomatic @ Oct 14th 2007 7:50PM]

I can see the 11 0'clock news headline already...
"Man starts electrical fire while stealing electricity from phone company, simultaneously knocks out all area landlines and is unable to phone for help."

Having played with power over some extra phone patch cables, they get pretty hot when you are pulling more than a couple amps. I wouldn't try this one.

[Shane @ Oct 14th 2007 7:51PM]

It really is nothing new...Some phones have "extra" features that run solely from the current provided by the phone line but most of these devices have their own AC power brick in addition to the phone line connection.

[Alexander @ Oct 14th 2007 7:57PM]

I do like that it flashes when the phone rings...

[girch @ Oct 22nd 2007 3:19PM]

you can buy strobe lights that are made to plug into the phone line, getting the same result.

[Alexander @ Oct 22nd 2007 3:55PM]

yes, and while realizing this is Engadget, I am much more of the hands-on type. I would rather spend a month making something than buying it.

Yes. I am that guy.

All of the circuits I have seen use a battery to power a light. That's stupid--we have +50v right there! Why rely on something that will die, when we could just vampire off some of that excess voltage? Not to mention most of the circuits I have seen use 1M to 22Mohm resistors--What a waste!

[Phillip Black @ Oct 14th 2007 7:58PM]

"All you need to do is get this hidden source of electricity is.....press the Easy button next to the phone."
Would of been a lot better if it went like that.

[JohnTitor @ Oct 14th 2007 8:09PM]

Oh wow, you guys only heard of KipKay
he can do everything, this is small time

[dj-kenpo @ Oct 14th 2007 8:11PM]

to the people saying it's stupid. it's not. I;ve had this setup for a few months now. I get power outages on occasion, and 3 white leds hooked in don't tap any more juice than a normal phone, and they are far better than "where are the candles" or what can I trip over to find the flashlight.

[Josh L @ Oct 14th 2007 10:44PM]

Indeed, here in Florida, storms knock out the power quite often. The power companies here are used to it (mostly) and it's usually back on again within a few hours at the very most, but having a source of light that isn't a candle or a flashlight (which probably has dead batteries anyway) is a godsend.

That said, having a setup like the one shown in the picture and video up there, or using this regularly or for some high-powered gadgets IS a really terrible idea. Also, does Engadget really think that there would be enough DIYer geeks per capita in any one place to seriously affect phone service or bring down the system? I am sure there are failsafes in place, and if there aren't then we have a much bigger problem than some geeks who decided to try out an ill-advised project they found on the internet.

[johnzilla @ Oct 14th 2007 11:11PM]

How about just buying some wind-up flashlights? You can get 2 of them for under $9 at Costco or eBay.

That's the best source of light there is...if you're alive, you'll have light anywhere you like without being tied to a wall jack. If you aren't alive and can't turn the crank, you don't need the light.

Amazing, isn't it?

[dj-kenpo @ Oct 14th 2007 11:15PM]

I love how all the internet is is one big place where people come in to try to tell soemone else how there way is better. a never ending pattern.

I have a wind up flashlight, my ferret ate the button off it.

the material usage and space requirment of a wind up flashlight is higher than converting the voltage and a couple leds.

some people prefer to do thing son their own rather than just go the wal-mart route. neither route is better, just a preference.

[GameboyRMH @ Oct 14th 2007 11:52PM]

@Josh L

No there may not be enough DIYer geeks in one area, but the geeks start it and then eventually the whole ignorant world catches on and abuses it.

See: All technology throughout the history of mankind.

[Ashraf @ Oct 14th 2007 8:18PM]

wowowow

no wonder the corded phones required no batteries and worked when there was a blackout in 2003.

[Dan @ Oct 15th 2007 5:08AM]

Seriously - you're telling me you didn't know there was electricity in a phone line? What did you think these things ran on? Will power?

[HyperHacker @ Nov 17th 2007 4:34AM]

Actually, I recall the phone lines going down pretty quickly on that day. I picked up a payphone, started dialing, and the entire system went dead. Whoops!

[LukeA @ Oct 14th 2007 8:22PM]

I accidentally zapped myself with a phone wire once. The very old 3-separate-wire kind.

[3rdsun @ Oct 14th 2007 9:30PM]

try getting zapped almost everyday repairing them

[Darkest Daze @ Oct 15th 2007 4:17AM]

Yep, I get zapped by them. While mildly annoying, it's not enough to hurt me, which makes me think it's not really enough to charge your PDA.

[Ratchet the Lombax @ Oct 14th 2007 8:24PM]

This reminds me of a friend of mine who kept having to use her cell phone every time the power went out because her cordless phones wouldn't work. I told her just to get a regular corded phone to use in an emergency since it will work even though the main house power is out. She was surprised that it would work I guess it just goes to show that not everyone knows that the phone company has its own power source.

[zzebi @ Oct 14th 2007 8:28PM]

Actually, tapping into phone landlines is illegal. Just read the fine print in your phone contract.
First of all, it is dangerous because the voltage gets much higher (over 100V if I'm not mistaken) when the phone is ringing, and in the same time tampering with it may disrupt the phone network in the vicinity which can cause serious danger in case of emergency.
Phone companies supply power from high capacity battery arrays so that it is not effected by blackouts of the electrical network. In order not to drain the batteries, all the phone appliances that are legally sold in the US have to use their own power source for anything else than wired voice communication. Since most modern phones have other features/functions too, they need to be powered from the electrical outlet or from their own battery instead.

[David @ Oct 15th 2007 7:32PM]

But what happens with people like me who have phone jacks, but have never had phone service. The phone company is required to have power going to the lines by the government so that I can dial 911. I have no contract with the phone company, I do like the idea of having it power emergency LEDs though for when the power goes out.

[CRH @ Oct 14th 2007 8:48PM]

People still have landlines?

[ethana2 @ Oct 15th 2007 5:09AM]

Well, cell phone companies are incompetent, and so is, uh, Skype.

Once everyone has wireless internet, a la clearwire, and a good GNU SIP phone, landlines won't stand a chance. Right now its bulky and rare. With the gPhone, OpenMoko, and 700 MHz auction, hopefully things change drastically.

With our patent system, the best indicator of progress is entire business models getting screwed out of existence... messed up I guess, but if that's what it takes (and it is) so be it. RIAA, Microsoft, and Verizon? *smirks* Goodbye.

[ubrf @ Oct 15th 2007 6:46PM]

I'm sorry but I couldn't get past "good GNU" because I was too busy taking a dump in my pants from laughing so hard.

[Noah @ Oct 14th 2007 8:55PM]

We still keep our land line in case the power goes out. We (A) hacked old laptop batteries into a power source that charges until the power goes out, and then the phone runs on it to keep numbers and service. This lasts ~14 hours, including ~2 hours of phone usage (so a normal power outage). We also (B) have a non-powered phone that just uses current from the phone lines. It's definitely a good idea in areas where power is frequently out (summer blackouts, wind blowing down trees because we're on a mountain, that sort of thing).

[HyperHacker @ Nov 17th 2007 4:36AM]

You use the phone for 2 hours every time the power goes out? WTF?

[Joey Geraci @ Oct 14th 2007 9:25PM]

Uhm, I don't know if somebody has said this already, but how is this illegal? The power is already running into your home, you are just having to do a little work to access it.

[Dave @ Oct 15th 2007 7:03AM]

It's illegal because it is stealing the electricity. You pay the phone company for their service on a per call basis not on power used, so any power used is not accounted for, so using the power on the phone line like this is theft plain and simple.
You may think it is a trivial amount, just a few watts here and there, but in a country of 300,000,000 it can soon add up.
If you were to put a meter on it and pay the phone company for the power at the going rate, it would probably still be illegal but you might get away with it.

[Joey Geraci @ Oct 15th 2007 10:30AM]

Dave, I really don't think you can just assume that it is illegal. That power is coming into your home, and you never signed any contract with the phone company saying you can only use that power with corded phones. Remember, you are innocent until proven guilty, and I think it would be impossible for the phone company to prove that you knew it was somehow illegal.

[Tracy in Cary @ Oct 15th 2007 1:37PM]

Leeching power from the phone line seems to me the equivalent of getting a company car you can only use for work, and siphoning the gas out of the tank to put in your lawnmower.

But just food for thought, can I leech power out of the cable TV wire?

[Joey Geraci @ Oct 15th 2007 4:45PM]

Except it is understood that a company car can only be used for work, while there is no similar understanding when you sign a lease, rental agreement, or buy a house.

[Othello @ Oct 14th 2007 9:34PM]

This is really old. This used to be around to cut off a forced FBI trace, as the machine they used would supply extra current to keep the line open, and draining it would screw things up. That was the theory anyway.

[Ryan @ Oct 14th 2007 10:06PM]

You've read to many old phreaker txt files.

[Dean @ Oct 14th 2007 9:43PM]

I like how the easy button is just chillin there lol

[3rdsun @ Oct 14th 2007 9:47PM]

The power in the phone lines comes from a bank of batteries giving between 48 and 52 volts DC. This battery power is like the carrier frequency in radio systems where voice and data rides on top. Without the battery power the phone lines would be dead. When an incoming call is received about 115 volts AC is on the lines to ring the telephone circuitry.
Tapping into the phone line to steal power creates a load which can be detected at the Telco. Too much load shuts down the circuitry and creates a fault which someone like me would have to come and fix. So there is nothing such as free power from phone lines.

[dj-kenpo @ Oct 14th 2007 11:26PM]

depends what you're doing. a small voltage converter and a few leds won't draw anymore than my corded phone in the bedroom that also has leds on it. in which case you wouldn't detect it, and it wouldn't blow your lines and you wouldn't need to come fix it. no harm done.

[Charles @ Nov 16th 2007 4:56PM]

An interesting analogy comparing it to a carrier signal, and poses an argument on the legality of a leech device. Obviously if you signed a telco contract that expressly denied you the ability to leech power from the lines, it would be a breach of contract; ( but possibly not "illegal" past that ).

However, the FCC states that you cannot cause interference and must work to the best of your ability to resolve interference etc.. etc.. (see: http://www.fcc.gov/oet/info/rules/). Therefore, even if you never signed a contract; it may violate FCC rules..

If somehow draining power (however you wired it) disrupted 911 service, that could be a real issue.

I notice now that almost all of the references in the FCC rules explicitly talk about radio frequencies; so I doubt a proper judge would apply those rules to telco lines. (See: Sec. 15.17 "Susceptibility to interference." )

As far as the actual device goes,
15.23 "Home-built devices" states that any "home built device" does NOT need to be "authorized", as long as (15.23b) the engineer is "expected to employ good engineering practices to meet the specified
technical standards to the greatest extent practicable."

So, I would say that if you tried your best to design a device that drained only the power that a normal telephone would drain under all circumstances, and maybe filter it back into the power grid (make a few bucks) there is no viable reason to think that it would somehow disrupt 911 service or telco service- and therefore is not illegal.

There could be a serious problem with the new broad anti-terrorism laws however, they might try to say you were attempting to disrupt emergency services (insert headache)...

[Philip S @ Oct 14th 2007 10:07PM]

It's always amazed me that they can send power and voice/data down the same 2 wires.

[computer.dude.28 @ Nov 8th 2007 7:21PM]

it also amazes me how they can send cable internet forward and backward, and 5 video streams through one coaxial cable.

[Tristan @ Oct 14th 2007 11:18PM]

My dad who was a telstra tech here in AUS made a unit about 20 years ago which was a ringer extension which doubled as a 9v battery charger, sure it took a week to charge the battery, but it was free, the current running down the phone lines is pretty small, and as everyone has said, if you drain too much you are going to lose line quality. But realistically, the price you pay to charge a 9v battery, doesn't really weigh up to the cost of the components.

PS, with such low current, any voltage coming through the telephone lines isn't going to be dangerous. To help protect the batteries it is quite easy to separate them in a ringer unit when the phone actually rings.