DIY Hacks & How To’s: Emergency Power from a Land Line

What do you do if the power is out, but you need to charge your cell phone to make an emergency phone call? In this episode of DIY Hacks and How To’s, Jason Poel Smith shows you how to tap into a land line. Read all about it at and check out the complete how-to at


Elixi Bizkaia says:

Can I power my adsl modem from phone line?

1David leonard says:

who’s watching this when there power is out and like

Oskar Balcerzak says:

Buck converters are more efficient.

Aaron Cooley says:

I have a question, what is the most compact way to turn 50 volts into 110 volts to say run a tv or something?

Naufal Aziz says:

awesome, thanks for making this tutorial

Magyar Harcos says:

youre a fucking tool. if you are into electronics youll have a gas soldering iron


what if I stopped paying for phone service a few years ago Will it still work

Avi Carmi says:

SERIOUSLY not a good idea. Even a minimal amount of current draw on that line will be interpreted by the telco switch as an “off hook” condition, which means allocation of resources to your line to allow for a phone call. NOT a good idea.

Also… TELCO sends a high voltage burst down the line to signal a “ring” condition. If not anticipated and handled properly, it can damage illegal, parasitic equipment.

KB_Playz says:

USB Killer as a dead drop xD

b0rd2dEAth says:

I needed to know how much voltage is passed across the 56kb line, looked everywhere for that information.. Glad to have found it here. 0:33

Dennis Garvey says:

Well why don’t you user your landline to actually make the call

Power Max says:

Based on your data I figure you can achieve optimal power at 26V @ 41.4mA, if you feed that into a small switching buck converter, that should ideally yield 5V with as much as 215 mA of current available. Assuming 90% efficiency, that drops to about 193mA. Much better than your 7805 regulator.

fardin ahmed says:

how can I save my phone from any kind of damage what should I use from any kind of damages

Nico Liguori says:

if i put a invertor 48v to 110ac before invertor a resistor so i will not pay eletricity

Nekowafer says:

Ok so ur saying unplug your home phone, make an adapter, and then charge your smart phone with that? Why?

kulgan96 says:

there must be some irony charging your cellphone with the landline

akhlish Unani says:

few questions:
How to use the diode to keep the circuit safe
Can we make it 12v 1A output? if yes how to manage when when landline rings.

Naji AL-LAHABY says:

it’s goooood idea. it’s very important now in Yemen thanks

Dan Kirchner says:

wats a landline ?lol

XPGaming says:

Just use a power bank!!!

fardin ahmed says:

Will this be dangerous for battery or any of short circuit or any of damage to phone

Kamal Aziz says:

Yes it works fine for 5v and 12v , but when phone rings it make a troubled song…. !!! is there any way to correct it ?

Thushara Fernando says:

does the voltage regulator used here has the same effect as a buck coverter, for example if a 9v 100ma is reduced to 5v , then you can get 0.180 ma, is this the same with the voltage regulators, i thought that they just drop the voltage by wasting power? simply does it honour the v=i*r ? sorry for my bad english.

Milk Parker says:

This is useless because I have a modem that puts out the power to the phone line. If no wall power then no phone power.

Cris Bessette says:

I’m sure these problems have already been mentioned:  1. The land line has to be ON- someone paying for the service.  2. Land lines detect OFF HOOK status (someone wants to make a call) by the amount of current draw, anything more than this charging circuit would be seen as OFF HOOK, and the phone line would be eventually turned off by phone company if off hook for very long.  3. RING VOLTAGE is up to 90 VOLTS, if someone calls this line you could possibly blow up anything connected to the line that cant handle that voltage.

Inf3ct3d101 says:

Would a BR805D and a LM317MP work for this?
They were the only ones I was able to find at my electronic store.

Taha Koçbıyık says:

where are you form? ???

bestjunky says:

A thing to keep in mind is that plugging any non-FCC certified device into a phone line is illegal in most states. If you happen to blow the circuit, not only will you be on the hook for repairs – you may get sued. With a hack like this it’s unlikely you will cause damage, even if you short the connection. However if you try, say, making a custom phone line interface, a makeshift dialer or some sort of home automation gizmo where phone company can detect signal deviation and figure out what you’re doing – you’ll be in trouble. Just a word of caution.

Corey Mcniel says:

I made it by myself. I used inplix scripts for that.

tomas kantor says:

Does anyone know if it’s possible to hook up a power invertor to this? And power computer or something?

Aisha Love says:

This is highly illegal and if they catch you the penalties are really damn steep and can even lose you your internet service if you use idsn or dsl.

ElecDiy says:

There are many things wrong with this video. The first one is lines work with voltages ranging from 40 to 90 volts DC, 7805 regulators aren’t designed to work with those voltages, they could be damaged and let the input voltage into your phone, probably destroying it, they are also extremely inefficient. The second one is the current provided by phone lines is 100 to 200mA, by using it as a phone charger you’re straining the line and disabling it, if enough people did this you could disable the network and have technicians knocking on your door. It is also illegal in some places, but I can cope with that.

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