Introduction: Private Phone Line for Under $10

Picture of Private Phone Line for Under $10

I will teach you how to make a private phone line with two non-cordless phones with stuff you can find mostly around your house! Great for kids and there clubhouses!

Follow my instructable and/or just watch this step by step video

If you like my instrucables PLEASE visit my Metacafe channel and watch the videos and give them 5 stars and or digg them.

Thank you so much enjoy,

Step 1: What You Need

Picture of What You Need

The items that you need are:

2 phones (dont use cordless, well you can if you want...)
2 phone cords
4 alligator clip leads
1 300 ohm 1/2 W resistor
1 9V battery
2 phone jacks

Step 2: Connect Your Phones to Wires and Jacks

Picture of Connect Your Phones to Wires and Jacks

Okay first thing we do is connect our phone cords to our phones.
Then we connect the other ends of the cords to our phone jacks.

Step 3: First Alligator Clip

Picture of First Alligator Clip

Now take one of your alligator clips and clip it to the red wire (metal part of it) on the back of one of your phone jacks.

This part can mess up if your phones work so make sure the alligator clip is on right.

Then take the other end and clip it to any end of the 9V battery.

Step 4: Second and Third Alligator Clip

Picture of Second and Third Alligator Clip

Now we take another alligator clip and clip it to the other side of the 9V battery.
Take the other side and clip it to one side of the ohm resistor.

Take your third alligator clip and clip it to the other side of the ohm resistor.
Like before now we take the other end of this alligator clip and clip it to the red wire on the other phone jack.

Step 5: Last Alligator Clip

Picture of Last Alligator Clip

Finally we grab our last alligator clip and clip one side onto the green wire on one phone jack and the other side onto the green wire on the other phone jack.

Step 6: Talk Away!

Picture of Talk Away!

Now make sure all connections are secure and your phones will work! You can now communicate between both phones

They will work for as long as your wires are so you can span them across your house, or even to a neighbors!

Like I said before you can choose to solder your wires for a more secure connection too.

Hope you all have phun with your own private phone lines!

(Stay tuned for the next instructable which will teach you how to make them ring, this is a bit costly though =/ )

If you like my instrucables PLEASE visit my Metacafe channel and watch the videos and give them 5 stars and/or digg them.

Thank you so much enjoy,


agnestre (author)2011-09-14

Is 270 ohm 2w OK?

Wasagi (author)2010-07-17

This is excellent!! I was thinking of rigging up the local storm drains with something like this, and maybe even use some doorbells as ringing devices... hmmmm

Mavamaarten (author)2009-04-24

Nice, but kinda stupid to talk like this. a LONG cable running from phone to phone ? NO thank you. nice instructable tho

danielemur (author)Mavamaarten2009-11-12

You can use two cordless phones.

wombat99 (author)Mavamaarten2009-08-20

Well, it's not something for everybody, but (IMHO) it's a nice idea if you have small kids. This is the kind of thing that if I put one in my son's playhouse and one somewhere else he'd use it on playdates ("Hey Jimmy, you better to get the base -- there's a secret message coming in!"). A non-DYI solution (which includes ring) would be a "ring down" box (or line simulator, line tester, etc). Viking makes one. These can be expensive brand new, but can be found at ham fests, eBay, etc from time to time. But I'm not trying to take away from this Instructable -- good job, Flippi273!

danielemur (author)2009-11-12

If you didn't have the resistor than what voltage would you supply?

condoritos123 (author)2009-08-12

thank you, I don't know so much english, but i needed this... i'll try it in my house

Ezza (author)2007-11-22

This is a really sweet idea. Can you make the phones ring or do you just pick them up to talk?

Flippi273 (author)Ezza2007-11-22

I actually do know how to make them ring, but you need extra hardware which cost some money, so once i get some money get all the stuff ( im a poor teenager haha!) ill show you guys! but right now u just pic them up and talk

psptubefreak (author)Flippi2732009-07-23

lol im poor aswell...although,im 14 and have a

oh and also,it would be easier to hook up two LED's to switches and a power source,so if you wan someone to pick up,flip the switch to tell the other person to pick up

perlpower (author)Flippi2732007-11-23

To make the phone ring you would want about 90V @ ~40Hz AC sent across the line and you would need to remove the 9v battery as you send it.

luigi2999 (author)perlpower2009-01-29

no, all u would need is a diode to prevent flow to the + terminal of the battery

lopez8675 (author)2008-07-03

couldn you just use a corless phone, have someone have the base, other people use all the handsets and use intercom?

extremegtafan (author)lopez86752008-07-29

Some of us can't afford fancy multi-handset intercom phones.

lopez8675 (author)extremegtafan2008-08-02

how much do u think they cost? i saw one at bennys for like 20-30 dollars.

ReCreate (author)lopez86752009-03-18

oh,wow that's cheap i probably will buy that tomorrow ill see if it works

luck (author)2008-05-29

if i use a cordless phone will it run the 9volt dead quicker than with a wired phone

ReCreate (author)luck2009-03-14

no,not at all just connect the base to power

luck (author)2008-07-30

What would happen if u dont use a resister

ReCreate (author)luck2009-03-14

the phones would both blow up and catch on fire

agis68 (author)2009-02-23

Very good the idea is very old but nice work. Back to 50's-60'sand 70's in big offices when the electronic telephone lines doesn't exist the unique way for interior communication was that way. So everybody had his own telephone device and they could communicate each other. Here in Greece was very popular and in the years of Dictatorship some guys trapped these telephones to record the chats and these machines had the nickname: Gossip, or Rat or Bug

heartlessangel7 (author)2008-11-07

Ooohhh, I want this for my secret base.

Derin (author)2008-10-17

ill try one day...

munchman (author)2008-09-14

I am going to do this. Also, a tip: for those that want to use this for an indefinite time, wire in a 9V DC adapter instead of the battery.

Inovative Invintor Joe (author)2007-11-29

have you come up with a switchbox for multiple phones... if you had for instence 8 phones and you wanted a switchbox is there a way to have it so that you could assign each phone a number and then you can press the number on one phone and it be connected to that number pressed?
this guy did it, though not the simplest of designs. could replace a lot of the discrete logic with a microcontroller or an FPGA

I believe it could be done because i do know how to make the phones ring, but you need a bridge which i cant get my hands on right now cause its expensive haha, but when i do i will show how to make the phones ring and look into making it so you can dial a number.

Jakeg (author)Flippi2732008-06-10

plz plz make one that rings. PM me when you do!

Gamernotnerd (author)Flippi2732008-03-31

you need 90vAC~20Hz for ring

luck (author)2008-05-29

do u apsolutly need the 300 ohm 1/2 w resister or will it fry the phones if u don't use it

Braeburn (author)2008-05-04

to the thrift store next door!!!!!!

dean-101 (author)2008-03-23

you could also add a buzzer to each phone an a switch so u can ring the other person

Gjdj3 (author)2008-02-02

cool. *favorite* *+1*

huang.wencong (author)2008-01-02

Cool! I like it! I installed one too!!! Can I use it for multiple phones (like conference)?

yes this will work fine with multiple phones, just wire the extra ones in parallel.

infotransfer (author)2007-11-28

what would happen if you did it without the resistor?

Flippi273 (author)infotransfer2007-11-29

Well the phones require 8.5V and with the resistor that makes the voltage 8.5. So without it it would be giving it .5 more volts than it needs. So basically what happens when you give something too much electricity ;)

infotransfer (author)Flippi2732007-11-29


rc jedi (author)2007-11-23

cool, we do use this system at wk. we glear wire pairs by clipping on 1 good known pr and talk between testers in just that way. Well, i usually just use the cell now, if the work is just for a couple of minutes! talk current is low, about 20 ma i think. idle battery voltage is 48v but drops quite low when connection is established. 9v is good enough.

sonnimo123 (author)2007-11-23


GorillazMiko (author)2007-11-23

sweet like chocolate. errr i mean... awesome instructable.

!Andrew_Modder! (author)2007-11-23

oh w8 is this like a...what do you call it.. So basicly it just lets you talk to ppl inside your house?

Well you could have it hook one phone up in a club house, and then one to your house. Could put one up stairs and the other downstairs. This is mostly designed for kids haha

ya ok. lol when i was younger i would have LOVED this, but now its so so :-P but for younger kids, they would love this!

futeng (author)2007-11-22

do you know how you can do this without wires?

Flippi273 (author)futeng2007-11-22

You mean like using a cordless phone correct? all you have to do is the same thing except plug your cordless phone base into the wall ;-)

gamer (author)2007-11-22

when i was smaller i made one with the same disign except 1. it plugged into a wall transformar instead of a battery, and 2. i used a coil to absorb the waves so they dont ge and charge the battery, cause i would get a bad sound. then i put long wires on it, and put a phone in my room, and one in my brothers, and it work really good. nice insructable -gamer

About This Instructable




More by Flippi273:Private Phone Line for Under $10Implode a Soda Can
Add instructable to: