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!

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Step 1: 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
Is 270 ohm 2w OK?
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
Nice, but kinda stupid to talk like this. a LONG cable running from phone to phone ? NO thank you. nice instructable tho
You can use two cordless phones.
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!
If you didn't have the resistor than what voltage would you supply?
thank you, I don't know so much english, but i needed this... i'll try it in my house
This is a really sweet idea. Can you make the phones ring or do you just pick them up to talk?
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
lol im poor aswell...although,im 14 and have a job...lol
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
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.
no, all u would need is a diode to prevent flow to the + terminal of the battery
couldn you just use a corless phone, have someone have the base, other people use all the handsets and use intercom?
Some of us can't afford fancy multi-handset intercom phones.
how much do u think they cost? i saw one at bennys for like 20-30 dollars.
oh,wow that's cheap i probably will buy that tomorrow ill see if it works
How much money do you think people have? Think about this for a moment. If you have a job that pays $8.00 an hour, and you work 40 hours a week, that comes out to a gross of $320 a week. If you're single then take out 25%, or $80 for taxes, and that leaves you with $240 a week to live on. Take out your money for rent, utilities, car insurance and repairs, gas, and food, and then you really don't have very much left over to play with. Considering that $30 can pay for a weeks worth of groceries, it's not really worth spending the money on a fancy cordless phone setup just to play around with. It's not a question of how much something costs, but rather how much money you have to spend, and what you'll have to give up to be able to buy it. Consider this the next time you look down on people that aren't able to afford some fancy little gizmo.
great lecture!
very true....
of course,I think of very true things
well, why wouldn't you :P
yes why wouldn't i ? im a genius,thats why
hey, im just telling what i saw. never said you had to buy it.
its just that someones takes things to seriously
really,don't take it too seriously Sometimes people can cough up 30 dollars for a project,And besides Sometimes people already have the stuff they need,or they find it in someones trash. Really its not that expensive
if i use a cordless phone will it run the 9volt dead quicker than with a wired phone
no,not at all just connect the base to power
What would happen if u dont use a resister
the phones would both blow up and catch on fire
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
Ooohhh, I want this for my secret base.
ill try one day...
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.
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?
<a rel="nofollow" href="http://wandel.ca/homepage/pbx.html">http://wandel.ca/homepage/pbx.html</a><br/>this guy did it, though not the simplest of designs. could replace a lot of the discrete logic with a microcontroller or an FPGA<br/>
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.
plz plz make one that rings. PM me when you do!
you need 90vAC~20Hz for ring
do u apsolutly need the 300 ohm 1/2 w resister or will it fry the phones if u don't use it
to the thrift store next door!!!!!!
you could also add a buzzer to each phone an a switch so u can ring the other person
cool. *favorite* *+1*<br/>
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.
what would happen if you did it without the resistor?
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 ;)
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.

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