DIY Hacks & How To's: Phone Intercom 

Hi Brandon Francey I was just wondering where on the circuit you added the LEDs - Your idea sounds interesting. Thanks

How to add led light and the buzzer. Will u please tell me about this

Dude , would love to know how you configured the led in it. Thanks :)

Could you tell us where on the circuit you added the led lights?

Sorry guys. I never received a single notification until today for some reason but I'll tell you exactly what I did. I picked up 2 external phone jack boxes. They are little plastic cheap boxes you plug your phone into. I ran CAT5 cable (4 pairs) between them because it's what I had but CAT 3 (2 pairs) would work too. In each box I drilled a hole and added an LED light. Then wiring isn't too hard once you understand it. For reference CAT 3 wire pairs are Red Green, and Black Yellow. The thing to keep in mind is we are making a simple circuit. With 1 phone in the first jack box we would go, battery + -> resistor -> red wire - >phone -> green -> battery - The circuit is completed when we pick up the receiver or push talk on a cordless phone. We could slip in an LED anywhere in this circuit and it would light up when we pick up the receiver but all that tells us is when we pick up the phone, and we already know that. To add a second phone we add the CAT 3 cable and connect the red wire to the same place as above to the resistor which goes to the second box. When a phone is connected to the second box, power comes back on the green that goes to battery -. If I add an LED here, it will tell me when the second phone is picked up. To tell when the first phone is picked up at the second location, I need to send power back up to it so on the first phone, instead of connecting the green line to negative, I connect it to black wire which goes to the second box, add an LED there between the black and yellow, and power comes back down yellow wire to finally get connected to battery - When I added the buzzer, I was using CAT 5 so I had 2 unused pairs. I just used one to make a simple circuit of battery + -> momentary switch -> buzzer -> battery - Button was on my side, buzzer on his.

it should work too!!

Has anyone figured out how to do that?

LOL, exactly what I was thinking!

just do a web search on how to build a Frequency Shift Key Modem. you can even program numeric designations into it and have phones all over the house with your own private phone network.

you could hack into button on the phone or add one, add an extra few wires to the cord (or us an ethernet cable and swap the jack for the phone jack and use the extra wires in the cable to add an extra connector to wire up a switch. and a buzzer, then on the other end set it up so that the switch on one phone taps into the buzzer and vise versa. if you wanted multiple phones and wanted to select who gets the buzz you could add a selector switch to the phone. (or use the dial pad and each button could be for a different phone.

phone intercom | austinscreations3000 this might help. (my personal website)

thanks.

You need to safely impose 120 volts AC into the low voltage DC system you just built. Use a momentary push button rated for 120 volts to make the phones ring. ( They will both ring together when the button is pressed. )

Queria saber tambem

Yes, it would work, but you have to be very careful and figure out which wire to connect

Or just use walkie talkies. Then you're not fixed into set positions, should you have to move.

on very old phones, you just need to push the receiver switch a few times on any of the phones, and the other one will start making noises...

That is why you need a resistor

@@turbojurpo , wow I guess better late than never.LOL. Thanks for the input. I have installed this project (using a 9VDC converter at several location.); it has been a huge help.

And also if possible to add a ringer

Landline is required. You can't do anything about it

Not many since your talk battery will be so low.

You can watch one of electroboom's video

Make: ^^^^^

Lachlan Black two wire u can get a cheap phones at walmart

yes, but it would get a little more complicated

No. Resistor is required, or else it would fry the phones

you can also use cordless phones, fax machines etc.

Kavindu Gilshan 600 oms

no

Endless

Long enough for any house. You might run into issues over a thousand feet or something. That's not a hard figure, I just mean at some really long length the power will attenuate to the point that you won't be able to hear the other person. There are calculations to figure out voltage drop.

60+V, 20Hz, and you're in business.

270-330 ohm

Watch the whole video ;)

search project boxes - available at radioshack

search in google or electronic shop projectboxses

Yes, it does actually matter

No. This is strickly between the two phones

Doesn't matter ig

It's too much it would fry the telephones

Did you skip physics class?