9 Volt, Battery Powered, Telephone Intercom System

[@lovespreadsheets8769]

This brings back memories. In sixth grade science class back in the 1970’s, we had old crank telephones from the early 1900’s. We would connect theme to a (I believe it was a called a #6 dry cell ignition battery). The battery was circular and stud about 8” off the table with stud and nut terminals on to hold down our wires. We also connected old boon box like speakers and talked to each other. If my memory serves me correctly, the speaker could serve as both the microphone and speaker at the same time. I have looked for those circular batteries several times over the years to no avail. I wanted to try this experiment again. Perhaps I will try using a 9 volt.

[@gregschneider8113]

great video... I also looked beyond to make a ringer or signal across the classroom... with little luck (easy). Your electrical knowledge make me envious.

[@radioraggamorffa_]

Thank you, you could also use a wireless door bell too to use it as a ringger, they are pretty loud and you can operate them from the bottom or from the actual bell too....this is a great idea for a treehouse, i am wondering how much v I need to add 3 or 4 phones.

[@RAC7012]

Would this circuit work if you only connect the hand sets. I want to put alligator clips on the ends of the wires coming from the hand set so I can clip one lead to a single conductor and the other lead to ground. So I can do wire checks with someone at the other end of a Multi conductor cable. For example we would talk on the blue wire and move the the purple wire then move to the orange wire, and so on.

[@michaelbeggs2013]

try hooking in one of those hand crank phone chargers to see if it puts out enough juice or use a piezoelectric buzzer as a ringer.

[@fnsimple]

That’s how the army did it on the TA-312 field telephone system

[@reynardmisae6208]

I tried to rebuilt this project using two rotary phones, they work fine except that neither of them ring. I think it is due to the different voltage from a direct phone line and a 9v battery?

[@michaelosmon]

Ringer....2 n/o push buttons in parallel, 1 at each phone. Either will trigger a 555 timer in monostable set to stay active for 20 seconds, which triggers another 555 timer in astable which is running a small muted siren and or led at each button. But you'd need 3 pairs then and older home phone wire is 2 pairs. I want to make this. Thanks!

[@F1shard]

Great video, any idea why the resistor is needed? I tried this with 2 phones, 2 9V batteries and it seems to be working fine. 1 battery alone would not work for me either.

[@F1shard]

+F1shard I did not use a resistor

[@Skinnyrd]

+F1shard Thanks! Analog phones come in many different forms. The internally circuitry is not always the same. My friend was able to power his phone off of one battery and no resistor. Another friend of mine ripped out the dial pad and powered it with a 9V battery. You have to take a look at what you are working with internally. The resistor is supposedly there to help limit the current on some instruments. I've run into some funky analog phones before, so I guess it could be helpful to someone. In a normal analog phone, when on-hook the phone actually expects to see up to -48V. When the phone is off-hook, it usually expects between 3 to 9 volts at 30mA to 40mA. This can vary a few volts higher on some systems.

[@F1shard]

+Skinny R&D that's kind of what I was thinking. Thanks for the response. Interesting to hear others are having different results as well.

[@MonstarMk3]

The resistor will change the sound and volume. And the ohms will affect the volume. They will also roll off bass frequency. I would really consider using one. I would try a 500k potentiometer as well. it is passive and needs no power. It increases your volume and gives you control over it. If you look up a G&L Legacy (USA) schematic. They have a all passive design with a volume, treble, and bass. It would make you much louder, and you could fine tune the sound quality.

[@ДжонСора]

Some modern phones need only 12V AC to ring. I've used an old ADSL AC->AC power supply in my experements.

[@unixd0rk]

for your LED "ringer", you could use an optocoupler and some arduinos or PIC chips to do some fun things. I like a good analog solution better, tho.

[@radioboy75]

"Dial tones" are not the tones you get when you push a button on the phone. You mean "touch tones" or DTMF. A dial tone is only provided by the phone company or a special system.

[@UZI9MMAUTO]

Why not use a hand crank. From a radio or flashlight into the circuit. Once line #2 picks up it , then stops. It's same concept of field phones.

[@fnsimple]

The TA-312 field telephone

[@thewaytherobbinsfly3927]

Do you have to have a phone line for this to work?

[@nilmur]

Would it be trivial to add a single led to indicate either phone is off the hook?

[@reynardmisae6208]

Could you possibly show the result of the project on how it works? Do you press a number and it rings? Or how?

[@realSamAndrew]

Is there a way to use this method if you want to connect a phone device to a computer to upload or download the data files where it depends on a landline dialup but you don't have a POTS landline? How would you get the 2 sides to handshake if you don't use a telephone number or a dial out/answer procedure?

[@ronb6182]

It's not needed in this setup. You can do the same with just a couple of handsets If you want to dial a number to make the other phone ring you can use a phone line simulator we had some where I work. You program a phone number in and when you hook up the two phones you can call each phone. The phones can ring if you make a call to the other phone. 73

[@realSamAndrew]

@@ronb6182 interesting. Please explain further. It appears your comment was cut short at the end.

[@ronb6182]

@@realSamAndrew if you are talking about phone line simulators. They are a phone system in a box. They can be programmed to a phone number and some have four lines I used two lines for express net a rate and bookkeeping program . But if you have 4 phone lines you can set up each phone to. Number you can pick either 3,4 ,7 or ten digits I haven't tried a country code. For intercom it's best to use 3 or 4 digits . 73

[@realSamAndrew]

@@ronb6182 ok, so where can I find a phone line simulator these days? And what is the 73 at the end? 🙂

[@gabriellelapalme1417]

Hi there! How would it work with the telephone cable that have 4 ends?

[@mattbarker3789]

How long can you make this with a 9 V?

[@13klivvsasd75]

Does it have to be on the same house?

[@memoonaafridi1859]

Please tell me how much thing u used give the name in list... Reply

[@sonder2164]

What's the estimate usage time before the battery goes dead?

[@wildfernweddings4187]

How long would this battery last?

[@hunterluxton5976]

Is it passible to ring up the other phone?

[@Weatherman40312]

Not without ac capability. Hand- cranked electricity should work.

[@GRAVESAUDIO]

I made this but am getting a loud feed back out of my speakers? any help would be great! Also i dind use a resistor is that the problem?

[@greenolive1278]

Yes that’s the problem

[@8bit_coder]

Your handsets are too close, so the phones are way too sensitive.

[@Takisarebetterthanfritos]

What would happen if it was a 48v battery in between

[@seanjuth]

The resistor doesnt really matter. Without it voices are really loud

[@escapetoparadise2226]

Anyone figure out how to make ring yet?

[@ypop417]

Phone wire cable has 4 wires could you use the other 2 to make the ringers work?

[@Takisarebetterthanfritos]

I think u can use them for a light, but u would have to see it when it lights up or it would have to be in a dark room.....why not just use your cell phones I mean seriously

[@franklinmckenzie8856]

@@Takisarebetterthanfritos I would do this for my kids. They don't have cell phones, seriously.

[@Takisarebetterthanfritos]

@@franklinmckenzie8856 oh ok. I didn't think of that

[@MrWoodchuck59]

@@Takisarebetterthanfritos I am trying to find a way to do this at my camp where there is virtually no cell phone signal.

[@Takisarebetterthanfritos]

@@MrWoodchuck59 could walkie talkies work

[@allanegleston13]

howdi. a fellow on you tube by the name of thomas kim who has a circut called a " telephone intercom w ringer signal generator. hope this helps .

[@Skinnyrd]

+allan egleston Cool. I'll check it out. Thanks!

[@Satchmoeddie]

No no no, I want a real genuine PLAR system. Private Line Automatic Ringdown.

[@BellTechnical]

Seth B Like a tone remote intercom? I use two Motorola T-1300 tone remote desk sets connected with one pair of telco cable. They work fine. No need for a ringer. While the handset is cradled the phone's internal amplified speaker is enabled.

[@erintyres3609]

On eBay you can buy a used "Teltone TLS-4" or "Teltone TLS-5". It has four phone jacks, dial tones, accepts pulse or tone dialing, the phones ring when you dial, you can have two conversations at a time, etc. You can assign a phone number to each line, and it even does conference calls and caller ID. It has absolutely no ability to connect to the public phone system but for an intercom system it works great. You might have to pay $150. A used PBX costs just as much, but is so complicated that it would be totally hopeless for most people. The Teltone is not too difficult. Its instructions are available as a PDF online, and it is easy to use with its default settings.

[@gopalkulkarni6060]

बकवास, does not work. I tried it. Misguiding video. Technical aspects should be clarified.

[@Skinnyrd]

Hmmmm... Perhaps try some different phones.

[@GBOAC]

The technical aspects are clarified from 3:00 onwards. If it doesn't work it means you either wired it incorrectly or you are using ancient (mechanical) telephones which needed higher voltages.