I built an intercom from vintage rotary phones!

We're making an intercom system from two Soviet-era rotary phones (model ТА-68)! This episode also features a visit to the Eliava market in Tbilisi, and a look behind the scenes at Mariam's Computer Repair!
Support us on Patreon with a $3 contribution!
/ workshopnation
Download my schematics for this circuit:
drive.google.c...
Featured tools:
Brymen BM235 Multimeter: amzn.to/3Wk5s22
Ferrule Crimping Tool Kit: amzn.to/3hbu64I
Elenco Hook Up Wire Kit: amzn.to/3DSArYH
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Deoxit contact cleaner: amzn.to/3IO2pIz
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Solder: amzn.to/3GFXAiF
Amtech flux: amzn.to/3DSLbGo
Solder iron tip cleaner: amzn.to/31TjH6w
Production tools:
Sony A7Siii (main camera): amzn.to/3pWAeyM
Samsung S10 Plus (overhead camera): amzn.to/3ET8H7u
Aperture 300D Mk II COB light: amzn.to/3T0B5e8
Sennheiser wireless lav mic: amzn.to/3IK0YuS
C-stand: amzn.to/3GKMfxM
Be sure to check out our retro computing Instagram channel: / circuitlords
Thanks for watching!
#workshopnation #rotaryphones

[@vespaesian]

I’ve been scouring youtube for a video detailing how to build an intercom system using specifically soviet era phones for hours. Finally found this channel and I’m absolutely floored by the production quality. Everything was perfect. When I saw the number of subscribers I was shocked. I fully expected to see several million. This channel deserves far more recognition. Thank you so much for all the information. I’ll be watching on repeat till I finish my own!

[@ThomasBurns]

Thank you so much for watching! Let me know how the build goes, or if you have more questions!

[@Nevir202]

What on earth inspired you to do such a thing in the first place? I mean two people doing that same thing isn't THAT many, but still strange that something so obscure came up twice...

[@borninator]

My sentiments exactly. I can't reconcile the quality with the subscriber count. So grateful that Tom Scott's newsletter led me here. This is amazing.

[@ThomasBurns]

@@borninator Thanks so much for watching, Örn!

[@borninator]

@@ThomasBurns No, thank you! It pleases me so much to watch these types of videos. And thanking me with my name even, accents included! Real classy and makes me feel special. A question regarding the build, did you consider an on/off time for the AC ringing to stimulate the type of ring used by the telephone system?

[@ezyto]

sometimes the youtube algorithm does good things like recommending this channel, just awesome

[@_Ben_T]

Loving the production quality.

[@ThomasBurns]

Thank you, Bekar!

[@benmaxinm]

Absolutely amazing. Looks like Netflix documentary.

[@santyias87]

This channel is a goldmine. I'm so glad I clicked on the link on twitter. Teaches a lot abt tech and life in a beautiful way! Look forward to seeing all your videos!

[@ThomasBurns]

Thank you so much for watching, and for your support!

[@anubhavpanda06]

Rather than being technical and dirty nerdy, you videos are so wholesome and full of life nerdy. I love them. Thank you so much sir 🙏🏼.

[@ThomasBurns]

Thank you, Anubhav!

[@rts9862]

Beautiful video! What a wonderful project!!! It was such a pleasure getting to spend 15-20 minutes with you Thomas, as well as "meeting" your beautiful family!!! I truly enjoyed this project and seeing your passion for every facet therein, Thank You !!!

[@ThomasBurns]

Thank you so much for watching!

[@choppergirl]

My uncle had an old mechanical exchange up in the attic, that he wired all the house phones into, so you could dial an extension and ring any other rotary phone in the house. 1 for ground level, 2 for second floor, 3 for the attic third floor. If you were up in the attic and someone operated it, you could see all the rotary actions move on the mechanics to connect the call and disconnect it. And of course you could dial out on the single house line or two. So you are missing that critical part to connec them all, some mechanical exchange. By the time I got around to setting up my own similiar system, it was the 90's, and you could buy something called the RingRite which would allow 2 or 3 phone lines to share the same line, and with the multi ring tone service from the phone company, the RingRite box would capture the first ring, and depending on the ring pattern from the phone company, route the call to the right phone and subsequent rings would be heard on that phone. So basically with one phone line, you could have 3 different numbers with 3 different ring patterns, and the box would capture it and route it to the right phone in your house so everyone could have their own telephone number and never have to get called to the phone somewhere else... but still only pay for one telephone line.

[@ThomasBurns]

Oooh this is cool! That would have been a simpler solution. But not as fun to set up. :)

[@MegaSuperCritic]

I am SO excited to watch all your existing and future content. Came over from the friendly CRT robot build. Incredible!!!

[@ThomasBurns]

Thanks so much for hanging around, and for the words of support!

[@yeraye.falcon2709]

First video of yours that I watch and I'm already addicted. I'm not a techie myself, but the quality of the production and the stories you tell are engaging. I'm looking forward for more!

[@ThomasBurns]

Thank you, Yeray!

[@mcabzas]

Thomas, this video’s got it all! Engaging! Great work.

[@ThomasBurns]

Thank you, Michelle! My kingdom for an editor like you. :)

[@analogMensch]

That's farly one of the easiest way to connect two phones including ringing :) I also run some vintage rotary dial phones here at home (german W28 and FeTAp 611), but they are connected to an ond PBX, which is connected to a VOIP adapter, so I can use these phones to make calls to the outside world :) I think the problem you have with the connectors for the phones is, that they short out the upper connections on the phones on your circuit diagram. The capacitors are there to block DC current running to the relay and let AC current for ringing pass through. If you put both upper connections on the sleeve of the jacks, they short out and bypass the capacitors, so DC current can run from on side to the other. So if you pick up one phone, the relay of the other phone also will close and disconnect the ringing. Solutions for this are isolating the jacks (as yu did) or putting the positive side of the DC to the sleeve (positive ground). If you want to build this with a microcontroller, you can also use an series inline relay with DC on the phone. If you dial a number, the relay should flicker. You can sense series relay that's on for a certain amount of time as a picked up phone, and each short pulse on the relay as a number count. a certain amount of downtime on the relay can be detects as hung up phone. On german phones pulse dialing was 40/60ms per number, so I think I would try around 350ms for pick up/hung up and everything below 150ms for number pulsing.

[@ichbinilya]

love the chandelier subplot

[@ThomasBurns]

Thank you, Ilya!

[@itsmehans8056]

Saya dari Indonesia, saya harap channel ini bisa berkembang dengan sangat cepat🤲 Kualitas produksi konten, materi, dan informasi yang disampaikan sangat luar biasa. Saya melihat channel DIY besar lain dengan kualitas di bawah anda, sangat mudah untuk melampaui mereka💪💪

[@su30mk30]

Hello. Thank you for such a fun video. That was my childhood dream, unfortunately, I had no knowledge or resources to do so. Maybe I will do it now. I remember when I saw an advertisement you were looking for old Soviet electronics to repair, I thought it was a kind of scam and someone was looking for electronics just for the gold scrapping. I am so glad I was wrong and you bring a second life to those devices.

[@ThomasBurns]

Thanks so much for watching!

[@d1g1taljedi]

I'm gobsmacked by the production quality of your videos! After watching tech videos on KZbin for years, I'm almost unsure what to do by not being segued to the sponsor and not hearing the same 12 soundtracks they all use. THANK YOU for your thoughtful, unique projects, tone and especially what I can only describe as a cinematic quality so severely lacking on most of KZbin, particularly in the tech informational/educational realm. You have a new fan and I hope you get many, MANY MORE.

[@ThomasBurns]

Thank you so much for watching, and for the kind words of support!

[@wildedaveable]

Loved the video. Especially loved the end with your chandelier and friends as you spoke of in the beginning of the video, beautiful and touching. Well Done!

[@ThomasBurns]

Thank so much for watching, and for the kind words!

[@-Nobody-1]

As a radio guy my initial reaction is just use radio waves… but i really like this land line style intercom system. Its just cool… maybe cooler than a radio technology version….

[@ninomartinenko2071]

This was so much fun, missed my city streets driving down to Eliava 😁 loved it, interesting and entertaining, Loved seeing Khatuna and the kids too 😍

[@ThomasBurns]

Thank you for watching, Nino!

[@JohnMassaglia]

Having access to a big electronics market like that would be so fun! Thanks for the video.

[@ckovalev]

What an epic! Fantastic project, Thomas. And really well shot/edited, too!

[@avick718]

8:45 Twisting the stranded wire before crimping the terminal often leads to the wire falling out of the terminal. The wire is simply unscrewed from the sleeve. Crimp only the straight wire!

[@ThomasBurns]

Ah good tip-thank you!

[@belabertalan]

Great video and project. That large transformer looks so cool, it would deserve a transparent acrylic enclosure.

[@ThomasBurns]

A clear acrylic enclosure would have been so cool! But given the weight, it would have to be thick acrylic. Thanks for watching, Béla!

[@davidcasanova5820]

What the fuck, this is at the level of stuff made here, practical engineering, etc, The quality, music, narrative, heck its even super interesting! KZbin recommend this Channel more and let him grow! Saludos from Spain❤

[@ThomasBurns]

Thank you, David! ¡Viva España!

[@Hackvlog]

The other day I was watching phone related videos, thinking about different ways I could use an old rotary phone in this day and age. I am glad I stumbled upon this video. Project as interesting, storytelling was relaxed and enjoyable, describing what you are doing in very natural way, as if we were there following your work in person. Then I watched rest of your videos and they were just as great! Excited to see what you come up with next. Good luck with all the things new job and moving brings to your life!

[@ThomasBurns]

Thank you, Hugatry! Working on the next version of the Alexatron robot now!

[@NoodleFlame]

My dad did this for my sister and I when we were younger, fun times. We could talk to each other from our bedrooms for hours on end without having to go into each other rooms, the things parents will do to stop their kids getting out of bed 😁 edit: ours were also very crackly but it just added to the experience!

[@ThomasBurns]

The true test of any cool tech should be whether children like it. :)

[@Nyymi85]

Absolutely inspiring and stunning project. The atmosphere and feeling in your videos are superb!

[@ThomasBurns]

Thanks so much for watching, Vapaamies!

[@kd1841]

I tried to make a similar intercom system with my kids as part of a Homeschool project. However, I only had a page or two of poorly written instructions and the project flopped. Back then KZbin was mostly cat videos, so I never used it as a school resource. Oh how I wish this video existed long ago. Oh well, nothing stopping me from trying to still make one for myself. 😂 awesome video! ❤from Texas!

[@ThomasBurns]

Thank you, KD!

[@haom95]

Great project!!!!! When I was young (probably you just surround the 50's too), I dreamed with this project. Until I went to the university to study Electronics Engineering, I faced this challenge. But I did with key telephones, using audio transformers and I felt great, when felt the ring sound.. But your project is harder, because this rotary phones needs those heavy transformers... Awesome project!!!!

[@ThomasBurns]

Thank you, Hector!

[@slblackmamba]

I just watched every single one of your videos and i can't imagine a how perfect your contents are. In every aspect , your videos are crazy good. Content , editting , story telling and everything is just perfect. Hope to see more from you in near future. Thanks for sharing your knowledge with us. God bless 😍

[@-Nobody-1]

I like the wiring crimping ferrules… always just tinned the wire, but this is a little more “finished” not sure how else to put it.

[@ThomasBurns]

@@-Nobody-1 I have to say that ferrules have really changed by electronics game. They are just a much more elegant solution than twisted bare wire. For low voltage electronics I went ahead and ordered a bunch of tiny 26AWG ferrules, as these never come standard with the ferrule assortment kits. Thanks so much for watching!

[@mikefitzryk1871]

Nice analysis of how to make it work

[@ThomasBurns]

Thanks for watching, Mike!

[@waynestewart1919]

Thank you for sharing that journey. I really enjoyed the simplicity and the retro phones used in this project. I pray God's blessings on your computer shop. Something I would love to have one day.

[@grumblepus]

You should add a momentary button to control the ring after picking up the handset, like a mine phone. That way if one gets knocked off the hook the other isn't ringing incessantly until you can hang up the other. Fantastic build! I have casually considered something like this and I love how simple your system is.

[@ThomasBurns]

Thank you, Aaron!

[@alyahewich3062]

Уже соскучился! У вас так мало видео... )) а вообще, очень интересная и полезная идея для частного дома. Спасибо и будьте здоровы!

[@ThomasBurns]

Спасибо что посмотрели!

[@dylancoppard9733]

By far the best video editing on KZbin. Worthy of big production companies

[@ThomasBurns]

Wow! Thanks for the kind words, Dylan!

[@ericapelz260]

Beautiful work, both he electronics and the production. Here in the States, we called this a "ring down" circuit; they were typical for field communications at football games.

[@ThomasBurns]

Thanks for watching, Erica! And for the kind words. :)

[@James.Bondsai]

Great video Thomas! Absolute joy to watch, and really cool that you made it work!

[@ThomasBurns]

Thank you!

[@Electroarc24]

Sir... You are so professional when it comes to making videos 😉

[@ThomasBurns]

Thanks so much for watching!

[@Electroarc24]

I'm watching it from Bangladesh....

[@isobelcockerell9068]

Proud of you Thomas!

[@ThomasBurns]

Thank you, Isobel!

[@cameronweston1762]

Those phones are likely using analog microphones; causing the crackling you hear. Analog microphones use loose carbon granules and tended to shift while the handset is used, this causes the crackling sounds. It could also be static electricity within the phone itself too. Phones are so fun!!!

[@go-ig1sh]

Wow! Thanks for your work

[@ThomasBurns]

Thanks so much for watching!

[@progexmagzweihander7124]

fun build, thanks for the video

[@ThomasBurns]

Thanks so much for watching!

[@ElenGlazova]

What a wonderful episode Thomas! Amazingly shot, pleasure to watch🙌🏻

[@ThomasBurns]

Thank you, Elen!

[@eastmolman]

On the old pre rotary phones the ringer uses DC.

[@tscomponents33]

This video, and channel, are great and it needs more views and subs. Glad I found it.

[@ThomasBurns]

Thanks for watching!

[@user-qg8if8sz7s]

I love your explanations, you make them easy and fun to follow along for beginners

[@ThomasBurns]

Thank you, Benedict!

[@martynehook590]

I love this so much, you're telling about five stories at once and the production is funny, technical, detailed, touching and just wonderful. I really hope you have zillions of subscribers soon, never more deserved!

[@ThomasBurns]

Thanks so much!

[@markpirola8152]

Thanks for the passion and simple repurposing of these old phones. On the schematics and metal enclosure I trust you added a nice solid earthing wire to both upper and lower lids. Also a good idea to minimise the 240 AC wiring by having the fuse and switch near the inputs to the transformers where possible. Add additional insulation over any exposed 240v.

[@amircogs]

Beautiful!!

[@RaspduinoUno]

Excellent work. Amazing video production quality as well. Well done!

[@khatunamikautadze6082]

Great job!

[@ThomasBurns]

Thank you, Khatuna!

[@kaueeuripedes9482]

man i`m realy facinated with the project and the production of your content, everything is amazing, congrats!

[@ThomasBurns]

Thank you, Kaue!

[@UnwelcomeGuestVideos]

Yes yes yes yes yes. Absolutely love the use of these. Very clever AC/DC switching system.

[@ThomasBurns]

Thank you!

[@belaoxmyx298]

I really like the way it’s produced and how he uses recycled parts

[@ThomasBurns]

Thank you, Bela!

[@dheofugado2117]

I love all the choice of songs, now a subscriber. Kudos!

[@I000I]

5:23 - at first i thought it would be "ave Maria"! 😁 Astonishing videos you made! Those phones, chandelier, but also people and this market. Music and production. Really enjoying it! Total gem!

[@ThomasBurns]

Thanks so much for watching, and for the comment!

[@Frank-Y]

You must have a big team making this kind of video quality.

[@ThomasBurns]

Hahaha I wish! I do have a few very talented friends who are cameramen and camerawomen, and they've been very generous with their time. I couldn't have done it without them!

[@abrahamshabatee4384]

Super cool ☎️ project ❤ Thank you for sharing kind sir.

[@krussell__sprouts]

SO thrilled to find this! I want to build something similar for an art piece I'm working on but have a question for you Thomas! What happens if the other person doesn't pick up after the rings stop? I want to setup the intercoms in more of a walkie-talkie or voicemail recording way. Where essentially someone calls the other phone and if there's no answer, they can just continue talking and leave a message or live transmission that will play through the other phone. So that if/when another person does pick it up they could they engage. Does that make sense? Ideally, it's like leaving a voicemail for a stranger and at any point they could decide to pickup and engage. So trying to figure out tech-wise how to build this :D

[@ThomasBurns]

@@krussell__sprouts I don’t have a specific answer for you, unfortunately, but my gut tells me that a basic version of the system you describe could be built around a microcontroller. It wouldn’t be very intelligent, but it might accomplish what you’re after. :)

[@BreathingAir]

Refreshing to see a channel without built-in paid sponsor reads.

[@RafaelCardoso299]

I get lost with the technical part , but these videos are mesmerizing to watch ! Such well done video and amazing craftsmanship. Keep rocking !!!!!!!!!

[@ThomasBurns]

Thank you, Rafael!

[@weirdARAB.]

Love the style of his videos

[@KyleBevis-u7j]

Your channel is amazing! I’m annoyed KZbin didn’t suggest it sooner. I’m burning through all your videos ❤

[@ajithd19]

The days of instant and fast content, I love your content it shows you are your passion in people and technology ❤🎉

[@honda86tb]

Just found my new favorite channel

[@ThomasBurns]

Thank you so much, Terry!

[@optroncordian7863]

Another self retaining relay, activated when both phones are picked up, which temporarily turns off the AC current. It must disengage when both phones are hug up. The idea is to not have any phone ringing when hanging the other up. You need the AC only at the beginning ...

[@ThomasBurns]

That’s a great idea! Thanks for watching, Optron!

[@bekabeka4969]

Would be cool built small Step by step telephone exchange, because in Georgia still doesn't exist telephone exchange museum.

[@ThomasBurns]

That’s a great idea, Beka!

[@bekabeka4969]

​@@ThomasBurns I'm looking for telephone lovers that do it together 🙂

[@NicolasMaton]

Your channel is a gem everyone should discover

[@ThomasBurns]

Thank you, Nicolas!

[@sepitbeats]

what a fun journey

[@cedricwilford]

Really well done. Subscribed.

[@ThomasBurns]

Thanks so much, Cedric!

[@mohamedchikhaoui2463]

Such great videos. Your projects are so much fun and the production quality is pretty unmatched on KZbin. And also, a wonderful family that you've got. Hope the best for you guys

[@ThomasBurns]

Thank you, Mohamed!

[@gregkara427]

you are gonna make me cry bro, i was born in neighboring Armenia (live in the US now) and i completely understand the courtyard vibes, keep up the great work.

[@weraarchanon3486]

It's great. I love your project. It's incredible but you can do it. Thank you for this video.

[@ThomasBurns]

Thank you for watching, Wera!

[@WriteSign]

I like the bulky-ness! I'd stick it on the wall with pride. Can it be done like a hotel com system where you can press a button and ring an individual phone? Like for 4 to 8 handsets maybe? That would be exactly what I'm looking for. I've been steadily going deaf for a while now and I got these awesome rotary phones with a red blinking light on top (I'll need two more still) that I want to hook up in all the rooms of my house so I can blink the kids and tell them I want them to come help me with something (yes people, deaf doesn't mean I can't speak anymore LOL). There are some deaf aid things like it, but it is basic tech and should NOT cost an arm, a leg, a pint of blood, and your first born for crying out loud! Also they are ugly as sin, without even a fraction of the cool metal & retro look you've created. They are more like cheap, plastic junk that never caught up with modern tech (which are trying hard to prove that Deaf lives Don't matter). Maybe it could have a cool toggle switch wall panel to ring each phone! I would colour code them and all 💗💖

[@pavlosslavinskyi4871]

First of all respect for the technical aspect it's awesome. Production quality of the million subs channel. Secondly, I always respect Georgian people.

[@ThomasBurns]

Thank you, Pavlos!

[@davidspencer7718]

Super cool.

[@ThomasBurns]

@@davidspencer7718 Thanks for watching, David!

[@dtriplett03]

1:00 We(You) put the Able in Feasible 😅❤

[@javierdelatorrecohen784]

Thomas, I found out about your work from the robot friendly video and now you have another fan, this time from Los Angeles, California USA. I love every part of your videos, but my favorite is when you express frustration with your "argh"... :-)

[@ThomasBurns]

Thank you, Javier!

[@stephenjohnson5380]

very enjoyable and interesting Thomas!

[@ThomasBurns]

Thank you, Steve!

[@harrison2025]

Really glad i found your channel. Its a wonderful place to nerd out and your filming/editing is really well done. Please, keep it up!!

[@4business-englishrundown]

Very cool video! Enjoyed watching!

[@ThomasBurns]

Thank you!

[@vijithviswambharan775]

Sir, why didn't you think about manually winding a transformer for the desired voltage?? I've met the same connector problem while assembling an audio amplifier. after an hour of struggle I realised why most of the audio amplifier systems use the "Push Release Connector Plate module" at the back as speaker terminal, no grounding problem... Really I loved your video... and i felt like I am watching it somewhere i love to be, other than my table. Thanks for filming this journey ❤️

[@ThomasBurns]

Thank you, Vijith! Doing a custom winding on a transformer sounds cool, but that’s a bit beyond my skill set, I’m afraid. :) thanks so much for watching!

[@akshay-ashok]

So glad I found this channel.

[@NoBug404]

Looks like a lovely space to be in.

[@Harquimm]

I wish that this intercom system was available for order online.

[@BurkenProductions]

13:00 This is why you never use steel cases and always plastic, especially when having large transformers and stuff in them and mains power.

[@liltr3w339]

I am not sure how but you became my favourite channel on yt. Actually i know why but this is hard to describe, like i have personal connection with you and your videos, something like your goals are mine as well and when i am watching i get the feeling like we have achieved the result together even i have not moved my ass of my chair :D

[@ThomasBurns]

Thank you so much! This really means a lot to me. :)

[@p-niel5328]

I am a new subscriber here. I am happy that I found another YT Channel whose contents are interesting.

[@ThomasBurns]

Thank you, and welcome!

[@johnterry8890]

Greetings from Texas, USA! Loving this channel. Awesome content. Thank you for sharing your work. I’m positive you will have millions of subs in the future! Have. A great day

[@ThomasBurns]

Thank you, John!

[@taiwodamilola8622]

Thanks

[@FabioEnrico100]

Wow I am really impressed about the quality of your videos! Good job!

[@ThomasBurns]

Thank you, Fabio!

[@X862go]

good job man!

[@antonygreenup]

Your channel is EXCELLENT. THANK YOU SO MUCH.

[@ThomasBurns]

Thanks for watching, Antony!

[@rickyroy8900]

Subscribed within 2 minutes into the video

[@ThomasBurns]

Thanks so much, Ricky!

[@l3chevalier]

This looks awesome! Nice simple invention, this is the second video I watch (watching it on lunch breaks), I don't want to watch more than 1 a day because I don't want it to end. This channel is amazing ❤🎉 very happy to have this suggested for me, I came up when watching a Adrian Digital Basement episode. Same vibe, but not so much only on computers.

[@ThomasBurns]

Thanks so much!

[@codingwithtd5196]

Love the videos you are doing. Thanks.

[@ThomasBurns]

Thank you, TD!

[@jack_fm2751]

This channel is everything I need

[@ThomasBurns]

Thank you, Jack!

[@cdoublejj]

after your grounding issue, that is well made beautiful box. artfully done. EDIT: lolol you mean the Trashcan droid!?

[@ThomasBurns]

Thank you!

[@Subgunman]

That is odd that a rotary phone can’t be used on modern networks. In the States where we have state of the art switches that can still support dial pulse however the REN of these phones is the optimal 1. This amounts to how much current is needed to run the ringer. This amounts to a high current. New phones need very little current to ring electronic ringers. Ringing current is now generated in the fiber to copper DSLAMS located in each neighborhood. They don’t have the access to the high current ringer systems that were once in the central office. That red phone reminds me of the EXETER Line of phones of the 70’s-80’s Bell system in the States. Quick question, are you an ex pat living in Tbilisi? Your English is perfect.

[@TheRealKlinky]

Just buy a soho pabx box & run many phones throughout your home/office with individual extensions...but I do like the old school phone!