keep an eye on my socials over the coming month as ill be listing some things for sale that haven't made it into the museum inventory to help fund future projects as i have currently overtaken the beans on toast budget! so keep your eyes peeled, eurorack modules etc. also Malcolm has other racks for sale so check ebay or strowger groups online. you'll find him!
@@sssstarboardvenus the next one is a big job. im on the final prototype its a sequencer keyboard and its taken a couple of months to figure out! unfortunately! as last year the modules were relatively simple the ones this year are a tad more involved and are taking a bit more time to develop! give it 3 weeks for the sequencer i recon. im working my hardest :)
Doode !!! Im thinking you need a Doctor. And BTW cleaning the crud off the switches is one of my specialties. I cant beleive you get as wound up and excited over this stuff as i do !!!!! Seriously can i come over and help you with this thing???
It's actually a human super power... I know a few people that are that manic and focused. These types of people took us to the moon. Now, if he could just get interested in solving world peace!
Last week I saw a documentary on communication in eastern Europe (the main focus were subscribers telling their life stories to service engineers, so not all that centred around the technical aspects) and apparently some countries still used electro-mechanical exchanges as of 2020!
Its a phone board layout.. you have station lines that tie to co lines from the dmarc and from the stations youd have some kind of directory like startalk where you jump through incoming calls if were using it as an operators phone director deal or youd have them sit in a que sort of where it picks through the available lines and uses the nect free one automatically with its relays which are actually unique things with a strip of contacts that it chugs through . Sounds like a big ass typewriter when its in use.. with some dings and buzzes and a bunch of chugga chugga clicky clicky…. And every now and again youd get a shitty contact that would hang open and make a brrrrr sound until it popped back into rotation.. hard to explain, especially since ive been away from that kinda thing for a good 10 years st least,. Worked more on t1 lines and basic analog blocks for 911 and did a lot with a pbx.. was a shitty part of my life but pretty much the whole things been shitty so i guess no reason to forget about any of it.. damn i need a good hollow point pain killer….
@Common Raccoon I had to lace the wiring looms for similar machines. One job required me to build a loom as large as our car park... I had to make it in the car park itself. I had it all to myself :)
Long term project: Wire in all the "noise" making equipment in the museum and you can dial to each of them with multiple phones. You get the phone-busy sound if the device is off. :-)
That would be so cool, you could have a list of 'noise numbers' next to the phone. It would also be fun to use it to start looking for the device actually making that weird noise in the museum after hearing it on the phone. I think that would be a great way to explore the museum.
omg that would be soo cool! I was thinking just put together some very simple synths that can be called, but using the existing ones in the musem would be SO much cooler!
What if I could actually call the museum from an outside line, and then pick a specific noise number, like an extension. Maybe like internet radio? Id be cool to actually give each museum piece its own phone number. Thats a lot of work O.O
get 50 old school 80's BT phones.... change the bell ringers in them to a piano scale so c c sharp d d sharp ect over 50 notes..... one big ass BT megaphone... :D
I was about to suggest that, at least where i live one can sometimes get them for free. There where also those extra bells one could connect to the incoming telephone line for elders with hearing disability and other people that where basicaly the ring signal mecanism only, i think those are probably also scrapped now when theu are cutting the copperline, i remember i installed one of those for grandma long time ago.
This brings back memories. In my last year of school an old 50-line PBX turned up in the physics lab. They let me have a go at trying to get it to work. I mostly succeeded, but it was missing the motor thing at the bottom that produced the tones and ringing current, so I had to bodge something up to replace it. I can't remember exactly what I did about that. I do remember connecting four 12V lab power supplies in series to power the whole thing. Fun times!
Basically it's a rotary converter that turns 50 Hz mains AC into various frequencies and interrupts them using rotating cam switches, so I suppose you could use all kinds of solid-state replacements that generate things like your dial tone, busy tone, ring tone etc. It wouldn't quite sound right though, because those converters were quite audibly analogue and electro-mechanical.
Create a twitter interface... People stand in front of it and tweet the number they want it to dial and they watch it do it's spiny clicky thing... find the tweets by a hashtag and there's some ongoing publicity...
I started my career working on equipment like this. Seeing how excited you are Sam at getting your hands on this kit reminds me how boring and non engaging some of the modern tech had become, even if it is very powerful. Good luck with your restore mate!
Still have my wire wrap tools. I went into the telecom industry when those things were being replaced with digital switches (circuit boards) and now they are the size of a desktop pc if not smaller. I can still remember how loud and big the switch rooms were.
One reason shorting across the power bars might take the end off your spanner was that a typical exchange would have an almighty 50v backup battery connected that would keep the exchange, and the emergency calls that use it, running perhaps for days through a major mains power outage.
Exchanges batteries (2 off) were originally specked to support the exchange for 24 hours with back up generators to support them beyond that. In the later years of strowger, it was accepted that due to the increased traffic volumes, the batteries would only be needed to support the exchanges for 1 hour before the generators were fired up. In practice, the battery support was probably somewhere between the 1 hr and 24 hr requirements depending on the size of the mult and the time of day. The batteries themselves each had 24 individual lead acid cells, and in the bigger exchanges each cell was an open top box roughly 40” high, 40” deep and 24” wide. Laid across the top of the plates (run width ways) of each cell where two pieces of plat glass (run lengthways) at 45* so that they formed a gully so that the engineer could pour the sulphuric acid without too much splash back. The batteries were ‘floated’ across the power input from the rectifies to provide smoothing to the incoming current. Each exchange unit had two of everything in the power room, so two rectifiers, two batteries and two standby generators. The city centre central telephone exchange I worked in had a Strowger local (mostly 2000 type, but some pre 2000) a crossbar local (type 3) and a TXE4 local as well as a Strowger trunk, a telex exchange two manual boards and a repeater station. So that was 8 power set ups each separate (although some of the older stuff shared the same power rooms. The sysX and sysY exchanges that replaced most of that each had their own power cupboards and were no where near as exciting.
@@captbeardy Thanks captain, great detail. I was a signal and telecom department trainee for British Rail in the 1980s and the internal phone system still had many small strowger exchanges working at the time. My training involved placements with tech teams for both signalling and comms, and at the end of it I chose to go into the signalling side of the organisation, but I was pleased to have seen this classic tech still in action towards the end of its life. Railway signalling at the time was still mostly relay-based, although processor-based systems were just around the corner.
@@stephenw2992 that’s certainly a tale I was told by the ‘old boys’ I worked with in the Strowger exchanges. I can’t verify it as true, but looking at the size of the exchange main buzz bars and the fact that in the older parts neither the earth or the 50v bars were insulated (though the 50v was painted red) I can certainly believe it possible. I’ve heard other tails of daring do and misadventure in power rooms, and even seen the evidence of one or two, but people do like to exaggerate 😁 And then of course there’s the Christmas we set up a bar in one of the CTE battery rooms supplied by one of our number who was also the chairman of a local rugby club. Ah, nostalgia is not what it used to be.
I'm in Canada, and took a huge interest in the old school telephone network once I started contracting for the phone company 15 years ago. They still have some vintage equipment abandoned in place in most older CO's. I've taken many pics & videos over the years. The outside plant has been hanging by a thread, and many areas still have the same cables and terminals from the mid-60s. I had been in contact with a retired phone man who ran their museum, hoping he could give me an official tour, but he got sick and passed a few years ago. Anyway, a couple interesting resources online are the Classic Rotary Phones Forum and Evan Doorbell's phone trip recordings, although they're more focused on North America.
I remember seeing one of these in a (GPO?) surplus store that used to be around/near St. Lukes avenue , Ramsgate, when as a teen in the 1970's we would wander around hoping to find treasures we could afford.
I am from Malta, where telephones ran on Strowger exchanges up to the 90s! I remember seeing one of these exchanges in operation when I was an engineering student at university, around 1993 or so. Very noisy device. One thing I remember which I'm not seeing in yours was automated rotary switches that would search for unused lines. Since the line would be short circuited (on hook) it would have no DC voltage across it, lines with voltage would be skipped. Of course, as the contacts aged more and more live lines would not be detected resulting in crossed lines - one of the wonderful artefacts of the Strowger system. It goes without saying that there was no such thing as call logs, the phone bill was just a count of 'pulses'. Also phone calls had a fixed charge for any length of call - I remember calling my girlfriend in the evening, going to sleep with the phone still off the hook and saying hello to her in the morning. Those were heady days!
You could also use it to dial up which synth you wanted to listen to, and use another line to dial up a MIDI destination to send keyboard data to. Have a station with monitor speakers, a keyboard and a couple of dialers, one for the audio and one for the keyboard, then the correct dialing pair would allow you to play the corresponding keyboard.
Since you first started these Strowger vids I've been picturing a telephone exchange on stage playing Kraftwerk's The Telephone Call. That's my ring tone btw.
This is amazing for, my dad used to be an engineers for BT in the 70’s and 80’s. I used to go on call outs with him the the exchange and the noises of all the calls going through were amazing back then. The are they were kept in was huge like a big gym hall. Now it’s all in like one PC?
@@HBCrigs Thanks! Also, back when I was a bit emo-er and listened to Korn all the time, I called myself the "Twisted Transistor" all the time! Happy pride month~
Excellent flags 👍 and cool dragon sona! 😊 (plus obviously neat synth idea - ever since Wendy Carlos blessed this field, us trans women have been drawn to synthesisers!)
your videos are always so interesting. i never know how anything works, but its always so cool to see it all and how you're so knowledgeable about everything
LOL I have the same green phone attached to your exchange, came out of my Nans house in the 80's and an identical black one that was on her extension line upstairs. Dad and Grandad GPO and BT 60 years between them, now I've done 25 years in telecoms. The last working strouger exchange working I believe is in Holborn. Blue, Orange, Green, Brown, Slate, White, Red Blue, Yellow, Violet.
As an apprentice I was tasked with building a battery back-up bank for one of this thing's successors, the System X exchange, in our lab environment. Just as I was connecting the final cable onto the -50v battery terminal the spanner slipped and the other end contacted the frame, which was unearthed. I had been given an uninsulated spanner by the supervisor and as a result there was a loud bang, a flash and when the smoke cleared I could see that one side of the open end of the spanner has welded itself to the frame, but this was no longer connected to the spanner itself as there was a good 5mm of it missing! Those battery banks were rated at 50v / 100 amp continuous and could deliver a lot more than that in a short circuit condition. My supervisor got a proper bollocking and went to one of our other sites to hide for a while! This was all 30 years ago now, happy times.
Mate can't wait to see what you get upto over the next few years . You are a long term investment bro . Your way of multi generationalism and simplifying these complex processes. Your enthusiasm for your craft is awesome too bro . Mate you sound like Neil and look like vyvyan so good bro .
I remember shorting a bus bar whilst working on the top of the rack and the molten bits of my spanner set fire to my mates T'shirt who was standing below me. To think it was only 50v DC but the current load..well!
My mate did that in our exchange.. he was pulling a metal legged chair between the rack and a travelling ladder.. and the leg rubbed off the blue insulation of the bus bar.. and it was also in contact with the frame.. BANG!!.. the chair leg was destroyed.. the rack went very quiet as the 50v fuse had blown.. we rushed round to find him looking white faced. Ha ha ha.. good times…
I wonder if back in the day, the crackling heard over the line while having a phone call was due to this sheer amount of mechanical contacts of relays and switches. I had always thought it was due to the cables outside being moved by the breeze, but seeing such machine changed my mind... I miss those crackling sounds a bit, it added some thrill to the conversation.
You shouldn't be hearing crackling once the call completes unless the contacts are extremely dirty. Other possible sources of the noise are the carrier or radio links between exchanges, or the other party's microphone. You could, however, hear the switch working while you are dialing. Such sounds can be found at evan-doorbell.com
@@user2C47 Johann...I mean Evan and his pals sure got a LOT of historical recordings! I've listened to many of them! He narrated the audiobook version of "Exploding The Phone" by Phil Lapsley. A very interesting character 😁
I can't wait to come see the museum one day! My grandmum lives in England so next time I come to visit I'm going to try and see the museum, hopefully it will be open by then.
I wish you all the best on that project.. they are quite a bit of work I have not worked on anything like that for over 40 years now, if I was not in Australia I would offer to help get it going You will need another power supply telecomms usually use a + earth
I love that I started following you for the DIY synths and we've gone on a journey through starting a museum and now we're into vintage telecommunications 😆 Also, yes! The sounds on my MPC are AMAZING
This is awesome! Thank you so much, I’m also interested in telephones, but will be honest trying to get my head round how the exchange all works together. More telephones exchange videos please!! ☺️😀😀
I remember when I was a kid following along with my dad who worked for the Swedish state telephone department "Televerket" and going into a local switching station. A small house jam packed full of clicking relays. And a few years later when Ericsson released the AXE switchboards the station was empty except for a half full rack tucked into one corner
Remind me of Going to work days with my Bio Dad and going into BT Exchanges back in the 1980s ~ 1989 They Were doing the Analogue to Digital Conversions + Tours of Mercury Rectifiers + Lift Machinery + Backup Generators + Battery Rooms + Transmitters Even taken a Good Few of these Apart due to them being Scrapped
One of my previous job's for plessys in the edge lane Liverpool factory was a assembler and t 2000 switch adjuster great. Times 1969 to 1978 happy days 👍👍😉😉
you could plug tape decks or something to some of the extensions and play music on loops and have a list of numbers and a phone that people can pick up a phone, dial a number and get to hear a song playing and different numbers will play different songs, or synths
There used to be a big Strowger factory on Edge Lane in Liverpool. It ended up as Marconi until that went pop after the management made some very bad decisions in the early 2000s. And now part of it is a Range store and another bit is a Travel Inn.
I used to repair these.. but it was for international telex.. in the city of London.. was 50 volts to drive the equipment.. and 80 volts for the signaling..
A ops B ops CD. :) I spent nearly 40 years on transmission, but if I recall correctly you will only be able to have as many calls in progress as there are linefinders. One linefinder allowed up to 48 subs to access 1 group selector. I think, it was a long time ago.
The Tunny Machine at Bletchley Park (designed to help break the Lorenz Cypher) was based on uni-selectors used by the GPO... Obviously later replaced by valves of Colossus.
In the 1990's the Highlands of Scotland were eventually all turned over to the digital telephone exchanges, and the old exchanges were removed for scrap. But....!!! A local "scrap merchant" packed them in shipping containers and sold them all to India. One of the electrical supply company's substation still has a working version of a single "exchange", as it still has a dial telephone that clicks and whirrs when you make a call, but you can not phone a business with "push button options" to reach a department.!
I wonder if he has seen that Garage 54 Video, where they made horns sound different with air, helium and sulphur-hexaflouride. I think he could make a synthesizer out of that. Just with Gas and no electricity. :D
I wish I was on your side of the pond mate, I would definitely check out the Museum of Everything Else. You're having awesome fun with this old technology man!
Adding piezo microphones into selectors so that they would "listen" to relays and outputting that signal as triggers for modular would be nice. Or maybe whole interface between this and kosmo for dialing numbers or routing cv/gates/audio through it.
Check the history of the Telharnmonium instrument. It might be fun to pick up a telephone in some corner of the museum and dial to any music/noise/tone/muzak producing instrument in another corner.
Can't wait to get a couple friends and a truck so I can move the old Nortel SL1(with Meridian Mail and old HP console for admin stuff) out of a hotel I do work at and into my personal phone museum. It's basically a mini version of the DMS100 that runs many North American phone exchanges and can even use some cards from the DMS. I would love to get the Redcom MDX mechanical switch from a certain exchange in Alaska. I loved the sound of that thing when it was in service.
If you mean an MDX386, I have several shelves working, and they don't make much noise, as with the eception of the line card relays, they are PCM switching.
@@leejgen8754 They have/had a 384 up in Livengood and there used to be a test number you could call that would read off temps, humidity, etc and then let you listen to the room for about 5-10secs....lots of clicky clacky gear in the room. The exchange is still using the old error messages (CBCAD, NIS, etc) they recorded in the room and you can hear the switches in the background. It was also the last exchange in North America to respond to 2600 and bluebox tones.
Hey Sam, have you considered building an adapter/converter that would take an incoming cell signal to trigger the exchange and in turn trigger a sound source of some kind? I could see it being super cool as a guest to the museum if dialing different numbers on my cell phone would trigger, lets say, a sequence on the relay sequencer or a bunch of relays triggering old telephone bells tuned to different pitches. ie. Dial a number on cell, watch the relays do their thing, hear the them from 2001 played on old phones. I wish I had your technical skills. I find this and many of your other projects deeply inspiring.
Now you need a lot of old answering machines with looping tape tracks to patch through that. Either that or a lot of different kinds of various phone ringers. Either way, it's possible to make something interesting result from that thing working.
If you can get two running,set each one up to simulate separate mini exchanges with phones attached to allow demonstrations of a phone on one calling a phone one the other
hey up im just looking through the comments but thats what i ended up doing. i have them boith currently about 10 phones and 10 synths wired in to each. neqw video coming soon check this museum not obsolete youtube channel i chat more about it
I took one of those same systems out of commission in a hospital once.. i played with it.. a lot.. lol.. if you take the power supply and run it to its max power (50v) you can cross some jumpers and they send certain co lines to house lines but since theyre not working ie no ring current then they twitch and buzz like what you hear in the background of old telephone operators sound clips….
Tell you the truth tho i ended up blowing the hell out of it. In that room they had a 480v switchgear and i ran it to the mains when the hospital was dead one night and it friggn looked like some 1980’s scifi movie with it arcing through all the station lines and all.. exploded all the lights and melted a bunch of it.. was fuggn awesome…
😃 When you just bought a giant piece of rusted cumbersome junk and you keep saying "it' not that bad... it's ok... with contact cleaner... it should, etc..." I love such projects!
I’m so glad that what I said a few months ago about how you should buy old telephone equipment to let your phone collection call each other; has come to pass!
the spiral things is called "wire wrap" and it does take a bit of practice but once you get the hang of it really dresses in cable and cross connects. at least they are called wire wrap in America could be different in the UK but would guess it is called the same. Try to find out some one who works in a central office "telecom" near you willing to sell you some older tools they are pricey new or donate some older tools for you because using proper tools makes the world of difference.
You know all those relays, stepping-things, and selectors, are all going to make different percussive sounds. You might even, if you have parts to scrap, rig a couple up to a cymbal or a woodblock or something. And then you'll need a sequencer... which it already has. First Strowger drum machine? It'd be amazing! You could program sequences either with it's many switches, or use the "RAM" that's reified in the selectors, to store 16 steps or so, dialled in on one of those operator console telephones! If you have one... Actually not just a relay, but why not 50 relays? That'd be a unique sound, and get past much of the need for amplifiers, which of course don't exist, the best you'd get would be a carbon microphone. Did you know carbon mics were the original amps on telephone lines, before thermionic valves? Literally a carbon mic, and a magnetic earphone, just like in a phone, mechanically attached as one manufactured unit. Worked cos of the unusual property of the carbon mic as being a variable resistor. So driving one with a higher voltage than comes in to the earphone, gives voltage gain. It'd be great to make a musical instrument from this, and would be in your style. Get a relay to buzz at a few hundred Hz if you wire it up to oscillate, but that wears them fast, there's always a spark between the contacts. Set the frequency with a big cap, and have maybe an octave to play awful low-frequency lo-lo-fi ditties. If you're worried, use brand-new relays you can throw away if they burn out. I would even dare say I'd prefer it as an instrument than as a working exchange. Depending on how many of these units still exist in museums, if there's already plenty, I'd modify it into an instrument. Non-destructively, you'd only be rewiring it, no mechanical changes needed, allowed, or desired. Being able to dial in a sequence like a phone number would be epic! When you're dead, and, still intact, somebody not yet born collects it, they'll think you were a maniac! As an intact original machine, it would put across it's immensity, complexity, and power. Demonstrate how we did things before beige boxes with an Ethernet socket on the back. This is the idea, the formal logic, of a telephone exchange, made into flesh, directly and literal-minded, in electromagnets and metal. "When all you have is a hammer", cos electron beam lithography hadn't been invented yet. But the working principle, the need for it, and a real understanding, comprehension, of what it is and what it does, how and why, most people would not get. You have to know it, to love it properly, and the people who can do that, already do do that. So the masses wouldn't understand it, and the geeks don't need it. So I wouldn't feel guilty about instead wiring it up to a drum machine you could telephone patterns into. Shit, you might connect it to the public network, or even to a cellphone! Ring it up, feed it clicks, pulse dialling, and party like it's 1891! Call in, program it, then hear it clatter and sing down the line through that carbon mic! You could post the phone number here, THAT would be a museum piece!
To be honest I would like to be telephone exchange mad too lol those things are fascinating AF, Lucky for us lol you spend all your money on them and make videos for us to enjoy, Thanks for that Cheers Mate!
There's quite a few people that've done that, look up C*Net & NPSTN, pretty much hobbyist Asterisk/Voip networks that people connect vintage phones and switches to
My dad used to manage the centers the us versions of these was in. Sadly though he has Parkinson’s so I can’t really get much info out of him on these. I remember going into one as a kid. Sounded like a million typewriters going. Then they replaced it with digital in the 80s and it took an eighth the space and just fan humming instead.
Shiesse. Man when I left my last house, I left a toolbox full of armature adjusters, relay spring tensioners, bank cleaners, test probes, original black rubber butt (careful now), feeler guages, home-made 'earth flasher' etc.. Ahh. A bunch of goodness... Oh yes.. Busbars - NEVER short a busbar. I saw one being vapourised once.. Wasn't much of the spanner left.
If anyone can make this work again it's you. I know nothing about step office equipment. I used to work for Nortel and did DMS switch installs and testing.
I LOVE relais anyway so this telephone exchange obsession of yours is just awesome to watch. I'm so curious to see what will eventually come from it. Knowing you, it'll be something worth waiting for :D ^____^
If the issue of world hunger was an antiquated machine from the 1960s you'd have the Earth fed before July rolls around. There would also be really cool bleeps, bloops, and clicks. I do expect sample packs of every individual mechanical sound these things make, naturally.
Great now you have a system you can fiddle around with, AS it just is a automatic connection system you can indeed make music with it in 2 way's. 1 just the mechanic sound of calling and stepping etc. 2nd the connections it self. Just disconnect the tone dayno. Now you only have the 48Vdc line voltage to deal with. Series capacitor to get rid of that (see old phones thought 4uF or 8uF) to keep the line open you need the coil. The system it self should be around 600 Ohms. So you simulate a phone dial, pick-up and disconnect then you can select all kinds of "phone numbers" to select sounds etc. You can then use it as a big sound selector though dailing numbers. But the limitation is lines. It is a 1 to 1 connection system. Then the system can f.i. only handle X-times lines. Think you can from 1 dailing side throug capacitors connect that to 1 input. or 1 output. Automatic dailing can be achieved with relais and some cpu boards. Would be a great project. Wow. Normaly phones work in the range 300-3400Hz. But if you use right coils and capacitors you can reach the whole range. You don't have to deal with phone line amps,long lines, PWM systems to step up to other districs, How ever in this tempo you have your own telephone exchange company soon.LoL.
keep an eye on my socials over the coming month as ill be listing some things for sale that haven't made it into the museum inventory to help fund future projects as i have currently overtaken the beans on toast budget! so keep your eyes peeled, eurorack modules etc.
also Malcolm has other racks for sale so check ebay or strowger groups online. you'll find him!
Hey Sam, when comes June's module for the module a month?
@@sssstarboardvenus the next one is a big job. im on the final prototype its a sequencer keyboard and its taken a couple of months to figure out! unfortunately! as last year the modules were relatively simple the ones this year are a tad more involved and are taking a bit more time to develop! give it 3 weeks for the sequencer i recon. im working my hardest :)
@@LOOKMUMNOCOMPUTER sounds good, can't wait to visit the museum when it's open!😀
I’d help!!
Doode !!! Im thinking you need a Doctor. And BTW cleaning the crud off the switches is one of my specialties. I cant beleive you get as wound up and excited over this stuff as i do !!!!! Seriously can i come over and help you with this thing???
If I had a 10th of this man's energy....
It's actually a human super power... I know a few people that are that manic and focused. These types of people took us to the moon. Now, if he could just get interested in solving world peace!
The old spiral things are 'wire wrap' connections made with a specialized tool, the wire wrap tool.
It's a very cheap and obtainable tool.
was just about to say the same thing. they're a bugger to use.
I started in telecommunications working on these things. A busy telephone exchange was a noisy place.
Last week I saw a documentary on communication in eastern Europe (the main focus were subscribers telling their life stories to service engineers, so not all that centred around the technical aspects) and apparently some countries still used electro-mechanical exchanges as of 2020!
I worked on international telex Strowger .. very noisy.. no ear protection..
i used to hand solder those boards at siemens in the late 80's till the mid 90's....
Hehe....siemans
Its a phone board layout.. you have station lines that tie to co lines from the dmarc and from the stations youd have some kind of directory like startalk where you jump through incoming calls if were using it as an operators phone director deal or youd have them sit in a que sort of where it picks through the available lines and uses the nect free one automatically with its relays which are actually unique things with a strip of contacts that it chugs through . Sounds like a big ass typewriter when its in use.. with some dings and buzzes and a bunch of chugga chugga clicky clicky…. And every now and again youd get a shitty contact that would hang open and make a brrrrr sound until it popped back into rotation.. hard to explain, especially since ive been away from that kinda thing for a good 10 years st least,. Worked more on t1 lines and basic analog blocks for 911 and did a lot with a pbx.. was a shitty part of my life but pretty much the whole things been shitty so i guess no reason to forget about any of it.. damn i need a good hollow point pain killer….
@Common Raccoon I had to lace the wiring looms for similar machines. One job required me to build a loom as large as our car park... I had to make it in the car park itself. I had it all to myself :)
Long term project:
Wire in all the "noise" making equipment in the museum and you can dial to each of them with multiple phones. You get the phone-busy sound if the device is off. :-)
That would be so cool, you could have a list of 'noise numbers' next to the phone. It would also be fun to use it to start looking for the device actually making that weird noise in the museum after hearing it on the phone. I think that would be a great way to explore the museum.
omg that would be soo cool!
I was thinking just put together some very simple synths that can be called, but using the existing ones in the musem would be SO much cooler!
brilliant idea, really
What if I could actually call the museum from an outside line, and then pick a specific noise number, like an extension. Maybe like internet radio? Id be cool to actually give each museum piece its own phone number. Thats a lot of work O.O
Or get himself a GPO 1960 switchboard, with pulleys inside and plugs and sockets lines outside connecting to his newly built exchange.
You've heard of the BBC radiophonic workshop. Next up is the LMNC telephonic workshop! ;)
hahaa yeah pretty much!!! squeezing out rhythms from this thing
get 50 old school 80's BT phones.... change the bell ringers in them to a piano scale so c c sharp d d sharp ect over 50 notes..... one big ass BT megaphone... :D
amazing idea hopefully sam gets around to this
I was about to suggest that, at least where i live one can sometimes get them for free.
There where also those extra bells one could connect to the incoming telephone line for elders with hearing disability and other people that where basicaly the ring signal mecanism only, i think those are probably also scrapped now when theu are cutting the copperline, i remember i installed one of those for grandma long time ago.
The Strowger is one of my all time fave electro-mechanical machines. I see the one in Bletchley Park every so often and it's just a marvel.
This brings back memories. In my last year of school an old 50-line PBX turned up in the physics lab. They let me have a go at trying to get it to work. I mostly succeeded, but it was missing the motor thing at the bottom that produced the tones and ringing current, so I had to bodge something up to replace it. I can't remember exactly what I did about that. I do remember connecting four 12V lab power supplies in series to power the whole thing. Fun times!
Basically it's a rotary converter that turns 50 Hz mains AC into various frequencies and interrupts them using rotating cam switches, so I suppose you could use all kinds of solid-state replacements that generate things like your dial tone, busy tone, ring tone etc. It wouldn't quite sound right though, because those converters were quite audibly analogue and electro-mechanical.
Create a twitter interface... People stand in front of it and tweet the number they want it to dial and they watch it do it's spiny clicky thing... find the tweets by a hashtag and there's some ongoing publicity...
I started my career working on equipment like this. Seeing how excited you are Sam at getting your hands on this kit reminds me how boring and non engaging some of the modern tech had become, even if it is very powerful. Good luck with your restore mate!
You dont know if there are still any of this equiptment hiding in old exhchanges that never got removed do you ?
I used to work on these in 1976. Wiring a loom was fun, getting it to look good was almost as important as making it work
Still have my wire wrap tools. I went into the telecom industry when those things were being replaced with digital switches (circuit boards) and now they are the size of a desktop pc if not smaller. I can still remember how loud and big the switch rooms were.
I spent a large part of 1958 cleaning these bloody things, Franklin Exchange, Adelaide, South Aust.
One reason shorting across the power bars might take the end off your spanner was that a typical exchange would have an almighty 50v backup battery connected that would keep the exchange, and the emergency calls that use it, running perhaps for days through a major mains power outage.
Exchanges batteries (2 off) were originally specked to support the exchange for 24 hours with back up generators to support them beyond that. In the later years of strowger, it was accepted that due to the increased traffic volumes, the batteries would only be needed to support the exchanges for 1 hour before the generators were fired up. In practice, the battery support was probably somewhere between the 1 hr and 24 hr requirements depending on the size of the mult and the time of day. The batteries themselves each had 24 individual lead acid cells, and in the bigger exchanges each cell was an open top box roughly 40” high, 40” deep and 24” wide. Laid across the top of the plates (run width ways) of each cell where two pieces of plat glass (run lengthways) at 45* so that they formed a gully so that the engineer could pour the sulphuric acid without too much splash back. The batteries were ‘floated’ across the power input from the rectifies to provide smoothing to the incoming current. Each exchange unit had two of everything in the power room, so two rectifiers, two batteries and two standby generators. The city centre central telephone exchange I worked in had a Strowger local (mostly 2000 type, but some pre 2000) a crossbar local (type 3) and a TXE4 local as well as a Strowger trunk, a telex exchange two manual boards and a repeater station. So that was 8 power set ups each separate (although some of the older stuff shared the same power rooms. The sysX and sysY exchanges that replaced most of that each had their own power cupboards and were no where near as exciting.
@@captbeardy Thanks captain, great detail. I was a signal and telecom department trainee for British Rail in the 1980s and the internal phone system still had many small strowger exchanges working at the time. My training involved placements with tech teams for both signalling and comms, and at the end of it I chose to go into the signalling side of the organisation, but I was pleased to have seen this classic tech still in action towards the end of its life. Railway signalling at the time was still mostly relay-based, although processor-based systems were just around the corner.
I have heard the myth about a spanner being vaporised when dropped onto an exchange's buss bars.
@@stephenw2992 that’s certainly a tale I was told by the ‘old boys’ I worked with in the Strowger exchanges. I can’t verify it as true, but looking at the size of the exchange main buzz bars and the fact that in the older parts neither the earth or the 50v bars were insulated (though the 50v was painted red) I can certainly believe it possible. I’ve heard other tails of daring do and misadventure in power rooms, and even seen the evidence of one or two, but people do like to exaggerate 😁
And then of course there’s the Christmas we set up a bar in one of the CTE battery rooms supplied by one of our number who was also the chairman of a local rugby club.
Ah, nostalgia is not what it used to be.
@@stephenw2992 believe me no myth.
This takes me right back to my apprenticeship days at BT, I worked on everything from UAX13 to TXE2A :-)
The ringer and busy tone cam were very interesting and such an elegant solution.
I'm in Canada, and took a huge interest in the old school telephone network once I started contracting for the phone company 15 years ago. They still have some vintage equipment abandoned in place in most older CO's. I've taken many pics & videos over the years. The outside plant has been hanging by a thread, and many areas still have the same cables and terminals from the mid-60s. I had been in contact with a retired phone man who ran their museum, hoping he could give me an official tour, but he got sick and passed a few years ago. Anyway, a couple interesting resources online are the Classic Rotary Phones Forum and Evan Doorbell's phone trip recordings, although they're more focused on North America.
The organization of those cables is really impressive and satisfying.
This is amazing! I was just thinking about how much I miss land lines and what would it take to set up a private copper wire network.
sam im a collector of all things strowger and this couldn't of gone to a better place welcome to the world of vintage telephone equipment
Great find, those wiring harnesses. Thanks for the upload, 👍
You have no idea how much I would likento go to that space and work on projects especially to open a museum
I remember seeing one of these in a (GPO?) surplus store that used to be around/near St. Lukes avenue , Ramsgate, when as a teen in the 1970's we would wander around hoping to find treasures we could afford.
no way!!!!!
Theres a lot of special shaped tools for cleaning units.Looking at the cables people were taught how to place them in the correct way !
You need bank tape for the hook shaped tool.. I spent hours at telecom cleaning banks..
I am from Malta, where telephones ran on Strowger exchanges up to the 90s! I remember seeing one of these exchanges in operation when I was an engineering student at university, around 1993 or so. Very noisy device. One thing I remember which I'm not seeing in yours was automated rotary switches that would search for unused lines. Since the line would be short circuited (on hook) it would have no DC voltage across it, lines with voltage would be skipped. Of course, as the contacts aged more and more live lines would not be detected resulting in crossed lines - one of the wonderful artefacts of the Strowger system. It goes without saying that there was no such thing as call logs, the phone bill was just a count of 'pulses'. Also phone calls had a fixed charge for any length of call - I remember calling my girlfriend in the evening, going to sleep with the phone still off the hook and saying hello to her in the morning. Those were heady days!
You could also use it to dial up which synth you wanted to listen to, and use another line to dial up a MIDI destination to send keyboard data to. Have a station with monitor speakers, a keyboard and a couple of dialers, one for the audio and one for the keyboard, then the correct dialing pair would allow you to play the corresponding keyboard.
Since you first started these Strowger vids I've been picturing a telephone exchange on stage playing Kraftwerk's The Telephone Call. That's my ring tone btw.
Ha worth a go
I need a strowger relay sound for my ringtone...that rocks !!
This is amazing for, my dad used to be an engineers for BT in the 70’s and 80’s. I used to go on call outs with him the the exchange and the noises of all the calls going through were amazing back then. The are they were kept in was huge like a big gym hall. Now it’s all in like one PC?
Wire wrap tools are fairly readily available still on ebay, will make wiring new phones into that setup a whole lot easier!
You could turn it into a dial-up patchbay, that's what I'd do.
That's a bad ass idea.
dialing some patches could go through a modulator/demodulator and quarry the web for users' at home created physical patches.
Sick idea,, also cool pfp love to see a fellow transistor trans sister
@@HBCrigs Thanks! Also, back when I was a bit emo-er and listened to Korn all the time, I called myself the "Twisted Transistor" all the time! Happy pride month~
Excellent flags 👍 and cool dragon sona! 😊 (plus obviously neat synth idea - ever since Wendy Carlos blessed this field, us trans women have been drawn to synthesisers!)
your videos are always so interesting. i never know how anything works, but its always so cool to see it all and how you're so knowledgeable about everything
:D
LOL I have the same green phone attached to your exchange, came out of my Nans house in the 80's and an identical black one that was on her extension line upstairs. Dad and Grandad GPO and BT 60 years between them, now I've done 25 years in telecoms.
The last working strouger exchange working I believe is in Holborn.
Blue, Orange, Green, Brown, Slate, White, Red Blue, Yellow, Violet.
As an apprentice I was tasked with building a battery back-up bank for one of this thing's successors, the System X exchange, in our lab environment. Just as I was connecting the final cable onto the -50v battery terminal the spanner slipped and the other end contacted the frame, which was unearthed. I had been given an uninsulated spanner by the supervisor and as a result there was a loud bang, a flash and when the smoke cleared I could see that one side of the open end of the spanner has welded itself to the frame, but this was no longer connected to the spanner itself as there was a good 5mm of it missing! Those battery banks were rated at 50v / 100 amp continuous and could deliver a lot more than that in a short circuit condition. My supervisor got a proper bollocking and went to one of our other sites to hide for a while! This was all 30 years ago now, happy times.
Mate can't wait to see what you get upto over the next few years .
You are a long term investment bro .
Your way of multi generationalism and simplifying these complex processes.
Your enthusiasm for your craft is awesome too bro .
Mate you sound like Neil and look like vyvyan so good bro .
I remember shorting a bus bar whilst working on the top of the rack and the molten bits of my spanner set fire to my mates T'shirt who was standing below me. To think it was only 50v DC but the current load..well!
My mate did that in our exchange.. he was pulling a metal legged chair between the rack and a travelling ladder.. and the leg rubbed off the blue insulation of the bus bar.. and it was also in contact with the frame.. BANG!!.. the chair leg was destroyed.. the rack went very quiet as the 50v fuse had blown.. we rushed round to find him looking white faced. Ha ha ha.. good times…
I wonder if back in the day, the crackling heard over the line while having a phone call was due to this sheer amount of mechanical contacts of relays and switches. I had always thought it was due to the cables outside being moved by the breeze, but seeing such machine changed my mind... I miss those crackling sounds a bit, it added some thrill to the conversation.
You shouldn't be hearing crackling once the call completes unless the contacts are extremely dirty. Other possible sources of the noise are the carrier or radio links between exchanges, or the other party's microphone.
You could, however, hear the switch working while you are dialing. Such sounds can be found at evan-doorbell.com
@@user2C47 Johann...I mean Evan and his pals sure got a LOT of historical recordings! I've listened to many of them! He narrated the audiobook version of "Exploding The Phone" by Phil Lapsley. A very interesting character 😁
I can't wait to come see the museum one day! My grandmum lives in England so next time I come to visit I'm going to try and see the museum, hopefully it will be open by then.
I used to work for BT and look after both Strowger and Crossbar exchanges.
I wish you all the best on that project.. they are quite a bit of work I have not worked on anything like that for over 40 years now, if I was not in Australia I would offer to help get it going
You will need another power supply
telecomms usually use a + earth
That museum is shaping up nicely!
I love that I started following you for the DIY synths and we've gone on a journey through starting a museum and now we're into vintage telecommunications 😆
Also, yes! The sounds on my MPC are AMAZING
This is awesome! Thank you so much, I’m also interested in telephones, but will be honest trying to get my head round how the exchange all works together. More telephones exchange videos please!! ☺️😀😀
You dude are the best so glad you got that rack as I know loads about it
I remember when I was a kid following along with my dad who worked for the Swedish state telephone department "Televerket" and going into a local switching station. A small house jam packed full of clicking relays. And a few years later when Ericsson released the AXE switchboards the station was empty except for a half full rack tucked into one corner
This man is insanely smart!
*I LOVE HIM*
Remind me of Going to work days with my Bio Dad and going into BT Exchanges back in the 1980s ~ 1989 They Were doing the Analogue to Digital Conversions + Tours of Mercury Rectifiers + Lift Machinery + Backup Generators + Battery Rooms + Transmitters
Even taken a Good Few of these Apart due to them being Scrapped
One of my previous job's for plessys in the edge lane Liverpool factory was a assembler and t 2000 switch adjuster great. Times 1969 to 1978 happy days 👍👍😉😉
Those would make a gorgeos Dieselpunk sequenzer.
Wow , mammoth task ahead of you. Love your passion for these sort of things
Oo what would be fun is to have the exchange connected to various recordings and hide the numbers around the museum.
I remember my dad showing be one of these working for real when I was very small. It was a small PABX in his office. Even that was amazing!
Dang this is what I have been missing all my life, I'm going to get a 50 line phone exchange for my bedroom, makes perfect sence =D
you could plug tape decks or something to some of the extensions and play music on loops and have a list of numbers and a phone that people can pick up a phone, dial a number and get to hear a song playing and different numbers will play different songs, or synths
Esxellent idea. The GPO had some nice playback machines in the 1960's if lucky enough to find one or two.
There used to be a big Strowger factory on Edge Lane in Liverpool. It ended up as Marconi until that went pop after the management made some very bad decisions in the early 2000s.
And now part of it is a Range store and another bit is a Travel Inn.
I used to repair these.. but it was for international telex.. in the city of London.. was 50 volts to drive the equipment.. and 80 volts for the signaling..
A ops B ops CD. :) I spent nearly 40 years on transmission, but if I recall correctly you will only be able to have as many calls in progress as there are linefinders. One linefinder allowed up to 48 subs to access 1 group selector. I think, it was a long time ago.
This is so cool 😎 Sam you are a mad genius and next level awesome!!!!!! Can’t wait to se what you will come up with next
The Tunny Machine at Bletchley Park (designed to help break the Lorenz Cypher) was based on uni-selectors used by the GPO... Obviously later replaced by valves of Colossus.
You going to lure the retired BT engineer back to help you with that purchase.
In the 1990's the Highlands of Scotland were eventually all turned over to the digital telephone exchanges, and the old exchanges were removed for scrap.
But....!!!
A local "scrap merchant" packed them in shipping containers and sold them all to India.
One of the electrical supply company's substation still has a working version of a single "exchange", as it still has a dial telephone that clicks and whirrs when you make a call, but you can not phone a business with "push button options" to reach a department.!
I wonder if he has seen that Garage 54 Video, where they made horns sound different with air, helium and sulphur-hexaflouride. I think he could make a synthesizer out of that. Just with Gas and no electricity. :D
I wish I was on your side of the pond mate, I would definitely check out the Museum of Everything Else. You're having awesome fun with this old technology man!
I understand very little of what you talk about but love your videos so much bruh
Adding piezo microphones into selectors so that they would "listen" to relays and outputting that signal as triggers for modular would be nice. Or maybe whole interface between this and kosmo for dialing numbers or routing cv/gates/audio through it.
Check the history of the Telharnmonium instrument. It might be fun to pick up a telephone in some corner of the museum and dial to any music/noise/tone/muzak producing instrument in another corner.
Love this mad man.
Cheers.
Can't wait to get a couple friends and a truck so I can move the old Nortel SL1(with Meridian Mail and old HP console for admin stuff) out of a hotel I do work at and into my personal phone museum. It's basically a mini version of the DMS100 that runs many North American phone exchanges and can even use some cards from the DMS. I would love to get the Redcom MDX mechanical switch from a certain exchange in Alaska. I loved the sound of that thing when it was in service.
If you mean an MDX386, I have several shelves working, and they don't make much noise, as with the eception of the line card relays, they are PCM switching.
@@leejgen8754 They have/had a 384 up in Livengood and there used to be a test number you could call that would read off temps, humidity, etc and then let you listen to the room for about 5-10secs....lots of clicky clacky gear in the room. The exchange is still using the old error messages (CBCAD, NIS, etc) they recorded in the room and you can hear the switches in the background. It was also the last exchange in North America to respond to 2600 and bluebox tones.
Hey Sam, have you considered building an adapter/converter that would take an incoming cell signal to trigger the exchange and in turn trigger a sound source of some kind? I could see it being super cool as a guest to the museum if dialing different numbers on my cell phone would trigger, lets say, a sequence on the relay sequencer or a bunch of relays triggering old telephone bells tuned to different pitches.
ie. Dial a number on cell, watch the relays do their thing, hear the them from 2001 played on old phones.
I wish I had your technical skills. I find this and many of your other projects deeply inspiring.
Now you need a lot of old answering machines with looping tape tracks to patch through that. Either that or a lot of different kinds of various phone ringers. Either way, it's possible to make something interesting result from that thing working.
Glad to see you are doing good Sam, respect mate from sunny 🤨 (rainy) Cornwall.
This exchange was originall from a village In Cornwall!
If you can get two running,set each one up to simulate separate mini exchanges with phones attached to allow demonstrations of a phone on one calling a phone one the other
hey up im just looking through the comments but thats what i ended up doing. i have them boith currently about 10 phones and 10 synths wired in to each. neqw video coming soon check this museum not obsolete youtube channel i chat more about it
I took one of those same systems out of commission in a hospital once.. i played with it.. a lot.. lol.. if you take the power supply and run it to its max power (50v) you can cross some jumpers and they send certain co lines to house lines but since theyre not working ie no ring current then they twitch and buzz like what you hear in the background of old telephone operators sound clips….
Tell you the truth tho i ended up blowing the hell out of it. In that room they had a 480v switchgear and i ran it to the mains when the hospital was dead one night and it friggn looked like some 1980’s scifi movie with it arcing through all the station lines and all.. exploded all the lights and melted a bunch of it.. was fuggn awesome…
😃 When you just bought a giant piece of rusted cumbersome junk and you keep saying "it' not that bad... it's ok... with contact cleaner... it should, etc..."
I love such projects!
OOOoooh you can get two of those old school cog dial phones, then allow your visitors to call eachother. That would be epic
thats the plan!
I think the demonstration unit already does that
@@thewhitefalcon8539 indeed
Hope you can make a telephone call when it’s done, imagine putting it all together and you can’t use it to ring someone without an old phone
Check my
Latest video on it
I’m so glad that what I said a few months ago about how you should buy old telephone equipment to let your phone collection call each other; has come to pass!
Fully down the telephone rabbit hole
The wiring and tying of those cables is just so meticulous it's fantastic. Compare that with the average Eurorack enthusiast's plates of spaghetti.
You just gotta run a telephone line to all of the other musical devices in the museum so you can dial up to any of them and listen.
Very cool. I wonder if you could do something with a mechanical traffic light controller. There must be a few of them out there
I have been trying to find one ha
5:40 the guy who already wire-wrap that is a god!!
the spiral things is called "wire wrap" and it does take a bit of practice but once you get the hang of it really dresses in cable and cross connects. at least they are called wire wrap in America could be different in the UK but would guess it is called the same. Try to find out some one who works in a central office "telecom" near you willing to sell you some older tools they are pricey new or donate some older tools for you because using proper tools makes the world of difference.
You know all those relays, stepping-things, and selectors, are all going to make different percussive sounds. You might even, if you have parts to scrap, rig a couple up to a cymbal or a woodblock or something. And then you'll need a sequencer... which it already has. First Strowger drum machine? It'd be amazing! You could program sequences either with it's many switches, or use the "RAM" that's reified in the selectors, to store 16 steps or so, dialled in on one of those operator console telephones! If you have one...
Actually not just a relay, but why not 50 relays? That'd be a unique sound, and get past much of the need for amplifiers, which of course don't exist, the best you'd get would be a carbon microphone. Did you know carbon mics were the original amps on telephone lines, before thermionic valves? Literally a carbon mic, and a magnetic earphone, just like in a phone, mechanically attached as one manufactured unit. Worked cos of the unusual property of the carbon mic as being a variable resistor. So driving one with a higher voltage than comes in to the earphone, gives voltage gain.
It'd be great to make a musical instrument from this, and would be in your style. Get a relay to buzz at a few hundred Hz if you wire it up to oscillate, but that wears them fast, there's always a spark between the contacts. Set the frequency with a big cap, and have maybe an octave to play awful low-frequency lo-lo-fi ditties. If you're worried, use brand-new relays you can throw away if they burn out.
I would even dare say I'd prefer it as an instrument than as a working exchange. Depending on how many of these units still exist in museums, if there's already plenty, I'd modify it into an instrument. Non-destructively, you'd only be rewiring it, no mechanical changes needed, allowed, or desired. Being able to dial in a sequence like a phone number would be epic! When you're dead, and, still intact, somebody not yet born collects it, they'll think you were a maniac!
As an intact original machine, it would put across it's immensity, complexity, and power. Demonstrate how we did things before beige boxes with an Ethernet socket on the back. This is the idea, the formal logic, of a telephone exchange, made into flesh, directly and literal-minded, in electromagnets and metal. "When all you have is a hammer", cos electron beam lithography hadn't been invented yet.
But the working principle, the need for it, and a real understanding, comprehension, of what it is and what it does, how and why, most people would not get. You have to know it, to love it properly, and the people who can do that, already do do that. So the masses wouldn't understand it, and the geeks don't need it. So I wouldn't feel guilty about instead wiring it up to a drum machine you could telephone patterns into. Shit, you might connect it to the public network, or even to a cellphone! Ring it up, feed it clicks, pulse dialling, and party like it's 1891! Call in, program it, then hear it clatter and sing down the line through that carbon mic! You could post the phone number here, THAT would be a museum piece!
Yess
I didn't expect this journey when I subscribed a couple of years ago. I do enjoy it though!! Great content xD
To be honest I would like to be telephone exchange mad too lol those things are fascinating AF, Lucky for us lol you spend all your money on them and make videos for us to enjoy, Thanks for that Cheers Mate!
Would be neat if this could somehow mesh with asterisk to make a VoIP pbx. Perhaps add a function where blue boxing could even 'control' it.
There's quite a few people that've done that, look up C*Net & NPSTN, pretty much hobbyist Asterisk/Voip networks that people connect vintage phones and switches to
And blue box control can be done too using ProjectMF asterisk patches
My dad used to manage the centers the us versions of these was in. Sadly though he has Parkinson’s so I can’t really get much info out of him on these.
I remember going into one as a kid.
Sounded like a million typewriters going. Then they replaced it with digital in the 80s and it took an eighth the space and just fan humming instead.
Shiesse. Man when I left my last house, I left a toolbox full of armature adjusters, relay spring tensioners, bank cleaners, test probes, original black rubber butt (careful now), feeler guages, home-made 'earth flasher' etc.. Ahh. A bunch of goodness... Oh yes.. Busbars - NEVER short a busbar. I saw one being vapourised once.. Wasn't much of the spanner left.
pole wire wrap connectors your need a tool for that loving the strowger vids
If anyone can make this work again it's you. I know nothing about step office equipment. I used to work for Nortel and did DMS switch installs and testing.
The start of the pink Floyd track… money.. starts with the sound of a 2000 type selector
My mum used to work on these exchanges for decades. Not a lot of female telecoms people back then!
The power bus might be blue because it's negative... In the US anyways, telecom was 48v with positive grounding. Many wire tools are available.
yep it is negative
I LOVE relais anyway so this telephone exchange obsession of yours is just awesome to watch. I'm so curious to see what will eventually come from it. Knowing you, it'll be something worth waiting for :D ^____^
I think you could rig it to work as an automatic cabler for a modular synth.
If the issue of world hunger was an antiquated machine from the 1960s you'd have the Earth fed before July rolls around.
There would also be really cool bleeps, bloops, and clicks.
I do expect sample packs of every individual mechanical sound these things make, naturally.
You could have difrent lights and noise makers with numbers to call to activate them aswell as phones on it
Great now you have a system you can fiddle around with, AS it just is a automatic connection system you can indeed make music with it in 2 way's. 1 just the mechanic sound of calling and stepping etc. 2nd the connections it self. Just disconnect the tone dayno. Now you only have the 48Vdc line voltage to deal with. Series capacitor to get rid of that (see old phones thought 4uF or 8uF) to keep the line open you need the coil.
The system it self should be around 600 Ohms. So you simulate a phone dial, pick-up and disconnect then you can select all kinds of "phone numbers" to select sounds etc. You can then use it as a big sound selector though dailing numbers. But the limitation is lines. It is a 1 to 1 connection system. Then the system can f.i. only handle X-times lines. Think you can from 1 dailing side throug capacitors connect that to 1 input. or 1 output. Automatic dailing can be achieved with relais and some cpu boards. Would be a great project. Wow. Normaly phones work in the range 300-3400Hz. But if you use right coils and capacitors you can reach the whole range. You don't have to deal with phone line amps,long lines, PWM systems to step up to other districs, How ever in this tempo you have your own telephone exchange company soon.LoL.
thats somewhat the plan!!! thinking of sending PWM over the lines to be honest but lets see! :D comparators on either end