SAMPLES AND 10 MINUTES OF STROWGER/PHONE SOUNDS FROM IT HERE :- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-M406arpS7ZA.html or any old phone memories? By the way regarding power I was wrong on the motor! That is on 50v dc and outputs 75v ac for the ringer. As it says on the actual motor if you look closely ha
"At the first stroke the time will be..." (in tones of crackly received pronunciation): ~ Ratchet selector sounds ~ electromechanical orgasm-ish / Awesome. Ratchet selectors into chunky pixels , dynamically ? That's on another level. Roll over Captain Crunch.
I have memories of old rotors dial phones like that, when I was a kid in 80s I got in to trouble, as we had rotors dial phone like that and it was rented from BT British Telecom and I wanted to know how it worked so I took it apart, luckily when later and we had to phones, also have memories of using phone boxes kiosks which I have unusual obsession with unlike other people I also love the later phone boxes, and interested in phone phreaking and technology and of talking clock and Radio and TV and computers especially history of technology and how it works.
My grandmother had a old dial up phone that was in operations from the 70s till 2019 . When I was around 10 I would tap the hang up switch in a particular timing to dial numbers since I thought it was cool not to use the easy dial up wheel. 😅
@@porleg ""this has only been around for a day" 13:01 I just cant believe the sheer volume of amazing shit he gets done - and finishes - and thankfully shares. he is like the ultimate segue into awsome shit lol. were are now at analogue telephone exchanges now where next!?
Shout-out to Richard for being such a nice and generous guy! I love seeing these retired guys who's careers have kind of been forgotten be given a spotlight again, it's really a nice way to get a deeper glimpse into the past and the history of electronics and how that fed into music etc. Thanks Sam and thanks Richard too!
Be careful with that motor, if it's running for a long period, it may get really hot In one of the exchanges i was working in, the label was discoloured from heat The phone is called aa butt because it's short for 'Buttinski' I actually helped install a crossbar exchange to replace the last manual operator exchange in england, it was Abingdon in 1975
Cool on the motor! Yeah if anything it’ll be running for an hour at a time. Setting it up on a timer so people can start the display and it’ll run for 5 minutes etc! Cool!
No way! Small world. I come from near Abingdon and a friend was head of IT at the nearby Rutherford Appleton Lab. They had the UKs first data phone line installed, wired straight to Abingdon exchange. He used to tell a story of how the line would go off hook, and the modem would make a load of noise, and then some old dear at the exchange would be very confused about the noises coming down the line. Abingdon exchange got the top few floors converted to flats a while back, as all the SystemX gear was removed to make way for all the soft switches. What once took up an entire floor is now a couple of racks. How things change!
@@edwardbyard6540 Small world indeed I was installing racks on one of the floors, even finishing the load in when our supervisor got his foot trapped under one and had to go to hospital, the racks weighed about a ton, about a year later i was testing the suites of racks So, Stratton way exchnge now has flats as well as the exchange ?, thery probably wouldn't have got any sleep if the crossbar system was still there, though not as noisy as the strowger :D
@@LOOKMUMNOCOMPUTER in the museums over in the states they run all the time 24/7 (they are meant to be running for years at a time) i believe they have entire exchanges in the connections museum with different types of switches, check it
I worked as an installer for BT between 1988 - 92, when the new System X was being installed and all these strowger units were being removed. If your went into a large exchange with these fitted the noise was amazing....still find them fascinating to watch, and it's great that some people are still collecting and preserving these things
This thing looks almost exactly like one we had in our village. My dad was working on telephone station and he showed me how it works. I remember it was producing very rhythmical switching noises. It was amazing.
Sorry, Gen Z speaking o_O I remember visiting the glorious Museum of Technology in London at the age of 6. I didn't really understand a lot of the stuff there but I have a very clear memory of this exact setup being displayed. And I was just blown away thinking this is the most beautiful thing I've ever seen. FFW 13 years and I ended up as a student for mechanical engineering...
I was introduced to a working soviet relay computer while I was only 6 in 80s... and it ended up being a graphic designer and an educational cyberneticist/methodologist.
Recently, Techmoan posted a video about train timetabling tapes, and mentioned that there was some old rack equipment. Should try and contact the guy who gave him the tapes to try and get a hold of those rack units because they probably have some cool vintage telecoms equipment inside of them.
The coolest bit of trivia I got from this is that the ring tones for all phones connected to the same exchange would be synchronized by the virtue of being a tone modulated by a motor and than the signal shared by all the phones, so 2 people sitting on the oposite ends of the town would listen to the same dial tone.
Yup, and the phones would also ring in unison. Well, actually that not strictly true without getting my notes out I seem to remember that ringing current was broken 66/33 66/33 0/100 (brrring brrring, brrring brrring) and so the ringer would have three output cams set 120* apart. Same with ring tone, and busy tone. Dial tone is continuous as is Number Unobtainable. I think that S and Z pulses were also sourced from the ringer which were used all over the exchange for timing things and also meter pulses (though I think the exchange clock migh also have been involved in the meter pulses) good grief, though I’m stretching my grey matter here.
@@captbeardy Could you elaborate? How does that lead to rings in different phones not be synced? It is fascinating but I fail to follow the dots. Do you mean there are 3 separate ringer outputs and some phones are connected to one, others are connected to others?
@@Thorinbur ok, I’ll try, it remember it’s over 35 years since I worked on this stuff. The ‘tones’ and ringing current are all generated by an oscillator as continuous tones/current. I forget the frequencies, because it wasn’t generally important wine faulting this kit. Ringing current is, as stated 75v. Taking ringing current as an example, the continuous tone is presented to the inputs three sets of contacts, the output of which is distributed across the exchange to Final Selector racks to balance the load. The contacts are ‘broken’ by the mechanical action of cam lobes to give the iconic ‘brrring brrring pause’ in a ratio of 66% on and 33% off. The three sets of cam lobes are set 120 degrees apart so that output is staggered. So you get Cam1. Brring brring Cam2. Brring Brring Cam3. Brring brring I’ve still got some course notes somewhere, but I think that is about right.
@@captbeardy Appreciate you taking the time. I think I get it now. So three staggered cams are conneted to one constant source so that when one source is connected by the cam other two are not and it is done to balance the load. And that will in turn make it so if you are connected to different "lane" the ringers wont be synchronized. I never thought about how many physical connections there were in the first phone systems. Internet is routing packets reusing same physical connections between routers. The idea that old phone networks would literary connect a physical cable using relays and selectors to a signal source and the source is connected and disconnected by a cam gear rotated by a motor... Amazing. Thanks for sharing the details.
No problem, it’s nice to stretch the very matter back to a simpler time in my career when every day was a discovery. The amount of physical,equipment that could be involved in a single,telephone call could be quite boggling, especially for a long distance trunk call. The kit represented here is just for,a 5 digit local telephone call. Consider,how much was required for a 10 digit long distance call when voice amplifiers, digit repeaters and various multiplexing equipment was involved. And long distance calls weren’t just simple step by step as represented here, but required register translators so,that a common STD code could be used anywhere in the country and still end up,at the appropriate destination. On top,of this there was an added level of complexity with something called the tandem network which was a clever way to reduce the number of interconnections required. Because you needed a physical discreet link to be possible between every pair of phones in the country, the optimisation of the network becomes a very complex mathematic model very quickly. Consider that this was all done with relays and selectors similar to that represented here. It’s mind boggling in the extreme, and I’ve seen a lot of this kit in action.
I'm old enough, just, to remember hearing these thing operating when we walked past the telephone exchange. Imagine how much noise it would make with a large exchange full of selectors clattering away.
Thank you to all the engineers who connected our world with these mechanical machines. Big thanks to those who still maintain them and keep them running. Old tech is still good tech.
This really belongs in a museum, there are less and less actually working systems around ... Great job scoring this ! Hat off to Richard for building this demo rack !
I'll never forget the scenes in When A Stranger Calls in the telephone exchange as they try to track the call. Rows and rows of gigantic electromechanical exchanges rattling away really made an impression on me.
This is excellent....I joined 'Post Office Telecommunications' in 1979 and this was the soundtrack to my early working life..brilliant, thank you for doing this and putting it on here 👍
Quite a few of my colleagues were deaf as a consequence of ‘enjoying’ that sound rather than the wearing of ear protection. A hundred racks or so of this stuff made quite a racket, although hearing a single call going through in the middle of the night is just a bit spooky 👻😃
Worked in a Strowger exchange in the late 60's as a TTA (Trainee Technician Apprentice) for the then GPO. At that time the average exchange had 5 people there to maintain the equipment. By the late 80's one man and a dog would look after 5 exchanges. When the question "What was the dog for?" was asked---- the answer "to keep the man away from the equipment" was the reply. happy days. Good luck with you project and you will never forget the sound of those selectors working away.
A minor minor pedantic point, Strowger was still in use in the Uk into the early eighties rather than the late seventies. One of my earliest lessons in accepting change was watching the contractors taking out one of the strowger exchanges I’d worked on. As you can imagine it took a lot of care and attention to keep those switches running sweetly and as a T2A (a junior technician) I spent hours and hours manually cleaning banks and cleaning and adjusting A relays. To then watch the contractors removing those very same switches and throwing them into skips from the first floor windows and then removing the banks a shelf at a time with sledgehammers was heartbreaking. It stood me in good stead though, because I career saw a lot of change in the telecoms business and I’ve been fortunate to have been involved in the roll out of a lot of the tech we all now take for granted. I qualified on Strowger as a TO (the then senior technical rank) before moving off to different things. I have very fond memories of those few short years in the telephone exchanges.
When I hear that ring tone, it reminds me of a Pink Floyd song. I could swear the same sound was in there. Also when Doc's phone rings in Back To The Future. I wonder if you could find another rack with DTMF stuff too. I've always wondered how they interfaced together.
@Maxxarcade, I was about to comment the same thing. Ring tones here in Argentina sounded completely different, so that calling sound is like hearing English in British accent and Pink Floyd, both at the same time.
Hi Sam, I love what you’re doing. Look up Evan Doorbell, he was a 70s phone phreak who made extensive recordings of the US telephone network at that time and has since made a ton of incredible audio documentaries demonstrating how it all worked. I’ve sent him this video as well because I know he’ll love it.
I used to work in a Strowger telephone exchange. I connected the wires at the back of the switch, it was called grading. It was very noisy, especially when there was a "phone-in" on the local radio station. The engineers who actually maintained these switches all looked alike. They wore long dustcoats, were covered in oil (oildag) and their shoes were sandals with grey socks, lol
I remember in the early 80’s having a tour round Swindon telephone exchange. They were in the process of replacing the Strowger gear with the new digital System X exchange. Another thing was there were actually two slightly different engaged tones. Equal duration tones meant subscriber engaged, and a 2:1 ratio in tone length meant exchange engaged - no free lines to connect the call. And if your mechanical dial failed, you could actually press the hook switch on the phone the right number of times with pauses to dial a number.
Love how we went over the years from fun intense fish-eye bodge soldering punk style to watching an old guy talk about telephone exchanges and yet it still feels punk.
back in the early 90's when I was 12 I used to bike past a scrap metal place and it was full of old Strowger Telephone Exchange equipment, They were upgrading the exchange to electronic and had no regard to the old gear. I used to grab lots of it and pull it apart slowly understanding how it all worked... looking back I should have kept some
When I started working in the national telephone company back in 1987, these were still in use here in Norway. Motors, selectors and all. They are (were) truly an ingeneering masterpeice.
The analog world is so elegant and complicated and ingenious. Hat’s off to you and your Museum for doing all that you have to not only highlight and explain these devices but to add your dash of creativity and imagination to show that these amazing things can do more than they were designed to do. Honestly, man, so much respect.
Neat. My dad was an exchange technician and for a few years also did the lineman role. Knew everything from the battery room, generators, and clicky-clack relays. From Ma Bell, to Ameritech, to SBC Bell, and back to AT&T. Later on did service calls for alarm monitoring of the phone systems. And the building full of wiring and relay stacks (with library type rolling ladders even) got overhauled to being a mostly empty building with a handful of Siemens routers in the late 1980's. Oddly enough, they didn't mind the knee-high version of me visiting dad at the service desk area as I was trusted to not touch anything nor wander off. Interesting place to see back when it was the electro-mechanical stuff, but no pictures from there that I'm aware of. Should probably call the local IBEW office and see if the union rep could get you in touch with some old retirees. Explain what you're on about regarding the museum and such. I bet you could meet them over coffee somewhere and they could tell you all you'd want to know about that stuff.
what's really nice is that recently, Tim Hunkin, who has a youtube channel of the same name, has reuploaded his video on the telephone, as well as fax machine. He also mentions the stowager relay exchange, showing BT engineers operating it, joking referring to it as "Bash and shove technology." As it's electro-mechanical, sometimes you do need to hit it with a hammer to get it working!
Fascinating to think that most probably you never before in your life have made probably using a dial, or answered one ringing with an actual bell. I'm not all that old, but most of my childhood this was th leading tech. I remember how awestruck we were getting our first pushbutton phones when I was about 9 years old. And the interestingly musical beep beep sounds when 'disling' a number. Took until I was grown up really to phase out most of the dial phones and real ring-ringers. I can't help but be overjoyed with having that familiar old ring sound as. Ring tone on my I-phone.
Mechanical electronics have a special magic about them! That exchange gives me the same goosebumps I got when I saw Alan Turing's Bombe. It's amazing to watch the logic occur in physical reality.
The electro-mechanical era of tech is great to learn with........because you can SEE in working. It's easier to tell what's happening, rather than just knowing there's 1 and 0 going through chips.
I am sure everyone has seen the series, if not you should, The Secret Life of Machines. Look up Tim Hunkin's channel on YT. He is currently uploading remastered versions of the show. The one on the telephone IIRC shows an exchange as it was BITD. Basically Sam is a current day Tim and you will all love watching these old episodes if you like this.
started my time dedagging step x step, adjusting crossbar switches, now I am integrating 5G mobile base stations. The change in communications technology in 40yrs is incredible.
A ops B Ops CD, basic strowger from my BT apprenticeship days in the early 1980's. Personally I was blown away by the Crossbar exchanges (TXK2 / TXK4) which were still electro-mechanical & relay technology but did all of the call connection setup between initial loop and application of dial tone and then upon receipt of the final dialed digit (if within the same exchange). During dialing they just sat and counted the digits into the register until a routing decision could be made.
I never knew that the ring sequence on all phones driven by one exchange would be in sync! All ringing in any house, on totally separate calls, are all driven by one motor, cam oscillator thing! That is cool!
My dad was an engineer at german Telekom, I remember playing with those machines as a kid. We also had a small relais based house telephone version of this at home. It was already massively outdated back then but fun to watch. I remember wiring up old phones at school for a play to get them to actually ring on stage when the actor had to take a call. No one actually understood how I did it. I had to use an old AC power supply from physics class lol
I grew up in the 1980s and 90s in Dublin which was already mostly on digital exchanges with DTMF signalling by then, so this insight into electromechanical switching is fascinating. Weird things sometimes still happened -- in the mid 1990s I picked up the phone to make a call and there was no dial tone. Instead, I could faintly hear tens or hundreds of voices and a metallic hum of interference. I could just make out a few voices here and there, shouting confused hellos, swearing and laughing. Seemed like all numbers in my local exchange were inadvertently connected for an hour or so.
🎶 the Final Selector..... 🎶 Incredible to have all of this explained by an expert..... those BT engineers were smart guys to understand and work with this equipment of a daily basis ! Thanks to Richard ! I expect to hear some new track with the selector and relay mechanical noises creating a wicked baseline....
Am I the only one that when I hear the word selector thinks for a split second I’m listening to a DnB MC? “Final Selcta!” Fuhh! Fuhh! Fuh! Fuuuhhh! This museum looks like it’s going to be a must visit for all us techs nerds, keep up the good work!
8:58 - " the only 2 digits that differ are the ones being dealt by the final selector " could be good lyrics for a telephone exchange inspired kraftwerkian jam :D
For the 3 phases of ringing, you could 3d print your own cams so that you can have custom ring-tones to use as musical rhythms elsewhere in the museum.
Large Strowger exchanges had amazing lead-acid batteries and huge bus-bars to carry the thousands of amps of 50Vdc around the building. I heard a story about a fork-lift truck that hit these bus-bars and pierced the insulation - they said it quietly melted the side off the fork lift (and started a significant fire) must have been 100,000 Amps or so.
OK. So a few relay sequencer videos ago I mentioned seeing a house full of this equipment as a 5th or 6th grader in a switching station located right across the street from my school. The image at 5:45 is exactly what I remember seeing except it was all crammed into a gutted one bedroom house, and I remember seeing all the inner working bits, as in no covers over the individual switching units. Heat dissipation? maybe? Faster to service? I have no idea why. What impressed me (at age 11) was learning that each switching unit was responding to someone, perhaps 20 miles (or so) away, dialing a number on their phone ... at that very moment. I realize that sounds a bit obvious but it was all pretty wondrous for an 11 year old. It's amazing that this equipment didn't hit the scrap bin years ago.
This is absolutely brilliant, have often seen this kind of old telecom equipment in museum displays but to see it actually hooked up and working is fantastic. Really need to pay a visit to the museum in due course!
Very interesting channels and videos, don’t know, why the algorithms didn’t alert me before, @9:33 the ringing machine was designed to run continuously, 24/7 year after year, otherwise no subscribers phone would ring and no caller would hear any tones, with occasional changeover to the backup ringing machine for maintenance.
This is beyond cool! I used to imagine as a kid, what was happening when I would dial my buddies. I took apart rotary phones, but I never got close to figuring out this side of it all. So glad to see a working version still exists. Good game!
This was really cool and educational to see. My grandfather was a BT engineer and I think probably dealt with these exchanges at times. Still have a ton of his old tools and equipment!
remember working on one in 1990 in an old chocolate factory when on work experience with bt, we had to clean lots of chocolate powder from the relays, great fun.
This brings back so much nostalgia. While rotary phones weren't common when I was a kid, I used to use the trick of clicking the hang up button to dial all the time. -- On a side note, it's also fascinating that the button style phones use a sort of cartesian grid with tones to determine the number being used. So, every push button on the phone was two pitches, one for the x-axis and one for the y-axis. On some of those older phones, you could press two buttons from the same row or column, and hear the tone that related to that position. -- At some point these telephone exchanges had to work with both options.
