At the Connections Museum: the insane telephone technology that led to today's computers
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- เผยแพร่เมื่อ 18 ต.ค. 2022
- We tour Seattle's Connections Museum, and marvel at rarely seen, fully functioning telephone exchange equipment, from the electro-mechanical 1900's to the all-computerized system of the 1970s. Next time you use a modern computer, give a thought to Bell Labs who invented the transistor and the Unix operating system, all driven by the need for better telecommunication technology.
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www.telcomhistory.org/connect...
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I hired on to Pacific Northwest Bell, in Jan 1963 as a frameman in this very building, running jumper wires for the #5 Crossbar office that was cutover into operation that year. During the time I worked in that building, a second floor was added, and a second #5 Crossbar office installed. Soon after that a building addition, doubling its' size, was added to the north end of the building. The expansion was needed for a third #5 Phase Three Centrex office that was installed to serve the Boeing Company. I just turned 80 yesterday, and boy does watching this video bring back memories. Thanks!
Thanks to the people in Seattle that built this "working" museum and keep all the equipment running!
Working museums is best museums
@@lachlanlau That's true! But I didn't know that before I started to watch the AGC restoration series on this channel.
amazing feat of engeneering... and keeping this alive, i dont have words to describe...
My father told me a story of when he was a kid (late 40s) he used a walkie talkie to coordinate with a friend to dial each other at the exact same time. A few times the phone made a really funny noise but then a voice came on and said WOULD YOU KIDS STOP PLAYING WITH THE PHONES! I’d imagine they were causing those trouble tickets to drop or an alarm to sound!
Maybe!
Wonderful! Thank you. As a teen calling my girlfriend, wheher line was busy, I thought I heard other people hanging up their telephones between the busy signal tones. I had her call me as I called her so we both gothe busy signal. *We could talk to each other between the tones!* Apparently telephone circuits, when busy, were connected to a common busy signal buss.
Wow, each machine was decades older then I thought at first glance, especially the turn of the century stuff. It just goes to show that this stuff was really the bleeding edge at the time.
I couldn’t believe how old the stuff was. This was way ahead.
The thing that always gets me is that Tommy Flowers (of Colossus fame) was working on a valve (vacuum tube) based exchange device to replace a relay unit in the 30s.
Looking at the equipment in this video, one wonders whether it was a sender he was attempting to replace.
People don’t begin to understand how complex telecommunications is. It’s all taken for granted.
Neat collection. A treat to see it all so lovingly preserved. To think that every metropolitan area in the developed world once held giant buildings full of such intricate, ingenious electromechanical contraptions, all connected to each other, and it all worked as a system.
The very early part of my career as an Engineer coincided with the end of the big telephone systems as the drivers of the system. Back in the day, my employer sent me late one night to the Seymour Exchange in Vancouver to swap out a line card in an ATM switch. They terminated 2 million pair in that building. It was amazing to behold. I need to get down to Seattle to visit this place.
Those buildings are still all there in the most part, just having transisioned into more modern technology and then being used to house multiple technology changes. After all having the building, the rights of way and likely cable trenches in place it was natural to pull out the old equipment to make space, and put the new in. The extra space often was then repurposed, either for use as office space, or for servers, or for the billing system archives, on the premise the buildings were already paid for, and saving on cost. Only rarely were they sold off, mostly just those that were consolidated with technology changes making the building empty.
@@SeanBZA sure, and of course you're right. But the buildings themselves aren't interesting, and to me the superior modern / contemporary digital solid state switching tech is very uninteresting, just network plumbing. I'm just here for those ancient electromechanical marvels.
I was lucky enough to see a full working exchange using Strowger switches in the very early 80s. It was incredibly loud, and the person showing me around said you could tell the heartbeat of the area by changes in the noise level. Popular radio call-in giveaways could easily jam up multiple exchanges, so radio stations were given specific central office code numbers (the xxx portion of a local xxx-yyyy US format phone number) so their traffic could be tightly controlled.
My village had a strowger exchange for many decades. A tiny little building behind our primary school. As a teenager I’d walk down and stand outside, at night, simply to hear the reassuring “CLU-CLU-CLU-CLU-CLUNK---ZZZZZZZZIPPP!!” of the uniselectors, and to be entranced by the beautiful, deep red glow of a statue bulb, shining through the mottled security glass 😄
Where I live, the 888 exchange was implemented for radio stations because one station once offered a new Harley Davidson motorcycle to the 5,000 caller and took down most of the exchanges in the city. These were called "choke" exchanges as they limited the number of calls to that particular exchange. Later on, 888 just became a regular exchange after the advent of electronic switching.
I got a tour of our local Bell 700 line sxs exchange in the small town I grew up in during the early 1960's. Later on, I became a private telco tech and managed a hospital network of over 10,000 lines of digital telephony.
In the UK we had a TRAPP system for radio call ins, to stop the exchange becoming congested. The radio station had a special number for you to dial for call ins, and each telephone exchange only had 2 lines to the radio station switchboard
I think for the Los Angeles area, it was the 213-520-XXXX area/prefix that was used for the high volume call-in stuff. If you were lucky and were the "19th caller" you could win $10 of free dry cleaning. :)
I was fortune enough to get into the Telecom industry when PBX's were being converted to digital in the early to mid 80's. The decibel level in some of these switch rooms was unreal.
Examples of magnificent machinery like this must be kept in operating condition and this museum is a great custodian.
That some of those systems may be the only surviving examples is just sad. To those who recognize the value of preserving old tech: Thank You!
It is. Just think, a century from now, this video (accessed by a garage made 2022 tech emulator) may be the only thing that connects that time with these machines.
When I started working for a British Telecommunications company ( you can guess which one) back in the late 80’s one of the first jobs I was involved in was ripping out a huge room full of a PABX 4 for Pan Am at Heathrow Airport. We went from a room of strowger equipment to a Nortel box of tricks on the wall ! There was still a few bits of working strowger kit in the telephone exchanges but soon got replaced by crossbar, system X, system Y etc… I learnt things such as lead plumbing, butt stuffing ( not what you think !), twist & tip soldering, gun wrapping, E & D side, earth A battery B, bells A & B, cosmic, transverse screen, pressurisation and so on….now towards the end of my career I’ve worked on Ethernet fibre provision for the last 19 years and there are still ringing generators, test desks, dolls eye boards etc still in exchanges , still working, as no one has bothered to unplug them or turn them off.
heh heh heh heh heh He said butt stuffing 😁
You definitely have different terminology for telco work over the pond. I'm betting your "twist & tip" is what we would call "twist & tube" for using the wax coated tubes to slide back over the pigtail splices. Your "lead plumbing" would be our "wiping"., as you heated the lead on a joint with a torch and "wiped " it into place with a wiping cloth of heavy multi-layered cotton, or old school splicers poured molten lead from a heated pot with a ladle and would also wipe that into shape while it cooled. Your "Earth" would be our "return", Battery is the same, and we also use a "Positive Earth" system. All of the exchanges near me had the boards on the "test centers" removed long ago, to reclaim space, but every exchange still had a rack with its own test board in it.
@@poormanselectronicsbench2021 hi. Thanks for the comments. As far as lead we used moleskin with tallow but I did also train on the poured method. Twist & tip, we used either paper sleeves ( that we baked in a baking tin over a gas stove !!(usually on paper insulated cables)) or polyethylene sleeves on newer cables before machine jointing then modular jointing came in.
@@andrewrixon2347: When I first started, we were trained to use the 3M series 4000 module, which is still in use today in upgraded forms. I was detailed to New England in 1983, who were using a mix of 3M and Western Electric "710" style modules, which, were rubbish IMO ( although Western Electric used them on equipment shelf connections) , and we refused to use them, sticking with the 3M product. Since the "twist & tube"method usually made was called a "no slack" straight splice, some techs chose to do taps/bridges by sliding he tube aside and wrapping the new wire connection onto the existing, so sometimes we still did that, because the alternative was to first build slack into anything you had to work on.
@@poormanselectronicsbench2021 yeah most of our joints were no slack. I was based at London Heathrow Airport so we had limited access to everything so it was joint it, close it, leave it. We always tried to either injection weld the really big joints ( up to 4800 pair) or use Raychem 4 series shrink down closures. All these joints were on dry cables which we pressurised with 620mbar of desiccated compressed air fed from the exchange with transducers measuring the air pressure along the lengths. Modular wise the 3M took some beating and I loved working with it. We had a single wire “machine jointing” system earlier with the “crimps” in a cartridge. You had to do several test crimps first and the out them through a “go - no go” gauge to ensure the machine was set up right. The first crimps were white, then yellow then modular was introduced.
I grew up in a medium size city which had a Bell office serving the town with SxS equipment in a three story office which was also a long lines repeater office and a coaxial TV transmission office as well. The basement housed the batteries, ring generators and interrupters. The last time they gave a public tour was 1968. When I was a kid we still had to dial the operator to request toll calls outside our own area code, but offices in the area code could direct dial toll calls. Incoming toll calls were automated with the distant city operator able to DTMF signal the local office to connect the call without operator supervision on the receiving end. Bell started an upgrade of the SxS to some version of ESS in 1975 and hard cut over the entire town in one fell swoop, if I recall, on a July evening in 1976. The old SxS equipment and tennis ball tube amplifiers did not require air conditioning, but the windows of the office would be open in the summer and walking by, the sound of many Strowger switches filled the air, punctuated occasionally by the wail of a horn when a malfunction was detected. That old building is still there, now an AT&T facility, and all the windows have been bricked up. There is now only the sound of passing cars on the street.
When I was a kid, we had to make “Station to Station” or “Person to Person” call. The operator would have to go through connecting several operator in series to get to the final destination. Or even Collect call. And it was expensive. We even had a Party Line where we shared the same wire with others. I sure am glad I lived long enough to see how phones improved over the years.
@@oldmech619 Thanks for the reply. Yes, I remember that too. There’s a film in the AT&T archive about direct distance dialing for operators, which showed the old way, where a customer would call the operator, request the distant number, and hang up. The operator would call back a few minutes later after the call was manually connected. By the time I was old enough to use the family phone, the local operators had direct distance dialing, so you could just hold the line for the few seconds it took the operator to connect the call (provided he destination city had automatic switching equipment).
Station to station versus person to person seems quaint now that most calls to anywhere inside the continental US are virtually free. I recall mostly using person to person from pay phones; the rate was higher, but you did not have to pay if the requested person was not available at the called number. There was also the day/night/weekend rate to think about. When I was working as co-op student, I would wait until Saturday night to call home at the least expensive rate. If I recall, it was like $1.10 for a three minute call. That’s probably close to $5.00 now, adjusted for inflation. How times change!
@@wtmayhew My dad made sure the phone was in the the hallway so we wouldn’t talk too much to our girlfriends. Even having a phone in the bedroom was too costly. Remember Dick Tracy’s wrist phone? Now we have far exceeded that dream.
1:53
There is a similar building on Washington Street in Indianapolis. 🧑 Often wondered how long it was there, what was in it over time; and what's in there now..🤔 Also wondered, what area of the city and suburbs it served/ serves.
My parents’ home had a local battery set in the 1930s with a metal battery box holding two Blue Bell No. 6 1.5 Volt carbon zinc dry cells. My dad said a phone person replaced the cells about once a year. Those were some pretty impressive dry cells. The capacity is more than 100 amp-hours. In the very early days in the 1880s crowfoot copper sulfate or later Leclanche carbon wet cells were used. The wet cells also had massive amp-hour ratings any only needed to be refreshed once a year or so. Until Charles Brush invented the practical dynamo around 1880, all telecom was battery powered. Remember the electric telegraph dates from about 1844, so wet cells were all over the Western Union and other systems. Battery boys were used to keep the electrolyte refreshed in rooms full of wet cells in main offices.
Those later dry cell batteries would last longer, so would often only be replaced at the 10 year mark, or even longer. There were still those systems in operation in my country till after 2000, running a few dozen farm lines over open copper plated steel wire pairs, with the poles having every 20 poles a section of 2, where the twists in the pairs were done using a 4 insulator block. Around 50 subscribers per pair, as you did not have a high call volume on those lines. First change was to consolidate those lines so only the far ends were shared, local ones got the new cable gradually laid out, giving each a pair, and direct dialling, till finally the last were done away with.
Still have a 1939 Ericsson wall mounted phone, which I converted, just with 2 wire jumpers, from local battery to remote battery. Unable to dial out from it, as it still has the 90VAC generator, and the mechanical bell with the 1 REN loading on the line. Want to use it for VOIP, but most of the adaptors cannot actually handle an actual real 1 REN load on them, typically 0.4REN. Thus it is now a wall mounted phone holder for the modern smart phone. No more copper phone to the house, gone a few years now.
@@SeanBZA Thanks for the reply. The phone on my desk is a Western Electric 302 with the older style handset with the ear piece with the separate metal plate. The dial is (forget the part number) the one with the porcelain number plate. The subscriber set wall box is I believe a 534A which is meant for common battery and bridged ringing (has the 2 uF capacitor), induction coil is the older long skinny one, not the E-core transformer. The setup still works great after about 95 years of service. I *can* still dial out on the rotary dial. I have VOIP phone service from Spectrum cable which is provisioned by a Motorola customer terminal in my basement. They accept repertory pulse dialing because they’ve got quite a few customers with older alarm systems which can only do pulse dialing.
I almost forgot, I have a Panasonic small business PBX box between my phones and the Motorola terminal. I got the Panasonic used from the usual auction web site for about $100. What a fantastic unit. The Panasonic is quite easy to program and any extension line may be either the Panasonic proprietary phones, or standard 500 or whatever series phones which are auto detected. The only quirk is it seems the only way to record the voice menu tree is through a proprietary digital phone, so I have one digital phone for my manager’s console. Everything else can be done with * codes from analog extensions. The greatest benefit is that having an AVR voice menu has reduced spam calls completely to zero. No telemarketer bothers navigating the menu tree! The PBX transparently passes through pulse or tone dialing to the outside line(s), though it can convert between the two in needed. Curiously, the outside lines as far as I can tell have to be loop start, no ground start, so there is the risk of glare (call crashing where incoming and outgoing calls occur simultaneously on a line).
I’ve also got a few old magneto phones and desk stand phones which are set up for local battery. I don’t use them because I got complaints from people on the other end that they’re way too loud. The old carbon transmitters have an effective gain of something like 50, so they are loud. About 1912 or so, Western Electric actually tried mechanical amplifiers with magnetic reproducer mechanically coupled to a carbon transmitter. The frequency response was not too good. DeForest/Fessenden vacuum tubes became available about 1914. I believe the first vacuum tube amplifiers were installed in a long distance circuit in Maumee, Ohio. Western Electric also did an experiment with a carbon transmitter, unamplifiied, to relay a political speech to horn speakers about 100 miles away. A DC current over 10 amps was run through the carbon transmitter which had to be water cooled.
@@wtmayhew Nice setup. If the 302 is connected to the 534A subset/wall box then it might actually be a Western Electric 250. Those are a variant of the 302 with no ringer or induction coil inside meant to replace old 202 or candlestick sets and reuse the subset/ringer box from those phones. If so very cool to hear about such an old installation still in active service in the full vintage configuration
@@St0rmcrash Thank you for the correction. I should have know better than to try to remember numbers. The desk set is an oval base model 202 and checking the web the handset is type E1. I found a Bell System Practices section on dials, I believe the dial is a type 2. The dial was balky so I disassembled it a few years ago and used clock oil sparingly on the gears driving the governor. The bias spring on the ringer in the subset box is tensioned with a cotton thread wound around an adjuster post. The old thread deteriorated and broke, so I found some period correct looking heavy cotton thread for replacement. The old capacitor in the subset seems to be fine. The old Western Electric equipment is built so amazingly well and simple in design that there isn’t much to go wrong.
I also have a spare 534A subset which apparently went back for depot service and has been updated with a induction coil and capacitor unit which looks like the inside of a 302 desk set mounted on an adapter plate, while the ringer is an older two gong with two long coils, but slightly different from my older 534A. It appears that there was a lot of mixing and matching of of parts going on, especially post WW-II when demand was high and new parts were in short supply.
@@SeanBZA in Australia we had Eveready No. 6 cells, looked the same apart from the label.
I used to repair/replace the cords and plugs on similar switch boards when I worked as a technician in the telephone exchange (New Zealand) in the early 1960's. The toll operators (mainly women) would have us "young" technicians on quite often. Sitting on my pliers and asking "now what are going to do?"
We have come along way since then. I am now 76
I learned UNIX on an AT&T 3B2/300 and a 3B2/400 running System V R3.2 that were returned back to Bell for “disposal” after being retired from 5ESS service. I owe my entire career to the Bell network.
I still have a 3B2/400 in my cellar.Last time I booted it up was some 25 years ago.
I learned UNIX on a DEC PDP-11 and later worked in the MMOC (Minicomputer Maintenance and Operations Center) Where we had around 100 computers running mostly UNIX. Mostly Minicomputers took up two floors of the Telco building. A couple of times I even went back to Bell Labs in New Jersey.
I worked my last 15 years before retirement with ATT. I worked the pipeline contract where we used mountain top microwave that we accessed by helicopter. My last six years were at a gateway earth station. We worked all kinds of circuits and the transport. I worked jobs all over the state of Alaska and some overseas during my telecommunications career.
As a young and former Lucent engineer in the late 90s, I dedicated many hours to reading about and studying the history of the technology in the telecom industry. I’m going to need to make a trip out there to see for myself all the tech I read about, but never had the (mis)fortune to play with. Thanks Marc for sharing your invite with the rest of us!
It says something about quality when the local community college is still running analog phones off of TN boards (now in G650 carriers) that I personally installed in SCC cabinets...in 1992. Don't remember now if that switch was a System 75 or an earlier Definity. I think it was like 2008 or so when the SCC stack was replaced by the G650s and it went from being a Definity G3 with a Processor Pack and became a Communication Manager 5.x with an external Linux server and an IPSI board.
I started down the Telecom path on a Dimension 2000, MAPP panel, and TOPS manuals. Still walking the same path, and in some areas the scenery hasn't changed much. I noticed something which struck me as funny the other day. During the transition between Definity and Communication Manager they kept a linear flow on the release numbers. Definity r11 = CM 1.x, Definity r12 was the same as CM 2.x, etc. It just jumped out at me the other day that CM 10.0 proudly identifies itself as r20 when you query the version number. All Communication Manager really was at the outset was a port from Oryx/Pecos to Linux. The last Oryx/Pecos release was Definity r13/CM 3.x.
Wow, this takes me back :-) I worked in some of the telephone exchanges around Edinburgh in the eighties, working on a project to the do the first automated itemised billing for Britsh Telecom. I was working in Galashiels telephone exchange with some BT engineers who were adding some new Strowger or Crossbar racks to the exchange, part of which involved extending the huge copper bus bars that transported the 50V around the exchange, where each rack had a set of solid copper bus bar conductors which got bolted to the end of the previous frame, with the whole lot then being insulated. One of the engineers dropped a big chrome vanadium spanner and it shorted out a positive and a negative bus bar, which hadn't yet been insulated. There was an ENORMOUS bang, flash of white light and a huge shower of sparks about ten feet across rained down. The two ends of his spanner were welded one to each bus bar, with a three inch gap in the middle where the solid steel had been vapourised :-o I wonder if those spanner ends are still there, LOL :-) Another great video Mark!
Wow! The spanner became a fuse!
When i was at Napier College in the 80s learning about digital telephony we visited Woodcroft which was at the time a big exchange. Of course there was no digital signalling there at all - it was all Strowger and crossbar switching!
My childhood home (1974-) had a phone with turn handle, local battery, and the trap door indicator panel in the local post office. Our number was 78. The switch was the topic of a school visit.
Automation and central power happened in 1981. The phone number gained 4 digits, later another, and finally became 8 digits when Australia adopted a uniform system (8+ 2-digit area code). The 78 persisted on the end of the number throughout.
My nieces cannot comprehend a fixed phone, let alone one with a dial.
I was wondering what would happen to a phone number of it was kept that long, I thought it'd be 00...78 after the area codes of course. I once saw a picture of a funeral home proudly displaying a sign with the words "PHONE 12" on it
When I was very young, I use to accompany my father to work (at NY Telephone) sometimes in the evening and would read those trouble cards (#5 Xbar) and "busy out" bad trunks. I too worked at Bell Labs in Murray Hill from '77-'01 in IC Layout , then Unix System V, Math Research, and finally CS Research (Unix room!). It was great!
When I helped build my first data center from scratch in 2003 the other engineers were really confused how I knew so much about raised floors and AC systems. I had to think about it but my dad ran an ibm tape data center in the early 70’s. When I was very young I spent a lot of time there.
My dad made my birth announcement on punchcards. :)
Great video, very interesting. One interesting fact as to why an undertaker from Kansas City (Almon Brown Strowger) invented the automatic exchange was because a rival undertaker's wife was a telephone operator and Strowger suspected that she was diverting his calls to her husband's business !
I didn't know that each of the early subscribers had to have their own battery just as we do in our smart phones now. If only it was the phone companies that had to replace the batteries in smart phones! I am reminded of the fact that some electric vehicles have more than seven thousand cells in their batteries (which are also difficult to replace). Early technology; don't you just love it?
I remember reading about the Danish telephone service which switched to line power in 1927 and all the subscribers were told to cut the line to their phone batteries. Those that didn't caused their phone to constantly try to make a call and so they spent months troubleshooting and going around to people's houses to disconnect their battery for them.
Since they knew what numbers didn’t disconnect their batteries I’m sure they called them. But there has always been people that couldn’t touch hardware. So I bet if they had to call them they usually had to go out and do it them selves.
@@ecospider5 Honestly, if i got a call that said to cut a battery wire to my phone, i'd have assumed it's a prank call. Kinda like doing tech support and telling someone to press alt+f4
This is amazing, the people who developed and built this evolving technology were super smart.
I have heard of this museum. Now, I will make a special trip to Seattle just to see it!
What a fantastic team of people keeping all of that alive!
Be sure to check out Look Mum No Computer's video series where he sets up a small Strowger telephone exchange, very fun stuff.
oh you bet I’m watching him…
Wow in high school in 1968 I trained as a tech in a phone-switching plant. It was electromechanical with memories, all built in 1936.
As one who worked for British Telecom in the UK, that was brilliant! Thank you Marc.
My father worked for Western Electric prior to WWII and after Ohio Bell, had 14 months training in No 5 crossbar. As a kid can remember the local exchange in town. He was there for cutover on Nov 30, 1949, until retirement in Dec of 1973. We didn't have ESS until some time in the early 1970s although touch tone dialing was available earlier. Sound of the exchange was music to my ears after a long silence. Hope to visit in the future, great example of progress.
I never dreamed.the telephone system was so complicated and i dont know the half.of it .I havent even scrached the surface. Its incredible how much there is to it.
I remember my first tour through the switching office. I said there’s no way that every single copper pair for every line comes in here. My guide says Oh yes they do!! I was kinda blown away. Then they showed me the battery backup system, and the air pressure system, and was absolutely amazed! Great memories. SBC/PacBell
The batteries actually provide power for everything and are kept on a float charge. In the event of a commercial power outage the batteries would then provide back up power and prevent service from being interrupted. The batteries alone could power everything for about 8 hrs. This would give the power crew time enough to get to the central office and start up.the emergency diesel generators.
*Air pressure system?* For what? Blow battery fumes away? Extinguish arcs?
@@robertgift The big outside-plant copper trunk cables, containing hundreds of wire pairs each, were pressurized with air from the CO end to keep water out
I love this museum. When I first visited everyone there was a former Pacific Northwest Bell technician or engineer, most well past their retirement ages. In subsequent visits some younger faces, like Sarah's, appeared.
The museum really owes its existence to the rise of digital switching in the telephone network (and the breakup of AT&T). When Pacific Northwest Bell decided to retire all their electromechnical switching equipment in favor of digital equipment, the Director of Engineering, Herbert Warrick Jr., decided that part of the endeavor should be preservation of the equipment they were about to replace. My understanding is that the panel switch was particularly difficult since it had been assembled in place without the same sort of modularity that was designed in to later generations. If I remember right, they had to cut a hole in the wall of the central office that housed it in order to extract it. The museum itself occupies space in a central office made available by the decommissioning of electromechanical switching equipment.
The different switches in the museum are interconnected and so calls can be placed that span different switches. You can hear the call move across and within the switches as teh contactors and relays clatter and click. Back when they were in service it must have been impossible to pick out the activity of a single call being switched except perhaps in the dead of night.
It's definitely worth a trip when visiting Seattle. It's also worth visiting the Living Computer Museum, which has many generations of mainframes, mini and microcomputers. Probably better to visit them on two separate days, even though they are both in the more industrial area south of downtown; there is a lot to take in.
I'm an old Panel man. After they had me working on incoming's and finals, then office and district frames, and line finder frames, they put me to work on the Sender A. R. T. (automatic relay test) frame. They paired me with Fred Stier, who was a WWII veteran who really knew his stuff. I'll never forget the first time I actually diagnosed and FIXED a defective sender. It was just a flat spring relay that needed adjusting, but once it passed the diagnostic test - repeatedly - I felt like I'd arrived. That first little success gave me confidence and after that I was off and running!
When I was a kid we had telephones like that at home (in a village in NZ in the *1970s*). When they were replaced we ended up with two of them. I found out about the 100 V generator when my dad asked me to "hold those two wires" so that we could test whether the bell in another phone would ring. I made more noise than the bell. Anyway, the two old phones made a nice intercom system.
Seriously impressive. The amount of work required to set up and maintain all of this is tremendous... Hats off to them.
(and now , time to binge watch their channel).
It is wonderful to see all this stuff and to realise the connections between the computer, telephone, teletype and the whole of the 'Information Technology' family. Fabulous!
I joined the Bell System in 1973..became a technician in 1982. Worked inside central offices..in the field and at customer locations. I helped install some of the first fiber optic lines in 1982. Worked in the test center testing phone lines and sending trouble tickets to the outside techs. This old switching equipment was being removed back in the 1980's and replaced by E.S.S. electronic switching systems.
When I was in my early twenties (1979) , my father in law was a maintenance engineer for the then state owned telephone company in Belgium (it was called RTT at that time). He was responsible for the electro mechanical telephone switches around Brussels. When he was on call, I could accompany him several times when he had to do an intervention and oh boy, these switches were impressive. Hundreds of racks spread over several floors , several meters high, full of relais and spinning rotors. What was also impressive was the time it took him to find and solve a problem. Just by listening to the noise he could usually already tell what was wrong. What was also impressive was the backup battery. It was an open lead-acid battery (don't even think of going near it!!!), the size of half a basketball field (well, kinda).
At the age of about 9/10 we had a tour of a local exchange (Watford, UK) with the cub scouts. Late 1960s all mechanical exchange. Absolutely fascinating to me as someone into electrical things - ended up as an electronics engineer. But the big memory for me was the size of the batteries in the basement. An enormous room with an array of batteries, each battery looking like a grey bee hive.
Had some of that equipment as a kid to 'play' with. father would bring home surplus stuff from Manitoba Telephone System (MTS). Pbx, crank phone, dialers ... good times!
Hello, this video made me very happy, because I have serviced these telephone exchanges, from the mechanical P51 system to the digital one. At the time, I was employed here in the operational research and development labs, so it was necessary for me to know all these systems. I will add one piece of information that was not mentioned in the video: The original rotary dials were constructed in such a way that they emitted ten impulses - i.e. each number is a pulse - therefore very often a fundamental problem occurred. If the caller dialed, for example, two ones in quick succession, the switchboard could record it as the number two. The mechanics of the rotary dials were subsequently redesigned and the dial gave two more pulses, i.e. dialing the number one generated three impulses, only the first one was sent to the control panel, the other two served to block a rapid series of impulses in succession, and thus the control panel had enough time to execute the command.
Have a nice day everyone 🙂 Tom
when i was a hippy we learned that "tapping" the phone rest switch on top of public telephones could get you thru free, as long as you were good at "tapping" the pulses to simulate the dial's action, days of phone phreaking, we all knew "secret" codes to dial long distance via engineer's back doors. Later on I worked for Plessy in Brighton, Sussex UK, as a wireman and much later in my company which I founded we won the broadband cable TV and telephony franchise competition from the UK goverment (late 90s), which we promptly sold to Nynex, who sold it to Cable and Wireless, then they sold it to Virgin as it is now - historically before they dug up the streets, we called it Southdown Cablevision Ltd... When my backers, cross country cable of NY came over they went into shock when they saw that all the build was to be underground not on poles.
The amazing thing about telecom is how long these devices can actually last, when they are maintained and monitored by knowledgeable people. Marc, you mentioned starting on the 5ESS switch. I work for one of the "big 3" cell phone companies here in the US, and I too worked on their 5ESS phone switches! That company has only just earlier this year decommissioned their 5ESS switches for their production traffic. However, some of the environmental monitoring cannot be converted to new systems, so some of those 5ESS switches are remaining up and running in limited capacity to serve those monitoring functions even now, in 2022.
The electromechanical panel switch at the museum operated for 51y, though as he noted in the video, there were two people monitoring it at all times.
I would love to visit this museum some day. I've been watching switchboard and switching equipment videos all week...haha
Wow. 13 years in this city and I learn of this just now from my favorite TH-camr! I know where I'm going this weekend!
Ahh I would love to make the trip and see this. Used to be a cable repair man for AT&T. I still love walking the central office and seeing the work of art that those guys created back in the day. Our oldest office still has the 3ESS, 4ESS, 5ESS equipment all retired in place. They now run on a DMS switch. The day is getting closer where they will be powered down. The air pressure systems turned off and all those pulp, pic and filled cables will be retired replaced by fiber.
When I was a kid, our town was wired with lead sheath (paper insulated?) aerial cables which dated back to the late 1920s. Occasionally there would be a fault which was under repair and there would be a gas tank chained to a nearby telephone pole and hose running up to pressurize the cable. Those cables were swapped out for PIC in the 1990s. We now have what are apparently fiber DS-3s running to cream colored ground mounted nodes which tie into the PIC for the last few hundred yards. AT&T sent me a mailer saying fiber to the home is now available, but I don’t know how they provision it. The cable which runs by my house still looks like the old copper cable. We also have whole forest of 5G nodes mounted at the top of telephone poles, one in almost every city block. The 5G units are fed from fiber.
@@wtmayhew Lead stealth cable has paper insulation. Wires were twisted together and hand soldered there was a lot of labor involved. Then the splice cases would be filled with wax. One old timer told me the underground telephone cables were spliced together every 500 ft.
4ESS toll tandem switches and the 5ESS are still in widespread use
My early years involved a 710 tool and large quantities of DeGel... :)
Great nostalgia trip! In 1969, fresh out of USAF, I went to work for South Central Bell as a frameman in the downtown Nashville, TN central office. We still had 4 exchanges of the old Strowger-type switches (242, 254, 255, 256), one crossbar (244), and Nashville’s first ESS (259).
Damn this brings back memories...
Many many bad memories
When I was young(60s), the local exchange was just down the street from me, a beautiful old brick building with big glass windows, and you could see (and hear) the rotary encoders busily working inside. They were open-frame, not covered like the ones you showed, and hung on a huge rack two stories high. I was fascinated, and would have loved to go inside, but the doors were locked with a big NO ADMITTANCE sign. Of course, it was all converted to digital eventually, and the old building fell silent. It was torn down a few years ago, and I mourned its passing. Thanks for showing me this.
Im still barely old enough to remember in the 80s, my grandma used to have a rotary dial phone, yet still used it to call the operator and tell her the name of the person she wanted to talk to. It was only 7 digits to dial a local number, but I guess grandma thought that was still too long on a rotary dial phone, so she just had the operator do it, and she knew the ladies that worked at the phone company so it probably really was quicker. Kinda jealous we dont have that kind of connection with neighbors. imagine just picking up the phone, telling someone you personally know to call the pharmacy staffed entirely by people you went to highschool with.
amazing I could listen to Sarah all day so resourceful!
There's just something magical about the old mechanical systems with lots of moving parts that just isn't there in a fully solid-state semiconductor based world.
There really is. Watching relays, bus bars, solenoids, etc do their thing is so tactile.
Of course, when semiconductors were new, they were the new magical strange thing. Everyone was accustomed to contactors and distributors etc etc, so to have it all happen silently in a tiny box seemed like sorcery.
In a way it’s the same trajectory injection-moulded plastics took, where at first they were new, expensive, and everyone marvelled at their benefits. Then they quickly became cheap, commonplace, throwaway items and people started missing the repairability of wooden chairs, welding holes closed in metal, and indeed in fixing mechanical logic.
We see it with pinball too, not many arcade enthusiasts have much love for modern machines, but pinball still retains a bunch of electromechanical elements even though the control logic running it all has been entirely computerised. And pinball enthusiasts will often have games from the 2010s alongside ones from the 70s.
I own the same Bell Telephone PBX operator’s desk that Lily Tomlin famously used in her skits. This may be my new favorite YT video! I absolutely HAVE TO visit this museum!! Can you imagine the job of having to clean all the contacts in that building?
There is a special place in "heaven" awaiting these curators and volunteers that keep these so very special parts of history running and available.
That brings back 32 years or memories. I was in the long distance #4 Crossbar office. No wonder my eyes are bad replacing relays and all the connections drove me nuts.
3:18 its a current shunt not a fuse!
Fascinated to find this , I worked for a Uk Company who had operations around the world , mostly Brit Commonwealth soI grew up with both GPO and bells system practices. As you say the analogue technology was mind-blowing and expensive , Ericsson crossbar switches were precision made from Phosphor Bronze and copper with gold plated contacts on trunk versions , it wasnt just the cost it was the weight, exchanges/central offices had to be specially re inforced to carry the weight of hundreds of these units.
i was also involved with the development of international direct dialing and the international use of things like toll free 1 800 service.
Thanks so much for bringing back happy memories of untangling the mysteries of call routing, route planning and number assignment in the pre digital world
My lady friend and i were in Seattle several years ago sightseeing. Went t the Boeing museum of flight but didn't know of the Connections museum close by. Being a retired Bell head who worked for PacTel, Southwestern Bell and finally Mountain States Tel co's, i saw and worked with a lot of small CO's as well as the larger ones. Strowgers were used in all the office's i was associated with. My last office was converted to a DMS-100 before 2000. It has previously a 1A switch. My my, the memories. I did construction, splicing, inst. and repair, cable work, teletype, special services work, test center support and finally CO tech. Ma Bell gave me a lifetime of memories. I'm hoping to get up there and visit before...... One last time.
Lovely. I was still working on Strowger exchanges in the mid 90s.
I was on my honeymoon in Seattle two weeks ago and I wanted to visit the Connections Museum…but we didn’t have the time to visit before leaving 😢😩
We’ll definitely plan to visit the next time we’re there!!
Looking at this makes me think of Bletchley Park. If you ever find yourself in the UK you must go there and visit the lovingly restored WW2 computing technology they used to crack German codes. All electromechanical and valve tech.
Tommy Flowers, the designer of Colossus, was a Post Office telecom engineer. He figured he could do a better job and build a faster machine using tubes (valves) rather than relays. He was right.
25 years ago I visited London, the internet was young, I learned data processing in 1978 as a vo-tech class, and never heard of Bletchley Park.. I missed a good opportunity
@@Stache987 Not really sure how much there would have been to see back then. Although it would have been open, the real restoration work wasn't begun until a good few years after you would have been there. Good excuse for a vacation!
@@Tromador thanks for the update 😃
I worked in a telephone exchange in the 1980s with Strowger and later step by step, as well as Ericsson Crossbar and early stored program control switches - we even had a Strowger L&K plunger switch. It's amazing to think we had that in my lifetime!
Absolutely wonderful, Marc! I worked in telco (Plessey) in the '70s and '80s - Strowger, crossbar then a variety of electronic systems here in the UK, and then I worked abroad on Philips and Ericsson systems. Fascinating to see American systems - especially Strowger and crossbar looking very similar to those in the UK. Incredible how quickly things changed in the '70s with the introduction of computer control and then digital technology. It is so important to preserve our technological heritage and keep it operational - all credit to the folks who do this stuff, and thanks for showing us. Wonderful memories.
What a fascinating progression of a technology that we all take for granted. I personally love watching the old bell labs films of the equipment. Tools of telephony is a great watch if you are interested in how it used to be done
Actually have a few bits of the special spanners and adjustors used on those Strowger switches, that I picked up. The spanners fit a lot of electronic parts still, as the patterns are the same as when the first use of them was in telecommunication equipment.
What a beautiful museum! Sarah is awesome!
I worked on building alarm systems in central offices in Kansas in the early 1980's. Some of them still had the old equipment. One guy told me he was sad that an electronic system was going to replace the mechanical system. He said you could tell when the old machine was having a problem and what it was just by the sounds it was making. To me it sounded like a hail storm on a metal roof!
Isn't it amazing that by the time the internet came around, the very thing that created it also removed the need to manually route your connection through each exchange? It's easy to forget how painfully obvious the routing was in the early days because you had to request your connection to the next city or whatever. When you "navigate" the internet or a phone call, you aren't even thinking about having to navigate through the exchanges. Or at least, unless you are on hold and have a moment to take in the scale of the machine connected to your phone. It's all beautifully behind the scenes. Like a good soundtrack to a movie, it compliments the story without being something you really notice too much.
The other thing I take away from this is just how much electricity is used behind the scenes for these large networks. I really do worry about how much energy we spend in our daily lives that we don't even think of. Sure the box that american tooth paste tubes come in is a waste, but what about the 40lb of wasted materials that you never saw? Sure you can make your computer run on 150 watts, but what about the 5kw being used to connect you to a video file on a server somewhere?
I think about that a lot too, the power consumed by telephone exchanges was already enormous but data centres are even bigger. I love your comparison to unseen supermarket shipping waste, it really is very similar. People don’t think about the reams of cling wrap from every pallet, the weight of all the cardboard, the energy of the warehouse pallet forks, etc etc etc.
We’re not trained to see supply chains or networks (of data or people), we’re incentivised to see ourselves as isolated systems. It’s presented as a moral success to appear to reduce some factor (energy, waste, food, whatever) in one’s life even when it just results in pushing that systemic load onto someone else, which can even increase the impact. (One example would be how organic farmers discard more of their crops because of pickier customers in that price bracket, plus crops lost to infestations etc.)
And the internet proved charging for long distance was a farce once all the systems didn't need manual assistance.. what frosts me is IP Telephony charging the recipient of a call a per minute rate, granted it's not like long distance of yesteryear, you paid 3 minutes operator assist, on a direct dial call (minimum), then additional minutes, then they come up with discount rate periods.
@@kaitlyn__L what the buyers of organic food don't realize, is the human being survived (majority] on ordinary food. Personally if gas wasn't ⛽️ a expense to consider, and my store was reasonably priced, I'd be in there more often buying less more frequently, however, like yesterday I had to visit 3 stores to find one that didn't have a empty shelf for a wanted product I use plenty of.. America has become a hoarder lifestyle when it comes to groceries.. what miffs me about this product, in the last 4 years it was $.88 each and since Covid has gone up to $2.08, then yesterday $1.38.. someone's ripping us off.
Illinois Bell to AT&T cable splicing tech here, from 1979 to 2021. When I first started, most central offices (CO's) in my area ( Chicago proper and suburbs) were Crossbar switching equipped, and, for Roselle, which had , some very long subscriber loops which made them use a "C-REG" loop interface system that boosted the line battery to over -80VDC and had packs with the first 2 load coil points built into them. I was on a crew, that, had to install, load coil's on the first 2 load coil points for over 50K subscriber lines, so they could convert that system to a Western Electric 1ESS system with a COSMIC frame, so, we also had to install/rework the mainframe verticals to new protectors that connected to the new frame terminations. As my career went on, all of CO's in the area converted to either a WE, Nortel or Seimens digital switch, some offices like Willowcrest CO ( near Schaumburg) needing to have a new "Schaumburg Main" CO built near the busy Woodfield Mall area to keep up with service demands. It was interesting to be in on the "ground floor, and cable vault" level of building a CO from scratch, and then being involved with the cutover to it.
So you survived the Ameritech era, too! Ohio Bell guy here. That'd been cool to see an office from the ground up.
@@boballmendinger3799 Yes! AND, I even got to work in Ohio, near Columbus ( Dublin area mostly) for December 2000 from what I remember, as I was involved in "Project Pronto" ( Subscriber loop ADSL expansion using the Alcatel LS2000/2021 product) and we had to stop work due to some FCC restrictions, but the Columbus area had tons of money and a lot of cable work to catch up on. All I heard on the conference call was "unlimited overtime" and I packed my bags ASAP.
That's cool! I wondered at the time why Pronto suddenly ceased to exist. Dublin is one of my offices (rover)!
What was cosmic actually? I saw assignment pages on service orders that were assigned by computer if all constraints were met, the biggest hurdle, making a static address system that the customer could give the right info.. it's kind of like here. It's the second floor, the landlord says unit 2 but the credit report and post office say it's apt 2, gracefully we are not served by street delivery, our post office is a third of a mile away and gives any unserved town residents a free small post office box.
Our address management system was called PREMIS. We had to validate a customer address before creating a service order for establishing service. In 4 years of call handling, I had only one time someone could have been social engineering me, they wanted the LEN and the two wire split offs in the field.
@@Stache987 The term "COSMIC" frame, was an acronym, of course, which I forgot, that described a type of "Mainframe" that was supposed to keep jumper runs shorter for frame technicians, and used "punch down" connections instead of solder or wire wrap. Instead of running a jumper from the "Vertical" mainframe (VMDF) which was all the outside plant cable connections, through the ironwork and to the horizontal ( HMDF) where your switch or DS0/DS1 connection blocks were, the VMDF was extended to shorter bays of distribution points where no ladder was needed, and jumpers were then run to the switch or needed DS0/DS1 connection blocks in a trough, or, sometimes through "tie pair" blocks if needed.All I know is, it spread out the VMDF connections to make them harder to find, even if they were marked, and figuring out where the switch OE to make a POTS circuit connection was tough for someone that didn't frequent those types of frames. So, in a nutshell, it simplified, yet complicate some things, only a few suburban offices I visited had that layout, maybe a few remotes, and the one new office I was involved in building in Schaumburg in the late 1980's used regular old VMDF/HMDF layouts.
I'm not in Telco but i've been enthralled with this equipment since i discovered it in 1994
Brings back memories. I started work with telex exchanges in the 70s. Yes I learned to lace cables with linen twine.
My father worked in telco while there was still manual switching. The selectors at 10 mniutes are a memory. Rooms full of banks of cabinets like seen. The noise would move through the room in waves with a background of constant clicking from all over the place.
I was a directory assistance operator and route operator and a toll operator at the beginning of my AT&T career. I retired as a central office technician after 41 years of service.
Every school child should be taken to museums like this.
A truly marvelous collection of historic technology that is obviously being looked after by a great team of people who really care about keeping the old gear alive and working. As a retired signalling & telegraphy engineer living across the big pond in Scotland I really appreciate the museum staff giving working demonstrations on video for those who cannot visit in person. As a HAM radio operator I use radio communications almost every day and watched this video over the fiber ISP connection into the house and gigabit LAN into the shack. It is amazing to think that we can carry a tiny battery powered PBX in our pocket and make SIP calls from almost anywhere these days but without those historic electromechanical systems we would not have the freedom to connect that we enjoy today. Keep up the good work folks. I am sure future generations will appreciate Your dedication to keeping part of the history of telephone communications infrastructure alive.
same here unbelievable labour of love, 73 from Siam too
Really shows why so much early electronic/digital innovation was driven by places like Bell Labs
Your comment made me wonder if anyone is building a museum of early internet-era equipment, SONET & DWDM transmission systems, early routers, from things like Cisco's AGS through the multi-chassis horrors like Juniper's TX Matrix (truly the stuff of nightmares)
Thanks for the tour!
It's sad to think that future technology will never be seen in the same way was vintage tech.
There's a small telephone museum in Ceredigion, Wales, UK (internal fire) which the curator spent years rebuilding. Similar concept, banks of equipment and phones so you can see and hear the clatter of the mechanisms whirring away.
That video was great in the mid 70’s I was a telephone exchange engineer and work on trunk switching exchanges. I installed Strowger exchanges when I started. I also worked in the director rooms now that was loud after 9 hours in there your ears would be ringing and they would be buzzing all evening (long before people used ear defenders). Then I went on to install cross bar system. And final before I went self-employed worked on installing a 5ESS. The engineers who did not work on it were jealous because all the overtime went to this project hence the 5ESS’s nick name was 5 Evenings, Saturday and Sunday
I am so glad you got to see it and the great work they are doing there. Such a great museum.
Thanks for visiting this gem of a museum. 👍
This was very interesting! What a gem to see and you choreographed it very well.
Wow! I'm really impressed! Good job to save tech!
Thanks for the tour.
Special thanks to all those who donated the incredible amount of time and rare equipment to have this living museum preserved !
6:30 That's awesome, thanks for the explanation of the batteries. A few years ago my high school was torn down, and I snuck in to steal whatever I could. One thing I took was a metal box that was mounted to a wall, the inside stated "Battery Replacement Box". It was made by a company that eventually got bought out by IBM.
ITR (international Time Recording)? That may have run the battery for the time correction and or bell signals too. ITR/IBM had systems that could use the room bells for signalling and a separate PBX phone system. The charge controller usually had a minute impulse slave unit that would switch the charge current from cell to cell in a battery to keep them from overcharging. IBM Time equipment was most commonly 24 volts.
Always an inspiration, thanks for the video Marc
I'm so glad youre covering this. I spent an entire day having Ed give me a tour, that place is incredible. I totally got lost in there asking millions of questions!
Wonderful presentation. Much appreciation.
Thank you for showing and sharing all of this wonderful engineering with us
i have never had such an intense desire to go to a museum in my life.
I could spend a week there just watching and listening 🙂 thanks Marc and the museum staff! Dedicated work indeed.
Most excellent! Many thanks for sharing.
brings back good memorizes worked for pacific telephone for 40 years .thanks for the video lineman installer pbx installer switching and fmac thanks again
Wow, just wow. I was geeking hard on that episode - I could have watched hours of that. Thanks Marc!
Yyeeesss!! What a crossover! Thanks Marc for showing off this gem :)
They have some fantastic videos.
Thank you for sharing this video.
Wonderful museum. Thanks for the video tour.
That is really tempting to go see. Thanks for the tour.
Thank you so much for this wonderful video.
Absolutely LOVE this ! THANK YOU
I did my telecommunications apprenticeship on all this stuff ( post office tellecommunications >British Telecom). There is a whole lost art of correct tensions on wipers (strowger) as well as all the setting up of relay contacts as I had to service and replace stwoger wipers and relay contact banks using tension gauges , checking make before brake etc . Not mentioning running jumper wires, cabeling and wireing those up to various contacts. They did not show you the MDF (Main distribution frame) this is where the trunk cabeles arrived and terminated and where you interfaced with the telephone exchange. I worked when Operrators still existed and helped install the new fully automated dialing systems STD (Subscriber Trunk dialling). I can still remeber the unholy nosie of a huge telephone exchange running strowger gear in full flow the smells. Going from that to utter silence when everything upgraded to fully eleconic switching. Yes I am ancient 😩
I recommended the Pavek Museum of Broadcasting and then was a segue to watching a YT video touring the American Precision Museum and now this. Totally awesome! Thanks for sharing as always!
Amazing museum and a fascinating video. Thank you.
I’m subscribed to both your channel and the Connections Museum and admire the rigorous attention to detail in restoring and understanding and operating this equipment which helped carry the information of the years past upon which the technology of today got its start.