Your devotion to this ancient equipment is delightful to see, Sarah - you are truly an angel! I would love to hear audio of actual calls going through your central offices. ( à la Evan Doorbell )
Same here! I would love to visit the museum just to place some calls through Panel, 1XB and 5XB. I do wonder what sort of Tone Plant they also employ, whether that be CDO (probably for the Step CDO they have there) City Tones, or other lesser-known tone plants.
Yeah, I'm glad that someone still owns all this stuff and pays these techs to keep them maintained, and I would love to go through the place in person someday! I wonder how much the admission price is.
I worked in the Anaheim #1 Crossbar Tandem in the late '60s and never thought I would see another working one, ever! We were in the 714 area and basically homed on the 213 area. The office did the billing with the transverters and paper punch recorders to make the tapes to ship to accounting. During the busy time of day the sound of all the senders and markers in the metal cabinets was quite deafening. Probably why I really need my hearing aids now. We had a "Panic Button" mounted above the trouble recorder that had a klaxon horn connected to it. When Western Electric was working in the office and the trouble recorder started spitting out one card after another or the office went totally silent we would push the panic button which meant reattach the last wire you just removed or remove the last wire you just attached to the installers. Sometimes that would restore service, sometimes not. I can remember all the techs rushing to the trouble recorder and grabbing several cards to try and read them to figure what piece of equipment was causing the problem. Our training consisted of about 3 months of class instruction and about 6 months of OJT in the machine to try and get some understanding of how things worked. Sarah, your knowledge and of the equipment and dedication to preserving these machines is quite remarkable to me. Keep up the good work. I left the #1 x-bar to work in the TSPS base unit attached to the Anaheim 4A switch. That was another totally new learning experience. Always something new to learn with Ma Bell. Rick Clark
Being a Crossbar 1 switchman for 20 years, I really enjoyed this video. I retired in 2014 with 40+ years as a COT. I worked on XBar 1,5, ESS, GTD-5 , and fiber optic FIOS but never Panel, although we had a panel office in the building. I wired many Markers in our office, we had 8. I worked in the largest CO in the world at the time, Newtown CO in Elmhurst Queens NY.The wires on each bay were cut for TAX reasons. The company was taxed for every working frame, by cutting the cables/wires the switch was considered RIP "retired in place" and no longer taxable. I did a lot of cutting my last few years with the company as the new technology was coming on line. We could have used you back in the day, you are very knowable. The XBar prints were big sheets of paper, also had "detached contact" prints in 17x11" book form. I enjoyed the hands on trouble shooting down to the component level, now it is just change a PCB. Thanks for the videos.
Right, I said the wrong thing when I said "insurance". I was corrected by a friend afterwards that it was actually tax reasons. We still have some of the orange RIP stickers on the frames, where they marked them as retired. Thanks :)
I love that this vintage technology is being preserved! I was just a grade school age kid in the '60s when dad first gave me a tour of the 1xb office where he worked. I remember it all so vividly. If I'm not mistaken, you now have the only working 1xb left in existence. Excellent work! And keep them videos coming! I love 'em!
I've watched this video at least three times. Every time I hear the phone ring towards the end I get this strange sense of elation. I love how you produced the video. I admire you for your hard work and dedication. I'm certain the term 'labor of love' is a gross understatement. I'm blown away by your ability to take some gnarly complicated stuff and expain it in basic and understandable concepts and operations. Thank you!
I remember playing with the phone as a kid in a really large area code served by crossbar switches. I avoided "boxing" since Bell was taking that seriously but had lots of fun just checking out the local systems and all the cool sounds it made. All the pulsing between switches and the cadence and sound of the various tones. No one would bother you if you didn't call "0" or "611" which were the only numbers that knew where you were. I had decent recording equipment and the means to impedance match in and out of the phone line into audio equipment, but I don't think I kept any recordings. After I went away to college I got home and the whole phone network was very silent and clean sounding. It had been replaced with ESS and all my favorite sounds were gone forever. Before that we did ride our bikes up to an exchange and banged on the door and a friendly tech showed us around. Well not the first time but we persisted on different days until we found a tech in a good mood. Just don't touch anything! It was a crossbar in the afternoon and it was LOUD!
Joseph Ruther mentioned -48V stings - It reminded me that it's ring voltage you need to worry about, something I learnt the hard way as a 13yo putting an extension in for my grandparents & thinking "I'll ring the line from my mobile whilst holding the line wires together to test I've done it right" The phone rang correctly. I learnt that ring voltage hurts. I did not forget that lesson...
I did something equally stupid when I was a kid. I was holding the tip and ring in my mouth while messing with the connecting block outside my house. Then the phone rang. :(
It's amazing seeing this working. I really respect your passion for this old equipment. Thanks for these videos. I feel it deeply when you describe "destroying" equipment to write it off. It is so heartbreaking to see sometimes. I've seen some very low-operating-hours equipment destroyed for similar reasons. Some of it was not simply cut wiring; it was removal of lubricant and running to destruction, or removing protection devices and running until the electrical windings were melted.
@@ConnectionsMuseum There's so much of that destruction which goes on. So disappointing! We need to continue learning about the origins of things we still have today. Otherwise, people will not appreciate what went into them. I have a thing for older industrial equipment as well, but mainly refrigeration and power / electric motor stuff. Not nearly as technically sophisticated as yours, however, there're very few people who seem to care about it. Please keep up the great videos! Looking forward to seeing the next one soon!
Thanks for all of this, Sarah! You do an excellent job of describing the functioning of the equipment. And you recognize how some of us were so intrigued by the sounds of the equipment when we used it, many years ago. Keep it up!
I was a teenage phreaker and built blue, black and red boxes, and I was not afraid to use them. I didn't know what was going on. I was also shown around the inside of a number 5 crossbar central office by a friendly central office technician,. Also engaged in a lot of dumpster diving, found a bunch of old relays and a bunch of trouble recorder punch cards. All of your videos are fantastic Sarah, thanks for the great work.
Alright, Sarah, now that I've watched the entire video, I can say that I appreciate you touching on the subject of all the destructive wire cutting involved when it came time to decommission this equipment. I could have seen the decommissioning of dad's 1xb, 5xb, and TSPS but instead chose (wisely) to just stay away n "remember it the way it was". BTW I think your museum videos are very representative of what this equipment "sounded" like in the wee hours of the morning when call volumes were at their minimum. I like your wire tracing technique too, but 48 volts can poke a bit if you latch into it. Can't help but wonder if you ever get poked! . . .
LOL! Hey, from one vintage technology geek to another, I salute you! Take this to heart: You're only dealing with 48vdc n back emf from relay coil circuits opening. My own passionate hobby is vacuum tube electronics. Vintage tuners n amps. I've been poked by 400vdc and lived to talk about it. The experience is very over-rated and I certainly do not recommend it! 8D But I love my Bell Sound Carillon 6060 amp n matching 6070 tuner and I do all my own work on these n everything else I have. You're not a true technician until your vintage pride and joy has poked you! 8D
@@ConnectionsMuseum 60/90 Tip/Ring is just enlightening. I've tangled with PBX and hotel/motel boards before, and they would sit me on my ass when someone would call in. I'd be sitting there cussing a short streak (I'm a lightning magnet, don't get close to me during a storm), then get back up, dust myself off of any carbon I created during the zap, and keep on sorting out the spaghetti works that is the wiring.
@Joseph Rutha Good Move it was not happy. I've seen grown men with tears running down their faces when the Panel offices were cut. Each Exchange had a Soul and a mood of their own. Late night you would hear the interrupter bay keeping beat and hear the calls routing one by one. Mother's Day it was a din!
This video series brought back some memories of my early phone career, I started in 1970 in a Panel and Number 1 XB office in Oakland California. Within 6 years No. 1 ESS came online. Such memories
From a retired SxS switching tech : This is awesome. Always wanted to work crossbar. Have been studying crossbar #1 and panel for some months now off of the archive site. Thank you Sarah. From t1dm-ted.
Hello. I was wondering how SxS switches were interfaced to trunks using MF signalling. I have been curious about this for years and have never found anyone to ask. Thanks.
@@bsadewitz once a SxS switch hunts to an idle trunk, the relays in the trunk circuit will connect a transformer via 4-wire - transmit And receive pairs. Then to a E signaling unit which uses e&m signaling which toggles 2600 cycle tone on and off according to the dial pulses which interfaces into a carrier system to a distant central office, such as N2, O, or T carrier systems.
There are converter trunks from dial pulse to MF but the distant office will usually translate that, according to where the call is going to. Interesting stuff. I'm 70 but still would work these systems given the chance. I worked southwestern bell in the 70's as a switchman and loved it in Eldon Missouri.
So basically you were augmenting the relay logic needed to support phone connections to the new exchange. The whole system is amazingly complex but you do a great job of explaining it. Thank you for that!!! There are so many individual pieces like the crossbar switch that someone had to think of, and then developing the relay logic needed to provide basic functionality. My ADD brain wants to liken it to a great big old fashioned pinball machine. Where a specific input gets you a specific output. Thanks for taking the time to explain the components and for the time you spend off-camera repairing components and reconnecting parts of the frames.
I was a WECO installer 212 NYC early 1970's. I have worked on >everything in your museum. I remember well the reverence that was paid to the testers and specialists in their areas. The second liners knew their names. All the men respected them! Then there is Sarah. I never knew anyone with the rounded out knowledge as you with ALL the switches. Looks like the second liner is buying lunch and of course we will get someone to carry your tools to and from your big Plymouth sedan:~} Ya that smart!
I want to build a see-and-say for my future children that teaches them the sounds of switching equipment. "The marker connecting the call and dropping out goes 'Ta-dah-duh'".
Sarah, several times during the winter when a storm is in progress and you go to make a call and after picking up the handset and there is not dial tone just side tone. So many calls are in progress, that there is no open lines. All you hear is battery voltages and background noises, clicks and pops.
That note at the end that this switch is fully able to route the call without this needless loop over to itself is a great point at the differences between "real" installations in a world wide telephone network, vs a museum with just a handful of switches at hand. It is hard enough to get enough use out of just 1 of the machines on display, let alone the verity of them. So one has to make up demonstrations for how things could have worked, it becomes like theater. One switch playing the role of many offices spread out in a larger area. And I guess the designers of this switch did the very same thing back in the day during its development. Since testing a machine's various features is usually less headache inducing when done in isolation. And one won't be a nuisance to others in the process.
Excellent video. I love the alligator clip idea. The really makes the trial connections so much easier to reconfigure is its not right. Thanks for the video.
I enjoyed the video enormously. It would be good to have an introductory overview with some high level conceptual illustrations to put everything into context. Based in England I am familiar with tandem switching, crossbar concepts and marker use (eg on uniselector PAXs) but a picture of the route of the call setup would be a big bonus. 😉. I think that I have grasped the test desk concept of checking that the marker knows all it needs to because key relays have essentially a check contact - simple but clever. A talk with high level diagrams for the test desk would be super. You are a star!
Welcome back, missed your videos. I always appreciate your dedication to explaining and maintaining this vintage equipment. One day if possible, I'd like to hear those additional signaling sounds you talked about at 22:22 maybe along with an explanation of what those sounds means. Thanks
I help construct crossbar and Strowger exchanges back in the 70s working for plessey telecommunications I remember that the crossbar racks were very heavy to lift up and install System X was just coming out when I left in 1980 to join the GPO
My son is 6 years old and would love to visit the museum, problem is I know he wouldn't be able to keep his hands to himself. Visited a couple years ago and spent hours there. Thanks for all the videos
You have the most awesome job. I love to hate the sometimes antiquated broadcast equipment I work on but it always amazes me to see what they could pull off with minimal silicon and they had to be bullet proof. I see the same thing in this gear. Built like a tank and with style things designed by machine just don't have. If it was doing all of that with just relay logic that was so ahead of its time and almost a lost art now. Microprocessors are so easy now a kid can do it literally. This well I say it like the stuff I work on its a mix of tech, skill, art and some voodoo that is a steep learning curve but eventually it starts talking to you. My hats off to you for mastering it. I would love to see this thing in action one day but I totally have to get a look at those schematic drawings.
One of the things I love about the museum is that all of us are volunteers. It may seem like a job, but we are all here on our free time because we love this stuff. We use several microcontrollers around the museum to do small jobs here and there. It’s crazy that I can buy a pile of ESP8266 dev boards and if one breaks, I just pull another one out of the drawer. But working with them is nowhere near as fun or satisfying as this equipment. The amount of thought and human engineering that went into these machines is incredible. Design like this is indeed a lost art.
Oh yeah. The learning curve is super steep. They had their own language and it took me a year or so just to get familiar with it. I worry that all of this knowledge will be lost some day so I try to share as much of what I’ve learned as possible. We’ve got over a million pages/sheets of schematics. Some of them are scanned, so if there is something in particular that you want to see, let me know. I might be able to upload it somewhere.
@@ConnectionsMuseum My job is a dying breed. The RF engineer. It got put on me originally the IT guy after one of the engineers passed away and the other had to retire. Most I know that are still in the line of work are twice my age (I am in my early 40s) and well its going the way of the computer and VCR. The new solid state units is just swapping modules and the on screen display tells you what to do. They have only recently been able to produce the power with the reliability of a tube transmitter mainly shrugging off lightning. The old tube transmitters you have to manually tune and its as much science as art as feel you are watching a half dozen meters and when you are in tune its not so much what the meters say but how they act. The newer ones have processor control and will shut down before you damage something... usually but still can be dangerous to be around much less working on. It only gets more complex from there. The stuff from the cold war days was extra hardened and somehow ran mostly on contactors and relays. It's where I first saw wire lacing and learned to do it myself by duplicating it. I saw you doing it in another video. If I ever make it to that area I will have to see that equipment operating and if I can see a schematic at the same time I can probably follow individual components but the overall schematic I am guessing is a lot bigger than what I work on and that usually takes up a big binder even then I only look at the zoomed in schematic for the section I am working on and that is something about the size of 3 or 4 rack cabinets side by side. The solid state ones are about the size of a single rack or a refrigerator and so efficient over the tubes they will pay for themselves pretty quickly in power consumption. Tech just is evolving so fast. I was watching a video on the Long Lines microwave sites and how huge that equipment was. Now I have a wisp on my towers all over the region and I think they are moving gig speeds through equipment you can lift with one hand and costs a few hundred to a few thousand dollars. Changes so fast and old tech gets pushed aside. Without people like you preserving it and people like both of us learning as much as we can from the few people left that know it and the notes of those before them it would all be lost to the past.
I am working through videos right now. First, you are an excellent person to communicate this information. You care, are clear, and passionate. That alone makes the whole thing worthwhile. Art? YES! It is amazing to me to understand a completed call is an actual closed circuit! Crazy cool. I hear hints of this exchange being able to talk to the outside world. I hope that happens, or at least to other network bits still being maintained for whatever reasons. I am sure it has been asked, but I will again anyway, is there any possible value to having some subscribers? Probably not. The thing I find most memorable, in addition to the many cool sounds one used to hear, is the audio quality. Sure, bandwidth was not all that great, but the simplicity of the system electrically, along with the often robust materials used, made it accurate! Hearing people is a compelling experience. I should not write this, but I once worked with a woman and we both were married, both found each other attractive, but also both unwilling to really act on that knowing better what a mess like that possible is like. So we had fun. One day, she put a little perfume in the handset, and when I would take a call, there it was! Hilarious! Then she called and did that ASMR thing, clicking tongue, and thebother sorts of stuff ASMR is well known for today. The old gear conveyed all that properly and I had a full response! Tingles everywhere, and I have to say nothing modern, except for the high definition calls made possible when all parties on a call have compatible cellular phones, can compete! The ultra aggressive lossy compression eats away at the very soul of a call thus turning it into something functional, but no more than that. And when I have an opportunity to consider older tech of all kinds, it seems universally true each tech type will have a thing it does with excellence. And we can replace it, sure. But the cost is that excellence. Doesn't make the replacement unworthy or bad. It isn't. But there is that bit we will invariably miss and the fuel of nostalgia is delivered right to a vein to be appreciated proper. Maybe I can get a tour one day and place a call and talk to someone. Would live to hear that intimate speech again. Makes one appreciate people, what talking really is and how it can make us feel. Thank you for donating your time. Maybe one day it can be a job. I think it should. Keeping older tech alive has merits. We never quite know when mining the work of our past may yield insight of some kind.
Interesting stuff. I worked on a UK crossbar exchange. It was a development of a French system. Quite different from that. There was a rival system in the UK which looks a bit more like that. It took a few years to get to grips with crossbar. I remember registers, line units, group units, markers, translators, incident recorder etc. All scrapped many years ago. I don't know if any went to a museum.
This brings back to mind a question I've had for years. (WHO, or WHAT) is the supervisory power that tells the "Central Office" to add a NEW PREFIX? (The Bell System)? And how many prefixes can you add to the #1 Crossbar? Obviously it has to be a prefix that doesn't already exist within your Area Code... but, HOW is it decided what the new prefix will be? ... 949...885...623?
@Sarah -- where/how did you learn all this? You have a tremendous amount of knowledge of switches and terminology. I'd love to hear how you came by all of it...
Maybe I'll do a video on that someday. One (partial) answer is that these switches needed serious maintenance when I got to the museum. A really effective way to learn a system is to have to repair it. By solving problems, I'm forced to work through the logic of the machine, and deal with whatever comes up. Much better to learn that way, than to explore a fully working system.
Corporate bureaucracy at its finest. Expected nothing less from AT&T. :-) But really cool that you hook things together like it would have been done in the real world, rather than just essentially making it a basic demonstration. And I like how simple it is to add a new route to the marker - just a couple of jumper wires and youre done! Fantastic engineering.
Loving these videos and currently working my way through all of them for no particular reason other than being a geek and finding them really interesting! I was wondering with the compensating resistance values, are there a discrete set values to choose from or was it a case of measuring the actual line characteristics and setting a bespoke value for every trunk?
Thanks! The compensating resistance values come in discrete steps of 300 ohms, so 0, 300, 600, 900, etc. You can find a value that works for any local trunk using those increments.
do you think you can make a video showing the sounds on the subscriber line (click, clanks, and tones) and pointing out what parts of the switch are actually making those sounds with the call progression?
Surprised those CCFs are solder terminals and not wirewrapped. Does anyone know when Bell/WE started doing wirewrap and moved away from soldering the CCFs?
Not sure what a CCF is. The first mention of wirewrap is in the 1951-07 Bell Labs Record "Mechanically Wrapped Connections" www.telecomarchive.com/docs/bsp-archive/BLR/29-7.pdf
There are working exchanges on display at avoncroft museum, Milton Keynes museum, amberly chalk pits, dean forest railway, and a handful of other places. Hope you get a chance to visit some of them!
This is great video, brings me a lot of good memories working with Ericsson, NEC and Siemens crossbar switches. Did you have any videos on rotation switches?
Thats correct. By the way, panel switches have "decoders". Crossbar switches have "markers". They are indeed different, but play a similar role in call completion.
Sarah: do you know of the user Evan Doorbell on here? He has what must be the most exhaustive series on analog phone exchange sounds! If it either made, carried, transferred, or accepted a phone call, it's in one of his uploads. Just thought I'd share that resource. "Make a note of it" as the late Jane Barbe famously recorded!
I didn't think of that, but its true! Markers are full of things like that. I call them "gating" statements, but that's not really an official word. It's just something that I came up with. They function like an assert, and they establish check-and-stop points to safely exit with an error if something goes wrong. (You wouldn't want a $20,000 marker to hang indefinitely!
I learn first by doing, then by reading about what I just did. I am sort of obsessive, and have a very good memory for this kind of stuff. We have the books, and the machines, so I can make the machine do something, and then read the book to figure out why it did that :) The #1 and #5 both used crossbar switches, but the layout of the machine is very different. It's sort of like asking "whats the difference between a semi truck and a family car?" Both have wheels, but their purpose is very different! The 1XB is the semi truck of switches. It's huge and powerful but not that great at going around sharp corners. The 5XB is the family car of switches. Not as much raw power as a 1XB, but it can easily get in and out of a tight spot, and its more comfortable to sit in!
Me, towards the end of the video: I should ask if there is something I can read for the basics, because I don’t know things, like tandem Sarah: ... so this is what tandem switching is...
I've been able to dial the panel switch on CNET. PArkway 2-5118 is a good test as it gives you a flashing busy. Although connectivity seems to be unreliable sometimes.
In the early days of Xbar-1 we had to photograph all the zone registers and send the films to accounting, then along came Vidar, a magnetic tape, reel to reel recording system. We had to remove the tapes every morning and send them to accounting.
There weren't many women working on switches like this in the 1970's women were just coming in as techs and didn't have an easy time asthma was an all male dept. He
The lack of simple jargon definitions dilutes the presentation. Imagine you're not talking to another familiar with the terminology. A quick slide covering the call setup and control flow would really help get the concepts across when you're then walking through the signal flow at the equipment. We need a "map" to follow you easier.
Thanks for the feedback. I'll try to do that sometime. For now, this will have to be enough: telephonecollectors.info/index.php/browse/bc-switching-library/western-electric/weco-switching-documents/weco-crossbar/11743-we-1-xbar-completion-of-a-call-bulletin-2-5-1-oct39 and en.wikipedia.org/wiki/Number_One_Crossbar_Switching_System
I can't even begin to understand why any timely, purposeful upgrade would involve insurance. Why would removing stuff like this from service just for an upgrade have anything to do with an insurance claim at all? Secondly, why would insurance demand that a failure be purposefully manmade and not consider that insurance fraud? Geeze, I don't get to purposefully crash my vehicle just so I can claim a total loss, do I? I heard you say "writing it off the books." But why is that an insurance thing rather than what I'm used to hearing: a tax thing, and then why should they feel like they have "lost more money" just because of if the owner had not destroyed the machines, even though they wouldn't have lost more money? In the auto insurance industry, consumers actually get to sell a vehicle that was already totaled! Reserving the salvage right. The insurance co. doesn't deduct much and I've done it; it's pretty cool that I can actually keep the money minus a little, AND the vehicle! So if they allow this in auto insurance, then what's the problem with something similar here?
This was required by the IRS to be able to take it off the taxable inventory list. The TELCO'S would not spent the time and money if it was not required.
Your devotion to this ancient equipment is delightful to see, Sarah - you are truly an angel!
I would love to hear audio of actual calls going through your central offices. ( à la Evan Doorbell )
Same here! I would love to visit the museum just to place some calls through Panel, 1XB and 5XB. I do wonder what sort of Tone Plant they also employ, whether that be CDO (probably for the Step CDO they have there) City Tones, or other lesser-known tone plants.
Yeah, I'm glad that someone still owns all this stuff and pays these techs to keep them maintained, and I would love to go through the place in person someday! I wonder how much the admission price is.
Sing a long.
"Stupid
Bloody
Cross - bar
What
A
load
of Sh.t"
Anyone who spent time in a NEC X-bar will be able to sing a long. :)
I worked in the Anaheim #1 Crossbar Tandem in the late '60s and never thought I would see another working one, ever! We were in the 714 area and basically homed on the 213 area. The office did the billing with the transverters and paper punch recorders to make the tapes to ship to accounting. During the busy time of day the sound of all the senders and markers in the metal cabinets was quite deafening. Probably why I really need my hearing aids now. We had a "Panic Button" mounted above the trouble recorder that had a klaxon horn connected to it. When Western Electric was working in the office and the trouble recorder started spitting out one card after another or the office went totally silent we would push the panic button which meant reattach the last wire you just removed or remove the last wire you just attached to the installers. Sometimes that would restore service, sometimes not. I can remember all the techs rushing to the trouble recorder and grabbing several cards to try and read them to figure what piece of equipment was causing the problem. Our training consisted of about 3 months of class instruction and about 6 months of OJT in the machine to try and get some understanding of how things worked. Sarah, your knowledge and of the equipment and dedication to preserving these machines is quite remarkable to me. Keep up the good work.
I left the #1 x-bar to work in the TSPS base unit attached to the Anaheim 4A switch. That was another totally new learning experience. Always something new to learn with Ma Bell. Rick Clark
That’s really great. Basically, you had a big red “undo” button :)
Being a Crossbar 1 switchman for 20 years, I really enjoyed this video. I retired in 2014 with 40+ years as a COT. I worked on XBar 1,5, ESS, GTD-5 , and fiber optic FIOS but never Panel, although we had a panel office in the building. I wired many Markers in our office, we had 8. I worked in the largest CO in the world at the time, Newtown CO in Elmhurst Queens NY.The wires on each bay were cut for TAX reasons. The company was taxed for every working frame, by cutting the cables/wires the switch was considered RIP "retired in place" and no longer taxable. I did a lot of cutting my last few years with the company as the new technology was coming on line. We could have used you back in the day, you are very knowable. The XBar prints were big sheets of paper, also had "detached contact" prints in 17x11" book form. I enjoyed the hands on trouble shooting down to the component level, now it is just change a PCB. Thanks for the videos.
Right, I said the wrong thing when I said "insurance". I was corrected by a friend afterwards that it was actually tax reasons. We still have some of the orange RIP stickers on the frames, where they marked them as retired. Thanks :)
I love that this vintage technology is being preserved! I was just a grade school age kid in the '60s when dad first gave me a tour of the 1xb office where he worked. I remember it all so vividly. If I'm not mistaken, you now have the only working 1xb left in existence. Excellent work! And keep them videos coming! I love 'em!
I grew up in the 1970s, and strange telephone tones/rings/etc was always cool. Your dedication is inspiring! Thanks so much for the tours/lessons.
I've watched this video at least three times. Every time I hear the phone ring towards the end I get this strange sense of elation. I love how you produced the video. I admire you for your hard work and dedication. I'm certain the term 'labor of love' is a gross understatement. I'm blown away by your ability to take some gnarly complicated stuff and expain it in basic and understandable concepts and operations. Thank you!
I remember playing with the phone as a kid in a really large area code served by crossbar switches. I avoided "boxing" since Bell was taking that seriously but had lots of fun just checking out the local systems and all the cool sounds it made. All the pulsing between switches and the cadence and sound of the various tones. No one would bother you if you didn't call "0" or "611" which were the only numbers that knew where you were. I had decent recording equipment and the means to impedance match in and out of the phone line into audio equipment, but I don't think I kept any recordings. After I went away to college I got home and the whole phone network was very silent and clean sounding. It had been replaced with ESS and all my favorite sounds were gone forever.
Before that we did ride our bikes up to an exchange and banged on the door and a friendly tech showed us around. Well not the first time but we persisted on different days until we found a tech in a good mood. Just don't touch anything! It was a crossbar in the afternoon and it was LOUD!
Your knowledge base blew my mind. Im hooked! Thank you for your devotion to this project.
Joseph Ruther mentioned -48V stings -
It reminded me that it's ring voltage you need to worry about, something I learnt the hard way as a 13yo putting an extension in for my grandparents & thinking "I'll ring the line from my mobile whilst holding the line wires together to test I've done it right"
The phone rang correctly.
I learnt that ring voltage hurts.
I did not forget that lesson...
I did something equally stupid when I was a kid. I was holding the tip and ring in my mouth while messing with the connecting block outside my house. Then the phone rang. :(
It's amazing seeing this working. I really respect your passion for this old equipment. Thanks for these videos.
I feel it deeply when you describe "destroying" equipment to write it off. It is so heartbreaking to see sometimes. I've seen some very low-operating-hours equipment destroyed for similar reasons. Some of it was not simply cut wiring; it was removal of lubricant and running to destruction, or removing protection devices and running until the electrical windings were melted.
Yeah, its terrible to think about. Really bugs me that so much amazing stuff was destroyed in one way or another!
@@ConnectionsMuseum
There's so much of that destruction which goes on. So disappointing! We need to continue learning about the origins of things we still have today. Otherwise, people will not appreciate what went into them.
I have a thing for older industrial equipment as well, but mainly refrigeration and power / electric motor stuff. Not nearly as technically sophisticated as yours, however, there're very few people who seem to care about it.
Please keep up the great videos! Looking forward to seeing the next one soon!
On a simpler note, "I love the smell of hot solder flux in the morning!"8D
Thanks for all of this, Sarah! You do an excellent job of describing the functioning of the equipment. And you recognize how some of us were so intrigued by the sounds of the equipment when we used it, many years ago. Keep it up!
I was a teenage phreaker and built blue, black and red boxes, and I was not afraid to use them. I didn't know what was going on. I was also shown around the inside of a number 5 crossbar central office by a friendly central office technician,. Also engaged in a lot of dumpster diving, found a bunch of old relays and a bunch of trouble recorder punch cards. All of your videos are fantastic Sarah, thanks for the great work.
Alright, Sarah, now that I've watched the entire video, I can say that I appreciate you touching on the subject of all the destructive wire cutting involved when it came time to decommission this equipment. I could have seen the decommissioning of dad's 1xb, 5xb, and TSPS but instead chose (wisely) to just stay away n "remember it the way it was". BTW I think your museum videos are very representative of what this equipment "sounded" like in the wee hours of the morning when call volumes were at their minimum. I like your wire tracing technique too, but 48 volts can poke a bit if you latch into it. Can't help but wonder if you ever get poked! . . .
I get zapped constantly. I did a few times while making the video, but I cut it out in the final edit. ;)
LOL! Hey, from one vintage technology geek to another, I salute you! Take this to heart: You're only dealing with 48vdc n back emf from relay coil circuits opening. My own passionate hobby is vacuum tube electronics. Vintage tuners n amps. I've been poked by 400vdc and lived to talk about it. The experience is very over-rated and I certainly do not recommend it! 8D But I love my Bell Sound Carillon 6060 amp n matching 6070 tuner and I do all my own work on these n everything else I have. You're not a true technician until your vintage pride and joy has poked you! 8D
@@ConnectionsMuseum 60/90 Tip/Ring is just enlightening. I've tangled with PBX and hotel/motel boards before, and they would sit me on my ass when someone would call in. I'd be sitting there cussing a short streak (I'm a lightning magnet, don't get close to me during a storm), then get back up, dust myself off of any carbon I created during the zap, and keep on sorting out the spaghetti works that is the wiring.
@Joseph Rutha Good Move it was not happy. I've seen grown men with tears running down their faces when the Panel offices were cut. Each Exchange had a Soul and a mood of their own. Late night you would hear the interrupter bay keeping beat and hear the calls routing one by one. Mother's Day it was a din!
@@ConnectionsMuseum I can imagine that on the final...."...from my subscriber line to my district.....OW! SHIT!"
This video series brought back some memories of my early phone career, I started in 1970 in a Panel and Number 1 XB office in Oakland California. Within 6 years No. 1 ESS came online. Such memories
Always fascinating seeing complex logic being implemented by relays. Thanks for the walkthru.
From a retired SxS switching tech : This is awesome. Always wanted to work crossbar. Have been studying crossbar #1 and panel for some months now off of the archive site. Thank you Sarah. From t1dm-ted.
Hello. I was wondering how SxS switches were interfaced to trunks using MF signalling. I have been curious about this for years and have never found anyone to ask. Thanks.
@@bsadewitz once a SxS switch hunts to an idle trunk, the relays in the trunk circuit will connect a transformer via 4-wire - transmit And receive pairs. Then to a E signaling unit which uses e&m signaling which toggles 2600 cycle tone on and off according to the dial pulses which interfaces into a carrier system to a distant central office, such as N2, O, or T carrier systems.
There are converter trunks from dial pulse to MF but the distant office will usually translate that, according to where the call is going to. Interesting stuff. I'm 70 but still would work these systems given the chance. I worked southwestern bell in the 70's as a switchman and loved it in Eldon Missouri.
But these systems are all gone except for SxS Phil's or the connection museum.
@@bsadewitz of course if you were dialing a 1+ call, the ani (automatic number identification) System would outpulse to the distant office.
So basically you were augmenting the relay logic needed to support phone connections to the new exchange. The whole system is amazingly complex but you do a great job of explaining it. Thank you for that!!! There are so many individual pieces like the crossbar switch that someone had to think of, and then developing the relay logic needed to provide basic functionality. My ADD brain wants to liken it to a great big old fashioned pinball machine. Where a specific input gets you a specific output. Thanks for taking the time to explain the components and for the time you spend off-camera repairing components and reconnecting parts of the frames.
I was a WECO installer 212 NYC early 1970's. I have worked on >everything in your museum. I remember well the reverence that was paid to the testers and specialists in their areas. The second liners knew their names. All the men respected them! Then there is Sarah. I never knew anyone with the rounded out knowledge as you with ALL the switches. Looks like the second liner is buying lunch and of course we will get someone to carry your tools to and from your big Plymouth sedan:~} Ya that smart!
LOL, thank you! I'm in debt to all of the smart people who saved all of this equipment, and taught me how it works. Glad you liked the video :)
I want to build a see-and-say for my future children that teaches them the sounds of switching equipment. "The marker connecting the call and dropping out goes 'Ta-dah-duh'".
Holy crap! The complexity is astounding!
Loved that. I find these devices truly beautiful. The engineers of the older days were super talented.
I so much want to visit the museum after this whole pandemic is over. Really love old tech
Sarah, several times during the winter when a storm is in progress and you go to make a call and after picking up the handset and there is not dial tone just side tone. So many calls are in progress, that there is no open lines. All you hear is battery voltages and background noises, clicks and pops.
That note at the end that this switch is fully able to route the call without this needless loop over to itself is a great point at the differences between "real" installations in a world wide telephone network, vs a museum with just a handful of switches at hand. It is hard enough to get enough use out of just 1 of the machines on display, let alone the verity of them. So one has to make up demonstrations for how things could have worked, it becomes like theater. One switch playing the role of many offices spread out in a larger area.
And I guess the designers of this switch did the very same thing back in the day during its development. Since testing a machine's various features is usually less headache inducing when done in isolation. And one won't be a nuisance to others in the process.
God... I used to work for AT&T. I loved having access to all of the tech documentation and the old guys to talk to about this stuff.
Excellent video. I love the alligator clip idea. The really makes the trial connections so much easier to reconfigure is its not right. Thanks for the video.
ds99 what is c*net , and how does it work?
Bryan Frechette Do you have the wrong person? I don’t know what that is.
good job in explaining the # 5 CXPX
I enjoyed the video enormously.
It would be good to have an introductory overview with some high level conceptual illustrations to put everything into context.
Based in England I am familiar with tandem switching, crossbar concepts and marker use (eg on uniselector PAXs) but a picture of the route of the call setup would be a big bonus. 😉.
I think that I have grasped the test desk concept of checking that the marker knows all it needs to because key relays have essentially a check contact - simple but clever. A talk with high level diagrams for the test desk would be super.
You are a star!
I have wondered about this since like 1996! I'm stoked.
Welcome back, missed your videos. I always appreciate your dedication to explaining and maintaining this vintage equipment. One day if possible, I'd like to hear those additional signaling sounds you talked about at 22:22 maybe along with an explanation of what those sounds means. Thanks
I help construct crossbar and Strowger exchanges back in the 70s working for plessey
telecommunications I remember that the crossbar racks were very heavy to lift up and install System X was just coming out when I left in 1980 to join the GPO
My son is 6 years old and would love to visit the museum, problem is I know he wouldn't be able to keep his hands to himself. Visited a couple years ago and spent hours there. Thanks for all the videos
You have the most awesome job. I love to hate the sometimes antiquated broadcast equipment I work on but it always amazes me to see what they could pull off with minimal silicon and they had to be bullet proof. I see the same thing in this gear. Built like a tank and with style things designed by machine just don't have. If it was doing all of that with just relay logic that was so ahead of its time and almost a lost art now. Microprocessors are so easy now a kid can do it literally. This well I say it like the stuff I work on its a mix of tech, skill, art and some voodoo that is a steep learning curve but eventually it starts talking to you. My hats off to you for mastering it. I would love to see this thing in action one day but I totally have to get a look at those schematic drawings.
One of the things I love about the museum is that all of us are volunteers. It may seem like a job, but we are all here on our free time because we love this stuff.
We use several microcontrollers around the museum to do small jobs here and there. It’s crazy that I can buy a pile of ESP8266 dev boards and if one breaks, I just pull another one out of the drawer. But working with them is nowhere near as fun or satisfying as this equipment.
The amount of thought and human engineering that went into these machines is incredible. Design like this is indeed a lost art.
Oh yeah. The learning curve is super steep. They had their own language and it took me a year or so just to get familiar with it. I worry that all of this knowledge will be lost some day so I try to share as much of what I’ve learned as possible.
We’ve got over a million pages/sheets of schematics. Some of them are scanned, so if there is something in particular that you want to see, let me know. I might be able to upload it somewhere.
@@ConnectionsMuseum My job is a dying breed. The RF engineer. It got put on me originally the IT guy after one of the engineers passed away and the other had to retire. Most I know that are still in the line of work are twice my age (I am in my early 40s) and well its going the way of the computer and VCR. The new solid state units is just swapping modules and the on screen display tells you what to do. They have only recently been able to produce the power with the reliability of a tube transmitter mainly shrugging off lightning. The old tube transmitters you have to manually tune and its as much science as art as feel you are watching a half dozen meters and when you are in tune its not so much what the meters say but how they act. The newer ones have processor control and will shut down before you damage something... usually but still can be dangerous to be around much less working on. It only gets more complex from there. The stuff from the cold war days was extra hardened and somehow ran mostly on contactors and relays. It's where I first saw wire lacing and learned to do it myself by duplicating it. I saw you doing it in another video. If I ever make it to that area I will have to see that equipment operating and if I can see a schematic at the same time I can probably follow individual components but the overall schematic I am guessing is a lot bigger than what I work on and that usually takes up a big binder even then I only look at the zoomed in schematic for the section I am working on and that is something about the size of 3 or 4 rack cabinets side by side. The solid state ones are about the size of a single rack or a refrigerator and so efficient over the tubes they will pay for themselves pretty quickly in power consumption. Tech just is evolving so fast. I was watching a video on the Long Lines microwave sites and how huge that equipment was. Now I have a wisp on my towers all over the region and I think they are moving gig speeds through equipment you can lift with one hand and costs a few hundred to a few thousand dollars. Changes so fast and old tech gets pushed aside. Without people like you preserving it and people like both of us learning as much as we can from the few people left that know it and the notes of those before them it would all be lost to the past.
I am working through videos right now. First, you are an excellent person to communicate this information. You care, are clear, and passionate.
That alone makes the whole thing worthwhile.
Art? YES!
It is amazing to me to understand a completed call is an actual closed circuit! Crazy cool.
I hear hints of this exchange being able to talk to the outside world. I hope that happens, or at least to other network bits still being maintained for whatever reasons.
I am sure it has been asked, but I will again anyway, is there any possible value to having some subscribers?
Probably not.
The thing I find most memorable, in addition to the many cool sounds one used to hear, is the audio quality. Sure, bandwidth was not all that great, but the simplicity of the system electrically, along with the often robust materials used, made it accurate!
Hearing people is a compelling experience.
I should not write this, but I once worked with a woman and we both were married, both found each other attractive, but also both unwilling to really act on that knowing better what a mess like that possible is like.
So we had fun.
One day, she put a little perfume in the handset, and when I would take a call, there it was! Hilarious! Then she called and did that ASMR thing, clicking tongue, and thebother sorts of stuff ASMR is well known for today.
The old gear conveyed all that properly and I had a full response! Tingles everywhere, and I have to say nothing modern, except for the high definition calls made possible when all parties on a call have compatible cellular phones, can compete! The ultra aggressive lossy compression eats away at the very soul of a call thus turning it into something functional, but no more than that.
And when I have an opportunity to consider older tech of all kinds, it seems universally true each tech type will have a thing it does with excellence. And we can replace it, sure.
But the cost is that excellence. Doesn't make the replacement unworthy or bad. It isn't. But there is that bit we will invariably miss and the fuel of nostalgia is delivered right to a vein to be appreciated proper.
Maybe I can get a tour one day and place a call and talk to someone. Would live to hear that intimate speech again. Makes one appreciate people, what talking really is and how it can make us feel.
Thank you for donating your time. Maybe one day it can be a job. I think it should.
Keeping older tech alive has merits. We never quite know when mining the work of our past may yield insight of some kind.
All that relay logic in action is music to my ears.
This thrills me to see the #1 XB being taught new tricks!
Interesting stuff. I worked on a UK crossbar exchange. It was a development of a French system. Quite different from that. There was a rival system in the UK which looks a bit more like that. It took a few years to get to grips with crossbar. I remember registers, line units, group units, markers, translators, incident recorder etc. All scrapped many years ago. I don't know if any went to a museum.
Alligator clip jumper wires. What a great way to debug!
How this beast works? Easy answer: FM ... as in freaking magic .... or maybe FR ... as in freaking relays ...
This is so cool - thank you for sharing!
Thank you!!! Good to see you!
"But at least it gives me a job to do." Does the museum make a pretty good amount by admission prices, or just by grants, or...?
This is so cool. I want to learn more about POTS
This is amazing!
excellent video, thanks. the link in description is missing a ")" at the end of it
Thanks, removed the link. Couldn't get TH-cam's link parser to handle it :\
This brings back to mind a question I've had for years. (WHO, or WHAT) is the supervisory power that tells the "Central Office" to add a NEW PREFIX? (The Bell System)? And how many prefixes can you add to the #1 Crossbar? Obviously it has to be a prefix that doesn't already exist within your Area Code... but, HOW is it decided what the new prefix will be? ... 949...885...623?
So neat! I wonder what it was like to work for 'Ma Bell back in the day.
it was amazing.
@Sarah -- where/how did you learn all this? You have a tremendous amount of knowledge of switches and terminology. I'd love to hear how you came by all of it...
Maybe I'll do a video on that someday. One (partial) answer is that these switches needed serious maintenance when I got to the museum. A really effective way to learn a system is to have to repair it. By solving problems, I'm forced to work through the logic of the machine, and deal with whatever comes up. Much better to learn that way, than to explore a fully working system.
Corporate bureaucracy at its finest. Expected nothing less from AT&T. :-)
But really cool that you hook things together like it would have been done in the real world, rather than just essentially making it a basic demonstration.
And I like how simple it is to add a new route to the marker - just a couple of jumper wires and youre done! Fantastic engineering.
This is awesome
Loving these videos and currently working my way through all of them for no particular reason other than being a geek and finding them really interesting!
I was wondering with the compensating resistance values, are there a discrete set values to choose from or was it a case of measuring the actual line characteristics and setting a bespoke value for every trunk?
Thanks! The compensating resistance values come in discrete steps of 300 ohms, so 0, 300, 600, 900, etc. You can find a value that works for any local trunk using those increments.
What kind of stripper/cutter/plier things are those? I'll be wiring a step switch soon and those look like they will save time.
jonard.com/ks21257l3-l3-type-cut-crush-strip-pliers-0
They pop up on eBay a lot too. Best for cloth-insulated cable.
@@ConnectionsMuseum Thank you!
this is impossibly cool. also dont breathe that solder smoke ya silly goose pls live forever
do you think you can make a video showing the sounds on the subscriber line (click, clanks, and tones) and pointing out what parts of the switch are actually making those sounds with the call progression?
That's a good idea. I'll try!
@@ConnectionsMuseum I always wondered that after listening to the recordings on phonetrips.com
Surprised those CCFs are solder terminals and not wirewrapped. Does anyone know when Bell/WE started doing wirewrap and moved away from soldering the CCFs?
Not sure what a CCF is. The first mention of wirewrap is in the 1951-07 Bell Labs Record "Mechanically Wrapped Connections" www.telecomarchive.com/docs/bsp-archive/BLR/29-7.pdf
@@ConnectionsMuseum CCF = Cross Connect Field. Sorry about that (OSP is my world, not the switchroom)
CCF really means, a Cross Connect Frame, eg. MDF, Main Distributing Frame, LDF Line Distributing Frame.
Very well explained. Thanks.
I remember adding new NNX and NPA codes into #5 Markers.
Another great video again Sarah 👍
Does the comment section know if there's a museum in any way similar to this in the UK?
There are working exchanges on display at avoncroft museum, Milton Keynes museum, amberly chalk pits, dean forest railway, and a handful of other places. Hope you get a chance to visit some of them!
This is great video, brings me a lot of good memories working with Ericsson, NEC and Siemens crossbar switches. Did you have any videos on rotation switches?
How many route relays were there in a 1XB?
It was variable depending on needs. We have about 100, i think, but it could go up to several hundred, if you had enough routes to need them.
As many as needed, Office codes start at 222 and can go to 999, you need one for each office code.
Sounds like you're giving it all the information that the "decoder" unit in your most recent video was giving to the sender.
Thats correct. By the way, panel switches have "decoders". Crossbar switches have "markers". They are indeed different, but play a similar role in call completion.
Sarah: do you know of the user Evan Doorbell on here? He has what must be the most exhaustive series on analog phone exchange sounds! If it either made, carried, transferred, or accepted a phone call, it's in one of his uploads.
Just thought I'd share that resource. "Make a note of it" as the late Jane Barbe famously recorded!
This is great! Thank you!
The TK relay is the 100 year old equivalent of an assert statement!
It just goes to show programmers have never trusted other programmers.
I didn't think of that, but its true! Markers are full of things like that. I call them "gating" statements, but that's not really an official word. It's just something that I came up with. They function like an assert, and they establish check-and-stop points to safely exit with an error if something goes wrong. (You wouldn't want a $20,000 marker to hang indefinitely!
Great stuff!
You're hella cute c:
agreed :3
Omg you’re awesome!
How did you learn all of this? Training classes long gone lol. Also how did the #1 differ from the #5? Excellent vide btw!
I learn first by doing, then by reading about what I just did. I am sort of obsessive, and have a very good memory for this kind of stuff. We have the books, and the machines, so I can make the machine do something, and then read the book to figure out why it did that :)
The #1 and #5 both used crossbar switches, but the layout of the machine is very different. It's sort of like asking "whats the difference between a semi truck and a family car?" Both have wheels, but their purpose is very different!
The 1XB is the semi truck of switches. It's huge and powerful but not that great at going around sharp corners. The 5XB is the family car of switches. Not as much raw power as a 1XB, but it can easily get in and out of a tight spot, and its more comfortable to sit in!
Love these videos.. I noticed the museum is a member of c*net.. are those links still operable?
First!!! Love your videos!!
Wow that is a lot of work. It looks like you have only 1 marker, so you probably don't have a route and rate verification test frame.
I'm surprised this stuff still exists let alone someone would be making it work.
Me, towards the end of the video: I should ask if there is something I can read for the basics, because I don’t know things, like tandem
Sarah: ... so this is what tandem switching is...
Wait the museum is open? I can't get anything on CNET to actually work! What gives Sarah?
sean juth I've never been able to connect using cnet
@@bdm1019 I have before. Now it doesn't work
I've been able to dial the panel switch on CNET. PArkway 2-5118 is a good test as it gives you a flashing busy. Although connectivity seems to be unreliable sometimes.
From a billing guy. How well did the billing work :-)
In the early days of Xbar-1 we had to photograph all the zone registers and send the films to accounting, then along came Vidar, a magnetic tape, reel to reel recording system. We had to remove the tapes every morning and send them to accounting.
There weren't many women working on switches like this in the 1970's women were just coming in as techs and didn't have an easy time asthma was an all male dept. He
The lack of simple jargon definitions dilutes the presentation.
Imagine you're not talking to another familiar with the terminology.
A quick slide covering the call setup and control flow would really help get the concepts across when you're then walking through the signal flow at the equipment.
We need a "map" to follow you easier.
Thanks for the feedback. I'll try to do that sometime. For now, this will have to be enough: telephonecollectors.info/index.php/browse/bc-switching-library/western-electric/weco-switching-documents/weco-crossbar/11743-we-1-xbar-completion-of-a-call-bulletin-2-5-1-oct39
and en.wikipedia.org/wiki/Number_One_Crossbar_Switching_System
I can't even begin to understand why any timely, purposeful upgrade would involve insurance. Why would removing stuff like this from service just for an upgrade have anything to do with an insurance claim at all? Secondly, why would insurance demand that a failure be purposefully manmade and not consider that insurance fraud? Geeze, I don't get to purposefully crash my vehicle just so I can claim a total loss, do I?
I heard you say "writing it off the books." But why is that an insurance thing rather than what I'm used to hearing: a tax thing, and then why should they feel like they have "lost more money" just because of if the owner had not destroyed the machines, even though they wouldn't have lost more money? In the auto insurance industry, consumers actually get to sell a vehicle that was already totaled! Reserving the salvage right. The insurance co. doesn't deduct much and I've done it; it's pretty cool that I can actually keep the money minus a little, AND the vehicle! So if they allow this in auto insurance, then what's the problem with something similar here?
12:50 I'm still puzzled and disgusted by this intentional destruction of hardware, instead of just writing it off.
This was required by the IRS to be able to take it off the taxable inventory list. The TELCO'S would not spent the time and money if it was not required.