Great to see the 1AESS / 2BESS / 3ESS commands again. This machine was not designed to be powered down and then back on. Back in the 1970s, when a 1ESS was put into service, the Engineering goal was for the switch not to be Out Of Service for more than 2 hours in 30 years.

Sarah and Astrid, you both have an almost superhuman capacity for patience, good humour and calmness, even when faced with what are clearly frustrating and complicated technical issues with these beloved and amazing beasts of historical systems. I greatly appreciate both of you for achieving something infinitely rare in combining your tenacity with being genuinely awesome human beings. Many others in network engineering would do well to follow your example.

I built the 3ESS systems in the late 70’s from the Northern Illinois Works in Lisle Illinois. Great memories. I also built the 3B processor that was used in the 5ESS till I left Western Electric in 1983.

I was a Test Engineer for GTE back in the 70's and worked on the 2EAX, installing and configuring it at various locations around the country. Great times!

I hear "tapes" and think: someone should make an emulator for that. Three minutes later, you show the emulator. That's fast hardware development! :D

Its amazing just how reliable these old machines were compared to the telephone equipment of today.

I remember interviewing with Bell Labs in Napierville, Illinois in 1981 (no, they didn't hire me). While I was there, they showed me a 3ESS and I heard the horrible noise it made when everything was being reset - all the relays were switching. The person with me commented that if you ever hear that sound in a central office that it meant they were having serious trouble because they rarely reset an ESS.

Coolest thing I’ve seen all week. Wonderful to learn from an engineer who is not just an operator but understands the system all the way down.

This is so cool. I work on old heating controls and I love seeing operators who know the "quirks" and "personalities" of their equipment lol. Yall are legends!

Ahh yess..."intermittent conditions". When I started my telecommunications career on a main distributing frame, miles and miles of copper wiring gave me a "few" of those...daily, lol. Great channel!

Was going to say, the ones I've worked on are literally never fully powered down until they're decomissioned. Different function, but on an HLR (Home Location Register) I worked on, the one time we had to power down a whole frame (because we'd lost commercial power, diesel generator had failed to start and the battery plant was running at 36VDC), when it came back online it had lost 4 of 8 SCSI drives and needed me to fly out and nurse it back to health. Fun times...

Very cool, I worked at Bell Labs in the 80's and 90's in NJ, where I wrote a terminal interface (no API's back then) for the 1ESS, 2ESS, 3ESS, 5ESS, and DMS100. My interface created a single user interface to repair centers so they did not need to learn all the different switch commands of each switch type. This was very popular during the time when they had to verify the PIC code, during the growth of new long distance carriers, like MCI and World Comm. The thing about the 3ESS was it was a very small and remote located switch and the only access was via a 300 baud modem. How times have changed.

Holy sh!+ that is nuts. I'm a 48 year old vintage (80's) video game and computer collector. I have never seen any thing like this! Thank you!

How was I born in Puyallup and yet had NO CLUE the connections museum was a thing?!?! I could nerd out in there ALL DAY!!!! I'd be able to listen to you explain this stuff all day.

I'm so happy to see another video from the Connections Museum! Feels like we were waiting forever; it was worth it. :) I've never touched a 3ESS before, but I managed an Avaya Communication Manager PBX for years. The shared "heritage" between CM and 3ESS amuses the hell out of me. :D When I started watching videos on 5ESS and 3ESS, I was astounded by how much seemed familiar.

As someone who works in modern telecoms and sees this equipment retired in place all the time, its really cool to see it in action.

Finally! I have been waiting for this for years! I can't wait for the 3ESS to be back into full museum service! Thank you all for all of the hard work!

When I went to network switching systems operation school in 2002 I was introduced into the world that you are showcasing. Thank you so much! I've been a phreakophile my whole life.

This stuff is fascinating. It's older, but not that different to powering up a late 90s aircraft. The act of powering it up can generate faults that need to be reset once everything is stable. It's quicker than this, though haha

Wow, that's quite a process and a quite a priviledge being able to do this!

PUC data links were my bain back in the day! 45 years in Telecom and I am amazed that these curators took this tech ( and read the BSP's) and have it working again... Congrats and Thank you!

Whoooooooa, I've been missing you for so long :) Love the 3ESS tape emulators - modern electronics coupled with antiquated systems are really my thing... this said by someone who built a few Raspberry Pi based controllers for a Monotype composition caster.

When I worked for Nortel installing and testing the DMS I would sometimes see these in the office. I miss working in central offices. It was a good company to work for.

Oh, this is absolutely beautiful to see!! Funny to think, this process was intended to be done only a few times ever at most, if even that, and it has to be done each time the switch is to be brought into action. Tedious in a way, but certainly magical to do -- to boot such a computer in such a hands on way, all for it to handle phone calls. I have to be that guy -- when might we maybe be able to make a call into or through this beauty, or will that likely forever remain a :"need to visit" kind of thing?

Need to put together a check list like an aircraft pilot uses then publish it here for the rest of us to follow. Thanks for the video.

My dad worked for AT&T from the 60's through the 90's. We had a local mom and pop telephone provider in Califon, NJ who had advertised to come see our new switch gear one time . Once he saw it he knew it was an old 3ESS system they had dumped.

Thanks so much for doing this! It is interesting that these were designed when the control console was a teletype terminal and that the machine can't talk any faster than 110 baud.

Although I haven't seen a cartoon page or an RCV menu since about 2006, now I know where all those funky RCV commands I used on the HLR came from (at least I didn't have to wait for everything at 110 baud though!). Surprisingly I remembered all the status returns ("NG"=="No good"; "IP"=="In progress", etc.)

Hi, I'm currently underway with network engineering studies. While I'm engaged with enterprise level state of the art systems, I also know the value of understanding our networking heritage and where these modern systems came from. That being said, I appreciate these videos even moreso and intend to utilize aspects of these systems in my studies as well. It's just so different when you're passionate about the subject. If I try and talk about things with others, their eyes start to glaze over after a few minutes. It's so beyond refreshing listening to my people discuss these systems. Just top down, I love troubleshooting. I love having to drill down into issues where you don't have proper schematics available and not just memorizing button press sequences but knowing WHY those buttons are pressed and what they do.

Its amazing you have all those steps memorized. Wow.

Ammazing. I really like this kind of installation, driven by simple mini-computers. Lots of electromechanics driven by a small, limited, slow brain. It is very interesting to understand how things were designed with such (very) limited computer ressource. Thank you for sharing all that.

I’m sick in bed today and this was a great distraction! Thanks!

This is incredible. Huge props to y’all!

Sensacional, sou fascinado por centrais telefônicas antigas!!!! Brasil!

Wow, cool to see this again, I used to install mainly the 5ESS and did a lot of tearouts of 3ESS and others along with crossbar and power.

This is mind blowing attention to detail !

I’m 20 and kinda insecure about being gay I’m ngl but seeing a person like you do what they like in life and being yourself gives me a great amount of hope for the future 😌

so. freaking. cool!! I doff my cap to Astrid and Colin for work getting this piece of history working again.

This is so insanely nerdy in the best way possible. Love it! :D

Thank you for all the shares - I’d love to visit, omg!!!

I love this walkthrough.

yaaaasssssss Ive been waiting so long to see this video! thanks for making it!

Remembering all the commands and how everything works is a real skill set very few people have I wish my brain was better I can't remember things like this I try to learn new things but I just can't get it to stick in my brain Same thing with another language. I couldn't get it to stick either It is good there are people like you in the world

What a romp down Nostalgia Lane. Thank you.

I used to commission Philips EBX8000 PBX’s all over the world. Although these were a little less complex, not much so: they could have up to 8,000 extensions. Dual processor reed relay switch under stored program control, loaded with paper tape. Operated in hex with 16+ switches. Remarkable how common many of these concepts and procedures are! And it used to take me an hour to boot up an EBX8000: these too were designed to stay on.

Love this channel and this comment section! It all fills me w hope tbh

I'd really enjoy more videos about the 3ESS :D

No clue what is going on here but seeing two wonderful geeky women like me working and nerding out is awesome

I guess this is how non tech people see IT people. I don't even know what I don't even know. But all of this is seriously impressive, how everything is analog as hell but still digital. And it looks like something out of a cold war bunker.

I work on cutovers from 1XB & 5XB to 1AESS in 1982 and later on with 1AESS to NorTel DMS-100

this was amazing!!! congrats!!

Wow, I'd love to learn more about this system! The command format is intriguing.

Boy does that bring back memories I worked for Verizon for 35 years and spent a lot of time on a number 3 ESS switching system

Very cool. Hope I can visit some day

I spent a lot of years working in Telephone central offices. The sound of those power converters and the smell of the RH power cables are very familiar to me. That and the incessant relay clicks.

Back in the late 80s I replaced one these with a DMS100 remote in a small community outside of Witchita KS. I dont remember it looking like that. I had to hook up the Nortel Board to Board tester no a no test trunk on the #3. Took me forever as none of the local techs seemed to know much about them. Finally got it to work and that was the last I ever saw of those machines

I love when massive ancient computers are hooked up to small modern computers running minicom or something because genuine teletypes are a pain to obtain lol

I think the university here still uses the 5ess.. as an analog backbone.. still used for some feeds and the national weather service and emergency still uses it for clock and broadcasting relay... crazy huge mainframe with 5 levels of entrance cables feeding the campus.. most are cut or repurposed but still have the glass batteries and switchgear running 24/7.. gotta use that old software to set up..

Fascinating!

That is just amazing.

Super cool !!

Wow! Reminds me of the days back when I worked for MobileComm, a Bell South Company, rebuilding voicemail machines. The VRS in particular was great when it worked, and pure hell when it didn't.

Do you know how much of the difficulty is normal? How much is due to flaky hardware you haven't figured out yet?

It's ALIVE!!

".... and then it will usually come up cleanly" is a simple phrase encompassing much potential pain.

Did you mention that the two boxes that take 10 minutes to boot (with the marching lights) are trying to 'come into phase' with one another or another system.?

Extremely interesting

Neat stuff, thanks for your hard work. What switching equipment did Ma Bell use on its teletype network?

12:54 - "...taking a circuit diagram off the edge of the page" Here be dragons.

While I'm more into 1A2 collecting myself, I find these videos fascinating. After all, a 1A2 system would be dead without something like this behind it! Thanks to you for maintaining this wonderful piece of gear,cans sharing it with us! Is this somewhere where it can be seen in person?

How the HELL does one even begin to learn all this?? I bet the two people who work on this are the only 2 out of approximately 7 BILLION people on Earth who could get this up and running...that's pretty amazing if you ask me.

WOW AMAZING TECHNOLOGY FOR TELEPHONY

That's really cool, I imagine this is similar era as DMS10? We still have lot of DMS10's in operation, this kinda reminds me of them. I've never had to INI one myself, I'm just a NOC tech so we don't dive too deep.

Does this switch have coin control for pay phones? That would be cool to see pay phones connected here and have coin return and coin collect work properly.

I hope this process they're describing wouldn't involve fooling with live electricity. As I am sight challenged, I'm really fascinated by machines that have to do with telephones. I hope that one day I can come to this museum.

Is there a resource or manual describing the terminal interface for the #1 and #3 ESS digitized somewhere? I'm really curious and would love to learn it.

What is the oldest computer you have? Also, do solar flares affect some of the older units?

Here in Toronto near the Eaton center bell had a building right beside it and tucked away in the basement behind a glass wall was a fully functioning switch that was for the building and likely the downtown core. I managed to grab a few pictures for a project I was doing at the time. A couple of years later they frosted the bottom five feet of the glass wall. It made me sad to know what was in there and that it would never be visible again. A few years later they dismantled it. and the room's lights were turned off and then the whole section of wall was replaced with Gyprock. I would love to learn more about that if anyone has information.

What is the relay that you hear clicking on the background the whole time?

What's the relay cadence I'm hearing that starts at 6:24 when booted? I recall hearing that exact same cadence when placing a call between the rings - mid 80s - Detroit area.

Curious to know what parts are pure digital, pure analog, hybrid

Interesting . At the end of boot , will show Arnim Zola ? (I already have trisuit from Switzerland)😐

So awesome to see this stuff running, it would be neat to have an actual teletype connected to that serial port too. Did the 3ESS have support for remote management over a modem?

I'd like to see the boards in the 3A CCs themselves. I understand the 3ESS is a very rare machine, built for small offices and not produced in particularly large numbers.

Wow. She’s like a walking encyclopedia!

I was a test engineer at OKC Works where I ttouble shot manufacturing defects on #2 ESS processor and AIS system. Used to design machine code programs and hand mag twister memory cards as trouble shooting aids. Lotsa fun. Would like to see a 2ESS processor video because I would have likely tested it back in early 70s.

Because this is a *3*ESS, and not the later 4 or 5, those processors are custom logic, not the 3B20D that would drive the later switches, right?

this was really interesting, is there any further reading on the 3ESS available online? particularly on its processor?

does this have 2 3A CCs for redundancy? kinda looks like a pdp 11 lol

Fascinating video. Looking at the console, 110 baud is painfully slow.

This is the system that replaced the step by step 355a office that I took care of in 1978 for southwestern bell. This was quite a change. Thank you so much for this interesting video, brings back alot of memories. If I ever get to Seattle, can I see this system?

I worked on 1A for years. I think a few 3ESS guys came over to 1A.

Thanks for another interesting video, girls. Always fascinating, always a pleasure to watch.

Will you be making a D4 Video?

So is the computer you're using for a teletype more powerful in terms of processing than the whole switching machine itself?

I recognize most of these components, but I don't see one of them - - The sledge hammer!!

Blows my mind that all of this equipment taking up half a room can be replaced now with PC that can handle 100x the amount of calls!

cant wait to move closer just so my girlfriend can volunteer here. she real enjoined her visit.

it's nice to see astrid again

Are you running the tape emulators for convenience or because you dont have the real tape drives?