DMS-10: The first phone call!

Colin and Matt talk about wiring up the subscriber side of the DMS-10, and we get to make the first phone call on the switch since it arrived at the museum in Fall 2023

[@DeviantOllam]

So exciting that this is helping to route and place calls now! 😗☎️

[@squelchtone]

a wild Deviant appears!

[@DeviantOllam]

@@squelchtone 👏😁 yo, bother, good to see you!

[@DJSubAir]

I still plan to visit soon! Excited to see this working and everything else!

[@joker1859]

Never knew you were a vintage telephony fan Deviant

[@DeviantOllam]

@@joker1859 I am both a fan of the hardware and also a fan of the people there... some of the very best folk in all the land 💚☎️

[@n1gak]

10:43 -- No, no, no ... "We have been trying to reach you about your DMS_10 Extended Warranty"

[@redsquirrelftw]

It's kinda neat to see this in a museum, when we still manage a whole bunch of these at work haha.

[@kencarlile1212]

Typing when someone is watching is always a recipe for me to make all kinds of typos and forget all commands. I can't imagine how much worse I would be on camera... :D This is so awesome, I'm loving seeing this whole process, thank you!

[@lohphat]

Keeping this older tech alive to preserve how we got to today's tech is important. The lesson here is seeing the migration from circuit switched calls to packet switched calls simplifies and reduces cabling and complexity. Broadcast tech is going through this NOW migrating from baseband SDI cabling to the ST 2110 standard of video over IP networking. The reduction of complexity, lower costs, and expansion of new features due to the flexibility IP offers, is following the lessons telephony taught us.

[@KeritechElectronics]

Yes, that's right. As someone who worked for a IP PBX / call center software company, I totally agree. It has lots of advantages. Not being tied to any physical layer, better monitoring available to users, and having advanced functionality like call re-routing, queues, conference calls, whatnot that would have been prohibitively expensive or downright impossible if someone tried that with PSTN...

[@ctillnc]

Hang on. A lot of those features did, in fact, exist in the PSTN. The reality of the times is that they were selectively marketed because they were not as flexible as people wanted. The irony is that many of the early soft switches simply went to the LSSGR and checked off which items to implement at which points in their development cycles. Meanwhile Nortel and many of the other PSTN switch providers turned their switches into VoIP call servers. One can debate the commercial success of those initiatives, but the PSTN had an enormous feature base that the softswitches could leverage.

[@lohphat]

@@ctillnc Yes, but it took the newer switches to enable those features. (See: Vertical Service Codes wiki) I remember when they landed in our LATA in SoCal via GTE in the 70s. They seemed like magic at the time.

[@ctillnc]

@@lohphat VSCs were the tip of the iceberg, in terms of what the 5E and DMS-100 implemented. The good stuff was in features for large organizations (governments, F100, etc) and proprietary non-POTS sets.

[@TechHowden]

Could you make a video about billing equipment, I haven’t found any good explanation of how it worked and how it interconnected with the switches.

[@ConnectionsMuseum]

That is definitely something I’d like to do. It’s a really complex topic so I have to think about the best way to present it. -Sarah

[@ctillnc]

First Call is always a happy milestone. Congratulations! Many Nortel retirees are delighted by your progress.

[@outthereassociates7155]

"Car's extended warranty", Good one. Thank all of you for your hard work so this history will not be lost.❤

[@Starlite123]

That's amazing u guys. Next you need a RC28D and Nortel OM3500. Wire up a T1 so you can connect to another telephone office :)

[@IndaloMan]

Happy memories of the mid 80s when I was in the middle of a UK telecoms 'tech war' in the City of London. Mercury had installed a DMS-100 to offer Centrex services to financial institutions but BT didn't have Centrex available on their 5ESS-PRX. We installed a Bell standard 5ESS in Baynard House and connected it to the network via T1-E1 converters. Side note: I vividly remember the Space Shuttle disaster in January 86 as the news brokr during our weekly progress meeting.

[@brians8664]

My group is slated to decommission a dms-10 next month. We just decommissioned 2x dms-100’s a couple months ago. It seems we are constantly consolidating equipment and replacing most dms-10’s with IP switches.

[@thecooldude9999]

As someone who has built a working step switch, I really hope I can save a small DMS-10 before they’re all gone. Hopefully someday.

[@myself248]

Don't suppose they'd be open to a rescue attempt? Where are they located?

Congratulations! Having worked on DMS-100 provisioning, I know the amount of work to get there!

[@onesixfive]

I worked for AT&T (then Ameritech) in the early 00s. I worked in central offices across the city of chicago, we only had one CO that I remember which had a DMS, when I saw the brown paint scheme it truly brought me back 25 years. Thsts amazing you guys got a hold of one and put it together.

[@Digital-Dan]

As Bob Lucky famously said, and you have conclusively demonstrated, "Alexander Graham Bell not only invented the telephone, but he used up the only good demo in the business."

[@rycat5ESS]

I was at a trailer park last week that had a courtesy phone served by a DMS-10, it had a rather funny sounding off-hook tone, and all the recordings were pat fleet. It was nice to hear something different than a 5ESS :)

[@BlueSkyScholar]

Awesome! I am also celebrating, I put calls through my USI-30 step PBX for the first time this evening.

[@myself248]

I wrapped a couple thousand 89F1F and probably a couple dozen 89E1E blocks in my career, what a blast to see 'em here! (blueorangegreenbrownslate whiteredblackyellowviolet... in my sleep.)

[@activelow9297]

What a sexy looking telephone switch, love that orange and brown.

[@KeritechElectronics]

Nice to see new faces, new gear and those lovely funky phones! :)

[@carpetbomberz]

DMS10 ftw 👍you gotta catch 'em all. ALL the switches that 'iz.

[@der.Schtefan]

Ah, the DMS always reminds me of my young years. Home town in Austria. Young engineer, engineering school visiting the local phone exchange. Them having that "Canadian digital system". Ahhh.

[@robbruno8246]

Congrats on your first DMS10 call, awesome work people!

[@common_c3nts]

Setup a DSL line to get 3mbps high speed internet. What a time to be alive.

[@423tech]

Awesome! Great work! Always love seeing what ya'll are up to.

[@squelchtone]

Proud of you for all the hard work you do on that system!

[@billsimpson604]

Amazing that they could make that work all around the planet. Imagine how many miles of wire that took, not to mention the millions of switches & other stuff. I wonder how many batteries they had just in North America? I'm running on generator power right now, after a tornado took out a good chunk of the grid in Slidell. Great job.

[@jonimiller1954]

How cool, a great job. Lots of work by a dedicated team. Joni.

[@Richardincancale]

One of my friends was a developer at Northern Telecom on this. He told me it was the first switch to be programmed in a high level object oriented language. The first successful call set-up took 45 minutes to complete! It got better though…!!!

[@andyknott8148]

Amazing that an MDF is still the same in Seattle as it is in the UK.

[@RaceBanner_]

1:45 True story: If you pull on your home phone line long enough, it will eventually unravel that bundle of wires.

[@LeeNelson71]

That looks like a Nortel original anti-static wrist strap. Did it come with the switch? I’ve seen lots of those hanging from DMS10s

[@bboogaar]

Great work guys! I’m familiar with Nortel DMS100 and the SL100 (a DMS100 with hotel/motel features). But never saw a DMS10 until my visit a couple of weekends ago.

[@ShainAndrews]

2:28 You did not just run your cable THROUGH my cable rack.... You're in trouble now. LOL

[@myself248]

At least they didn't choke a ground!

[@johnbledsoe8868]

Awesome! Will this be on C-Net soon?

[@Antney-u6j]

OMG! The big orange cork board phone book holding telephone at 7:00 brings back a lot of memories! We used to have one of those and my egg donor (“Mom” is a term of endearment she didn’t earn) would stretch the heck right out of the handset cord- walking 30 to 35 feet away with it, into the living room. I would have to untangle and straighten up the cord every night just because the mess she would leave it in would make me feel uneasy.

[@AaronOfMpls]

On our old kitchen phone (when I was a kid), we put a swivel coupling on the handset end of the cord, to _prevent_ that kind of tangle after stretching it across the house to the couch. It worked well enough until we got a cordless phone instead. That said, we had it on a comparatively-boring early 90s answering machine phone, which itself replaced a '70s-era Trimline. The old Trimline later got plugged into a splitter behind the cordless phone, and placed on a nearby countertop, so we'd still have a handset near the base whenever _both_ the cordless handsets were across the house somewhere. 🙂 (The cordless had a remote charger too for the second handset, with just a power cable going to it.) I'd forgotten such groovy-looking corkboard phones even existed! And how utterly-appropriate for a late-'70s switch, even if much of the hardware has been upgraded through the 2000s. 😎

[@victorcarreras2499]

I worked for PR telephone company for 32 years as a pbx repair technician

[@RichardNickels-ot6iq]

Pretty Amazing Great job 😁💯

[@stupossibleify]

Fascinating video. Could you do a video which describes the circuit or schematic of the analogue concentrators? Puzzled as to how thee system concentrates/multiplexes 2000 lines into a coherent digital signal

[@telocho]

I worked on the competitor system EWSD and internally there are E1’s between the dlu (subscriber line frame) and the ltg ( trunk group) and the ltg are connected to the switching network, which is a space-time switching network (all is tdm, not packet switched). An E1 is 31 voice channels, the dlu has a concentration (overbooking) of 8:1 so for 1000 subscriber lines you would need 1000/8=125, 125/31= 4 E1 lines. Each ltg can handle 8 E1’s and a fully equipped exchange can have if I remember 512 ltg’s. But not all E1’s go subscriber dlu’s, you need half the ltg’s to connect to outgoing/incoming trunks too.

[@itsonlybrad2278]

Congrats to everyone who worked so hard to make this a reality

[@musiqtee]

I started to type out a long and winding comment, but it gets entangled like the wiring looms… I just love you guys for what you are, and what you do. That’s it… It’s all about connections…!

[@KJ7BZC]

Love it, can't wait to eventually see the complex stuff these switches can do!

[@bichela]

Next is to connect to the other museam switches. Panel to thid eould bea blast as well as steo by step call routing

[@w0ffe]

One nice thing to do is to recreate the "Hello Mike; Hello Joe" exchange from Erlang: The Movie.

[@movax20h]

Nice. Good job.

[@poofygoof]

This is leading up to a giant heterogenous multi-exchange call, and I am here for it!

[@EvanVanderStoep]

Awesome job everyone! It’s just great to see this all come together

[@n8wrl]

Love these videos - well done! Need to get out to see you guys. Nice Aggie hat!

[@JayEmbee]

SO STOKED! Excellent job to all!

[@RichardNickels-ot6iq]

Awesome 💯😎

[@rthdavid]

What an achievement! Congratulations.

[@PaulLoveless-Cincinnati]

This is SUCH a good series.

[@johncloar1692]

Thanks another great video. It all way interesting what goes on behind the seen.

[@chriholt]

So awesome!

[@shawnl6959]

Still have a DMS10 in service (well, the line bays anyway)

[@jonathanborchert3633]

Good job! There is a lot to it!

[@shaunbeckman434]

I almost do that same in my job... just for a newer piece of equipment.... near same interface.

[@thesleepingmage543]

Congrats!

[@edwinsinclair9853]

Congratulations great work.

[@JoeHamelin]

Excellent!

[@sletler]

Congrats!!!

[@AlistairGale]

Back in my day DMS-10s didn’t use LCMs, Did they even use software overlays loaded from scotch QIC cartridges?

[@Ranger_Kevin]

congratulations!

[@ncstewart66]

DMS10 intraoffice calls always had an interesting high-pitched "squeak" when the call would complete. Are you hearing this also on your calls?

[@johnpitcavage99]

That was the switch testing for trans hybrid loss so it could set the gain based on whether you had a loaded line or not. This prevents singing on the line.( I designed the hardware.) This test was supposed to happen while you were picking up the handset. Not the case with handsfree headsets. Also you could set this as a one time occurrence and the switch would remember the settings for future calls. You can also set it manually and totally disable the function. Most central office folks don't want to know anything about the loops that the subscribers are using.

[@ncstewart66]

Very interesting! All the calls I ever made on a DMS10 did it. Guess it wasn't on DMS100 as I never noticed it in my DMS100 home calls (on those I only noticed the faint click after dialing an interoffice call). Cincinnati Bell's first DMS10 was the replacement of a Stromberg XY in Union, KY in 1985.

[@johnpitcavage99]

@@ncstewart66 Yea, they could set it once after they determined whether the line was loaded or had bridge taps on it. Then the tones wouldn't be there. Most telco didn't bother. The test was supposed to happen while you were picking up the handset. The hybrid circuit was used to take the 2 wire phone loop to a 4 wire circuit which the switch uses for transmit and receive. Balance is important to properly match the loop impedances and prevent singing and loss. DMS100 never had this feature.

[@212MPH]

Post up a couple of TRAVERs so we can see your translation design ? Are you using universal translations or simple NCOS pre translators ? table IBNXLA etcetera.

[@colinslater195]

I think those are DMS-100 tools. Right now we're just reusing the translations that the original telco had, while we try to figure out what they all mean.

[@212MPH]

@@colinslater195 DMS10 has the same tools. IF you can run a TRAVER that will show you everything you need to know about your translators. The exact call path and ever table the call path takes.

[@colinslater195]

@@212MPH Found it, the DMS-10 mnemonic is TRVR. Looks really handy. This is one of the calls we did in the video. Not too complicated, but we'll see how it looks when we start setting up translations to the other museum switches. LINE BASE LCE 01 1 00 05 6X17 DN 890 0005 OPT 1FR EMR 0 DGT NRML RTP 0 CND TEST ACTV PRFX 1 ASTR N OCTO N DIG 8 TMS 1 N OCTO N DIG 9 PRFX 0 ORIG ACTV PRFX 0 TP 950 N DIG 8 DIG 9 ADDR HNPA TEST ACTV ADDR 903 8900 THGP 890 0 SCRN 0 ORIG ACTV SCRN 0 T800 N TOL N TP ANY N OWT N GEFG DIG 0 DIG 0 DIG 1 TN CURRENT DEST: 8900001 LINE BASE LCE 01 1 00 01 6X17 DN 890 0001 OPT 1FR CWT EMR 0 DGT NRML RTP 0 CND CWID * CALL COMPLETE/DISCONNECTED

[@joeblow8593]

Nice work

[@stephenwells5852]

This video makes me miss my Nortel Option 81 PBX.

[@Skiller71Studios]

This thing is badass

[@rickmarkey6289]

Just curious why you didn't use 66 blocks that were connectorized? You could have plugged the 25pr cables into blocks and cross connected between blocks. AMP made a tool to install 25pr male or female connectors onto a 25pr cable and it saves a lot of work.

[@colinslater195]

We already had these wire wrap versa blocks on hand, and sometimes I'd rather just do the manual work than spend more time tracking down parts. We don't have the big 50 pin butterfly tool.

[@antronargaiv3283]

Don't have the tool, but I predict you will soon get an offer of a donation! Well done!

[@electronicsabuse]

Do you need any 50-pair Krone blocks? I pulled a bunch of them out of a broadcast radio studio facility that was being decommissioned, and I'm looking for a good home for some of them.

[@adamtheshoe]

Did you have a hard time getting the cross-connects to punch properly on your MPC blocks? I was working on some old 70’s-era NT “66” blocks, that weren’t actually 66 blocks, but actually used the MPC-style clips. Modern 66 tools almost work, but not quite. If you’re getting a lot of punches that don’t actually cut the insulation, look for a QTH38B tool. (I’m assuming those are MPC-type clips, I can’t quite tell from the video).

[@colinslater195]

We use wire wrap versablocks, and they've worked out really well. We really only have the horizontal side of the MDF in the cabinet, and then we wire phones directly to the front of those blocks instead of jumpering to another connector block on a vertical side.

[@kpdvw]

is there such a Telephonemuseum in Salt Lake City? I need a part time job there

[@KC-rd3gw]

Could you recommend some books to read on the no.1 and no.5 crossbar? I want to learn more about how they work in detail

[@ConnectionsMuseum]

You can visit my site at witch.spmh.us/library/ Ignore any SSL certificate warnings. I haven't updated the cert in ages. Maybe I will get around to it tonight :) -Sarah

[@Madness832]

At about 3:00, that looks like an Australian red payphone, in the background. If it's hooked up, can you show a call into it?🤔

[@onmyworkbench7000]

He should answered one of two ways 1: *_The number you reached is not in service please check that you dialed the correct number and hang up and try your call again._* 2: *_I am sorry you have the wrong number._*

[@straightpipediesel]

3: Make a fake reorder tone

[@maxdutiel]

7:02 is that m2009 hooked up to anything?

[@michaeljavert4635]

I wish they'd go back to the mechanical ones. Keep the newfangled as a backup, but bring back the mechanical switches, gears, whatever it is called. At one time, (1980's) the phone operator would know when someone's phone was off hook, and would know where calls originated and landed, even if she was not involved in the call. Also the OPERATOR would give telephone numbers and help people place calls. There wasn't information at 1411. If you needed to ring someone, and didn't know the numbers, the operator would connect you, or provide you with the numbers if the person was listed and or published. Also, there should have never been a charge for unpublished, unlisted numbers. We need to go back to a lot of the old ways. Things were just better then.

[@devtrash]

no. no they were not better.

[@michaeljavert4635]

@@devtrash In my experience, they were. I NEVER had a phone problem until this newfangled nonsense came along.

[@TheSonicfrog]

The amount of wire cabling here is simply beyond comprehension, and this is only one switch!

[@victorcarreras2499]

That's Nortel equipment?

[@k7iq]

Is this system on the middle (2nd) floor ?

[@jackaustin3576]

Sorry....I worked step, Number 5XBar and Electronic toll....Long time ago....

[@MariusStrom]

Gig 'em @5:00

[@Pants4096]

Type. More. Slowly. ಠ_ಠ