Last Crossbar Telephone Switch (Central Office) In The 2022 PSTN (TESLA UK11 PBX)
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- čas přidán 23. 12. 2022
- Probably one of the last crossbar telephone switches this size in the public switched telephone network still in operation as of december 2022.
This system is a part of a fairly large installation of private branch automatic exchange (central office) with 800 subscriber lines and 96 trunks. Installed in early 1980s this switch is capable of direct inward dialling, automatic and semiautomatic traffic with 3 operators positions to handle calls.
This switch is finnaly scheduled to be replaced in 2023. I will cover extensively all the parts and call procedures in the next couple of episodes and do my best to save this switch from scraping. I also have the complete documentation which consists of literally thousands of pages and large schematic diagrams. I will share the content as soon as I find the way to do that.. - Věda a technologie
I hope that this is saved. Nice and clean.
Thanks Phil, such a honor to hear from you. Yes, Im buying the switch and renting the place so I dont have to move it (for bow). Im looking to hooking it up to the C-NET, do you think you could help me with any advice how to become a part of CNET? Big up !
i hear that the best way to get connected to the C*NET is to get a dedicated asterisk server ( little desktop pc ) and hook it into the network from the asterisk server
@@suriva what @supercattelephone said. FreePBX is easy to get going. On a small PC. You’ll need FXS interfaces for the trunk lines.
I’m doing something similar but with FXO ports to remote extensions over the internet to remote analogue telephones.
I like the aesthetics of that telephone room. It has a very 80's feel to it!
Those top-down Nixies are super neat!
imagine caller line identification in 1980s....
From back when telephones were used for serving humanity instead of tracking and controlling us.
Excellent video. Can't wait for the next one. I used to work as a switchman during the 70's for southwestern bell in a local, toll, and Cama Step by Step system. Our Cama system used 100pt crossbar switches as incoming dial pulse register links. We had 2 decoders, 4 transverters, 4 recorders with perforated tape units. The switch fabric was 2 stages os SxS switches. But I've always wanted to know about markers, and other common control equipment. Our equipment was all western electric. I love the layout of your tesla system. I would love to know more, even though I'm 71 and retired. Thank you so much.
thanks alot for your interest. we have 800 subscriber lines, 52 incoming DID trunks, 32 outgoing trunks, 8 bidirectional (long distance) trunks. there are 2 central markers, if I remember good 16 originating (local) registers, 8 incoming registers (from trunks) and 7 outgoing registers. as it is just an electromechanical switch it has not so common features as call waiting, intercept, forwarding, chain call, serial lines, trunk to trunk connection... hope I will bring more videos in the near future.
@@suriva thank you. I can't hardly wait to see more. Very interesting.
I worked for GTE in the USA. Have to say that the outer frame panels are SUPERB! We didn't put up all those frame panels on ours and everything was directly accessible without removing anything. That said, the later computerized switching systems had enclosed frames, raised computer room floors, and air conditioning.
Thank you for your interest sir. Those are the little "cultural" diffrences.. basicly we had same switching systems like #1 and 355A step, #1 and #5 crossbar, crossbar and 4A tandems, even clones of all-relay switches like CX100, CX1000, later 1ESS/4ESS based topology like E10, DMS10/100, S12, ESWD in late 90s/early 00s up to softswitches and VoIP which I do not consider interesting anymore..
Wow it's so cool that it's actually still in use. These are before my time but we have a DMS100 in our building and manage many other ones too. They keep talking about decommissioning them but I have a feeling it won't happen in my career. It's cool though how this tech was designed with such a long life span.
thanks for the reply. do you mean SL-100 which is DMS100s PBX version ? DMS100 is fairly large PSTN switch, both definitelly worth saving !
Yeah DMS100, we manage a few 200's too! Fairly large telco. I do hope that if they decom them they don't just scrap it, would be cool to get dibs on some of that hardware. I wouldn't know how to make it work but would be a cool novelty to at least setup the racks and stuff.
czcams.com/video/-8qjfPgVAAs/video.html
you wouldnt be the first one to have dms100 in a garage :)
@@redsquirrelftw you have to do this. If you can find the space you should do it. Live on a farm run it with solar. Haha. There are people out there that can help you get it going.
Amazing; I never would have expected an old electromagnetic exchange could still be in use, even in a private business capacity.
actually its government owned
@@suriva Do all the offices in the government building already have RJ-45 ethernet connections that already go to PoE (Power of Ethernet) switches? If so, a switch to a VOIP based system such as Cisco would be fairly quick and easy.
ahahah, ofc we have VoIP (asterisk) system for years, this is the last analog switch just because it servers remaining analog lines in 5 office buildings... there are hundereds of VoIP phones.
Great find, but this title is misleading for two reasons:
- PABXs are not part of the PSTN, so this isn't a switch that's *on* the PSTN, just reachable from it. Otherwise, this would be completely false as there are hundreds of electromechanical switches owned by hobbyists that are not on the PSTN, but publicly reachable from it.
- There are many electromechanical switches still in use in the former Soviet Union
oh, then Im sorry for the clickbait. actually its a bit more complicated. when it was built the incoming trunks were literraly the last 3 stages of the tandem office. nowadays its on a three-wire channel bank. you gotta ground "c" wire first, wait for "-" on "b" before sending dial pulses on "a". there are 8 incoming (dedicated) registers so it could be connected as a last selector and connector of a tandem step-by-step office... other curiosity is that this switch is governemnt owned and still operational as of today :D
@@suriva so the line is blurred. No pun intended. It’s a PABX that is integrated with the PSTN in a relatively sui generis manner. No apology necessary.
Trunk line signalling is interesting for integration with asterisk.
Thank you so much for doing this. I hope you are able to save the switch and the operator positions.
yes Im doing my best to save it all.. hope I could mange to rent the space so I dont have to remove it.... but its like hell of a dough yk
@@suriva renting the space while you get your plans together is good but obviously not a long term solution. One step at a time. You’ll figure it out.
Amazing that this was still in use, I started in Telecoms in 2003 and learnt about Crossbar (theory not maintenance) and even then it was nearly 10 years since the last crossbar exchange was closed in England! (1994)
isnt it amazing ? its still working btw... yes we got rid of most crossbars in mid to late 90s too
perhaps the Connections Museum in Seattle, Washington, be contacted as they very well may be interested into its collection
Im a big fan of connections museum however I will preserve this switch in fully working condition my self
I can't believe this was installed in the 1980s. Where I live , in that time frame there would have been an SL1 fully digital system instead
wait wait wait... there were few Nortel SL1s in 80s and literally tons of Crossbars and even Steps back then. and yes there was a fully digital UE installed in the same time period (with size of a fridge) but was not EMP proof...
I work on a pstn switch that's been online longer than i have been alive..
Outstanding!!!♥️🔥😀👍
This is so cool, I'm such a fan of old 1980s equipment. Sadly I don't live in the US so I can't ask for salvage rights or I would be straight down their. Sutch as same this is all going to be scrapped.
This isn't in the US. I think it's the Czech Republic.
@@batlin Oh sorry for getting that wrong!
@@GreatGizmo74 no worries, I wasn't too sure until I spotted a sign with "P. Modřany" -- Modřany is a suburb in Prague. Just like you I'd love to be able to save stuff like this since when it's all gone, it's gone for good.
good assumptions guys. actually I wont diclose the location since I want to save it. just to remind you that czechoslovak products were exported all over easter block.
I’m surprised a switch like this was built in the 80’s, I thought mechanical switches and the requirement for human operators for long distance calls were phased out by then.
They were still made at early 80's they were already "computerise" the switching matrix only where still mechanical.
The switch evolution was
mechanic "brain" and mechanic spatial "connexion matrix"
electronic"brain" and mechanic spatial "connexion matrix"
Computer "brain" and mechanic spatial "connexion matrix"
Computer "brain" and analog electronic spatial "connexion matrix"
Computer "brain" and digital "connexion matrix"
The digital connexion matrix was designed in the early 70's since then the voice was digitized and send as packet just the same way it's done with Ethernet packets. but as you can imagine it cost a lot at the time; even if far more reliable (no more degradation in transmission) and huge multiplexing capability. So crossbars was still made even if already outdated they work well., just like you can still find DSL modem as you don't have fiber everywhere !
exactly. there were common program controlled analog switches in late 1960s (#1ESS) while "brute force motor operated mechanical" panel switches form 1930s were still in operation well into 1970s ... step-by-step COs like #1 or 355 invented in early 1900s were in operation into 2000s... EWSD, 1000 S12, DMS10, 100 from 1980s could be still found here and there today.... and human operators were absolutelly common even after 2000s its just matter of last decade that companies dont wnat you to speak with real people.... "if you want an operator to hang up on you press star now"
Trabalhei nas ARF ERICSSON , onde esta este equipamento ?
I think the camera will make me sea sick if I keep watching!
Where is it located?
I see there Czechoslovakian phones.
Is it some fabrics phone switch or village?
Good catch. The CO is made in Czechoslovakia. Sorry I aint giving out the location before Im getting the ownership.
@@suriva Lidém kteří se snažejí zachránit takové ústředny od kovošrotu akorát fandím.
Doufám že se vám podaří vykoupit a také doufám že jednou budu mít možnost se s tím zahrát.
Jak to dopadlo nakonec? Můžu přijít na exkurzi?
well would of been more fun if this would of been narrated by you and not a machine.
next episodes..
This looks like an LM Ericsson PABX. If true, please advise the model number. I worked on many similar Ericsson PABX's in the 1970's
nah, its eastern block "copy", been produced since late 60' to mid. 80'
Where is this? Is it possible to take a tour?
The switch is stil in operation. Im trying to save it. Once its decomissioned I plan to make it accesible (both telephonewise and phisically)
Zdravím, nějaký posun? Odhaduji také že bude někde CZ/SK, protože tam vidím i STP od inomy se mihnout :-) mám taktéž UK11, pokud se povedlo a chtěl by jste s něčím pomoct či ji propojit s IP světem, je možno :-)
dobry den, jsme stale v provozu, postupna migrace na VOIP, ustrednu celou zachovam, snazim sa pronajmou prostory, kdyz ne, odsehuji jinde, muzu mit na Vas nejaky kontakt ?
This video was either filmed after work hours or the employees are not making many phone calls......
Many of the extensions are already migrated to VoIP. There are only 6 incoming trunks left and like 10 outgoing. Was filmed in the evening or on holidays, idk, I usually work late.
Do they still use rotary phones in the organization?
most of the phones are push button but set to dial pulse mode.. worst problem is the voltage 60V.. most of the "western" pohnes could not handle that :D
Any update about this.
Hi Phil. The switch is still in service. If everything goes well Im gonna save it in full working condition. Nothing will get scrapped. Not gonna disclose any details for now but once its decomissioned I plan to make it accessible to public (either telephone-wise but physically too). Thanks for the care.
This is in CZ?
Make sure you save that equipment. Have a chat with the owners. Hire a truck and remove what you can. Its too good to go to waste.
thanks. the owner is the government. its still operational. luckily I work at this place and I will do everything to save it in fully working condition... I wont disclose any further details now that could ruin my plans.
Is this switch for sell?
definitely not, as far as Im alive
Kdepak to je ?
nemam tuseni
Things are quiet.
the switch still in fully working condition. waiting for decomissioning. will try to make it available both telephonewise and physically.