Hah! Yes, by the last day it had really had enough and was properly sulking 😀

I’m having so much fun, and have filmed so much stuff! It’s going to take some wrangling to put it together… but it should happen!

There's possibly not as much overlap as you might think! Peak dialup usage in the UK was in the mid-late 1990s, I didn't know many people with dialup at home until about 1997... but the last strowger exchange in the UK was removed from service in 1995ish So although dialup was around at the same time as strowger, it wasn't really at it's peak until after this technology was fully gone from the UK network.

Thanks! Taking it to EMF is going to be a lot of work, but where else would I take it?!!

It’ll be fiiiiine… 😀

I’ve rebuilt contact sets before, and it’s fiddly but certainly doable! I’d rather replace the whole stack though if I’ve got the right spares. I do keep the broken ones for future repair though! That test probe idea is a good one! I’ll have to add some to my next component order 😀

Sure thing, I’ve got that planned for a future video

Inside dimension (after all the insulation etc) is 3.45m x 2.25m That's just over 11ft x 7ft or "2 and a bit linotypes" I think?

I can’t honestly remember what speed they synced at, but you can probably work that out by looking at what that pair of modems support, and there are probably also clues on screen about what speed they synced at. Terminal emulator on the laptop was just the standard macos terminal, probably running either screen or minicom (I can’t remember!) again you can probably tell from the screen layout. The usb-serial cables at both ends are just generic no-name ones. Most likely prolific chipsets (or prolific clones) Hope that helps

Just rewatched it and paused the video for you. Synced as V.34 at 9600, I used screen to connect to the modem

That’s the modems handshaking to negotiate speed/encoding etc

Yup, those look very similar, although "KS-21257L3" isn't as easy to say as "81s" :D Was there a generally used slang term for them in the US?

did they smell as obnoxious as I imagine they did? The ones I've got are about 50 years old so have probably lost most of their potency!

They were quite nice actually, sort of floral.@@lpbkdotnet

​@@lpbkdotnetlikely closer to forty years, mid 1980s. The barcode implies after 1979 and the phone number implies before 1990.

Hmm… I wonder if any photos of that display survive anywhere. I’ll have to go digging in BT Archives!

@@lpbkdotnet if you find a photo could you let us know , Steve openreach pole tester

@@1961kickboxer I haven't found anything in BT Archives so far (I've been through about 300 photos!) but I haven't given up just yet !

@@lpbkdotnet yes thanks ,it was very unusual to see this display it was definetley at stone or what they called yarn field it was in with all the cable jointing display stuff it just stuck in my mind how adaptable the 81s were .

everything

I think I told the receiving end it could only support 28k (as I was having problems above that, which I’ve since solved) which presumably cut down the handshake time a smidge. But apart from that, there’s no video trickery or anything.

​@@lpbkdotnetit also became shorter thanks to the fact the path between the two modems is very short and it doesn't need to calibrate as much for a good connection

Maybe the internet connection was a bit introverted 😅

That’s what I was thinking.

This one isn’t for sale, but they come up on eBay all the time for £20-£50

When the call finishes, and the people on the call hang up, the indicators associated with the call re-operate and the buzzer sounds (like it did at the beginning of the call) Because the cords are still plugged it, the operator knows it’s a finished call (not a new one) and can unplug the cords.

When the extension station hung up at the end of the call, the dolls eye indicator would raise, alerting the operator.

This is a common battery board, not a magneto board. The phones are ordinary phones, and don't need their own local magneto generators. The equivalent of your supervisory lamps on this board are the dolls-eye indicators. They re-operate when the call clears to indicate to the operator that the cords can be restored. On a true magneto board, the callers would "ring off" when they finish their call, by winding the magneto handle on their phone. That would alert the operator that the call was finished. Hope that makes sense!

@@lpbkdotnet Makes perfect sense. I didn't notice the indicators at first....or rather, I didn't notice that they were not flap type indicators as on a magneto board. Thanks!

2000 type selectors have a failure mode where they can get stuck as it drives round the bank during release, which causes the rotary magnet to burn out. I think the 4000 type was supposed to work around that because the release magnet effectively releases a latch that causes a spring to pull the wipers home? Of course, going back out the way you came doubles the wear on the early choice bank contacts, so 4000 types wore banks out quicker. The other changes in the 4000 were to make all the adjustments screw based rather than "bend a bit of metal" - those were especially unpopular as they had a tendency to shake loose over time. Cue lots of stories about having to carefully sweep the floor under the selectors in the morning and then work out which bits had fallen off which selector etc!

@@lpbkdotnet release magnets can get stuck too, on my switch all of the release magnets are wired with heat coils in series to stop them burning things down if the wipers get hung up in the banks and the release magnet remains energized. I remember the “old timers” telling the stories of sweeping up every morning on the old Strowger mailing list. I also remember a few stories about the smell of burning varnish when the heat coils failed to do their jobs! I’ve heard the bank wear argument too, but was bank wear on the two motion switches a big problem? My pet theory is that the 2000 design was an attempt to be different in as many ways as possible from the American sourced “pre-2000” design as a way of distancing the the British design from the American design.

@@beefchicken bank wear was a serious concern on a busy main exchange, and having talked to people who had to split/repair banks it sounds like a nightmare of a job, even worse than changing a magnet! The 2000 type was already a pretty long way from the pre-2000 (eg being significantly smaller, so you can fit more equipment in the same footprint) so why they went back towards the pre-2000 design by adding a release magnet back in for the 4000 type I don't really know. I have heard it claimed that going back out the bank the way you came is quicker to release, but I can only see how you'd make the argument for 50% of the outlets. They must have had their reasons for the redesign though, but the chances of ever really tracking them down is pretty small! The really nuts one is that ATE developed a motor driven 2-motion selector, electrically compatible as a drop-in replacement, but capable of running at more than twice the speed... but by that point electronic exchanges were already taking hold so t never went anywhere.