I connected self powered crank telephones to my home phone wiring for use as intercoms. Crank one and the others ring. Pick up to engage the battery powered talk circuit and you're chatting with Mabel like it's 1915. I did replace the old dry cell batteries with lithium camera cells so I don't need to think about them for a decade.

We have an Ethernet run that's not in use right now. I had a Cisco ATA from earlier experiments so I picked up 2 old phones with proper bell ringers and now the kids can call up from the living room to my office when it's time for dinner, they love it.

If it was Nintendo instead of Sega, everyone would be slapped with a cease-and-desist backed up with the threat of lawsuits.

The second I heard that engine fire it was 1986 in my brain again. I could smell the fuel and feel the finger damage from repeatedly trying to get the darned thing to start. Followed by damage on the other side of the finger when it actually did. Ouch.

Flick a pen on it instead.

Ah, the classic "chicken stick" approach. No shame in that!

Me too, brother.

Cox 0.049?

This is an extremely salient point:

...some mockingly asking whether the firm would've maintained the same tenacity and reimbursed the Intern had he been fined 50,000 RMB at the event instead

It seemed like the future was all cloud but this year's exhibit hall was packed with infrastructure suppliers. Every third booth seemed to feature valves, pumps, massive high density power distribution systems and all the stuff you would need to cram a megawatt of electrical power into the smallest space possible and then extract the heat. Most notable to me is the waterless phase-change heat extraction provided by https://zutacore.com/. Their technology avoids massive water consumption and provides a high temperature heat source that is immediately useful for campus heating or co-generation.

It was like that last year too.

Visiting Bletchley Park and seeing step-by-step telephone switching equipment repurposed for computing re-enforced my appreciation for the brilliance of the telecommunication systems we created in the past 150 years. Packet switching was inevitable and IP everything makes sense in today's world, but something was lost in that transition too. I am glad to see that enthusiasts with the will and means are working to preserve some of that history. -Posted from SC2025-

I wanted to learn more about computer hardware in college so I took a class called "Cybernetics" (taught by D. Huffman). I thought we were going to focus on modern stuff, but instead, it was a tour of information theory- which included various mathematical routing concepts (kissing spheres/spherical code, Karnaugh maps). At the time I thought it was boring, but a couple decades later, when working on Clos topologies, it came in handy.

Other interesting notes: the invention of telegraphy and improvements to the underlying electrical systems really helped me understand communications in the 1800s better. And reading/watching Cuckoo's Egg (with the german relay-based telephones) made me appreciate modern digital transistor-based systems.

Even today, when I work on electrical projects in my garage, I am absolutely blown away with how much people could do with limited understanding and technology 100+ years ago compared to what I'm able to cobble together. I know Newton said he saw farther by standing on the shoulders of giants, but some days I feel like I'm standing on a giant, looking backwards and thinking "I am not worthy".

When the Bell System broke up, the old guys wrote a 3-volume technical history of the Bell System.[1] So all that is well documented.

The history of automatic telephony in the Bell System is roughly:

- Step by step switches. 1920s Very reliable in terms of failure, but about 1% misdirected or failed calls. Totally distributed. You could remove any switch, and all it would do is reduce the capacity of the system slightly. Too much hardware per line.

- Panel. 1930s. Scaled better, to large-city central offices. Less hardware per line. Beginnings of common control. Too complex mechanically. Lots of driveshafts, motors, and clutches.

- Crossbar. 1940s. #5 crossbar was a big dumb switch fabric controlled by a distributed set of microservices, all built from relays. Most elegant architecture. All reliable wire relays, no more motors and gears. If you have to design high-reliability systems, is worth knowing how #5 crossbar worked.

- 1ESS - first US electronic switching. 1960s Two mainframe computers (one spare) controlling a big dumb switch fabric. Worked, but clunky.

- 5ESS - good US electronic switching. Two or more minicomputers controlling a big dumb switch fabric. Very good.

The Museum of Communications in Seattle has step by step, panel, and crossbar systems all working and interconnected.

In the entire history of electromechanical switching in the Bell System, no central office was ever fully down for more than 30 minutes for any reason other than a natural disaster, and in one case a fire in the cable plant. That record has not been maintained in the computer era. It is worth understanding why.

[1] https://archive.org/details/bellsystem_HistoryOfEngineeringA...

The more I study the 5E I see it as a multicomputer or distributed system. The minicomputers were responsible for OAM and orchestrating the symphony over time, but the communications are happening across the CM which implements the Time/Space/Time fabric and a sea of microcontrollers. I think this clarification is worthwhile because it drives your point about faults in this computer-era and by extension this (micro)services-era home even more -- it's much less mainframe and more distributed system than commonly chronicled, which can be a harder problem especially with the tooling back then.

It's actually an 8 volume History (I have all 8 on my shelf) 3 were just on switching system - you left out the parallel development to Panel, Rotary.

Museum in seattle also has a working 3ESS (likely the only one left in the world), and have recently added a DMS-10 as well.

> That record has not been maintained in the computer era. It is worth understanding why.

Go on.

Briefly,

The big dumb switch fabric of #5 Crossbar has no processing power at all, but it has persistent state. The units that have processing power all go down to their ground state at the end of each call processing event, and have no state that persists over transactions. The various processing units (markers, junctors, senders, originating registers, etc.) are all at least duplicated, and usually there's a pool of them. Requests "seize" a unit at random from a pool, the unit does its thing, and the unit is quickly released.

Units have self-checking, and if they fail, they drop out of their pool and raise an alarm. The call capacity or connection speed of the exchange is reduced but it keeps working. Everything has short hardware stall timers which will prevent some unit failure from hanging the exchange.

#5 Crossbar has almost no persistent memory. End offices (for connecting subscriber lines) did not log call info. Toll offices did, but that used an output-only paper tape punch. There's so little state in the switch that matching up call start and call end events was done later in a billing office where the paper tape was read.

The combination of statelessness and resource pools prevented total failure. Errors and unit failures happened occasionally but could not take down the whole switch.

There's plenty of info about #5 Crossbar on line, but 1950s telephony jargon is so different from 2020s server jargon that it's not obvious that #5 Crossbar is a microservices architecture.

Thinking about this, this is why Erlang, designed for phone switches, is built around small processes which can fail and be restarted.

The Microcenter in Cambridge (MA) finally updated their sign to modernize the rainbow Apple logo a few years ago. I hope it's stashed somewhere, to me it's more iconic than the Citgo sign a few miles away. They have added some components and kits but it doesn't fill the yawning void left by You-Do-It Electronics shutting down a year ago, or Radio Shack's slow motion demise.

>>it doesn't fill the yawning void left by

Or Gateway Electronics in St Louis

I just added strips of fake fur to the straps my boring old helmet to diffuse the wind noise the same way a "dead cat" cover on a microphone does. They look a bit like muttonchops which is a bonus as far as I am concerned. I use wraparound bone conduction headphones that don't block my ears. I would be afraid of losing an expensive earbud.

$4500 is ten or more of my homebrew 750 watt electric mountain bike originally built in 2004. I just repowered with LiFePO4 after 10 years in storage and the new batteries really pull. It has a front hub motor with a throttle control limited to 20 mph. My commute is 10 miles, 6 on a dedicated bike path. Life is good.

My local bicycle dealer has models in the window up to 15k$. There’s a market for such priced products.

Those are high performance mountain bikes with carbon fiber frames, top of the line components, carbon wheels. This is an aluminum city commuter and 4.5k is at the high end of that class of ebike.

My tern gsd (cargo e-bike) was in this range and it was totally worth it. Not sure I'd feel the same about a basic commuter bike though.

Terns are great bikes

the problem with $5-$15k bikes is you can't actually use them in the USA as they'll be stolen. You can commute if you have the place to keep it secure. You can not stop for some shopping on the way home though as you'll lose your bike.

The last bike I had stolen was one I paid $100 for.

If I commuted via bicycle in an area with frequent larceny, I’d simply take it inside to my cubicle, which is surprisingly easy. Currently I live in a low larceny area so I simply leave it outside of the office, unlocked.

Just like $0-$5K bikes: it's not like a homeless junkie is going to leave your bike alone if it's just $3K or even $300.

My $200 rusty ebike has been parked outside for 18 months in central London without problems. I take the battery in. The homeless junkie would have to get an angle grinder to cut two D locks, figure out how to buy the battery which costs $300 and is only available from decathlon, somehow try to make a profit out of the whole operation which I don't think I could myself and so on.

It's actually cost me about another $500 in maintenance getting the various bits that pack up replaced but it's a good theft deterrent.

This might have something to do with London not being in the USA?

I guess it varies by location but we have homeless druggies and bike thieves here too. I think old rusty stuff not being very attractive to thieves is fairly universal.

Do you also have homeless tent cities with thousands of stolen bikes in different states of decay piled around?

No. We don't have that one. Although the place still has issues https://www.reddit.com/r/londoncycling/comments/1hfo5ij/how_...

You might have different problems but you don't have the American problem with bike theft. Homeless here steal bikes regardless of their price and condition.

> your work probably provides a place to safely store it.

They get stolen anyway, know some guys it happened to.

Right, the thieves will shoulder surf or pick a lock to get into the "secure" office building storage area. Happens all the time and the police won't bother to investigate.

Oh, clearly. But for that money I'd buy a really nice BMW i3 REX. Obviously not an option for everyone.

Why would anyone use Dropbox when you can self host a linux VM with a file share using a VPN to tunnel?

What kind of capacity from your LFP battery? Is it diy built? I did one in the spring 16S with 25Ah cells and it's been amazing since. Only problem is it's a bit too big to fit anywhere I'd like it to. I have to mount it on a rear rack

I am using 3x 12v 185wh batteries in series. Realistically I can count on around 500wh. They are only 3 lbs each and fit neatly within the frame of the mtb. I don't like having them up on the rear rack, they tend to make the tail of the bike wag a bit compared to low and centered.

https://old.reddit.com/r/ebikes/comments/1o0qthk/dynagirl_ri...

I just 3d printed protective covers for them last week when marketing turned their back on the new Bambu printer.

Nice

I have a big commute and in the (Canadian) winter my old 750Wh was sometimes not up to the task. So I went wildly over the top and built a huge cap battery. I never need to worry now

I don't plan to bike commute in the winter, it is too dark AM and PM. Have you tested your LiFePO4 batteries in low temperatures?

The components are all probably very junky, if everything can be had for $450

Sure if you can't DIY. It's a 20 year old Fuji chromoly-frame mountain bike with Shimano components. My biggest expense was new batteries, followed by heavy duty e-bike brake pads. What did you pay to build yours?