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原始链接: https://news.ycombinator.com/item?id=40387318

在 90 年代末，用户从当地有线电视公司获得了数字电话线并将其连接到旋转电话。尽管预测互联网协议 (IP) 可以通过任何媒体（包括湿弦）传输信号，但用户还是考虑将其用于学生项目。然而，由于反响不佳，他们等了几年才有学生进行这项尝试。通过实验，该团队发现锡罐由于不需要的共振而不适合，并找到了两种有效的方法：以琴弦的固有频率发出开/关信号，或者在保持强信号水平的同时远离它。虽然成功了，但学生缺乏足够的时间进一步探索。这个故事还提到了那个时代一个家庭存在多条电话线，尽管物理线对较少，这可能是由于频分复用的原因。此外，还有一次地下公用设施安装错误造成中断，导致当局意外造访的情况。后来的反思揭示了技术的进步，例如通过使用各种标准和协议提高数据传输速率，从而在无需重大基础设施改进的情况下实现高速连接。尽管在今天看来似乎很不寻常，但由于资源和技术有限，早期提供可靠互联网服务的尝试在很大程度上依赖于创造性的解决方案和独创性。

100 Mbps Ethernet over barbed wire was demonstrated back in 1995. [0]

"Only four properties really affect the performance of most digital transmission structures. The "big four" transmission-line properties are impedance, delay, high-frequency loss, and crosstalk." Dr Johnson then goes to describe these properties in barbed wire.

0: https://www.sigcon.com/Pubs/edn/SoGoodBarbedWire.htm

P.S. Yes, this is the Dr. Howard Johnson of the famed "High-Speed Digital Design" book.

“ Each house had its own distinctive ring—two short one long, for example—and it was considered impolite to listen in on another's call.”

https://en.m.wikipedia.org/wiki/Party_line_(telephony)

A party line! Our cabin still has a grandfathered one with the distinctive ring. I think we pay 1/4 of the regular rate so we keep it despite everyone having a cell phone now.

I don’t think there’s anyone else on the line.

Got a funny spam call with a recording for some miracle septic tank treatment. It asked me to press 1 for more information and I can’t do that on a rotary phone. Scammers don’t understand their target market. (We also don’t have septic system, just an outhouse.)

> It asked me to press 1 for more information

If you have absolute pitch, and have a friend with absolute pitch (and I mean absolute frequency really not pitch), and are both freaks who can sing perfect sine waves... you could sing the dual tone for number 1 (697 Hz + 1209 Hz).

Since at this point we are talking about mutant alien phreaks, you should also be able to do overtone singing and squeeze out a 2 or a 3 column on your own which are 10% flat and sharp from the 2nd order harmonic of the first row 697 Hz.

Happy phreaking

> freaks who can sing perfect sine waves

Whistle, don't sing. Try it with a realtime analyzer which shows the fundamental being far more prominent than any harmonics above it, which means it's close to a sine wave. Then sing various vowels which will show as a series of harmonics whose amplitude ratios change per vowel but are never reduced nearly as much as when whistling.

I got a 'digital phone line' through the local cable company installed about a decade ago. I had it hooked up to a rotary phone and I was able to dial out just fine with it.

Pulses can be detected by modern stuff just fine, when said detecting occurs on the same electrical circuit that the phone is connected to (for example, an analog to VoIP interface). They just can't be detected on some other circuit that has only the audio, for example when a conversion to digital audio has occurred. Only tones make it through such conversion. And while a VoIP interface capable of detecting pulses will happily do so (and convert them into something more useful) when it is presenting a dial tone, it won't do a conversion to DTMF for the benefit of IVR [0] mid-call. Devices specifically design to perform this task, however, will!

[0] https://en.m.wikipedia.org/wiki/Interactive_voice_response

I remember Van Jacobson saying in the early 90s that IP would work over two tin cans and a piece of wet string. For several years, I set this as a possible student project, partly as a joke, but it was had no takers for quite a few years. Then in 2009 a student finally took me up on the offer. The main things we learned were that the tin cans were a bad idea (undesirable resonances), and that you could either do on/off coding at the string's resonant frequency, or try to stay well away from the resonant frequency, but then the signal strength was very low but you could distinguish multiple frequencies so do more interesting coding. In the end the project was successful, but the student ran out of time before he could really investigate in great depth.

What an awesome project!

Was the bandwidth that narrow at the resonant frequency? Intuitively, I wouldn't have expected that "wet string" has a high Q. :)

If I had been your student, I would have had great fun with it.

This is funny. About 10 years ago, I had bonded ADSL for my internet (yay sonic.net). The idea being that two lines bonded together would have twice as much bandwidth as a single line. Each line had a max rate of 20Mbps, so I had a max of 40Mbps combined. It worked pretty well initially, but over time it degraded horribly. Because you could see stats for each line independently, I could tell that one line was operating at ~18Mbps and the other was around 2 and there was a lot of error recovery going on. After much complaining, I found out that one line was degraded and somehow reacted to rain (water got in the trunk somehow). And no, AT&T wasn’t going to fix the broken line.

I chose to just use the single (good) line.

So, yes, I can confirm this does work in the field… but with about as much practically as you’d expect.

Another issue with DSL bonding is crosstalk, which is pretty bad in many cases of telco wiring.

10 years ago there was a huge amount of surplus Cisco 1700s with SHDSL line cards (apparently coming from Czech government's project to connect every school to internet in early 00's) and we had huge spool of flat phone cable that was left over from earlier project. So we had the bright idea to wrap ethernet trafic in AAL5, pass that over SHDSL and use that as an LAN for anime convention. Interesting observation from that it matters whether the cable is coiled or un-coiled. We built and tested the whole network in a lab (with coiled cables), it worked well, the G.991bis bonded links synced up at 6Mbps with two pairs and everything was good. We labeled everything and we built the exact same thing (including same cables) at the venue and the links will not go above 1.5Mbps and were frequently losing sync. Disabling the second bonded pair caused it to work reliably at 2Mbps. (Back then, we did not need that much of bandwidth, it was essentially for few SCCP phones, some IP tunelled serial ports and ssh)

Well, next year we bought two boxes of Cat5 cable and switched to native ethernet (and today the backbone spans are 10G fiber, as it also carries video streams).

Ah yeah, if it was just flat cable instead of twisted pair or coax, coiling the cable could have made a massive difference in the characteristics. Interesting that coiling worked better...

I’m always a bit amazed when every home has 2 lines running to it, and probably 99% of those second lines never get used, but telcos figured it was worth it for those occasional 2nd lines/fax lines or redundancy instead of ever needing to run a 2nd pull.

Is this just a North America thing or an everywhere thing?

Only two? Around 1995 we had four phone lines: home, home office, fax, and modem. There were only three physical pairs, so two of the lines (I think the voice lines) came off one physical pair with a frequency division splitter.

Some time later I saw a Pacific Bell truck and crew trenching the street. (We had underground utilities.) I excitedly asked them, "Are you running fiber?" "No, just more copper."

I guess they saw the demand for lots of copper lines per house and decided to meet it!

The underground phone lines did lead to some excitement one time. Their water sealing wasn't very good, and after a heavy rain the line would get noisy and clicky. During one of these episodes, we got a loud knock on the door: "San Jose Police! Open up!"

I ran to the door and asked what was going on. One of the officers said, "We got a 911 call from this address. The dispatcher couldn't hear anyone on the line, and no one answered when they called back. So we're required to come out and investigate the situation."

I replied, "That's odd, neither of us called 911. Oh... I think I know what may have happened. Come in and I'll show you."

We went to the kitchen and I put the wall phone (remember those?) on speaker and had the officers listen. It was clicking up a storm!

Then I asked them if they remembered the old rotary phones (they did). I explained how the phone dial worked by breaking and making the circuit N times for each digit you were dialing. And it must have been that in that flurry of clicks that the circuit was broken nine times, then once, then once again.

In India it was pretty common for phones put in semi-public locations to have a lock on the dial to stop people making outgoing calls. But if you were motivated enough, you could still dial out by tapping the number out on the switch hook.

> Some time later I saw a Pacific Bell truck and crew trenching the street. (We had underground utilities.) I excitedly asked them, "Are you running fiber?" "No, just more copper."

During the Australian NBN^^ rollout. Where I used to live was on the border of a FTTC and a coax/DOCSIS one. My street had no pre-existing cable TV cable so you'd think no brainer to lay fibre. Nope, brand new coax. And because the street had no coax that meant no homes had an existing cable so they had to trench every driveway to connect it to the street. It would have been an absolute no brainer to run fibre then use the existing phone lines up driveways to their homes. Cheaper, and an easy upgrade path to full fibre. This was 2019.

^^Australia built a national broadband network. It was originally designed to be all fibre (except for remote places over satellite etc), but politics happened and it was changed to a multi technology mix which included DOCSIS, fibre to the node then vdsl for the last km or whatever, or fibre to the curb and vdsl up your driveway. And the government entity building it NBN was buying up old copper phone lines and coax.

In Germany, the government of Helmut Schmidt (social democrats) planned to implement an optical network to every house in west Germany in 1981. In 1982 Helmut Kohl became chancellor, cancelled the 30 year plan and what we got was coax lines for cable TV. Thanks a lot, just imagine where Germany could be today … to be fair, a significant part of households gets their internet connection over the cable tv networks, but still it was a dumb decision.

German article on the matter:

https://netzpolitik.org/2018/danke-helmut-kohl-kabelfernsehe...

Don‘t forget that Helmut Kohl was also sharing a bed with the television industry at that time when optical networks couldn’t transmit analogue television.

If you go everywhere, you'll rapidly find countries where landlines didn't get meaningful penetration outside of metropolita areas at all.

But even in North America, I don't think every home had two pair all the way to the central office. They might not even all have two pair all the way to the crossbox [1]. It was not uncommon to order a 2nd phone line, and not be able to get it, because there weren't any available pairs on your pole. Especially if your neighborhood was established well before the explosion of the internet and fax in the mid to late 90s.

[1] https://en.m.wikipedia.org/wiki/Serving_area_interface

Very common across Europe too. Makes sense, running a second line is so much labour that only a few would have to order it to make the extra cable cost for everyone worth it.

We had a serious degradation in line speed every time it rained. We rang our isp (Andrews and Arnold, the same as in the original post), and it was fixed in a week. Thanks A&A!

I think the secret is that they are small enough to be a constant hassling nuisance, so OR now knows that they’ll just get grief until it’s done. Squeaky wheel and all that :)

Sewer are properly buried, Rogers cables are just thrown around with maybe a bit of dirt on top of it was a good day. I redid a wall in my backyard last year that is close to a Rogers box, I removed ~15 old cut cables from the ground.

Man if there's one thing I can credit bell for, is that they really pushed for fiber. Before we had bell fibe here (for a shockingly reasonable price) in Montreal, we were stuck with absolute trash DOCSIS for so long. Every time the revisions increased ,the speeds would be nominally faster but in reality came with trash stability and peak time performance.

I'm sure DOCSIS is great for what it is, and in fact it's extremely impressive what it can do with existing cable lines, but the second biggest player here (Videotron) basically milked it dry. Again it's weird to praise them but Bell invested in wiring up the entire city and suburbs and I can get 3gbps symmetrical GPON FTTH for the price that 150mbps used to go for not even 3 years ago. I blame DOCSIS in a way because it made players with existing lines extremely complacent

Yeah, ADSL being so good at handling a crappy physical medium is both a blessing and a curse. If it weren't for these technologies we would have probably had to replace those rusty copper pairs decades ago for fiber optics. Instead the protocols continued to improve (ADSL2, ADSL2+, VDSL, VDSL2+, vectoring, supervector...) and allowed ISPs to provide usable network speeds without spending a cent on improving the infrastructure.

You still need to bring fiber relatively close to the building, so it's not exactly happening without spending a cent.

Fun fact: Switzerland operates the only significant G.fast deployment in the world. The technology was such a flop that Huawei stopped making the hardware.

G.fast covers over a million premises in the UK. Extremely low take up partially as they started acceleration of FTTP build pretty much at the same time.

By the way most of the fibre needed to connect the FTTC/VDSL/GFast cabinets was already in the ground and they just needed to splice into it, as it was there for exchange to exchange backhaul, and leased lines. It's the final ~500 metres that's the expensive part of installing FTTP, as that has to be new and there is probably not a lead in duct that is clear so means climbing poles, clearing duct, or new trenching.

I'm pretty sure G.Fast was never actually deployed for NBN FTTC. It was planned/announced in 2021-2022, but eventually NBN came about their senses and decided to do FTTC -> FTTP upgrades like they're doing for FTTN.

CenturyLink/Lumen has been using G.fast for most new FTTH deployments since 2016. They still install fiber to the outside of the house though, it's mostly about avoiding needing the installer to mess with wiring in the walls of existing houses, and being able to reverse power the outside node, instead of needing an outlet outside.

I think that was an extremely small rollout. I didn't even know they ever deployed it until I checked when I read your comment. The upgrade path is full fibre, which you can now finally get in alot of places.

> Fun fact: Switzerland operates the only significant G.fast deployment in the world.

Nope. In Germany, M-net (Munich) and NetCologne operate massive g.fast networks, and if you don't want Huawei, go for Adtran's 516 lineup on the ISP side and AVM on the CPE side.

My friends in Munich or the Ruhr region don't seem to know of any "massive" G.fast availability... which in any way is very late to the party. But I stand corrected.

I didn't know about network equipment from other manufacturers, not sure why we're stuck with Huawei here, but it's a dead end. The plan is to migrate as many G.fast subscribers as possible to FTTH in the next 5 years, and eventually to mmWave 5G in a few corner cases.

When I still lived in Munich, I had M-Net since pretty much their inception. ADSL first, later fiber. It was always great, and on the very few occasions that I had problems, I usually directly got a technician on the line who knew exactly what they were doing, instead of a few layers of help desk peoples fielding calls.

Zyxel and Fast Networks are also good on the ISP side (Not sure Fast Networks is still a thing - website seems to be down - but I run one of their DSLAMs and am happy with it)

My home internet connection is VDSL2 and I see very consistent 100Mbps+ over the original phone cables of my house, which is built in 1933.

Actually serious question: Would this work as fallback tech in a war ridden zone? Not over wet string, but over something like reclaimed copper wire from whatever is around. Suppose laying fiber would be too risky and is too fragile, cannot be patched up in the field.

Fiber can be patched, but it take a lot more than just twisting the ends together like you can with copper. Usually they have a portable fusion splicer in case of a fiber cut and can at the very least fuse a length of fiber on each end of the break so it can pass light again.

My wife and I have been looking for a property out in the rural parts of Michigan. One of the homes we went to visit with our realtor had left out a laptop computer in order to test the internet. Damn thing has ADSL and gets 2.2mbps down lmao. I do not miss the ADSL days.

My home used to get 4 Mbps down until water got into the paper insulated trunk lines and became unusable. My new pair maxxed out at 2. So happy that all my broadband internet surcharges were spent on improving the customer experience.

The Thumb area has been getting direct home fiber through a power company co-op. Been pretty great, I got mine like 6 months ago.

Before this we didn't even get DSL because the lines were so degraded.

I started calculating the bandwidth for a continuous stream of carrier pigeons carrying 256GB flash drives, at different frequencies.

But the latency and loss rate would make it all worthless.

Latency definitely, but imagine pigeons carrying 8TB M.2 PCIe Gen-5 sticks strapped to their backs. That's some crazy throughput rivaling most domestic internet connections.

Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway.

https://www.reddit.com/r/vintagecomputing/comments/9of84w/ne...

Rings true for me. In my younger days I was "privileged" to catch an early morning flight to San Jose with a stack of tapes that I then drove to Palo Alto. All because a RAID array had gone kaput and tapes in a carry-on provided better bandwidth than the upstream from the office where our backups were.

I remember back around '98, there were a bunch of product that you could get that would turn the electrical wiring in your house into an ethernet network. You'd plug the thing in and then as long as the other end was on the same breaker, it would work great. I used it in my apartment to get network from one room to the other.

This reminds me of that.

ah i don't know. A 2023 (~cheap) car reverse camera for a videorecorder with (looking like) usb protocol on the wire between, does not work if cable is more than 5m. Or if it is another 5m cable (utp, ftp, 4x1mm, combination, whatever. Only that initial one). Period.

Kind of by necessity the nature of ADSL, how else are you gonna offer broadband internet over the (by now) rotten infrastructure you were privatized into "owning". How can you squeeze as much profit (and as many bits per second) as humanly possible out of it, without ever investing a single cent more into your infrastructure than absolutely necessary? By relying on ever more absurd hacks.

A small world. I checked out his site and discovered I worked with his wife. He’s the Finch in Coleman Finch. Rachel is you are reading this, Hi! Hope you are well.

Not entirely a bot and not entirely old content.

I’ve got a lot of good stuff in my link log https://dotat.at/:/ so I thought it might be fun to share a few retro classics. There has been some good discussion, so it seems to be worth it.

Almost certainly--judging by their submission timestamps, they appear to never sleep. I guess you can farm a lot of karma by just re-posting old popular posts.

There are bots on HackerNews, 3 kind of them:

- Comments bots (like on other threads), usually to promote a crypto-thing.

- Submissions bots to farm karma (likely one of them here).

- Upvotes bots (taboo).

Recent karma is necessary for upvoting other posts, as there is a system which makes you can't upvote if you didn't get upvoted yourself.

If you can upvote some posts on HackerNews (as it would be on Reddit) you can help people make a lot of money, but again, you need recent karma.

> After 13 years you have found the password to your account

Subtle :)

> logged in to call OP a bot for some reason?

Why did the Persona call the Kettle black?

Unsee!

> Why did the Persona call the Kettle black?

> Unsee!

???

> Subtle :)

It's too subtle for me, care to explain?

I don't know if your comment is trying to point out the similar account ages, but that's not the point at all. sph has a zillion comments over 13 years, and owenphen has just this one. There is no pot calling the kettle black.

My comment is supporting sph.. (whose comment shouldn't be flagged). A known human-by-profile fanf2f is accused of bot-hood by an unknown actor burning a 13-year (2011 vintage) nym/persona. sph calls that out without breaching HN guidelines.

> ???

2011 was a good year for grapes, er broadcasting, https://uscpublicdiplomacy.org/blog/reforming-smith-mundt

https://en.wikipedia.org/wiki/The_City_%26_the_City

  A denizen of one city must dutifully "unsee" (that is, consciously erase from their mind or fade into the background) the denizens, buildings, and events taking place in the other city – even if they are an inch away. This separation is emphasised by the style of clothing, architecture, gait, and the way denizens of each city generally carry themselves.

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