10 ms·

56k modems relied on digital trunk lines

180 points by beardyw 2y ago

immibis 2y ago
Isn't it the opposite of the headline? Modems were hamstrung by digital phone lines you didn't know we had. One final trick allowed them to match, but not exceed, those digital lines.
- ranger_danger 2y ago
  To me it looks like the article is largely told from the perspective of ISPs connecting themselves between each other, and how the constant analog/digital conversions between carriers were causing problems sustaining the 56k data rate that the (analog) last mile was always capable of... and how converting their internal systems and backhauls to digital solved that issue.
  - telotortium 2y ago
    Exactly. More specifically, Internet servers in data centers connected themselves to the IP network, not the phone network (not surprisingly), so they almost always had an uplink significantly faster than 56 Kb/s. And the analog local loop had encodings that could transmit at 56 Kb/s. But these encodings were not compatible with the analog-digital conversion used in phone network backbone. While today you'd probably expect that the IP network could connect to every phone branch office where the local loops were connected to the phone network, that wasn't necessarily the case - Internet data would usually have to travel some of its way over the phone network backbone, with the problematic digital encodings. V.90 and related standards allowed the phone network to accept the digital data directly from ISPs and send it in digital form to the branch office, without attempting a digital to analog to digital conversion to inject it as digital voice into the phone network. That's why the upload speed couldn't be improved via this method - it would still need to undergo analog-digital conversion to travel across the phone network to the ISP where it could enter the IP network. (V.92, a later standard, improved upload speed to 48 Kb/s via fancier signal processing trickery that could survive the digital voice conversion.)
    - hylaride 2y ago
      All the early metropolitan or long-haul fiber (mostly SONET) networks were digital aggregations of various circuit-modes (DS*) in those days. It made sense since the phone network was pretty much the only long haul network around and even the pure-IP networks didn't yet have enough of a market for alternative protocols. I've been out of the core-networking loop for awhile, but my understanding is that most modern long-haul networks are ethernet over OTN. The phone companies had enormous sway over the development of these longer haul protocols. The debate around packet sizing almost always favoured smaller cells (especially ATM), which was more ideal for voice - with the added overhead for more standard IP packets. They were also often very connection-oriented, with all the extra equipment overhead required.
      - immibis 2y ago
        Circuits meant for IP didn't convert digital to analog and back unless they had to share the line with a phone at one end. If you had digital connections to both ends of a digital circuit, you'd use all the bits for data.
        hylaride 2y ago
        I'm a little confused - I didn't say that? I said that a lot of the circuits meant for IP still had to use (digital) protocols designed for voice.
- topranks 2y ago
  Yeah kind of. The u-law sampling of audio to produce the 64kbit audio channels in ISDN isn’t good for encoding a signal created by a modem. But if it was a direct copper pair end-to-end then attenuation and electrical other characteristics would have made it hard to achieve the higher speeds, this is the Shannon limits they mention.
- chipsa 2y ago
  The analog lines before digitalization were limited to 8kHz bandwidth. This is because to deliver a circuit between two points, the system generally figured out which bit of bandwidth wasn’t in use and frequency shifted the entire connection into that band.
chrsig 2y ago
ah, good ol' capping out at 26.4kb/s...until 2005
- p1mrx 2y ago
  We were stuck at 26400 until 2001, when DOCSIS reached the area. I recall hearing speculation that a https://en.wikipedia.org/wiki/Pair_gain https://en.wikipedia.org/wiki/Pair_gain was the cause. Around 2000, I saw a crew pulling new phone lines through the neighborhood because everybody was getting a second line and they were running out, but even after switching to the new copper, we were still stuck at 26400. 20+ years later, it looks like 25/5 ADSL is now available at that address, so the new copper wasn't a complete waste.
  - bigbuppo 2y ago
    More than one A-to-D conversion would knock it down to no more than 33.6. Pair gain units would cause problems. Bridge taps and load coils could also be problematic, but that was much more of a concern on DSL. Older amplifiers had very narrow filters and would also cause slow speeds. Echo cancellation hardware would ignore the in-band signal to get out of the way and cause problems. As there was no legal compulsion to get them to act Bellsouth wouldn't do anything to help slow connect speeds for internet dialup. The trick was to lie and say you were having problems sending a fax, then they were required to act. They wouldn't even worry about testing first, as it was quicker to just re-engineer the line to the best practices of the day.
    - kstrauser 2y ago
      I worked tech support at an ISP. Occasionally customers would call in from their brand new subdivision to complain about our crummy service. “This house is brand new and we only get 26.4. What’s wrong with your system?” And then I had the satisfaction of explaining that Ma Bell cheaper out and used pair gains to build out their block cheaply. Sorry, call them to complain, or move.
  - chrsig 2y ago
    i recall some of the same speculation. in my case we wound up getting a satellite connection, with a wonderful 600ms round trip time.
sureIy 2y ago
That reminds me of my short time with ISDN and the amazing availability to receive calls on the second line without forcing me offline.
- stuff4ben 2y ago
  That 128Kbps on ISDN was the like the gold standard back then! I knew some sysadmins who had that installed to their homes so they could be available at any time. All paid for by the company they worked for.
  - wkat4242 2y ago
    Yes but with channel bundling you also had to pay twice. One channel was only 64k.
  - js2 2y ago
    I was one of those SAs, circa 1998-2000. We also had an on-call kit with a Nokia Communicator so we weren't completely stuck at home while on-call. Fast-forward to 2025, and I now have dual 1Gbps symmetric fiber connections (AT&T, GFiber) into my home from opposite sides of the house. (It's totally gratuitous and I'll probably cancel GFiber in a few months, but I wanted to have it wired up so I could more quickly start service in the future.)
  - fatnoah 2y ago
    > All paid for by the company they worked for. One of my internships in college was at Sun Microsystems in the org that provided this connectivity to employees. My job was to automate pushing updates to connection software and modem firmware down to clients, but I ended up doing a lot of technical support as well.
  - hylaride 2y ago
    Ha! My mom worked as a build engineer at BNR (later Nortel) in the 1990s and we got a free 2nd phone line for her to dial into work (99% used by me and my brother for internet). She could have gotten ISDN had it been available in our small town, but alas...
  - 2y ago
wkat4242 2y ago
Yes these modems were almost-ISDN (minus the razor fast call setup). And required a full digital backend to work. They could only do 56k6 in one direction, to the user too. But they were made for internet access so that didn't really matter.
- icedchai 2y ago
  ISDN had much, much better latency than even 56k modems. Modems were around 150ms minimum. ISDN was often in the sub 20 ms range. This made a big difference for chatty protocols like HTTP, telnet, etc.
  - hylaride 2y ago
    Or gaming. I never got good at quake because of it. IIRC they added hardware compression to the later versions (I think starting at 33.6?) that added latency, too.
  - wkat4242 2y ago
    True, though in those days that didn't really matter except for gaming. The bandwidth was so low and the web going in content so fast that the local uplink bandwidth was usually congested causing delays due to queueing and pending acknowledgements. Switches and routers weren't quite as optimised for low latency either. A lot of local networks were still 10base2 (or 10baseT with hubs, not switches) so collissions added further latency. What I loved the most about ISDN was the quick call setup. Took like 1 second max and you had a 64kbit channel. 56k modems went through a dialling phase, a connection phase, endless handshaking...
- ljf 2y ago
  I remember my brothers friend in rural Portugal having one way satellite Internet back in the 90s to very early 00s - you used a standard dial up for the upstream, but with a satellite dish got much much faster downloads. Blew my mind that you could go out one way and receive another and still get a functioning (and fast) connection.
  - 2y ago
OhMeadhbh 2y ago
Yup. I worked on the "Rapport" series of switches at Bell Canada. It was DS1 (Digital Signal 1) out one end and a rack full of Zyxel modems on the other side. The idea was RBOCs (Regional Bell Operating Companies) would put these in their CO (Central Office) and terminate 56k modem signals over the analog "last mile" loop to the customer premises and then do Frame Relay over the phone company's data lines to your ISP. I know Southwest Bell bought a number of them and stuffed them in a closet north of downtown Dallas. During the install I remember having to explain what Ethernet was to their techs. They were EXCELLENT at phone standards, but had decided the data world was threatening and were determined to never learn anything about it. I know that between around '93 and '97 if you dialed AOL from D/FW there was a good chance your call would be terminated somewhere within a mile or two of your house and the bits flowing between your Compaq Presario and AOL would be sent digitally from the local CO to AOL's data center in Sterling, VA. This line of business was (of course) destroyed by consumer DSL and cable modems, but for about 5 years it was fairly popular with the phone companies. ISDN at the time was a bit pricey for most households and a modem is a one-off purchase. Most people I knew using things like AOL or CompuServe were using a hand-me-down 36k modem on a crappy 33MHz 486sx running DOS / Win3.1 / Win95 and were fairly cost-sensitive.
- plorg 2y ago
  Revealing my ignorance here, but was (is?) there a telephone equivalent of anycast such that, say, the 1-800-... Or 1-900... numbers would be routed differently based on location? My basic knowledge of phone systems suggests it would at least be possible.
  - iptel 2y ago
    Absolutely, when call hits local switch it can be terminated differently based on its location. Particularly pertinent for modem based services in the 90s. A single national dialup number would terminate on 100s of local pops and routing decisions would be done to keep traffic as local as possible.
    - timthorn 2y ago
grishka 2y ago
Now I'm curious about how this worked in my city where we most definitely didn't have anything digital to our phone system at the time. As in, you had to use pulse dialing, and sometimes, rarely, your calls would glitch such that you would hear someone else talking over your call. Yet I remember consistently getting 40-something kbit over that.
- kragen 2y ago
  LZW?
oldandboring 2y ago
I remember some ISPs allowing you to "shotgun" two 56k modems for double the speed! Like some other commentors I also fondly remember ISDN. Overall I found it to be finicky. Sometimes one channel would just drop, even if a phone call wasn't coming in. And, in order to use a traditional analog phone with your ISDN line, you needed a special powered "TA" adapter or the phone wouldn't ring when a call came in.
hackthemack 2y ago
I have to wonder if the cap (theoretical) on the copper wires was more because of the technology standards in play at the time. Surely the copper wires could have handled more if they did not have to carry voice communication (with the old tech specs of the time) any longer? Ok. Searched around. Here is an article that states old copper could have carried 1 gigabit. https://www.newscientist.com/article/2317040-ordinary-copper-telephone-wire-could-carry-gigabit-broadband-speeds/ https://www.newscientist.com/article/2317040-ordinary-copper...
- mannyv 2y ago
  They did it for efficiency. The observation was that the human voice doesn't use most of the audio spectrum, so they optimized everything for voice. A reasonable decision at the time.
- quink 2y ago
  Of course ancient telephone wiring can carry 1 Gbps. The real question you always, always, always, need to be asking yourself is: Over what distance? Make that distance short enough, as has happened with FTTN, or FTTC deployments in a whole heap of places, you're basically building a network that's, and I'll keep this very brief, subpar. Since you mentioned a UK context there, Openreach rolled out an upgrade that kept the last mile of copper but now just about a decade later they're rolling out Full fibre. Whatever argument copper had, it went out the window near enough a decade ago.
  - quink 2y ago
    OK, had a look through the linked paper. The big graphs, on page 8, tell you that if you decrease the twist length - which would entail relaying all the copper in the entire network, at which point you may as well put down fibre instead - you will get -20 dB at 10 GHz over a distance of 0.5m, 50cm, less than two feet, instead of -25 dB in the worst case. In other words, instead of losing 99.7% of the signal over that distance, it'll only lose 99% of the signal. Sure, it helps, but consider me underwhelmed.
    - 2y ago
Synaesthesia 2y ago
I could tell what connection speed my modem was going to be by the sound of the handshake. There were distinct sounds for all the different modes. I remember us getting our first modeum, it was 800 baud! Then we moved to 2400, 14.4, 33.6 and eventually all the way to 56k.
- bryanlarsen 2y ago
  800 baud? Do you mean 300 baud? 800 baud is not a standard speed so if they did exist you'd have to supply both ends of the connection..
  - Synaesthesia 2y ago
    Oh yeah it was 300!
    - bryanlarsen 2y ago
      Darn, I was hoping it was some sort of oddball thing. Those are always interesting.
timewizard 2y ago
> Using the Digital Signal 0 (DS0) encoding DS0 is not encoding. It's (pseudo) framing. > phone calls became digital with The G.711 encoding in either aLaw or muLaw format.
pimlottc 2y ago
To be clear, this was well known at the time. It was advertised that 56k was for download only and required an ISP that supported it. For those living in rural areas, there often weren’t any local options (long distance was certainly not free in those days). But for those who could get it, it was definitely a big improvement.
kreddor 2y ago
TIL why upload on 56k modems were capped on 33.6k. I always wondered about that. Super interesting stuff! I also remember back in the day that my 56k modem would often only connect at like 48k or so, especially when it was raining. I guess living far out from the city made the connection more noisy?
aa-jv 2y ago
I had made a small career on building Internet Service Providers in California, in the early days, and will never forget how liberating it was to carry my laptop to the Griffith Park observatory with a fully-charged Ricochet modem plugged in, communicating to my house down in Los Feliz, where another Ricochet modem gateway'ed me to the Internet via the house 56k line .. It was truly astonishing to be up there, checking email. A few, what seems very short, years later .. and now it is just normal.
DonHopkins 2y ago
There was a time when 300 and 1200 baud modems cost about $1/baud.
exabrial 2y ago
Man I wish we still had slow connections, given all the dumb crap on webpages these days. Was crazy to think about trying to get your page to load in less than 64k a few years back.
msarrel 2y ago
Yes, and I provisioned them. You could shotgun them. Fun times
deleted 2y ago
[deleted]
sgarland 2y ago
I remember the day we got 56K from our ISP. Our modem was 56K (no idea what model, some internal WinModem), but the ISP was limited to 33.6K. Then one day, the connection screech sounded different, and I excitedly pointed this out. Several seconds later, it connected, and lo and behold, we had 66% faster downloads. The fact that all of this worked continues to amaze me, but then, so do mobile phones. I understand at a high level how CDMA works, but it’s just so insane…

180 points by beardyw 2y ago

Isn't it the opposite of the headline? Modems were hamstrung by digital phone lines you didn't know we had. One final trick allowed them to match, but not exceed, those digital lines.

ranger_danger 2y ago
To me it looks like the article is largely told from the perspective of ISPs connecting themselves between each other, and how the constant analog/digital conversions between carriers were causing problems sustaining the 56k data rate that the (analog) last mile was always capable of... and how converting their internal systems and backhauls to digital solved that issue.
- telotortium 2y ago
  Exactly. More specifically, Internet servers in data centers connected themselves to the IP network, not the phone network (not surprisingly), so they almost always had an uplink significantly faster than 56 Kb/s. And the analog local loop had encodings that could transmit at 56 Kb/s. But these encodings were not compatible with the analog-digital conversion used in phone network backbone. While today you'd probably expect that the IP network could connect to every phone branch office where the local loops were connected to the phone network, that wasn't necessarily the case - Internet data would usually have to travel some of its way over the phone network backbone, with the problematic digital encodings. V.90 and related standards allowed the phone network to accept the digital data directly from ISPs and send it in digital form to the branch office, without attempting a digital to analog to digital conversion to inject it as digital voice into the phone network. That's why the upload speed couldn't be improved via this method - it would still need to undergo analog-digital conversion to travel across the phone network to the ISP where it could enter the IP network. (V.92, a later standard, improved upload speed to 48 Kb/s via fancier signal processing trickery that could survive the digital voice conversion.)
  - hylaride 2y ago
    All the early metropolitan or long-haul fiber (mostly SONET) networks were digital aggregations of various circuit-modes (DS*) in those days. It made sense since the phone network was pretty much the only long haul network around and even the pure-IP networks didn't yet have enough of a market for alternative protocols. I've been out of the core-networking loop for awhile, but my understanding is that most modern long-haul networks are ethernet over OTN. The phone companies had enormous sway over the development of these longer haul protocols. The debate around packet sizing almost always favoured smaller cells (especially ATM), which was more ideal for voice - with the added overhead for more standard IP packets. They were also often very connection-oriented, with all the extra equipment overhead required.
    - immibis 2y ago
      Circuits meant for IP didn't convert digital to analog and back unless they had to share the line with a phone at one end. If you had digital connections to both ends of a digital circuit, you'd use all the bits for data.
      - hylaride 2y ago
        I'm a little confused - I didn't say that? I said that a lot of the circuits meant for IP still had to use (digital) protocols designed for voice.
topranks 2y ago
Yeah kind of. The u-law sampling of audio to produce the 64kbit audio channels in ISDN isn’t good for encoding a signal created by a modem. But if it was a direct copper pair end-to-end then attenuation and electrical other characteristics would have made it hard to achieve the higher speeds, this is the Shannon limits they mention.
chipsa 2y ago
The analog lines before digitalization were limited to 8kHz bandwidth. This is because to deliver a circuit between two points, the system generally figured out which bit of bandwidth wasn’t in use and frequency shifted the entire connection into that band.

chrsig 2y ago

ah, good ol' capping out at 26.4kb/s...until 2005

p1mrx 2y ago
We were stuck at 26400 until 2001, when DOCSIS reached the area. I recall hearing speculation that a https://en.wikipedia.org/wiki/Pair_gain https://en.wikipedia.org/wiki/Pair_gain was the cause. Around 2000, I saw a crew pulling new phone lines through the neighborhood because everybody was getting a second line and they were running out, but even after switching to the new copper, we were still stuck at 26400. 20+ years later, it looks like 25/5 ADSL is now available at that address, so the new copper wasn't a complete waste.
- bigbuppo 2y ago
  More than one A-to-D conversion would knock it down to no more than 33.6. Pair gain units would cause problems. Bridge taps and load coils could also be problematic, but that was much more of a concern on DSL. Older amplifiers had very narrow filters and would also cause slow speeds. Echo cancellation hardware would ignore the in-band signal to get out of the way and cause problems. As there was no legal compulsion to get them to act Bellsouth wouldn't do anything to help slow connect speeds for internet dialup. The trick was to lie and say you were having problems sending a fax, then they were required to act. They wouldn't even worry about testing first, as it was quicker to just re-engineer the line to the best practices of the day.
  - kstrauser 2y ago
    I worked tech support at an ISP. Occasionally customers would call in from their brand new subdivision to complain about our crummy service. “This house is brand new and we only get 26.4. What’s wrong with your system?” And then I had the satisfaction of explaining that Ma Bell cheaper out and used pair gains to build out their block cheaply. Sorry, call them to complain, or move.
- chrsig 2y ago
  i recall some of the same speculation. in my case we wound up getting a satellite connection, with a wonderful 600ms round trip time.

sureIy 2y ago

That reminds me of my short time with ISDN and the amazing availability to receive calls on the second line without forcing me offline.

stuff4ben 2y ago
That 128Kbps on ISDN was the like the gold standard back then! I knew some sysadmins who had that installed to their homes so they could be available at any time. All paid for by the company they worked for.
- wkat4242 2y ago
  Yes but with channel bundling you also had to pay twice. One channel was only 64k.
- js2 2y ago
  I was one of those SAs, circa 1998-2000. We also had an on-call kit with a Nokia Communicator so we weren't completely stuck at home while on-call. Fast-forward to 2025, and I now have dual 1Gbps symmetric fiber connections (AT&T, GFiber) into my home from opposite sides of the house. (It's totally gratuitous and I'll probably cancel GFiber in a few months, but I wanted to have it wired up so I could more quickly start service in the future.)
- fatnoah 2y ago
  > All paid for by the company they worked for. One of my internships in college was at Sun Microsystems in the org that provided this connectivity to employees. My job was to automate pushing updates to connection software and modem firmware down to clients, but I ended up doing a lot of technical support as well.
- hylaride 2y ago
  Ha! My mom worked as a build engineer at BNR (later Nortel) in the 1990s and we got a free 2nd phone line for her to dial into work (99% used by me and my brother for internet). She could have gotten ISDN had it been available in our small town, but alas...
- 2y ago

wkat4242 2y ago

Yes these modems were almost-ISDN (minus the razor fast call setup). And required a full digital backend to work. They could only do 56k6 in one direction, to the user too. But they were made for internet access so that didn't really matter.

icedchai 2y ago
ISDN had much, much better latency than even 56k modems. Modems were around 150ms minimum. ISDN was often in the sub 20 ms range. This made a big difference for chatty protocols like HTTP, telnet, etc.
- hylaride 2y ago
  Or gaming. I never got good at quake because of it. IIRC they added hardware compression to the later versions (I think starting at 33.6?) that added latency, too.
- wkat4242 2y ago
  True, though in those days that didn't really matter except for gaming. The bandwidth was so low and the web going in content so fast that the local uplink bandwidth was usually congested causing delays due to queueing and pending acknowledgements. Switches and routers weren't quite as optimised for low latency either. A lot of local networks were still 10base2 (or 10baseT with hubs, not switches) so collissions added further latency. What I loved the most about ISDN was the quick call setup. Took like 1 second max and you had a 64kbit channel. 56k modems went through a dialling phase, a connection phase, endless handshaking...
ljf 2y ago
I remember my brothers friend in rural Portugal having one way satellite Internet back in the 90s to very early 00s - you used a standard dial up for the upstream, but with a satellite dish got much much faster downloads. Blew my mind that you could go out one way and receive another and still get a functioning (and fast) connection.
- 2y ago

OhMeadhbh 2y ago

Yup. I worked on the "Rapport" series of switches at Bell Canada. It was DS1 (Digital Signal 1) out one end and a rack full of Zyxel modems on the other side. The idea was RBOCs (Regional Bell Operating Companies) would put these in their CO (Central Office) and terminate 56k modem signals over the analog "last mile" loop to the customer premises and then do Frame Relay over the phone company's data lines to your ISP. I know Southwest Bell bought a number of them and stuffed them in a closet north of downtown Dallas. During the install I remember having to explain what Ethernet was to their techs. They were EXCELLENT at phone standards, but had decided the data world was threatening and were determined to never learn anything about it. I know that between around '93 and '97 if you dialed AOL from D/FW there was a good chance your call would be terminated somewhere within a mile or two of your house and the bits flowing between your Compaq Presario and AOL would be sent digitally from the local CO to AOL's data center in Sterling, VA. This line of business was (of course) destroyed by consumer DSL and cable modems, but for about 5 years it was fairly popular with the phone companies. ISDN at the time was a bit pricey for most households and a modem is a one-off purchase. Most people I knew using things like AOL or CompuServe were using a hand-me-down 36k modem on a crappy 33MHz 486sx running DOS / Win3.1 / Win95 and were fairly cost-sensitive.

plorg 2y ago
Revealing my ignorance here, but was (is?) there a telephone equivalent of anycast such that, say, the 1-800-... Or 1-900... numbers would be routed differently based on location? My basic knowledge of phone systems suggests it would at least be possible.
- iptel 2y ago
  Absolutely, when call hits local switch it can be terminated differently based on its location. Particularly pertinent for modem based services in the 90s. A single national dialup number would terminate on 100s of local pops and routing decisions would be done to keep traffic as local as possible.
  - timthorn 2y ago

grishka 2y ago

Now I'm curious about how this worked in my city where we most definitely didn't have anything digital to our phone system at the time. As in, you had to use pulse dialing, and sometimes, rarely, your calls would glitch such that you would hear someone else talking over your call. Yet I remember consistently getting 40-something kbit over that.

kragen 2y ago
LZW?

oldandboring 2y ago

I remember some ISPs allowing you to "shotgun" two 56k modems for double the speed! Like some other commentors I also fondly remember ISDN. Overall I found it to be finicky. Sometimes one channel would just drop, even if a phone call wasn't coming in. And, in order to use a traditional analog phone with your ISDN line, you needed a special powered "TA" adapter or the phone wouldn't ring when a call came in.

hackthemack 2y ago

I have to wonder if the cap (theoretical) on the copper wires was more because of the technology standards in play at the time. Surely the copper wires could have handled more if they did not have to carry voice communication (with the old tech specs of the time) any longer? Ok. Searched around. Here is an article that states old copper could have carried 1 gigabit. https://www.newscientist.com/article/2317040-ordinary-copper-telephone-wire-could-carry-gigabit-broadband-speeds/ https://www.newscientist.com/article/2317040-ordinary-copper...

mannyv 2y ago
They did it for efficiency. The observation was that the human voice doesn't use most of the audio spectrum, so they optimized everything for voice. A reasonable decision at the time.
quink 2y ago
Of course ancient telephone wiring can carry 1 Gbps. The real question you always, always, always, need to be asking yourself is: Over what distance? Make that distance short enough, as has happened with FTTN, or FTTC deployments in a whole heap of places, you're basically building a network that's, and I'll keep this very brief, subpar. Since you mentioned a UK context there, Openreach rolled out an upgrade that kept the last mile of copper but now just about a decade later they're rolling out Full fibre. Whatever argument copper had, it went out the window near enough a decade ago.
- quink 2y ago
  OK, had a look through the linked paper. The big graphs, on page 8, tell you that if you decrease the twist length - which would entail relaying all the copper in the entire network, at which point you may as well put down fibre instead - you will get -20 dB at 10 GHz over a distance of 0.5m, 50cm, less than two feet, instead of -25 dB in the worst case. In other words, instead of losing 99.7% of the signal over that distance, it'll only lose 99% of the signal. Sure, it helps, but consider me underwhelmed.
  - 2y ago

Synaesthesia 2y ago

I could tell what connection speed my modem was going to be by the sound of the handshake. There were distinct sounds for all the different modes. I remember us getting our first modeum, it was 800 baud! Then we moved to 2400, 14.4, 33.6 and eventually all the way to 56k.

bryanlarsen 2y ago
800 baud? Do you mean 300 baud? 800 baud is not a standard speed so if they did exist you'd have to supply both ends of the connection..
- Synaesthesia 2y ago
  Oh yeah it was 300!
  - bryanlarsen 2y ago
    Darn, I was hoping it was some sort of oddball thing. Those are always interesting.

timewizard 2y ago

> Using the Digital Signal 0 (DS0) encoding DS0 is not encoding. It's (pseudo) framing. > phone calls became digital with The G.711 encoding in either aLaw or muLaw format.

pimlottc 2y ago

To be clear, this was well known at the time. It was advertised that 56k was for download only and required an ISP that supported it. For those living in rural areas, there often weren’t any local options (long distance was certainly not free in those days). But for those who could get it, it was definitely a big improvement.

kreddor 2y ago

TIL why upload on 56k modems were capped on 33.6k. I always wondered about that. Super interesting stuff! I also remember back in the day that my 56k modem would often only connect at like 48k or so, especially when it was raining. I guess living far out from the city made the connection more noisy?

aa-jv 2y ago

I had made a small career on building Internet Service Providers in California, in the early days, and will never forget how liberating it was to carry my laptop to the Griffith Park observatory with a fully-charged Ricochet modem plugged in, communicating to my house down in Los Feliz, where another Ricochet modem gateway'ed me to the Internet via the house 56k line .. It was truly astonishing to be up there, checking email. A few, what seems very short, years later .. and now it is just normal.

DonHopkins 2y ago

There was a time when 300 and 1200 baud modems cost about $1/baud.

exabrial 2y ago

Man I wish we still had slow connections, given all the dumb crap on webpages these days. Was crazy to think about trying to get your page to load in less than 64k a few years back.

msarrel 2y ago

Yes, and I provisioned them. You could shotgun them. Fun times

deleted 2y ago

[deleted]

sgarland 2y ago

I remember the day we got 56K from our ISP. Our modem was 56K (no idea what model, some internal WinModem), but the ISP was limited to 33.6K. Then one day, the connection screech sounded different, and I excitedly pointed this out. Several seconds later, it connected, and lo and behold, we had 66% faster downloads. The fact that all of this worked continues to amaze me, but then, so do mobile phones. I understand at a high level how CDMA works, but it’s just so insane…