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Comment by gerdesj | Hacker News Reader

"where we might as well save the bandwidth"

I come from a world (yesteryear) where a computer had 1KB of RAM (ZX80). I've used links with modems rocking 1200 bps (1200 bits per second). I recall US Robotics modems getting to speeds of 56K - well that was mostly a fib worse than MS doing QA these days. Ooh I could chat with some bloke from Novell on Compuserve.

In 1994ish I was asked to look into this fancy new world wide web thing on the internet. I was working at a UK military college as an IT bod, I was 24. I had a Windows 3.1 PC. I telnetted into a local VAX, then onto the X25 PAD. I used JANET to get to somewhere in the US (NIST) and from there to Switzerland to where this www thing started off. I was using telnet and WAIS and Gopher and then I was apparently using something called "www".

I described this www thing as "a bit wank", which shows what a visionary I am!

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Fellow old here, I had several 56k baud modems but even my USR (the best of the bunch) never got more than half way to 56k throughput. Took forever to download shit over BBS...

> several 56k baud modems

These were almost definitely 8k baud.

In case anyone else is curious, since this is something I was always confused about until I looked it up just now:

"Baud rate" refers to the symbol rate, that is the number of pulses of the analog signal per second. A signal that has two voltage states can convey two bits of information per symbol.

"Bit rate" refers to the amount of digital data conveyed. If there are two states per symbol, then the baud rate and bit rate are equivalent. 56K modems used 7 bits per symbol, so the bit rate was 7x the baud rate.

Yes, except that in modern infra i.e. WiFi 6 is 1024-QAM, which is to say there are 1024 states per symbol, so you can transfer up to 10bits per symbol.

Not sure about your last point but in serial comms there are start and stop bits and sometimes parity. We generally used 8 data bits with no parity so in effect there are 10 bits per character including the stop and start bits. That pretty much matched up with file transfer speeds achieved using one of the good protocols that used sliding windows to remove latency. To calculate expected speed just divide baud by 10 to covert from bits per second to characters per second then there is a little efficiency loss due to protocol overhead. This is direct without modems once you introduce those the speed could be variable.

Yes, because at that time, a modem didn't actually talk to a modem over a switched analog line. Instead, line cards digitized the analog phone signal, the digital stream was then routed through the telecom network, and the converted back to analog. So the analog path was actually two short segments. The line cards digitized at 8kHz (enough for 4kHz analog bandwidth), using a logarithmic mapping (u-law? a-law?), and they managed to get 7 bits reliably through the two conversions.

ISDN essentially moved that line card into the consumer's phone. So ISDN "modems" talked directly digital, and got to 64kbit/s.

56k relied on the TX modem to be digitally wired to the DAC that fed the analog segment of the line.

An ISDN BRI (basic copper) actually had 2 64kbps b channels, for pots dialup as an ISP you typically had a PRI with 23 b, and 1 d channel.

56k only allowed one ad/da from provider to customer.

When I was troubleshooting clients, the problem was almost always on the customer side of the demarc with old two line or insane star junctions being the primary source.

You didn’t even get 33k on analog switches, but at least US West and GTE had isdn capable switches backed by at least DS# by the time the commercial internet took off. Lata tariffs in the US killed BRIs for the most part.

T1 CAS was still around but in channel CID etc… didn’t really work for their needs.

33.6k still depended on DS# backhaul, but you could be pots on both sides, 56k depended on only one analog conversion.

Yeah I got baud and bit rates confused. I also don't recall any hayes commands anymore either...

Confusing baud and bit rates is consistent with actually being there, though.

As someone that started with 300/300 and went via 1200/75 to 9600 etc - I don't believe conflating signalling changes with bps is an indication of physical or temporal proximity.

I think it was a joke implying you'd be old enough to forget because of age, which in my case is definitely true...

No, just that confusing the two was ubiquitous at the time 14.4k, 28k, and 56k modems were the standard.

Like it was more common than confusing Kbps and KBps.

I mean, the 3.5" floppy disk could store 1.44 MB... and by that people meant the capacity was 1,474,560 bytes = 1.44 * 1024 * 1000. Accuracy and consistency in terminology has never been particularly important to marketing and advertising, except marketing and advertising is exactly where most laypersons first learn technical terms.

I started out with a 2400 baud US Robotics modem with my "ISP" being my local university to surf gopher and BBS. When both baud rates and bits per second were being marketed side by side I kinda lost the thread tbh. Using different bases for storage vs transmission rates didn't help.

Oh, I got the implication, but I think it was such a common mistake back then, that I don't think it's age-related now - it's a bit of a trope, to assume baud and bps mean the same thing, and people tend to prefer to use a more technical term even when it's not fully understood. Hence we are where we are with terms like decimate, myriad, nubile, detox etc, forcefully redefined by common (mis)usage. I need a cup of tea, clearly.

Anyway, I didn't think my throw-away comment would engender such a large response. I guess we're not the only olds around here!

The real analog copper lines were kind of limited to approx 28K - more or less the nyquist limit. However, the lines at the time were increasingly replaced with digital 64Kbit lines that sampled the analog tone. So, the 56k standard aligned itself to the actual sample times, and that allowed it to reach a 56k bps rate (some time/error tolerance still eats away at your bandwidth)

If you never got more than 24-28k, you likely still had an analog line.

Yeah 28k sounds more closer to what I got when things were going well. I also forget if they were tracking in lower case 'k' (x1000) or upper case 'K' (x1024) units/s which obviously has an effect as well.

Line speed is always base 10. I think everything except RAM (memory, caches etc.) is base 10 really.

The lower case "k" vs upper case "K" is an abomination. The official notation is lower case "k" for 1000 and lower case "ki" for 1024. It's an abomination too, but it's the correct abomination.

That's a newer representation, mostly because storage companies always (mis)represented their storage... I don't think any ISPs really misrepresent k/K in kilo bits/bytes

56k was also unidirectional, you had to have special hardware on the other side to send at 56k downstream. The upstream was 33.6kbps I think, and that was in ideal conditions.

The special hardware was actually just a DSP at the ISP end. The big difference was before 56k modems, we had multiple analog lines coming into the ISP. We had to upgrade to digital service (DS1 or ISDN PRI) and break out the 64k digital channels to separate DSPs.

The economical way to do that was integrated RAS systems like the Livingston Portmaster, Cisco 5x00 seriers, or Ascend Max. Those would take the aggregated digital line, break out the channels, hold multiple DSPs on multiple boards, and have an Ethernet (or sometimes another DS1 or DS3 for more direct uplink) with all those parts communicating inside the same chassis. In theory, though, you could break out the line in one piece of hardware and then have a bunch of firmware modems.

The asymmetry of 56k standards was 2:1, so if you got a 56k6 link (the best you could get in theory IIRC) your upload rate would be ~28k3. In my expereience the best you would get in real world use was ~48k (so 48kbpd down, 24kbps up), and 42k (so 21k up) was the most I could guarantee would be stable (baring in mind “unstable” meant the link might completely drop randomly, not that there would be a blip here-or-there and all would be well again PDQ afterwards) for a significant length of time.

To get 33k6 up (or even just 28k8 - some ISPs had banks of modems that supported one the 56k6 standards but would not support more than 28k8 symmetric) you needed to force your modem to connect using the older symmetric standards.

* 56k baud modems but even my USR (the best of the bunch) never got more than half way to 56k throughput*

56k modem standards were asymmetric, the upload rate being half that of the download. In my experience (UK based, calling UK ISPs) 42kbps was usually what I saw, though 46 or even 48k was stable¹ for a while sometimes.

But 42k down was 21k up, so if I was planning to upload anything much I'd set my modem to pretend it as a 36k6 unit: that was more stable and up to that speed things were symmetric (so I got 36k6 up as well as down, better than 24k/23k/21k). I could reliably get a 36k6 link, and it would generally stay up as long as I needed it to.

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[1] sometimes a 48k link would last many minutes then die randomly, forcing my modem to hold back to 42k resulted in much more stable connections

Even then, it required specialized hardware on the ISP side to connect above 33.6kbps at all, and almost never reliably so. I remember telling most of my friends just to get/stick with the 33.6k options. Especially considering the overhead a lot of those higher modems took, most of which were "winmodems" that used a fair amount of CPU overhead insstead of an actual COM/Serial port. It was kind of wild.

Yep. Though I found 42k reliable and a useful boost over 36k6 (14%) if I was planning on downloading something big¹. If you had a 56k capable modem and had a less than ideal line, it was important to force it to 36k6 because failure to connect using the enhanced protocol would usually result in fallback all the way to 28k8 (assuming, of course, that your line wasn't too noisy for even 36k6 to be stable).

I always avoided WinModems, in part because I used Linux a lot, and recommended friends/family do the same. “but it was cheaper!” was a regular refrain when one didn't work well, and I pulled out the good ol' “I told you so”.

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[1] Big by the standards of the day, not today!

> I've used links with modems rocking 1200 bps

Yo, 300 baud, checking in.

Do I hear 110?

+++ATH0

Ah, the good old days. I remember dialing up local BBSes with QMODEM.

AT&C1&D2S36=7DT*70,,,5551212

PoiZoN BBS Sysop chiming in. I ran the BBS on a free phone line I found in my childhood bedroom. I alerted the phone company and a tech spent a day trying to untangle it, but gave up at the end of his shift. He even stopped by to tell me it wouldn’t be fixed.

I didn’t know the phone number, so I bought a Caller ID box, hooked it to my home line, and phoned home. It wasn’t long before every BBS in town had a listing for it.

Man that tech was cool and did you a solid.

Many techs went to work for the phone companies for a reason.

That's awesome.

I had to wait til I was old enough to get a phone line in my own name before running a BBS. And also til I had a modem that would auto-answer, which was not a given back then!

But I confess my first question for a working but unassigned phone line would be: who gets the bill for long distance calls?

I had access to no-cost long distance calling through other administrative oversights, but they were a bit more effort to maintain! :)

Ha, same! On a TRS-80 Color, nonetheless. But I think I used four times, because no one else in the country had a BBS at the time (small city in Latin America).

It took a couple of years until it would catch on, and by then 1200 and 2400 bps were already the norm - thankfully!

My first modem (from 1987) was 300 baud, but it could be used in a split mode called 75/1200.

Before that I used 50 baud systems in the military as well as civil telex systems.

Mine was 300 baud, probably 1982?

And I felt privileged because the configuration for my TI-99/4A Terminal Emulator (which I believe was called Terminal Emulator) had options for 110 or 300 baud, and I felt lucky to be able to use the "fast" one. :)

My first modem (you always remember your first) had no carrier detection (and no Hayes commands, and no speaker...), so I would dial the number manually, then flip a switch when I heard the remote end pick up and send carrier to get the synchronization started.

It was incredibly exciting at the time.

Same year, I tried this cool new "Mosaic" software and thought it was a cool proof of concept, but there was no way this web thing could ever displace gopher

Which was right, today gopher has more users than ever! :)

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