A Brief History of Modems 249
Ant points out this two-page TechRadar article about the history of modems; the photographs of some behemoth old modems might give you new respect for just how much is packed into modern wireless devices.
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A Brief History of Modems
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UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things. -- Doug Gwyn
Re:Let me be the first to say (Score:2, Informative)
+++ATH0
Acoustic coupler era and POTS! (Score:5, Informative)
There are still a few of us left who grew up in the acoustic coupler era, where modems connected to the (back then standardized) handset, and really whistled and purred into the microphone.
Speeds? We started with 110 baud (which back then was equivalent to bits-per-second, if you subtracted stop bits). Then came 300 baud.
Then someone had an epiphany, and figured out that no-one could possibly type faster than 75 characters per second, and even if they could, the printer(!) that spit out whatever you typed wouldn't be able to. So by reserving the low frequencies for upstream data and the high frequencies for downstream, you could achieve the blazing speed of 1200 baud down and 75 baud up. The 1200/75 modem was a workhorse for a long time, with way faster downloads than 300/300 could give.
Then came 1200/1200, 2400/2400, 4800 (which was really 2400 with compression), 9600, and then the Trailblazer, which was running at a ridiculously low baud rate (100 baud IIRC), but at so many parallel channels that it achieved ~18000 bps aggregate. That was lightning fast! Imagine almost 2 kB/s (unless something moved the other way at the same time, in which case speeds of course would drop). The ASCII porn didn't stand a chance against that speed monster!
Then came the short-lived 38400, and finally the ubiquitous 56k modem. Yawn.
In the mid-90s, we got BRI (ISDN, 2*64 kbps in most of the world, 2*56 kbps in the US). Which pretty much ended the modem era, except for in the US and UK, where 56 kbps POTS modems reigned supreme until well after the millennium.
As a child of the 80s... (Score:5, Informative)
The biggest problem with using modems was that you had to let everyone in the house know you were on the "modem". This meant, sticking post-it notes to every phone in the house, so that someone would tell you they needed to use the phone rather than just picking up the phone and dialing. You also couldn't tie up the phone for hours on end. There was very very few people that had an answering service (not an answering machine), like most do today with VOIP or CableCompany Provided Voice.
You also had to remember, if you were one of those people that had it, disable call waiting, as many modems would drop the connection when a call waiting signal came through. I believe you had to add a *70 after the AT.. so you had something like:
Today people can spend all day actively or passively (by leaving the computer on) online. Wit
Rubbish (Score:4, Informative)
This should be the brief history of the personal PC modem.
There was no mention of the tons of ISDN modems used until the late 90s.
No mention of Codex or Pairgain devices. We had 64kbps, leased-line Codex modems humming along until, well, even today you'll find an odd one laying around. And T-1 Pairgains (not technically models) are still the best way to service outlying buildings on most campuses.
I understand that not every article can be complete. But you really can't talk about the history of modems without Pairgain (now ADC) and Codex.
Re:What!? No mention of AppleCat? (Score:3, Informative)
Just reading http://en.wikipedia.org/wiki/Novation_CAT [wikipedia.org]
Neat use of transfer bandwidth ideas
Re:Acoustic coupler era and POTS! (Score:5, Informative)
No, in the US T1 system, each B channel is 56 kbps, due to the entire T1 using inband signalling through bit-robbing (see above referenced article), and not out-of-band signalling as in the E1 system used elsewhere. At least that was the case back when ISDN became popular in the early-to-mid 90s.
The 16 kbps data channel for each B pair is independent of this.
T1 PRI = 23 * 56 kbps DS0 (+ 16 kbps), US BRI = 2 * 56 kbps (+ 16 kbps)
E1 PRI = 23 * 64 kbps DS0 (+ 16 kbps), EU BRI = 2 * 64 kbps (+ 16 kbps)
Re:Acoustic coupler era and POTS! (Score:3, Informative)
Again, you're confusing things. Actually confusing a couple things:
First:
T1 != ISDN. The only time you got 56kbps on a B channel was when you were calling out of your exchange in an environment that still used RBS.
Second, in the US:
A PRI is 23B (64kbps) + 1 D (64kbps) and all the signaling happened on the D channel or 24B (2nd-nth PRI)
A BRI is 2B (64kbps) + 1 D (16kbps) and all the signaling happened on the D channel.
Thirdly, in Europe:
A PRI is 30B (64kbps) + 1 D (64kbps)
Fourthly:
There is not a D channel per 'B pair' there is just a D channel.
If Wikipedia says something different it's, uhh, wrong. (But I think you're just misinterpreting it)
Re:US Robotics (Score:3, Informative)
I did my second incarnation of BBSing using a Datarace modem. It would only do 4800 when connected to other modems, but it would do 9600 if connected to another Datarace modem, but it did that by using up all of the voice bandwidth at once by going half-duplex over the line. I only found one other board that had a Datarace modem, but it shocked me the first time I saw "CONNECT 9600" when I was used to "CONNECT 4800".
Re:As a child of the 80s... (Score:4, Informative)
Pft, 5 years? 12 months? Just over two months here. I'm far enough away from any sort of digital lines that I've got to use a wireless line of sight service, and due to geography, they couldn't get a receiver installed for me until late October. By the end, I was desperate enough to have a second phone line and a Linux box running 24/7 to keep a connection established and fed into my router, which the other computers in the house connected to.
You're right about modems being cheap in the wrong way these days. All the modems I have hanging around here are several years old. Unfortunately, I only have so-called "winmodems", but it's been awfully nice of Dell to ship Linuxant [linuxant.com] drivers for their Linux laptops, the binary modules of which can be used to replace the pared-down, feature limited ones included in the so-called "open" Linuxant packages.
--- Mr. DOS
Re:Baud vs bps (Score:5, Informative)
The American Heritage Dictionary of the English Language, Fourth Edition says, "acronym n. A word formed from the initial letters of a name, such as WAC for Women's Army Corps, or by combining initial letters or parts of a series of words, such as radar for radio detecting and ranging."
MOdulation/DEModulation certainly seems like it qualifies to me. It is using the initial parts of a series of words. I don't see how it is any different than RAdio Detecting And Ranging.
Re:Let me be the first to say (Score:5, Informative)
You mean:
+++
[pause*]
ATH0
ATDT18400MODITUP
[*: Pause required for modems properly requiring a delay before dropping to data mode, as patented by Hayes. Other, non-supporting/paying modems used the same commands, but did not require silence between +++ and a command: A properly-crafted ping command was sufficient to take such modems/users completely neatly offline in an age of TCP/IP, though a link for a citation evades me in these modern times.]
Re:Let me be the first to say (Score:3, Informative)
It's documented in CVE-1999-1228 [nist.gov] but I'm sure it's much older than that.
BBS Documentary! (Score:3, Informative)
I was online with many BBS' with during dial-up modems days before they died because of the Internet. /. [slashdot.org] has a few old stories about this awesome documentary from years ago:
Google Video [google.com] has all the parts online:
1 [google.com]: Baud introduces the story of the beginning of the BBS, including interviews with Ward Christensen and Randy Suess, who used a snowstorm as an inspiration to change the world.
2 [google.com]: Sysops and Users introduces the stories of the people who used BBSes, and lets them tell their own stories of living in this new world.
3 [google.com]: Make it Pay covers the BBS industry that rose in the 1980's and grew to fantastic heights before disappearing almost overnight.
4 [google.com]: Fidonet covers the largest volunteer-run computer network in history, and the people who made it a joy and a political nightmare.
5 [google.com]: Artscene tells the rarely-heard history of the ANSI Art Scene that thrived in the BBS world, where art was currency and battles waged over nothing more than pure talent.
6 [google.com]: HPAC (Hacking Phreaking Anarchy Cracking) hears from some of the users of "underground" BBSes and their unique view of the world of information and computers.
7 [google.com]: Compression tells the story of the PKWARE/SEA legal battle of the late 1980s and how a fight that broke out over something as simple as data compression resulted in waylaid lives and lost opportunity.
8 [google.com]: No Carrier wishes a fond farewell to the dial-up BBS and its integration into the Internet.
There is a DVD version that can be ordered [bbsdocumentary.com], or downloaded for free and legally [bbsdocumentary.com] (hurray for Creative Commons [creativecommons.org]) with less contents.