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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I tell them to turn to the study of mathematics, for it is only there that they might escape the lusts of the flesh. -- Thomas Mann, "The Magic Mountain"
Let me be the first to say (Score:5, Funny)
Re:Let me be the first to say (Score:5, Funny)
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+++ATH0
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.]
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It's documented in CVE-1999-1228 [nist.gov] but I'm sure it's much older than that.
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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.
Re:Acoustic coupler era and POTS! (Score:5, Insightful)
Sadly, your comment contains more actual information, and is better written, than the 'article.'
Re:Acoustic coupler era and POTS! (Score:5, Funny)
Sadly, your comment contains more actual information, and is better written, than the 'article.'
You read the articles?
Re:Acoustic coupler era and POTS! (Score:5, Funny)
ahh sh*t, busted.
Re:Acoustic coupler era and POTS! (Score:5, Funny)
Sadly, your comment contains more actual information, and is better written, than the 'article.'
You read the articles?
Only in Playboy
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Unfortunately, my comment isn't all that great, due to too much Innis & Gunn. There's a horrific typo in it; 75 cps should be 7.5 (given single parity and stop bits).
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>>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.
Really? I assumed that by the late 90s, the US had transitioned to 8-bit sampling. I mean, DS-0 in the US has been 64kbps (8-bit samples * 8000 samples per second) since, what, the 50s?
Re:Acoustic coupler era and POTS! (Score:5, Interesting)
Yeah, US ISDN speeds really were (are?) lower, due to RBS compensating for bad signal quality.
See here [wikipedia.org] for details.
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)
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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
Re:Acoustic coupler era and POTS! (Score:4, Interesting)
If you have multiple PRIs, you can run NFAS (Non-facility associated signalling). You run 24B+0D on all but a handful of circuits, 23B+1D on those. The D channel carries enough signalling for call setup & tear down on all the PRIs in the NFAS group. That way, you're gaining an extra B channel per circuit.
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The figure of 56 kbit/s is derived from its implementation using the same digital infrastructure used since the 1960s for digital telephony in the PSTN, which uses a PCM sampling rate of 8,000 Hz used with 8-bit sample encoding to encode analogue signals into a digital stream of 64,000 bit/s. However, in the T-carrier systems used in the U.S. and Canada, a technique called bit-robbing uses, in every sixth frame, the least significant bit in the time slot associated with the voice channel for
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My understanding is that only applies to a single DS-0 inside the frame or superframe. I think it's channels 0 and 12 for a standard T-1.
In any event, 2B+D has an additional, out of band, signaling channel to cover this.
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It does? 2 (B)earer channels for data and the (D) channel is X.25 packet and call set up & tear down. There's no "out of band".
Re:Acoustic coupler era and POTS! (Score:5, Interesting)
Heck, I was using "56K" dialup until earlier this year. Even though it was 33,600. For most things I was doing, it was plenty fast enough. Only thing that killed it was OS X software updates, and the occasional twit who forgot that email is a *text* medium.
Brett
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No kidding! You could even download respectably sized files.... just no instant gratification.
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baud to bps included the stop bits etc, modems simply changed freqs to match the 1's and 0's. I think there is still an acoustic coupled modem in my cupboard, next to my IBM XT. The big shift was from FSK to QAM, then the bps really started to climb.
Re:Acoustic coupler era and POTS! (Score:5, Interesting)
One of the better innovations with modems, but one that was not heralded much was MNP3. MNP5 is a superset and offered compression which helped things, but MNP3 dealt away with the aggravation of line noise, and this by itself made a lot of difference in file transfers.
ISDN did dent modem sales, but at the time in the mid 1990s, ISDN was fairly expensive (about $150-$300 a month.) However, it had the advantage of very low latency. Modems (and mom/pop ISPs) really didn't die off until cable and DSL connections became both widespread and decently inexpensive.
Ironically in the US, modems have not been driven away completely. There are still plenty of areas that do not have cable or DSL access. Sometimes using a cellular "modem" [1] provides a solution, but sometimes that doesn't work (especially in hilly areas). Also, some people just don't do much with broadband, so they have downgraded to dialup because it is cheap.
[1]: Technically it isn't a modem, but a CSU/DSU. However, most people call the USB devices that plug into a laptop modems, even though they do no analog modulation or demodulation.
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Re:Acoustic coupler era and POTS! (Score:5, Interesting)
Ahh, and not only exciting, but would only later be known as 'epic'. My first foray into the internet was on our school library's VT100 terminals which were primarily used for queuing up inter-library loan requests. This was in 1995. Getting Mortal Kombat cheat codes and fatalities was never so easy. I also remember printing off the Duke Nukem 3D build editor docs on that same machine, but I think that was a bit later on. Shortly after my church confirmation class took a trip to a ''church'' college which had machines which displayed the WWW in all its graphical glory. They were running Netscape (probably 2.0 or 3.0, I didn't bother to check at the time). I was smitten. Not long after that, our town got local dialup access, and at age 15 I convinced my mom to let me pay for and install a second phone line for it. I soon learned enough HTML and Javascript to 'hack' the Perl/CGI chat room I used to fool around in -- giving myself full administrative ability. W00t! The coolest damned thing I ever did was play my chatroom buddy in Quake II -- ON THE INTERNET!
To this day, there is nothing more exciting than hearing that 14.4 modem chirp off the connection sequence. Sometimes I kinda wish my DSL connection made that same noise. I'll always treasure those halcyon days. Thank you, Mr. modem inventors. Mine served me well far longer than it should have, mostly reliably, and is the singlemost important reason I ever became a computer geek. Thanks a million! Now who is calling me at five in the morn--
-AT++[NO CARRIER]
Re:Acoustic coupler era and POTS! (Score:4, Interesting)
n 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.
When the U.S operating companies started rolling out ISDN, I thought all my connection issues were history. But OCs still thought of themselves as regulated monopolies (they still do, really) and got the FCC to set high per-minute rates for ISDN usage — which pretty much destroyed any chance of ISDN being widely adopted. So we were stuck with the damn modems until DSL allowed us to sidestep the federal tariffs. And we still haven't caught up.
I might be misremembering, but I'm pretty sure that US ISDN also had 64 kbps data ports. The 56 kbps limit was imposed on modems because the FCC experts thought that analog connections needed a safety margin to prevent crosstalk.
Re:Acoustic coupler era and POTS! (Score:5, Interesting)
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Re:Acoustic coupler era and POTS! (Score:5, Interesting)
I must be getting old. I still think in terms of, "acoustic couplers... 6502's... that was a few years ago." Doesn't seem that long ago really. Now maybe most people reading this weren't *born* yet at the time.
Soon enough though folks like us will die off, and there will be a generation which has always been connected - nonstop, rather than having to dial things up, doesn't remember the mainframe days, and thinks a 386 is an old CPU. I suppose it's the way of things. Doesn't make me feel any younger though! But what certainly seems true is that a much lower percentage of people now know the nuts and bolts of how things work. I attribute this to several things:
(1) It's harder to *get at* the nuts an bolts now- there are far more layers of abstraction in the way.
(2) Back in the 70's and much of the 80's, home computers were owned by hobbyists, not Joe Sixpack, so most people involved were inclined towards curiosity about how shit worked. Now there still some - more on an absolute scale, but fewer percentage wise.
(3) Now it's possible to use a computer without knowing anything theoretical. Back then, it was not, so it was required that people were technical.
It's not a bad thing generally, and I'm glad so much of humanity is now connected, but there *was* something lost as well (Eternal September, loss of the original net culture, spam, widespread abuse of various protocols, a trend towards a computing monoculture...).
Re:Acoustic coupler era and POTS! (Score:5, Interesting)
For that matter, I guess it's more than just technology. Almost none of the kids graduating with my nephew know how to fix a leaking faucet, grow a tomato, or change the oil in their car. Hell, two thirds of them can't even cook rice.
I can't help but feel that we've lost something valuable.
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And 33.6. I had a 33.6 modem and I swear it provided better latency than any 56k modem I used afterwards. The other thing I hated about 56k modems is that they were only 56k down, not up; a 33.6 could do 33.6 bi-directional whereas a 56k could do 56k down or 28.8k bidirectional, or something like that. All I know is uploading anything significant on a 56k would kill download speed. My 33.6 was much more consistent, even if it couldn't achieve the hallowed 7kBps download.
Oh yeah, there was also the whole
Brings back memories (Score:5, Interesting)
I have mod points to burn but I have to post in here.
The traffic system I worked on had 300 baud modems attached to cheap leased lines (soldered in, mostly). Two modems per card. 8 cards on a bytecraft backplane. Up to 128 modems on a 19 inch rack. Each modem had three LEDs (carrier, TX, RX) and at the speed the system operated you could see the poll/response from the regional controller to the sites and back. In the dark it was a thing of beauty. Computers of old.
If something was wrong in the logic (say a checksum mismatch) then you could see it in the LEDs because one channel (slot) would not follow the nice pulse sequence. Several times I mucked up the checksums of a rack and took out a lot of sites. Maybe I shouldn't post about that...
Going back in time my 6502 system had a modem for the cassette interface. I knew you could overclock the UART and FSK modem driver and I had dreams of using my uncles reel to reel hifi system for storage. Never happened. Though I did find that you could use the cassette player as a sound card of sorts by locking on REC and PLAY.
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The traffic system I worked on had 300 baud modems attached to cheap leased lines
Trunked radio systems still communicate between radio sites and the central node using 1200 baud AFSK on four-wire leased lines. They're not cheap, though. You can tell how busy and how healthy a system is by the pattern of blinks on the TX/RX lights...
Lady, there ain't nothin' so complicated... (Score:5, Interesting)
In "The African Queen," Katherine Hepburn's character asks Humphrey Bogart's character to make a torpedo. Bogart's character says something to the effect that "Lady, there ain't nothing so complicated as the inside of a torpedo. It's got gyroscopes, compressed air chambers, compensating cylinders..."
I remember once reading details about just how the signals in a 1200 bps modem worked... and modems at higher rates. It was just jaw-dropping how sophisticated it was. The reason why there was a distinction between "bps" and "baud" is that "baud" refers to the number of times per second the signal changes. Well, a 1200 bps modem only changes its signal 600 times a second... but it uses four different combinations of frequency and phase, so each signal combination signals two bits. That's bad enough, but the combinations literally increase exponentially. The 9600 bps modem actually requires the receiver to sense and distinguish sixteen different analog combinations (so that it can encode four bits at a time).
At the time I figured they had to be close to the theoretical limit, which depends on the bandwidth and the noise level. A phone line is only good up to about 3000 Hz. so the 2400 baud rate of a 9600 bps modem is changing about as fast as it can. The rest depends on how noisy the line is.
Theoretically, of course, you can signal at an infinite rate on a perfectly noise-free channel. Just send 3.141592653 volts on the end and measure it with a ten-digit digital voltmeter and, voila! You're sending ten digits at once. Except there aren't any ten-digit voltmeters.
I was frankly flabbergasted when they managed to cram 56 kilobits per second into a phone line. Of course, the 56 kb modems never really ran at that speed--they were always falling back to lower speeds because the phone lines were too noisy. Then they added compression, which didn't do much good because the ZIP files and JPGs you were sending were already compressed. In reality they were trying to cram 56 kilobits of data into a 33 kilobit bag, but it was amazing that it even worked some of the time.
But, lady, there ain't nothin' so complicated as the inside of a modem.
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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
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Yeah I think the fact that ADSL, cable and 3G are always on is more important than the throughput. It makes it possible to plan to check something online from a single source, rather than grabbing information in advance and creating multiple copies.
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It could be pretty much a disaster if you were playing an online game (Moria/Angbang etc) for quite a while (months) and if someone picked up the phone and you were disconnected, the BBS marked your character as dead. You had to message, I mean beg, the sysop to restore your character...
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Yeah I think the fact that ADSL, cable and 3G are always on is more important than the throughput.
Not with Verizon 3G.... can't talk and surf at the same time on CDMA. A fact that AT&T is hammering home on their ads right now.
Not as annoying as the old analog modem situation, but still an issue, especially if you tether your phone.
Re:As a child of the 80s... (Score:5, Insightful)
I was using dialup as little as 5 years ago. I was too far from the exchange for ADSL and ISDN was too expensive. Then Telstra introduced a plan where you paid about $100/month for BRI ISDN, giving you 2 64K channels. So I could be surfing at 128K unless someone wanted to use the phone in which case it would drop back to 64K. Better than my 33K modem! I assume Telstra did that to get one last little bit of life out of the ISDN infrastructure that nobody wanted anymore. They took that option away a few years ago, but fortunately I'm on ADSL now.
My mum was using dialup as little as 12 months ago, until she got her two-way satellite connection. I find that the quality of modems these days is pretty awful. The people in Australia who use them typically use them because they are too far away from the exchange to get anything else, which means the signals are travelling over copper that could be decades old. You need a good modem which can adjust its impedance settings and keep tuning to the line characteristics for that to work at reasonable speeds.
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
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I believe you had to add a *70 after the AT
It depends on your telephone company. If you have Touch Tone, you usually have to use *70 or #70. If you still have pulse dialing, you have to use 1170.
The commas are also important. Each comma adds a two-second pause (unless that's been modified in the modem's registers). Placing a comma or two after the *70 gives the telephone company time to give you a dial tone again so the phone number digits aren't lost.
Re:As a child of the 80s... (Score:5, Funny)
Ah, smart. My solution was to just bellow really loudly that everyone should stay off the phone so I could use the modem. This was usually followed by my parents telling me to use the intercom instead of yelling, or telling me to stop tying up the phones, or asking if I'd done my homework yet.
You also couldn't tie up the phone for hours on end. There was very very few people that had an answering service
No way man. The call-waiting thing was, to me, a feature. It meant that I could assure my parents that I wouldn't be tying up the phone lines and preventing people from calling. It was an enormous hassle when the thing disconnected but it meant my parents couldn't use that as an excuse to tell me not to use it.
When I was 14 or so my parents felt comfortable enough to leave me home alone for four days when they went out of town. Still, they asked my uncle to check up on me periodically. Of course, since I didn't care about missing calls, I fired up the modem, logged on, and kept the call-waiting disabled. This meant that my uncle got a busy signal for a day and a half when he was trying to call to see how I was doing, until he finally drove over to see if I was just tying up the line with the modem, or if I was dead on the floor after a brutal break-in that knocked the phone off the hook.
Pointless nostalgia now concluded. More pointless nostalgia on this topic may be found here [mirrorshades.org] if anyone's interested.
Written by someone born in the 90s? (Score:5, Insightful)
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It was also expensive as hell. Although, if I recall correctly, someone with a sportster could dial your courier at 56k, while the reverse was not true (sportster didn't support receiving calls at 56k).
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You recall incorrectly. First of all, there can only be a single digital-to-analog conversion anywhere on the line for 56k to work, otherwise there's too much noise and you'll fall back to 33.6. The only way for 56k to work is if the ISP end is all digital - the signal comes in on a T1 line, and the modems are all digital. Secondly, 56k is only 56k downstream; uploading is still limited to 33.6 - so if you could connect two modems on a phone line that was clean enough for 56k to work, you couldn't downlo
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The upload speed is not inherently limited to 33.6k. In fact, the V.92 standard allows up to 48k upload speeds but that increase comes at the cost of reduced download speeds.
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I could never get 56k modems to retrain to 33.6, and 56k downloads always seemed to be hosed if any kind of uploading was necessary. So basically you had 56k (and due to line noise, frequently 48k instead) down or 28.8 down/up, but never 33.6 up.
My trusty old 33.6 did 33.6 up/down in its sleep, all day long if necessary. I think I actually played EQ phase 2 beta over that thing . . . oh the memories.
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There is one other algorithm that the Courier had that the Sportster lacked: the USR proprietary algorithm, HST. On some nights, you could have a 28.8 with this technology, and it could go up to 40kbps. This was pre-56k on uncompressed data, so it was a big YMMV type of thing. However back then, it was cool to be able to download something overnight. It beat running to the university campus's 24 hour computer lab with a boxful of floppies and a pkzip splitter.
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.
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Yep. The Codex 2264 was the shit. Until the 3260 came along. Still, if my life depended on a modem working and dealing with crappy lines and marginally compliant other parties I'd go with the 2264.
Honebrew (Score:2, Interesting)
It's sad that only commercial modems are mentioned.
I well remember building a series of homemade modems starting in the early '80s.
There were many magazine articles for homebrew modems. Most of these derived from the FSK radio modems in widespread use by Hams at the time.
The did have 1200 baud modems in the 1970s (Score:2)
The computer was a DECsystem10. It was difficult to keep up with the blinding speed of the text scrolling past on the screen!
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The computer was a DECsystem10
Do you recall the type of serial interface cards it used? Or was the modem connected to the console? The PDP 11/84s and 11/83s I used used variants of the DZ11 MUX card which gave eight channels. If still have the octal interrupt vector and bus address sequence imprinted on my brain:
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A DECsystem10 is a mainframe that does timesharing. I never saw the thing - it lived in the main school district office downtown.
We did have a PDP 11/34 in the school. It had a DZ11 card, but we never got it to timeshare BASIC while I was there. Then IBM changed the world two years later.
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I stuffed up. I was thinking PDP 10 where you wrote DECsystem10.
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Or you just mean the lack of a backspace key sucked... or?
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Baud vs bps (Score:4, Interesting)
No MODEM using the standards indicated has worked at any speed greater than 2400 baud. (That means 2400 transitions per second).
Many MODEMs work at 4800, 9600, 14400, 56000 bps (bits per second, or pieces of digital information per second).
What the MODEMs have done is use the ability to deliver multiple bits per such transition using FSK, QFSK,QAM, etc.
MODEMs at 2400baud or less did not require flow control -- they worked at serial line speed, and did not buffer. Modems at 4800bps and higher did buffering and would do various flow-control techniques.
Original MODEMs didn't start at 150baud, they started at 75baud, but lazy authors write lazy articles.
The acoustic-coupler worked great at 300baud (TI Silent 700), miserably at 600baud, and terribly at 1200baud.
Still this technology made itself obsolete. People were tying up VOICE channels on the PSTN switches and Telcos hated it, so they created DSL to take data off the voice channels.
E
P.S. The word MODEM (as the article indicates) represents MOdulatorDEModulator. Hence it should be capitalized. This is also try of enCOderDECoder (CODEC). Slightly less related yet as correct LASER and RADAR....
Re:Baud vs bps (Score:5, Insightful)
]P.S. The word MODEM (as the article indicates) represents MOdulatorDEModulator. Hence it should be capitalized. This is also try of enCOderDECoder (CODEC). Slightly less related yet as correct LASER and RADAR....
Generally when an acronym is pronounced as a single word and has entered general usage, it is not capitalized. These days scuba, laser, and radar are not capitalized. Nor is modem.
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:Baud vs bps (Score:5, Funny)
The word MODEM (as the article indicates) represents MOdulatorDEModulator. Hence it should be capitalized. This is also try of enCOderDECoder (CODEC). Slightly less related yet as correct LASER and RADAR....
Okay, okay, fair point, but ...
People were tying up VOICE channels
Come on, that one you just made up.
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That all depends on what you were trying to achieve. There certainly were modems that did flow control and buffering with speeds below 2400, however, it became more prevalent around that time because error correction, and data compression became wide spread. Most reputable manufac
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E (P.S. This has little to do with RS232. That's just the serial standard to communicate with the MODEM. The MODEM talked on the PSTN at the baud rates up to 2400baud).
A few things missing there (Score:3, Interesting)
Oh, for the "good old days" (Score:4, Insightful)
We all agreed that in a way, it is almost a shame that kids today are growing up with remarkably better technology than we had at their age (and it hasn't been that long ago that we were their age). We all sort of miss dealing with cobbled together and salvaged parts, trying to eek out any performance we could from our machines. One of the friends present recalled helping me overclock my 33 mhz machine to 36 mhz (woohooo! A 10% gain) and how excited we were.
These days, my cell phone has more computing power than the first three computers that I owned, and a much faster data transfer rate. The old technology still amuses me though.
Re: (Score:3, Interesting)
We all agreed that in a way, it is almost a shame that kids today are growing up with remarkably better technology than we had at their age (and it hasn't been that long ago that we were their age). We all sort of miss dealing with cobbled together and salvaged parts, trying to eek out any performance we could from our machines. One of the friends present recalled helping me overclock my 33 mhz machine to 36 mhz (woohooo! A 10% gain) and how excited we were.
Here's a fun factoid* for you: most electronic parts have an error tolerance of at least 1%, with 10% not unusual. Even things like the clock source of a PC would probably drift by about 0.1% due to things like humidity, temperature, or whatever. Or to put it another way, a modern 3GHz CPU running at a "fixed speed" loses or gains about 3MHz from the influence of the weather. Given that most modern CPUs do a lot more "work" per clock than old XT era processors, that means that just random variations in the
Yes, not "actually factual" (Score:2)
You're right about most of the components in a PC, but not what determines the clock stability. The clock speed is set by a phase-locked loop [wikipedia.org] using a crystal oscillator [wikipedia.org] (usually quartz) as a frequency reference. Quartz crystals used in your garden-variety PC typically have a worst-case environmental stability specification of 10 to 100 ppm (0.001% to 0.01%), depending on a lot of factors, most of which are design (and cost) parameters, and most of the time the clock frequency is much closer than that: R
US Robotics (Score:3, Interesting)
Re: (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".
For years, Hayes ended press releases with +++ATH0 (Score:5, Interesting)
Its a shame that the article missed so much....
Like the times when much of the industry didn't want to license the Hetherington Patent from Hayes on the "guard time" surrounding the "+++" in the escape sequence, so Hayes ended all of their press releases with +++ATH0 (which would cause a lot of modems to hang up on the BBS systems of their day).
They also missed the interesting fact that the "56K" modem was an old idea that was rattling around Bellcore for years before 1996 and fairly common knowledge in the Bell system. [The big issue with getting there was the need to have digital trunks connecting all of the dial-in server pools with the telephone network.]
Probable never would have become a mainstream consumer device without AOL. Until AOL, you really had to be a geek to use one.
And, of course, the modem wars of 1996-1998, as the major technology companies duked it out, the vast majority of modem companies went bust, including Hayes.
Re:For years, Hayes ended press releases with +++A (Score:5, Interesting)
This is how I remember it. Hayes modems, using the patent, required a certain amount of delay time surrounding "+++", their escape sequence, before the modem would recognize it. Thus, "+++" in the text stream wouldn't trigger it under normal circumstances because it would come and go too fast.
But the patent was a patent on the delay; and to avoid paying for the "delay" royalties, other modem companies would just use "+++" without the delay for their escape sequence, which risks modem confusion if accidentally sent as text, but otherwise wasn't that common. However, to embarrass non-patent modem companies, Hayes embedded "+++ATH0" in their digital documents. This would cause non-Hayes modems hang up if they ever transferred such documents. The trick sounds rather Microsoftian.
I remember other vendors complaining to the press, saying "you cannot patent pauses. Next they'll patent Ummm's" or something like that. (Obama would have a big bill if they did.)
Reminds me of my first Linux Job (Score:2)
Could you tell speed and error correction by ear? (Score:4, Interesting)
After thousands of times listening to my various modems connecting from 300bps to 56K and with the various incarnations of error correction I was eventually able to knowing how fast I was connected by sound alone. The problem was that as modems got faster and more sophisticated the connection time kept getting longer and longer. Sometimes I'd have to wait through 45 seconds or more of whistles, grinds and groans before the two modem would train. Ah, the good old days.
In the vain hope that they'll have nostalgia value someday I still have in my possession:
1) Mint condition Hayes Smartmodem 2400. The original workhorse.
2) Practical Peripherals 14.4K. long box with a one-line LCD that displays the connection speed and error correction mode
3) US Robotics 56K Courier - The last great standard.
Re: (Score:2)
Modems are hard to come by now (Score:3, Interesting)
I was trying to put together an inexpensive homebrew computer-to-transceiver audio interface for digital radio transmissions and needed a pair of audio frequency transformers. I knew that all POTS line modems had a transformer in them that would work and I thought that this would be a cheap source for parts that cost about ten bucks apiece new. Of course, I had just recently sent all my old modems to the recycler so I started asking around to see if anyone had a modem that they wanted to get rid of. Out of the more than 20 people I asked, not a single person still had one.
Hard to believe that only ten years ago the modem ruled supreme when it came to Internet access. Now you can't even find one to cannibalize.
KJ6BSO
Re: (Score:2)
Here in Melbourne, Australia computer swap meets (markets for grey marketing, mostly) usually have bins of old modems, mostly with their power supplies for two dollars each. If you buy two or three you can get a working unit. Are there similar markets where you live?
Re: (Score:2)
Are there similar markets where you live?
They used to be pretty common but not so much anymore. And I just wanted cannibalize them for a specific part--I wouldn't have even cared if the things worked as long as the 1:1 audio transformers weren't burnt out.
Re: (Score:2)
I have a couple of modems I could junk and I am sure a lot of people around here do to. Maybe put up a journal page and point your sig to it. You will have to pay postage. I could send you a few but its going to be from Australia, which could be expensive.
Re: (Score:2)
I could send you a few but its going to be from Australia, which could be expensive.
Yeah, it would undoubtedly be cheaper to drop the USD 20 on the new parts from Mouser, but thanks anyhow. I only brought it up to point out the current scarcity of modems.
Re: (Score:2)
Dude, you must not know how to use google...
You want a modem, you have but to only take out your credit card and go to US Robotics [usr.com] and purchase one to suit your needs from the about $250.00 to 19.95.
No mention of the Hayes VS. Telebit 14.4K wars?? (Score:3, Insightful)
Parkinson's Law (Score:4, Insightful)
While one might think things have improved by four orders of magnitude (10,000x), thanks to Parkinson's Law, they have only improved by two orders (100x). Navigating to the washingtonpost.com home page takes 7 seconds to load on my 2.5-year old 2GHz desktop with Firefox. CTRL-A and CTRL-C then paste into Notepad yields a 15K text file. 15 * 1024 * 10 bits / 7 seconds = 19.2K.
Hey, it's like I'm back running my 1992 BBS.
Re: (Score:2)
It is a fair comparison. That unnecessary bloat is the very "Parkinson's Law [wikipedia.org]" he refers to.
No mention of Telebit? (Score:3, Interesting)
What history of modems completely skips the Telebit Trailblazer? Roughly 18 kbps in 1985 - many years before 14.4k modems became common. Expensive enough to be out of reach of most BBS'ers, though. But worth the money if you were doing UUCP over a long distance call every night.
Missed the whole USR Courier saga (Score:3, Interesting)
My Modem Story (Score:5, Interesting)
I once worked at a place that had a DEC/VAX mini with a bank of about 8 modems for VT100-compatible terminals. If there were modem complaints such as dial-in problems, I had to first figure out which modem was connected to which phone number. Others didn't always keep the map up-to-date. Plus, it used busy-roll-over.
The test phone was a ways away from the modem bank for the VAX minicomputer, so I had to keep the modem trying to connect long enough until I got there to see which modem answered the call (via LED). The only easy way I found to do this was to manually whistle an acceptable modem tone into the phone in order to trick the modem into thinking I was a modem trying to connect. This would keep it trying long enough to allow me to run from the test phone to the modem bank. It had to be the right pitch and wavering to work most of the time. I got pretty good at it after a while. I learned to "speak modem" a bit.
A computer-room technician once saw me whistling modem sounds into the phone and running back and forth. I later told him why, and he told me I was nuts and mumbled something about whistling sweat nothings to my robotic girlfriends.
Re:My Modem Story (Score:4, Funny)
A computer-room technician once saw me whistling modem sounds into the phone and running back and forth. I later told him why, and he told me I was nuts and mumbled something about whistling sweat nothings to my robotic girlfriends.
That sounds like a great start to a new sig.
I love modems (Score:2)
No I really do, I love modems. I grew up with them. And calling BBSes (and running one for several years) was really great.
I don't think I would have gotten into programming (my career) if it wasn't for the BBS scene of the 1990s.
Init strings (Score:2)
Man, remember writing init strings? That was a skill. Every new modem you got, you sat down and figured out how it interpeted the AT codes. Then, you had to fine-tune the string. How long did your line need dialtone before you dialed? How fast could you dial the numbers (in ms)? Of all my memories of dial-up, I think some of my best are of tweaking the init string so you could dial in as fast as possible. After all, there was a good chance you'd get a busy signal; you need to hang up and redial ASAP!
Old Computer Code 5 (Score:2)
Solve:
http://www.geocaching.com/seek/cache_details.aspx?guid=9a9af759-f3f6-4edd-88a5-31e0d8b30d57 [geocaching.com]
Bah, kids nowdays -- 42bps modems (Score:4, Interesting)
Bah, kids nowdays, so spoiled with the megabit modems.
Before the Bell System modems, there were over-the-airwaves modems, going back to 1930 or so. The endpoints were teletype machines, whirring away furiously at 60WPM, 7.42 bits per character. ( 5 data bits, one start bit, 1.42 stop bits).
The modems wee made up of L/C filters and a trunkful of vacuum tubes. I used to have a military modem, a CVV -something, that was the size of a suitcase and weighed about 60 pounds. 42 BPS.
But it could do 42BPS over a noisy fading shortwave radio link, all day long, while taking direct mortar rounds, and never say "NO CARRIER."
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.
Re: (Score:3, Informative)
Just reading http://en.wikipedia.org/wiki/Novation_CAT [wikipedia.org]
Neat use of transfer bandwidth ideas
Re: (Score:3, Interesting)
Yeah here Telecom Australia charged $10000 AU dollars per year for a DDS connection (thats 9600 bits per second, serial on a 25 pin D connector, point to point). Its a good service, but 10 grand?. The early limitations on modems not provided by Telstra were basically there to protect that business.