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posted by hubie on Monday January 16 2023, @01:25PM   Printer-friendly
from the dialogue-from-a-simpler-time dept.

https://www.windytan.com/2012/11/the-sound-of-dialup-pictured.html

If you ever connected to the Internet before the 2000s, you probably remember that it made a peculiar sound. But despite becoming so familiar, it remained a mystery for most of us. What do these sounds mean?

As many already know, what you're hearing is often called a handshake, the start of a telephone conversation between two modems. The modems are trying to find a common language and determine the weaknesses of the telephone channel originally meant for human speech.


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  • (Score: 5, Funny) by Opportunist on Monday January 16 2023, @03:12PM (1 child)

    by Opportunist (5545) on Monday January 16 2023, @03:12PM (#1287058)

    ATM0 was a command you could use to turn the speaker off and have the modem do the whole negotiation without the whole buzzing and beeping. For a while, since our professors didn't like profanity, we told people who were blabbing too much or to long to "ATM0" instead of STFU.

    Just another thing the young people don't understand anymore. Like that joke:

    What do internet junkies and F-18 pilots have in common?
    Both break out in cold sweat when the screen says NO CARRIER.

    Try to tell that to a person under 20, they'll just look at you and ask what a carrier had to do with the internet. And yeah, gramps is gonna go take his afternoon snooze now, right after taking my meds.

    • (Score: 2) by TheGratefulNet on Tuesday January 17 2023, @03:05AM

      by TheGratefulNet (659) on Tuesday January 17 2023, @03:05AM (#1287177)

      when I have to youngun-splain what NO CARRIER means, you are already on two different planes of existence.

      "you had to have a home phone, and it went into this sponge rubber thing. and if anyone picked up in the house, there would be screaming and redialing, not necessarily in that order"

      2nd use of GOML today. wonder what #3 will be.

      --
      "It is now safe to switch off your computer."
  • (Score: 4, Interesting) by bzipitidoo on Monday January 16 2023, @03:12PM (1 child)

    by bzipitidoo (4388) on Monday January 16 2023, @03:12PM (#1287059) Journal

    > put their data through a special scrambling formula

    Why doesn't the article say what this "special" formula is? A big part of it is simply data compression. Tends to equalize the quantities of each of the codes, that is, compressed data has roughly equal numbers of 0 bits and 1 bits. "Scramble" makes it sound like the data was being encrypted or randomized in some fashion.

    > The first modems even used the telephone receiver like humans do, by talking into the mouthpiece, until newer modems were developed that could directly connect into the phone line.

    From what I've read, the reason for that was political, not technical. Had it not been for Ma Bell being jerks about it, abusing their monopoly power to insist that nothing but their own equipment was allowed to connect directly, the direct connection modem would have been first, and the acoustic modem would never have been developed at all. The article gives the impression that a direct connection was a technological advance.

    • (Score: 2) by canopic jug on Monday January 16 2023, @03:35PM

      by canopic jug (3949) Subscriber Badge on Monday January 16 2023, @03:35PM (#1287067) Journal

      Despite the mistake it does seem to be an interesting exploration of the technology. I would also note that the blog post in question is from 2012 (just over 10 years ago) and appears the be the year her blog started.

      --
      Money is not free speech. Elections should not be auctions.
  • (Score: 3, Interesting) by VLM on Monday January 16 2023, @03:13PM (3 children)

    by VLM (445) Subscriber Badge on Monday January 16 2023, @03:13PM (#1287060)

    DTMF stands for "dial tone mutha fucka" or sometimes "dual tone multifrequency" signaling standard (as opposed to using pulses of loopstart or groundstart LOL)
    Anyway look at a spectrogram and there's two "bands" of four tones with a gap around 1004 hz (I know why; its a long story). MF trunk signaling used different tones, long story.
    Look at a dial pad and imagine the "low band" along the rows with lowest at top and highest at bottom, and the "high band" along the columns with lowest at the left and highest at the right, like if you had coordinates the origin would be stereotypical computer upper left corner.

    So, the point of this ramble is in the linked poster, the caption claims the number dialed is 1-570-234-0003 and the first digit is the leftmost column, top row, thats "1", then second from left and second down thats "5" and then leftmost column and third row that's "7" and so forth.

    Also if you look at the poster time scale the guy had not optimized his "AT" command strings as perhaps default tone length was 100 ms but IIRC my local switch could interpret as fast as 50 ms and I could dial much faster than this guy via a simple S register change in his dialing string.

    I was pleasantly surprised to find out recently that the entire run of BSTJ is available on archive.org. Lots of fun reading material there.

    • (Score: 2) by sjames on Monday January 16 2023, @10:14PM (2 children)

      by sjames (2882) on Monday January 16 2023, @10:14PM (#1287150) Journal

      Supposedly, MF has been phased out everywhere since last century in favor of out of band signaling, but as recently as 5 years ago when a switch was malfunctioning I heard the 2600 tone followed by MF when making a call. It's not clear to me if that would have been exploitable or not since I don't even own a bluebox.

      • (Score: 2) by SDRefugee on Wednesday January 18 2023, @04:53AM (1 child)

        by SDRefugee (4477) on Wednesday January 18 2023, @04:53AM (#1287322)

        hehe Back in the early 80s, I had a friend who could, using his mouth, whistle down quite accurately that 2600hz
        tone. For those of us who couldn't hit 2600hz with a whistle, there was always the Capt Crunch whistle, that pretty
        much hit it on the nose. We used to phreak the phone a LOT..

        --
        America should be proud of Edward Snowden, the hero, whether they know it or not..
        • (Score: 2) by sjames on Tuesday January 31 2023, @04:27AM

          by sjames (2882) on Tuesday January 31 2023, @04:27AM (#1289430) Journal

          I tried, but I never managed to reliably whistle 2600. I do remember a comprehensive terminal program for the C64 that included bluebox and other useful tones.

  • (Score: 5, Insightful) by DannyB on Monday January 16 2023, @04:12PM (3 children)

    by DannyB (5839) Subscriber Badge on Monday January 16 2023, @04:12PM (#1287076) Journal

    In 1987 I worked on a product called Timbuktu on Macintosh. This was screen sharing over the LAN. (not modems) When we began this, we were not sure that screen sharing on Mac was even possible, even on LAN, nevermind modems. CPU and memory limitations of the day, etc. But we built a prototype and it worked.


        I patched every QuickDraw call in the OS. If screen sharing was off, then each patch simply jumped to the original OS routine. If screen sharing was on, then all of the parameters for this graphics operation were sent over the network so that it could be repeated on the "viewer" on the other end, and then the original OS routine was called. In addition to this, we had to deal with certain "badly behaved" applications *cough* MacPaint *cough* and *cough* Hypercard *cough* that would write pixels directly the the screen not using QuickDraw. So I kept an array of "checksums" one checksum per raster line of the screen. In the background we continuously, but slowly, scanned the screen calculating the checksum of what is on screen watching for any pixel changes on screen that resulted in a different checksum than we expected. (Also when we did QuickDraw operations, we recalculated the checksums strategically.) Now we could, if necessary, re-send rectangular areas of pixels to the remote end for these badly behaved programs.

    For some small bits as needed, I discovered that Motorola 68000 was a genuine pleasure to program.

    In about 1989, I worked on Timbuktu/Remote, which was screen sharing over modems. A number of vendors of high speed modems were very interested in our application and sent us sample pairs of their modems. These modems were typically about 19200 or more bps. Each modem was typically in the low thousands of dollars. It was a specialized market, at this time. to have modems that fast. I ended up with a pair of modems on my desk. Then another pair stacked on top of the first pair. Then eventually two identical stacks of modems.

    First, it was interesting to note how different all of the AT command set extensions were. It was also interesting how very different all of these modems sounded when negotiating. (This was before there was a single standard for these speeds.)

    Standards did appear for high speed modems. Yea! You could now have modems of different brands talk to each other.

    However, there was a Hayes modem called the Hayes V-Series 9600. It did NOT comply with the standard, despite its deceptive name. It's protocol was different and it sounded quite different. It had excellent bandwidth. But it also had something else the other modems did not have -- low latency. All of the other high speed modems of the day were optimized for throughput and not low level latency turnaround. Thus the Hayes V-Series worked best for moving the mouse pointer around on the screen and seeing the result on the other screen in much closer to real time.

    Timbuktu/Remote was nominated for a MacWorld award. I had to go there in case we won, to accept it. It won 2nd place. I no longer remember what won first place that year, but I agreed that it deserved 1st place.

    I really wished that the Hayes V-Series modems had become the "standard". They had superior performance in both bandwidth and latency. I'm sure Hayes wanted to keep it proprietary to sell only their modems. And they were a leading brand already.

    Decades later, I also have personal knowledge that small data boards for a certain sat phone system use AT commands. I won't say any more about that.

    One other thing, not only were modem makers interested in our product (still in development), but AT&T was interested enough to jump through a number of hoops to arrange to get a pair of ISDN lines in our office in the midwest. They even had to lease some lines for part of that setup. AT&T was looking for reasons to be able to sell ISDN. Of course, dial up internet came along, then cable modems, etc.

    --
    People today are educated enough to repeat what they are taught but not to question what they are taught.
    • (Score: 0) by Anonymous Coward on Monday January 16 2023, @06:51PM (2 children)

      by Anonymous Coward on Monday January 16 2023, @06:51PM (#1287105)

      Your post motivated me to try to find out what application beat you out for the MacWorld prize and I stumbled upon this archive [vintageapple.org]. I didn't find what I was looking for, but I did enjoy looking through some of them old magazines bring back memories of those early days. I never personally owned a Mac back then, but I did use them going back to 1984 or 1985 (we had one in a lab, but all I used it for was to play Dark Castle and some kind of map-based battle game where you would try to discover the map, build bases, send out scouting jet sorties, etc. and try to take over the map before the CPU did--dang if I can't remember what that game was called).

      • (Score: 0) by Anonymous Coward on Monday January 16 2023, @08:11PM

        by Anonymous Coward on Monday January 16 2023, @08:11PM (#1287128)

        Ah, I think that game that I mentioned was Strategic Conquest [wikipedia.org]. I would have played probably version 3 because I saw it around 1991.

      • (Score: 2) by DannyB on Monday January 16 2023, @09:09PM

        by DannyB (5839) Subscriber Badge on Monday January 16 2023, @09:09PM (#1287142) Journal

        I looked. I can only find "Netopia" which is what the company became after I left. When I was there the company was "Farallon". The award I mentioned would have been in about January or February, if my ancient memory is not failing me. About 1990 or thereabout.

        --
        People today are educated enough to repeat what they are taught but not to question what they are taught.
  • (Score: 2) by mcgrew on Monday January 16 2023, @07:22PM

    by mcgrew (701) <publish@mcgrewbooks.com> on Monday January 16 2023, @07:22PM (#1287115) Homepage Journal

    ...from posting in this thread.

    --
    mcgrewbooks.com mcgrew.info nooze.org
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