December 4, 2009

Dialing a Modem in 1984

Filed under: Main — Dan Gookin @ 12:01 am

My very first modem.

My very first modem.


Connecting to the ubiquitous Internet just isn’t a chore at all today. But take the Wambooli Wayback machine to 1984 and you’re in for a surprising adventure of online terror and surprise!

Modems weren’t that popular 25 years ago. Rarely did they come with your computer; almost always the modem as an afterthought purchase. I mean, who wanted one? What would you call?

There were two types of modems: internal and external. I preferred the external because A) I could see the pretty lights, B) I could turn the thing off in times of woe, C) I could easily transfer it to a new computer, and D) it didn’t have the compatibility issues and conflicts of the internal modems.

Back in those days, modems came with telecommunications, or “Comm,” software. That software wasn’t very friendly. That was because most computer users back then were nerds. We loved the challenge! But even friendly software didn’t skirt the issue of having to know the dreaded modem commands.

O, I remember it well!

Most modems (but not all) used the Hayes Smartmodem command set. After starting the Comm program, anything you typed in that program was received by the modem. Mostly, I started with the AT command.

AT stands for Attention and it was the way you could confirm that your computer and the modem were on speaking terms with each other. It went like this:

AT
OK

You typed in AT and pressed the Enter key, the modem responded with OK. If it didn’t, the modem was either off, stubborn, or dead.

To dial the phone you used the ATDT command. DT stood for Dial Tone, as opposed to DP, Dial Pulse, for older non-touch tone phones. ATDT was followed by a phone number, as in:

ATDT5551234

After pressing Enter, you’d see the text Dialing displayed, and then you’d hear the modem pick up the phone line. (Hopefully the modem had its own line.) Then you’d hear the number dial. Sometimes the numbers would appear as they were dialed:

Dailing 5551234

Then you might see Ringing or something. Eventually you’d see Connected (hopefully) and you’d be online, chatting it up with another computer somewhere. At that point, all the text you’d see in the Comm program was coming from the other computer.

Yes, it was all text. All of it.

Hanging up the modem at the end of the call was accomplished in a number of ways. When I wrote communications programs, I’d simply drop the Data Terminal Ready (DTR) line on the serial port, which hung up most modems instantly. Most Comm programs did things that way.

You could also type the modem’s escape sequence, such as *** and then you’d see the OK prompt. Typing ATH would hang up the modem.

For external modems, you could always turn the dang thing off – another advantage to an external modem.

Finally, and most desperately, you could simply unplug the phone line.

Man! Those were the days!

4 Comments

  1. I bought my first modem in about 1992. At 2400 baud, it was twice as fast as the one I used at work. I also opted for the external model, and had to get a serial port switching box because I only had two ports but three RS-232 devices. The biggest problem I encountered was noise on the phone line, which frequently caused the modem to drop its connection, usually in the middle of some massive transfer.

    On the software side, I was a big fan of Datastorm’s Procomm Plus. I had already been using it for VT100 terminal emulation at my job, so I had no trouble adapting it for modem control. It had many cool features, such as assigning custom strings to Alt-key combinations, it came with its own programming language called Aspect, and had a “host mode” which could be used to set up a primitive bulletin board. Back then, I was the expert. Now I just call the IT guy when I have a problem.

    Comment by sean bernard — December 6, 2009 @ 3:14 pm

  2. My first modem was 300 bps. I remember taking 15 minutes to download a 15K file. It was insanely slow. The 1200 bps modems came out soon afterward, but they were very expensive. I held out for the 2400BPS modem. Then I got, in order: 9600BPS, 14400BPS, 24Kbps and finally the 56Kbps standard we have today. I once had a whole stack of modems out in the garage. I might have one or two left just ’cause.

    I didn’t use Procomm Plus, but I knew about it. I believe I used a program I wrote myself for the most part. Anyway, those were the days…

    Comment by admin — December 6, 2009 @ 3:56 pm

  3. Dan- Since were taking another stroll down memory lane, I thought Id hit you up for some more questions about what it was like back then.

    -I imagine you knew people who worked in the computer industry back in the 80s, is it true that the Dec-XX series and Vax running unix and vms respectively were the main computers used in business? Did they teach classes on how to use unix and vms in junior colleges back then? When did editors like vi and emacs finally make it to home computers? I heard that old programmers loved programming with the Dec-XX series, I wonder if there are people who still have those computers still running?

    -You mentioned on a previous blog post that prolog was popular with AI people in the late 80s, how about Lisp and Scheme? I heard that in the 80s they build very expensive computers that did nothing but run lisp.

    -Did they have any open source operating systems in the 80s? And if they did I imagine they had to be flashed onto ROM.

    Comment by BradC — December 15, 2009 @ 5:22 pm

  4. is it true that the Dec-XX series and Vax running unix and vms respectively were the main computers used in business?

    Well, big businesses use a variety of minis. Most small businesses didn’t use computers. Where I worked, we had a TRS-80 Model 16 (68000 CPU) running Microsoft Xenix. That was my first taste of Unix on a daily basis as I was the admin.

    When did editors like vi and emacs finally make it to home computers?

    They never did. There were lots of editors to use on the PC, especially DOS’s silly EDLIN. I used a great little editor, I forget it’s name, but it was sweet. Used the WordStar key commands, which were handy.

    I heard that old programmers loved programming with the Dec-XX series, I wonder if there are people who still have those computers still running?

    Dunno.

    You mentioned on a previous blog post that prolog was popular with AI people in the late 80s, how about Lisp and Scheme? I heard that in the 80s they build very expensive computers that did nothing but run lisp.

    Lisp required too much horsepower to run on a PC, so no one did. There were “tiny Lisp” implementations, but most folks I knew programmed in BASIC, C, or Assembly. Pascal was popular, but used mostly by dorks at university. For development, you used BASIC, C, or Assembly.

    Did they have any open source operating systems in the 80s? And if they did I imagine they had to be flashed onto ROM.

    Nope. Nothing was free, and if you got it free you stole it. The OS came with the computer and few people switched OSs, mostly because hard drive storage was very expensive. I’ll write about that someday.

    Great questions! Thanks!

    Comment by admin — December 15, 2009 @ 10:59 pm

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