Having Fun With Dumb Terminals


For a long time now, [Morgan] has been wanting an old serial terminal. In a stroke of luck, one of his pals at the Quelab hackerspace scored an awesome ADM-3A terminal from a collector. It’s a historically significant piece of computing and UNIX history, so obviously [Morgan] needed to get it working.

The ADM-3A terminal pre-dates the famous DEC VT-100 terminal, but since [Morgan]’s new acquisition speaks RS-232, he had a good shot at getting it to work with one of his more modern boxes. He’s using a Windows laptop loaded up with FreeBSD in a VM to talk to the terminal. Surprisingly, the only additional hardware required was a USB to serial cable and a DE9-DB25 serial adapter.

It may not be as cool (or as loud) as Quelab’s Teletype ASR-35 they have set up for Zork sessions, but it’s great to see ancient hardware have some
use. Right now, [Morgan] is editing files with vi and of course playing Zork. Seems like there’s plenty of life left in this old dumb terminal. After looking for an old VT-100 for a while now, I’ve got to say I’m pretty jealous.

37 thoughts on “Having Fun With Dumb Terminals

    1. They’re never cheap, though. Did most companies throw them out years ago, and now there’s none left?

      I remember a place in the early 90s had quite a few . Mostly connected to little serial Ethernet boxes running over the building’s LAN. They’d mostly been superceded by PCs at that point.

      I learned Unix and C programming on a Wyse 60, I’d love to have one now. I think even a dumb terminal can have it’s capabilities expanded with modern software, eg run multiple terminals on one actual terminal.

      If anyone has a tipoff for cheap terminals… especially in the UK.

  1. way to go Morgan!

    My college (New Mexico Tech) had these hooked up to the DEC-20 (TOPS-20). The CS students started work at 11pm when the load average was reasonable. We would take over two terminals – while compiling, would play Star Wars on the other.

    My first job out of school was at Floating Point Systems. Everybody had one of these on their desk. Mine had all of the chips in sockets, so every once in a while I would need to open the case and re-seat the chips.

    And a shout out to Ray for the ADM-35 to play Zork on!

    Now if we can get a copy of the old DECUS Star Wars game…

        1. Please, no last names.
          The Singularity is already watching.
          We once shared a wall in the hall.

          Is that Morgan P?
          Do you think that monicker had anything to do with him growing up to be a hacker?
          Congratulations! Youth advances all electric, but some ways are better than others.

          1. Yep – that’s him. (P = Pascal) I don’t think the kid had a chance to be anything other than a geek. It was a matter of getting out of the way. I keep finding out about the stuff he is involved with (lots of open source). I warned him when he turned 13 that I didn’t want serious looking guys in black suits and badges showing up at the door. So far, so good.

            If he ever had a sister, her middle names would have been “Ada Grace”. Alas, his mother opted for one child. Her comment on a second child was “over your dead body”. She was a Marine – I did not think it was a figure of speech.

            Did you achieve your goal of the second worst house on the block? Find my number && give me a call. I can still hear that Wizard’s tape…. They have really destroyed the student culture at NMT – very sad. We did have a couple of students come up to Quelab last Sunday. I still see Al from time to time.

            All hail the Singularity!

        2. Please, no last names.
          The Singularity is already watching.
          We once shared a wall in the hall.

          Is that Morgan P?
          Do you think that monicker has anything to do with his hackiness?
          Congratulations! Youth advances all electric, but some ways are better than others!

  2. I did almost the same exact thing about 7 years ago. I used ubuntu instead, and a native serial port on an old laptop. I thought it’d be cool to get the ADM-3A connected to the internet. I found an IRC client and a jabber client and had it up and running with google talk.

    Unfortunately my ADM-3A has since stopped working (no picture at all). I’ll get around to fixing it eventually, it’s a sweet piece of vintage hardware. Mine is from 1977.

    I think it uses composite video internally (I found a service manual), so I should hopefully be able to hook it up to a different display to narrow it down to the digital stuff or the analog stuff.

    1. Is there such a thing as monochrome composite? There’s not a lot to modulate, I’d imagine just some sync pulses then just the pixel stream. Still yeah, would probably work on a composite TV if the signal rates are the same.

  3. “Surprisingly” all it needed was a serial port and serial connectors? It’s a freakin’ serial terminal! No, the nasty part isn’t the hardware connection, it’s getting the #$%! correct termcap entry…..

  4. Heck, i’ve got a super cool DEC VT-05 terminal.
    It’s been at least 15 yrs since it’s been powered
    up. It will come to life, but seems the keyboard is
    not producing any output on the screen.

    If anyone is interested, it’s for sale. Local pick up
    in NJ is preferred (the mofo is *heavy*!)

  5. It’s a serial terminal. The hardest part is getting the right combination of USB-to-serial and DB9-DB25 converters plugged together. Then you just follow the copious instructions available online, in this case you’d use http://www.freebsd.org/doc/en/books/handbook/term.html

    I mean hell, I’ve used a VT-220 and an ADM-3A with my desktop, my laptop, a VAXstation, an Alpha, and some weird little ARM board I no longer remember. I guess I’m a master hardware hacker.

  6. lol some people dont know the difference between a smart/modern terminal and a DUMB terminal.

    the “dumb” terminal is nothing but converters inside, ZERO CPU, ZERO microcontroller…
    but it DOES have video/text-video RAM and a CHARACTER ROM and a memory counter

    ***_ BECAUSE IT HAS NO CPU! / uC! _***
    and most of them had hidden dipswitches to enable/disable any settings, like local echo, it isnt _supposed_ to show anything on screen until something is connected to it.

    PS: a “smart” terminal is the usual microcontroller projects we are used to discussing

    PPS: remember that back then, the “brains” took up an entire room and had LOTS of serial ports

    the thing on your desk was only a RS232->NTSC converter plus a button->RS232 converter

    PPPS: i never said anything about anyone, just that everyone i talk to thinks a terminal is a desktop computer with custom os/software/cashdrawr/ect, those are “smart” terminals aka computers

    1. Still a lot of the later terminals were smart, simply because it made sense to use a CPU to implement many of the functions. And once you’d put a CPU in there, you could add a huge amount more functions. Made more sense than inventing baroque hardware, switches and gears, to decode escape codes.

      Still, thinking about ASCII, it’s codes make sense when it comes to designing teletypes. If the 64 bit is on, it’s an alphabetic character. With the 32 bit on too, it’s lower case. 32 + 16 = numeric character. Etc! But I’m sure dividing the character set up into categories denoted by the higher bits was a deliberate and useful decision.

  7. I have a question i buy an adm3a siegler and i conect todas my computer with a cable usb adapter serial, i use freebsd in ttys i set ttyu0 “/usr/libexec/getty 3wire.9600” adm3a on secure i dont’t why don’ show nothing y type in adm3a don’t show no letter can You explain what i can do i am new in unix and Linux i need help please

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