IBM Selectric Typewriter & its digital to analogue converter
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- Опубліковано 6 лис 2010
- Using slow motion video Bill Hammack, the engineer guy, shows how
IBM's revolutionary "golf ball" typewriter works. He describes the
marvelous completely mechanical digital-to-analogue converter that
translates the discrete impulse of the keys to the rotation of the
type element. (This is the typewriter featured on the television series Mad Men.) - Наука та технологія
We had these in our typing class in high school in the 80's, the best prank was getting to class early, and while no one was around, lift the locking lever at the top of the ball. When class started, especially when there was a timed test, 20 or so selectrics launched their ball out of the machine!! Yeah, it was epic.
that must've been expensive if broke
@@alexradu1921 metal ball, carpeted typing lab. Still makes me laugh when I think about it!
Had me a good laugh. Thanks!
@@markk3652plastic ball with silver-coloured plating on top. I serviced them.
@@alexradu1921This was in the 80's, so planned obsolescence wasn't in full effect yet.
Amazing how violent it looked when it was slowed down.
So violence is amazing?
+Harald Jan Dahle Isn't it? We watch violence every day after way. If not amazing it is quite entertaining.
@@petrofilmeurope wow you really got them didnt you
@@VineFynn some people are so stupid they only took one word out of a sentence
Another slow mo in the original very cool commercial:
ua-cam.com/video/vNUEUth7qjc/v-deo.html
"Commercial for IBM's Selectric Typewriter 1960's"
The wiffletree is actually incredibly genius, wow. I would never have thought of such an elegant design.
Many years ago, I used to repair IBM Selectrics, so I am quite familiar with their workings, and to this day, I am still astonished by their exquisite design - they are a MASTERPIECE of mechanical engineering!Yet, I would argue that these are not digital-to-analog, but binary-to-decimal converters, since their "whiffletrees" can generate only integer, or decimal, movements. You could not, for instance, have 1.643 or 2.165 increments of rotation, only 0, 1, 2 or 3 increments. (In the case of vertical "tilt")
flurng while I understand your argument I think with that argument you could say, that even today there are no real binary to analog converters. When we convert binary to „analog“ we take discrete binary numbers an turn them into other discrete numbers. The resulting numbers are considered „analog“ when the gaps between them are small enough so we can just neglect them.
In your example one could certainly build a decent mechanical device that converts digital numbers to 0.000, 0.001, 0.002 etc. and you would sooner or later reach 1.643 and also 2.145 with that. We would consider this output as analog, nevertheless its rather „pseudoanalog“. The gaps are just 0.001 sized instead of 1.
Turns out there is no such device that could generate a real analog signal out of a discrete digital one. A D/A converter is in fact a function f that transforms a number into an other number. For a given (digital) input number we want only one possible result as output, everything else would result in nonsense. That means we want the f to be injective.
Now since the input is discrete and finite (there is a maximum digital number that a computer can store) we can not use f to generate an continuous output set out of the input. Since the continuous output has an infinite amount of numbers between every two numbers of that set, we would simply run out of input numbers before we could „hit“ every possible output.
@@schievel6047 interesting point. However, 'time' can be used to bring continuity in the output space. For example, an inverter working with a DC 12 Volt battery can give a close to sinusoidally varying output using clever 'circuit switching' electronics.
Well, it turns out that reality is fundamentally discrete, not continuous, so really digital vs. analog is a question of the resolution of a system vs. the resolution of its measurement.
@@schievel6047 how you discuss such an complex technical or niche topic with such a fluency...think we have a core techie in comment section....nice to see you people around.
@@stallio5612 oh thank you very very much. I really appreciate your compliment because English is not my mother tongue and I am always worried when I try to discuss a math topic in English people only under nonsense 😅
This blew my mind when we opened one in typing class. Looks way cooler than programming a keyboard.
The mechanical precision of something so old is just way too fascinating.
"So old"
Wow, thank you Alec from Technology Connection's for bringing me here. Fascinating engineering indeed!
thank you dankpods guy for pointing to Alec Technology Connections that brought me to this channel, fascinating engineering indeed!
Thanks for the explanation. I always wondered how that mechanism worked.
I was a reporter when Selectrics first came into our newsroom in the 1970s. We used an OCR ball and typed on special copy paper. Those were then fed into an OCR machine -- half the size of a refrigerator -- that produced a punched paper tape that was read by a Compugraphic typesetter -- the full size of a refrigerator. That spit out justified columns of type on photosensitive paper that had to be developed and pasted down and shot for a page negative that was used to burn an offset printing plate for the press. Quite the convoluted process.
Then Macs came along.
I always loved the IBM keyboard, so i was happy to find a Selectric II at a thrift store for $5 last year. After a cleaning and lubricating, it works fine. (It came out of our county courthouse so it was well-serviced -- there's a lot of junkers around.) A Yahoo group named golf ball typewriters is a great knowledge base to keep them running, and the ribbons and correction tape are still readily available.
I grew up watching my mom type on one of these. She was so good she could even create forms with it. Super straight lines and columns.
Yep me too. I can still hear the sound of my Mom chopping away on her Selectric back in the 70's.
Cool! I was an instumentman in the Navy. I repaired the Selectric and the Selectric II on board my ship. You have no idea how many typewriters there were on an aircraft carrier back in the day.
My grandpa worked on designing that ball carriage system for IBM
And yet your username has "chemtrail" in it... your family went off the deep end apparently.
@@audilicous it's so myopic of you to interpret it like that - in fact it's clear from the guy's username and videos, that it's the opposite of what you wrote
@@audilicous I think he's being sarcastic with the name, also, it isn't only dumb people fall for conspiracies, some people are smart, know they're smart and so, want to think differently to others (subconsciously) and so they are more likely to fall for things that are believable.
@@ChrisOReilly Chemtrails are real. The conspiracy is trying to hide the truths about them.
@@artsmith103 I have been in the cockpit of commercial jets a number of times and no switch causes "chemtrails", it's the stupidest idea I've ever heard.
I enjoyed watching this! It brought back a sweet memory. In 1979 I bought an old IBM Selectric I/O typewriter, that had electromagnets connected to each branch of the wiffle tree. I was experimenting with a new type of keyboard, and built an interface so that my key switches would fire the right magnets to produce the character that matched the keys. My new keyboard design did not make me rich and famous as I had hoped, but it was tons of fun figuring out how it all worked - because when I bought it, I had imagined the inner workings very differently from how they really work.
Seeing how the ball is position is amazing and I was happy to see that. I'm amazed that after decades, the linkages and cables haven't been stretched or worn out and not longer position the ball correctly.
But, I would like to see how the keys translate into the movement of the wiffletree.
The only cable in the selectric is the one that moves the carriage!
Tilt and rotate are translated to the hall via thin metal tapes that go around pulleys out of frame, and what the video calls cables are in fact metal rods!
I got curious about this typewriter, searched for a couple of videos and was blessed with this amazingly concise and detailed explanation of it's inner workings. It's awesome this kind of content is free, what a time to be alive
Thank you
Hello again and greeting from a Technology Connections viewer
I cried when that machine was introduced. It rendered my Underwood # 5 obsolete. Ah, progress!
Your Underwood STILL ISN'T completely obsolete.
Your Underwood #5 will still work even if there’s a power cut. The Selectric, however, will not. Progress?
@@hazelanderson1479 Exactly. I wish I could upvote that comment about five times. 8)
@@suprememasteroftheuniverse Not sure if using an ink ribbon more than once is worth the savings compared to the outcome. 😉
@@hazelanderson1479 But who's going to type in the dark, anyway.
My dad's cousin, Thurston Toeppen, designed a number of critical parts for the selectric and is named on many patents. In particular, he designed the latching mechanism that securely attaches the ball ("ocular") to the shaft.
My sister typed so fast that a selctric began to type garbage. They bought one for her that had memory in between her key strokes and output. When she would stop typing, it would output for about ten to twelve seconds. She was some kinda fast.
That was Fun to imagine
That was only because the selectric was out of adjustment.
I remember being a kid in the early 90s and trying to type really fast on a Brother electric typewriter, to my astonishment it had some kind of buffer so it behaved exactly like that, when I overrun the mechanism it would continue typing as I stopped my key strokes. I remember taking it apart just to have a look, it was rocket science for me haha
Wow
Considering this thing can type 14.8 characters per second, and the average amount of letters in a word is 6.7(lets say 7 for caution); to get a result of 10 additional seconds of typing once stopped, she would need to type at 127 words per minute PLUS an additional 21 words per minute for a whole minute to result in 10 seconds of continued letter input.
This is 148 words per minute which hard to believe.
The IBM Selectric were awesome machines. My mother was a secretary and she loved them. And my father used to work for PanAm and I remember back in the 70s their reservation system terminals were these typewriters.
Whenever I watch your videos, I end up with MORE questions than I had before! (That's because I didn't know enough to have questions in the first place). Thanks for your videos!
Ok, that was the intro ... where's the rest? Now I'm intrigued.
Don't be. It was wrong anyway.
@@timhofstetter5654 [citation needed]
@@Number_055 Mo citation actually necessary. There's nothing analog about the IBM Selectric; it's purely mechanical-digital (base 4 and base 22). The whole premise upon which this video was based was incorrect.
@@timhofstetter5654 It uses discrete analog output. Mechanical levers by nature are analog.
@@darkwood777 Neither of those statements even begins to be true. Mechanical levers with a finite number of orientations / positions are by nature digital.
Your fingers are levers, and they are the prime origin of the term "digital". When you count on your fingers, they have two positions: up (1) and down (0). There is no "halfway" (~0.5) position. There is no one-third (1/3) position. There is nothing analog about your fingers when you're counting.
Anything with a finite range of positions is digital. Analog is infinitely variable with or without optional limits.
Oh Nostalgia, my mom had one of these when I was a kid! When I was about 6 I was allowed to use it a bit, I'd goof off on it or write diaries, and I'd always puzzled at the "golfball".
This solved that ancient childhood mystery for me. Thank you!
Cool! My grandfather, Horace smart Beattie invented the selectric for ibm. I’ve got the 1 millionth one sitting in my family room with a plaque on it and everything. Neat!
I was trained on Selectric repair and maintenance back in 1978. We were told that the inventors of the Selectric 1 went insane because the mechanism was so complex. Do you think that there is any truth to that rumor?
@@MichaelHutton1 lol, nope none at all. He retired as a vp in the 80s, had a horse farm and had very thought provoking questions for his grandchildren. Good man.
@@Greenskycity thanks. It’s nice to finally get such information even 44 years later.
That's so cool! ⌨️📝
Get it? Type write(r)! 😁
When he showed the two cables, it made me think: So many basic mechanisms are used in different things that have nothing to do with one another. The cables he showed in this typewriter work the same as the shifter cables in my car, which uses two cables to move three shift forks. The mechanism that you see in old style windshield wipers to distribute the load from one point evenly across the entire blade is also seen in hydraulic carton clamps that are attached to forklifts to carry appliances. The list of non-associated machines that use the same idea is endless and amazing. I love these videos, and can't wait to watch more.
Wow! Fantastic!
Oh boy... when I beginning my career as a developer in Brazil, these machines were absurdly expensive and of course, whenever one was available, there was always someone who wanted to interface it with and print from the computer... what a fun times were those.
My mother owned an IBM Selectric for the family business. the first few seconds of this video, that specific sound, took me all the way back to childhood in the late 70s/80s.
I'd already seen this video years ago, but Technology Connections sent me here with his typerwriter video.
Extremely concise. Could have heard way more about this machine I think.
I still remember my first Selectric. Nothing like it ever existed before. It was very advanced for it's time. Thanks for taking the time to explain this incredible machine !
I've always wanted to pull an IBM Selectric typewriter apart, to see how it was able to control the ball with each key stroke. I understood the "draw bands", but I didn't know the mechanism used to pull the draw bands the right amount, for the letters on the ball to strike the page perfectly. With this explanation, I can see that the system is clever, but simple enough to be reliable. I've NEVER had a problem with these typewriters, other than breaking a draw band. I did notice, that the draw bands were connected to shieves on levers, allowing the head to span margin to margin, with no errors in centering up the letter to strike perfectly. Great video!
Amazing.
I picked one up once at a thrift shop just to admire the way that it worked. One of the most impressive mechanical products I can think of.
In 1980 I assisted my friend Todd as he converted a Selectric to be a printer. He also built the interface board. I didn't understand how the Selectric worked, but he made the entire process seem simple. Now, 42 years later, I understand the Selectric. Thanks for this!
How can no one like this video? Decades ago late 70's my mother was taking a business class, our dad rented/leased an IBM Selelctic-2 with the ball typeface for her to use at home. I remember those typewriters were very expensive over $1,200.00 or higher. I was able to use it, when mom was not working on it. It was an amazing machine. Some years later, I found one at a garage sale had some issue. Decided to get it repaired. Cost was under 150.00.
Now we are waiting the video explaining how to link a computer to a selectric ... ;)
en.wikipedia.org/wiki/IBM_Selectric_typewriter#Use_as_a_computer_terminal
saa82vik It existed in 71 or 72, it consisted of 5x8” magnetic card that was inserted into a writer/reader. I can’t recall if the Selectric itself was able to store part of the document until it was transcribed on to the magnetic card.
I built one, in 1983. It hooked up to an Apple ][ using a parallel (8 bit) output card. The challenge was writing the driver in 255 bytes.
@@matthewlitvak2695 You are referring to one of the Mag Card machines (there was an original Mag Card, and then a Mag Card II), based on the same system of reed relays and solenoids. But IBM also had computer terminals based on the Selectric. The Mag Card had a separate console handling all the electronics but was not connected to a computer. The IBM Memory Typewriter put the entire system within an enclosure just a little larger than a regular Selectric.
@@ErikBruchez I’ve got a very vague memory of the entire system, I was 10 or 11 when it came out in 72. It was initially kept in the file room at my dads law firm in Chicago. I remember the card holder and the reader, I just can’t remember how it operated and whether you could edit a stored document.
Great description of the working of the Selectric I spent 20 years working on Selectric and you do the best at demystifying the machine
Thanks for the video. I’ve used Selectrics for years and never actually was curious how they worked. It’s all so simple now.
Man you are amazing - Thanks for the explanation of an accurate mechanism designed by our senior tech genius.
I would've liked to know more about the other components of the typewriter, but this is incredible!
This video is about to get a lot more popular.
Why?
We were sent from a typographically smooth youtuber named Alec from Technology Connections.
@engineerguyvideo Fascinating! Hard to believe that this thing even works, and works as well as it does!
One thing that has ALWAYS fascinated me is how we design and machine these small parts and devices to the exact level of precision necessary for these devices to work - repeatedly.
Have you ever considered making a "measurements" engineering video? I would it! I know today that smaller measurements are made possible by using lasers and sensors, but what were the standards for back then?
This is such a GREAT video. I am also a Selectric fan and have the service manuals that describe this. I remember first reading this section and thinking how brilliant the design was.
I am a collector of IBM Composers, a machine based on the Selectric.
I’m just barely old enough to have used a typewriter as a kid. I had no idea something like this existed until now. What an absolutely amazing design! The mechanical precision blows my mind. Seems a lot more elegant to me than throwing tons of modern computing power at a problem.
One of the earliest "electronic" typewrites was made by IBM based on the selectric. They basically used the Selectric with a similar mechanical mechanism on the keyboard to encode the keystroke which went into 7 or 8 on/off switches. The encoding went into their electronics. Then their electronics fired solenoids that where connected to the levers that do the tilt and rotate. Basically the computer was shimmed onto the control rods.
Oh no! I wanted to see more slow-motion footage of it in use! What a crazy machine!
I really love the videos i've seen so far. You are an excellent presenter.
Another terrific video showing the sheer ingenuity of people. I love the engineering of typewriters and still use an old Olivetti Studio 44 typewriter. It's min mint condition. :D
Technology Connections channel led me here. Stating it for marketing purposes.
Wow, I always wondered how this typewriter worked, thank you engineer guy!
My father . .who rest in peace, he was a Lawyer so he used to have all kinds of typing machines this one's was like the latest of all.
That is so amazing. I own two typewriters and know how they work. I've seen a Selectric as well but never saw it in action. Cheers!
Great work bill ! I thoroughly enjoy all your videos
This channel is the OG of engineering explained genre. Just when I thought I had binge watched all his videos, I find a new topic I somehow missed.
Fabulous - very nicely explained and beautifully filmed. Thanks for this.
I worked on those for 18 years in the Eighties. Extremely well engineered, complicated machine and took a long time to get confident working on them. If You could competently service one, You can get a job anywhere in the office service industry as there wasn’t a single office that didn’t have at least a couple. They retailed at over a thousand dollars then! I remembered We had a cocky, overly confident copier tech that went to school to cross train on them, and He came back very humbled. Never worked on them after the schooling. I, on the other hand, cross trained on copiers and found them stupidly easier. I was the first choice for the dispatcher to send anywhere as I could now work on both. I quit my job after seeing manager position go by Me more than once, and I opened a jewelry store, in which manufacturing jewelry was My first love and had been doing that out of My parents garage when I was 17. I own Gipson Diamond Jewelers in Garden City, KS and My Son works along side of Me. I’m so grateful My old job didn’t pay well or I never would of taken a chance going on My own. Boy, this video brings back some memories, though.
The complexity of the selectric is truly remarkable as is how few folks understand or understood the elegance of the design. Thank you Bill for explaining how the type element works as well as the analog to digital component. Perhaps you can discuss how the correcting mechanism worked on the old models prior to correction tape.
I came here today just after the video of Technology Connections about the typewriter, release on the second of August 2022.
August 6th for me! 📆
I have always wondered how golfball printers worked. That is far more wonderful than I had imagined. Very ingenious mechanism!
Technology Connections brought me here and now I'm a subscriber. :)
Brilliant and accurate description. I couldn't have done it better myself, and I spent 5 years fixing these things. Great fun.
As a guy who started typing in the sixties, I remember my 7th grade science teacher in 1967 had her own Selectric in the classroom, a wide-carriage green one. Of course, none of us were ever allowed to type on it but I can remember being mesmerized watching her type up mimeo masters, etc., on it at times. Even the school's secretary only had a regular Model C. I was a pro typist through a decade of college, all of it being on Selectric-based word processors (MT/ST, MC I, MC II). I still own two of these (Correcting Selectric and Personal Selectric) and love them.
Great video Bill. Big fan of your channel!
I was a secretary back then and had a wonderful red Selectric. It was beautiful to look at and great to work with. It brings me good memories.
Love the zoom-ins. Great style, suits the presenter / content!
These videos are absolutely incredible
I love these are under creative commons, bill explains things in such a simple and intuitive way
Also used in the "Selectric" article on English Wikipedia.
Clear and succinct explanation of amazing technology!
Hello from Technology Connections!
Technology Connections sent me. Great video!
Cheers!
There was a product sold that was a computer interface to a Selectric. It was actually a solenoid keyboard that attached over the Selectric's keyboard to press the keys. We had one of those attached to a Tandy TRS-80 (trash-80) computer. Thanks for the video.
That's so nifty! No wonder some people get nostalgic about old hardware.
Neat video! I have wondered for years how the ball kind of typewriters work.
Love this stuff!!! Keep up the good work Bill!!
That takes me back. They were state of the art when i learned to type.
My uncle worked for IBM in Office Products in Boston. He kept us in typewriters in the 70's. One day he came and swapped out our Selectric II for a similar product but this one came with its own desk and a console to sit next to it. But sitting on/in the desk was a mostly normal looking Selectric. But this was no normal Selectric. This was an MT/ST which stood for Magnetic Tape/Selectric Typewriter. This rig could read and write to 1" Magnetic tape drive that resided in the console! This was a word processor! You could store a document code at the start of your document and later search a tape for that code to find your document then insert a new piece of paper and press PLAY. This is when you could witness the Selectric operating in its glory laying down characters at maximum speed and maximum decibels! The console was something of a marvel also as it was invented prior to integrated circuits. It had a huge array of relays and a row of printed circuit boards with transistors, resistors, capacitors and such. Inside the top of the console was the dual 1" tape drives. This was classic IBM mechanicals with heavy gears, clutches, cams and motors. At 8-10 years old I loved watching the read/write head moving back and forth across the tape and the mechanism advance the tape character at a time as I typed. Backspace moved the tape back one character. Later I went to work at IBM in service and the old timers didn't quite know what to make of all my experiences with 1960's and 70's hardware when I was 28. My uncle continued my education through the intro of the IBM PC. I learned to setup , configure, upgrade and diagnose those machines when I was 12. I credit the MT/ST and my uncle with the development of my technical mind.
Thanks to the Stuff You Should Know podcast with Josh and Chuck fir sending me here. New subscriber!
A whiffletree mechanism was also used to position the head carriage on the old Univac FASTRAND drum units. Basically, the WT levers were operated by solenoids that pulled on the various levers. A direct binary-to-analog motion converter.
Thank you for introducing me to the Selectric and the Whiffletree
Im still amazed this was created back in that era. This thing is way ahead of its time.
Fascinated by how this works, and trying to dive into more deep detail on how it was accomplished. This video just scratches the surface, though. How's it look like in the machine, in operation? How's the keyboard interface with those levers? Ahh! I just have more questions now after watching, and my search continues. Still, a good start.
yeah! I want to learn more about how this level of accuracy is sustained I'm sure after a minimum of a crazy number of keystrokes expected in its lifetime!
The mechanism that moves the type font plate (containing a number of 5x7 dot matrix patterns interleaved in a single grid) in an old IBM printing keypunch (026 or 029) is also a fascinating piece of mechanical engineering. Its input is the motion of the punch bits selected by the keyboard (or duplicated from the card most recently punched), and its output is the motion of the font plate up or down and left or right a few increments, before a hammer strikes the back of the font plate to hit the wide ends of some pattern of 35 wires at the wide end of a curved funnel. The narrow end of the funnel hits the ribbon and card in the area above the column being punched. I’d love to see a video on how that mechanism works.
Very interesting. We had these at work. Called them golf ball machines. Ingenious. I moved up to a data processing machine, a magnetic card machine, which was very similar but with a huge floor standing memory with very thick connecting cable. I was the only one in the UK government department at the time. No need to retype reports as the magnetic card held all the typing in its memory so just had to stop the machine and correct the reports. Brilliant at the time. I’ve never seen nor heard of them since.
Wish you could show us the rotation as well... Great content. Very few videos on UA-cam today have such a great content.
“Whiffletree” is absolutely my favourite word now.
Just follewed through to this from an article on Hackaday. It brought back memories of our Selectric back in the 70s, and what an incredible piece of engineering it was. My dad worked for IBM and we also had a scrapped Selectric I/O Writer which had a bunch of tilt/rotate solenoids underneath the main Selectric chassis. We had intended to get it working with our 'home microcomputer' back in 1979 (a Fairchild F-8 3850 kit) but never did get far with the interface logic unfortunately.
You still here?
Technology Connections sent me here. Great video!
Born in 1980, I grew up around these. At 8-10 years old, I can recall being absolutely amazed by the mechanical marvel of the IBM Selectric. Whereas the traditional typewriter (a finely crafted instrument in its own right) had a simple enough design for a 9 year old to comprehend, the Selectric seemed like straight up wizardry to me. Yeah, I grew up to be a mechanical engineer...
My regards form... THE FUTURE!
Really miss this channel though the Technological Connections channel is doing it's best to pick up the slack.
10 years later still been a good video
wow, super awesome the way you broke this down.
Very cool...the Selectric was definitely an overlooked engineering marvel and as I recall the same technology was also used as the "console" of some of the first interactive IBM computer programs of the time. It got me thinking about my early days and made me wonder, have you ever done a video on how a slide rule works? I was in undergrad Engineering College in '75 and the TI calculators were already in use by almost everyone but some of the Profs still required we use slide rules in the beginning of the course work...my Thermodynamics Prof required them throughout almost the entire course, though he allowed the TI to validate our answers (a recently retired multi degreed Engineer with Lockheed Martin.
I miss this channel so much!
I learned to type when I was about 10 years old. Shortly afterwards I saw one of these and I was fascinated and I wanted one. I still am, and do, 40 years later
I am repairing an IBM Selcetric ball typewriter in Korea, but Ball's dynamic motion feels like an array of planets in outer space, I recommend that the IBM Ball Typewriter is one of the greatest masterpieces on earth.
In high school I used an IBM Selectric Typewriter. Now I know hot it works. Very cool.
you guys are really awesome.. just a few months ago i learned about the khanacademy videos and now i can watch all this for free too! thanks for keeping knowledge free. i learn more from the internet everyday that i ever did when i was in school!
Wow. I remember typing on a Selectric in college and before that saving my money to by a Brothers typewriter. Well done!
Thank god man. I was looking for how that damn ball got it's ink and the IBM commercial and another video didn't make it clear. Soon as I saw this channel I was much less aggravated.
Fantastic as usual!
This is a machine that never ceases to amaze. Other than routine maintenance, I'd say it's as reliable as a modern day word processing application.
I remember early printers were indeed hooked up to devices like this - digital signal from the computer directly turned into printing.
Later the "Dot Matrix Printers" became dominant of course, replaced by lowering cost ink/laserjet ones.
Hello from channel Technology Connections :) He recommended and linked your video as a much more in depth explantion on how this works then what he could do for his video :)