this is the console 2624, a hall-effect keyboard that was made all the way back in 1989 in the CSSR, the Czechoslovak Soviet Socialist Republic, using components from Tesla, and it was deployed in places like the Chernobyl nuclear power plant. This thing doesn't glow, does it? Not if we keep the lights on. That's reassuring. I've already got a lot of questions, but the lab made that old Soviet Mouse work. So, I'm guessing the answer to can I game on it is yes. Yeah, you can, and it's one of the best keyboards we've ever tested, but also one of the worst. We'll unpack that in a bit. First, I need a word for what this thing feels like. Wumpy. Here, listen for yourself and listen to the segue to our sponsor next. To say bonjour to the Hello Cam Pro and give your setup an upgrade with its 1080p resolution, 60 FPS frame rate, and Windows Hello facial recognition. You can learn more at the link in the video description.

specimen here is a product of zuco Bruno or Bruno Armory. First founded in 1918, they made everything from rifles to cars to farming equipment, and they have a soccer team named after them now. Anyway, none of that matters for the moment. What matters is getting it working, and I suspect our first problem is going to be this connector they used a game Port. Well, sort of. It's the same da15 connector, but in this case, it's used for simple asynchronous serial Communications. Simple-ish. This helpful post on deskthority keyboard Forum gave us some good pointers, and as it turns out, we only need to hook up six of the pins: ground, serial input and output, both 5 and negative2 volt power, and finally a clock pulse. Does asynchronous cial normally need a clock pulse? No. Ah, so there's your ish. A little more on that later. For now, according to Forum post, we need to provide a square wave at 16 times the frequency or B rate. Okay. Oh, but there's a recommended value. Wow, I can't believe

how easy this is turning out to be. We just wire our connector up to a microcontroller like we did last time. In this case, a Raspberry Pi Pico that we've programmed to send the clock signal using timer upts and then read the serial data and spit it out over USB. Okay, not super familiar with their alphabet, but hey, I know Numbers. One, M, H, two, O, X, UH, okay, V, UH. It's pretty clear something's wrong because if this is how it worked, I'm surprised Chernobyl lasted as long as it did. Time to do some digging. We can see that different Keys produce the same output, but to really understand what's at play here, we're going to need to see the individual bits. And hence you weren't kidding. This is awesome. Rhoden Schwarz has an asky mode that means that not only can we see the raw output, but it actually shows us up at the top exactly which asy character it's supposed to correspond to. Of course, as cool as this is, that doesn't really fix

anything. So, in order to do that, we had to change the mode. What are we looking at now? So, once we showed it all in binary, we could very easily and visually see that the first half of our data was varying as he presses different keys, but the second half was not varying at all. We had to figure out why this was happening. Interesting. So, that's how we compress two different keys and get exactly the same or a similar enough output that we get the same value. That, my friends, is why electronics need to come with schematics. It's like a breath of fresh air, you guys. If this keyboard was a tightly integrated modern device, we'd pretty much be throwing it in the garbage. But thanks to our comrades at Zaba Bruno, we've got this, a complete guide to the inner workings of our keyboard. So, all we need to do is work our way back from the connector to see what's going wrong. This right here is our data output line, and it comes from this green thing right here that is.

a uart chip, which is short for Universal Asynchronous Receiver-Transmitter. In a nutshell, it serializes incoming parallel data and then outputs it at a given frequency. Fun fact, by the way, there was a parallel version of this keyboard, the 2423, that didn't have the uart at all and would have saved us a lot of investigative work because we would have immediately noticed the problem when we read the raw data that half of every byte was locked to one. But why? Well, the input to the uart comes from these two orange IC's right here. These are ROM chips that hold lookup tables. If we trace back one more step, we get to the keyboard controller, which takes its input from a pretty typical keyboard matrix. Now we're all the way back, let's go forward. That matrix gets translated by the keyboard controller into a 9-bit parallel signal and a strobe signal that indicates a key has been pressed. The nine bits go to our ROMs here and get translated into two halves of a single byte, which the uart receives and

then converts to serial. Once it sees the strobe signal, it then sends that to the output. Or at least that's how it's supposed to happen. As it turns out, one of our ROM chips is just broken. Also, wait a second, nine bits. Ah, I'm glad you asked. See, seven bits would give us 128 values, which is enough for a basic ASCII table or whatever kind of ASCII table we're dealing with here. Then there's two bits for the modifiers, which means four values. And that turns out to be no modifier, control, shift, and repeat. Wait, repeat, repeat, repeat, repeat, repeat. Yes, repeat. Okay, guys, that's enough. Sorry, sorry. See, on most modern keyboards, repeating is built in. So when you hold down a key, it registers multiple key presses. But on this one, it's press once, fire once, no matter how long you hold it, unless you also hold the repeat key, the repeat key, the repeat key. We can actually see this in action if I just hold down the key. Takes a second to spool up, but kind of has some

interesting implications for gaming, doesn't it? If only we could get it working. We can, we just need to ignore the parts that don't work. We just need to intercept these signals by wiring in our microcontroller before these broken ROM chips, so they can't mess anything up. We programmed the microcontroller with our own lookup tables based on the documentation we found, and then the microcontroller just acts like a USB HID device. Are we ready now? Of course, we just need the uh, Magnetic Cable Management Arch from LTT store.com. Heck yeah, it helps if you actually put it on the cable. I did the one that we need, this one's useless, fair enough. Oh, why do I have to use the Soviet Mouse too? No, I want a real mouse, maybe later, but right now we need to try it with this. Oh, it's so bad though, the arrow keys are your movement, not W-D. Well, where's anything? Got to look around, there's the arrow keys up there, they're line, they work slowly. What? It works ever so slightly, no.

that's not Zed or X, that's Q. Well, where are Zed and X? You got to look around. Zed, God X, nice. Oh, oh no, oh no. Come on, a little bit too much. So, um, because the keyboard only detects the pressing down, the amount of time that the computer reads that you press the key is set by us. So currently, it's not really reading it very well. Okay, well, why did you do that? I thought it'd be funny. Come on. Okay, can we change it higher? Yes, we can change it. Thank you. Okay, new attempt. Here we go. This is going to be way better, right? Yep. I changed the delay to 50 seconds instead of one 50 Mills. Okay, shoot. That was just user. Okay, this is really unergonomic still, but um, this is totally usable. So, this is just essentially the polling rate that it's set to. It's like how long the computer thinks the key is held down and then let go. So the signals are only sent.

when you like press a key not when you let go like a modern keyboard right. So it's how long I tell the computer I'm pressing it you're pressing a key. I am I don't think this is professional Tetris not very good at Tetris so that's good I thought I was doing bad okay look I am old oh you can't like press multiple things at once though it's very aren't you excited to play an FPS. God no it changing the thing every time I rotate is driving me absolutely crazy okay what what is oh God this mouse. I was like well I'm done with this game alt F there is no alt well there's no F keys there few how does this keyboard work f space is f pay respect to this keyboard why is it not going up you could just use the like arrow keys. I'm going to have to play an FPS game Ariel going to try totally playable see you just got to press it a lot like oh and then it holds it down um wasn't doing this

before uh uh uh C. Where's c c out of fuel um double okay can I have a real Mouse yeah this one right here all. Oh Glory kill e yes yes yes yes yes okay still alive. I'm not close enough come on E yes yes yes still alive oh no wait what can we do with teamwork okay so I'm going to hold the repeat key oh what is going oh right okay so I can't hold the repeat key when you space otherwise you're going to continuously jump oh we got to like let go at the right time yeah okay okay okay there we go get get over there get over come on come on go brother go now you have got to be asking yourself how could we say at the beginning of this video that this is the best of anything as it turns out it is one of the most consistent keyboards that we have ever tested on our robot that is to say that the actuation force and the travel distance is nearly identical from Key Tokey thanks in no

small part to its 80s style solid steel backplane. You got to love it. Of course, if you're not pushing the key straight down right in the center, you're going to have a pretty bad time. Let's just put it this way, key stabilization has come a long way in the last 35 years. You know what else has come a long way? My Segways to our sponsor, manscaped. Step Into Summer with confidence, thanks to manscaped and their performance package 5.0 Ultra. It includes the Lawn Mower 5.0 Ultra groin and body hair trimmer. Turn that overgrown forest into a serene garden. Just don't expect any flowers to start growing there. If they do, please seek help. Also included is the Weed Whacker 2.0 electric nose hair trimmer, so people will actually look you in the eyes when talking to you, rather than into the dark abyss faintly outlined with the tentacles of some long-forgotten eldritch horror. Anyways, you'll also get their Crop Soother aftershave.

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Gaming on the Keyboard from Chernobyl

Linus Tech Tips is a passionate team of "professionally curious" experts in consumer technology and video production who aim to educate and entertain.
