What kind of computer is this?
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- Опубліковано 29 лис 2022
- This was one of those, 'oh, it's got 5 sec left, I'll bid it up five bucks, I won't win, and then I won' situations. It's a Z80 single board computer, it just arrived, so here is some raw footage of me messing about with it. This is the kind of surface level exploratory stuff I do with incoming vintage gear, especially homebrew stuff like this. What did the builder intend for this? Sadly the EPROM appears to be pooched. I'll post the garbled code below - let me know if you recognize anything in it!
° Dumped EPROM here: drive.google.com/file/d/1wgFW...
° Pictures of this machine here:
drive.google.com/drive/folder...
° durgadas311 has started a github project on this machine to reverse engineer it (thank you durgadas311!!!):
github.com/durgadas311/homebrew3
° Background music provided by:
www.epidemicsound.com
° I'm on Twitter - rarely.
/ techtimetravel
° I've a Facebook page too - I guess?
/ thetechtimetraveller
° Hangout/tip jar.
/ techtimetraveller - Наука та технологія
For those interested I have added two additional links - high res photos of the board as well as a link to a github project a very helpful user on vcfed started to help reverse engineer this machine.
The link below is important information regarding wifi connection if you can Understand or translate for yourselfs I did make comments however I don’t speak that language and did not use a translation assist. Let me know what you think.
ua-cam.com/video/doG3bLX6_x4/v-deo.html
My first guess is that this would have been used to connect over the phone line to some service that was generating a data stream, possibly a news ticker or weather sensor or something generating financial data, and once connected it would have sent that data to a printer, creating a constant data log that could have been checked later. Maybe for logging meteorological data, or some other application, where you had had a remote sensor system connected by a phone line and wanted to have a hard copy of the data it was generating.
Alternately, it could be a homemade wardialer. The keypad and 8 digit display would be used to enter the range of phone numbers to sweep over, and anytime it found one that had a modem connection it would print it out on the attached printer. You'd set it to run overnight and then just see what numbers it found on the printout in the morning.
I was thinking a wardialer, too. I really hope it is, that would be so cool!
One thing I thought of for its purpose is that the keypad being on that long of a wire could mean it might have been outside a door or around the corner as an access device. Then it would control something on that 50-pin header. The other serial port would connect to a terminal, maybe for debugging. That would mean this wasn't just some toy to program for fun, it was actually being used for something!
The display flash was probably a power-on glitch that the display itself quickly cleared on reset.
You have to be early GenX to remember those phone connectors, as they basically vanished by 1980 or so as RJ-11 was quickly adopted. The Carterfone decision was in 1968, and customer-owned phones needed a better connector.
That was my first thought as well.
Based on the age of the chips in the keypad, I wouldn't be surprised if the controller was originally all TTL.
Heck, I'm older Millennial, and I _barely_ remember those jacks. They were obsolete years before I was born, so I only saw the occasional rare one in an older house -- either with a similarly old phone plugged in, or nothing at all. And I saw the occasional adapter plug in a junk drawer. _EDIT: Or on the rack at a hardware store; I think you can still get them, too._
As for the computer and keypad, as interesting device all around.
Before I even watch this, I just want to say by the title alone that you have the most understanding wife in the world. She's amazing. My wife is like that, they are a rare kind imho when it comes to this so treasure her.
Yes. And if I should suddenly disappear... 😆
I'm sure that your viewers will remember you fondly when a flood of vintage hardware suddenly appears on the market here in Canada.
@@TechTimeTraveller Haha, no worries. If after some old homebrewed electronics sold on ebay, and your wife suddenly puts out a message that you got bored of it and stopped making video's then rest assured... I won't believe it and will look for the body. ;)
9:56 Those four switches make me think of serial communications: the 4800 / 9600 switch for baud rate, and the other three for number of data bits (8 or 7), parity (None or Even), stop bits (1 or 2). But... 9600 baud wasn't in use in telephone modems until the early 90's, so that can't be it. Maybe those were serial port settings for the computer it was attached to?
I was thinking that's for a terminal.
I was born in 79 and yea we had some 4 post phone jacks in our house growing up, my dad would replace them as needed with RJ's. The only place I ever saw them with a phone plugged in was at my grandparents house
I'm old enough to remember when the 4 post jacks were the only game in town! The second set of two posts is used to light princess phone dials via a 24v plug-in transformer that was usually located in the basement.
Very similar to my late 80's / early 90's tech college CPU board. That was wire-wrap, too (which is fantastic for a hobbyist, btw! I wish it was still a popular thing. With a day or two of practice, you'd be making circuits as fast as breadboarding. And shockingly reliable, which you can't claim for breadboarding. After a few weeks, wire-wrap connections apparently self-weld). I still have my 6809 board (amazing processor!), and it still works just fine despite being knocked around in a drawer. Even the modem "works", but I don't have a landline anymore, and no BBS's to call.
I once designed a very similar board for controlling a Qume Sprint 3 daisywheel printer. The interface to the printer was 50 pin ribbon cable, like your board has - everything is there for that. AZ80 PIO would fill the bill. Z80 CTC for baudrate and SIO UART. Pretty fancy parts.
The ls138 and ls139, perhaps with a couple of gates for address decode. Among other things, the ls14 for reset generation. The S163 serves to divide the 20MHz down to the max clock of 2.5 MHz, in part, anyway. At least that is my recollection of Z80 (not Z80A).
Qume! There is a name I haven’t heard in decades! My poor Dad spent the equivalent today of $3000 on a Qume daisy wheel printer for me when I was a kid.
The Z80A is identical to the Z80 except they bumped the max clock rate up to 4 MHz (instead of 2.5 MHz for the original Z80). The NEC D780C is also a Z80A CPU clone with a max clock of 4 MHz, so that's consistent with the other "Z80A" devices on the board.
Though if they were using one of the outputs from the 74LS163 to divide it down, as you suggest, 20 MHz / 8 = 2.5 MHz, so it's quite possible that's what they're running it at, even though all of the chips could actually go faster...
For testing old equipment a cheap current limited bench power supply is a very useful thing. ~$50 in the US. Not only for protecting against shorts but for seeing if anything is drawing power at all.
I've got one on order. Was thinking about setting up an acrylic bending element with one.
It reminds me of my senior year micro project in the mid eighties. Switches for single step/run, code entry, and such. All our projects back then were wire wrap.
If you can check how the data and address lines are wired, someone may have hooked the rom data lines up in a way that it looks gibberish but the cpu reads fine and burnt the eprom to compensate
clever!
I've seen hundreds installed all over the country... I'm only in my 60s. They are still in use and working fine in older homes!
What is it?
the phone company replaced those with the modern ones when we got the 7th digit in like 78 I think after that we got the "traditional" rj plug.
I forget we didn't always have 7 digits.. interesting!
My first thought was "that poor uncovered EPROM can't have any data left on it, can it?"
I see so many vintage machines where they don't cover the windows. Seems to be a thing.
@@TechTimeTraveller EPROM's can only be erased with short wave UV, like what is produced by a germicidal lamp.
I used a lot of them back in the early '80's and was concerned about having my programs accidentally erased so did a test. Direct exposure to Texas summer sunlight for an entire month didn't change a single bit in the image, so I never worried about it again.
I remember those big phone jacks. My parents house was new construction in 1975 and had them.
The RJ 11 and the DTMF keys make me think it was designed to be hooked up to a phone line. But it's not a "phone phreak" device--those were much smaller and simpler (and would fit into those Radio Shack blue plastic speaker cases somewhat smaller than a transistor radio). And so-called "blue boxes" needed three buttons in addition to the numbers (and no chips).
From what i can see the Eprom has:
-somthing with multipel Paralel Ports
-a lot of Octal stuff
-some expansion Slot like
It olso might not boot without the keypad
Terminal Node Controller TNC? A packet radio modem for HAM use? Some commercial units had the same LED bar. Or its just a normal modem with a pulse dialer.
Just looked it up packet radio started about 1973 So it could be.
If I can believe my eyes, the date codes on the Keypad ICs are early 1971! These chips must've cost a pretty penny back in the day.
(and I spotted a 7493, so that's a 4 bit counter, so the keypad has more smarts to it than it looks. And so does the LED thingy, like why would an LED need 7 or more wires?)
And wow at the colorful wire-wrapping going on. I was working at a small-scale manufacturing company (3 people including me) as a college job and we had four colors of wire-wrap. And the red one was almost unusable (it broke where it shouldn't and didn't break where it should). And the yellow one was 20 years old and I was supposed to stay off it.
Yeah they're even back to 1970. Possibly earlier. I feel like that board was built early.. although it's possible they're just parts from a drawer years later. But given they're all in that range whereas the computer is 1977 or later, I don't think so.
@@TechTimeTraveller [senilyDeluxe] starts to drool uncontrollably.
My money's on that being an LED bubble display on the keyboard, consistent with the number of wires.
The board under the keyboard looks most interesting to my eyes. It would be nice to have a close look at what ICs are there on the board.
This one is way over my head but I am looking forward to you sussing out what it is for!
Ha! I was planning on bidding on that lot but the price got too high and I thought that it seemed more like bits and pieces of an electronic hobbyist's workshop as opposed to an actually system. Still cool!
P.S.- My "ha" was just me saying "ha, I know that lot! 😁"
That's a bummer that the eprom didn't have anything helpful on it, I remember thinking when I saw this lot that it was good that there was an eprom since it would probably help unravel the mystery of these pieces.
On keyboard enthusiasts stripping retro tech for keyswitches: A responsible tinkerer would never strip a working device for parts, but more and more often sellers are deciding it's not worth testing retro tech (due to missing PSUs, cables, boot media or appropriate IO devices) and are instead selling any old electronics as "untested". Which means someone looking for specific keyswitches, or an interesting enclosure for a case mod or a specific rare CRT now can't even responsibly buy "broken" electronics without risking destroying a functional antique, unless it's super-obviously broken beyond reasonable repair, but in a way that happens to leave the desired parts intact.
Born in 73. I've never seen that style phone jack in use, just in junk drawers and hardware stores. My house and parents house was built in the early 50s and have rj11. I have my parents rotary phone that they got when they moved in to their house in the late 60s it has an RJ11 connector.
I don't know if this is what it was doing but in the 70s and 80s some people sent RS-232 over telephone wires and telephone jacks to distant terminals and printers. You only need three or four wires and you could get 20 feet of the stuff at Radio Shack for cheap, much cheaper than using a proper 25 wire cable.
I don't always buy sketchy electronics online. But when I do I call myself tech time traveller's.
🤣 but in all seriousness, love the content. Thank you for keeping this beautiful contraption in the lime light.
I think you've got yourself a fax machine here though.
Print from buffer and dial/send via buffer.
It kinda reminds me of an OLD OLD Panasonic dot matrix printer controlled access system. Essentially you would send a print job to the printer to print something, but it would stay in memory on the board until a code was entered. This was 20+ yrs ago when I saw it but kinda reminds me of it. It was used in like copy rooms at schools. I'm probably wrong and my memory foggy, but who knows.
We had something like that when I was in University. We had to enter a code to release the print job, and it would then be charged to our account. This was in the late-1990s. I do not recall the details of the hardware (even though maintaining it was part of my job as computer lab TA), but I know that it was old and due for replacement at that time.
I think what that is is one of those old school “blue boxes” that gave you free long distance
A childhood friend had crates of old (50-60s) keypads from phone and coms exchanges. His Dad used to buy (and hoard) all sorts of electronic junk from liquidation auctions.
I have a love/hate relationship with the keyboard guys. I hate when I see something for sale that CLEARLY was complete, now missing the unobtanium keyboard because a keyboard guy got it and didn't have the heart to throw away the "useless" system. On the other hand, I've had a few total mystery stand-alone keyboards that nobody on vcfed or elsewhere could identify at all, that I was able to sell EASILY for way too much money and recoup sometimes what I had just spent on an entire haul of systems. Ya win some, ya lose some.
Id like to see an hour and 45 minute video on a review of the keyboard where he just roasts the people who invented it who are long since dead.
@@pikadroo You might be interested in checking out Chyrosran22's channel then!
Oh hey. The house I grew up in had one of those phone jacks. I didn't recognize the plug, but as soon as you said it was for a phone, I remembered the one weird circular phone jack behind the record player that didn't get replaced because that wasn't where we kept the phone in that room anyway.
WOW THAT HANDWORK 💜
This thing has struck my curiosity bone hard ... few ideas of what it may have been and i see others in the comments have said what i thought it may be ... darn interesting to say the least mate. Cheers.
You mentioned you eventually want to learn micro programming. Well, I would absolutely have to recommend Ben Eaters 6502 series on his channel, which starts at the hardware level and eases into assembly in the most natural progression I've ever seen for any lecture.
Ben is such a blessing to the community.
Im addicted to picking up electronic stuff like this too. Always thinking I can fix it or if not tear it down for the parts!!!!
I wonder if this is an early version of those fancy phone "phreaking" boxes that enabled you to basically call for free and/or do some other naughty things with analogue pulse/tone landlines :) Seems like one for all I know (which ain't much as never had the "pleasure" of seeing one in action although my mother would have appreciated in the early BBS days as I did rank our phone bill a couple times with my 2.4Kbps modem)
Hey, yeah! I thinking some kind of auto dialer. Some thing about it made me think that.
There's a phone in my grandparent's house that still has that ancient connector. Too bad they're both gone, glad the house is staying in the family.
"oh ill save a few haiil marries before i plug that in" this dudes Irish Canadian folks, we have a bad ass on our hands
shots fired at the mechanical keyboard crowd😂
Holy mega perfboard batman!
Its kinda beautiful in a retro kind of way. Before my time, but awesome none the less.
My guess would be that the keypad is BCD or possibly ASCII encoded sending over a serial connection. Using modular telco connectors wasn't unusual in the 70s and early 80s due to the low cost and relative obscurity/unavailability of the more modern DB-style connectors.
The 50-pin IDC connector and the general layout makes me think that maybe this was a debugging system for, or perhaps some attempt to expand the capabilities of, some other system that your board interfaces with via the 50-pin.
I have a 4-pin phone wall jack in one room of my house. It has an adapter to RJ socket plugged into it all the time. As far as I can tell the jack and adapter are very close in vintage, so it probably got installed just as RJ connectors became ubiquitous. All other rooms have RJ wall jacks.
I probably wouldn't get too hung up with the phone connectors. They were probably just the easiest and cheapest to get hold of, and maybe just made use of a spare pair of wires around a house or office building?
At the very least there doesn't seem to be enough hardware for a modem on board (or there is zero isolation circuitry which would be a hazard...), unless it hooked up via a serial port to an external modern.
It looks like all of the A and B port signals from both of the PIOs go to that 50 way connector. So there's a lot of IO going there - upwards of 32 bits.
Could be for a printer, or it could be lots of inputs and outputs for controlling relays etc (via some other driver boards). So maybe some kind of crude IO controller, like a light sequencer or something.
Great video ! What a mystery . x
EPROM programmer maybe ?
1:15 my high school still has one of those, I doubt it is still wired in
it was still in use in the 1980's, according to one of my teachers that was a student back then
they had a terminal plugged into it to dial into a mainframe at the college a couple towns over. I wonder if they still have it?
All those telepone wires tend to look like that. When fixed to a wall, people tend to paint their houses and they paint the wires as well.
Fascinating archaeology.
I do remember that 4 pin phone jack when I was young, we had an old rotary dial telephone that used that plug. I think that telephone was from the 1960's and we need a adapter to an RJ 11 to keep using that phone which I do remember weight a ton
Whatever it is it was certainly a better buy than my latest project. I bought a high end office printer from 2009.
434 pounds without toner, drums, or paper. only took 4 people to load into my truck and only broke 2 dollies getting it into the house!
Oki CX3641 MFP if you have interest.
Ok I'm interested.. why? 😀
@@TechTimeTraveller It's always been a dream of mine to own a large format office printer. Weird dream, I know, but I actually want one larger than this. Yknow the old Xerox 9000 series you could use as a counter top if you wanted? I want something like that. I think they're interesting.
@@AiOinc1 Kind of reminds me of when I got an original HP Laserjet (the very first model) for $40 from a computer store. It weighed a ton, sounded like a Mack Truck and needed those font carts to print stuff. Wish I'd kept it though.. you don't see them anymore.
@@TechTimeTraveller This was $50 and came from a local thrift store I frequent. If it wasn't obvious, this type of thing is why I frequent their store, haha.
Along with the hard disk drives I mentioned in another post, I have a small collection of unusual printers as well, including the original IBM ProPrinter, a souped-up LaserJet 2420d, several dot matrix printers, a Royal LetterMaster, a Sweet-P 6 pen plotter, etc. And now this as well!
@@AiOinc1 Proprinter is one I remember. Do you actually get much use out of them? I've had opportunities on some vintage printers over the years but I always shy away because I can't think of a semi practical use for them. So they take up space my computers could fill. :)
My first guess is an access control system keypad you'd set up outside a door, with the board somewhere else doing logging. It has the vibe of something Steve Ciarcia might rig up in his old "Circuit Cellar" columns.
nope it is a modem - the question is what kind of connector is at the side - mabe a selfmade fax or sparepart for one build by engeneer.
My first guess is a modem. A direct wire digital modem. The 50-pin probably is a connection for an 8-bit or early 16 pin pre-ISA backplane bus. Such as the SWTPC's SS-50 bus backplane.
The cable sheathing discoloration was extremely common with the low-budget the telcos would use. Those large 4-pin phone conectors were in use in Alaska through the mid 1970's - the duplex I spent elementary in was built in 1975 prewired with 4-pin jacks.
Note also: Telephone 4-wire includes a low power (48v unladen, 9v laden, 20 mA, DC, but only 4v 20mA is a safe assumption) and a return. Phones needing more need external power supplies.
Wkipedia SS-50 en.wikipedia.org/wiki/SS-50_bus
Yeah Im thinking modem too. Dial pad with DTMF or Pulse dialing? Not sure on the standards at the time in the US. Baud rate selection and that 50 pin connector, as you say, some 8 bit data bus to whatever computer this was linked to. Love this kind of homebrew stuff.
My rotary phones still have those modular jacks
Ok, complicated but excelent video, i have a few stranged machines
im 33 and the connecter you show in the beginning was pretty standard in europe lots of phones kept using that. You could even stack multiple.
I think this was an teletypewriter interface it would hook up to a computer and the teletypewriter would input and output. If I remember correctly the teletypewriter would hookup to the telephone line’s. Back in high school in 1970’s we had something like this in electronics class.
Saved from vultures. Very good.
Separate +/-12V supplies for serial seem like such a luxury if you know your analog tricks. Anything with a transformer that can output rectified DC that regulates down to 5V can also output more than enough AC to get 6-7VAC (usually way more than that) and with a diode doubler/inverter get it up to +/-12V. It’s interesting how many of those older digital designs really struggle with anything analog beyond a basic linear regulator. Of course I can’t say much about this one, since the supply wires might have as well gone to a box that did use just a single secondary transformer. So the foregoing is just an aside prompted by this vid.
What caught my eye was the electronics in the keyboard box appear to be from 1971 while the electronics on the "main" board date from 1981 (with a few 1986 chips as well. Replacements?). So an attempt to automate an older piece of hardware? Notice the keyboad box has no processor, that would make sense given that an 8080 from around 1975 cost about $300.
As for the phone jack, this setup dates from the days that the phone company didn't allow you to do your own wiring in the USA. They also could tell if you had added a phone by looking at the impedance to your house.
Without watching more of the video prior to commenting the indicator light is to identify rather it is grounded and protected from mis circuit I’d assume
I've just been looking at the code from the EPROM, It is intact with no stuck bits. Otherwise I would not be seeing a 0 and a 255. I'm not sure what it does, but it needs to be located at memory address 0 to run.
I think it is a phone with a Calling Line Identification. My dad used to produce these in early 90s. Yes, it was based on Z80 CPU. Also there is possibly a voice realisation to spell an income call number.
I heard from somewhere online that using diodes on the power supply inputs of the EPROM (I think?) might allow for marginally-there/working from code to be read better?
Yes someone mentioned that to me - dialing down the voltage or something? I was trying to figure out if my GQ-4x4 programmer software could do that.
@@TechTimeTraveller that worked for me when I fried the VCC line on an EPROM. I did 2 reads, each with a different bit tied to power.
Those jacks with the 4 pins were THE first jacks (late 1960s)! Before then, phones were hard-wired!
Those keyboard people scare me, they will do reviews on stabilizer bar lube and 37 different kinds of key switches
Everybody's got their passions. I watch chyrosran22's videos and admit I dig his ASMR style. I don't quite get the fascination with switches etc.. or why people spend almost two grand for an IBM beamspring.. to each their own tho. My only beef with them is orphaning vintage gear that could still be used.
@@TechTimeTravellerI have a number of more modern mechanical keyboards. I use them mostly because they have a better typing experience versus the cheap rubber dome keyboards most people use. I agree with you that buying an antique terminal or system to take the switches is ridiculous, especially if the terminal or computer works or could be made to work...
My best guess: it's a modem for paralel port. Circuit in keypad is for coding the pulse of phone line. 4800 and 9600 for bauds. Reset and start dialup data, other switch for parities.
Maybe keypad is a DTMF encoder for the phone line ? Probably +5VDC +12V -12V for Full RS232 comms not TTL level. Maybe the 50 pin connector is just for expansion using the designers own standard. Bet the buss lines are brought out there. That dot matrix led display is big bucks and requires some I/O to control. The PIO chip probably controls the display. CTC chip probably generates the BAUD rate for the UART chip or SIO chip. Maybe the phone jack has nothing to do with a phone. Just a convenient way to connect RS232 rather than using a DB25 connector. Upper right looks like maybe a "DATA" display that would put the contents of the data bus on led displays maybe some 74LS373 or 374 latch chips there? Maybe used before the HP display was installed. Like the old ELF had Address and Data displays with Til 311 Hex displays.
Post a HI RES picture of the chips. Is there a 74ls138 on board for address decoding ?
That kind of computer is the best to actually learn how to be a good programmer.
I remember the phone jack that had a filter that had to removed to get dial up to work.
It looks like a terminal / modem. My guess is that since the keypad connects to the phone line that it is producing DTMF to dial phone numbers. Seems the keypad is a modem with a built in keypad, amazing for the time!
One " OLD " trick I was taught in an old book was to replicate your code when programming into a bigger EPROM just in case the select lines and address do not match properly. In other words, it will be correct incase the ' wrong ROM block ' was selected and not set to FF or 00 in the unused space. It also recommended filling in the rest of the address space to the nearest full address with NOP.
Wild guess: keypad entry security system using phoneline to connect to computer board to control various locks.
Dude you purchased a calculator. AKA the num pad. LOL. Oh, I have seen those in houses and at thrift sores for the jack. In the early radio shack catalog had an adapter for the phones. Though I talked to the phone guys and they just replaced it with a modern cable. I'm thinking you can add a dumb terminal too it. Oh, I wonder if the keypad dials the numbers for you. Besides just program the display. Very nice.
It kinda reminds me of a steve ciarcia “zap” computer from his book “how to build a z80 computer”… been ages since I cracked that book though 😂 really interesting video though!
Hrmm.... if A8 is stuck, you should still have a collection of valid 256 bit 'slices' of code, just out of context and with a mystery starting point.
I remember the 4 pin Bell jacks. My grandma had sockets that allowed her to move her one piece handset/base - Swedish design (Ericofon?).
The EPROM contents from 00-FF is duplicated at 100-1FF but is different starting at 200 so I don't think the address bit A8 is bad. The box with the numbered buttons looks like it could be (or is meant to be) used to dial a telephone number.
No, A8 is stuck low. 200-2FF will be identical to 300-3FF (not shown).
@6:28 Holy bodge, Batman
buzz door gate entry diy for a gated community
Its a blue box. The ,8 digt display would show the number to be dialed. Blue box's are used to get free long distance calls quite the cool gadget you have found! To bad it doesn't work
At 7:35 the label on the power transformer reads 12.6V 1.2A which suggests this device's original intention was a filament heater for a tube device. I think the indicator on the top may be a 7 segment LED display.
My guess is a custom programmer for a commerical sign, like a large LED matrix display.
I only ever saw that 4-pin connector at Radio Shack. They sold the 4-pin to RJ11(/12?) adapter also.
Maybe an infrared camera could read the label ?
Ooh.. I have one too. Thanks! Gonna try that..
Auto-patch (land line telephony) controller for a 2m amateur repeater? It must have something to do with telephony, and the display is large enough to hold a local telco number.
Hey tech time traveller... the youtube channel SHANGO066 recently came across an old home built computer and he was talking about throwing it in the trash. It has an old ceramic Z80 I belive. If you want I can get you the time stamp of the video and maybe you can hit him up. He also found a ton of IC's too.
For sure! Always interested in homebrew stuff!
Some kind of alarm system.
I reckon it's a homebrew alarm system
I have never seen those phone connectors in real life, but recognize it by the Radio Shack catalog and treating it as an electronics bible for a preteen.
Glad to see someone else is also annoyed by the trend of mechanical keyboard collectors parting out vintage terminals
I try not to begrudge them too much.. we all have our hobbies. I just wish at a minimum they'd try to keep components together in case. It sucks when a rare Data General terminal comes up and oops no keyboard because people are obsessed with blue keys..
i wander if this diy device is some kind of computer connected/controlled auto dialer? maybe a custom modem?
Imagine its just a really weird over engineered calculator.
I remember those phone jacks
Very cool vintage device. It really could be just about anything. Maybe some kind of test equipment for manufacturing? Or maybe just a homebrew computer put together by a skilled and patient hobbyist? Too bad that paper label is no longer legible. Are there 2 microprocessors? the NEC D780C and the Zilog Z-80A?
the 5x7 VFD screen is from an old Motorola bag phone. I have one here ;-)
It's actually a LED display, 8 characters with 5x7 dot matrix, made by Hewlett Packard. At around 25:54 you can make out the HP logo. These were expensive parts, but often used in industrial applications around 1980 or so. Other chips on that board are also from the early 80s. The date code on the display (1987) makes it one of the newest parts in the whole thing.
That's a common coordinator time adjustment keypad......you want that during travel to be able to pop back into their dimension on land per say but it's actually tuning our frequency to match their time frequency like precise gravity used to merge
Well well well, it looks like an old tele-modem system homebrewed by an enthusiasts.
You gonna summon a demon.... good luck!
MILF chip, you say? I'm enjoying all the uploads, Sol project or otherwise. Great as always.
Not likely to interface with telecom line such as a modem would. No line isolation transformer
I think the keypad is a manual dual tone dialer for making outgoing modem calls. You punch in the call recipient phone number with the keypad to make an outgoing call. Alternatively you could use a landline phone to dial as well. This was before the age of the smart modems becoming very popular, Hayes modem dialing sequence: ATDT.... (AT for attention, DT for waiting for dial tone)
DT doesn't make it wait for dial tone, DT means to dial using tones, as opposed to DP which dials using pulse. It's been quite a few years since I've done anything at all with AT commands, but if I remember correctly, waiting for dialtone or not was set in the init string, not in the dial string.
@@eric_d Good👍 It has been so long ago but I do remember that DP is for dial pulse.