Teardown of a 50-Year-Old Modem | Hacker News Reader

Teardown of a 50-Year-Old Modem

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Steve Garcia in BYTE (1983) had a DIY acoustically coupled modem ($20 in parts )

I was (in the UK) sorely tempted to change a couple of components and get our electronics shop to build a batch for a project we where doing to avoid the huge GPO tax £300 for answer and £650 for answer origionate.

All Illegal of course - though that didn't stop us hacking the modems we did buy to have variable gain.

For information we brought 6 modems (more than my salary at the time)

Steve Ciarcia?

He wrote the hardware column in Byte magazine for years. He wrote articles about making just about anything hardware related, from video cards, to printer spoolers (dedicated computer to accept a print job from a general purpose computer and dole it out to the printer), to modems, to simple computers running BASIC (think the forerunner of the Raspberry Pi).

I think the poster was pointing out the misspelling of his name in the original comment. He's Steve Ciarcia not Garcia.

Oops my Bad apologies to Steve Ciarcia

UK 1976 I was doing a computer science O level at the local technical college (Wednesday afternoon release from my school). There was a 19" rack modem with accoustic coupler on the front and a dial to dial the number. That was connected to a teletypewriter. We did some BASIC 'interactive' programming (the main projects used coding sheets).

The system was vulnerable to thunder storms I remember (line noise). All good fun.

I rember my first Job (based at Cranfield Uni) and we where a long way away from the Exchange - Some times you had to whistle into the acoustic coupler to get the carrier to pickup then quickly put the hand set in.

I wonder why the acoustic coupler was removed?

Eyeballing the pictures there is a lot of corrosion in there. It would probably be difficult to bring this guy back to life, and even if you did it's probably 300 baud or so.

300 would be quite amazing out of that. More like 75/75 for TTY connection.

Probably frankensteining together a fixed thing out of a flaky modem and a better modem where something bad happened to the coupler.

This makes me miss good swap meets. The MIT Swap has just been guys in vans selling plastic trash for the last couple years.

Look at the big transformer, I was thinking "audio", and sure enough, it's an acoustic coupled modem, as in "set the phone on the modem"

https://en.wikipedia.org/wiki/Acoustic_coupler

If you are referring to the large transformer clearly visible in the first photo at the top, that is most likely the AC mains transformer that supplies power to the modem. This device would have been built before the days of switching power supplies, and linear power supplies (esp. 50 year old ones) often begin with a step down transformer of about that size

Guessing this board is the bridge rectifier and DC voltage divider that comes right after the transformer: https://hackadaycom.files.wordpress.com/2019/03/pwr2.jpg

That was my guess as well, given the four diodes on the right edge.

Don't modern amps also have coil transformers?

A tiny bit misleading: yes it was a teardown, but I was hoping we'd see a discussion of the circuits, like the guy that built the analog video game console a few weeks ago. Still cool tho.

Only saw coupler in books and in war games the movie. Use digital modem Hayes command etc already. Sad he did not do it. Nice to see how it works.

The modem itself is certainly interesting but the author's tone is very condescending. Who is Hackaday's target audience, anyway?

Nerds. Who think they're smarter than everyone else. It's like Hacker News. The tone really fits the audience well.

Not Fortnite players, apparently.

I tried to find a condescending remark. What did you find condescending about this article?

I also gave that comment the benefit of the doubt before I actually looked at the article.

"Very condescending" is a stretch. The most suspect thing I could find was the "fortnite" comment. It's a throwaway joke that won't amuse everyone.

The paragraph that began "The probability of knowing what an acoustically coupled modem looks like is inversely proportional..." did read (to me) as condescending - but I think we should be generous and assume the author did not intended it to be.

It set the tone that you read in your head, but the rest of the article is fine (and really interesting!) if you can ignore that first paragraph and read it in a neutral tone.

I skipped this part and read the rest, I felt zero condescencion whatsoever. I guess that's something you guys cannot grasp.

(NB: some voluntary sarcasm has been inserted above)

It's more that author's particular style than it is all of Hackaday. Most (all?) of the other Hackaday writers do not have the same tone and some are absolutely delightful to read!

I think it is possible that you are "hearing" a condescending tone where none is intended. I don't know the author, and they would be the best to address it (and I haven't finished the article yet), but here are my thoughts...

He's talking about VERY old technology. The older the tech is (and the more obsolete), the more likely it is that younger people won't even know what it is when they see it. That's not a strike against them, it's just a product of the rarity of the item in modern society.

"Fortnite is most popular among players between the ages of 18 – 24, who account for 63% of all Fortnite players." ( https://www.vertoanalytics.com/chart-week-deep-dive-fortnite... ). So the author is saying -- if you play Fortnite, you are likely to be fairly young, and if you are fairly young, there's a good chance you don't know what an acoustically coupled modem is.

I think that's a reasonable thing to say. Perhaps when I have time to finish the article I'll see something that changes my mind, but at this point I think it is worth giving the author the benefit of the doubt.

One person's condescending is another person's folksy and approachable. I am not sure HN is an appropriate place to discuss an author's writing style.

This article is not typical of hackaday.

"The probability of knowing what an acoustically coupled modem looks like is inversely proportional to knowing what Fortnite is"

I happen to know about both, really. All I can see is a bitter boomer talking down to anyone born from the mid-eighties onward. (The actual article is fine, but that sentence sticks out like a sore thumb and makes the rest seem sour)

I would take that as a joke. But I agree, it does have the elitist tone to it.

"The probability of knowing what an acoustically coupled modem looks like is inversely proportional to knowing what Fortnite is"

...And yet, the author of the article seems to know what both are... paradoxically... <g>

If he's said "inversely proportional to having played Fortnite" then I think he wouldn't have been far off the truth?

Inversely proportional does not mean there is no overlap :)

Excellent Point!

I stand corrected!

>> All I can see is a bitter boomer talking down to anyone born from the mid-eighties onward

Isn't calling the author a bitter boomer the same type of generalization as that sentence you find so offputting?

I'm a Gen X-er, and someone from my generation could have just as easily made the same misguided joke. Acoustic couplers were still quite common when I started using computers in the early 80s. Heck, my high school still used card readers for "data processing" classes right up until the mid-to-late 80s.

Note that the boomer did not say: "anybody who knows what fornite is CERTAINLY does not know what an acoustically coupled modem looks like"

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