modem

64 Articles

It’s Spreadsheets All The Way Down For This 80s Handheld

September 5, 2024 by 9 Comments

Unlike the today’s consumer computer market, the 1980s were the wild west in comparison. There were all kinds of different, incompatible operating systems, hardware, and programs, all competing against one another, and with essentially no networking to tie everything together. Some of these products were incredibly niche as well, only running one program or having a limited use case to keep costs down. Such was the Convergent WorkSlate, a computer that ran only a spreadsheet with any programs also needing to be built into a spreadsheet.

Upon booting the device, the user is presented with a fairly recognizable blank spreadsheet, albeit with a now-dated LCD display (lacking a backlight) and a bespoke keyboard and cursor that wouldn’t have allowed for easy touch typing. The spreadsheet itself is quite usable though, complete with formatting tools and the capability to use formulas like a modern spreadsheet program would. It also hosted a tape deck for audio and data storage, a modem for communicating with other devices, and an optional plotter-style printer. The modem port is how [Old VCR] eventually interfaces with the machine, although as one can imagine is quite a task for a piece of small-batch technology from the 80s like this. After learning how to send and receive information, a small game is programmed into the machine and then a Gopher interface is built to give the device limited Internet connectivity.

The investigation that [Old VCR] goes into on this project to get this obsolete yet unique piece of hardware running and programmed to do other tasks is impressive, and worth taking a look at especially because spreadsheets like this aren’t Turing-complete, leading to a few interesting phenomenon that most of us wouldn’t come across in the modern computing world. Since only around 60,000 units were ever made it’s difficult to come across these machines, but if you want to take a look at the spreadsheet world of the 80s without original hardware you can still run Lotus 1-2-3 natively in Linux today.

Thanks to [Cameron] for the tip!

Ancient Cable Modem Reveals Its RF Secrets

April 22, 2024 by 27 Comments

Most reverse engineering projects we see around here have some sort of practical endpoint in mind. Usually, but not always. Reverse-engineering a 40-year-old cable modem probably serves no practical end, except for the simple pleasure of understanding how 1980s tech worked.

You’ll be forgiven if the NABU Network, the source of the modem [Jared Boone] tears into, sounds unfamiliar; it only existed from 1982 to 1985 and primarily operated in Ottawa, Canada. It’s pretty interesting though, especially the Z80-based computer that was part of the package. The modem itself is a boxy affair bearing all the hallmarks of 1980s tech. [Jared]’s inspection revealed a power supply with a big transformer, a main logic board, and a mysterious shielded section with all the RF circuits, which is the focus of the video below.

Using a signal generator, a spectrum analyzer, and an oscilloscope, not to mention the PCB silkscreen and component markings, [Jared] built a block diagram of the circuit and determined the important frequencies for things like the local oscillator. He worked through the RF section, discovering what each compartment does, with the most interesting one probably being the quadrature demodulator. But things took a decidedly digital twist in the last compartment, where the modulated RF is turned into digital data with a couple of 7400-series chips, some comparators, and a crystal oscillator.

This tour of 80s tech and the methods [Jared] used to figure out what’s going on in this box were pretty impressive. There’s more to come on this project, including recreating the original signal with SDRs. In the mean time, if this put you in the mood for other videotext systems of the 80s, you might enjoy this Minitel terminal teardown.

Continue reading “Ancient Cable Modem Reveals Its RF Secrets” →

Dial-Up Is Still, Just Barely, A Thing

March 6, 2024 by 94 Comments

In an era dominated by broadband and wireless cellular networks, it might come as a surprise to many that dial-up internet services still exist in the United States. This persistence is not a mere relic of nostalgia — but a testament to the diverse and uneven nature of internet infrastructure across the country.

Yes, dial-up internet, with those screechy, crackly tones, remains a useful tool in areas where modern, high-speed internet services are either unaffordable or unavailable. Subscriber numbers are tiny, but some plough on and access the Internet by the old ways, not the new.

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Replacement PCB Replicates Early 80s Modem

February 21, 2024 by 29 Comments

It’s certainly been a few decades, but plenty of us remember a time before widespread access to broadband internet, when connections were generally made over phone lines using acoustic modems. In the 90s these could connect you to AOL and Napster well enough, but in the early 80s the speeds were barely enough to read text as it loaded. A company called Hayes set out to change this with some of the first useful, widely-available modems for the PCs at the time. While they couldn’t keep up with the changing times there’s still a retro community that has these antiques, and to modernize it a bit this drop-in replacement for the PCBs replicates these old modems almost exactly.

The new PCB is equipped with everything needed to get a retro computer online again, including all the ports to connect a computer without any further modifications. It houses a few modern upgrades beyond its on-board processors, though. Rather than needing an actual acoustic coupled phone, this one has an ESP32 which gives it wireless capability. But the replacement PCB maintains the look and feel of the original hardware by replicating the red status LEDs at the front, fitting into the original Hayes cases with no modifications needed at all, and even includes a small speaker through which it can replicate the various tones, handshakes, and other audio cues that those of us nostalgic for this new online era remember quite well.

For those looking for a retro feel without the hassle of getting antique networking equipment functional again, this type of upgrade that preserves the essence of the original hardware is an excellent way of keeping retro computers functional on modern networking equipment. But if you absolutely must get the networking equipment exactly right down to the last patch cable, you might end up having to build your own ISP from scratch.

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Dial Up Over Discord

December 23, 2023 by 18 Comments

Some hacks are useful and some are just… well… for the fun of it, and we can appreciate that. Take, for example, [Cool Blog’s] recent experiments with dialup networking. If you think about it, the BBS systems of yesterday have been replaced with more modern tools like Discord. So why not run modems using audio chat over Discord and get the best of both worlds?

This was both easier and harder than we would have expected. The first hurdle was the lack of any actual modems. Luckily, there are software modem emulators like minimodem that makes a PC soundcard work like a modem. It supports some basic protocols, and that’s probably a good thing since the digital audio channel is probably unable to support anything too sophisticated.

Using some crude audio routing 300 baud data did flow. Increasing the baud rate all the way to 2,100 worked reliably. Combining some more sophisticated audio flows and managing sockets with systemd made the process easier. The goal was to, eventually, telnet over the link but that never worked. We would guess that it could work if you spent enough time.

But the proof is in the pudding, and the basic idea works. Why do it? We can’t think of a good reason. But if you want to give it a shot, you can find what you need on GitHub.

Hams still use modems. While we tend to have a soft spot for retrocomputing gear, we don’t miss acoustic couplers at all.

Commodore 64 Reports The News

March 22, 2023 by 13 Comments

In the late 80s and into the 90s, [Cameron Kaiser] aka [ClassicHasClass] was an aspiring journalist, first becoming interested in the career in elementary school and then working on various publications into university. At some point, he started using a piece of software for laying out newspapers called The Newsroom which, he admits, was lacking a lot of tools that would have been modern even for the time, but had an otherwise agreeable price tag thanks to its focus more on home desktop publishing and newsletter production than on full-scale newspaper operations. It did have one interesting feature that he never could figure out, though, at least until he went back and pieced this mystery together.

The software itself ran on the Apple II and was eventually ported to other systems of the era, including the Commodore 64. The mystery feature was known as “Wire Service” and appeared to be a way that users of the software who had a modem could connect with one another and share news releases, layouts, graphics, and other content created in Newsroom, but in the days where it would have been modern never was able to connect to anything. In fact, it was eventually abandoned by the developers themselves in later releases of the software. But [ClassicHasClass] was determined to get it working. Continue reading “Commodore 64 Reports The News” →

A laptop with a desk phone and a 3D-printed acoustic coupler next to it

Acoustic Coupler Gets You Online Through Any Desk Phone

December 30, 2022 by 48 Comments

Up until the mid-1980s, connecting a computer to a phone line was tricky: many phone companies didn’t allow the connection of unlicensed equipment to their network, and even if they did, you might still find yourself blocked by a lack of standardized connectors. A simple workaround for all this was an acoustic coupler, a device that played your modem’s sounds directly into a phone’s receiver without any electrical connection. Modem speeds were slow anyway, so the limited bandwidth inherent in such a system was not much of a problem.

Nowadays it’s easier to find an internet connection than a phone line in many places, but if you’re stuck in an ancient hotel in the middle of nowhere you might just find [GusGorman]’s modern take on the acoustic coupler useful. The basic design is quite simple: it’s a 3D-printed box with two cups that fit a typical phone handset and a space to put a USB speaker and microphone. Thanks to minimodem it’s easy to set up a connection with any other computer equipped with a phone connection.

Continue reading “Acoustic Coupler Gets You Online Through Any Desk Phone” →