The "35-cent" Commodore 64 softmodem

Rockwell famously used 6502-based cores in modems for many years, but that doesn't mean other 6502s couldn't be used. If only there were a way to connect a Commodore 64's audio output directly to an RJ-11 plug ...

Of the many interesting posts from Usenet's more golden days, one of my favourites was John Iannetta's "35-cent modem," where the SID chip provides one-way data modulation to a receiving modem connected via the C64's sound output. While I remember him posting it back in 1998, I never actually tried it at the time.

Wouldn't you know it, but it came to mind the other day when I was looking at a recent haul of Convergent WorkSlate stuff I've got to catalogue. Officially the WorkSlate's only means of telecommunications is its 300 baud internal modem. While we have a 9600bps way of wiring up a Workslate to a modern computer, it's always nice to have a simpler alternative, and I figured this would be a great challenge to see if John's old program could let my Commodore SX-64 talk to my WorkSlate. Spoiler alert: it works!

Refurb weekend: Atari Stacy

Ask any Atari Stacy owner how to open an Atari Stacy and the answer is always "never, if you can avoid it." So I'll just lead with this spoiler image after the refurb to prove this particular escapade didn't completely end in tragedy:

Stacys are horrible machines to work on. Nobody likes being inside of one. The daughterboards don't have keyed connectors (including the power supply!) and are constantly attempting to come free, the display "cable" is actually a Medusa's wig of wires that like to short (!), the top case is a huge bulky sheet of increasingly fragile plastic that somehow has to fit around the floppy drive yet down on the keyboard simultaneously, and the entire laptop is an uneasy sandwich held together by a small set of screws in plastic races that strip and fracture with little provocation. So why do we tolerate this very bad, bad, bad, bad girl? Because most of us will never see the much lighter and streamlined STBook in the flesh, let alone own one. If you really want a portable all-in-one Atari ST system, the Stacy is likely the best you're gonna do.

And we're going to make it worse, because this is the lowest-binned Stacy with the base 1MB of memory. I want to put the full 4MB the hardware supports in it to expand its operating system choices. It turns out that's much harder to do than I ever expected, making repairing its bad left mouse button while we're in there almost incidental — let's just say the process eventually involved cutting sheet metal. I'm not entirely happy with the end result but it's got 4MB, it's back together and it boots. Grit your teeth while we do a post-mortem on this really rough Refurb Weekend.