I like how this sounds, but then again, I probably wouldn't

If you want an idea of the circuitry that was originally used in these kind of interfaces, this is a cassette tape interface I built around 1979. I think it might have been based on a Don Lancaster design. It worked at 300 baud and was quite solid and reliable recording and playing back. The large chip is a UART. The panel switch is labelled play and record. I think that the relay controlled the motion of the tape, somehow, maybe via the small mains PSU I built to power the recorder to save on batteries.

If you want an idea of the circuitry that was originally used in these kind of interfaces, this is a cassette tape interface I built around 1979. I think it might have been based on a Don Lancaster design. It worked at 300 baud and was quite solid and reliable recording and playing back. The large chip is a UART. The panel switch is labelled play and record. I think that the relay controlled the motion of the tape, somehow, maybe via the small mains PSU I built to power the recorder to save on batteries.

jc2048 Thank you for the reference, I believe you are referring to Don Lancaster’s “Bit Boffer”

www.tinaja.com/.../bitboff.pdf

It's very possible, though I don't now recollect the article. I didn't get to see Byte much until later - the various magazines weren't imported here in the UK very much at that stage, but I did obtain from somewhere the first book where they rolled together a lot of the more interesting content, so perhaps it was from that. I might still have it - I'll have a rummage around later.

The only US magazine I read regularly was Dr Dobbs, which I had a subscription to for a few years (it got flown over air mail). For a while, that had some really good stuff in it - I can remember rewriting one of the various Tiny BASICs that appeared, from 8080 code to 6502. Indeed that might have been part of my motivation for doing the cassette interface: it would have been painful entering that in machine code every time I wanted to use it.

He included the 'Bit Boffer' in his TV Typewriter Cookbook. So that's where I came across it.

Would it work if stanto  simply took the analogue bits (with maybe an actual comparator on the input to the receiver, rather than using the 3130 op amp) and attached them to a Pico? Could the PIOs emulate what the CMOS logic is doing and the program emulate the UART? If so, that might be the simplest and cheapest way to do what is being asked for.

You built it in 1979, I just finished high school and you still have the book. Impressive or horder, not sure on that? Actually I know I still have my college text books from that year. My missus keeps asking me to throw them out.

I threw out the missus 

OK, I guess it's about time I trim my library. I hereby resolve to throw out my 1980's textbooks before the end of the year. For sure that will be worth lots of points from my beloved.

I guess I should do the same with my textbooks from the 1970's.  I am currently taking a break from the task of cleaning up my office space as we have company coming soon.

Tricky one, I had a clear out of my 80s books only to end up tracking down and rebuying some of them a few years later, when a retired colleague decided to start another vintage restoration project.

Those books that had been in arms reach all those years, now had to be tracked down in the second hand shops. I paid more in international shipping alone than the original new book price, just to get a dog-eared replacement to place back on that shelf.

I’ve had that same experience of discovering that something (book, magazine, hardware) that I had given away or thrown away would have been the perfect solution to some problem that I had.  My wife didn’t believe that until I encountered problems that I couldn’t fix without that stuff.

My experience is that the moment I throw a book out it will be needed within a week.

That said, I now have a policy that I have to throw out 2 books for any I buy.

That basically means I no longer buy any books.