David Griffith wrote:
It certainly is of interest. I'd like to get
one of those for
myself. It shouldn't be too terribly hard to homebrew one of these
things into a shoeshine box, right?
"Pennywhistle", Popular Electronics,
March 1976.
If you don't really need a design that old, you might be able to find a
TMS99532 or Am7910 FSK modem chip.
You're making me feel very old. I used a 7910 the other week..
Somewhere I still have some blank PCBs for the 'Maplin Modem' project.
This was a 300 baud modem (CCITT tones) using the Motorola 14412 chip
They couldn't get the demodulator section of said chip to work properly,
so they added a 2211 or something.
I probably still have a 14412 in the spares box.
-tony