[hrishios]

I was just about to comment with the suggestion of adding a low pass filter for nyquist transformation, but reddit beat me to it!

Still amazing that it's a self-contained audio device, no actual addressing or protocol needed. It would be interesting if (as the author thinks) these were custom ASICs with built in songs from the factory, or some combination of EEPROM and decoder/driver chip. Does anyone remember what they sold for way back?