Hi Tony I doubt they'd take it directly. Most have anti-aliasing filters that roll of before this. I think what the other fellow was refering to was to use the DSP on a sound card but not through the audio A/D part. Many sound cards used industry standard DSP chips the were reprogrammable with flash or on board RAM. The DSP chip I'm looking at on a modem card is a AD2116. It runs at about 16 mips and has very efficient indexed addressing with increment. This is more than fast enough to bit bang a floppy signal. To sample a digital signal asynchronously really takes a sample rate of at least 4X ( Shannon's says 2X but that is in theory with analog and brick wall filters ). Most serial chips use 16X. Since you need to detect edges, you need to be running at a sample rate of near 4 to 8 megherts to stay up with a signal from a floppy at 500khz data rate. Dwight