For the USB, have a look at http://www.usb.org /. Also, any USB host or
function chip will give you a good idea of what is going on in there. The
Netchip NET2890 datasheet has some good stuff on how the USB communications
works. I'd try the same with the ethernet information.
I'm assuming that by DTMF you're referring to the dual-tone frequencies.
Just do a search on google as there is a tonne of info on this, though I
don't have any links off hand.
Michael Hims wrote:
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