While I understand your comments and that this can get hairy, also consider a softmodem-like implementation as a counter-example. A softmodem (variously also c

While I understand your comments and that this can get hairy, also consider a softmodem-like implementation as a counter-example. A softmodem (variously also called a Winmodem) is a partial or full software implementation of a modem, and helped reduce the parts counts and the costs of modems. Ugly or not, it's a near certainty that we'll see a software (or firmware) implementation of this; some sort of "softssd" or "winssd" scheme.