I'm surprised (not that I'm trying to pawn mine off) that the Hayes MicroModem II is not a more desired item. They go for a-dime-a-dozen on ebay. And there's little to no discussion about these or their history.
http://en.wikipedia.org/wiki/Hayes_Microcomputer_Products
All modems still need to be somewhat hayes compatible, you know.
http://en.wikipedia.org/wiki/Hayes_command_set
Not really...
Many Modems were made before Hayes developed their modem...
My first Modem, was semi-Hayes compatible.. A "U.S Robotics Password" ( USR )
My friend Randy, had one that connected to the Phone with a Modular Jack, but was a "Dumb Modem", in that you used your Phone to Dial, and to detect an incoming Modem Call..
MarkO