I gotta support that request.
... I think Windows simply - under any circumstances - tells the modem to interrupt, i.e. it doesn't correctly terminate the connection (and leaves the problem to the other end of the connection which will then eventually timeout). Here we have one way on the Windows side, that is both wrong and 'better for the user' and the right way on the Mac side, which is 'worse' for the user... My guess is that ISPs have long accepted the way Windows does it and that the Mac doing it the right way isn't really needed any longer, but maybe no-one at Apple did come around to change it, anyway. And then I don't think many people at Apple are actually _using_ those modems, unless they're using their Macs for faxing.