PQ>    I have a modem, a PC-Tel HSP WinModem. This is a modem that is 
virtually
PQ>100% software. So it can only be used in windows.
A _WINMODEM_..!  That's a whole different thing entirely.  All you had
ever said was a HSP modem.
PQ>analogue. This is why a P75+ is needed to run the modem. Unfortunately it
PQ>doesn't
PQ>come with any Dos Drivers, and PC-Tel say that none will be written.
Correct.
PQ>    So I want to write some. I need to know how to intercept Comm port
PQ>intercepts
Sorry, it's not that simple.  Not even close to being that simple.  It's
not just a matter of taking the signals and converting them to/from
analog/digital.  There is a lot of very delicate signal processing to
deal with echo cancellation, terrible phone lines, data compression,
error correction (both MNP and v42bis type).
I've heard there is some code that you can run to turn some sound cards
into a 2400 baud modem, and that is not trivial.  Going from 2400 to
14.4k is a massive leap in programming requirements, signal processing,
licensing requirements (the specs are copyright....), and so on.
A lot of people have disliked the RPI and Winmodems because they don't
come with DOS drivers, but nobody is writing them because there are
simply too many details to deal with.
There _are_ software programs to do it. Several companies sell them.
All you have to provide is the I/O stuff yourself.  So, it can be done.
But they are extremely expensive and take quite a bit of processing
power.
Really, there is no justification for Winmodems to exist.  The cost of
manufacturing a Winmodem over a real, full 14.4k modem is almost
identical.  Adding the hardware to do the processing on the modem can be
done for, oh... $5, with the entire 14.4k modem being sold via mail
order for $40.
Incidentally, software versions (like Winmodem) of 33.6k and 56k modems
should appear in the not too distant future.
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