12.5. WinModems
If you look at a modem, with it's small central processing
unit and special-purpose digital signal processor, and then look at
a modern PC, with it's large CPU
and general-purpose DSP on the sound card, you may
wonder if the hardware duplication of an external modem is
necessary.
A "WinModem" incorporates the
CPU and DSP of the modem into
the slightly-enhanced fabric of a PC. They are
called "WinModems" because they originally only shipped with
Microsoft Windows device
drivers. These device drivers presented the illusion of a serial
port attached to a Hayes AT-style modem. For a
long time only Windows
versions of these drivers where available. Some manufacturers now
provide Linux versions of
their device drivers as well, these modems are jokingly called
"LinModems".
It is probably possible to use a LinModem as a Linux console. At the most this would
require altering the source code to dumb-down the AT command
emulation of the modem and recompiling the kernel.
Boot loaders, however, work in a very confined software
environment and struggle to support a simple serial chip.
Considering that some boot loaders do not even handle interrupts,
handling the complex DSP of a LinModem is well
beyond what is practical.