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.