On 5 Jan 98, at 0:00, Dennis Noble wrote:

> >At 08:45 AM 2/11/99 +1300, you wrote:
> >>Can someone tell me what a Winmodem is? I see it mentioned alot on the
> list.
> >
> >A Winmodem is basically a modem that only has one processor on it instead
> >of two. I can't tell you exactly what the processors do on a modem, but I
> >can tell you that two are required. With a Winmodem, the one on-board
> >processor does it's job, while the duty of the second is performed by the
> >main CPU of the computer. On a "real" modem, these duties are performed
> >on the modem itself.
>
> I believe that both of the modems that you described are "WinModems". I
> believe that you have described the difference between a "SoftModem" and a
> "HardModem".

  We *could* argue about nomenclature for weeks, but according to Altacom,
a company General Magic spun off two years ago (which has since been sued
by Motorola alleging a patent conflict...), a "SoftModem" is implemented
*entirely* in software, except for low-level D/A and A/D conversions
between the phone line and the CPU.
  A "hard" modem is a device that sits between a serial port and a
phone line and translates back and forth.  In the case of an external
modem, it's in its own box with dedicated power supply, etc.; in the
case of an internal, it may be mounted on the same card with the serial
interface.
  A "WinModem" (USR/3Com trademark, although others sell similar
devices) provides a hardware serial port and phone line connection, but
implements SOME modem functions in the driver software that runs on the
main CPU.  I suspect that this is what a "one processor" modem above
refers to; there is still some processing done on the modem, but not
all of it.
  The required drivers are provided for Windows, but few manufacturers
of these devices provide drivers for any other OS.  [Hard modems may
come with a Windows driver, but they can be used from just about any OS
that offers a serial interface.]

  Generally, implementing part or all of a modem in software lowers
manufacturing costs, at the risk of impairing (a) performance of other
parts of the system while the modem is in use, and (b) compatibility
with alternate system software.  Sometimes you don't get to choose
which criterion is most important to you....


David G

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