Subject: Modems

David Gibson david at
Wed Jun 19 16:20:08 EST 2002

On Wed, Jun 19, 2002 at 04:12:24PM +1000, Andrew Bartlett wrote:
> > Alan wrote:
> > 
> > In my quest to obtain a 'true hardware' modem I received the following
> > reply from the manufacturer
> > of a D-Link DFM-560i+.
> > 
> > >>Hi there,
> > >>Thanks for writing to us.
> > >>The DFM-560i+ is a hardware modem which only runs in Windows. The
> > processing is
> > >>done by the modem. Unfortunately the DFM-560I+ modem does not have
> > support for
> > >>Linux.
> > Does this make sense and is there a chance that I may get this to run
> > on my Linux machine ?
> Bullshit.
> A 'true hardware modem' presents a serial port interface to whatever OS
> is running on the machine.  
> The easy way to buy a hardware modem is to get an external, serial (not
> USB) device.


However, it's possible the source of the confusion is that they're
making a distinction between a DSP WinModem and an HSP WinModem.

A DSP modem will have one or more DSP chips which handle the hardest
work of the modem signal processing.  Hence arguably a "hardware"
modem, although it's not what I'd call a hardware modem. You still
need special drivers to program the DSP of course.

An HSP (Host Signal Processing) modem, on the other hand, is even
cheaper and nastier.  It does essentially all the signal processing on
the CPU - i.e. it's nothing but a (pretty dumb) soundcard with a phone
line instead of speakers, and the only thing that's "modem" about it
is the software.

David Gibson			| For every complex problem there is a
david at	| solution which is simple, neat and
				| wrong.  -- H.L. Mencken

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