From: sreangsu acharyya <[EMAIL PROTECTED]>
>what if i use the sound card as a modem. I sure can "hear"
> data packets ona connected line...but are all of them within
>our audible range or moreprecisely reproducible by the
>sound card.
Alas this is where ur fantasy must disintegrate....
You need to transmit and listen from the same port.
How do u propose to bifurcate the listen && send function ?
U can't do that with the mic & line out or spk diff. The snd card
ports were never built with for something like a karoke facility ;-)
However , u've figured out almost halfway bout the workings of
an internal modem. No flames !! there was a time when I had
these ideas of using an ol fax machine as a scanner( I did succeed,though
the output was nothing to talk about :-} )
Bye
Kaushik
> i am not an electronics engineer, so please dont flame me if the
>following does not make sense.
>
> Thinking of ways to surf net for free, i thought of having a
>call-back system at my office. ( they will probably fire me if I actually
>do it...but no harm romanticising.)The 1st hurdle, is the office machine
>do not have a modem.
>
> I reasoned that, tone dialing is done by feeding "tones" into the
>receiver. Moreover these are certainly in our audible range 16-20k Hz,
>thus reproducible by the sound card.
>
> Thus given proper driver support wouldnt it be possible to use the line
>out of the sound card to dial some number. Upto this it seems ok, but
>what if i use the sound card as a modem. I sure can "hear" data packets on
>a connected line...but are all of them within our audible range or more
>precisely reproducible by the sound card.
>
> There are many issues however, getting the frequency right is ok, but
>the voltage output of the soundcard should be comparable to the one used
>on phone lines. About these values i have no idea.Moreover the speed would
>also be quite low if a sound card is used.
>
> The reasoning seems pretty elementary, and i am sure some one has
>thought about it. I searched linmodem.org and google.com/linux but couldnt
>get anything substantial.
> Please respond if you have any ideas.
> sreangsu
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