hi people,
DISCLAIMER:
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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