Script to check whether modem telephone line in use --- how?

[Mark Phillips <mark@ist.flinders.edu.au>]

This morning I typed "pon" to dial up a ppp connection, only to hear
noise on my modem to idicate that the line was already in use.  I
quickly typed "poff", but it was too late --- I had already killed my
father's connection to the internet.  He was not pleased as I had
killed his connection near the end of an 8M download.

Anyway, I don't want this to happen again, so I would like, if
possible, to write a script which does nothing except listen to the
modem line for a few seconds so that I can hear whether someone else
is using it.  I have some idea about how such a script would go, but
would appreciate some input.  Here is what I propose:

#!/bin/bash

echo atm2 > /dev/ttyS1
echo ato0 > /dev/ttyS1
pause 2
echo +++ > /dev/ttyS1
pause 2
echo atm1 > /dev/ttyS1


I'd appreciate any comments about whether this is the best way to go
about this problem.

Thanks,

Mark.



_/~~~~~~~~\___/~~~~~~\____________________________________________________
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        "They told me I was gullible ... and I believed them!"