[mdlug] Serial port monitoring

[Drew]

     I wish to write a script that returns a TRUE value if and only if
(1) VMware is running, AND (2) the serial port (/dev/ttyS0) is actually
connected through the modem and phone line to a remote host. To this
end:

* How may the state of Carrier Detect be read?

* If there is no actual modem, but just a straight serial connection
   using pins 2, 3, and ground, can reading Carrier Detect in that
   manner be relied upon to return an OFF status?


     Then, I want to set up a permanent cron task that runs once a
minute, executes the above script, and increments a counter (to be
reset at the beginning of each month) on each TRUE return. How does
one set this up?

     I am running Fedora Core 4.

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   - Drew.