Configuring dial-in under Red Hat Linux 6.X
===========================================

1. Configuring the modem:

   If the modem has an external bank of DIP switches, make sure that the
   following features (if configurable) are set:

      Result code display
      Verbal result codes
      Power-on and ATZ set factory defaults
      AT Command Set recognition

   Also, check to make sure that the following features are *not* set:

      CD override
      DTR override
      Auto-Answer (*)
      Command mode echo suppression
      
2. Confirming the software is installed:

   At the command prompt, type the following:

      rpm -q -a | grep mgetty

   You should get one or more packages back from this. The one that is 
   required for dial-in to function will look like this:

      mgetty-<version>.i386.rpm

   If this package is not installed, place the Red Hat CDROM into the drive and 
   type the following commands:

      mount /dev/cdrom
      cd /mnt/cdrom/RedHat/RPMS
      rpm -ivh mgetty*rpm

3. Next we have to edit the /etc/inittab file.  You will need to add a line 
   with the following format:

      <tt>:2345:respawn:/sbin/mgetty -x 3 <device>

   Replacing the <device> with the device name of your serial port (e.g. 
   "/dev/ttyS0" for "com 1") and the <tt> with a unique identifier for that 
   port (a common convention would be to use the last two characters of the 
   device name, e.g. S0 for /dev/ttyS0, S1 for /dev/ttyS1, etc.)

4. Once this is completed, we need to restart the "init" process to start the 
   service. To do this, type the following command:

      telinit q

5. At this point you should be able to test the setup.

* This seems counter-intuitive, but it is in fact necessary, as the mgetty 
  process relys on seeing the string "ring" sent by the modem to the serial
  port.