Inittab

The /etc/inittab file needs to have an extra 'tty' added for the modem so that dial-in access will be initialised upon a reboot.

There will be several lines in this file for the standard getty's, which will look like this:

1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6

You must add the line 7:2345:respawn:/sbin/mgetty ttyS0 to the end of this section, so the section looks like this:

6:2345:respawn:/sbin/mingetty tty6
7:2345:respawn:/sbin/mgetty ttyS0

You will then need to restart init by executing the command: kill -HUP 1.