In order to log in to our server through the serial port we will need to activate this in the file /etc/ttys. Change the following line
tty00 "/usr/libexec/getty std.9600" unknown off
to the following:
tty00 "/usr/libexec/getty std.9600" vt100 on secure
Before you reboot the machine note two important things. First the word secure means that root can logon on tty00 which is otherwise disabled. If you don't need to logon as root on that console simply skip the secure.
If you are having trouble logging on (after a reboot) from your other PC (e.g. Windows using Hyperterminal) then you might want to try and change the leading tty00 to cua00.
If you do not plan on attaching a monitor to this box at all then you might want to create a file /etc/boot.conf with the following content:
set tty com0
in order to send boot messages to the serial console rather than showing them on the screen.