Sorry for my unclear post.
The /etc/inittab contains these lines:
# Local serial lines:
#s1:12345:respawn:/sbin/agetty -L ttyS0 9600 vt100
#s2:12345:respawn:/sbin/agetty -L ttyS1 9600 vt100
I meant that you may need to change the agetty options in these lines.
Also, please note that minicom allows you to set the RS232 options. Start minicom with the -s option.