Making sense of a serial connection to an ss4000 NAS

update: I consider the unit bricked and will donate it to an open source enthusiast.

I'm trying to make sense of this serial connection on my Intel ss4000 nas (a better picture can be seen here).

I found this dl10-db9 connector in an old computer, should be okay right ?

First problem is that this little cable fits in the pin header in two directions, so I have to figure out the correct way to insert it in the pin header.
The pin header has a whole in its casing on one side, and as far as I can tell from pictures on the internet the red line of this little cable should be on the right side, as in this picture:

I then connect this to a brand new serial cable into a real serial port on another Debian computer. All of the following commands give a blank screen when all cables are connected and the NAS is running(*).

cu -l /dev/ttyS0 -s 9600
cu -l /dev/ttyS0 -s 19200
cu -l /dev/ttyS0 -s 115200
cu -o -l /dev/ttyS0 -s 9600
cu -o -l /dev/ttyS0 -s 19200
cu -o -l /dev/ttyS0 -s 115200
screen -l /dev/ttyS0 9600
screen -l /dev/ttyS0 9600 8N1
screen -l /dev/ttyS0 19200
screen -l /dev/ttyS0 38400
screen -l /dev/ttyS0 115200

115200 should be the correct transfer rate.

If I connect the little cable with the red line on the left side (pin 9 of the header according to this blog) like in the below picture, then all of the above commands give me lots of garbage (at different speeds...) on the screen.

How can I get this serial connection to work ? Do I have to reboot the NAS with every attempt ?

(*) The NAS does not respond to ssh or ping since the last 'aptitude update && aptitude upgrade' :(