I've been given an old tower made by Fujitsu-Siemens, with an
NS30/35/36-FS rev-C2 motherboard inside, which seems to have been made by
a company named DFI.

I just found the towers model name, embossed black-on-black (almost
invisible) on the front right side: it seems to be a "Scaleo 600". Alas,
it seems to have been sold with different motherboards and the found "users
manual" is written for exactly them, users (no mentioning of the wiring of
the motherboard).

Regards,
Rudy Wieser