> So I thougt about a WLAN from my room to the cellar. It's a
> distance of about 10 meters. But the signal has to go throug an
> other appartement and I don't know if that works.
> I need a maximum of 400 kbit/s connection in both directions. I'm
> sure there is an access point which can do that, but it should not
> be too expensive.
Consider Powerline (HomePlug) as an alternative. I've had good
success in the very same situation (massive concrete basement, no way
with WLAN), at effective speeds of around 3 Mbps. Only thing I had to
do was hooking up the Powerline bridge in the apartment to an
otherwise unused outlet (not the one with all the computer stuff
connected to it). I do suspect however that the wall outlet in my
compartment of the basement was wired to my apartment's fuse box, as
Powerline signals usually can't travel across electricity meters. If
you can borrow two Powerline bridges, it's definitely worth a try