braille configuration

[Moritz]

Hi everyone
I wrote some days ago how to install a braille display on a Ubuntu machine. 
Since then I tried to get the Braille working with brltty, but it just 
doesn't work. I now want to try my other braille display, an alva 40. But 
this one hasn't got a USB, but only 2 serial connections. Now my question, 
does Ubuntu need a programm to convert a serial to an USB? Or would it just 
work, if I connect the serial with the USB Port?
Off listers would although be appreciated, so my troubles don't bother the 
whole list :-)
Moritz.wyder at gmx.ch would be my addy.
thanks a lot
Moritz