Hi Jackjohn,

i also think that the n900
should work with a serial usb adapter
but i am not sure if the power-kernel
have the right driver for your device

if possible you could check the hardware id
from the terminal "lsusb" should give you a hint
which serial adapter you have
and which driver is needed to get the adapter running^^

greetings from germany
Hoga

PS: after looking for idProduct=2303
i got http://www.linuxforen.de/forums/showthread.php?t=272802
this is a german link^^

someone worked around
with a simple "modprobe pl2303"
in the terminal on a beagleboard^^

so give it a try and if it works you could add pl2303 to /etc/modules