Research on Interfaces and Possibilities,

USB mode

Host Mode

USB host mode allows you to connect various USB devices (external hard drives, digital cameras, card readers, input devices, etc.) to your device just like a regular computer. There are, however, a few limitations. The device must draw under 100mA (this can be bypassed by using a powered hub), and you will need a hardware adaptor to plug a fullsize USB cable into the tablet's undersized one.

OTB - On the Go (http://en.wikipedia.org/wiki/USB_On-The-Go)
http://wiki.maemo.org/USB_host_mode
http://maemo.org/downloads/product/OS2008/usbcontrol/ (geht nicht für N900)
Allows to swich to hostmode and use USB devices like Keyboards

[?] - N900 []bekommt man es zum Laufen?
http://www.maemo.ch/usb-otg-kommt-bald-furs-n900/1533 (offenbar sind sie dran
http://wiki.maemo.org/N900_Hardware_USB_Host

Recherche 2010-09-08:

 es ist softwaretechnisch möglich, Lösungsansätze scheinen da zu sein, noch nicht "reliable" (auch nicht fuer developer)

Switching modes manually
Geht wohl nur fuer Vorgängermodelle -N8xx
To manually switch USB modes, you must first have rootsh installed, then open xterm and type:
"rootsh" installed

 sudo gainroot
 echo host > /sys/devices/platform/musb_hdrc/mode

The tablet will then be in host-mode and you can use your USB peripherals. To set the tablet back to client mode, open xterm again and type:

 echo otg > /sys/devices/platform/musb_hdrc/mode

LAN / USB-Interface

Posted 02-11-2010

is it possible to connect N900 to the wired LAN by using micro usb to female usb adopter+usb lan card+ethernet ???

No, the N900 doesn't support USB host mode, so this won't work.