Dear all,

I've discovered the problem is not in driver, but in NetworkManager (in Gutsy, nm-applet 0.6.5).
Look at these pages:

http://live.gnome.org/NetworkManagerHardware

Unsupported or Unknown Cards & Drivers

rt73
Status: Doesn't work with NetworkManager, but driver is good enough to get WEP/unencrypted connections "by hand"



http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Linux.Wireless.drivers.802.11ag.html

4.11 Ralink RT2500 and 2570 cards
Driver status : 	Beta
Driver name : 	rt2500.o
PCI : rt61.o
USB : rt73.o
rt2x00.o
Version : 	1.1.0 (beta) and 2.0.4 (alpha)
Where : 	http://rt2x00.serialmonkey.com/
http://rt2400.sourceforge.net/
http://www.ralinktech.com/supp-1.htm
Maintainers : 	Paul Lin
Mark Wallis <markwallis at users.sourceforge.net>
Ivo van Doorn <ivd at euronet.nl>
Mailing list : 	http://sourceforge.net/mail/?group_id=107832
Documentation : 	Text files, Howtos
Configuration : 	Wireless Extensions and specific graphical tool
Statistics : 	Wireless Extensions
Modes : 	Managed, Ad-Hoc
Security : 	WEP, WPA
Scanning : 	Wireless Extensions
Monitor : 	Yes
Multi-devices : 	?
Interoperability : 	802.11b, 802.11g and 802.11a depending on hardware
Other features : 	-
Non implemented : 	-
Bugs : 	SMP problems
License : 	GPL
Vendor web page : 	http://www.ralinktech.com/
http://minitar.com/
http://rt2x00.serialmonkey.com/wiki/index.php/Hardware

4.11.1 The device
Ralink may have been late in releasing a 802.11b chipset, the RT2400 (section 3.27), however it was fairly quickly followed by the RT2500, a 802.11g chipset. The RT2500 is a evolution of the RT2400, and share many characteristics with it.

Like other 802.11g chipsets, it supports standard OFDM bitrates up to 54 Mb/s and all modern 802.11 features such as WPA and QoS (802.11e). On top of that, it support a proprietary 72 Mb/s bitrate. The RT2500 is designed for MiniPCI and CardBus interfaces, and the RT2570 is designed with a USB 2.0 interface.

As usual, this chipset is sold by a wide variety of vendors under different model names, and some of those use the same model name for different chipsets. The project pages includes a long list of cards including this chipset. A special mention to Minitar which has a dedicated Linux support forum.

The RT2500 was quickly followed by other 802.11g chipsets. The RT61 family includes the rt2561 and rt2661 PCI chipsets and adds support for turbo bit rate (100 Mb/s) and for the rt2661 only proprietary MIMO (not 802.11n compatible). The RT73 family includes the RT2573 and RT2571 USB chipsets, and is the equivalent of the RT61 (but without the MIMO chipset). Those chipset are available with two radio options, 2.4 GHz only, or 2.4 GHz plus 5 GHz, for additional 802.11a support.

Ralink has now released the RT2800 family. The main feature of those chipset is the addition of draft-802.11n MIMO support.

4.11.2 The driver
Like for the RT2400, Ralink wrote a Linux driver for the RT2500 and RT2750, but this time they decided to release it themselves as GPL. Moreover, the driver is functional, full of features and with a graphical utility, so this represent a very generous contribution to the OpenSource community. The driver supports WEP, WPA, Scanning and Monitor mode...

Mark integrated this driver in the existing SourceForge project for the RT2400 driver and started to maintain it. Many patches have been integrated to improve the stability and functionality of the driver.

After that, Ralink released the RT61 driver and the RT73 driver, to support the new 802.11g chipset. Those drivers are GPL and have the same features as the RT2500 chipset. Mark has integrated this driver in the existing SourceForge project, and the community is provided various improvement to those drivers.

Ivo has started a rewrite of those drivers, called rt2x00, his goal is to have a source code easier to integrate in the Linux kernel and to maintain. His rewrite targets both the RT2400 (see section 3.27), the RT2500, the RT61 and RT73. The initial version of this new driver was using the Intel ieee80211 stack from the Centrino driver (see section 3.28).

Then, Ivo ported the driver to the new mac80211 kernel stack (see section 4.9), and lots of development has happened on that version of the driver. This alternate version is available in the wireless-dev GIT repository and in the CVS, and should appear in a Linux kernel in the future.