Experience with recent WLAN hardware (Netgear WG 511, TRENDnet TEW-421PC)

[Michael Marte <marte@pms.informatik.uni-muenchen.de>]

Hello *,

last week I experimented with WLAN PCMCIA cards on my Dell Latitude
CS400XT running 2.6.10.

First I bought a Netgear WG 511 (54Mbit/s) which is reported to work
properly using the native Linux driver for Prism chipsets. As it did not
work at all, I did some research on the web and found out that new cards
use a reduced chipset - the driver developers refer to it as SoftMAC as
opposed to HardMAC - which is more like a Winmodem in that it requires
heavy support by the CPU. Despite the severe change in implementation,
Netgear did not change the card's identifier s.t. hotplug identifies it a
as prism card and tries to load the prism driver. It seems that all
Netgear cards "Made in China" have this problem and that in Germany only
those cards are being sold at the moment. So hands off - also if you plan
to use it with an older Windows machine because of the heavy CPU load the
driver causes. I returned this card.

Then I went and bought a TRENDnet TEW-421PC (54MBit/s) which is based on a
Texas Intruments ACX-111 chipset. There is a native Linux driver but the
documentation says that it is higly experimental with regard to ACX-111. I
did some more research and came across another potential solution namely
ndiswrapper. ndiswrapper is an adapter that simply connects any Windows
network device driver that implements the so-called NDIS interface to the
internal Linux kernel device driver interface. (NDIS is a well-documented
interface specified by Microsoft and others and, as I understood, Windows
network device drivers have to implement this interface.) In other words,
you use the Windows driver that is distributed with the device and that
you have paid for. Unfortunately the ndiswrapper kernel module is not part
of the kernel image so I had to compile myself :-( Luckily it was not
too difficult. I needed to install the kernel headers (e.g. apt-get
install kernel-headers-2.6.10) and a tool called module-assistant. Then,
with a single line (like "module-assistant auto-install ndiswrapper", I
cannot remember exactly, see the ndiswrapper documentation) the
ndiswrapper source was downloaded, unpacked, compiled and the resulting
module was installed, like magic :-) Moreover, I needed to install the
ndiswrapper user-space utilities that are required for installing Windows
drivers (say something like ndiswrapper -i
dir-where-Windows-driver-resides). Then, with "modprobe ndiswrapper" the
Windows driver was loaded, a green LED on the card turned on and "ifup 
wlan0" established the connection. Great! The card actually works fine 
for me, both on Linux and Windows 98.

Michael