I posted this same info at linksysinfo.org

I just bought the new wap4400N and I am not impressed.

I have 4 wireless cards and I got only one to work.  Dell truemobile1150  senao 802.11g card.  3com travel router setup as client.  linksys wmp54g NIC.

I have tried out various configurations and nothing seems to work. 

I received the item Friday. I got it setup with my business net IP address and updated to the latest firmware.  I saw problems with the dell from the start with 4400N not allowing the connection I could not get it connected. I tried with the senao and everthing worked. I thought that was odd,  g worked but the b would not.

{Later,  i had to meet a co-worker at panera and my dell connect right away}  I get home and same issue with the 4400N.

Today I completed my initial testing.   The distance of the 4400N is pretty good. I am about 100 ft away and still have 60%.  In my environment, I have an average of 25 ft.

Back to the connection problem.

I check to make sure the dell was scanning and it was.   I usually hide the WAP ssid but with all the problems I set it to not-disable.  I used netstumbler and once I told it to have the ssid “set to show”  netstumbler found the SSID.  The network setting shows the SSID but it would not connect.  I press the connect button and it still would not connect.

Lastly I took a WMP44G that was connecting to my other WAP54G and change the priority and make the WAP4400N show first.   I saw the WMP see the 4400N but I see it quickly disconnect and the WMP connected back to the WAP54G.  I removed the SSID on the WAP54G and the WMP would not connect.

I also played with the network type (B/G type,  B only, and B/G/N type)  and it worked to specs.  the computers show the type when activated.  I did not test a N only card since I do not have one.

based on this initial I think there is something in the frimware code not letting certain mac through.