WRT54GS, and I believe they share the same firmware. My version is 4.50.6. You can verify with linksys. Their phone support is not too bad.
I have the WRT54G with the latest linksys firmware (v4.00.7) and 2 computers using Trendnet tew-421pc (pc card for the laptop which is running windows xp sp2) and tew-423pi (pci card for the desktop which is windows 98se) and these cards are both wireless G. I installed the drivers and they seem to be working. On the desktop, I'm using the provided trendnet wireless connection software and on the laptop, I'm using the windows wireless zero thing. I can connect and use the internet, but only for a little while after I restart the router. When I try again the next morning, it doesn't connect at all. It gets stuck at 'waiting for network' forever, it doesn't crash, it just wont go any farther.

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