The Linksys WPC54GS-UK PCMCIA card described in this article is called a "Wireless-G Notebook Adapter with SpeedBooster" on the box, and is based on a Broadcom chipset.
2. Identifying the card
To find out if this guide applies to your card, make sure the card is plugged in and type the following into a terminal window:
Among the lines output you should see something similar to the following:
05:00.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g] 802.11g Wireless LAN Controller (rev 02)
3. Installing the Broadcom firmware
A more detailed description of the Broadcom firmware installation can be found at WifiDocs/Driver/bcm43xx.
For a quick installation that worked in Ubuntu Edgy 6.10 with this card, type the following commands to install extra packages:
sudo apt-get install bcm43xx-fwcutter sudo /usr/share/bcm43xx-fwcutter/install_bcm43xx_firmware.sh sudo apt-get install network-manager network-manager-gnome
Assuming it all installs without errors, when you plug the card in again you should see an additional network icon in the panel at the top of your screen, from which you can connect to your wireless network.
4. Features supported
WPA support has been tested and works with NetworkManager.
Currently NetworkManager shows full signal strength for all networks in the list, though it does correctly display the signal strength for the currently connected wireless network.