How to upgrade a laptop to 802.11 abg for $30
Many people who bought a laptop only have 802.11 b/g 2.4 GHz capability because that's what the computer came with. Now that the 802.11n standard is getting ready to completely jam the 2.4 GHz spectrum, 802.11a operating at 5 GHz is still the best way to avoid the spectrum hogs. The 5 GHz spectrum is not only abundant in spectrum with 4 times the number of unique channels (in North America), but few people use it making it wide open sailing. But you'll be surprised to see how many places are actually offering 802.11a access because almost all enterprise-class access points are dual-band. Having an 802.11a capable laptop allows you to instantly jump ahead of the line while everyone else sits in packet-to-packet traffic.
One way to upgrade your laptop to 802.11 a/b/g capability is to simply plug in a Cardbus adapter. The problem with this is that not only is it more expensive ($50 to $80), the adapter usually protrudes more than an inch out the sides and ruins the ergonomics of the laptop. Intel provides one of the cheapest ways to upgrade your existing laptop with the Intel PRO/Wireless 2915ABG miniPCI adapter at $30 which is almost half the price of other solutions. Note that for newer Core Duo or Core 2 Duo based laptops that come with mini PCI-Express slots instead of miniPCI, you'll need something like the Intel PRO/Wireless 3945 which also costs around $30. At $30, this is even cheaper than what a lot of PC vendors are offering as an upgrade price when you're shopping for a new laptop.
The Intel wireless cards are used in all Centrino branded products and they have excellent range. Intel also has an excellent driver support track record on their wireless products and they even added WPA2 and AES support to their original 802.11b wireless adapter used in the original Centrino product. A lot of hardware vendors leave relatively new products hanging and never bothered to add WPA let alone WPA2 support. To help you upgrade your system, here is a step-by-step guide on upgrading an IBM ThinkPad X40 notebook using the miniPCI Intel2915ABG adapter.
Step 1: Buy cheap $30 miniPCI or mini PCI-Express card
Note that not all laptops allow you to get access to the miniPCI slot from the bottom. Some laptops put the miniPCI slot under the keyboard which requires you to open up and lift up the keyboard which is a little trickier.Step 3: Note the location of the antenna connectors
There are usually 2 antennas built in to recent notebooks. You have the MAIN and AUX cable connectors in the red square. All you need to do is push out the holders located on the top and bottom of this image to remove the miniPCI adapter. Then remove the antenna connectors and attach them to the Intel2915ABG adapter before you plug it in to the slot. Once you plug it in to the slot and snap it in to place, you're ready to put the cover back on and fire up the laptop.Step 4: Nasty surprise from IBM with 1802 ERROR!
It appears that IBM has locked the user out from being able to add their choice of miniPCI adapters. I found the solution on Command-Tab which talks about an assembler program called no-1802.com. Command-Tab even has pre-made boot images ready to go so you can make your own boot floppy or boot CD. I had to remove the Intel miniPCI card first to get the system to even come up but you should run this procedure before you attempt the upgrade to begin with. Once you boot the CD or floppy, just type no-1802 and it will modify a CMOS setting that you can't change any other way. It's interesting to note that no-1802.com is written in Assembler and only takes up 18 bytes of space. Once you remove the 1802 restriction on your IBM ThinkPad, you can put any miniPCI card in. The affected models are listed here.
WARNING on the device drivers:
DO NOT use the drivers that come with the adapter, there is a critical remote exploit vulnerability on it. You need to get the updated drivers here.
PROSet Driver installation tip:
If your company already uses a standardized wireless connection manager like the one built in to Windows XP SP2, Funk Software's Odyssey client, or Meetinghouse Data Communications (recently acquired by Cisco), make sure you choose a "driver only" install. DO NOT install the PROSet driver software, it seems a bit bloated sometimes and it will slow the "Network Connections" control panel down in my experience. If you're an individual user and you have Windows XP SP2 plus the Microsoft WPA2 patch (get this if you haven't already done so), you should also do a "driver only" install and not the full "driver plus software" install. If you are running an older OS like Windows 2000, you'll want to install everything since it gives you full WPA2 capability on Windows 2000 which you can't get natively from the OS.
[Update 9/7/2006] A step-by-step PROSet installation gallery has been posted.