Here I will relate our experiences with setting up 3G usb cards with the HP Minis running Ubuntu Netbook Edition 10.04.
We bought service and devices from AT&T (I was not involved in this purchase stage, nor with the minis, by the way). AT&T sent us LG USBConnect Turbo cards along with the sim cards. When we tried to plug in the cards, nothing happened.
After a lot of fiddling and researching I found out that the cards provided were new and not properly handled in Ubuntu (or many other systems it would seem). After a lot of digging and forum research I found this site and its utility: http://www.draisberghof.de/usb_modeswitch/
After following the instructions to setup the modeswitch utility, we were able to plug in the device, wait a few seconds and click on the mobile connection that shows up in network manager to open up a nice wizard to setup the card and connection. This process was very simple actually and after about a minute refreshing the connection was ready to click on agian with the proper data connect plan name from the list under network manager.
One drawback initially for us, of course, was the low AT&T service where we were intitially doing it, so once I initially got the fix in place we though it still wasn’t working because it wasn’t connecting to the internet. Later we found it worked elsewhere.
On a similar note, I have discovered from some other contacts that the LG USBConnect Turbo cards we were given are known to be very buggy and unreliable, known to be the WORST connect cards AT&T provides. We also found that the wipipes AT&T sent us for us to setup wifi hotspots simply are not compatible with the Turbo cards yet. Luckily some talk with our AT&T rep took care of this and AT&T has since sent us 15 new USB Connect cards, Sierra Lightnings. I have heard from my contacts that the Sierra Lightnings, which I believe are an older model, are actually the BEST USBConnect cards that AT&T provides.
This has been confirmed not only by the simple fact that the Lightning cards work with our WiPipes, but also by fellows who have taken and tested the cards in areas where they recieved no connection with the Turbo cards before and connect fine with the Lightnings.
Another issue to note with the Turbo cards that you may experience is randomly on connect it will ask for a password. We still have no idea what it was really asking for or what password, but pressing ok or entering random passwords will randomly work. Sometimes it won’t ask for a long time, sometimes it asks constantly, all I can determine is that this is simply a bug.
NOTE: From what I’m aware, though I have not had a chance to test this, the Sierra Lightning cards, and most USBCards, should be able to just plug into the netbook or other device with Ubuntu on it and work right away (well, after you use the wizard to setup your connection), without the need for the modeswitch fix.