Officially speaking, Diva ADLS USB modem is not compatible with Linux.
However, guys from
http://www.prout.be/eicon/ made it fairly compatible.
Since I use their driver I have no problems. Installation is super easy. I don't remember which file (README or INSTALL) lists all you have to do.
Well, download the tarball from
http://www.prout.be/eicon/.
Unpack in /home/yourusername/tmp/
It will create a folder eicon-0.0.-I-dont-remember-what-else.
cd to eicon-0.0.-I-dont-remember-what-else
Run the linux trinity ("../configure", "make", "make install").
Manually edit two or three files depending on your ISP (You have to know only IP of your ISP, user name and a password.)
Run a couple of terminal commands described in README or INSTALL.
Once its done, open terminal and run startmodem as root. One or two errors might arise. Run an included (nice!) debug script. It will tell you what is wrong and what you have to do (nice!). Else, look in README for solution. If everything is fine you will be connected.
It took me 5 minutes to install and connect. Earlier I found this trick here at LQ, but I couldn't find they guy who pointed me to
http://www.prout.be/eicon/.