I have one ADSL modem from Vitelcom with Conexant chipset.
Does somebody knows how to make that the modem works and can it connect me to internet?
Have you tried running the Internet Configuration Wizard? It's in the "System Tools" menu.
It worked for my ADSL connection, I don't know (or really care) what my modem chipset is.
It may depend upon your provider too. Some (like mine) require IE to configure the modem, and they mean it - try with any other browser, and it fails. Once set up though it works (for me) regardless of what OS is connecting through it.