Sorry to rain on these guys advice... but ditching any of the three distros mentioned here due to 'some' driver issues--without knowing
they are solved by another--is poor advice. Can you guys verify that his issue will be corrected with either distro or are you advising a noob to reinstall a system just to find out?
My advice is to begin learning the basics, you will get nowhere if you just avoid them. Modems are unfortunately not the simplest of hardware to configure in linux (some work, some just don't).
The modem in question (Ambient chipset 5628D - Intel chipset 536ep?) is a partial DSP modem.. a linmodem, meaning that you need software drivers to support the chipset. There are partial open-sourced drivers supplied by Intel, but they are not fully open, and therefore will not be present in Fedora (ever)... probably not in the others either. There may better fully open-source alternatives.. but I haven't been able to locate them in my quick searches of the likely places. You may be stuck using Intel's driver to use your modem.
describes the chipset and links to Intel's driver download page. There are 'beta' drivers available here
. I personally would compile this
tarball for Fedora and see how that works but you may want to start with the actual Intel driver
If the chipset description above is incorrect or I have identified the wrong modem information for you please specify more precisely what the modem IS. The page linked below can help you do that.
For more information on modems in linux see this page