Basically there are two kinds of dialup modems: those that are called "hardware" or "real" modems, and those that are called "software" or "winmodems". "Real" modems used to be slightly more expensive than the "winmodems". You can read more about their differences, and why you would only want to buy a "hardware" modem, from various internet sites, probably at Wikipedia too. Anyway, if you have a non-winmodem, it should work without trouble: just launch your PPP app (which looks quite a lot the same as the dialog you use in Windows when you configure a new dialup connection) from the menu, fill in needed information (modem device file if /dev/modem is not there [it should be], dial number, etc.) and dial out. Not sure what ppp application Fedora provides you with, but there are many of them, both graphical and command-line ones. One of the easiest to configure on command line is wvdial, but it's up to you to decide what you use.
Then if you happen to have one of those winmodems..it's very likely that it does not work without extra drivers, which usually don't either exist on Linux, or you have to pay something to get/use them. Some winmodems do work under Linux (read: somebody has made some sort of drivers for them), so check out HCL here at LQ, and do a web search for your modem model + Linux to find out more..
Since dialup modems are nowadays cheap (around 10$ or €, maybe some coins more for a "real" hardware modem, but it depends on the store really), I suggest that if you happen to have a winmodem that seems to be troublematic, just don't buy your weekly candies but spare the coins and buy a real hardware modem. And in case the seller doesn't know what you mean, or is not sure if it works without extra special drivers, ask for a guarantee that you can return it in case it appears to be a winmodem. It's a cheap and easy solution, and saves you a lot of headache..especially if you're going to install it more than once, maybe after a distribution upgrade or switch.
EDIT: I never quite understood how the winmodems actually made it to the market top, pushing the "real" modems aside. I've heard the stories about them being cheaper to make and such, but really it still sounds like a sick Microsoft plot; if I am to choose between a real working piece of hardware and another one which is slightly (and really only slightly in this case) cheaper and is only half of the real product, other half being the Windows only drivers, the decision would be easy. Apparently it is not for the masses.
Last edited by b0uncer; 12-20-2007 at 06:51 AM.