Sorry, I haven't been able to find anything about a "netdragon" modem modem by googling it. Hopefully someone else has this chipset or type of Modem and can give you more info
I suspect that it may be a Winmodem. Most cheap internal modems aren't really modems at all. Instead of handling the incomming connection from the internet, they pass this function off to your CPU -- they're popular alternatives for windows users who want cheap modems, but they will only work with Windows as special drivers are required to get them working.
Some winmodems do work with Linux. Check out this link:
There's a tool on that website you can download that will allow you scan your chipset and get a better idea of what you're dealing with.
If you're going to use a modem with Linux, your best bet is to get an external modem, prferably with a serial connection Ie, plugs into your old COM port). If you do get an internal modem, make sure you get a "hardware" modem. They cost a lot more, but they have all the neccessary components built in and don't require a handoff to your CPU.