If you are a GSM network user , if you use GNU/Linux and if you have a 3G modem that doesn't work on your system, then you should check out Sakis3G.
I don't personally have that problem, but while looking for information for a friend I came across this simple script (Sakis3G) , which is basically able to identify your environment (kernel, distribution, modem, operator, desktop environment) and provide you with a data connection in seconds.
Sakis3G can configure a USB or Bluetooth modem , and the website states that it may work on CDMA networks . It also has the country codes for over 44 countries in its database, and if your country isn't listed, the website provides information on how to add it.
You can download it from this link for i386, amd64, armv4t and armv5t or both.