Linux modem

I’m using Ubuntu Hoary Hedgehog 5.04. I had already installed gnomeppp and set up a dial-up connection but I’m still having trouble with the modem (internal). My modem is listed on the Device Manager, but when I click autodetect modem I receive a message “modem not found.” The first modem I have tried was conexant–I don’t know the name of the manufacturer–then I tried Cnet but still, it was not detected. Should I install a driver for my modem to be detected?

Suggestions are greatly appreciated. Thanks!