I have a TRENDnet TFM-560U external dialup modem that I am running on my laptop with Windows Vista Basic. I can connect to the internet using AOL (and I've tried NetZero) and after 15-20 minutes the internet gets disconnected. I do not have call waiting and have had my phone lines checked and they are in working order. What is kicking me off the internet and how do I fix it?

Computers & Internet - Trendware - 56K USB Fax Modem High Speed (DHTFM560U)