Both of theses modems are sold at GNS. I was told that the serial port one definitely supported Linux, but they weren't sure if the usb one would work. I want to use an external modem, and would prefer the usb one if I knew it wouild work. The Trendnet site did not specifically mention it supported the TFM560U usb modem. Does anyone know the answer to this or where an inexpensive external modem is available? TRENDnet® TFM560U External 56K V.90 USB Fax/Data TRENDnet® TFM560X External 56K V.90 Serial Fax/Data Thanks, lyle wood