This driver is for a US Robotics 0727 modem (aka 3CP3298-DEL and product ID 83329800). It's a US Robotics/3Com OEM modem made for Dell. Windows will say the modem is a "PCI Serial Controller" when you first install the card. Follow the instructions under step 7 of the Installation section of the setup docs included with this driver. After a lot of searching - this is the driver that works for me! Good luck!