dell latitude c640

PCMCIA is 5V ISA BUS. There are CARDBUS 3.3V usb2 adaptors that work fine.

Make sure you get one with an NEC Chipset so that you can use native windows drivers.

There is a power limitation though that may require you to add an External power supply to the

Cardbus card.

This one comes with the external power supply.

BELKIN COMPONENTS USB 2.0 Laptop Card 2 port CardBus USB ... - Dell <ADMIN NOTE: Broken link has been removed from this post by Dell>

Highlights Offers Plug-and-Play setup, and works seamlessly with Windows 98SE, 2000, Me, or XP Adds two 480 Mbps, USB 2.0 ports to your Laptop, quickly and easily Works with any 32-bit, type II CardBus slot Can connect with a Belkin USB 2.0 hub Overview A quick installation provides two 480Mbps ports - simply slide the card into your CardBus Card Type II slot. The Card offers Plug-and-Play setup and you can instantly connect next-generation scanners, printers, high-speed storage devices, and video cameras. Linking the Card with a Belkin USB 2.0 hub lets you daisy-chain up to as many as 127 USB 1.1 and 2.0 devices to your laptop. Manufacturer Part# : F5U222V1 Dell Part# : A0918540