The MyChron4 series dashes are designed to save data to the MyChron Data Key rather than downloading through a direct connection to your computer's USB port.
The Data Key plugs into the CAN port on the MyChron4 and automatically saves the information from your dash. You can then take it to your computer for download, eliminating the need for a USB cable. Adding a second Data Key will let you get back on track immediately without having to wait for data to be transferred. The Data Key is also used for upgrading the firmware on your MyChron4 dash. Huge 32MB memory can save many sessions.