It's a piece of avionics http://www.avidyne.com/EX5000/default.shtm
that requires data uploads to keep its geographic and navigational databases current, and also dumps data from an engine monitoring application.
Both are done by plugging in the zip drive to the units front-panel usb port before powering up. It sees the drive and, if it has properly formated data on it, goes into its upload mode or, if it's blank, goes into its data dump mode. There is no way to access these routines otherwise. I've tried plugging in a flash drive instead, and the unit behaves as if nothing has been inserted.