The difference between the USB cables are the non-USB ends. One of the cables has an auxiliary cable end, this cable is the serial data cable, it is used for connecting the FROG-4000 to the Ellvin GC software to run the FROG-4000 live with the software. The other cable has a micro USB connector on one end, this cable is used for extracting data files from the Frog’s memory. Watch a video about how to connect your Frog to the Ellvin GC software using the serial data cable.