how "usb mode" works?

[ahahahaah]

hello
when i launch retrofw 2.3 rc2
a popup displays and ask for a usb mode
i press the A button and a message ask to mount connect, disconnect etc..

the problème is, when i plug the usb cable to my "retro arcade" device and to my pc, then my pc doesnt recognise the connected console.

what can i do to have this usb mode?
thanks

[jayp76]

I have an RS97 rev.0 or 1 device. I tried several Mini-USB cables and is not working with all of them. It is very picky.
In my case it worked finding one that is working with my setup. Did you try different USB cables and Ports (no USB Hubs, etc..)