Well, thank you for your reply , it's clear
when looking to this item
http://www.mecanique.co.uk/products/usb/easyhid.html
could you tell me if I'm right ?

PIC (same in this example) is connected to a PC through the USB interface

Do you think that I will be able to see a "TEXT FILE" in the PC hard disk
and get the datas with a USBread command (or something else)

If it is possible, I can prepare the TEXT file with a simple method
and feed my PIC (with OSD program imbedded) ?

thanks in advance

Francois F1CHF