Everything I have read says the USB settings should be easily located in the pull-down notifications area, located under "Ongoing". I am operating a stock S3 with version 4.1.2. I have no roots or changes. When I connect my phone to a PC via the USB cable, it charges the phone and that's it. I cannot access the phone via my PC. My PC does not prompt me to transfer files, sync, etc. It literally acts as if the phone is not connected. I have checked every setting I can find and don't see any options for the USB mode. I have tried it connected to the PC and disconnected from the PC. I have tried resetting it. I even tried it in a box, with a fox in sox. I also tried the "HELP" section of this forum but haven't received a response.