NUU Mobile NU3S - USB Connection Modes; Charging Mode; Camera Mode; Media Device Mode

30
Charging Mode: In this mode, the phone will only charge on a
computer USB port, not communicate with the computer. This is the
default setting.
Camera Mode: When connected in this mode, the phone appears to
the computer as a camera.
Media Device Mode: When connected in this mode, the phone
appears to the computer as a regular flash drive. You will have more
access to folders and data on the phone.