Lenovo K6 NOTE User Manual page 6

Media device (MTP): Select this mode if you want to transfer any media files on Windows,
or use Android File Transfer on Mac (see www.android.com/filetransfer).
Camera (PTP) : Select this mode if you want to transfer photos using camera software, or
transfer any files on computers that don't support MTP.
MIDI : Select this mode if you want MIDI -enabled applications on your phone to work with
MIDI software on the computer.
Charge only: Select this mode to stop all USB functions, speed up USB charging and
decrease power consumption.