Key definition
PLAY : Turn On, Turn Off, Play, Pause, and Stop.
MODE: Switching Working Mode, Menu Options, Interface Switching.
NEXT : Move to Right, Forward
LAST : Move to Left, Backward
VOL+: Volume Increasing, Last Item
VOL-: Volume Decreasing, Next Item
A-B/REC: Special A -B / Recording Hot Button
EQ: When playing MP3 musical files, use this button to directly change their
sound effects without entering the option menus. Long-pressing of this
button will lock or unlock the button
POWER: Turn on or off the power
