Asus T304U E-Manual page 19

Power (DC) input port
Insert the bundled power adapter into this port to charge the
battery pack and supply power to your Tablet.
WARNING! The adapter may become warm to hot while in use.
Do not cover the adapter and keep it away from your body while
it is connected to a power source.
IMPORTANT! Use only the bundled power adapter to charge
the battery pack and supply power to your Tablet.
Two-color battery charge indicator
The two-color LED provides a visual indication of the battery's
charge status. Refer to the following table for details:
ASUS Tablet and ASUS Keyboard Dock E-Manual 19