Long press means pressing key more than or equal 2 seconds; short press means
pressing key less than 2 seconds.
Enter numbers, letters, and some special characters.
In standby mode, press and hold  to access your voice mail
The key "0" can be used to input the "+" for international calls and to
input space. Under the English input methods, the key "1" can be
used to input the frequently used symbols or items quickly.
In standby mode, long press this key to lock the keypad; short press
this key to Input the symbol "*".
In standby mode, long press this key to enable or disable the
Meeting mode; short press this key to Input the symbol "#".
Plug the travel adapter into the charger connector.
Before using headset, pull in the headset to this jack.