HP ProBook 640 G2 Notebook PC, HP ProBook 645 G2 Notebook PC, HP ProBook 650 G2 Notebook PC and HP ProBook 655 G2 Notebook PC - Maintenance and Service Guide
Press fn+function key Description
Decreases the screen brightness incrementally as long as you hold down the key.
Increases the screen brightness incrementally as long as you hold down the key.
Decreases speaker volume incrementally while you hold down the key.
Increases speaker volume incrementally while you hold down the key.
Mutes the microphone.
16 Chapter 2 External component identication