HP EliteBook 820 User Manual page 24

Component
(2)
(3)
(4)
(5)
12 Chapter 2 Getting to know your computer
Speakers (2)
Wireless button
Volume mute button
Fingerprint reader (select models only)
Description
To learn more about your power settings: Select Start > Control
Panel > System and Security > Power Options.
Produce sound.
Turns the wireless feature on or off but does not establish a
wireless connection.
Mutes and restores speaker sound.
Allows a fingerprint logon to Windows, instead of a password
logon.