What is the Fn Lock icon used for and how do you turn it off and on?

The Fn key and Fn Lock key serve specific functions on certain keyboards, particularly laptops and some standalone keyboards. These keys help manage the function keys (F1 through F12) to provide additional controls on compact keyboards. The Fn key functions similarly to the Shift key, where you hold it down to access alternate actions on function keys.

In most cases, these alternate actions include media controls. Fn Lock operates like the Caps Lock key; pressing it once activates the alternate mode, and pressing it again deactivates it. While a dedicated Fn Lock key is less common, some keyboards may still have this feature. On keyboards without a separate Fn Lock key, you can toggle the Fn key using combinations like Fn and Shift or Fn and Esc.

To change the default behavior of the function keys, you can adjust settings in your BIOS. Restart your computer, enter the BIOS by pressing the designated key (often Function, F2, or Delete), and look for settings like Function Key Mode or Action Key Mode. Enabling or disabling this setting will determine whether the function keys operate in their standard mode or alternate mode by default, though which setting is which depends on your specific system.

Some devices may also offer configuration software to adjust these settings without accessing the BIOS.