Lenovo ThinkPad T420si (English) User Guide - Page 20

For more information about how to use the camera, refer to "Using an integrated camera" on page 60. 11 ThinkLight You can use your computer under less than perfect lighting conditions. To illuminate the keyboard, turn on the ThinkLight® by pressing Fn+PgUp. To turn it off, press Fn+ PgUp again. 14 Built-in stereo speaker (right) 22 Built-in stereo speaker (left) The stereo speakers are built into your computer. For details, refer to the instructions in "Volume and mute buttons" on page 32. 15 Forward and Back keys The Forward and Back keys on your keyboard near the cursor-control keys are used with your Internet browser, such as Internet Explorer®. They function like the forward and back arrows in the browser that move you back and forward to pages you have viewed in the order that you opened them. 16 Fingerprint reader Some models have a fingerprint reader. The fingerprint authentication technology enables you to use your fingerprint to start the computer and enter the UEFI Setup Utility. For details, refer to the instructions in "Using a fingerprint reader" on page 79. 17 Bluetooth antenna Your computer has Bluetooth Integrated Bluetooth features. 20 Fn key Use the Fn key to take advantage of ThinkPad® functions, such as turning on the ThinkLight. To use ThinkPad functions, press Fn + the required function key marked in blue. 21 CapsLock indicator The indicator of CapsLock is located on the CapsLock key. For more information about CapsLock indicator, see "System-status indicators" on page 11. 4 User Guide