This is the function key in the notebook. There is a Fn key on the lower left of the keyboard. After pressing the Fn key and the NUM key, it will switch to English letters. This is because the notebook keyboard has no keypad and needs to switch between numbers and letters.

If you access the peripheral keyboard from the usb port of a notebook or computer, because you turn on the keypad function on the original keyboard, it will cause the number to press the letter key.

Press fn+f8 in windows system to switch the keyboard mode to normal mode.