Asus X53SD - Manual (Page 50)

50 Notebook PC User Manual
Number Lock Indicator
Indicates that number lock [Num Lk] is activated when lighted.
Number lock allows some of the keyboard letters to act as
numbers for easier numeric data input.
Capital Lock Indicator
Indicates that capital lock [Caps Lock] is activated when lighted.
Capital lock allows some of the keyboard letters to type using
capitalized letters (e.g. A, B, C). When the capital lock light is OFF,
the typed letters will be in the lower case form (e.g. a,b,c).