1. Blinks keyboard LEDs indicating TX and RX network packets. These programs help you monitor network traffic. They blink Scroll-Lock LED (Light Emitting Diode) when a network packet leaves the machine, and Num-Lock LED when one is received. WARNING: On some systems this has been known to render part or all of the keyboard unusable, this is rare and usually only happens on a few laptops and keyboards with overly long or old cables.. (This includes the IBM thinkpad 600 laptop, and the HP Omnibook XE2) From Debian 3.0r0 APT