IBM THINKPAD 72 W DC - Manual (Page 11)

Step 3
Insert the 4-pin connector into the 4-pin power receptacle. The green light
emitting diode (LED) on the adapter box lights up when the adapter cable is
plugged into an active power source. If the LED does not light up, make sure
that the flight crew has turned on the EMPOWER system. Make sure that the
ThinkPad computer is charging by checking the power icon in the system tray
in the lower-right corner of the screen. The icon is displayed as a plug if the
computer is charging. If the computer is not charging, the icon is displayed as
a battery.
Part 1: Installation and user’s guide 1-5