Dell Latitude 12 Rugged Extreme (7204, Early 2014) - Manual (Page 57)

Device Status Lights
Icon Description
Turns on when you turn on the computer and blinks when the computer is in a power
management mode.
Turns on when the computer reads or writes data.
Turns on steadily or blinks to indicate battery charge status.
Turns on when wireless networking is enabled.
Battery Status Lights
If the computer is connected to an electrical outlet, the battery light operates as follows:
Alternately
blinking amber
light and green
light An unauthenticated or unsupported non-Dell AC adapter is attached to your
laptop.
Alternately
blinking amber
light with
steady green
light Temporary battery failure with AC adapter present.
Constantly
blinking amber
light Fatal battery failure with AC adapter present.
Light off Battery in full charge mode with AC adapter present.
Green light on Battery in charge mode with AC adapter present.
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