Table 8. Status indicators
Indicator Meaning

1 Wireless LAN

status

Green: The wireless LAN feature is on, and the radio link is

ready for use.
Blinking green:
Data is being transmitted.

2 Wireless PAN

status

R

or

Green: Wireless PAN (Bluetooth wireless or Wireless USB) is

operational. This indicator is on when Wireless PAN is
on and not in suspend mode.

3 Wireless WAN

status

Green: The wireless WAN is on, and the radio link is ready for

use.
Blinking green:
Data is being transmitted.

4 Num lock

Green: The numeric keypad on the keyboard is enabled. To

enable or disable the keypad, press and hold the Shift
key, and press the NumLk (ScrLk) key.

5 Caps lock

Green: Caps Lock mode is enabled. To enable or disable Caps

Lock mode, press the Caps Lock key.

6 Drive in use

Green: Data is being read from or written to the hard disk

drive, the diskette drive, or the drive in the Serial
Ultrabay Slim device or Serial Ultrabay Enhanced
device. When this indicator is on, do not put the

computer into standby mode or turn off the computer.

Note: Do not move the system while the green drive-in-use light

is on. Sudden physical shock could cause drive errors.

7 Power on

Green: The computer is on and ready to use. This indicator

stays lit whenever the computer is on and is not in
standby mode.

8 Battery status

Green: The battery is charged between 80% to 100% of the

capacity, and being discharged between 0% to 80% of
the capacity.
Blinking green:
The battery is charged between 20% to 80% of the
capacity, and being charged.
Orange:
The battery is charged between 5% and 20% of the
capacity, and being discharged.
Blinking orange (slow):
The battery is charged between 5% to 20% of the
capacity, and being charged.
Blinking orange (rapid):
The battery is charged between 0% to 5% of the capacity.

9 AC power

status

Green: The computer is connected to the ac power supply.

10 Standby status

Green: The computer is in standby mode.

Blinking green:
The computer is entering standby mode or hibernation
mode, or is resuming normal operation.
52 ThinkPad T400 and R400Hardware Maintenance Manual