------------------------------------------------------------------
LED | State | Indication
-----------|--------------|---------------------------------------
On | Green On | Receiving Power
|------------------------------------------------------
| Off | Not receiving Power
-----------|--------------|---------------------------------------
Primary | Green On | Internal power supply operating.
|------------------------------------------------------
| Yellow blink | Hub is receiving power from external
| | IBM 8238 Redundant Power Unit (BUPS)
-----------|--------------|---------------------------------------
BUPS | Green On | Backup Power is available from BUPS.
|------------------------------------------------------
| Off | Backup Power not available from BUPS.
------------------------------------------------------------------
Status LEDs
------------------------------------------------------------------
LED | State | Indication
-----------|--------------|---------------------------------------
On | Green On | System OK and is currently managed by
| | management hub.
|------------------------------------------------------
| Green blink | (Expansion hub only) System OK but
| | cannot communicate with the mgmt. hub
|------------------------------------------------------
| Yellow On | In-band software download in progress,
| | or mgmt. hub setting up IntraStack
| | mgmt. connections to other hubs
| | (temporary state)
|------------------------------------------------------
| Yellow blink | Test failed, hub not operational or
| | high temperature condition.
| | Perform troubleshooting.
-----------|--------------|---------------------------------------
Beacon | Yellow On | Ring is beaconing.
|------------------------------------------------------
| Off | Ring is not beaconing.
-----------|------------------------------------------------------
Master | For future use (Green, normally On)
------------------------------------------------------------------
Speed LEDs
------------------------------------------------------------------
LED | State | Indication
-----------|--------------|---------------------------------------
16 or 4 | Green On | Indicates current speed.
------------------------------------------------------------------
Console and Aux LEDs
------------------------------------------------------------------
LED | State | Indication
-----------|--------------|---------------------------------------
Term or | Green On | Indicates terminal or SLIP mode for
SLIP | | Console or Aux port.
------------------------------------------------------------------
Stack LEDs
------------------------------------------------------------------
LED | State | Indication
-----------|--------------|---------------------------------------
Isolated | Green On | Lobe ports on this hub isolated from
| | other ports in stack.
-----------|--------------|---------------------------------------
OUT | Green On | IntraStack OUT OK.
|------------------------------------------------------
| Green blink | IntraStack OUT enabled but no data
| | signal (phantom not detected)
|------------------------------------------------------
| Yellow On | Incorrect cable connected to
| | IntraStack OUT.
| | IntraStack OUT connected to a port
| | other than IntraStack IN.
| | Mgmt. hub has not yet set up IntraStack
| | mgmt. connection to this hub
| | (temporary state).
|------------------------------------------------------
| Yellow blink | IntraStack OUT automatically disabled
| | due to beaconing.
-----------|--------------|---------------------------------------
IN | ---- | See States and Indications for
| | IntraStack Out above. Substitute In
| | for Out and Out for In.
------------------------------------------------------------------
Ports LEDs
------------------------------------------------------------------
LED | State | Indication
-----------|--------------|---------------------------------------
1 to 16 | Green On | Port enabled and attached station is
| | inserted in ring.
|------------------------------------------------------
| Green blink | Port enabled but no station inserted
| | (no phantom detected).
| | In active hubs only, station may be
| | set to incorrect ring speed.
|------------------------------------------------------
| Yellow On | Port automatically disabled due to
| | security breach.
|------------------------------------------------------
| Yellow blink | Port automatically disabled due to
| | beaconing condition or station set to
| | incorrect ring speed.
|------------------------------------------------------
| Off | Port disabled by user.
------------------------------------------------------------------
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Feel free - send a 
for any BUG on this page found - Thank you.