Connecting the Hub Power Cord and Powering On the Loop
35
Table 3-1 outlines LED activity when the hub is powered on.
Note:
A cable connected to a port does not constitute a valid link unless its other end
is connected to a device.
If the LEDs are not functioning this way, check the appropriate connection: check
the cable seating, Ethernet configuration if applicable, and system configuration.
Observe the following warnings for fiber optic cabling.
Warning:
Never look into the end of a fiber optic cable to confirm that light is
being emitted (or for any other reason). Most fiber optic laser wavelengths (1300
nm and 1550 nm) are invisible to the eye and cause permanent eye damage.
Shorter wavelength lasers (for example, 780 nm) are visible and can cause
significant eye damage. Use only an optical power meter to verify light output.
Warning:
Never look into the end of a fiber optic cable on a powered device
with any type of magnifying device, such as a microscope, eye loupe, or
magnifying glass. Such activity causes cause a permanent, irreversible burn on the
retina of the eye.
3. If the green power LED indicates that the hub is ready, power on the nodes that are
not already powered on. The LED for each hub port they are connected to should be
green.
If the port LEDs do not function this way, check the connections to the devices.
Observe the fiber optic cabling warnings on this page.
Table 3-1
LED Activity at Hub Power-On
Purpose
Location
Color or State
Meaning
Power
Left of 10-Base-T socket; top
(green)
On
Power is applied
Network
Left of 10-Base-T socket; bottom
(yellow)
Unlit
Low intensity, steady
High intensity, blinking
No connection to network
Link up
Network activity
Fibre channel
Front panel
Yellow
Green
Port is bypassed: cabled device is
not powered on
Link is established
