Try the following procedures:
connection is not
• Verify that the connected device and the hub are both powered on and are operating
• Verify that all connections in the cable path between the hub and the connected device
• Verify that you have used the correct cable type for the connection.
• For the 100 Mbps connections, verify that you are using category 5, or better, UTP
• For the Hub 12M and Hub 24M: Verify that the port has not been disabled through a
• If the other procedures don't resolve the problem, try using a different port or a
The port has
This usually occurs because of faulty or improper cabling or a network loop. Or it may
occur because of a jabbering end node. When the condition is corrected and the normal
network traffic is restored, the port will automatically return to normal operation and the
due to excessive
Link LED will stop blinking.
A hub hardware
Self test does not complete so the Fault LED will stay on longer than 5 seconds for the
Hub 12 and Hub 24, and longer than 35 seconds for the Hub 12M and Hub 24M.
Power cycle the hub by unplugging the power cord, waiting several seconds, and then
plugging the power cord back in to the hub. If this condition persists, the hub may have
to be replaced. Contact your HP-authorized LAN dealer or HP representative for
Try power cycling the hub. If the fault indication reoccurs, the hub may have failed. Call
your HP-authorized LAN dealer, or use the electronic support services from HP to get
assistance. See the Customer Support/Warranty card for more information.
Per port security is configurable on the Hub 12M and Hub 24M only. A network device
with an address that is not in the list of authorized addresses for the port has attempted
been detected on
network communication through the hub.
Hub 12M and Hub
24M only. The
Mbps, and then a 100 Mbps-only device is connected to that port.
Locate the port with this speed mismatch condition, and unplug the cable to relieve the
condition. You may have to simply unplug cables one at a time until you see the Activity
the hub is locked
LED go back into normal flickering operation. Then, reconfigure the port for speed
up in a "jabber"
compatibility with the device before reconnecting the cable from that device.
For twisted-pair connections, in general, for connecting an end node or other MDI
device to the hub, use "straight- through" cable; for connecting MDI-X ports on other
hubs or switches, use "crossover" cable.
You can use the hub console interface, or, if you have configured an IP address on the
hub, use the web browser interface, or HP TopTools for Hubs & Switches network
management software to determine the state of the port and re-enable the port if
This condition can occur if you have configured a port to operate specifically at only 10
Diagnosing with the LEDs