Chapter 6: Troubleshooting
Twisted-Pair Port Link LED Is Off
When a twisted-pair port on the switch is connected to a properly operating end node, the Link LED for the port should be on. If a Link LED is off, do the following:
Verify that the switch is not set to the power-saving mode by pressing the ecoFriendly push-button on the front panel. Refer to “AT-9000 Series Gigabit Ethernet Switches” on page 19 for the ecoFriendly push-button location.
Verify that the end node connected to the port is powered on and is operating properly.
Check that the twisted-pair cable is securely connected to the port on the switch and to the port on the end node.
Make sure that the twisted-pair cable does not exceed 100m (328 ft.).
Verify that you are using the appropriate category of twisted-pair cable. For information, refer to Table 1 on page 27.
Determine if a crossover cable is required. Because the twisted- pair ports feature auto MDI/MDI-X, you should be able to use a straight-through cable, regardless of the type of device you connect to a port. However, if you disable Autonegotiation on a port and set a port’s speed and duplex mode manually, the port defaults to MDI-X. Disabling Autonegotiation may require manually configuring a port’s MDI/MDI-X setting or using a crossover cable.
Make sure that the operating parameters of the port on the switch (speed, duplex, or Autonegotiation) are compatible with the end node to which the port is connected.
