Cisco Systems 274 Manuale Utente

The Ethernet link status LED is on when the Ethernet controller receives 
a link pulse from the switch. If the LED is off, there might be a defective 
connector or cable or a problem with the switch.

The Ethernet activity LED is on when the Ethernet controller sends or 
receives data over the Ethernet network. If the Ethernet activity LED is 
off, make sure that the switch and network are operating and that the 
correct device drivers are installed.

Make sure that you are using the correct device drivers that are supplied with 
your device and that the device drivers on the client and the device are using 
the same protocol.

Check for operating system-specific causes for the problem.

 lists solutions to 10/100/1000-Mbps Ethernet controller problems.

Ethernet link status 
LED does not work.

Check the following: 

Make sure that the switch to which the WAVE appliance is connected is 
powered on.

Check all connections at the Ethernet controller and the switch.

Use another port on the switch.

If the switch does not support autonegotiation, manually configure the 
Ethernet controller to match the switch.

If you manually configured duplex mode, make sure that you also 
manually configure the speed.

Reseat or replace the adapter.

The Ethernet activity 
LED does not work.

Check the following: 

The network might be idle. Try sending data from this device.