3Com EtherLink
EtherLink PCI Network Interface Card User Guide
Interpreting the NIC LEDs 

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Interpreting the NIC LEDs

The EtherLink PCI NICs have light-emitting diodes (LEDs), as described in the following table, that can assist with network troubleshooting.

Some LNK LED states do not apply to the AUI, BNC, SC, and ST connectors, as indicated by N/A in the table.

     

     

     

     

    Connector

    LED

    State

    Meaning

    RJ-45

    AUI

    BNC

    SC

    ST

    10 LNK (link)

    On

    If drivers are installed, the 10BASE-T connection is active.

    Yes

    N/A

    N/A

    N/A

    Yes

     

     

    If drivers are not installed, the NIC is receiving power.

    Yes

    Yes

    Yes

    N/A

    Yes

     

    Off

    Something is preventing the connection between the NIC and the hub or switch.

    Yes

    N/A

    N/A

    N/A

    Yes

     

    Blinking

    The cable polarity is reversed. Try a different network cable or contact your system administrator.

    Yes

    N/A

    N/A

    N/A

    N/A

     

    (continued)

    100 LNK (link)

    On

    If drivers are installed, the 100BASE-TX or 100BASE-FX connection is active.

    Yes

    N/A

    N/A

    Yes

    N/A

     

     

    If drivers are not installed, the NIC is receiving power.

    Yes

    Yes

    Yes

    Yes

    N/A

     

    Off

    Something is preventing the connection between the NIC and the hub or switch.

    Yes

    N/A

    N/A

    Yes

     

     

    Blinking

    The cable polarity is reversed. Try a different network cable or contact your system administrator.

    Yes

    N/A

    N/A

    N/A

    N/A

     

    ACT (activity)

    Blinking

    Network traffic is present.

    Yes

    Yes

    Yes

    Yes

    Yes

     

    Steady

    Heavy network traffic is present.

    Yes

    Yes

    Yes

    Yes

    Yes

     

    Off

    No network traffic is present.

    Yes

    Yes

    Yes

    Yes

    Yes

Viewing the NIC LEDs in the Diagnostics Program

To view the LEDs in the 3Com NIC Diagnostics program:

  1. Make sure that the NIC, the network driver, and the 3Com NIC Diagnostics program are installed.
  2. Open the Windows Start menu.
  3. Select Programs, and then 3Com NIC Utilities.
  4. Click 3Com NIC Doctor.

The 3Com NIC Diagnostics General screen appears and displays following LEDs:

    Link--lights if there is a valid connection between the NIC and the network.
    Transmit--lights if the NIC is transmitting information.
    Receive--lights if the NIC is receiving information.
    Duplex--indicates if the NIC is transmitting data across the network in half-duplex mode (half the LED lights), or in full-duplex mode (the entire LED lights).

Troubleshooting with the LEDs

If a link (LNK) LED indicates a problem, check the following:

  1. Ensure that your network hub or switch and the cable connecting to your NIC comply with the specifications appropriate for your network connection.
  2. Ensure that the hub or switch is powered on.