3Com 155 PCI manual Running the External Loopback Test

How to Use the Diagnostic Utility 6-7

Running the External Loopback Test

Run the External Loopback Test to check the integrity of the on-board transceiver and cable connectors. To run the External Loopback Test, you must use a loopback plug.

For instructions on constructing a loopback plug, see the section “Constructing Loopback Plugs” later in this chapter.

CAUTION: Do not run the External Loopback Test when the 3C975 ATMLink NIC is cabled to another device.

To run the external loopback test only, perform the following procedure:

1Insert the loopback plug into the 3Com ATMLink NIC.

2From the Select menu on the diagnostic utility main screen, select the 3C975 ATMLink NIC to be tested.

The PCI slot number or the MAC address of the NIC identifies the physical NIC being tested. The MAC address is a 12-digit hexadecimal number on the small bar code label on the component side of the NIC.

3Select Test Setup from the Test menu.

The Test Setup screen appears, as previously shown in Figure 6-2.

4Click Disable All to disable all internal tests.

5In the Test Select Box, select Ext Loopback Test.

The External Loopback Test screen appears, as shown in Figure 6-4.