3Com Corporation
                EtherDisk Diskette for the EtherLink II Family 
                                Troubleshooting



 If the EtherLink II adapter diagnostic tests fail, the adapter might not be
 defective.  Check the following:

 1.  Make sure the adapter is completely seated in its slot.  Review the
     installation instructions in the appropriate adapter guide. 

 2.  If you are running the Group 2 tests, make sure the adapter is securely
     connected to a loopback plug (coax version only) or to a properly cabled
     network.

 3.  If you are running the Group 3 tests, make sure the adapter is securely
     connected to a properly cabled network and an echo server is set up on 
     the network.

 4.  Make sure that the jumper settings do not conflict with any other 
     peripheral or software program installed in the computer.  Jumper 
     settings to check are the I/O Base Address, Interrupt Level, DMA
     setting, and Memory Base Address.  For a list of system resources
     commonly used by other peripherals, select  "Miscellaneous Information"
     from the main menu, then "System Resources" from the information 
     submenu. 

 5.  Make sure that the transceiver type selected while running the diagnostic
     program is correct.
   
 6.  Running tests while connected to an active network can cause intermittent
     failures.  These failures can be avoided by using an inactive network on
     which only the computer being tested (and an echo server if running the
     Group 3 tests) are connected.

 7.  If you installed an EtherLink II TP adapter, check the LEDs on the back
     plate of the adapter.  The yellow (ACT) LED is on when there is data  
     transmission activity on the adapter.  This light will go on during
     the Group 2 and Group 3 tests.  The green (LNK) LED will be on when there
     is a correct connection between the adapter and the hub.  If the link
     pulse jumper is in the OFF position, the green LED will be on whether or
     not there is a connection.

 8.  If you installed an EtherLink II TP adapter, make sure that the settings
     for the following jumpers are correctly configured for the hub:
    
        RECEIVE THRESHOLD
        DC SIGNAL
        LINK PULSE
        EQUALIZATION
        WIRE IMPEDANCE
        TRANSMIT LEVEL
   
     For information on setting these jumpers, select "Miscellaneous 
     Information" from the main menu, then "Twisted-pair Options" from the 
     information submenu.

 9.  The slot in the computer may be defective.  Install the adapter in 
     another slot and run the tests again.

 10. The computer in which the adapter is installed might be defective.
     Install the adapter in a known functioning computer and run the tests
     again.

 11. The loopback plug you are using might be defective.  Try a different
     loopback plug.

 12. Replace the failed adapter with a known working EtherLink II adapter, 
     with the same jumper settings.  If the second EtherLink II adapter fails,
     something is probably wrong with the test environment, not with the 
     adapter.





                   (%VER  Troubleshooting v2.0b)