3Com Corporation
                EtherDisk Diskette for the EtherLink II Adapters
                   Diagnostic Program Instructions Summary


  Overview
  --------

  The diagnostic program tests the EtherLink II adapter to make sure that it
  is installed correctly and functioning properly in your computer.  

  -  The Group 1 tests check the physical components, connectors, and 
     circuitry of the adapter.  They require only that the adapter be 
     installed in the computer.  

  -  The Group 2 tests check the adapter's ability to transmit data on the 
     network.  They require that the adapter be connected to a loopback plug 
     (coax version only) or to a network.  

  -  The Group 3 tests check the adapter's ability to correctly transmit and 
     receive data over the network.  They require that the adapter be 
     connected to a network on which an echo server has been set up.


  Starting the Diagnostic Program
  -------------------------------

  The computer containing the EtherLink II adapter to be tested must be 
  running DOS with no network drivers or memory managers loaded.  

  NOTE:  If this computer is an operating server, notify all users of the 
         server to save their work and log out from the network.  The 
         diagnostic program disrupts the normal operation of server and 
         workstations, so work that is not saved may be lost.  

  There are two ways to start the diagnostic program:

  1.  Insert the EtherDisk diskette and type MENU at the prompt.  Select
      the option "Diagnostic and Troubleshooting Information" from the main 
      menu.  Use the appropriate program for either the coax or the 
      twisted-pair version of the adapter.

	  If only one diagnostic program is listed, use it for either version of
      the adapter.  For example, the EtherLink II and EtherLink II TP adapters
      use the same diagnostic program.

  2.  Type the following command from the root directory of the EtherDisk
      diskette:
  
      3C503 [/B:I/O BASE ADDRESS] [/S]

      The brackets indicate that the /B and /S switches are optional.

      If the /B switch is omitted, the diagnostic program will search through 
      the possible I/O base addresses to find an EtherLink II adapter to test.
      Use the /B switch to specify a particular EtherLink II adapter to be 
      tested in a computer with multiple EtherLink II adapters installed.  
      Use the I/O base address of the adapter to be tested for the I/O BASE 
      ADDRESS.

      If the /S switch is specified, the diagnostic program will test DMA
      transfers	using the single-byte mode.  If the switch is omitted, DMA
      demand mode is used.


  Using the Diagnostic Program
  ----------------------------
  When you use the diagnostic program, you will be asked to specify a DMA
  channel, interrupt level, and transceiver type.  Select a DMA channel and
  interrupt level that do not conflict with those of any other peripherals
  installed in the computer.  See the SYSRESRC.TXT file in the \README
  directory on the EtherDisk diskette for a list of system resources used by
  other common peripherals. The ON-BOARD transceiver (BNC or RJ-45 connector) is the 
  default setting.  EXTERNAL should be selected if an external transceiver 
  (AUI connector) is being used.

  The menus and forms that make up the diagnostic program will guide you
  through testing your EtherLink II adapter.  The following keys can be used:

     Key              Function
     ---              --------

     [Up-arrow]       Moves highlight within menus and forms
     [Down-arrow]

     [Enter]          Selects highlighted item
     [Return]

     [F1]             Gives help information about the highlighted item

     [Esc]            Returns to previous menu or form
                      Stops a test
                      Stops echo server operation


  If the adapter fails the diagnostic program, see the TROUBLE.TXT file in the
  \DIAG directory on the EtherDisk diskette for troubleshooting procedures.


  Further Information
  -------------------

  For more information about the diagnostic program and how to use it,        
  refer to the appropriate adapter guide.  The SUPPORT.TXT file in the
  \README subdirectory on the EtherDisk diskette provides information about
  obtaining product support for the EtherLink II adapter.  For more 
  information about jumper settings for the twisted-pair adapters, refer to 
  the TPOPTS.TXT file in the \README subdirectory.

  The TROUBLE.TXT, SUPPORT.TXT, and TPOPTS.TXT files can be automatically 
  displayed and printed from the Menu Program.


         (%VER  Diagnostic Program Instructions Summary v3.4a)