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How to Perform Loopback Testing in UNIX and Linux Using the DPA Interface

The DPA program utility is provided with most AccelePort and RealPort drivers for most UNIX flavors. To test port integrity place the loopback plug into the corresponding port. The loopback plug is shipped with Digi products and resembles a "dead-end" connector or simply a connector without a cable.


  1. From the SCO OpenServer. UnixWare, or Solaris (AccelePort driver only) root prompt, type:


          From the root prompt of AIX (RealPort only):


          From the root prompt of Linux:


          Digi Neo/ClassicBoard:




  1. Press [Enter] while highlighting the desired Digi product entry. For Xem, C/X or EPC/X products you will be required to arrow and highlight the corresponding module or concentrator [AC] reference followed by the [Enter] key.


  2. The next screen represents the port signal activity for port 1 or channel 1. Use the right and left arrow keys to cycle through the ports/channels until the desired port/channel number which has the loopback plug inserted is displayed in the upper right corner of the rectangle.


  3. Press the letter T to start the loopback test.


The testing will run continuously until a key is pressed to stop it. A failure message would indicate a possible hardware problem with the product, in which case you should contact Digi International Technical Support.
Last updated: Aug 23, 2018

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