Why do errors and alarms appear on my TSU Router Module or Nx56/64 port when the Network port is set to D4/AMI

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    Article ID: 1514
    Q&A

     

     

      Why do errors and alarms appear on my TSU Router Module or Nx56/64 port when the Network port is set to D4/AMI?


     

    Q:

    Why do errors and alarms appear on my TSU Router Module or Nx56/64 port when the Network port is set to D4/AMI?

     

     

    A:

    If AMI line coding is used, the maximum rate allowed per channel (DS0) is 56k. Otherwise the 12.5% ones density required for proper T1 operation may not be met, which will result in T1 errors and alarms.  Utilizing a DSO rate of 56k will force the least significant bit in each corresponding channel mapped to the router or Nx56/64 port to a one in order to satisfy the 12.5% ones density requirement.  This problem is dependant only on the line coding (AMI) and not the T1 frame format (D4).  Whenever possible B8ZS line coding should be used in data applications instead of AMI.  AMI is best suited for analog voice applications, and not for data.