NCP>SET NODE TESTER CIRCUIT DMC-0
      NCP>LOOP NODE TESTER
         .
         .
         .
      NCP>CLEAR NODE TESTER CIRCUIT

          The first command creates a loop node name (TESTER) for
          the associated circuit, the second command initiates a
          node-level loopback test with the loop node name, and the
          third command removes the loop node name from the volatile
          database when the loopback is completed.