code: private void countFrame() {
          if (state == MTP2_ALIGNED_READY || state == MTP2_INSERVICE) {
              dCount = (dCount + 1) % 256;
              // decrement error countor for each 256 frames
              if (dCount == 0 && eCount > 0) {
                  eCount--;
              }
          }
      }
docs: Increment number of received frames decrement error monitor countor for each 256 good frames.