Beginning with Firmware V 5,0 for the OptiFiber Pro, we introduced a new condition where the OptiFiber Pro will report a result for the reflectance value of all Loss or Gainer Events. Previously, events with very low reflectance, for example, APC connections and splices, could have had reflectance reported as “N/A”
This result caused confusion and now it has been changed so that now a reflectance value is reported for any Loss or Gainer event. If the reflectance is too low for the OptiFiber Pro to measure, the result is reported as, “< #Value#.” In many cases, this will have no impact. If there is a reflectance limit configured, the reported value will be compared to the limit to give a pass or fail result.
There is an implication to this change that does apply in certain situations. As the Pulse Width is increased, the measurable reflectance value decreases. If you are using a larger pulse width, such as 300ns, the lowest reflectance value OptiFiber Pro can report is -64dB at the 1310 wavelength. If you have a reflectance limit set for your APC connections of -65dB, you will get a failing result. To avoid this, use a Manual OTDR Test setup for the OptiFiber Pro with configured pulse widths short enough to measure values less than the reflectance limit.
The chart below details the approximate reflectance values that can be measured with different pulse widths.
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