EXFO iOLM - Manual (Page 125)

Managing Results
intelligent Optical Link Mapper 119
Link View
Loopback Results
The loopback measurement is especially designed for testing cables
formed of a pair of identical fibers of an equivalent length. The measuring
time is optimized because two fibers are checked in a single
measurement.
The loopback results appear after a successful split.
You can navigate through the split measurement and the original
measurement by selecting the appropriate icon at the top of the link view.
The original measurement is analyzed and the pass/fail thresholds are
displayed for this measurement. However, there is no overall status for the
original measurement. The overall status is only for the split
measurements.