EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 147)

Analyzing Traces and Events
OTDR 133
Event Pane
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Att.: Attenuation (loss/distance) measured for each fiber section.
Note: The attenuation value is always presented in dB per kilometers even if the
distance units you selected are not the kilometers. This follows the
standards of the fiber-optic industry that provides the attenuation values in
dB per kilometers.
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Cumul.: Cumulative loss from the trace span start to span end; the
running total is provided at the end of each event and fiber section.
Cumulative loss is calculated for the events displayed in the events
table, excluding those that are hidden. For a more accurate link loss
value, refer to the loss measurement displayed in the Trace Info pane.
If you want to modify events or fiber sections, see Changing the Loss
and Reflectance of Events on page 158, Inserting Events on page 162,
and Changing the Attenuation of Fiber Sections on page 165.