EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 180)

Analyzing Traces and Events
166 OTDR
Changing the Attenuation of Fiber Sections
3. Position markers as desired to modify the attenuation value. For more
information on positioning markers, see Using Markers on page 187.
Note: The markers serve only to set the new attenuation value. Their actual
locations will not be modified.
Fiber section loss and attenuation are displayed respectively in the
Loss (LSA) and Att. (LSA) boxes.
4. Press OK to accept the modifications you have made or Cancel to
return to the events table without saving the changes.
The modified fiber sections are identified with “*” in the events table
as shown below.
Loss and reflectance
values