EXFO OTDR 2 - Manual (Page 108)

Analyzing Traces and Events
100 OTDR
Events Tab
If an asterisk appears next to the event symbol, the tooltip will also show
“(*:Modified)” to indicate that this event has been modified manually.
If the asterisk appears next to the event number, “(*:Added)” will appear to
indicate that this event has been inserted manually.
For each item listed in the events table, information is displayed:

No.: Event number (a sequential number assigned by the OTDR test
application) or, in parentheses, the length of a fiber section (the
distance between two events).
Various symbols are also used to describe different event types. For a
more detailed description of symbols, see Description of Event Types
on page 185.

Pos./Length: Distance between the OTDR and the measured event or
between the event and the beginning of the fiber span.

Loss: Loss in dB for each event or fiber section (calculated by the
application).

Reflectance: Reflectance measured at each reflective event along the
fiber.

Att.: Attenuation (loss/distance) measured for each fiber section. The
Att.. column is only visible when the fiber sections are displayed. For
more information, see Setting Event Table and Graph Display
Parameters on page 67.
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.