EXFO FastReporter 2 - Manual (Page 165)

Working with OTDR Files
Post Processing Software 155
Setting Span Positions with Absolute Lengths
Setting Span Positions with Absolute Lengths
The application allows you to set the span start and span end positions
using definite values.
To set the span positions:
1. In the Measurements window, select the measurements for which you
want to set the span.
2. On the Measurement menu, click OTDR and select Set Spans by
Distance.
3. Set the launch fiber length as required. Once you set the launch fiber
length, the application updates the span start position and span length
value based on the new position of the span start. If no event is present
at the new position of the span start, it automatically creates a new
event.