EXFO FTB-7000 OTDR for FTB-200 v2 - Manual (Page 231)

Analyzing Traces with the Bidirectional Analysis Application
OTDR 217
Modifying the Alignment of Unidirectional Traces
Modifying the Alignment of Unidirectional
Traces
When two unidirectional traces are opened in the bidirectional analysis
application, the span end of the B->A trace is aligned with the span start of
the A->B trace. However, you may want to modify the way traces are
aligned by redefining the span start and/or span end of one or both of the
unidirectional traces.
Keep in mind that when you modify the B->A trace, the trace is presented
in the opposite direction of the A->B trace, and so are the events.
Note: The icons used in the small table of events for the B->A trace follows the
standard for the event types (see Description of Event Types on page 297).
For this reason, they do not match the symbols used on the graph.
You can define events (new or existing) as a span start and/or span end.
You can even define a fiber span for short fibers by placing the span start
and the span end on the same event.
Span start
Span end