EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 123)

OTDR 109
8 Customizing the Application
You can customize the appearance and behavior of your OTDR application.
Selecting the Default File Format
You can define the default file format the application will use when you
save your traces.
By default, traces are saved in native (.trc) format, but you can configure
your unit to save them in other formats.
The available formats are the same as those presented in Saving a Trace in
a Different Format on page 199.
If you select ASCII or ASCII+ formats, file autonaming (see Naming Trace
Files Automatically on page 50) will not work when you save your files.
Since the application does not support these formats, it will always keep
the same file name and consider that the trace has never been saved.