EXFO OTDR 2 - Manual (Page 61)

Testing Fibers
OTDR 53
Setting the Automatic Acquisition Parameters
5. If you want to use the optimized range feature, proceed as follows:
5a. Tap the button.
5b. Under Advanced Parameters, select the Use optimized range
box.
5c. Tap OK to return to the main window.
6. Tap Start to launch the acquisition.