EXFO FTB-7000 OTDR for FTB-200 v2 - Manual (Page 90)

Testing Fibers in Fault Finder Mode
76 FTB-7000 Series
Acquiring Traces in Fault Finder Mode
3. From the Port list, specify to which port you connected your fiber (for
C fiber, select 50 μm and for D fiber, select 62.5 μm).
4. Press Start or from the keypad. If the first connector check
feature is enabled, a message will appear if there is a problem with the
injection level (see Enabling or Disabling the First Connector Check for
Fault Finder on page 85).