EXFO FTB-3930 MultiTest - Manual (Page 39)

Measuring Optical Return Loss
Multifunction Loss Tester 33
Performing and Saving ORL Measurements
5. Connect one end of a patchcord to the F
AS T ES T SM port of your unit
leaving the other end unconnected.
6. Perform an ORL reference as follows:
Note: During the reference, the patchcord end should remain in the air;
reflections occurring at a fiber-to-air interface correspond to a constant of
14.7 dB.
Press ORL Reference.