EXFO FPM-600 Power Meter - Manual (Page 32)

Measuring Power or Loss (FPM-600 and FOT-600)
26 FPM/FLS/FOT-600
Referencing Your Power Meter to a Source
5. Repeat the procedure for each wavelength you want to reference (if
you use auto-switching mode, the power meter automatically
references wavelengths one at a time).
Note: When using dB units, press to display the current wavelength for a
few seconds. To change this wavelength, press again while it is
displayed.
Note: Once all desired wavelengths have been referenced, do not disconnect the
Reference Test Jumper from the source port.