EXFO IQS-12002B Calibration System - Manual (Page 79)

Calibration Methods
Calibration System 75
FTB-7000D and FTB-7000B-B OTDR Modules
EXFO determines the true central wavelength and distribution for the type
of lasers used in an OTDR family (e.g., FTB-7000D, AXS-100). The reference
distance used in the OTDR calibration takes into account the true central
wavelength of the OTDR family. The following table is an example for an
OTDR of the FTB-7000D family.