EXFO FTB-7000 OTDR for FTB-200 v2 - Manual (Page 27)

OTDR 13
3 Getting Started with Your
OTDR
Inserting and Removing Test Modules
C
AUTION
Never insert or remove a module while the FTB-200 v2 Compact
Modular Platform is turned on. This will result in immediate and
irreparable damage to both the module and unit.
W
ARNING
When the laser safety LED is flashing, at least one of your modules
is emitting an optical signal. Please check all modules, as it might
not be the one you are currently using.