EXFO FTB-7000 OTDR Series for FTB-500 - Manual (Page 114)

Testing Fibers in Template Mode
100 OTDR
Acquiring Traces in Template Mode
2. Ensure that you have acquired your reference trace, entered your
comments, and created a report.
C
AUTION
Never connect a live fiber to the OTDR port without a proper setup.
Any incoming optical power ranging from –65 dBm to –40 dBm will
affect the OTDR acquisition. The way the acquisition will be
affected depends on the selected pulse width.
Any incoming signal greater than –20 dBm could damage your
OTDR permanently. For live-fiber testing, refer to the SM Live port
specifications for the characteristics of the built-in filter.