EXFO FTB-700 for FTB-1 - Manual (Page 282)

Maintenance
274 FTB-700 Series
Verifying Your OTDR
To determine the measurement range (singlemode models only):
1. Connect the OTDR as indicated below. Other configurations are
possible, but the fiber should have several sections longer than 2 km,
with no loss greater than 8 dB and with the average attenuation not
exceeding 1 dB/km. A variable attenuator will be used to adjust the loss
in the span.
One or several non-reflective events with a nominal loss of 0.5 dB
should be present. Join a series of fiber reels between the OTDR and
the variable attenuator for a length of approximately 20 km. Join
another series of reels to complete the fiber length needed for the test.

Ensure that the OTDR port and connectors are correctly cleaned.

Make sure the fiber settings are accurate (IOR, Helix factor, and
RBS).
1 to M reels of fiber
( Add as needed )
OTDR
2 km or more
Fiber End
Measured
Fiber Event
4 km min 2 km or more
20 km
Variable attenuator
2 km or more 2 km or more
Fiber end 1 to M reels of fiber
(Add as needed)
4 km min.
Measured fiber end