Chapter 11: The OptiFiber Pro OTDR Module
OTDR Results
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MARGIN: The difference between the limit and the measured
loss for each wavelength the tester used. Margin is negative if
the loss exceeds the limit.
Tap to see help for this screen.
If the results include warnings, tap to see the warnings.
If a warning caused the test to fail, tap to see the
warning. Some conditions make the OTDR test fail even when
all measurements are within the limits.
OPTICAL RETURN LOSS: This tab shows the ORL for the link.
Optical return loss is the ratio of the light from the source to
the light that the link reflects back to the source. The
reflected light is the total light reflected by the fiber and
components in the link. This includes the launch/tail cord
events, fiber segments, connectors, splices, and faults. If
launch compensation is on, this includes only the fiber
between the launch and tail connections, including the
launch and tail events. If launch compensation is off, it
includes the fiber from the OTDR port connection, including
the OTDR port connection, to the end of the fiber. The last
connector is not included, unless it has a reflectance that is
below the reflectance of the fiber, as can occur with APC
connectors.
ORL values are in units of positive decibels. A larger ORL value
shows that less light is reflected back to the source. For example,
a link with an ORL of 45 dB reflects less light back to the source
than a link with an ORL of 30 dB.
LENGTH: This tab shows the length of the fiber and the
maximum length allowed by the test limit. If the distance to
the end of the fiber does not agree at all wavelengths, this
tab shows the longest length.
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