EXFO OTDR 2 - Manual (Page 43)

Preparing Your OTDR for a Test
OTDR 35
Setting Macrobend Parameters
Setting Macrobend Parameters
Your unit can locate macrobends by comparing the loss value of an event
at a given wavelength (for example, 1310 nm) with the loss value at the
same location with another wavelength (for example, 1550 nm).
The unit will identify a macrobend when comparing two loss values if:

Of the two loss values, the greater loss occurred at the greater
wavelength.
AND

The difference between the two loss values exceeds the defined delta
loss value. The default delta loss value is 0.5 dB (which is suitable for
most fibers), but you can modify it.
You can also disable macrobend detection.
Note: Macrobend detection is only possible with singlemode wavelengths.
Filtered wavelengths or port with only one wavelength are not available for
macrobend detection.
For information on how the information about macrobends is available
after an acquisition, see Summary Tab on page 96.