There are two ways to know exactly the loss at a point on an OTDR trace.
In the two-point method, AB two spots are taken at both ends of this point, the closer it is to this point, the better. Finally, the point to be tested is selected to obtain the loss at this point.
In the five-point method, take two points at each end of the test point, through the change of their slope, finally select the point to be tested, you can get the loss at this point.
In fact, the point selected by the OTDR cursor is calculated in this way, which is generally of little practical significance.
