A method tests a subscriber line. The method includes providing a classifier
to
predict a performance characteristic of the line based at least in part on a value
of an auxiliary variable. Each value of the auxiliary variable represents a property
of the line. The method also includes performing electrical measurements on the
subscriber line, using the measurements to predict a value of the auxiliary variable,
and predicting the performance characteristic of the line. The act of predicting
the characteristic applies the classifier to the predicted value of auxiliary variable.
