Any deviation from the normal operating point of the receiver for a given line length and cable may be an indication of a fault condition. By establishing a set of baseline characteristics when the link is first established, and then monitoring any changes over time, it becomes possible to predict a fault condition is about to occur before it results in the link being dropped. For example, an abnormally low Signal to Noise Ratio (SNR) might still be sufficient to support an acceptable Bit Error Rate (BER) but is probably an indication of excessive signal attenuation, crosstalk, or noise somewhere in the signal path.