A system and method is disclosed for monitoring the quality of a data link in a 100 Mb Ethernet physical layer device. A link quality monitor detects operational values of data link parameters such as digital equalizer C1 coefficient, digital adaptive gain control, digital base line wander, recovered clock long-term frequency offset, and recovered clock frequency control. When an operational value of a data link parameter exceeds a high or low threshold value, the link quality monitor sends a drop link signal to cause the current data link to be dropped and a new data link established.