An Ethernet transceiver includes physical-layer (PHY) circuitry and a signal-loss detector. The PHY circuitry is configured to receive a signal from a peer transceiver, to process the received signal in a series of digital PHY-level processing operations, and to output the processed signal for Medium Access Control (MAC) processing. The signal-loss detector is configured to receive, from the PHY circuitry, a digital version of the received signal, and to detect a signal-loss event based on an amplitude of the digital version of the received signal.