Patent ID: 8169893

Claim:
A method of operating an electronic device having data communications ports, the method comprising: monitoring a particular Physical Coding Sublayer (PCS) status signal from Physical Layer (PHY) circuitry of a first data communications port of the electronic device, each data communications port including respective PHY circuitry to provide Physical Layer network functionality to the electronic device, the particular PCS status signal having (i) a PCS_OK value when the first data communications port is operating reliably in data mode and (ii) a PCS_NOT_OK value when the first data communications port is not operating reliably in data mode; generating a link status signal indicative of a status of a link of the first data communications port, the link status signal having a LINK_UP value indicative of the link being up and a LINK_DOWN value indicative of the link being down; detecting a transition event while monitoring the particular PCS status signal, the transition event involving the particular PCS status signal initially having the PCS_OK value and transitioning to having the PCS_NOT_OK value; and in response to detection of the transition event, outputting an electronic warning indication to enable failover from the first data communications port to a second data communications port, wherein detecting the transition event includes (i) identifying a change in the particular PCS signal from the PCS_OK value to the PCS_NOT_OK value, (ii) after identifying the change, waiting a predetermined amount of time, and (iii) concluding that the transition event has occurred when the particular PCS status signal is still at the PCS_NOT_OK value after waiting the predetermined amount of time, and that the transition event has not occurred when the particular PCS status signal is back at the PCS_OK value after waiting the predetermined amount of time; wherein the electronic warning indication is outputted after the particular PCS status signal changes from the PCS_OK value to the PCS_NOT_OK value but before the link status signal transitions from the LINK_UP value to the LINK_DOWN value.