Diagnosing cable faults within a network

A method of detecting a cable fault, comprising:

• transmitting a first pulse signal from a node to a cable of a shared bus;
• observing a first signal received at the node in response to the transmitted first pulse signal;
• determining a state of the observed first signal at each sampling time of a plurality of sampling times of the observed first signal at least partially based on a comparison of the observed first signal at each sampling time of the plurality of sampling times to a first threshold value being positive and between double an amplitude of the first pulse signal and the amplitude of the first pulse signal;
• transmitting a second pulse signal from the node to the cable of the shared bus;
• observing a second signal received at the node in response to the transmitted second pulse signal;
• determining a state of the observed second signal at each sampling time of a plurality of sampling times of the observed second signal at least partially based on a comparison of the observed second signal at each sampling time of the plurality of sampling times of the observed second signal to at a second threshold value having a positive value and an amplitude between an amplitude of the second pulse signal and zero;
• transmitting a third pulse signal from the node to the cable of the shared bus;
• observing a third signal received at the node in response to the transmitted third pulse signal;
• determining a state of the observed third signal at each sampling time of a plurality of sampling times of the observed third signal at least partially based on a comparison of the observed third signal at each sampling time of the plurality of sampling times of the observed third signal to a third threshold value being between zero and a negative amplitude of the third pulse signal;
• and
• determining a fault condition at least partially based on the state of the observed first signal at each sampling time of the plurality of sampling times of the observed first signal, the state of the observed second signal at each sampling time of the plurality of sampling times of the observed second signal, and the state of the observed third signal at each sampling time of the plurality of sampling times of the observed third signal.

A method of detecting a fault in a cable of a network, the method comprising:

• transmitting a plurality of pulse signals from a node to a cable of a shared bus of the network;
• observing a number of signals received at the node in response to the plurality of pulse signals;
• determining a plurality of values for each of the number of observed signals at least partially based on a comparison of an amplitude of each sample of a plurality of samples of each of the number of observed signals to each of a first threshold value, a second threshold value, and a third threshold value, the first threshold value greater than an amplitude of a pulse signal of the plurality of pulse signals, the second threshold value having a positive value and an amplitude between the amplitude of the pulse signal and zero;
• and
• determining a fault condition of the cable at least partially based on the number of observed signals.

A single-pair Ethernet physical layer (PHY), comprising:

• a transmitter configured to transmit a plurality of pulse signals to a cable of a shared bus;
• a receiver configured to observe a number of second signals received in response to the plurality of transmitted pulse signals;
• and
• a signal detector configured to:
• compare an amplitude of each sample of a plurality of samples of each of the number of second signals to at least three threshold values, the at least three threshold values including:
• a first positive threshold value greater than an amplitude of each of the plurality of pulse signals;
• and a second, lower positive threshold value between the amplitude of each of the plurality of pulse signals and zero volts;
• and
• generate a detector output signal for each sample of the plurality of samples of each of the number of second signals at least partially based on the comparison of the amplitude of each sample of the plurality of samples of each of the number of second signals to the at least three threshold values;
• and
• fault detection logic coupled to the signal detector and configured to:
• receive the detector output signal for each sample of the plurality of samples of each of the number of second signals;
• and
• determine a fault condition of the cable at least partially based on the plurality of transmitted pulse signals and on the detector output signals.