Abstract: A physical layer device configured to interface with a plurality of pairs of wires. The physical layer device includes a cable test module configured to transmit a pulse over the plurality of pairs of wires, measure a reflection of the pulse as received from the plurality of pairs of wires, and determine whether a short circuit exists in one of the plurality of pairs of wires based on the measure of the reflection of the pulse. An autonegotiation module is configured to perform autonegotiation to establish a link at a particular speed over the plurality of pairs of wires. The particular speed at which the link is established over the plurality of pairs of wires is based, at least in part, on whether a short circuit exists in one of the plurality of pairs of wires as determined by the cable test module.

Abstract: A network device including a physical layer (PHY) device and an autonegotiation module. The PHY device is configured to interface with N cable pairs, where N is greater than 1. The PHY device includes a cable test module configured to diagnose a short circuit in one of the N cable pairs. The autonegotiation module is configured to i) selectively perform autonegotiation to establish a link with a link partner at one of a first link speed and a second link speed that is lower than the first link speed, and ii) select between the first link speed and the second link speed in response to the cable test module diagnosing the short circuit.

Abstract: A network interface includes a physical layer (PHY) device that provides an interface to a cable. The PHY device includes an autonegotiation module that selectively performs autonegotiation to establish a link with a link partner based on link parameters and a cable test module that performs a cable test before the autonegotiation begins, that determines a cable performance parameter during the cable test, and that compares the cable performance parameter to a predetermined threshold. The autonegotiation module selects at least one of the link parameters based on the comparison.

Abstract: A physical layer device includes a cable test module that transmits a test pulse on a cable, measures a reflection amplitude, calculates a cable length, and determines a cable status based on the measured amplitude and the calculated cable length. A frequency synthesizer selectively outputs a plurality of signals at a plurality of frequencies on one end of the cable. An insertion loss calculator receives the signals from an opposite end of the cable and estimates insertion loss based on the received signals.

Abstract: A physical layer device includes a cable tester that determines a cable status of a cable and that includes a test module. The test module transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. An insertion loss estimator communicates with the cable tester, and estimates insertion loss of the cable based at least in part on a feedback equalizer gain.

Abstract: A cable tester that tests cable and that determines a cable status includes a pretest module that senses activity on pairs of the cable and that selectively enables testing based on the sensed activity. A test module is enabled by the pretest module, transmits a test pulse on one of the pairs, measures a reflection amplitude and calculates a cable length. The cable status includes an open status, a short status, and a normal status. The test module determines the cable status based on the measured amplitude and the calculated cable length. The test module measures received signals on at least one other pair after transmitting the test pulse on the one of the pairs, compares the received signals on the at least one other pair to a predetermined threshold, and determines a pair short status between the one of the pairs and the at least one other pair if the received signals exceed the predetermined threshold.

Abstract: A physical layer device comprises a first port adapted to communicate with one end of a cable. A second port is adapted to communicate with an opposite end of a cable. A cable tester communicates with the first and second ports and selectively tests the cable to determine a cable status, which includes an open status, a short status, and a normal status. The cable tester includes a test module that transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A frequency synthesizer selectively outputs a plurality of signals at a plurality of frequencies on the first port. An insertion loss calculator that receives the signals on the second port and that estimates insertion loss.

Abstract: A physical layer device comprises a first transceiver that selectively communicates with a cable medium. A detector detects a power over Ethernet (POE) device. A switching device selectively provides power from a power supply over the cable medium when the detector detects the POE device. A cable tester communicates with the first transceiver, tests the cable medium and determines a cable status, and delays testing of the cable medium when the detector detects the POE device until the switching device provides the power.

Abstract: A cable tester tests cable to determine a cable status. A mode selector selects one of a first operating mode and a second operating mode. A pretest module senses activity on the cable and selectively enables testing based on the sensed activity when in the first operating mode and enables testing when in the second operating mode. A test module is enabled by the pretest module, transmits a test pulse on the cable, measures a reflection amplitude and calculates a cable length. The cable status includes an open status, a normal status and a short status. The test module determines the cable status based on the measured amplitude and the calculated cable length.

Abstract: A cable tester comprises a test initiating module that performs B cable tests. Each of said B cable tests includes selectively transmitting a test pulse on the cable, measuring a reflection amplitude, and calculating a cable length. A test results module determines a cable status for each of said B cable tests based on said measured amplitude and said calculated cable length and that determines an overall cable status of the cable based on the cable at least one of passing and failing A out of B cable tests. A and B are integers greater than zero and B is greater than A.

Abstract: A physical layer device communicates over a cable and includes a cable tester that determines a cable status, which includes an open status, a short status and a normal status. The cable tester includes a pretest module that senses activity on the cable and selectively enables testing based on the sensed activity. A test module is enabled by the pretest module, transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A digital signal processor (DSP) communicates with the cable and that has a digital gain parameter. A cable length estimator communicates with the DSP and estimates cable length based on the digital gain parameter.

Abstract: A physical layer device including a first port and a second port comprises a cable tester that communicates with the first and second ports and that determines a cable status, which includes an open status, a short status, and a normal status. Opposite ends of a cable selectively communicate with the first and second ports. The cable tester includes a test module that transmits a test pulse on the cable, measures reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A frequency synthesizer communicates with the cable and that selectively outputs a plurality of signals at a plurality of frequencies on the first port. An insertion loss calculator receives the signals on the second port and that estimates insertion loss.

Abstract: A cable tester includes a pretest module that senses activity on a cable and selectively enables testing depending upon the sensed activity. A test module is enabled by the pretest module, transmits test pulses on the cable, measures a refelction amplitude, calculates a cable length, and determines a cable status based on the measures amplitude and the calculated cable length. A polarity detector communicates with the cable tester and detects a polarity of at least one pair of the cable. The test module senses activity on a first pair of the cable, enables testing if activity is not detected for a first period, and enables testing of the first pair if, during the first period, activity is detected on the first pair and is subsequently not detected on the first pair for a second period after the activity is detected.

Abstract: A cable tester tests cable to determine a cable status. The cable status includes an open status, a normal status and a short status. A pretest module senses activity on the cable and selectively enables testing based on said sensed activity. A test module is enabled by the pretest module, transmits a test pulse on the cable, measures a reflection amplitude and calculates a cable length. The test module determines the cable status based on the measured amplitude and the calculated cable length.

Abstract: A network switch having switch ports for full-duplex communication of data packets with respective network nodes according to Ethernet (IEEE 802.3) protocol that flexibly assigns memory access slots to access an external memory according to programmable information. A scheduler within an external memory interface assigns the memory access slots to the respective network switch ports according to a programmed sequence written into an assignment table memory from an external programmable data storage device.

Abstract: A physical layer device includes a cable tester that determines a cable status. A test module transmits a test pulse on the cable, measures reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A first digital signal processor (DSP) communicates with a first pair of the cable and includes a first echo canceller having a finite impulse response (FIR) filter with taps and a first crosstalk canceller having a FIR filter with taps. A second DSP communicates with a second pair of the cable and includes a second echo canceller having a FIR filter with taps and a second crosstalk canceller having a FIR filter with taps. The cable tester calculates a distance to at least one of echo and crosstalk based on values of the taps of the first echo canceller and the second crosstalk canceller.

Abstract: A physical layer device communicates over a cable and includes a cable tester that determines a cable status. The cable tester includes a pretest module that senses activity on the cable. A test module transmits a test pulse on the cable, measures reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A first digital signal processor (DSP) communicates with a first pair of the cable and includes a first echo canceller and a first finite impulse response filter with first taps. A second DSP communicates with a second pair of the cable and includes a second echo canceller and a second finite impulse response filter with second taps. At least one of the physical layer device and the cable tester estimates skew between the first and second pairs based on values of the first and second taps.

Abstract: A physical layer device is provided that includes an autonegotiation circuit that negotiates a link with a link partner at first and second link speeds. The physical layer device also includes a cable tester that tests a cable and that determines a cable status of the cable before autonegotiation circuit negotiates the link at the first and second link speeds.

Abstract: A physical layer device communicates with a second physical layer device over a cable. The physical layer device includes a cable tester that identifies when the second physical layer device is disconnected from the cable. The cable tester includes a test initiating circuit that initiates a cable test when a link is lost, a test module that transmits test pulses on the pairs of the cable, measures reflection amplitudes, calculates cable lengths, and determines whether the pairs have said open status based on said measured amplitude and said calculated cable length, and a reporting circuit that generates a disconnect signal when at least one of the pairs has an open status.

Abstract: A physical layer device including a first port, a second port, and a cable that has one end that communicates with the first port and an opposite end that communicates with the second port. A cable tester tests the cable to determine a cable status, which includes an open status, a short status, and a normal status. A pretest module senses activity on the cable and selectively enables testing depending upon the sensed activity. A test module transmits a test pulse on the cable, measures a reflection amplitude, calculates a cable length, and determines the cable status based on the measured amplitude and the calculated cable length. A frequency synthesizer communicates with the cable and that selectively outputs a plurality of signals at a plurality of frequencies on the first port. An insertion loss calculator receives the signals on the second port and that estimates insertion loss.