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.
1. A physical layer device configured to interface with a plurality of pairs of wires, the physical layer device comprising:
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 received from the plurality of pairs of wires; and
an autonegotiation module configured to perform autonegotiation to establish a link at a particular speed over the plurality of pairs of wires, wherein 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.
2. The physical layer device of claim 1 , wherein the cable test module is configured to:
compare the reflection of the pulse to a predetermined threshold; and
determine that a short exists in one of the plurality of pairs of wires in response to the reflection of the pulse being greater than the predetermined threshold.
3. The physical layer device of claim 2 , wherein the predetermined threshold is greater than an expected crosstalk level.
4. The physical layer device of claim 1 , wherein the plurality of pairs of wires comprises a CAT5 UTP cable.
5. A network device comprising the physical layer device of claim 1 .
6. A method for establishing a link over a plurality of pairs of wires, the method comprising:
transmitting a pulse over the plurality of pairs of wires;
transmit a pulse over the plurality of pairs of wires,
measuring a reflection of the pulse as received from the plurality of pairs of wires, and
determining whether a short circuit exists in one of the plurality of pairs of wires based on the measure of the reflection of the pulse received from the plurality of pairs of wires; and
performing autonegotiation to establish the link, at a particular speed, over the plurality of pairs of wires, wherein the particular speed at which the link is established over the plurality of pairs of wires is based, at least in part on, the determination of whether a short circuit exists in one of the plurality of pairs of wires.
7. The method of claim 6 , wherein determining whether a short circuit exists in one of the plurality of pairs of wires comprises:
comparing the reflection of the pulse to a predetermined threshold; and
determining that a short exists in one of the plurality of pairs of wires in response to the reflection of the pulse being greater than the predetermined threshold.
8. The method of claim 7 , wherein the predetermined threshold is greater than an expected crosstalk level.
9. The method of claim 6 , wherein the plurality of pairs of wires comprises a CAT5 UTP cable.