Communications plugs having capacitors that inject offending crosstalk after a plug-jack mating point and related connectors and methods
View Patent ↗Communications plugs are provided that include a plug housing. A plurality of plug contacts are mounted in a row at least partly within the plug housing. The plug contacts are arranged as differential pairs of plug contacts. Each of the differential pairs of plug contacts has a tip plug contact and a ring plug contact. A first capacitor is provided that is configured to inject crosstalk from a first of the tip plug contacts to a first of the ring plug contacts at a point in time that is after the point in time when a signal transmitted through the first of the tip plug contacts to a contact of a mating jack reaches the contact of the mating jack.
1. A communications plug, comprising:
a plug housing;
a plurality of plug contacts that are mounted in a row at least partly within the plug housing, the plurality of plug contacts arranged as a plurality of differential pairs of plug contacts so that each of the differential pairs of plug contacts has a tip plug contact and a ring plug contact; and
a first capacitor that is configured to inject crosstalk from a first of the tip plug contacts to a first of the ring plug contacts at a point in time that is after the point in time when a signal transmitted through the first of the tip plug contacts to a contact of a mating jack reaches the contact of the mating jack.
2. The communications plug of claim 1 , wherein the first capacitor is separate from the first of the tip plug contacts and the first of the ring plug contacts, and wherein a first electrode of the first capacitor is coupled to a non-signal current carrying portion of the first of the tip plug contacts and a second electrode of the first capacitor is coupled to a non-signal current carrying portion of the first of the ring plug contacts.
3. The communications plug of claim 2 , wherein the first of the tip plug contacts and the first of the ring plug contacts are mounted directly adjacent to each other in the housing and are part of different of the plurality of differential pairs of plug contacts.
4. The communications plug of claim 2 , wherein the plurality of plug contacts are mounted on a printed circuit board, and wherein the first capacitor is implemented within the printed circuit board.
5. The communications plug of claim 1 , wherein each of the plug contacts comprises a skeletal plug blade.
6. The communications plug of claim 5 , wherein the plug further comprises a printed circuit board, wherein the plurality of plug contacts comprises eight plug contacts that are arranged as four differential pairs of plug contacts, wherein each plug contact includes respective first and second ends that are mounted in the printed circuit board with the first end of each plug contact being closer to a front edge of the printed circuit board than is the second end of each plug contact.
7. The communications plug of claim 6 , wherein each of the plug contacts has a respective signal current carrying path that extends from the second end of each plug contact to a plug-jack mating point of the plug contact.
8. The communications plug of claim 6 , wherein each of the plug contacts has a respective signal current carrying path that extends from the first end of each plug contact to a plug-jack mating point of the plug contact.
9. The communications plug of claim 6 , wherein a first of the plug contacts of each differential pair of plug contacts has a respective signal current carrying path that extends from the second end of each plug contact to a plug-jack mating point of the plug contact, and wherein a second of the plug contacts of each differential pair of plug contacts has a respective signal current carrying path that extends from the first end of each plug contact to a plug-jack mating point of the plug contact.
10. The communications plug of claim 6 , wherein the plug contacts of a first of the differential pairs of plug contacts each have a respective signal current carrying path that extends from the second end of each plug contact to a plug-jack mating point of the plug contact, and wherein the plug contacts of a second of the differential pairs of plug contacts each have a respective signal current carrying path that extends from the first end of each plug contact to a plug-jack mating point of the plug contact.
11. The communications plug of claim 5 , wherein each skeletal plug blade includes a projection, and wherein the projections on adjacent plug blades extend in different directions.
12. The communications plug of claim 1 , wherein the first capacitor generates at least 75% of the capacitive crosstalk between the first of the tip plug contacts and the first of the ring plug contacts.
13. The communications plug of claim 1 , in combination with a communications cable that has a plurality of conductors, wherein the communications plug is attached to an end of the communications cable to provide a patch cord, and wherein each of the plurality of plug contacts is electrically connected to a respective one of the conductors of the communications cable.
14. The communications plug of claim 1 , wherein a first electrode of the first capacitor comprises a first plate-like extension that is part of a non-signal current carrying portion of the first of the tip plug contacts and a second electrode of the first capacitor comprises a second plate-like extension that is part of a non-signal current carrying portion of the first of the ring plug contacts.
15. The communications plug of claim 1 , wherein a first electrode of the first capacitor is coupled to a non-signal current carrying portion of the first of the tip plug contacts and a second electrode of the first capacitor is coupled to a signal current carrying portion of the first of the ring plug contacts.
16. The communications plug of claim 1 , wherein the first capacitor is connected to the non-signal current carrying portion of the first of the tip plug contacts by a conductive element that is not part of the first of the plug contacts.
17. A communications plug, comprising
a plug housing;
a plurality of plug contacts that are mounted in a row at least partly within the plug housing that are arranged as a plurality of differential pairs of plug contacts so that each of the differential pairs of plug contacts has a tip plug contact and a ring plug contact; and
a first capacitor that has a first electrode that is connected to a plug-jack mating point of a first of the tip plug contacts by a first substantially non-signal current carrying conductive path and a second electrode that is connected to a plug-jack mating point of a first of the ring plug contacts by a second substantially non-signal current carrying conductive path, wherein the first tip plug contact and the first ring plug contact are part of different ones of the plurality of differential pairs of plug contacts.
18. The communications plug of claim 17 , wherein the first tip plug contact and the first ring plug contact are mounted next to each other in the row.
19. The communications plug of claim 18 , wherein the first capacitor comprises a capacitor that is formed within a printed circuit board.
20. The communications plug of claim 19 , wherein the first tip plug contact comprises a skeletal plug contact having a first end mounted in the printed circuit board that is directly connected to a first wire connection terminal that is mounted in the printed circuit board by a first conductive path through the printed circuit board, a central portion, at least part of which is configured to engage a contact of a mating jack, and a second end that is opposite the first end, and wherein the second end of the first tip plug contact is directly connected to the first electrode of the first discrete capacitor by the first substantially non-signal current carrying conductive path.
21. A method of reducing the crosstalk generated in a communications connector that comprises a plug having eight plug contacts that are mated at a plug-jack mating point with respective ones of eight jack contacts of a mating jack, each of the eight mated sets of plug and jack contacts being part of a respective one of eight conductive paths through the connector that are arranged as first through fourth differential pairs of conductive paths, the method comprising:
providing a plug capacitor between one of the conductive paths of the first differential pair of conductive paths and one of the conductive paths of the second differential pair of conductive paths, wherein the plug capacitor is configured to inject crosstalk between the first and second differential pairs of conductive paths at a point in time that is after the point in time when a signal transmitted over the first differential pair of conductive paths in either the direction from the plug to the jack, or the direction from the jack to the plug, reaches the plug-jack mating point;
providing a jack capacitor between one of the conductive paths of the first differential pair of conductive paths and one of the conductive paths of the second differential pair of conductive paths, wherein the jack capacitor will inject crosstalk between the first and second differential pairs of conductive paths at a point in time that is after the plug-jack mating point when a signal is transmitted over the first differential pair of conductive paths in either the direction from the plug to the jack or the direction from the jack to the plug.
22. The method of claim 21 , wherein the plug capacitor and the jack capacitor inject the crosstalk at substantially the same point in time when a signal is transmitted in the direction from the plug to the jack.
23. The method of claim 21 , wherein the plug capacitor injects crosstalk having a first polarity and the jack capacitor injects crosstalk having a second polarity that is opposite the first polarity.
24. The method of claim 21 , wherein the plug capacitor comprises a discrete capacitor that is separate from the plug contacts that couples energy between the conductive paths associated with a first of the plug contacts and a second of the plug contacts that are next to each other.
25. The method of claim 24 , wherein an electrode of the plug capacitor is directly connected to a non-signal current carrying portion of the first of the plug contacts.
26. A patch cord, comprising:
a communications cable comprising first through eighth insulated conductors that are contained within a cable jacket and that are configured as first through fourth differential pairs of insulated conductors; and
an RJ-45 communications plug attached to a first end of the communications cable, wherein the RJ-45 communications plug comprises;
a plug housing;
first through eighth plug contacts that are mounted in a jack contact region that is at least partially within the plug housing, the first through eighth plug contacts electrically connected to respective ones of the first through eighth insulated conductors of the communications cable to provide four differential pairs of plug contacts; and
a printed circuit board mounted at least partially within the plug housing, the printed circuit board including a first capacitor that injects crosstalk between a first and a second of the differential pairs of plug contacts that has the same polarity as the crosstalk injected between the first and the second differential pairs of plug contacts in the jack contact region.
27. The patch cord of claim 26 , wherein the first capacitor comprises an inter-digitated finger capacitor that is implemented on the printed circuit board.
28. The patch cord of claim 26 , wherein at least some of the first through eighth plug contacts comprise skeletal plug blades.
29. The patch cord of claim 26 , wherein at least some of the first through eighth plug contacts comprise contact pads on the printed circuit board.
30. The patch cord of claim 26 , wherein the first capacitor comprises a plate capacitor that is implemented on the printed circuit board.
31. The patch cord of claim 26 , further comprising a mutual inductor that is formed between conductive traces on the printed circuit board, the mutual inductor configured to inject crosstalk between the first and second of the differential pairs of plug contacts that has the same polarity as the crosstalk injected between the first and second of the differential pairs of plug contacts in the jack contact region.