Electrical connectors – With insulation other than conductor sheath – Plural-contact coupling part
Utility Patent
1999-06-04
2001-01-02
Bradley, Paula (Department: 2833)
Electrical connectors
With insulation other than conductor sheath
Plural-contact coupling part
C439S620040
Utility Patent
active
06168474
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to the compensation of crosstalk in communication system connectors. More particularly, the invention relates to compensation of crosstalk occurring in patch distribution modules.
BACKGROUND OF THE INVENTION
Telecommunications and data transmission systems more and more often are being called upon to operate at higher and higher frequencies with the huge increases in signaling traffic. Although present day cables and wiring theoretically can handle such increased frequencies, one of the problems encountered is an increase in crosstalk as frequency of transmission is increased. For example, at frequencies above one megahertz (1 MHz), the degradation of signals due to crosstalk can become unacceptable. The source of such crosstalk is the electromagnetic radiation from the conductor pairs in, for example, a transmission cable which induces unwanted signals in adjacent pairs. This crosstalk materially decreases signal-to-noise ratios and results in increased error rates in data transmission. Various arrangements have been used for reducing crosstalk in cables, such as shielding individual pairs, helically winding twisted pairs, or increasing the physical separation of one pair from another.
Crosstalk also occurs in the hardware used to connect the cable or cables. The design of hardware, and more particularly the connectors therefor, normally must include provisions for reducing crosstalk within the connectors themselves or for counteracting the crosstalk produced by such connectors. The plugs that commonly are used in telecommunications equipment generally include four pair connectors. In some instances, it is desirable to connect such plugs to 25 pair connectors. The conductors within both the plugs and 25 pair connectors necessarily are oriented both parallel and close together, a condition that leads to excessive crosstalk at high frequencies.
In an effort to satisfy the ANSI/EIA/TIA standards, many connectors have been designed with internal crosstalk compensation. In several of these connectors, it has been found that the crosstalk coupling induced by connector interface can be reduced to a great extent by routing the conductors of the connectors to a printed wiring board to produce a net reduction in undesired crosstalk. The circuit traces that form the pairs of conductors preferably are arranged in a pattern that produces crosstalk opposite in polarity to the pattern that produces the crosstalk. One such arrangement is disclosed in U.S. Pat. No. 5,700,167, issued to Pharney, et al. In this patent, a patch distribution module is disclosed that incorporates a plurality of connector jacks that each includes means for inducing crosstalk compensation. These connector jacks are mounted to an internal circuit board comprising a plurality of individual layers that provide an additional measure of crosstalk compensation to provide a net amount of compensation. Although providing for connection between modular plugs and individual wire conductors with acceptable signal-to-noise ratios, utilization of the patch distribution module disclosed in this patent is limited to the coupling of four pair plugs with such individual conductors. Therefore, this module cannot be used to couple such plugs to higher order connectors such as 25 pair connectors.
Although there are several connectors available that are capable of coupling standard modular plugs to 25 pair connectors, applicants know of no such connector which satisfies the stringent requirements of ANSI/EIA/TIA. In Category 5 of ANSI/EIA/TIA, it is required that a connector exhibit a pair-to-pair, nearend crosstalk (“NEXT”) loss which does not exceed 40 dB at 100 MHz. Since 25 pair connectors are designed to carry six times the signals of ordinary four pair cable, this requirement must be met on an even more stringent power sum basis since, for each pair, crosstalk couplings from each of the other pairs must be compensated. The requirements for satisfying the crosstalk on a power sum basis are set forth in Category 5E of ANSI/EIA/TIA.
From the above, it can be appreciated that it would be advantageous to have an electrical connector, such as a patch distribution module, capable of electrically connecting modular plugs to 25 pair connectors, which complies with Category 5E of ANSI/EIA/TIA.
SUMMARY OF THE INVETION
The present invention relates to a communications connector having internal crosstalk compensation. The connector comprises an internal circuit board having a plurality of circuit board layers that include a plurality of capacitive and inductive devices that counteract the crosstalk created by a first other connector mated to the communications connector. The circuit board therefore comprises a first crosstalk compensation region. In addition, the communications connector comprises an internal fanout assembly mounted to the internal circuit board. The fanout assembly has a plurality of conductors arranged so as to form a compensation area that counteracts crosstalk created by a second other connector mated to the communications connector. The fanout assembly therefore comprises a second crosstalk compensation region.
In a most preferred arrangement, the communications connector comprises a patch distribution module for electrically coupling at least one modular plug to a multiple pair connector such as a 25 pair connector. In this arrangement, the connector further includes an outer housing composed of a dielectric material and at least one connector jack adapted to electrically connect to the at least one modular plug, an internal fanout assembly having a plurality of conductors arranged so as to form a compensation area that counteracts crosstalk created by the multiple pair connector.
The circuit board can comprise a crosstalk compensating circuit board having a plurality of circuit board layers including a component side and a wiring side, a plurality of capacitive devices provided on the circuit board layers, and at least one capacitive device provided on the outer surface of at least one of the component and wiring sides, the at least one capacitive device being arranged so as to produce a predetermined capacitance in conjunction with at least one of the plurality of capacitive devices provided on the circuit board layers, the at least one capacitive device further being manually reducible in size so as to adjust the amount of capacitance created therewith such that the amount of crosstalk compensation provided by the crosstalk compensation circuit board can be adjusted.
The objects, features, and advantages of this invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings. It is intended that all such additional features and advantages be included therein with the scope of the present invention, as defined by the claims.
REFERENCES:
patent: 5562479 (1996-10-01), Pallas et al.
patent: 5639261 (1997-06-01), Rutkowski et al.
patent: 5700167 (1997-12-01), Pharney et al.
German Michael Gregory
Hess Jeffrey Allen
Pharney Julian Robert
Spitz William Tracy
Steele Ted E.
Bradley Paula
Lucent Technologies - Inc.
Nguyen Phuongchi
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