WO1997019499A1

WO1997019499A1 - Modular jack having reduced cross-talk enhancement

Info

Publication number: WO1997019499A1
Application number: PCT/IB1996/001228
Authority: WO
Inventors: Johannes Lambertus Van De Sandt; Lucas Soes; Jan Hendrik Ate Wiekamp
Original assignee: Whitaker LLC
Current assignee: Whitaker LLC
Priority date: 1995-11-17
Filing date: 1996-11-14
Publication date: 1997-05-29
Anticipated expiration: 1998-05-17
Also published as: GB9523588D0

Abstract

A data connector receptacle (10) for connecting signal transmission lines to contacts of a mating plug comprising a housing (12) having a plug receiving cavity (14) in communication with a plug receiving opening (16) for receiving the mating plug into the plug receiving cavity (14) and a plurality of contacts (1-8) each having a plug engaging end (1a-8a) extending into the plug receiving cavity (14) to electrically engage the contacts of the mating plug, a mating end (1b-8b) for electrically engaging the transmission line, and an intermediate section (1c-8c) are generally aligned, the data connector receptacle (10) being characterized in that a plurality of intermediate sections (1c, 2c, 4c, 5c, 7c, 8c) define a plane and at least two of the contacts (3, 6) include intermediate sections (3c, 6c) displaced from said plane and, if desired, a capacitance module (22) may be provided for capacitance equalization between the contacts (1-8) for enhancing performance of the receptacle (10).

Description

MODUIAR JACK HAVING REDUCED CROSS-TALK ENHANCEMENT

This invention relates to data transmission connectors and in particular to features incorporable therein to reduce cross-talk between adjacent signal lines.

As the speed (frequency) of data signals is becoming higher and higher, it is necessary to upgrade the performance of existing data connectors. In particular the modular jack receptacle has found wide spread current use and in order to fulfill the market requirements of the near future it is necessary to upgrade the performance of there products without effecting the arrangement or assignment of the contact interface. As the modular jack configurations have generally standardized mating interfaces, the coupling distance in the jack is more or less fixed.

Cross-talk or coupling between adjacent signal contacts is dependant upon the signal frequency, the coupling area and the distance between the contacts. For the standard 8-position modular jack, cross-talk is the highest between the contacts of contact pair 3-6 and the adjacent pairs. This is because of the relatively large distance between the contacts 3 and 6 which results in these contacts tending to act as individual contacts rather than a contact pair, which ultimately increases the effects of the cross-talk coupling. In order to overcome this problem, it is known to use cross-over contacts wherein adjacent contacts may be orientated to overlie one another and thereby bring the contacts closer together so that they continue to act as contact pairs. A problem with these cross-over contacts is that the contacts are ultimately difficult to produce as this structure involves complicated stamping and forming processes which ultimately add cost to the price of the modular jack. As one of the advantages of the modular jack receptacle is its wide spread use and therefore low cost, any design change that dramatically effects the cost will be resisted.

Therefore, a problem exists of providing a simple and economical modular jack that is fully compatible with existing standardized configurations while meeting the new requirements of high speed data signal transmission. The new requirement is referred to as Category 5. It is a further problem to be able to accomplish the aforegoing in a simple and economical manner. It is yet another problem to be able to provide the aforegoing while allowing for the enhancement of signal transmission characteristics beyond those that are presently being realized (i.e. from Category 5 to Category 6) .

These and other objects are accomplished by providing a data connector receptacle for connecting signal transmission lines to contacts of a mating plug comprising a housing having a plug receiving cavity in communication with a plug receiving opening for insertion of the mating plug into the plug receiving cavity and a plurality of contacts each having a plug engaging end extending into the plug receiving cavity to electrically engage the contacts of the mating plug, a mating end for electrically engaging the transmission line, and an intermediate section therebetween, where the intermediate sections of the plurality of contacts are generally aligned, the data receptacle being characterized in that a plurality of intermediate sections define a plane and at least two of the contacts include intermediate sections displaced from said plane.

It is an advantage of this invention that high speed data transmission may be accomplished without adverse cross-talk between adjacent contacts. It is another advantage of this invention that the standardized mating interface maybe realized. It is yet another advantage of this invention that a simple and cost-effective design iε provided. It is still another advantage of this invention that a modular jack receptacle can be providing that meets Category 5 requirements and that jack can be upgraded by the addition of a capacitance module to Category 6 without other changes, thereby enabling a given base design to be utilized in both products. It is yet still another advantage of this invention, that the performance of the modular jack may be enhanced further by the inclusion of a capacitance module coupled to at least two of the contacts, whereby the speed of data signal transmission may be yet further increased. It is still yet another advantage of this invention, that the capacitance module provides additional capacitance to the product without direct capacitance coupling to the contacts. It is another advantage that all of the above may be provided in conjunction with a standard plug.

The invention will now be described by reference to the included drawings, wherein: Figure 1 is an upper perspective view of a modular jack according to the present invention;

Figure 2 is an upper perspective partially exploded view of the modular jack of Figure l;

Figure 3 is an upper side perspective view of the contacts incorporated into the connector of Figure 1;

Figure 4 is a schematic view of the capacitance coupling of the contacts of Figure 3;

Figure 5 is a schematic view of the capacitance coupling necessary to improve upon the contact arrangement of Figure 3;

Figure 6 is an upper perspective view of the contacts arranged as shown in Figure 3 and further including an additional capacitance module affixed thereto providing the enhanced capacitance as illustrated in Figure 5; Figure 7 is an upper perspective view of the capacitance module shown in Figure 6; and

Figure 8 is a lower perspective view of the capacitance module shown in Figure 6.

With reference now to Figure 1, a data connector receptacle configured as a modular jack receptacle according to the present invention is shown generally at

10. The modular jack receptacle 10 includes a housing 12 having a plug receiving cavity 14 that is in communication with a plug receiving opening 16 for receiving a mating modular plug (not shown) . The mating plug, plug receiving cavity 14 and plug receiving opening 16 are all specified in common standards and will not be described in detail herein. The housing 12 includes an open upper portion 18 wherein a contact carrier body 20 is received. The contact carrier body 20 includes a plurality of contacts 1-8 extending therefrom. In addition, a capacitance module 22 may be further carried by the contact carrier 20. Extending from the opposite side of the housing 12 from which the plug receiving opening 16 is formed are board mount anchors 24 for affixing the modular jack 10 to a printed circuit board. It is important to note that while the example presented herein is for PCB applications, the invention is not so limited.

With reference now to Figure 2, the contact carrier 20 includes an overmoulded carrier body 26 wherein the contacts 1-8 are encased. The carrier body 26 includes a pair of rails 28 that are slidably received within tracks 30 of the housing 12. A comb portion 32 is provided for properly orienting the contacts 1-8 for engagement with contacts of the mating plug. The carrier body 26 further includes an upper seat 34 wherein the optional capacitance module 22 may be received. The seat 34 comprises a base 36 and three interconnected walls 38,40,42 that form a U- shaped partition wherein the capacitance module 22 is received. The capacitance module 22 includes a capacitance plate 44 formed of upper conductive plates 46a-c separated from lower conductive plates 48a,b (best seen in Figure 8) that are disposed on the opposite side of an insulating plate 50. A plurality of contacts 51,53,54,56,58 are provided for interconnecting with the respective contacts 1,3,4,6,8. Other capacitance structures may be incorporated into the plate 44. With reference now to Figure 3, the contacts 1-8 of the modular jack receptacle 10 are shown. Each of the contacts 1-8 include a respective mating end la-8a that are aligned in a row of reversely bent cantilever resilient arms, as is common for a connector of thiε type. The contacts 1-8 further include a mating end lb-8b. In the embodiment shown, the mating end lb-8b are arranged and configured for mounting upon a printed circuit board. It is important to note that other mating end configurations may be accommodated. Between corresponding plug engaging ends la-8a and mating ends lb-8b are intermediate sections lc-8c. The standard configuration for an 8-position modular jack utilizes contacts 1 and 2 as a signal pair, contacts 3 and 6 as another signal pair, contacts 4 and 5 as yet another signal pair and contacts 7 and 8 as still yet another signal pair. As can be seen in Figure 3, the contacts of three of the signal pairs are adjacent each other while the contacts 3,6 of the remaining signal pair are spaced to individually fall between the other signal pairs. A problem exists that in this configuration, the contacts 3,6 behave as essentially individual contacts as opposed to a pair. The result of this is that the adverse effects of the capacitive coupling such as cross-talk are most evident with respect to these contacts.

In order to reduce these adverse effects, it is desirable to separate the intermediate sections 3c,6c of the second pair as far as possible from their adjacent pairs. As can be seen in Figure 3, the plug engaging end la-8a of contacts 1,2,4,5,7,8 are interconnected to their intermediate sections by way of a relatively sharp bend ld,2d,4d,5d,7d,8d that are all essentially identical. The intermediate sections lc,2c,4c,5c,7c,8c are all basically aligned and define a plane. The contacts 3,6 of the second pair have their plug engaging end 3a,6a interconnected to their intermediate sections 3c,6c by a leg portion 3e,6e, the leg portion 3e,6e raises the intermediate section 3c,6c outside of the plane defined by the intermediate sections of the other pairs. This maximizes the separation. This separation of intermediate sections provides increased ability to transmit signals at high frequency without the adverse effect of cross-talk. All of the intermediate sections lc-8c are generally parallel to each other without any complicated cross-over or overlap therebetween.

With reference now to Figure 4, a schematic view of the capacitance coupling is shown. The contacts 1-8 are shown having their basic polarization indicated where contacts 1,3,4,7 can be thought of as being positively polarized and contacts 2,5,6,8 as being negatively polarized to correspond to respective differential pair signal transmission lines (not shown) . As can be seen, contact 3 is capacitively coupled to contacts 1 and 2 by way of capacitance c, and c₂. In order to eliminate cross¬ talk therebetween, it is necessary that C] equal c₂. This is further the case with respect to the capacitance coupling of contact 3 to the contacts 4 and 5. This is also the case with respect to the coupling of contact 6 to contacts 4,5 and 7,8 as is apparent from Figure 4. While the physical separation apparent therein is sufficient to reduce the capacitance coupling therebetween for meeting Category 5 requirements to satisfy near future applications, it may be desirable to further enhance the actual equalization of the relevant capacitance to meet next generation (Category 6) applications.

With reference now to Figure 5, with respect to contact 3 and pair 1 comprising the contacts 1 and 2 it is necessary to effect the size of the capacitance of c₂. This is accomplished by providing an additional capacitance C_A. By adjusting C_A it is possible that the situation of c, being greater than c₂ which produces cross-talk may be compensated such that c, will equal c₂ effective that includes C_A. As can be further seen in Figure 5, additional capacitances C_A,C_B,C_C,C_D would all need to be provided to equalize the respective capacitances.

With reference now to Figure 6, the contacts shown in Figure 3 are further enhanced by the addition of the capacitance module 22. The capacitance module 22, as described above, includes upper capacitance plates 46a-c that are affixed to an upper surface 60 of an insulative plate 50. As can be seen, contact 51 is connected to plate 46a, contact 54 is connected to plate 46b and contact 58 is connected to plate 46c. These contacts 51,54,58 are further connected to respective intermediate sections lc,4c,8c of contacts 1,4,8. In order to affix the contacts to the respective intermediate sections, either a mechanical engagement or a welding may be used.

With reference now to Figure 7 and Figure 8, the contacts 51,53,54,56,58 are interconnected to their respective plate portions 46a-c and 48a,b by soldering at a foot portion 51a,53a,54a,56a,58a. It is also further apparent that the plates 48a,48b capacitive couple with at least one of the upper plates 46a,46c. The size and configuration of each of the plates 46a-c and 48a,b are selected based on the capacitance needed to provide the desired capacitance alignment in order to produce the no- cross-talk condition described above. Figure 9 shows the process of creating a module 20 with an overmoulded housing encompassing a capacitance module. As plates 46a-c and 48a,b are provided on both sides of the plate 50, a self contained capacitance module 22 is provided. In this structure the plates 46a-c and 48a-b cooperate with each other, but do not cooperate with contacts 1-8 to provide the needed additional capacitance. It is important to note that with reference to Figure 1, the capacitance module 22 may be received within the housing 12 in such a manner that some of the plates 46a-c may be exposed so that is necessary, active adjustment of the capacitance may occur in order to further enhance the performance of the connector. This could be accomplished by simple trimming of the metallic plates. In addition, if desirable, since the capacitance module 22 is self contained, as described above, other orientations of the module 22 are possible including fitting the module between the place defined by contacts 1,2,4,5,7,8 and the contacts 3,6 are disposed therefrom, whereby the contacts 51,54,58 extending from one side of the module 22 and the contacts 53,56 extending from the other.

Claims

1. A data connector receptacle (10) for connecting signal transmission lines to contacts of a mating plug comprising a housing (12) having a plug receiving cavity (14) in communication with a plug receiving opening (16) for receiving the mating plug into the plug receiving cavity (14) and a plurality of contacts (1-8) each having a plug engaging end (la-8a) extending into the plug receiving cavity (14) to electrically engage the contacts of the mating plug, a mating end (lb-8b) for electrically engaging the transmission line, and an intermediate section (lc-8c) are generally aligned, the data connector receptacle (10) being characterized in that a plurality of intermediate sections (lc,2c,4c,5c,7c,8c) define a plane and at least two of the contacts (3,6) include intermediate sections (3c,6c) displaced from said plane.

2. The data connector receptacle of claim 1, further characterized in that a carrier body (20) retains the contacts (1-8) therein, said carrier body (20) being receivable in an opening (18) in the housing (12) .

3. The data connector receptacle of claim 1 or claim 2, further characterized in that the contacts (1-8) are cylindrical members.

4. The data connector receptacle of anyone of the preceding claims, further characterized in that the displaced intermediate contact sections (3c,6c) are separated by at least one intermediate contact section (4c,5c) within the plane.

5. The data connector receptacle of any one of the preceding claims characterized in that the receptacle is an 8 position modular jack having 8 contact where the contacts corresponding to positions 3 and 6 include the displaced intermediate sections. 6. The data connector receptacle of any one of the preceding claims, further characterized in that an additional capacitance module (22) is coupled to at least two displaced contacts (3,

6).

7. The data connector receptacle of claim 6, further characterized in that the additional capacitance module (22) is formed of conductive plates (46a-c;48a,b) on opposite sides (60,62) of insulative board (50) where at least some portion of the plates are exposed for trimming.

8. The data connector receptacle of claim 6 or claim 1 , further characterized in that two conductive plates (48a,b) are affixed to one side (62) of the board (50) and three (46a-c) are affixed to the other side (60) each plate (46a-c;48a,b) being connected to one of the contacts (1,3,4,6,8).

9. The data connector receptacle of any one of the preceding claims where the connector includes eight contacts that are to be connected to four pairs of conductive lines such that six of the contacts are formed into three sets of two adjacent contacts that are disposed in the plane to which three of the four pairs of conductive lines are to be attached and the two remaining contacts are to be connected to the remaining pair of conductive lines, the two remaining contacts being displaced out of the plane and separated by at least one of the three sets.