1. Field of the Invention
This invention relates to an improved jack for data transmission, and in the preferred embodiment provides a jack having improved cross-talk characteristics.
2. The Prior Art
Jacks (and their associated plugs) are widely used in data transmission systems for providing a plug-in connection between components. For example, jacks are extensively used on patch panels and wall outlets of structured cabling systems and on electronic equipment to permit connection of equipment to structured cabling systems using patch leads. The so called RJ45 plug is extensively used within the cabling industry and the vast majority of jacks are devised to be compatible with RJ45 plugs.
There are various internationally agreed standards for the performance of structured cabling systems. The current mainstream standards are the so called “Category 5” (commonly referred to as Cat 5) and the somewhat improved “Category 5 enhanced” (generally referred to as Cat 5e). A higher standard (Category 6 or Cat 6) has recently been proposed. Cat 6 specifications require lower levels of near end cross-talk (NEXT) and far end cross-talk (FEXT) and improved return loss values than the earlier Cat 5 and Cat 5e standards. In order to meet Cat 6standards it has been necessary to re-design both plugs and jacks, whilst keeping within the physical parameters of the RJ45 plug specification.
By careful design of the plug and the circuit board to which the jack is secured it has been possible to design plug and jack combinations which meet Cat 6 standards without any fundamental alteration to the standard jack construction. However, it is now considered desirable that both the plug and jack of Cat 6 specification equipment must be capable of meeting Cat 5 specification when used with a mating Cat 5 component. In other words, it is now desirable that when a Cat 6 plug is inserted into a Cat 5 jack, or a Cat 5 plug is inserted in a Cat 6 jack, the overall combination should meet Cat 5 standards.
We have now devised an improved jack which assists in meeting the desideratum of rearward compatibility to Cat 5 standards.
According to one aspect of the present invention a jack comprises a body having mounted thereon a multiplicity of metal strips, the metal strips including: a first group of metal strips each of which includes a contact portion for contacting a conductor of a mating plug and a connection portion for connection to a printed circuit board on which the jack, in use, is mounted; and a second group of metal strips each of which extends parallel to at least one metal strip of the first group over a part of the length of the metal strip of the first group and which is electrically connected to a different metal strip of the first group.
In the preferred embodiment of the invention the strips of the second group are cropped so that they do not include any portion in the region of the contact portions of the first group of metal strips.
Preferably, the metal strips include a common region which is encapsulated in a suitable plastics material. The contact portions of the first group extend from one end of the encapsulated region and the connection portions of the first group of strips extend from the other end of the encapsulated region. Preferably, the strips of the second group do not extend beyond the encapsulated region in the direction of the contact portions.
In the particularly preferred embodiment of the invention the contact strips are formed by two superimposed layers of a pre-formed common blank, one of the layers of blank being inverted relative to the other layer.
In the particularly preferred embodiment of the invention at least some of the strips include pad portions which co-operate with the pad portions of others of the strips to enhance impedance matching characteristics of the jack.
The above and further features and advantages of the invention will become clear from the following description of a preferred embodiment thereof given by way of example only, reference being had to the accompanying drawings wherein:
Referring firstly to
Each groups of strips 4 comprises five strips A,B,C,D, and E. It will be noted that, as manufactured, each strip is continuous between and is initially integral with the side regions 2,3. The strips A,C and E include pads 6 for impedance matching purposes, as described in more detail below.
The strips A,B,C and E will, in the finished jack, provide contact portions for electrical connection to corresponding contacts of a plug. The region 7 of the strips which will provide the contact portions may be suitably treated after the blanks have been formed, for example by mechanical treatment and/or electro-plating.
It will be noted that the strip D will not provide a contact portion in the finished jack.
In order to form a jack, two layers of the blank material are required, the second layer being superimposed on the first layer but inverted relative to the first layer. The blank 1 shown in
To form the jack, the two layers of blank material are superimposed as shown in
In order to form a contact sub-assembly for insertion into a jack body a common central region 8 of the strips 4 is encapsulated in a suitable plastics encapsulation 9. As a practical matter, the encapsulation can conveniently be done in two stages by forming an initial encapsulation 9A which encapsulates the common region 8 of the lower blank and forming a second encapsulation 9B which encapsulates the common region 8 of the upper blank. The encapsulations 9A and 9B may be formed separately and fixed together after moulding. Alternatively, encapsulation 9A may be formed, the upper blank may be superimposed on that encapsulation, and the encapsulation 9B may be formed in situ. The resultant arrangement is shown on the left hand portion of FIG. 4 and the arrangement of the strips prior to encapsulation is shown on the right hand portion of FIG. 4. It will be appreciated that, in practice, there will be a number of intermediate stages between the left and right hand portions of FIG. 4. The totally unencapsulated and totally encapsulated stages are shown in juxtaposition for convenience only.
Once the encapsulation has been completed so that the configuration shown on the left hand portion of
It will be noted that, in the assembled configuration of the strips, the pad 6 associated with strip UE overlies and is substantially coterminous with the pad 6 of the strip LA. Similarly, the pad of the strip UC overlies and is substantially coterminous with the pad 6 of the strip LC. Finally, the pad 6 of the strip UA overlies and is substantially coterminous with the pad 6 of the strip LE. The pairs of mating pads 6 do not materially affect the cross-talk of the jack but are useful in assisting impedance matching of the jack.
It will be appreciated that whilst in the preferred embodiment of the invention the contact portions of strips LD and UD are electrically connected to their respective overlying and underlying strips UB and LB other arrangements may be desirable depending on the exact nature of the cross-talk reduction which is required.
Whilst in the preferred embodiment of the invention two extra strips LD and UD are provided, it will be appreciated that the invention is not limited to the use of two additional strips but on the contrary encompasses any number of additional strips depending on the nature of the cross-talk compensation required.
Number | Date | Country | Kind |
---|---|---|---|
0022727 | Sep 2000 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCTGB01/03018 | 7/5/2001 | WO | 00 | 6/2/2003 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO0223681 | 3/21/2002 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
5362257 | Neal et al. | Nov 1994 | A |
5547405 | Pinney et al. | Aug 1996 | A |
5599209 | Belopolsky | Feb 1997 | A |
5938479 | Paulsen et al. | Aug 1999 | A |
6007368 | Lorenz et al. | Dec 1999 | A |
6179668 | Kan | Jan 2001 | B1 |
6283795 | Chen | Sep 2001 | B1 |
Number | Date | Country |
---|---|---|
0692884 | Jan 1996 | EP |
9963630 | Dec 1999 | WO |
Number | Date | Country | |
---|---|---|---|
20040033728 A1 | Feb 2004 | US |