Abstract:
A wire connecting unit for an electrical connector for communication and data transmission systems includes a circuit board with a free and a near end and having four pairs of contacts mounted in a cantilever manner. The wire connecting unit has specific contact configurations that reduce crosstalk, attenuation, propagation delay, and other electrical and magnetic properties that interfere with communication and data transmission. In one embodiment, a first row of contacts extends generally upwardly and backwardly from the free end of the printed circuit board toward the near end, and a second row of contacts placed further from the free end of the printed circuit board than the first row of contacts extends generally upwardly and backwardly from the free end toward the near end. Each adjacent contact can have only a single push foot that extends laterally and outwardly from its proximal end, remote from the other contact in the respective pair, allowing the contacts to be placed relatively close together to further reduce the electrical and magnetic properties that interfere with communication and data transmission.

Description:
REFERENCE TO RELATED APPLICATION 
     This application is related to U.S. patent application Ser. No. 09/250,186 of John J. Milner, Joseph E. Dupuis, Richard A. Fazio, and Robert A. Aekins, filed Feb. 16, 1999, and entitled “Wiring Unit with Angled Insulation Displacement Contacts”; the subject matter of which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a wire connecting unit for an electrical connector for communication and data transmission systems. The wire connecting unit has contact configurations that reduce crosstalk attenuation, propagation delay, and other electrical properties that interfere with communication and data transmission. More particularly, the present invention relates to a wire connecting unit for an electrical connector jack that terminates in eight conductors, with the eight conductors being configured to reduce electrical interference and interconnect with a plug. 
     BACKGROUND OF THE INVENTION 
     Due to significant advancements in telecommunications and data transmission speeds over unshielded twisted pair cables, the connectors (jacks, receptacles, patch panels, cross connects, etc.) have become critical factors in achieving high performance in data transmission systems, particularly at the higher frequencies. Some performance characteristics, particularly near end crosstalk, can degrade beyond acceptable levels at new, higher frequencies in the connectors unless adequate precautions are taken. 
     Often, wiring is pre-existing Standards define the interface geometry and pin separation for the connectors, making any changes to the wiring and to the connector interface geometry and pin separation for improving performance characteristics cost prohibitive. 
     The use of unshielded twisted pair wiring and the establishment of certain standards for connector interface geometry and pin separation were created prior to the need for high-speed data transmissions. Thus, while using the existing unshielded twisted pair wiring and complying with the existing standards, connectors must be developed that fulfill the performance requirements of today&#39;s higher speed communications, to maintain compatibility with the existing connectors. 
     Additionally, the wire connecting unit contacts are traditionally attached to a printed circuit board using solder attachments or compliant pins. Both assembly techniques have traditionally required a push foot mechanism on either side of the contact. These push foot mechanisms enable the contact to be inserted into the printed circuit board with the assembly fixturing. Since the contacts are on 0.040″ spacing and due to the annular (plated through) ring geometry requirements of a printed circuit board, contacts having a push foot on each side of each contact cannot be placed adjacent to each other in the same row. To space the contacts 0.040″ apart a single push foot would have to be utilized; however, a single push foot on one side of the contact creates a moment and can make it difficult to insert the contact into the printed circuit board. 
     Conventional connectors of this type are disclosed in U.S. Pat. No. 4,975,078 to Stroede, U.S. Pat. No. 5,186,647 to Denkmann et al, U.S. Pat. No. 5,228,872 to Liu, U.S. Pat. No. 5,376,018 to Davis et al, U.S. Pat. No. 5,580,270 to Pantland et al, U.S. Pat. No. 5,586,914 to Foster et al and U.S. Pat. No. 5,628,647 to Roharbaugh et al, the subject matter of each of which is hereby incorporated by reference. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a wire connecting unit for an electrical connector having a contact configuration that improves performance characteristics, but does not require changing standard connector interface geometry and contact separation. 
     Another object of the present invention is to provide a wire connecting unit for an electrical connector that is simple and inexpensive to manufacture and use. 
     A further object of the present invention is to provide a wire connecting unit for an electrical connector having contacts that connect to a printed circuit board and have only one push foot to allow adjacent contacts to be positioned in dose proximity in the same row. 
     The foregoing objects are basically obtained by a wire connecting unit for an electrical connector, comprising a circuit board having first and second areas, the first area having a free end and a near end. First, second, and third pairs of contacts are mounted in the first area adjacent the free end in a cantilever manner and extend upwardly and backwardly toward the near end. A fourth pair of contacts are mounted in the first area adjacent the near end in a cantilever manner and extend upwardly and forwardly toward the free end. 
     The foregoing objects are also obtained by a wire connecting unit for an electrical connector, comprising a circuit board having a wire termination portion and a plug connection portion. The plug connection portion has a first area and a second area, the first area having a proximal end and a distal end. A first plurality of contacts is mounted in the first area adjacent the distal end in a cantilever manner and extend generally upwardly and backwardly toward the wire termination portion. At least two of the contacts in the first plurality of contacts are adjacent to each other and have a single push foot extending therefrom A second plurality of contacts is mounted in the first area adjacent the proximal end and extend upwardly and backwardly toward the wire termination portion. 
     By forming the wire connecting unit for the electrical connector in as described, the connector will have improved performance characteristics, without changing the standard plug connector geometry and contact definitions. By placing the wire connecting unit&#39;s contacts in a particular configuration, maximum separation between critical contacts and positioning of other contacts adjacent each other to cancel out Gaussian fields is achieved, thereby improving electrical performance of the electrical connector. Additionally, by having only one push foot, the contacts can be placed relatively close together, increasing the contacts&#39; ability to cancel out the Gaussian field of the adjacent contact and thereby increasing electrical performance. 
     Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the invention. 
     As used herein, terms, such as “upwardly”, “downwardly”, “forwardly” and “backwordly”, are relative directions, do not limit the connecting unit to any specific orientation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
     FIG. 1 is a side elevational view in section of a wire connecting unit for an electrical connector according to the first embodiment of the present invention, prior to engagement with a plug. 
     FIG. 2 is a top view of the wire connecting unit for an electrical connector of FIG. 1 prior to engagement with a plug. 
     FIG. 3 is an end elevational view in section of the wire connecting unit taken along lines  3 — 3  of FIG.  1 . 
     FIG. 4 is an exploded top plan view of the wire connecting unit of FIG.  1 . 
     FIG. 5 is an enlarged, partial, end elevational view in section of an electrical contact for the wire connecting unit, shown in FIG. 3, having a push foot on two separate sides. 
     FIG. 6 is an enlarged, partial, end elevational view in section of an electrical contact for the wire connecting unit, shown in FIG. 3, having only one push foot. 
     FIG. 7 is a partial top perspective view of a printed circuit board for a wire connecting unit having the contact configuration of FIG.  1 . 
     FIG. 8 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a second embodiment of the present invention. 
     FIG. 9 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a third embodiment of the present invention. 
     FIG. 10 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a fourth embodiment of the present invention. 
     FIG. 11 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a fifth embodiment of the present invention. 
     FIG. 12 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a sixth embodiment of the present invention. 
     FIG. 13 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a seventh embodiment of the present invention. 
     FIG. 14 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a eighth embodiment of the present invention. 
     FIG. 15 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a ninth embodiment of the present invention. 
     FIG. 16 is a partial top perspective view of a printed circuit board for a wire connecting unit having a contact configuration according to a tenth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A high density jack  10  for telecommunication systems according to the present invention is schematically or diagrammatically illustrated in FIGS. 1-3. The connector comprises a connector body or housing  12  and a wire connecting unit  14  coupled to the connector body. The wiring unit comprises a printed circuit board  16  on which terminals  18  are mounted. The terminals  18  are standard  110  insulation displacement contacts (IDC), and are coupled to standard wiring as shown specifically in FIG.  2 . Through the circuit board, these terminals are electrically and mechanically coupled to resilient contacts  20 ,  22 ,  24 ,  26 ,  28 ,  30 ,  32  and  34 . The resilient contacts extend into the connector body in a configuration for electrical connection to a conventional or standard plug  36 , particularly an RJ plug. 
     if In the illustrated embodiment, connector body  12  is in a form to form a jack. However, the connector body can be of any desired form, such as a plug, cross connect or any other connector in the telecommunications or data transmission field. 
     Connector body  12  is generally hollow having a forwardly opening cavity  38  for receiving a conventional RJ plug. Eight parallel slots  40  extend through the connector body and open on its rear face. One of resilient contacts  20 - 34  is located in each of the slots. 
     Below slots  40  and remote from plug receiving cavity  38 , the connector body has a recess  42 . Recess  42  opens on the rear face of connector body  12  and is adapted to receive a portion of circuit board  16 , specifically the portion of the circuit board on which the resilient contacts  20 - 34  are mounted. A shelf  44  can extend rearwardly from the connector body below recess  42 . Shelf  44  supports circuit board  16  and facilitates the coupling between the circuit board and the connector body. 
     As seen in FIGS.  4  and  7 - 16 , printed circuit board  16  is divided into a relatively narrower plug connection portion or first area  46  and a relatively wider termination or second area  48 . Plug connection portion  46  is further divided into a relatively narrower nose or first area  50  having a free or distal end  52  and a proximal end  64  and into a relatively wider or second area  56  having a near end  58 . 
     As seen in FIGS.  3  and  5 - 7 , each resilient contact  20 - 34  comprises a proximal end  65 , a base portion  66 , a contact portion  68 , and a distal end  69 . The base portions are received and are electrically connected to the circuit paths provided on the printed circuit board and have a laterally protrusion or push foot mechanism  86  on either one side only as seen on contacts  20 - 28  or on both sides as seen on contact  30  and  32 . The contact portions are substantially parallel and extend in a cantilever manner from the base portions and are bent at an angle for receipt within slots  40  of connector body  12 . As seen in FIGS. 4-6, holes or apertures  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82 , and  84  in printed circuit board  16  provide connections in the circuit board for the resilient contacts  20 - 34  either through traditional solder attachment or compliant pin. The compliant pin technique frictionally fits base portion  66  into the holes in printed circuit board  16 . Both assembly techniques require push foot  86 . 
     Push foot mechanism  86  enables the contacts to be inserted into the printed circuit board  16  with an assembling fixture. To comply with the contact geometry of the standard plug  36  and the annular (plated through) ring geometry requirements in a printed circuit board, the jack contacts must be spaced apart by 0.040 inch. Having a push foot on one side allows the contacts to be positioned laterally in one row on 0.040 inch spacing. By immobilizing the moment of the contact and applying pressure to the single push foot, the contact can be insert into its respective aperture in the circuit board. The closer positioning of the contacts allows greater reduction or cancellation of adjacent Gaussian fields, improving the performance of the connector. 
     Plug connection portion  46  comprises eight holes or apertures  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82 , and  84 . Each of the holes is internally plated with an electrically conductive material, as conventionally done in this art. The holes preferably are arranged in two rows. The first row has one pair of contacts  32  and  34  mounted in the first area of the plug connection portion  46  adjacent the free or distal end  52 . The contacts generally extend perpendicularly to the circuit board and then extend generally upwardly and backwardly toward the wire termination portion  48  at angle of about 60-70 degrees relative to the printed circuit board  16 , as seen in FIGS. 4 and 7. The second row has 3 pairs of contacts  20 ,  22 ,  24 ,  26 ,  28 , and  30  mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64  and extending upwardly and backwardly toward said wire termination portion  56  at angle of about 60-70 degrees relative to the printed circuit board  16 . The contacts in the second row (i.e.  20  and  22 ,  24  and  26 , and  28  and  30 ) each has a single push foot  86  extending laterally and outwardly from the proximal end  65  of its respective contact, away from the other contact in its respective pair of contacts, as seen specifically in FIG.  6 . The two contacts in the first row have push feet or push foot mechanisms extending from both sides of their proximal ends, as seen specifically in FIG.  5 . In this configuration, the physical separation of contacts  30  and  32  enhances the near end cross talk performance. 
     Particularly, contacts  24  and  26  form a first pair and contacts  34  and  36  form a second pair. These first and second pairs, because of their positions, pose the greatest crosstalk problem. The increased separation between these two pair reduces crosstalk problems. 
     Embodiment of FIG. 8 
     As seen in FIG. 8, the contacts can be arranged in two rows of four each, which rows are laterally offset from one another. Specifically, in this configuration, the pairs of contacts are equally split with contacts  120 ,  126 ,  128  and  132  forming a first row of contacts mounted in the first area  50  of the plug connection portion  46  adjacent the free or distal end  52 . Initially, the contacts generally extend substantially perpendicularly to the printed circuit board and then extend generally upwardly and backwardly toward the wire termination portion  48 . Contacts  122 ,  124 ,  130  and  134  form a second row of contacts mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64  and extend upwardly and backwardly toward said wire termination portion  48 . Each contact in the first row of contacts is substantially the same distance from free end  52  as each other contact in the first row. Each contact in the second row of contacts is substantially the same distance from the proximal end  64  as each other contact in the second row. The contacts in this configuration have a similarity of neutral axis length or length measured from the printed circuit board to the point in which the contact mates with the plug. A similarity in neutral axis length optimizes the skew performance of the connectors. 
     The FIG. 8 configuration maximizes the spacing of the contacts in the row and the two contacts of each pair. The spacing in each row facilitates the use of two push feet on each contact. 
     Embodiment of FIG. 9 
     In the embodiment of FIG. 9, the contacts are arranged in a similar dual row configuration as that of the embodiment shown in FIG.  8 . However, in this embodiment, the first row of contacts (i.e. contacts  220 ,  226 ,  228  and  232 ) each extend substantially vertically from the printed circuit board, curve toward the free end  52 , then curve back toward the proximal end  64 , creating a protrusion  288 , before extending back toward the near end  58  of the printed circuit board. Additionally, the second row of contacts (i.e. contacts  222 ,  224 ,  230  and  234 ) each extend substantially vertically from the printed circuit board  16  then curve toward the free end  52  before extending back toward the near end  58  of the printed circuit board. This design creates greater separation between the two rows and increases the neutral axis length or the distance of the contact from the surface of the printed circuit board to the mating point with plug  36 . By lengthening the neutral axis length the contacts can be more accurately tuned, therefore making the electromagnetic interference equal and opposite between pairs of the contacts. However, increasing the neutral axis length increases the compensation created by the electromagnetic field, and therefore the electromagnetic interference induced across the interface is greater than similar configurations. 
     Embodiment of FIG. 10 
     In the embodiment of FIG. 10, the contacts are arranged in a dual row configuration The first row has  3 pairs of contacts  320 ,  322 ,  324 ,  326 ,  328 , and  330  mounted in the first area  50  of the plug connection portion  46  adjacent the distal end  52 . Initially, the contacts extend substantially perpendicularly to the printed circuit board and then extend upwardly and backwardly toward said wire termination portion  48 . The second row has one pair of contacts  332  and  334  mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64  and extend generally upwardly and backwardly toward the wire termination portion  48 . Each contact of the pairs of contacts in the first row (i.e.  320  and  322 ,  324  and  326 , and  328  and  330 ) has a single push foot  86  extending laterally and outwardly from its proximal end  65 , remote from the other contact in its respective pair of contacts. The contacts in the second row have a push foot mechanism extending from each side of their proximal ends  65 . This configuration of contacts provides increase separation between of the pair of contacts  332  and  334 , particularly, relative to the pair of contacts  324  and  326 , reducing unwanted electromagnetic coupling between these two contacts. 
     Embodiment of FIG. 11 
     In the embodiment of FIG. 11, the contacts are arranged in three rows. The first row comprises contacts  422 ,  424 ,  426 , and  428  mounted in the first area  50  of the plug connection portion  46  adjacent the distal end  52 . Initially, the contacts extend substantially perpendicularly to the printed circuit board and then extend upwardly and backwardly toward wire termination portion  48 . The second row has two contacts  420  and  430  mounted in the first area  50  of the plug connection portion  46  adjacent the free or distal end  52 , but further from the distal end then the first row of contacts, and extending generally upwardly and backwardly toward the wire termination portion  48 . The third row has one pair of contacts  432  and  434  mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64  and extending generally upwardly and backwardly toward the wire termination portion  48 . The contacts of the inside pair  424  and  426 , in the first row, each has a single push foot  86  extending laterally and outwardly from its proximal end  65 , remote from the other contact of that pair of contacts. The contacts in the second and third rows have push foots extending from each side of their proximal ends  65 . By forming a contact configuration in this manner, performance is similar to the embodiment in FIG. 10, and electromagnetic coupling between contacts  432  and  434  is reduced due to the separation of these two contacts. 
     Embodiment of FIG. 12 
     The embodiment of FIG. 12 also uses a three row configuration. However, in this configuration, the first row comprises contacts  520 ,  526 , and  528  mounted in the first area  50  of the plug connection portion  46  adjacent the distal end  52 . Initially, the contacts extend substantially perpendicularly to the printed circuit board and then extend upwardly and backwardly toward wire termination portion  48 . The second row comprises contacts  522 ,  524  and  532  mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64 , but further from the proximal end then the third row of contacts, and extend generally upwardly and backwardly toward wire termination portion  48 . The third row comprises the pair of contacts  532  and  534  mounted in the first area  50  of the plug connection portion adjacent the proximal end  64  and extend generally upwardly and backwardly toward the wire termination portion. This configuration performs similarly to the embodiments of FIGS. 10 and 11. 
     Embodiment of FIG. 13 
     In FIG. 13, the contact configuration has a first pair of contacts  620  and  622 , a second pair of contacts  624  and  626 , and third pair of contacts  628  and  630  mounted in a cantilever manner in first area  50  of plug connection portion  46  adjacent free end  52 . Initially, these six contacts extend substantially perpendicularly to the printed circuit board and then extend upwardly and backwardly toward the near end of the plug termination portion. A fourth pair of contacts  632  and  634  is mounted in the second area  56  of the plug termination portion  46  adjacent the near end  58  in a cantilever manner. Contacts  632  and  634  extend upwardly and forwardly toward free end  52 . The first, second and third pairs of contacts extend in a row in which each contact is substantially equidistant from the free end. Each contact in the first, second, and third pairs of contacts has a single push foot  86  extending laterally and outwardly from its proximal end  65 , remote from the other contact in its respective pair of contacts. The contacts in the fourth pair are aligned so that each contact is substantially equidistant from the near end. 
     Contacts  620 ,  622 ,  624 ,  626 ,  628 , and  630  extend at angle of about 60-70 degrees relative to the printed circuit board, in a similar configuration as described above. Contacts  632  and  634 , however, initially extend substantially vertically relative to the printed circuit board and then curve toward the free end at an angle preferably less than 60 degrees. Contacts  632  and  634  then curve downwardly toward the surface of the printed circuit board, forming a protrusion  688 . The protrusion allows the plug to easily mate with contacts  632  and  634  without contacting the distal end of the contacts. 
     This configuration of contacts provides maximum separation between contacts  632  and  634  and the other contacts, reducing unwanted electromagnetic coupling therebetween The physical lay out of contacts  620  and  632  produce a electromagnetic field that is equal and opposite to the field produced by contacts  634  and  630  so each field is canceled out, enabling the electromagnetic coupling to be induced. This configuration also induces backward wave coupling, since the electromagnetic wave is traveling in opposite directions through adjacent contacts. Additionally, return loss is improved due to the fact that each contact in first through third pair of contacts are immediately adjacent its respective pair. 
     Embodiment of FIG. 14 
     The FIG. 14 configuration is similar to the embodiment of FIG. 13, however, contacts  722 ,  724 ,  726  and  728  form an additional row that is adjacent the proximal end  64  of the first area  52  of the plug connection portion  46 . Contacts  720 ,  730 ,  732  and  734  are in the same configuration as that of the embodiment in FIG.  13 . This configuration of contacts provides maximum separation between contacts  732  and  734 , reducing unwanted electromagnetic coupling between these two contacts. The physical lay out of contacts  720  and  732  produce a electromagnetic field that is equal and opposite to the field produced by contacts  734  and  730  so each field is canceled out, enabling the electromagnetic coupling to be induced. This configuration also induces backward wave coupling, since the electromagnetic wave is traveling in opposite directions through adjacent contacts. However, since all the pairs of contacts are not immediately adjacent one another the return loss is not as preferable as the embodiment of FIG.  13 . 
     Embodiment of FIG. 15 
     The embodiment of FIG. 15 is similar to the embodiment of FIG.  14 . Contacts  820 ,  822 ,  824 ,  830 ,  832 , and  834  are placed in a substantially similar configuration as the corresponding contacts of the embodiment of FIG. 14; however, contacts  826  and  828  are positioned closer to the proximal end  64  of the first area  50  of the plug connection portion  46  than contacts  822  and  824 , thus, creating a fourth row of contacts. This configuration performs similarly to the embodiment of FIG.  14 . However, since there is less separation between the contacts at the near end and the contacts at the proximal end  64 , performance is reduced. 
     Embodiment of FIG. 16 
     The FIG. 16 embodiment is similar in configuration to the embodiment of FIG. 12, in that it has three rows. The first row comprises contacts  920 ,  926 , and  928  mounted in the first area  50  of the plug connection portion  46  adjacent the distal end  52  and extending upwardly and backwardly toward wire termination portion  48 . The second row comprises contacts  922 ,  924  and  932  mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64 , but further from the proximal end  64  then the third row of contacts and extending generally upwardly and backwardly toward the wire termination portion  48 . The third row comprises contacts  932  and  934  mounted in the first area  50  of the plug connection portion  46  adjacent the proximal end  64  and extend substantially perpendicularly from the printed circuit board  16 . Contacts  932  and  934  then curve forward toward the free  52  end before curving generally upwardly and backwardly toward the wire termination portion  48 . This configuration performs similarly to the configuration of the embodiments of FIG. 14 and 15, since there is separation between contacts  932  and  934 . However, in this configuration, the contacts extend in a substantially similar direction (i.e. upwardly and backwardly) and therefore, there is no backward wave coupling. 
     Even though some of the configurations do not have the same enhanced performance as other configurations mentioned above, some configurations having shorter contacts, for example, the configurations shown in FIGS. 11,  12 , and  15 , and may be more desirable, since the mechanical layout may improve their performance when deflected to the deflection limits. 
     The features of the contact configurations of the embodiments shown in FIGS. 8-16, which are substantially similar to the embodiment shown in FIGS. 1-7 are identified with like reference numbers. The same description of those similar features is applicable to the embodiments shown in FIGS. 8-16. Additionally, the description of other elements of the wiring unit, such as the printed circuit board, housing, and all other aspects of the wiring unit, apply to the embodiments in FIGS. 8-16. 
     While specific embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.