Abstract:
A high speed lock cross talk modular jack for mating with a plug mounted on the end of a data transmission cable having four pairs of twisted conductors includes wire contacts having cantilever ends extending into a plug recess and contact pins extending below the plug body. Intermediate portions of the wire contacts extending from the cantilever ends to the pins are spread and angled outwardly and the intermediate portions of the center wire contacts cross over each other to reverse the positions of the pins for these contacts.

Description:
FIELD OF THE INVENTION 
     The invention relates to high speed modular jacks of the type mounted on circuit components for mating with plugs on the ends of multi-conductor cables used for transmitting signals between computers. 
     DESCRIPTION OF THE PRIOR ART 
     Modular jacks for forming electrical connections between circuit members and plugs mounted on the ends of multi-conductor data-transmission cables are well known. The cables conventionally have eight conductors arranged in four twisted conductor pairs. The jacks and plugs each have eight contacts to form connections between the eight conductors in the cable and the circuit member. 
     The jacks include a molded plastic body defining a plug recess for receiving a plug mounted on the end of a data transmission cable. Cantilever ends of wire contacts mounted in the body extend into and across the recess to form electrical connections with the contacts on a complimentary plug. The wire contacts run from the recess to pins which extend downwardly from the bottom of the jack. The pins are positioned in preformed holes in the circuit board and are soldered to conductive traces on the circuit board. 
     The cantilever ends of the wire contacts are spaced across the recess in the block and extend from the recess to the pins in side-by-side parallel relationship, without crossing each other. The pins are spaced across the jack in the same sequence as the contacts are spaced across the recess. The pins are arranged in two rows of pins extending across the body with alternate pins in different rows. 
     The industry standard for modular jacks requires that the wire pairs in twisted wire data transmission cables be connected to particular cantilever ends in the plug recess. These ends are spaced across the recess in numerical positions  1  through  8  with the cantilever end  1  adjacent one end of the recess and cantilever end  8  adjacent the opposite end of the recess. The industry standard requires that twisted wires in a first pair of twisted wires must be connected to cantilever ends  1  and  2 . A second pair of twisted wires must be connected to cantilever ends  3  and  6 . A third pair of twisted wires must be connected to cantilever ends  4  and  5  and a fourth pair of twisted wires must be connected to cantilever ends  7  and  8 . Modern high speed computing requires rapid transmission of signals along cables, through the plugs and jacks and to computer circuitry with low cross talk between adjacent circuit paths. EIA/TIA Category  5  standards govern permissible near end cross talk generated by modular jacks used for transmitting signals from 1 to 100 MHz. More stringent Category  6  standards govern near end cross talk in modular jack transmitting signals up to 250 MHz. Conventional modular jacks have difficulty meeting Category  5  cross talk standards and cannot meet Category  6  cross talk standards. 
     Cross talk in conventional signal transmission jacks is believed generated by intermediate portions of the wire contacts which extend along the rear wall of the jack from the cantilever contacts to solder pins at the bottom of the jack. In this type of jack, it is particularly difficult to reduce cross talk between separated contacts  3  and  6  and adjacent contacts which are connected to other signal pairs. 
     Jacks which generate cross talk at high frequency transmission rates may use specialized compensation systems to compensate for inherent cross talk. It is also possible to incorporate special circuitry in the circuit board supporting the jack to compensate for cross talk generated by the jack. Cross talk compensation systems are expensive, complicate manufacture and are not always effective over a desired range of transmission frequencies. 
     Thus, there is a need for an improved jack for transmitting high speed signals with very low near end cross talk. The jack should space the wire conductors extending from the plug recess to the pins to reduce cross talk and should eliminate the need for a specialized cross talk compensation system in the jack. The jack should meet Category  5  near end cross talk standards and should, when mounted on a circuit board with the circuit board traces including a cross talk compensation system, meet Category  6  cross talk standards. 
     SUMMARY OF THE INVENTION 
     The invention is an improved modular jack for high speed data transmission, typically for establishing electrical connections with an end plug on a data cable having four twisted pairs of conductors. The jack generates very little near end cross talk and meets Category  5  near end cross talk standards. The jack may be mounted on a circuit board having conductive traces arranged to compensate for the low level of cross talk generated by the jack. The jack and board are believed to meet Category  6  near end cross talk standards. The jack is preferably mated with a plug generating low cross talk to form a connection system with low cross talk joining an eight conductor cable to electronic circuitry, typically computer circuitry. 
     The jack includes wire contacts with conventional cantilever ends extending into a plug recess in the jack for engaging and forming electrical connections with contacts in an inserted plug. The wire contacts intermediate portions run from the cantilever ends to pins projecting below the bottom of the jack. The pins are arraigned in two rows of pins. An end pin in each row of pins is separated from the remaining three pins in the row with the separated pins positioned on opposite ends of the rows. The intermediate portions of the center two wire contacts in the jack cross over each other at the back of the jack so that the pins for these contacts are arranged out of normal sequence across the jack. The intermediate portions do not parallel each other. 
     In a conventional modular jack, the cantilever ends of the wire contacts are arranged  1 , 2 , 3 , 4 , 5 , 6 , 7 , 8  across the plug recess and the corresponding pins are arranged in spaced staggered rows across the jack in the same  1 , 2 , 3 , 4 , 5 , 6 , 7 , 8  sequence with the even pins in one row and the odd pins in the other row. 
     In the modular jack of the present invention, crossover of the intermediate portions of the center two wire contacts reverses the positions of the center two pins so that the pins are arranged across the jack in spaced, staggered rows in  1 , 2 , 3 , 5 , 4 , 6 , 7 , 8  sequence. 
     The positions of the jack pins and the arrangement of the intermediate portions of the wire contacts reduce cross talk generated by the jack and permit the jack to meet Category  5  standards. 
     In one test, a conventional jack of the type described with pins in the same sequence as the cantilever ends and parallel intermediate portions generated −38 dB of cross talk. In the same test using the jack of the present invention, the cross talk was reduced to −44 dB. 
     Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating the invention, of which there are four sheets and one embodiment. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a modular jack according to the invention; 
     FIG. 2 is a side view of the modular jack taken along line  2 — 2  of FIG. 1; 
     FIG. 3 is a bottom view of the modular jack; 
     FIG. 4 is a partially broken away view of a circuit board showing mounting openings for the modular jack; 
     FIG. 5 is a view similar to FIG. 4 showing a circuit board showing mounting openings for a conventional modular jack; 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG. 1; 
     FIG. 7 is a top view of the insert member and wire contacts; and 
     FIGS. 8 and 9 are sectional views taken along lines  8 — 8  and  9 — 9  of FIG. 5, respectively. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Modular jack  10  includes an insert member  12  and a shell  14  surrounding the member. The jack carries eight shaped wire contacts  16 - 30  for forming electrical connections between eight corresponding contacts of a modular plug inserted into the jack and conductive traces on a circuit board supporting the jack. Pins on the ends of the wire contacts are soldered to conductive traces on the circuit board. Member  12  and shell  14  are molded from a dielectric material, which may be a polyester thermoplastic, although other materials may be used. 
     Jack  10  is generally rectangular or block shaped and includes front wall  32 , rear wall  34 , opposed sidewalls  36  and  38 , open top wall  40  and bottom wall  42 . Plug recess  44  extends into jack  10  through top wall  40  for receiving a modular plug and forming electrical connections between contacts carried by the plug and wire contacts  16 - 30 . 
     Insert member  12  includes a flat base  46  which fits into the bottom of shell  14  to form bottom wall  42 . Contact support member  48  extends above the rear end of base  46  and forms part of rear wall  34 . Member  48  extends across the jack, between the sides of base  46 . The front side of the support member  48  forms part of the rear wall of recess  44 . A first row  49  of contact alignment passages  50 ,  52 ,  54  and  56  extends across member  48  adjacent back wall  34 . A second row  57  of contact alignment passage  58 ,  60 ,  62  and  64  extends across the member  48  between the first row  49  and plug recess  44 . Each of the contact alignment passages  50 - 64  extends vertically along member  48  and includes a large rectangular opening at the top of the member  48 , inwardly sloped sidewalls and a small lower opening at the bottom of the insert member  12 . The lower ends of the wire contacts have sliding fits in the lower ends of the passages so that the lower ends of the wire contacts are held in desired locations on base  46  and form solder pins. The wire contacts are inserted freely into the passages and are guided to the desired locations by the angled passage walls. The passages orient the pin ends of the wire contacts in the pattern illustrated in FIG. 3 for mounting on the circuit board shown in FIG.  4 . 
     As illustrated in FIGS. 7 and 8, in row  57  passage  64  leads wire contact  28  from the top of the support member  48  toward sidewall  36  and passages  58 ,  60  and  62  lead wire contacts  16 ,  20  and  24  in the opposite direction, toward sidewall  38 . As shown in FIGS. 7 and 9, in row  49  passages  52 ,  55  and  56  lead wire contacts  22 ,  26  and  30  toward sidewall  36  and passage  50  leads wire contact  18  in the opposite direction toward sidewall  38 . 
     Support member  48  includes a first contact positioning rib  66  extending along the length of the member  48  between the two rows of contact alignment passages and projecting above the passages. A second contact positioning rib  68  extends along the length of the support member  48  between the inner row  57  of passages and recess  44 . Contact alignment fingers  70  are spaced along the top of rib  68 . 
     Wire contacts  16 - 30  are mounted on insert member  12  as shown in FIG. 7 with the lower ends of the wire contacts extending through the openings at the bottoms of the alignment passages to form contact pins. Each wire contact includes an intermediate portion  71 , shown in FIG. 1, extending from a pin on the bottom of the jack to the top of the support member  48 . Each wire contact is bent around the top of the support member  48 , fitted in a space between a pair of fingers  70  and then extends downwardly into plug recess  44 . The inner ends of the wire contacts angle into the recess and form cantilever contacts or ends  69 . Insertion of a plug into recess  44  bends the cantilever contacts toward the support member  48  to form electrical connections with contacts carried by the plug. 
     Wire contact  16  is inserted in alignment passage  58  to form pin  72  projecting below base  46 . Contact  16  extends upwardly from passage  58 , is bent around rib  68 , extends between two fingers  70  and is angled down from the rib  68  to form a cantilever contact  69 . 
     Wire contacts  20 ,  24  and  28  are inserted into remaining alignment passages  60 ,  62  and  64  in row  57  to form pins  74 ,  76  and  78  extending below base  46 . Contacts  20 ,  24  and  28  extend upwardly from their respective passages, are bent around rib  68  and extend between two fingers  70  to form cantilever contacts  69  angling down from the top of support member  48 . Each contact is located in position on the rib  68  by a pair of adjacent fingers  70 . 
     Contacts  18 ,  22 ,  26  and  30  are likewise extended into passages  50 ,  52 ,  54  and  56  in row  49  to form pins  80 ,  82 ,  84  and  86 , respectively, extending below base  46 . The upper portions of these contacts are bent around ribs  66  and  68 , positioned between two fingers  70  on rib  68  and extend into recess  44 . The eight cantilever contacts  69  are held on rib  68  in industry standard center-to-center spacing X of 0.040 inches for engaging corresponding contacts carried by a plug inserted into recess  44 . Spacing X is shown in FIG.  1 . 
     Latches  88  extend outwardly from the sides of support member  48  and engage openings or windows  90  formed on the opposite sides of shell  14  to secure the shell  14  to the insert member  12 . See FIG.  9 . 
     Shell  14  includes a pair of circuit board latches  92  extending downwardly from opposite sides of the shell for securing jack  10  on a circuit board. 
     Shell  14  includes floor  94  forming the bottom of recess  44  and extending across the recess  44  from the front of the jack to support member  48 . Slots  96  are formed in the forward end of floor  94  adjacent the support member  48  and are spaced along the support member  48  to receive the ends of the cantilever contacts  69  extending into recess  44 . The wire contacts are biased outwardly into the recess  44  so that the lower ends of the contacts engage the ends of the slots as shown in FIG.  6 . Corresponding contact slots  98  are formed across the top of the support member  48  adjacent the recess  44  and facilitate orienting the cantilever contacts in the jack. Fingers  70  and slots  96  and  98  assure that the cantilever contacts extend into recess  44  for engagement with contacts on a plug inserted into the recess. 
     Insert member  12  with wire contacts mounted in the member  12  as described, is inserted into shell  14  by extending the support member  48  into the shell between the rear wall and floor  94  with the cantilever ends of the wire contacts each positioned in a slot  96 . With the insert fully seated in the shell, base  46  is flush against floor  94  and windows  90  have snapped over latches  88  to secure the insert member  12  and shell together, as illustrated in FIG.  9 . The member  12  and shell form a jack body. 
     A row of fingers  100  extend downwardly from shell top wall  102  above rib  68 . Fingers  100  cooperate with fingers  70  to assure that the wire contacts extending across the ribs  66  and  68  are held in proper position. Top wall  102  is spaced from the top and rear side of positioning rib  66  a distance slightly greater than the thickness of the wire contacts to assure the contacts are held closely against the rib. See FIG.  6 . 
     FIG. 8 illustrates the contact alignment passages  58 ,  60 ,  62  and  64  in the second passage row  57  and the intermediate portions  71  of wire contacts  16 ,  20 ,  24  and  28  extending through the passages. The intermediate portions of the remaining wire contacts extending through the first row of passages  49  are shown in dashed lines. The intermediate portions  71  of wire contacts  16 ,  18  and  20 , and  26 ,  28 , and  30  led from the top of the support member  48  down to the terminal pins are angled and spread apart across the width and depth of the jack as illustrated in FIGS. 7-9. The intermediate portions of the center two contacts  22  and  24  cross each other at the center of the support member  48  and are angled and spread. 
     In row  57 , the intermediate portions of the three wire contacts  16 ,  20  and  24  adjacent jack side  38  are all angled from the top of the support member  48  toward side  38  so that pins  72 ,  74  and  76  are located nearer side  38  than the cantilever contacts  69  on the other ends of the wire contacts. The pins are spaced apart 0.100 inches, greater than the 0.040 inch spacing of the cantilever contacts. The intermediate portion of contact  28  is bent toward jack side  36  to locate pin  78  adjacent side  36  and space pin  78  a distance of 0.200 inches from adjacent pin  76  in row  57 , twice the spacing between the remaining pins in the row. 
     Likewise, in row  49  the intermediate portions of wire contacts  22 ,  26  and  30  are spread and angled toward jack sidewall  36  to form pins  82 ,  84  and  86  spaced apart by 0.100 inches. The intermediate portion of wire contact  18  is bent towards jack sidewall  38  to form pin  80  which is adjacent wall  38  and spaced from adjacent pin  82  by 0.200 inches. FIGS. 7 and 9 illustrate the non-parallel spacing of the intermediate portions along the back of support member  48 . 
     The intermediate portions of the center two wire contacts  22  and  24  are positioned in passages  52  and  62  in rows  49  and  57 , and form pins  82  and  76  respectively. Pins  76  and  82  are spaced further apart between the jack sidewalls than the wire contacts  22  and  24  at the top of the support member  48 . 
     The arrangement of the pins extending below the bottom of jack  10  is shown in FIG.  3 . The pins are arranged in two spaced staggered rows  104  and  106  extending across the rear portion of the modular jack. Outer row  106  is located between inner row  104  and rear wall  34 . The outer row  106  of pins includes single end pin  80  adjacent sidewall  38  and three equally spaced apart or adjacent pins  82 ,  84  and  86  near sidewall  36 . The inner row  104  of pins includes a single end pin  78  near sidewall  36  and three equally spaced apart or adjacent pins  76 ,  74  and  72  near sidewall  38 . Adjacent pins  72 ,  74  and  74 ,  76  in row  104  and  82 ,  84  and  84 ,  86  in row  106  are spaced apart a distance Y of 0.100 inches. The spacing Z between separated pins  76 ,  78  in row  104  and pins  80  and  82  in row  106 , is twice the adjacent pin spacing, or 0.200 inches. The spacing between the two rows is 0.100 inches. The spacing between the pins measured in a direction along the rows is 0.050 inches from pin  72  to pin  80 ; 0.050 inches from pin  80  to pin  74 ; 0.100 inches from pin  74  to pin  76 ; 0.050 inches from pin  76  to pin  82 ; 0.100 inches from pin  82  to pin  84 ; 0.050 inches from pin  84  to pin  78 ; and 0.050 inches from pin  78  to pin  86 . 
     As illustrated in FIG. 3, adjacent pins  82  and  84  in row  106  are located between end pin  78  and pin  76  in row  104 . Also, the two adjacent pins  74  and  76  in row  104  are located between end pin  80  and adjacent pin  82  in row  106 . 
     FIG. 4 illustrates circuit board  108  for mounting modular jack  10 . The jack is mounted on the board by positioning latches  92  over latch holes  110  and moving the jack toward the board to extend the pins into numbered pin holes  1 - 8 . The arrangement of pin holes  1 - 8  on board  108  corresponds to the positions of the pins extending from the jack as shown in FIG.  3 . 
     The arrangement of pin holes  1 - 8  on board  108  differs from the arrangement of pin holes  1 - 8  on prior art circuit board  112  used to mount a conventional modular jack where the wire contacts are not spread apart between the side walls as in the present invention and the intermediate portions of the center two wire contacts  22 ,  24  do not cross each other to reverse the positions of the pins for the center wire contacts. 
     In modular jack  10  the wire contact pins are arranged in two rows  104  and  106 . As illustrated in FIG. 3, these rows are straight and parallel each other. The corresponding pin holes formed in circuit board  108  of FIG. 4 are also arranged in two straight and parallel rows. However, the invention is not limited to wire contact pins and pin holes which are arranged in straight rows or in spaced, parallel rows. The pins, and corresponding pin holes, may be arranged in non-straight rows, and the rows need not parallel each other. 
     While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.