Modular electrical plug, plug-cable assemblies including the same, and load bar and terminal blade for same

[0002] This application is related to U.S. provisional application Ser. No. 60/136,178, filed May 27, 1999.

[0003] This invention relates generally to modular electrical plugs and, more particularly, to a modular plug having performance properties which will be in compliance with Category 6 standards.

[0004] The present invention also relates to plug-cable assemblies of a multi-conductor cable and a plug at one end terminating the cable and a plug or other electrical connector terminating the other end of the cable, or the other end being unterminated.

[0005] The present invention also relates to a load bar and a terminal blade for a modular electrical plug.

[0006] In view of the continual desire to increase the transmission rate of data through electrical cables, new performance standards are being promulgated for modular electrical connectors. Connectors having characteristics in compliance with this standard will be known as Category 6 connectors, or Cat 6 connectors for short.

[0007] Although existing modular connectors such as jacks and plugs, e.g., those having characteristics in compliance with the immediate lower standards (Category 5), might be found to be in compliance with Category 6 standards as well, it is advantageous to develop new modular connectors designed specifically to comply with Cat 6 standards.

[0008] Cat 6 modular jacks and plugs are intended to be used in data communication networks to enable the flow of information at higher transmission rates than currently available with known modular connectors, including Cat 3 and Cat 5 connectors. However, data transmitted at high rates in multi-pair data communication cables has an increased susceptibility to crosstalk, which often adversely affects the processing and integrity of the transmitted data. Crosstalk occurs when signal energy “crosses” from one signal pair to another. The point at which the signal crosses or couples from one set of conductors to another may be 1) within the connector or internal circuitry of the transmitting station, referred to as “near-end” crosstalk, 2) within the connector or internal circuitry of the receiving station, referred to as “far-end crosstalk”, or 3) within the interconnecting cable.

[0009] Near-end crosstalk (“NEXT”) is especially troublesome in the case of telecommunication connectors of the type specified in sub-part F of FCC pan 68.500, commonly referred to as modular connectors. The EIA/TIA (Electronic/Telecommunication Industry Association) of ANSI has promulgated electrical specifications for near-end crosstalk isolation in network connectors to ensure that the connectors themselves do not compromise the overall performance of the unshielded twisted pair (UTP) interconnect hardware typically used in LAN systems. It is expected that electrical specifications for Cat 6 plugs will also be promulgated in the near future.

[0010] In the prior art, reference is made to the assignee's U.S. Pat. No. 5,628,647 (Rohrbaugh et al., incorporated by reference herein) which describes Cat 5 modular plugs including a management bar or load bar for receiving the conductors in separate conductor-receiving passages or channels. Inter-conductor capacitance in the plugs is reduced by offsetting adjacent conductors, i.e., vertically spacing adjacent conductors from one another, such that the conductor-receiving channels, and thus the conductors, are arranged in two planar arrays spaced one above the other. The offset conductors help to lower the plug's internal capacitance thus enabling compliance with, for the disclosed plugs, Cat 5 standards.

[0011] It is an object of the present invention to provide new and improved modular plugs and modular plug-cable assemblies including the same.

[0012] It is another object of the present invention to provide new and improved modular plugs and modular plug-cable assemblies including the same in compliance with Category 6 standards.

[0013] It is yet another object of the present invention to provide new and improved designs of modular plugs offering crosstalk performance better than that of existing modular plugs.

[0014] It is still another object of the present invention to provide a new and improved conductor management bar or load bar for use in modular electrical plugs.

[0015] It is another object of the present invention to provide new and improved terminal blades for use in modular electrical plugs.

[0016] Briefly, in accordance with the present invention, these and other objects are achieved by providing a modular plug including a plug housing made of dielectric material including a plurality of parallel, spaced, longitudinally extending terminal-receiving slots at a forward end and a longitudinal cavity extending from a rear face thereof forward to a location below the slots such that the cavity is in communication with the slots. Each terminal-receiving slot receives a respective terminal blade or insulation displacing contact. The plug also includes a conductor management bar, or load bar, arranged in the cavity and defining conductor-receiving channels in which the two channels receivable of the conductors forming conductor pair #3, i.e., conductors 3 and 6 according to TIA/EIA-ANSI standard 568B, are located in a first row or level while the two channels receivable of the conductors forming conductor pair #1, i.e., conductors 4 and 5 according that standard, are located in a second row or level substantially parallel to and spaced from the first level. Preferably, the channels receivable of conductors 4 and 5 are spaced laterally inwardly, i.e., between the channels receivable of conductors 3 and 6.

[0017] In a first preferred embodiment comprising an 8-position plug (terminating four twisted wire pairs), the conductor-receiving channels are located in three substantially parallel rows or levels arranged such that each level receives at least one pair of conductors operatively forming a circuit during use. The channels adapted to receive the conductors forming conductor pair #1, conductors 4 and 5, and the channels adapted to receive the conductors forming conductor pair #3, conductors 3 and 6, are situated in the levels most distant from one another to thereby reduce crosstalk between these conductor pairs. The two additional pairs of channels are situated at a third intermediate level between the first and second levels.

[0018] More particularly, according to a first embodiment of the invention, the load bar housing includes first (or rearward), second (or intermediate) and third (or forward) longitudinally adjoining portions, the third portion being situated below the contact-receiving slots and each portion having a different transverse cross-sectional form, although the load bar housing is a unitary member. At one (a top) level, two channels are formed from, a longitudinal indentation or trough on an upper surface of the first (or rearward) portion, a shaped cavity or bore in the second or intermediate portion and a longitudinal indentation or trough on an upper surface of the third portion). A groove is provided in the first and second portions to receive a conductive strip and hold the conductive strip between the channels in the first level and thereby correct an impedance problem arising from the horizontal separation of the conductors received in the channels in this level. At a second (a bottom) level, two channels are formed from a respective longitudinal indentation on a lower surface of the first portion, a shaped cavity in the second portion and a respective indentation on an upper surface of the third portion. At a third (an intermediate) level, two additional pairs of channels are formed within the load bar housing and between the first and second levels. The load bar assembly preferably comprises means for distributing crosstalk between the pairs of conductors received in the channels in the third level and the pairs of conductors received in other channels and operatively forming a circuit during use, i.e., conductive strips situated alongside the channels.

[0019] The conductive strips may be strips of metallic material such as copper, strips of conductive plastic, strips of insert molded plastic surrounding a metal strip or an electroplated strip of plastic, i.e., plastic overlaid with metal.

[0020] A second embodiment of the invention comprises an 8-position plug that does not require three separate levels of conductor-receiving channels in the plug housing. According to the second embodiment, the load bar assembly includes a load bar housing defining a plurality of longitudinally-extending conductor-receiving channels for receiving conductors of the cable in which, like the case of the first embodiment, the two channels receivable of the conductors designated 3 and 6 forming conductor prior #3 are located in a first top row or level while the two channels receivable of the conductors 4 and 5 forming conductor pair #1 are located in a second or bottom row or level substantially parallel to and spaced from, and are between the channels in, the first level and between the channels in the first level. The second embodiment differs from the first embodiment in that two additional pairs of channels receivable of the other conductors forming the other two conductor pairs are situated in the same level as that in which the channels receivable of conductors 4 and 5 forming conductor pair #1 are located, i.e., the bottom level. The load bar housing of this embodiment also includes three longitudinally adjoining portions, and the channels are formed in the load bar housing by an arrangement of indentations or troughs and shaped cavities or bores similar, but not identical to the arrangement in the first embodiment. An elongate conductive strip arranged between two channels receiving two conductors operatively forming a circuit during use. The load bar housing preferably also includes a groove parallel to and between these two channels in which the conductive strip is arranged.

[0021] In another embodiment of the plug in accordance with the invention which does not require three separate levels of conductor-receiving channels in the plug housing (although it is a preferred construction), the plug includes a housing defining a plurality of terminal-receiving slots and a longitudinal cavity extending from a rear surface of the housing, terminal blades arranged in the slots and a load bar assembly including a load bar housing defining a plurality of conductor-receiving channels for receiving the conductors of the cable and guiding the conductors to a location below the slots such that the terminal blades are displaceable to penetrate the conductors when the conductors are received in the channels. Further, the load bar assembly includes means for distributing, within the pair of conductors received in one pair of channels and operatively forming a circuit during use, crosstalk generated between that pair of conductors and pairs of conductors received in other channels. The longitudinal cavity may extend from the rear surface of the housing to a location below the slots and be in communication with the slots whereby the load bar assembly would extend in the cavity to a location below the slots.

[0022] The modular plug-cable assembly in accordance with the invention includes a multi-conductor cable and at least one plug as described above terminating a respective end of the cable. The other end of the cable may be terminated by a plug as described above or another electrical connector, or left unterminated. In the latter case, the purchaser of the plug-cable assembly could terminate the unterminated end as desired.

[0023] A load bar for a modular plug in accordance with the invention includes a unitary housing defining a plurality of channels arranged in at least two substantially parallel levels whereby each level includes at least two channels. The housing is elongate and includes first, second and an optional third longitudinally adjoining portions each having a different cross-sectional form. In a first three-level 8-position embodiment, each of two channels for receiving conductors 3 and 6 of conductor pair #3 are defined by a longitudinal indentation on an upper surface of the first portion, a cavity in the second portion and an indentation on an upper surface of the third portion and these channels constitute a first level of channels. The housing also preferably includes retaining means for retaining at least one conductive strip, e.g., a groove arranged between the channels in the first portion and the cavities in the second portion. Two additional channels for receiving conductors 4 and 5 of conductor pair #1 are defined by a respective longitudinal indentation on a lower surface of the first portion, a cavity in the second portion and a respective indentation on an upper surface of the third portion and constitute a second level of channels. These channels are preferably arranged between the channels in the first level in a transverse direction of the housing. Further, for the third level, two additional pairs of channels are situated at a common level between the first and second levels of channels. The housing preferably includes means for retaining at least one conductive strip between the channels for conductors forming a circuit pair, such as two pair of longitudinally-extending grooves formed in the first and second portions alongside the channels in the third level.

[0024] In a second two-level 8-position embodiment of the load bar, each of two channels for conductors 3 and 6 of pair #3 are defined at a first or upper level by a longitudinal indentation or trough extending on an upper surface of a first portion and extending partially into the second portion, a shaped cavity or bore extending through the remainder of the second portion and an indentation or trough extending on the upper surface of the third portion. Similar conductive strip retaining means are provided for retaining a conductive strip between the two channels in the upper level. Each of two additional channels for receiving conductors 4 and 5 of conductor pair #1 are defined at a second or bottom level by a shaped cavity or bore extending through the first and second housing portions and an aligned indentation or trough extending on the upper surface of the third portion. These channels are preferably arranged between the channels in the first level in a transverse direction of the housing. Further, two additional pairs of channels for the conductors of pairs #2 and #4 are situated in the second or bottom level. These channels are also formed by shaped cavities or bores extending through the first and second housing portions and aligned indentations or troughs extending on the upper surface of the third portion.

[0025] A terminal blade for a modular plug in accordance with the invention comprises a flat conductive member having a first portion having an upper edge surface adapted to contact a contact of a mating electrical connector, a second portion adjoining the first portion and having a narrow length than the first portion and a third portion adjoining the second portion and having insulation-piercing tines. A notch is defined in the upper surface to partition the upper surface into two sections, each defining a side of the notch.

[0026] A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily understood by reference to the following detailed description when considered in connection with the accompanying drawings in which:

[0027] FIG. 1 is a side view in partial section of a first three-level embodiment of a modular plug in accordance with the invention terminating a cable;

[0028] FIG. 1A is an enlarged view of a terminal blade of the modular plug shown in FIG. 1;

[0029] FIG. 2 is a cross-sectional view of the plug shown in FIG. 1 taken along the line 2—2 of FIG. 1;

[0030] FIG. 3 is a cross-sectional view of the first three-level embodiment of the plug shown in FIG. 1 taken along line 3—3 of FIG. 1;

[0031] FIG. 4 is a cross-sectional view of the first embodiment of the plug shown in FIG. 1 taken along the line 4—4 of FIG. 1;

[0032] FIG. 5 is a cross-sectional view of the first embodiment of the plug shown in FIG. 1 taken along the line 5—5 of FIG. 1;

[0033] FIGS. 3a, 4aand 5aare views of a second two-level embodiment of a plug in accordance with the invention corresponding to the views of the first embodiment shown in FIGS. 3, 4 and 5;

[0034] FIG. 6 is a side view of a plug housing of the first three level embodiment of the plug shown in FIG. 1, a side view of a plug of the second two-level embodiment being substantially the same;

[0035] FIG. 7 is a bottom view of the plug housing shown in FIG. 6, a bottom view of a plug of the second embodiment being substantially the same;

[0036] FIG. 8 is a top view of the plug housing shown in FIG. 6, a top view of a plug of the second embodiment being substantially the same;

[0037] FIG. 9 is a front view of the plug housing shown in FIG. 6, a front view of a plug of the second embodiment being substantially the same;

[0038] FIG. 10 is a rear view of the plug housing of the first three-level embodiment of the invention;

[0039] FIG. 10ais a rear view of the plug housing of the second two-level embodiment of the invention;

[0040] FIG. 11 is a cross-sectional view of the plug housing of the first embodiment shown in FIG. 6 taken along the line 11—11 of FIG. 8;

[0041] FIG. 12 is a cross-sectional view of the plug housing of the first three-level embodiment of the invention taken along the line 12—12 of FIG. 6;

[0042] FIG. 13 is a top perspective view of a first three-level embodiment of a load bar assembly forming a part of the first embodiment of the plug shown in FIG. 1;

[0043] FIG. 14 is a bottom perspective view of the first three-level embodiment of the load bar assembly shown in FIG. 13;

[0044] FIG. 15 is a top perspective view of a first three-level embodiment of a load bar assembly forming a part of the first embodiment of the plug shown in FIG. 1;

[0045] FIGS. 12a-14aare views of the second two-level embodiment of a load bar assembly in accordance with the invention corresponding to the views of the first embodiment of FIGS. 12-14;

[0046] FIG. 15ais an exploded perspective view of the second two-level embodiment of the load bar assembly shown in FIG. 13a;

[0047] FIG. 16 is a left side view of the first three-level embodiment of the load bar assembly shown in FIG. 13;

[0048] FIG. 17 is a front view of the first three-level embodiment of the load bar assembly shown in FIG. 13;

[0049] FIG. 18 is a rear view of the first three-level embodiment of the load bar assembly shown in FIG. 13;

[0050] FIG. 19 is a top view of the first three-level embodiment of the load bar assembly shown in FIG. 13;

[0051] FIG. 20 is a bottom view of the first three-level embodiment of the load bar assembly shown in FIG. 13;

[0052] FIG. 21 is a cross-sectional view of the first three-level embodiment of the load bar assembly shown in FIG. 13 taken along the line 21—21 of FIG. 16;

[0053] FIG. 22 is a partial cross-sectional view of the first three-level embodiment of the load bar assembly shown in FIG. 13 taken along line 22—22 of FIG. 16; and

[0054] FIGS. 17a-22aare views of the second two-level embodiment of a load bar assembly in accordance with the invention corresponding to the views of the first embodiment of FIGS. 17-22.

[0055] Referring now to the drawings wherein like reference characters designate identical or corresponding parts throughout the several views, a modular plug in accordance with the present invention is designated generally as 10 and comprises a plug housing 12 defining a longitudinal cavity 14 opening at a rear face and terminal-receiving slots 16 at the front end, a management bar or load bar assembly 18 arranged in the cavity 14 of the plug housing 12 and including channels 44 for receiving conductors of a cable 8 terminated by the plug 10, and a plurality of terminal blades or insulation displacing contacts 20 arranged in terminal-receiving slots 16 in the plug housing 12.

[0056] Plug 10 has the dimensions of a standard RJ45 plug adapted to terminate an eight-conductor cable 8, i.e., eight terminal-receiving slots 16 each containing a terminal blade 20 (FIG. 2). However, it is within the scope of the invention that the dimensions of the plug 10 may be other than that of an RJ45 plug and/or the construction of the plug may be such that it is adapted to terminate a cable having a different number of conductors.

[0057] Each terminal blade 20 may have the form disclosed in the assignee's U.S. Pat. No. 4,679,878 (Volk), incorporated by reference herein. In the alternative, one or more of the terminal blades 20 may have the form shown in FIG. 1A. As shown in FIG. 1A, the terminal blade 20 includes a notch 20aformed in the upper edge surface 20bto thereby partition the upper edge surface into two sections 20b1,20b2. The depth and width of the notch 20amay vary from that shown but must be selected in consideration of maintaining the functionality of the terminal blade 20. The purpose of the notch 20ais to lower the capacitance of the terminal blade 20 by reducing its side surface area by virtue of the presence of the notch 20a. It is important though that the notch 20apartition the upper edge surface 20binto sections so that at least two sections of the upper edge surface remain because the two sections 20b1,20b2 of the upper edge surface 20benable the use of conventional tooling for pressing the terminal blades 20 into the conductors during termination of a cable by the plug.

[0058] The plug housing 12 is shown in detail in FIGS. 6-12. Plug housing 12 has a front face 22, a rear face 24, a top face 26, and a bottom face 28, the longitudinal cavity 14 opening into the rear face 24. Plug housing 12 also includes a strain relief element 34 formed in conjunction with the top face 26 and a latch 36 projecting from the bottom face 28 for enabling mating with another electrical connector such as a modular jack. The terminal-receiving slots 16 are formed at the front of the plug housing 12 parallel to and spaced from one another and extend downward from the top face 26 (FIGS. 8 and 11).

[0059] As shown in FIG. 11, cavity 14 in the plug housing 12 has a particular shape to accommodate the load bar assembly 18. Specifically, in a longitudinal direction of the plug housing 12, cavity 14 has a rearward portion 14ahaving a substantially rectangular cross-section adapted to receive a rearward end of the load bar assembly 18, an intermediate portion 14bimmediately inward of the rearward portion 14aand a forward portion 14csituated below the terminal-receiving slots 16 (FIG. 11). The intermediate and forward portions 14b,14cof the cavity 14 are constructed to receive a forward end of the load bar assembly 18. While an interior surface 30 of the plug housing 12 defining a bottom surface of the cavity 14 is generally planar, the shape and orientation of an interior surface 32 defining an upper surface of cavity 14 vary between the portions 14a,14b,14c. In the rearward portion 14aof the cavity 14, the upper surface 32 slopes inward toward the bottom surface 30 and continues sloping inward into the intermediate portion 14b. The strain relief element 34 has a lower surface 34adefining part of the upper surface 32 of the rearward portion 14cof the cavity 22. In the forward portion 14cof cavity 14, apertures 38 are formed in the upper surface 32 in communication with the terminal-receiving slots 16 (FIG. 11).

[0060] A plug and its components according to a first embodiment of the invention in which the conductor-receiving passages are arranged in three parallel rows or levels will now be described. In this connection reference is made to FIGS. 1-22 (all these figures without an “a” suffix) which illustrate the first three-level embodiment of the invention.

[0061] The plug housing is specially adapted to receive a load bar 18 which positions the conductors in three levels and in accordance with other aspects of the invention. Referring in particular to FIGS. 10 and 12, the upper surface 32 in the forward portion 14cof the plug cavity is formed to cooperate with the three levels of conductor-receiving channels 44 in the load bar 18 to retain the conductors of the cable 8 therebetween. To this end, the upper surface 32 includes a plurality of arcuate portions 42_1-8the curvature of which is determined by the position of the conductor contacting the arcuate portion 42_1-8. Since the load bar assembly 18 is designed to retain the conductors of the cable 8 in three different planes (discussed in detail below), the arcuate portions 42_1-8of the upper surface 32 are designed similarly at three different spatial separations from the planar bottom face 30 of the cavity 14. In particular, arcuate portions 42₃and 42₆(those situated to overlie the conductors designated 3 and 6 of the cable, not shown) are situated at the largest distance from the bottom face 30 (D1 being the distance between the bottom face 30 and the farthest area of the arcuate portion therefrom), arcuate portions 42₄and 42₅(those situated to overlie the conductors designated 4 and 5 of the cable, not shown) are situated at the shortest distance from the bottom face 30 designated D3, and arcuate portions 42₁, 42₂, 42₇and 42₈(those situated to overlie the conductors designated 1, 2, 7 and 8 of the cable, not shown) are situated at an intermediate distance from the bottom face 30 designated D2. As a result of the different spacing of the arcuate portions 42_1-8from the bottom face 30, the depth of the terminal-receiving slots 16 varies with the deepest slots 16₄, 16₅communicating with the arcuate portions 42₄and 42₅, the shallowest slots 16₃, 16₆communicating with the arcuate portions 42₃and 42₆and the slots 16₁, 16₂, 16₇, 16₈communicating with the arcuate portions 42₁, 42₂, 42₇and 42₈having an intermediate depth (FIG. 12). In the illustrated embodiment, the upper surface 32 is symmetrical about its center line C. A tapering surface 46 having the same general curvature as each arcuate portion 42_1-8is provided rearward thereof to facilitate entry of the conductors of the cable 8 into the forward portion 14c(FIG. 11).

[0062] By means of such construction of the arcuate portions 42_1-8of the upper surface 32 of the forward portion 14cof the cavity 14 of the plug housing 12, and the construction of the load bar assembly 18 described below, the conductors of the cable 8 designated 3 and 6 will lie maximally spaced from the conductors designated 4 and 5 and as such, crosstalk between these conductor pairs is minimized.

[0063] The load bar assembly 18 is shown in detail in FIGS. 13 and 14 and includes a load bar housing 40 and bars or strips of an electrically conductive metallic material 48,50. Conductive strip 48 is elongate and is arranged in a longitudinal channel 52 defined in a center of the load bar housing 40 (FIG. 13). Channel 52 has a width substantially the same as the width of conductive strip 48 and a depth greater than the thickness of conductive strip 48 to avoid projection of the conductive strip 48 above the top surface of the load bar housing 40. The depth of the channel 52 is preferably determined to ensure that the conductive strip 48 will be situated between channels 44₃and 44₆The purpose of the interposition of a metallic element such as conductive strip 48 between these channels, which will receive the conductors designated 3 and 6 forming a conductor pair, is to correct an impedance problem during use of the plug. That is, in view of the separation of conductors 3 and 6 when situated in channels 44₃and 44₆, respectively, the return loss is poorer and the presence of conductive strip 48 will compensate for the return loss. Conductive strip 48 may be fixed in channel 52 or movably arranged therein. Referring to FIG. 14, conductive strips 50, of which there are two, are substantially U-shaped and are arranged one on each side of the load bar housing 40. Conductive strips 50 thus have a flat portion 50aand projecting portions 50bextending from the transverse edges of the flat portion 50aand which are substantially parallel to one another. To accommodate conductive strips 50, two pair of parallel, longitudinally-extending grooves 54a,54bare formed in the lower surface [56] 76 of the load bar housing 40 and receive the projecting portions 50bof the conductive strips 50 (FIG. 14). Conductive strips 50 are thus situated adjacent the lower surfaces 58′,58″ of the load bar housing 40 and partially surround the channels 44₁,44₂,44₇,44₈which receive conductors 1, 2, 7 and 8, respectively, of the cable 8 terminated by the plug 10. The conductive strip 50 partly surrounding conductors 1,2 will operatively function to distribute crosstalk between the pair of conductors 1,2 and the other pairs of conductors and the conductive strip 50 partially surrounding conductors 7,8 will operatively function to distribute crosstalk between the pair of conductors 7,8 and the other pairs of conductors. Conductive strips 48,52 may be formed from foil and may be integrated into the load bar housing 40 or the plug housing 12.

[0064] The first embodiment of the load bar housing 40 is shown in FIGS. 15-22 and is made of a dielectric material. Load bar housing 40 is elongate having a length approximately coextensive with cavity 14. Load bar housing 40 has a rearward portion 40aadapted to be received in the rearward portion 14aof the cavity 14 of the plug housing 12, an intermediate portion 40badapted to be received in the intermediate portion 14bof the cavity 14 and a forward portion 40cadapted to be received in the forward portion 14cof the cavity 14. Channel 52 is formed in the upper surfaces 56′,56″ of the rearward and intermediate portions 40a,40bof the load bar housing 40 (FIG. 13). Grooves 54a,54bare formed in the lower surfaces 58′,58″ also of the rearward and intermediate portions 40a,40bof the load bar housing 40 (FIG. 14). Grooves 54acommunicate with the channels 44₃and 44₆(FIG. 22). Grooves 54bextend to the rear edge of the load bar housing 40 (FIG. 14). A step 60 (FIG. 13) is formed between the forward and intermediate portions 40c,40bwhich, upon insertion of load bar assembly 18 in the cavity 14, will abut against a shoulder 60adefined between intermediate and forward cavity portion 14band 14c(FIG. 11).

[0065] Load bar housing 40 further includes a “hinge” to enable rotational movement of the rearward portion 40arelative to the intermediate and forward portions 40b,40c. This movement may be realized once the load bar assembly 18 is inserted into the cavity 14 and the forward portion 40cof the load bar 40 is fixed within the forward portion 14cof the cavity 14. To this end, the load bar housing 40 includes aligned transverse slits 62 on both the upper and lower sides. The presence of slits 62 allows the rearward portion 40aof the load bar housing 40 to flex with respect to the intermediate and forward portions 40b,40c. Also, the conductive strips 50 are provided with notches 50′ on each side in alignment with the slits 62 to reduce their rigidity and facilitate the flexure of the load bar housing 40 (FIG. 14).

[0066] The channels 44₁, . . . , 44₈in the load bar housing 40 are constructed in a particular manner to position the conductors of the cable terminated by the plug 10 in three different planes. Channels 44₁, . . . , 44₈extend from one edge of the load bar housing 40 to the other edge. The channels 44₁, . . . , 44₈are numbered in sequence from left to right and the number corresponds to the designated number of the conductor of the cable 8 received in that channel. Channels 44₁and 44₂are situated alongside one another and formed by a shaped body or cavity 64 (FIGS. 14 and 22) in the load bar housing 40 extending through the rearward portion 40aand intermediate portion 40b. In the forward portion 40c, the channels 44₁and 44₂are each defined by an arcuate indentation or trough 66 of the upper surface 56′″ of the load bar housing 40 (FIG. 21). Channels 44₃and 44₆are each formed by a longitudinal indentation or trough 68 in the upper surface 56′ of the rearward portion 40aof the load bar housing 40, a shaped cavity or bore 70 in the load bar housing 40 extending through the intermediate portion 40band an indentation or trough 72 of the upper surface 56′″ of the forward portion 40c(FIG. 15). Channels 44₄and 44₅are situated alongside one another and formed by indentations or troughs 74 in the lower surface 76 of the rearward portion 40a(FIG. 14), a cavity or bore 78 in the load bar housing 40 extending through the intermediate portion 40aand indentations 80 of the upper surface 56′″ of the forward portion 40c. Channels 44₇and 44₈are situated alongside one another and formed by a closed cavity or bore 82 in the load bar housing 40 extending through the rearward portion 40aand intermediate portion 40b. In the forward portion 40c, the channels 44₇and 44₈are each defined by an open arcuate indentation 84 of the upper surface 56′″ of the load bar housing 40 (FIG. 21). Instead of forming channels 44₄and 44₅on the lower surface 76 of the load bar housing 40, it is also possible to form these channels within the load bar housing 40.

[0067] Thus, channels 44₁, . . . , 44₈are arranged in three different, substantially parallel levels. Channels 44₃and 44₆are arranged at a first level L1 (the “level” being represented by a plane passing through the central axes of the channels 44₁, . . . , 44₈) which will be nearest the top face 26 of the plug housing 12, channels 44₁, 44₂, 44₇and 44₈are arranged at second level L2 below the first level L1 and channels 44₄and 44₅are arranged at a third level L3 below the second level L2 and which will be nearest the bottom face 28 of the plug housing 12 (FIGS. 17 and 22).

[0068] As noted above, channels 44₁, . . . , 44₈are arranged relative to one another to accommodate the eight conductors of an eight-conductor cable 8 in a specific sequence. That is, the cable 8 includes conductors or conductors designated 1-8 and the conductors are inserted into the channels 44₁, . . . , 44₈in the load bar housing 40, respectively. The channels 44₁, 44₂, 44₇and 44₈which are arranged at the longitudinally extending transverse edges of the load bar housing 40 thus receive the conductors designated 1, 2, 7 and 8, respectively. The passages 44₃and 44₆which are arranged immediately inward of passages 44₂and 44₇respectively, thus receive the conductors designated 3 and 6, respectively, and the passages 44₄and 44₅in the middle receive the conductors designated 4 and 5, respectively. As is known in the art, according to a standard terminating convention, conductors 4 and 5 operatively form conductor pair #1, conductors 1 and 2 form conductor pair #2, conductors 3 and 6 form conductor pair #3 and conductors 7 and 8 form conductor pair #4.

[0069] The arrangement of the channels 44₃,44₄,44₅,44₆in the two maximally spaced-apart levels L1,L3 is designed to reduce the crosstalk between the conductor pairs 1 and 3 during use of the plug 10. Specifically, it has been found that as the distance increases between the plane of conductors 4 and 5 of conductor pair #1 in the plug 10 and the plane containing conductors 3 and 6 of conductor pair #3, i.e., the distance between level L1 and level L3, crosstalk is reduced. Thus, since it is most desirable to reduce crosstalk between the conductor pairs #1 and #3, the level L1 of passages 44₃,44₆is maximally spaced from the level L3 of passages 44₄,44₅. In other words, as shown in FIGS. 3 and 4, the distance between the level L2 and each of levels L1 and L3 is less than the distance between the levels L1 and L3. It must be recognized that other combinations of two conductor pairs can be spaced apart from one another to provide a maximum separation by arranging the corresponding passages at the maximum separation from one another.

[0070] In view of the arrangement of the conductor-receiving passages 44 in three levels in the plug housing 12, the plug 10 includes three sizes of terminal blades 20 received in the terminal-receiving slots 16 (FIGS. 1 and 5). Terminal blades 20₃,20₆are the shortest and each is arranged in a respective one of the slots 16 communicating with passages 44₃,44₆, terminal blades 20₄,20₅are the longest and each is arranged in a respective one of the slots 16 communicating with passages 44₄,44₅, and terminal blades 20₁,20₂,20₇and 20₈have an intermediate length and each is arranged in a respective one of the slots 16 communicating with passages 44₁,44₂,44₇,44₈.

[0071] A plug and its components according to a second embodiment of the invention in which the conductor-receiving passages are arranged in two parallel rows or levels will now be described. In this connection reference is specially made to FIGS. 3a-5a, 10aand 12a-22a, (i.e., all figures designated with an “a” suffix) which specifically illustrate views of the second embodiment of the invention.

[0072] Initially, the plug housing is specially adapted to receive a load bar 18 which positions the conductors in two levels and in accordance with other aspects of the invention. Referring in particular to FIGS. 10aand 12a, the upper surface 32 in the forward portion 14cof the plug cavity is formed to cooperate with the two levels of conductor-receiving channels 44₁, . . . , 44₈in the load bar 18 to retain the conductors of the cable 8 therebetween. To this end, the upper surface 32 includes a plurality of arcuate portions 42_1-8the curvature of which is determined by the position of the conductor contacting the arcuate portion 42_1-8. Since the load bar assembly 18 is designed to retain the conductors of the cable 8 in two different planes (discussed in detail below), the arcuate portions 42_1-8of the upper surface 32 are designed similarly at two different spatial separations from the planar bottom face 30 of the cavity 14. In particular, arcuate portions 42₃and 42₆(those situated to overlie the conductors designated 3 and 6 of the cable) are situated at the largest distance from the bottom face 30 (D1 being the distance between the bottom face 32 and the farthest area of the arcuate portion therefrom), and arcuate portions 42₁, 42₂, 42₄, 42₅, 42₇and 42₈(those situated to overlie the conductors designated 1, 2, 4, 5, 7 and 8 of the cable) are situated at the shortest distance from the bottom face 30 designated D2. As a result of the different spacing of the arcuate portions 42_1-8from the bottom face 30, the depth of the terminal-receiving slots 16 varies with the deepest slots 16₁, 16₂, 16₄, 16₅, 16₇, and 16₈communicating with the arcuate portions 42₁, 42₂, 42₄, 42₅, 42₇and 42₈and the shallowest slots 16₃, 16₆communicating with the arcuate portions 42₃and 42₆(FIG. 12a). In the illustrated embodiment, the upper surface 32 is symmetrical about its center line C.

[0073] By means of such construction of the arcuate portions 42_1-8of the upper surface 32 of the forward portion 14cof the cavity 14 of the plug housing 12, and the construction of the load bar assembly 18 described below, the conductors of the cable 8 designated 3 and 6 will lie maximally spaced from the conductors designated 4 and 5 and as such, crosstalk between these conductor pairs is minimized.

[0074] The second embodiment of the load bar assembly 18 is shown in detail in FIGS. 13aand 14aand includes a load bar housing 40, a conductive strip 48 cover 48amade of an electrically conductive metallic material and a pair of conductive strips 50. Conductive strip cover 48ais elongated and is arranged in a longitudinal channel 52 defined in a center of the load bar housing 40 (FIG. 13a). Channel 52 has a width substantially the same as the width of conductive strip cover 48aand a depth greater than the thickness of conductive strip cover 48 in order to avoid projection of the conductive strip cover 48 above the top surface of the load bar housing 40. The depth of the channel 52 is preferably determined to ensure that the conductive strip cover 48awill be situated between channels 44₃and 44₆. The purpose of the interposition of a metallic element such as conductive strip cover 48abetween these channels, which will receive the conductors designated 3 and 6 forming a conductor pair is the same as in the first embodiment. Conductive strip cover 48amay be fixed in channel 52 or movably arranged therein. Referring to FIG. 15a, conductive strips 50, of which there are two, are substantially U-shaped and are arranged one on each side of the load bar housing 40. Conductive strips 50 thus have a flat portion 50aand projecting portions 50bextending from the transverse edges of the flat portion 50aand which are substantially parallel to one another. To accommodate conductive strips 50, two pair of parallel, longitudinally-extending grooves 54a,54bare formed in the lower surface 76 of the load bar housing 40 and receive the projecting portions 50bof the conductive strips 50 (FIG. 15a). Conductive strips 50 are thus situated adjacent the lower surfaces 58′,58″ of the load bar housing 40 and partially surround respective ones of the two pairs of channels 44₁,44₂,44₇, and 44₈which receive conductors 1, 2, 7 and 8, respectively, of the cable 8 terminated by the plug 10. The conductive strip 50 partly surrounding conductors 1,2 will operatively function to distribute crosstalk between the pair of conductors 1,2 and the other pairs of conductors and the conductive strip 50 partially surrounding conductors 7,8 will operatively function to distribute crosstalk between the pair of conductors 7,8 and the other pairs of conductors. Conductive strips 48,52 may be formed from foil and may be integrated into the load bar housing 40 or the plug housing 12.

[0075] The second embodiment of the load bar housing 40 is shown in FIGS. 15a-22aand is made of a dielectric material. Load bar housing 40 is elongate having a length approximately coextensive with cavity 14. Load bar housing 40 has a rearward portion 40aadapted to be received in the rearward portion 14aof the cavity 14 of the plug housing 12, an intermediate portion 40badapted to be received in the intermediate portion 14bof the cavity 14 and a forward portion 40cadapted to be received in the forward portion 14cof the cavity 14. Channel 52 is formed in the upper surface 56′ of the rearward body portion 40aand extends partially through the upper surface 56″ of the intermediate body portion 40b. Grooves 54a,54bare formed in the lower surfaces 58′,58″ also of the rearward and intermediate portions 40a,40bof the load bar housing 40 (FIG. 14a). Grooves 54acommunicate with the channels 44₃and 44₆(FIG. 22a). Grooves 54bextend to the rear edge of the load bar housing 40 (FIG. 14a). A step 60 (FIG. 13a) is formed between the forward and intermediate portions 40c, 40bwhich, upon insertion of load bar assembly 18 in the cavity 14, will abut against a shoulder 60adefined between intermediate and forward cavity portion 14band 14c(FIG. 11).

[0076] Load bar housing 40 further includes a “hinge” to enable rotational movement of the rearward portion 40arelative to the intermediate and forward portions 40b,40c. This movement may be realized once the load bar assembly 18 is inserted into the cavity 14 and the forward portion 40cof the load bar 40 is fixed within the forward portion 14cof the cavity 14. To this end, the load bar housing 40 includes a transverse slit 62 on the lower side. The presence of slit 62 allows the rearward portion 40aof the load bar housing 40 to flex with respect to the intermediate and forward portions 40b,40c. Also, the conductive strips 50 are provided with notches 50′ on each side in alignment with the slits 62 to reduce their rigidity and facilitate the flexure of the load bar housing 40 (FIG. 15a).

[0077] The channels 44₁, . . . , 44₈in the load bar housing 40 are constructed in a particular manner to position the conductors of the cable terminated by the plug 10 in two different planes. Channels 44₁, . . . , 44₈extend from one edge of the load bar housing 40 to the other edge. The channels 44₁, . . . , 44₈are numbered in sequence from left to right and the number corresponds to the designated number of the conductor of the cable 8 received in that channel. Channels 44₁and 44₂are situated alongside one another and formed by a shaped bore or cavity 64 (FIGS. 14aand 22a) in the load bar housing extending through the rearward portion 40aand intermediate portion 40b. In the forward portion 40c, the channels 44₁and 44₂are each defined by an arcuate indentation or trough 66 of the upper surface 56′″ of the load bar housing 40 (FIG. 21a). Channels 44₃and 44₆are each formed by a longitudinal indentation or trough 68 in the upper surface 56′ of the rearward portion 40aof the load bar housing 40 and which extends partially over the upper surface 56″ of the intermediate portion 40bof load bar housing 40, a shaped cavity or bore 70 in the load bar housing 40 extending through the remainder of the intermediate portion 40b, and an indentation or trough 72 in the upper surface 56′″ of the forward portion 40c(FIG. 13a). Channels 44₄and 44₅are situated alongside each other and are formed by a shaped cavity or bore 78 in the load bar housing extending through the rearward and intermediate load bar body portions 40a, 40band indentations 80 of the upper surface 56′″ of the forward portion 40c. Channels 44₇and 44₈are situated alongside one another and are formed by a shaped cavity or bore 82 in the load bar housing extending through the rearward and intermediate load bar body portions 40a, 40band indentations 84 of the upper surface 56′″ of the forward portion 40c.

[0078] Thus, channels 44₁, . . . , 44₈are arranged in three different, substantially parallel levels. Channels 44₃and 44₆are arranged at a first level L1 (the “level” being represented by a plane passing through the central axes of the channels 44) which will be nearest the top face 56 of the plug housing 12, channels 44₁, 44₂, 44₄, 44₅, 44₇and 44₈are arranged at second level L2 below the first level L1 nearest the bottom face 58 of the plug housing 12 (FIGS. 17aand 22a).

[0079] As noted above, channels 44₁, . . . , 44₈are arranged relative to one another to accommodate the eight conductors of an eight-conductor cable 8 in a specific sequence. That is, the cable 8 includes conductors or conductors designated 1-8 and the conductors are inserted into the channels 44₁, . . . , 44₈in the load bar housing 40, respectively. The channels 44₁, 44₂, 44₇and 44₈which are arranged at the longitudinally extending transverse edges of the load bar housing 40 thus receive the conductors designated 1, 2, 7 and 8, respectively. The passages 44₃and 44₆which are arranged immediately inward of passages 44₂and 44₇, respectively, thus receive the conductors designated 3 and 6, respectively, and the passages 44₄and 44₅in the middle receive the conductors designated 4 and 5, respectively. As in known in the art, according to a standard terminating convention, conductors 4 and 5 operatively form conductor pair #1, conductors 1 and 2 form conductor pair #2, conductors 3 and 6 form conductor pair #3 and conductors 7 and 8 form conductor pair #4.

[0080] In view of the arrangement of the conductor-receiving passages 44 in three levels in the plug housing 12, the plug 10 includes three sizes of terminal blades 20 received in the terminal-receiving slots 18 (FIGS. 1 and 5). Terminal blades 20₃,20₆are the shortest and each is arranged in a respective one of the slots 18 communicating with passages 44₃,44₆, terminal blades 20₄,20₅are the longest and each is arranged in a respective one of the slots 18 communicating with passages 44₄,44₅, and terminal blades 20₁,20₂,20₇and 20₈have an intermediate length and each is arranged in a respective one of the slots 18 communicating with passages 44₁,44₂,44₇,44₈.

[0081] By means of the load bar housing 14 in accordance with the invention, the entire portion of each of the conductors of the cable 8 within the plug housing 12 is positioned in a precise, pre-determined position, including at the location below the strain relief element 34. In this manner, a random arrangement of any portion of the conductors within the plug 10 is avoided. The position of the portion of each of the conductors which is to be engaged by the terminal blades 20 is also in a pre-determined position. Thus, in one preferred embodiment of a plug in accordance with the invention, the portion of each conductor between the location below the strain relief element 34 and the terminal blades 20 is fixed in position.

[0082] To terminate the cable 8 by means of the plug 10, a process described in U.S. patent application Ser. No. 09/246,165, filed Feb. 8, 1999 (incorporated by reference herein) may be used. In this process, two opposed longitudinal slits are made in the cable jacket to expose a length of the conductors at least as large as the length of the load bar housing 40. The conductors, which are usually in twisted pairs in the cable, are untwisted and pressed into the channels 44 in the load bar housing 40 in correspondence with the designation of the conductors, as in the conventional manner. The ends of the conductors extending beyond the load bar housing 40 are then cut flush with the front end of the load bar housing 40. The slit portions of the cable jacket are cut to extend only up to the slits 62. The conductive strips 48,50 may be arranged on the load bar housing 40 before or after the conductors of the cable are threaded into the load bar housing 40. In the alternative, conductive strips 48,50 may be incorporated into the load bar housing during the fabrication thereof. The load bar assembly 18 having the slit portions of the cable jacket alongside it is then inserted into the cavity 14 in the plug housing 12 until the step 60 abuts against the shoulder 60ain cavity 14. In this manner, the rearward portion 40aof the load bar housing 40 will be situated in the rearward portion 14aof the cavity 14, the intermediate portion 40bwill be situated in intermediate portion 14band the forward portion 40cwill be situated in forward portion 14c. Since the cavity 14 is dimensioned to receive the load bar assembly 18 without clearance below the load bar assembly 18, and with some clearance above the load bar assembly 18, upon insertion of the load bar assembly 18 into the cavity 14, the slit portion of the cable jacket below the load bar assembly 18 causes an upward flex of the rearward portion 40aof the load bar housing 40, which flexure is enabled by the slits 62.

[0083] The terminal blades 20 in the terminal-receiving slots 16 in the plug housing 12 are then pressed into the conductors to pierce the insulation thereof and engage the metal cores therein. The terminal blades 20 may be pre-positioned in the slots 16 so that it is only necessary to press them into the conductors.

[0084] Simultaneously with the pressing of the terminal blades 20 into the conductors or thereafter, the strain relief element 34 is pressed inward or set to engage the slit portion of the cable jacket overlying the rearward portion of the load bar assembly 18 to thereby secure the cable 8 in connection with the plug 10. The pressing of the strain relief element 34 inward causes the rearward portion 40aof the load bar housing 40 to be pressed downward against the bottom surface of the cavity 14 thereby reducing the angle between the rearward portion 40aand intermediate portion 40bof the load bar housing 40. The rearward portion 40awill not be co-planar with the intermediate portion 40bin view of the presence of the cable jacket between the rearward portion 40aand the lower surface of the cavity 14.

[0085] It has been found that the positioning of the conductors in pre-determined positions below the strain relief element 34 provides consistent NEXT values between plugs having the same construction. By contrast, in conventional plugs in which the conductors are randomly arranged at the location below the strain relief element, when the strain relief element is pressed inward into the cable, the conductors in the cable remain in this random arrangement and even more so, the conductors are susceptible to additional random movement. This random arrangement of conductors results in inconsistent NEXT values for plugs having the same design.

[0086] A particular advantage of the construction of the plug housing 12 and load bar assembly 18 in accordance with the invention is that cables having different thicknesses of jackets and different diameter conductors can be terminated by the plug 10. For the conductors, the channels 44 are provided with a size equal to or larger than a relatively large diameter conductor so that smaller diameter conductors can also be positioned therein. For the different thicknesses of jackets, the height of the rearward portion 14aof the cavity 14 is provided with a size greater than the height of the load bar assembly 18 and twice the thickness of the jacket of a relatively large cable. As such, cables with smaller cable jackets and insulation sheaths can be used to surround the load bar whereby the strain relief element 34 would engage with the upper portion of the cable jacket and thereby fix the cable in connection with the plug 10.

[0087] The plug 10 described above may be used to terminate an end of a multi-conductor cable 8 (FIG. 1) whereby the other end of the cable is terminated by a similar plug or another modular connector and is left unterminated. A plug-cable assembly is thus formed.

[0088] Although the load bar housing 40 and plug housing 12 are designed to receive and terminate eight conductors, other load bars having a different number of channels 44 and plug housings having a corresponding number of terminal-receiving slots 16 could also be used applying the principles of the invention as described above.

[0089] Instead of providing two or three different substantially parallel levels of channels 44 in the load bar housing 40, a load bar housing in accordance with the invention may be constructed with more than three parallel levels of channels. That is, aside from providing in the load bar housing 40 the preferred maximal spacing between the channels receivable of the conductors designated 3 and 6 and the channels receivable of the conductors designated 4 and 5, the position of the remaining channels receivable of the conductors designated 1, 2, 7 and 8 is not required to be as shown in the illustrated embodiment, i.e., in a common level. For example, the channels receivable of conductors 1,2 may be at a different level than the channels receivable of conductors 7,8. Moreover, each channel receivable of conductors 1, 2, 7 and 8 may be at its own level, i.e., not defining a plane with another channel which is parallel to the plane in which the channels receivable of, e.g., conductors 3,6 are situated. In any of these proposed modifications, the terminal-receiving slots 16 and terminal blades would be dimensioned accordingly.

[0090] In another proposed modification of the plug described above, the cavity 14 does not extend to a location below the terminal-receiving slots 16. Thus, the cavity 14 includes only the rear portion 14aand the intermediate portion 14band not the forward portion 14c. The load bar housing 40 is similarly formed to include only the rearward portion 40aand the intermediate portion 40band not the forward portion 40c. In this case, the plug housing 12 is formed to include channels in alignment with the channels 44 in the load bar housing 40 and in communication with the terminal-receiving slots 16. During the assembly of the plug, the conductors would be cut flush with the front end of the load bar housing 40 and then pushed or threaded forwardly to extend beyond the front end of the load bar housing 40 a distance approximately equal to the length of the channels in the plug housing.

[0091] The use of the load bar housing 40 and load bar assembly 18 described above is not limited to the plug housing 12 described above and may be used in combination with other plug housings. The load bar housing 40 may also be used without the conductive strips 48,50, possibly with other means to ensure compliance with industry standards for electrical performance, in which case, the load bar housing 40 could be formed without the channel 52 and grooves 54a,54b. The other features of the load bar housing 40 would still be present.

[0092] Further, it is not required that the load bar assembly includes all three conductive strips 48,50. Rather, the load bar assembly 18 may include for example, only conductive strip 48 or only conductive strips 50.

[0093] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. Accordingly, it is understood that other embodiments of the invention are possible in the light of the above teachings.