Three row plug and receptacle connectors with ground shield

Field of the Invention

0001The present invention relates to electrical connectors, and more particularly, to plug and receptacle connectors wherein the plug and receptacle are provided with multiple layers of contact elements and each layer is electrically isolated from other layers.

Background of the Invention

0002The continued development of sophisticated electronic devices for data processing and communications systems is placing rigorous demands on electrical connectors. Increasing integration of solid state devices, combined with the need to increase the speed of data processing and communication systems, requires that connectors have higher densities, higher pin counts, and better electrical performance than in the past.

0003Density and pin count are often viewed interchangeably, but there are important differences. Density refers to the number of contacts provided per unit length. In contrast, the number of contact elements that can reasonably withstand the mating and unmating forces is referred to as the pin count.

0004As more functions become integrated on semiconductor chips or on flexible circuit substrates and more chips are provided on printed circuit boards (PCBs), each PCB or flexible circuit must provide more inputs and outputs (I/Os). The demand for more I/Os directly translates to a demand for greater density. In addition, many system components are capable of operation at faster speeds than previously. Faster speed can result in the generation of potentially interfering signals, i.e., crosstalk and noise. The connectors used in such high-speed board-to-board, board-to-cable and cable-to-cable communications may be treated for design purposes like transmission lines in which crosstalk and noise become significant concerns. Indeed, the electrical performance of high-speed board-to-board, board-to-cable and cable-to-cable communications is dependent upon the amount of crosstalk and noise introduced at the connector interface. As density increases, the potential for crosstalk and noise at the connector interface also increases.

0005Density, contact element count, and electrical performance are related to one another. Design factors should be balanced to optimize the connector in terms of its density, contact element count and electrical performance. Density can be increased by decreasing the distance between contact elements and by increasing the number of rows in a connector. Increasing the density may also increase the contact element count because 1) more contact elements are available for mating and unmating, and 2) higher density reduces the linear tolerances per contact element as mating and unmating forces are averaged over more contact elements. An increase in contact element density may, however, adversely affect the electrical performance of the connector since crosstalk can increase by bringing the contact elements into closer proximity to one another. The contact element count is limited in part by the mechanical forces applied when the connector is mated and unmated.

0006As was recognized in <patcit id="pcit0001" dnum="US4824383A"><text>U.S. Patent No. 4,824,383 - Lemke</text></patcit>, incorporated herein by reference, an important connector design consideration is the provision of an electrical connection while avoiding degradation of component performance. Prior to this patent, connector designs had been proposed in which a ground plane and alternating ground contacts together with shielding extensions were introduced to minimize electrical discontinuities, i.e., crosstalk and noise. While performance was controlled in such prior devices, density was limited.

0007<patcit id="pcit0002" dnum="US4824383A"><text>U.S. Patent No. 4,824,383</text></patcit> proposed designs for plug and receptacle connectors for multiple conductor cables or multiple trace substrates. In such designs individual contact elements or groups of contact elements were electrically isolated to prevent or minimize crosstalk and signal degradation. In the individually isolated design, a conductive base plate was provided with a number of walls arranged in side-by-side relationship, thereby defining a number of channels. A contact support member formed from electrical insulating material was designed to have a number of fingers, wherein a finger was positioned within each channel. Each finger of the contact support member supported an individual contact element. In the group isolated design, the base plate and walls defined channels for isolating sets of contact elements. Each set was carried by an enlarged finger of the contact support member. In this embodiment the base plate and walls were said to provide a ground plane to each contact element group, resulting in impedance control and lowered cross-talk. Both the individually isolated design and the group isolated design included a cover or shell formed from a conductive material, thereby providing additional isolation.

0008Although, the connectors disclosed in <patcit id="pcit0003" dnum="US4824383A"><text>U.S. Patent No. 4,824,383</text></patcit> increased contact element density, industry driven density demands continued to grow. In relation to meeting such demands, it was believed advantageous to provide an interconnection between the ground structure of the plug and receptacle connectors, to provide a structure to the receptacle that eliminated loose fits between the receptacle and contact element carrier and to provide a plug and receptacle whose interengaged signal contacts were disposed more closely to electrical ground. <patcit id="pcit0004" dnum="US5057028A"><text>U.S. Patent Nos. 5,057,028 - Lemke et al.</text></patcit> and <patcit id="pcit0005" dnum="US5169324A"><text>5,169,324 - Lemke et al</text></patcit>. (now <patcit id="pcit0006" dnum="USRE35508E"><text>U.S. Patent No. Re. 35.508</text></patcit>), all incorporated herein by reference, proposed designs to meet those objectives. In those patents, two row plug and receptacle connectors are described for attachment to printed circuit boards (PCBs), so that when such connectors are mated the PCBs are electrically interconnected.

0009The plug is described as preferably including a die-cast, metallic frame member connectable to an electrical potential having a top and a bottom wall connected at opposite ends by uprights. An intermediate wall extends between the uprights in a plane generally parallel to the walls The frame thereby defines channels, namely upper and lower channels. The upper and lower channels are each described as being further divided by a central wall. Contact elements are embedded in extended fingers of insulating material. The extended fingers are inserted into each channel against the central plate and oriented such that the planar portion of each contact element is exposed. The contact elements thereby form two rows facing away from the central plate towards the walls. Tail portions of the contact elements extend rearwardly through partitions formed of insulating material for attachment to a PCB.

0010The receptacle is described as including a die-cast, metallic frame having an open front and rear. The frame includes upper and lower crossbars which are interconnected at corresponding ends by uprights. A central plate extends across the frame between the uprights in a generally planar relationship to the crossbars. The frame thereby defines two channels, namely upper and lower channels. The upper and lower channels are in turn divided at the midpoint by a further upright, thereby defining four sub-channels. A pair of insulating nosepieces are mounted to the front of the frame. A contact block, formed from insulating material, is designed to fit within each subchannel. Curve shaped, electrical contact springs are imbedded into each contact block. The number and design of the contact springs corresponds to the number and design of the contact elements in the plug. When a contact block is fitted into the receptacle frame, the curved contact end of each contact spring is positioned within a window formed in the nosepiece. Each window is designed to receive and support the curved forward end of the contact spring. The contact springs thereby form two rows wherein the curved portion of each contact spring faces away from the crossbars towards the central plate. The tail portions of the contact springs extend rearwardly from the contact block for attachment to a PCB.

0011As the plug and receptacle components are brought together, they are guided into aligned engagement by cooperative interaction between tapered ends, the central wall and guide slots. Such interaction serves to accurately align the contact elements in the plug with the contact springs in the receptacle. From <patcit id="pcit0007" dnum="US5057028A"><text>US-A-5,057,028</text></patcit> is known a plug and receptacle according to the preamble of the independent claims. <patcit id="pcit0008" dnum="US5507655A"><text>US 5,507,655</text></patcit> shows a plug and receptacle comprising three rows of contact elements. However, this prior art belongs to a another type of electrical connector.

0012While the connectors described above serve to satisfy certain density needs in the industry, industry driven density demands still continue to grow. Therefore, it is the technical problem of the invention to provide higher density plugs and receptacles which are capable of transmitting high frequency signals without degradation.

0013In meeting this continuing need, the present invention not only includes a novel connector structure that provides for increased contact element density, but also, permits connectors of this type to interconnect two PCBs in generally the same plane. In achieving this latter feature, the plug and receptacle of the connector are designed for right angle mounting, i.e., the front of the plug or receptacle is oriented in a plane at substantially a right angle to the PCB on which the plug or receptacle is mounted. Examples of right angle connectors have been proposed in the past, for example the connectors disclosed in <patcit id="pcit0009" dnum="US5399105A"><text>U.S. Patent Nos. 5,399,105 - Kaufman et al.</text></patcit>, <patcit id="pcit0010" dnum="US5169343A"><text>5,169,343 - Andrews</text></patcit>, and <patcit id="pcit0011" dnum="USRE32691E"><text>Re. 32,691 - Dola et al</text></patcit>. However, none of those connectors are designed for nor concerned with high density contact elements. Thererby, <patcit id="pcit0012" dnum="US5399105A"><text>US 5,399,105</text></patcit> is not related to an electrical connector system comprising a plug and a receptacle. <patcit id="pcit0013" dnum="US5399105A"><text>US 5,399,105</text></patcit> includes two memory card connectors in vertically stacked relationship and a conductive shroud without any intermediate wall or center wall.

Summary of the Invention

0014The above described problems are resolved and other advantages are achieved in an electrical plug and receptacle according to claim 1 and 8 for terminating multiple electrical conductors. The plug includes a frame having a top wall, a bottom wall, first and second intermediate walls, a center wall and end walls. The end walls maintain the top, bottom, and intermediate walls in spaced relationship. This arrangement of walls defines first, second and third channels. First, second and third insulated support structures are provided, which have forwardly extending fingers. Each of the fingers is received in one of the first, second or third channels. A plurality of contact elements are disposed on each of the fingers, thereby defining a row. Each of the contact elements is connectable to one of the conductors. With this structure, the plug provides first second and third rows of contact elements. The frame is connectable to an electrical potential.

0015It is preferred for the plug walls to be integrally formed and for the frame to be formed from a single metallic casting.

0016The plug also can include an extension member, located proximate the first and second intermediate walls, for electrically extending the isolation provided by such walls to the tails of the contact elements. The extension member includes first and second side walls and end walls, wherein one edge of each of the first and second side walls is positioned proximate the first and second intermediate walls. It is also preferred to provide a tail guide formed from insulating material. A plurality of bores formed in the tail guide serve to arrange the tails of the contact elements in a pattern.

0017The contact elements include a wiper portion and a tail portion defining an angle therebetween. In certain embodiments, the contact elements include a bend so that the wiper and tail portions are at an angle of less than 180 degrees to one another, and, in one embodiment, approximately 90 degrees. If regarded in the opposite sense of rotation this angle can also be defined as being greater than 180°, in particular approxim. 270°.

0018The receptacle includes a frame formed from a base plate, first and second walls, mounted to the base plate and extending toward the front of the receptacle, and third and fourth walls mounted to the base plate and extending toward the rear of the receptacle. The base plate has a number of passages therethrough, wherein the passages are located on both sides of the first wall. A plurality of insulated support structures adapted to receive a plurality of contact springs therein are positioned in the passages. A plurality of contact springs are disposed in each of the support structures. Each contact spring is connectable to one of the conductors. When the support structures are positioned in the passages, the receptacle provides first second and third rows of contact springs.

0019It is preferred for the receptacle walls to be integrally formed and for the frame to be formed from a single metallic casting.

0020The receptacle also can include an extension member, located proximate the third and fourth walls, for electrically extending the isolation provided by such walls to the tails of the contact elements. The extension member includes a second base plate having walls formed thereon. Each of the walls is positioned proximate the third and fourth walls. It is also preferred to provide a tail guide formed from insulating material. A plurality of bores formed in the tail guide serve to arrange the tails of the contact elements in a pattern.

0021The contact springs include a wiper portion and a tail portion defining an angle therebetween. In certain embodiments, the contact elements include a bend so that the wiper and tail portions are at an angle greater than 180 degrees to one another, and, in one embodiment, approximately 270 degrees.

0022An electrical connector system is shown to include a first connector having three arrays of contact elements and first and second conductive walls separating the three arrays of contact elements and a second connector having three arrays of contact elements and third and fourth conductive walls separating the three arrays of contact elements. The second connector is adapted to mate with the first connector so that the contact elements of the first and second connectors form electrical connections therebetween and so that the conductive walls are brought to within a predetermined distance from each other thereby reducing crosstalk between adjacent arrays of contact elements.

Brief Description of the Drawings

0023The present invention will be better understood and its numerous objects and advantages will become apparent by reference to the following detailed description of the invention when taken in conjunction with the following drawings, in which: <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> is a perspective view generally depicting a plug and a receptacle constructed in accordance with the present invention;</li><li><figref idref="f0002">Figure 2</figref> is a front elevational assembly view of the plug of the plug depicted in <figref idref="f0001">Fig. 1</figref>;</li><li><figref idref="f0002">Figure 3</figref> is a sectional view of only the frame of the plug depicted in <figref idref="f0002">Fig. 2</figref> taken along the line 3-3;</li><li><figref idref="f0002">Figure 4</figref> is a sectional taken along the line 4-4 in <figref idref="f0002">Fig. 2</figref>;</li><li><figref idref="f0002">Figure 5</figref> is a bottom view of the plug depicted in <figref idref="f0002">Fig. 2</figref>;</li><li><figref idref="f0003">Figure 6</figref> is a front elevational assembly view of the receptacle depicted in <figref idref="f0001">Fig. 1</figref>;</li><li><figref idref="f0003">Figure 7</figref> is a sectional taken along the line 7-7 in <figref idref="f0003">Fig. 6</figref>;</li><li><figref idref="f0004">Figure 8</figref> shows an alternative embodiment of the receptacle depicted in <figref idref="f0003">Fig. 7</figref>;</li><li><figref idref="f0003">Figure 9</figref> is a bottom view of the receptacle depicted in <figref idref="f0004">Fig. 8</figref>; and</li><li><figref idref="f0004">Figure 10</figref> is a section view of the receptacle depicted in <figref idref="f0004">Fig. 8</figref> into which the plug of <figref idref="f0002">Fig. 4</figref> has been inserted.</li></ul>

Detailed Description of the Invention

0024An electrical connector system constructed in accordance with the present invention is generally shown in <figref idref="f0001">Figure 1</figref>. The connector system is seen to include two major components. A plug 10 and a receptacle 12. It is noted that plug 10 and receptacle 12 will find particular use as terminators for terminating components containing multiple electrical conductors, i.e. cables or traces on circuit boards. Due to the relatively large number of electrical conductors now forming transmission cables, such conductors are typically splayed and connected to a printed circuit board (PCB). By attaching plug 10 and receptacle 12 to PCBs 14 and 16 the contact elements mounted in such devices are capable of being connected to one or more of the multiple conductors. Because splaying and connection of multiple conductors to a PCB is known and does not form a part of the present invention, it is not described in any greater detail herein.

0025Considering first plug 10, it is seen to include several major components. A frame 18 includes a first crossbar or top wall 20, a second crossbar or bottom wall 22. a first intermediate wall 24, a second intermediate wall 26 (shown in <figref idref="f0002">Figures 3 and 4</figref>) and end walls 28 and 30. End walls 28 and 30 serve to maintain walls 20, 22, 24 and 26 in spaced relationship to one another. This arrangement of walls defines a number of channels which will be described in greater detail in relation to <figref idref="f0002">Figure 2</figref>. In the preferred embodiment, the walls of frame 18 are integrally formed. It is especially preferred to form such walls as a single metallic casting.

0026Plug 10 also includes a number of insulated support structures. Only one support structure 32 is shown in <figref idref="f0001">Figure 1</figref>. Support structure 32 includes a forwardly extending finger 34. A plurality of contact elements 36 are disposed on finger 34 thereby defining a row of contact elements. As will be described below, each contact element includes a tail which extends rearwardly from frame 18 and is connected to PCB 14. Thus, each contact element 36 is connectable to one of the electrical conductors. Plug 10 is also shown to include plates 38 and 39, the purpose of which will be explained in greater detail below.

0027Consider now receptacle 12 shown in <figref idref="f0001">Figure 1</figref>. Similar to plug 10, receptacle 12 includes a frame 40. Frame 40 is formed from base plate 42 and walls 44 and 46. Walls 44 and 46 are mounted to the base plate and extend towards the front of receptacle 12. Additional walls 48 and 50, shown more clearly in <figref idref="f0003">Figure 7</figref>, are also attached to base plate 42, however, these walls extend toward the rear of receptacle 12. As will be described in greater detail in relation to <figref idref="f0003 f0004">Figures 6 through 8</figref>, base plate 42 includes a number of passages, wherein such passages are located on both sides of wall 44 and on only one side of wall 46.

0028Similar to plug 10, receptacle 12 also includes a plurality of insulated support structures. Only structures 52, 54, 56, and 58 are shown. Each of these support structures is adapted to receive a plurality of contact springs, wherein the array of contact springs disposed within a support structure define a row of contact springs. As will be discussed in greater detail below, the contact springs extend rearwardly through base plate 42 for attachment to PCB 16. In this manner, each contact spring is connectable to one of the conductors for which receptacle 12 is serving as a terminator.

0029Similar to plug 10, it is preferred for walls 44, 46 and base plate 42 to be integrally formed. It is especially preferred for frame 40 to be formed as a single piece of metallic casting. In the embodiment shown in <figref idref="f0001">Figure 1</figref>, frame 40 also includes wall 62. It will be appreciated that high density connectors such as plug 10 and receptacle 12 will require alignment so that each contact element 36 will wipe against and make electrical contact with a single contact spring 60. To this end, various alignment structures are provided. For example, frame 18 includes cylindrical bores 64 and 66. When plug 10 is inserted into receptacle 12, bore 64 slides on post 68 and bore 66 slides on post 70. In this manner, gross alignment is provided. <figref idref="f0001">Figure 1</figref> also discloses slots 72 and 74 formed in end wall 30 and slots 76 and 78 formed in end wall 28. As plug 10 is inserted into receptacle 12, the ends of wall 44 slide within slots 72 and 76 while the ends of wall 46 slide within slots 74 and 78. In this manner, further alignment is provided.

0030Still further alignment is provided by the sliding contact between the inside surface of wall 62 and the outside surface of wall 20 and the inside surface of walls 38 and 39 and the outside surface of wall 46. Additional alignment is provided by the center portion 80 of wall 46 passing in the gap 82 between walls 38 and 39. Additional alignment for plug 10 and receptacle 12 is described below. However, by means of the previously and below described alignment mechanisms, independent electrical connection is established between a single contact element and a single contact spring.

0031Referring now to <figref idref="f0002">Figures 2-4</figref>, plug 10 will be described in greater detail. As described previously, frame 18 includes a number of passages 84, 86, 88, 90, 92 and 94. Insulated support structure 32, previously shown in <figref idref="f0001">Figure 1</figref>, is positioned within passage 90. The other insulated support structures are positioned as follows: structure 98 is in passage 86; structure 96 is in passage 84; structure 100 is in passage 88; structure 102 is in passage 94; and structure 104 is in passage 92. It will be appreciated from <figref idref="f0002">Figure 2</figref>, and also from <figref idref="f0002">Figure 4</figref>, that support structures 96 and 98 are oriented within their respective passages, so that the wiper or forward portion of contact elements 36 face away from and are insulated from wall 20. Similarly support structures 102 and 104 are oriented within passages 94 and 92 so that the wiper portion of contact element 36 faces away from wall 22 and towards wall 38. Finally, support structures 32 and 100, positioned within passages 90 and 88, respectively, are oriented such that the wiper portion of contact element 36 faces away from wall 22 towards wall 20. It is noted at this point, and as can be seen in reference to <figref idref="f0001">Figure 1</figref>, that insulated support structures 32 and 100 are integrally formed, being joined by a small web portion 106. Support structures 96 and 98 are integrally joined in a similar manner as are support structures 102 and 104. In an especially preferred embodiment of plug 10, in order to assure precise orientation of support structures and corresponding contact elements, the ends of the support structures slide within guide slots 108 formed in end walls 28 and 30. Additionally, slot 110, formed by joining two support structures with web portion 106 (shown in <figref idref="f0001">Figure 1</figref>) receives center wall 112, shown in <figref idref="f0002">Figure 3</figref>.

0032Referring specifically to <figref idref="f0002">Figure 3</figref>, center wall 112 is shown to include a number of posts 114, 116 and 118. As will be described in relation to <figref idref="f0003">Figure 6</figref>, when plug 10 and receptacle 12 are joined, posts 114-118 serve to provide further alignment and serve to provide additional electrical isolation between groups of contact elements.

0033Referring now specifically to <figref idref="f0002">Figure 4</figref>, it will be seen that each contact element 36 is provided with a tail for mounting to a PCB (not shown). As will be appreciated from viewing <figref idref="f0002">Figures 2 and 4</figref>, three rows of contact elements are provided by plug 10. The first row of contact elements consists of those arrays of contact elements mounted to support structures 96 and 98. The second row of contact elements consists of those arrays of contact elements mounted to support structures 32 and 100 and the third row of contact elements are those elements mounted to support structures 102 and 104. One of the features of the present invention is that each row of contact elements is electrically isolated from other rows of contact elements when frame 18 is connected to an electrical potential, preferably ground potential. This electrical isolation feature occurs for both the forward or wiper part of the contact element as well as the tail of the contact element. Referring to the tail portion of the contact element, it will be seen from <figref idref="f0002">Figure 4</figref> that intermediate walls 24 and 26 extend rearwardly from frame 18 thereby electrically isolating a portion of the tails contained in the three rows of contact elements. In order to complete the electrical isolation of the rows of contact elements, an additional isolating member 120 is provided.

0034Referring to <figref idref="f0002">Figures 4 and 5</figref>, member or frame 120 is shown to include walls 122 and 124 which are maintained in spaced relation to each other by end walls 126 and 128. When positioned as shown in the Figures, frame 120 serves to extend the electrical isolation between the tail portions of the contact element rows from the ends of walls 24 and 26 to the point at which the tails are mounted to a PCB. It is preferred for frame 120 to be integrally formed as a single metallic casting.

0035As shown in <figref idref="f0002">Figure 4</figref>, the tail portions of contact elements 36 are bent at a right angle. For purposes of explanation, plug 10 can be considered as having an insertion direction and a mounting direction. The insertion direction is that direction which plug 10 moves in order to be inserted into receptacle 12, i.e. a direction from frame 18 toward the front of plug 10. The mounting direction is that direction which permits plug 10 to be mounted to a printed circuit board, i.e. that direction which parallels the bores in the PCB in which the tails are to be mounted. As shown in <figref idref="f0002">Figure 4</figref>, an angle of less than 180° exists between the insertion direction and the mounting direction. Preferably this angle is approximately 90°. In this regard, plug 10 is a right angle plug.

0036In order to assure that the tails of contact elements 36 are arranged in a pattern which will match the pattern of bores contained on the PCB, a tail guide 130 is provided. Guide 130 is preferably formed from insulating material and has a plurality of bores passing there through. As will be seen in <figref idref="f0002">Figures 4 and 5</figref>, each tail portion of a contact element 36 passes through an individual bore in guide 130. In order to insure proper positioning of guide 130 in frame 18, key dimples 132 are provided. Key dimples 132 are designed to fit within appropriate recesses formed in frame 18. As shown in <figref idref="f0002">Figure 4</figref>, guide 130 includes a pair of channels through which walls 122 and 124 of member 120 extend. Thus, electrical isolation is further provided to the tails of contact elements 36 as they pass through guide 130.

0037Finally, mounting bores 134 are provided in frame 18 for the mounting of assembled plug 10 to PCB 14.

0038Referring now to <figref idref="f0003">Figure 6</figref>, receptacle 12 will be described in greater detail. It will be recalled from Figure that receptacle 12 includes a frame 40 having a base plate 42. A first wall 44 and a second wall 46 are attached to baseplate 42 and extend forward towards the front of receptacle 12. As shown in <figref idref="f0003">Figure 6 and Figure 7</figref>, wall 44 includes several components, namely cap 140 and 142, support wall 144, end portions 146 and 148 and central portion 150. Preferably, the components of wall 44 are integrally formed as a part of the single piece, metallic receptacle casting referenced previously. Similarly, wall 46 includes cap members 152 and 154, support wall 156, center alignment post 80 and angle ends 158 and 160. As described previously, when plug 10 and receptacle 12 are joined, end members 146 and 148 will slide within slots 72 and 76 of plug 10, while angled ends 158 and 160 will move within slots 74 and 78 of plug 10.

0039As will be appreciated from <figref idref="f0003">Figure 7</figref>, frame 40 has several passages formed therein. In particular, a passage is formed between wall 62 and support wall 144. A second passage is formed between support wall 144 and a wall 162. A third passage is formed between wall 162 and wall 156. It is noted that these passages extend across base plate 42. As shown in <figref idref="f0003">Figure 6</figref>, these passages are essentially divided in half by central portion 150. As was noted in connection with <figref idref="f0001">Figure 1</figref>, a number of insulated support structures (52, 54, 56, and 58) are inserted into these passages. As will be seen in <figref idref="f0003">Figure 7</figref>, the insulated support structures also include several components.

0040As shown in <figref idref="f0003">Figure 7</figref>, the insulated support structures include a base member 164 from which extend fingers 166. Base members 164 and fingers 166 are adapted to receive a plurality of contact springs 60. To this end a portion of contact spring 60 is embedded in base member 164. The forward end of the contact spring extends forward from base member 164 and is captured in the end portion of finger 166. It is noted that the end of spring number 60 is free to move within a pocket formed at the end of finger 166. Each contact spring 60 is also provided with a tail which extends rearwardly from base member 164.

0041As explained above, one of the features of the present invention, is that the contact springs are arranged in rows and that such rows are electrically isolated from one another. As shown in <figref idref="f0003">Figure 7</figref>, three rows of contact springs are provided, wherein one row is provided on one side of support wall 144 and oriented so that the curved end or spring portion of the contact spring faces wall 62. Another row of contact springs is provided on the other side of support wall 144 and oriented so that the spring portion faces wall 46. A third row of contact springs is provided adjacent support wall 156 and oriented so that the spring element is facing towards support wall 144. Support wall 144 and wall 162 serve to electrically isolate the contact springs when frame 40 is connected to an electrical potential, preferably ground potential. In order to electrically isolate the tail portions of contact spring 60, an isolation extension frame 167 or second base plate, respectively is provided. As shown in <figref idref="f0003">Figure 7</figref>, frame 167 includes a third wall 168 and a fourth wall 170. In order to maintain electrical isolation, one edge of walls 168 and 170 is positioned proximate or in contact with the end of wall 144 and 162. Walls 168 and 170 can thus be considered as extending the isolation of walls 144 and 162. In an especially preferred embodiment, frame 167 is integrally formed as a metallic casting.

0042Referring now to <figref idref="f0004">Figure 8</figref>, an alternative embodiment of receptacle 12 is depicted. As shown in <figref idref="f0004">Figure 8</figref>, the tail portions of contact spring 60 are bent at a right angle. Similar to plug 10, for purposes of explanation, receptacle 12 can be considered as having an insertion direction and a mounting direction. The insertion direction is that direction in which receptacle 12 receives plug 10, i.e., a direction from the front of receptacle 12 toward base plate 42. The mounting direction is that direction which permits receptacle 10 to be mounted to a printed circuit board, i.e. that direction which parallels the bores in the PCB in which the tails are to be mounted. As shown in <figref idref="f0003">Figure 7</figref>, an angle approximately equal to 180° exists between the insertion direction and the mounting direction while in <figref idref="f0004">Figure 8</figref>, an angle less than 180° exists between the insertion direction and the mounting direction. For the receptacle shown in <figref idref="f0004">Figure 8</figref>, preferably this angle is approximately 90°. In this regard, the receptacle shown in <figref idref="f0004">Figure 8</figref>, is a right angle receptacle.

0043In order to maintain electrical isolation between the tails of the rows of contact springs depicted in <figref idref="f0004">Figure 8</figref>, support wall 172 and wall 174 extend rearwardly from base plate 42 between the tails of the contact springs. Walls 172 and 174 generally correspond to support wall 144 and wall 162 shown in <figref idref="f0003">Figure 7</figref>. In order to maintain the electrical isolation beyond the bend portion of the tail elements, an isolation extension frame 175 is provided. Frame 175 includes walls 176 and 178 which are maintained in spaced relationship by end walls 180 and 182 (shown in <figref idref="f0003">Figure 9</figref>). It is especially preferred for extension member 175 to be integrally formed as a single metallic casting, similar to member 120 described in relation to <figref idref="f0002">Figures 4 and 5</figref>. Similarly, it is especially preferred for walls 168 and 170, shown in <figref idref="f0003">Figure 7</figref>, to form a part of a single extension member.

0044Referring now specifically to <figref idref="f0003">Figure 9</figref>, a bottom view of the embodiment shown in <figref idref="f0004">Figure 8</figref> is depicted. As shown in <figref idref="f0003">Figure 9</figref>, wall 183 includes support walls 184 and 186. Wall 184 generally corresponds to wall 156 shown in <figref idref="f0003">Figure 7</figref>. Although not shown in <figref idref="f0003">Figure 7</figref>, a support wall corresponding to wall 186 is included in the embodiment of receptacle 12 shown in that Figure.

0045In order to assure that the tails of contact spring 60 are arranged in a pattern which will match the pattern of bores on a PCB, a tail guide 190 is provided. Guide 190 is preferably formed from insulating material and has plurality of bores arranged in a particular pattern passing there through. As will be seen in <figref idref="f0004">Figures 8</figref> and <figref idref="f0003">9</figref>, each tail portion of a contact spring 60 passes through a individual bore in guide 190. In order to insure proper positioning of guide 190 in base plate 42, key dimples 192 are provided. Dimples 192 are designed to fit within appropriate recesses formed in frame 40. Similar to guide 130, guide 190 includes a pair of channels through which walls 176 and 178 pass. Thus electrical isolation is provided to the tails of contact spring 60 as they pass through guide 190.

0046Referring now to <figref idref="f0004">Figure 10</figref>, an electrical connector system 200 is shown to include a plug portion 210 and a receptacle portion 212. Plug portion 210 corresponds to plug 10 shown in <figref idref="f0002">Figure 4</figref> and receptacle portion 212 corresponds to the embodiment of receptacle 12 shown in <figref idref="f0004">Figure 8</figref>. As shown in <figref idref="f0004">Figure 10</figref>, plug 210 includes three arrays of contact elements 214, 216 and 218. Plug 210 is also shown to include conductive walls 220 and 222. Receptacle 212 is shown to include three arrays of contact springs 224, 226 and 228. Receptacle 212 is also shown to include conductive walls 230 and 232 which separate the three arrays of contact springs. Plug 210 and receptacle 212 are adapted to mate with each other so that the arrays of contact elements 214, 216 and 218 form electrical connections with the arrays of contact springs 224, 226 and 228. Moreover, when mated, conductive walls 220, 232, 222 and 230 are sandwiched with contact elements and contact springs disposed therebetween, thereby reducing crosstalk between adjacent arrays. It will also be seen that conductive wall 232 extends to within a closer predetermined distance with conductive wall 234. A similar arrangement exists between conductive wall 222 and wall 236. The close proximity of the ends of these walls to one another forms a so-called "choke" joint, explained in greater detail in <patcit id="pcit0014" dnum="US5057028A"><text>U.S. Patent Nos. 5,057,028</text></patcit> and <patcit id="pcit0015" dnum="US5169324A"><text>5,169,324</text></patcit> (<patcit id="pcit0016" dnum="USRE35508E"><text>Re. 35,508</text></patcit>).

0047While the invention has been described and illustrated with reference to specific embodiments, those skilled in the art will recognize that modification and variations may be made without departing from the principles of the invention as described hereinabove and set forth in the following claims.