WO2004004072A2

WO2004004072A2 - Board connecting connector and method of producing the same

Info

Publication number: WO2004004072A2
Application number: PCT/US2002/013322
Authority: WO
Inventors: Akinori Mizumura
Original assignee: Molex Incorporated
Priority date: 2001-04-27
Filing date: 2002-04-26
Publication date: 2004-01-08
Also published as: JP2002334752A

Abstract

A backplane connector assembly includes a receptacle connector and a plug connector that is insertable into the receptacle connector. The plug connector has an insulative housing that holds a plurality of conductive pin terminals. The receptacle connector is provided with a plurality of terminals having contact portions that are brought into contact with the plug connector pin terminals, and a housing for holding the terminals. In the plug connector, a plurality of longitudinal shielding plates are provided between the pin terminals, and in the receptacle connector, a plurality of lateral shielding plates are provided between terminals so as to intersect the longitudinal shielding plates in a cross-like manner. The lateral shielding plates of the receptacle connector include slits that allow insertion of the longitudinal shielding plates. The receptacle connector housing is formed from a plurality of housing units that are stacked together in the thickness, or height, direction of the housing and are joined to each other, with the lateral shielding plates being held between adjacent housing units.

Description

Board Connecting Connector and Method of Producing the Same

Background of the Invention

The present invention relates generally to a connector for connecting two circuit boards together each other, and to a method of producing the same, and more particularly to a modular- style connector with improved shielding characteristics.

As a result of the recent reduction in the size and thickness of electronic devices, circuit board connectors are widely used for the purpose of increasing the mounting density of electronic circuits or for realizing a particular spatial arrangement of circuit boards. Such a connector includes a connector assembly that generally includes both a receptacle connector and a plug connector. In such a connector, the receptacle connector is mounted on one circuit board, and the plug connector is mounted on the other circuit board. The circuit boards are connected together in one of two ways. In one way, a pair of circuit boards are superimposed one upon the other, with the two connectors being placed between the boards. In the other way, the surface of one circuit board is arranged substantially perpendicular to the surface of the other circuit board when the plug and receptacle connectors are joined together.

Examples of the connector of the former type are disclosed in Japanese Patent Application Laid-Open Publications No. 5-275147 and 11-329636. Examples of the connector of the latter type are disclosed in Japanese Patent Application Laid-Open Publications No. 8- 288019 and 10-172652.

Recently, these board connectors have taken the form of multi-pin connectors in which the number of terminals ranges from tens to hundreds and are used as high-speed data transfer connectors. As a result, these connectors demonstrate certain problems. The first problem is related to the electromagnetic shielding of the signal terminals. In some conventional circuit board connectors, this electromagnetic shielding is partly, though not sufficiently, taken into account. For example, there exists a plug connector in which signal terminals (signal pins) are arranged in rows in the width direction of the housing and in a plurality of stages in the thickness direction of the housing. In this connector, shielding plates extend longitudinally in the housing and are simply arranged at intervals widthwise along the housing. As a result, crosstalk is generated between signal terminals between which there exists no shielding plate.

The second problem is related to the manufacturability and production cost of the receptacle connector. There exists a receptacle connector equipped with a large number of contacts arranged in a lattice-like fashion, for example, 25 pins in the widthwise direction of the housing and five pins in the thickness (top to bottom) direction of the housing. In this receptacle connector, the large number of contacts are forced into attachment holes of the housing and attached thereto. In the process, the contacts and shielding plates are alternately forced into the holes. Since the shielding plates are forced in longitudinally, only five longitudinal rows of contacts can be forced in at one time. As a result, it is necessary to perform the contact-forcing- in process and the shield-plate-forcing-in process for every 25 times each, that is, for every 50 times in total, resulting in poor manufacturability and high production cost. Needless to say, the problem of shielding described above, is not solved with this structure.

Japanese Patent Application Laid-Open Publication No. 7-114952 discloses a multipolar electric connector in which shielding is possible not only between signal terminals of different rows but also between adjacent signal terminals of the same row. This technique is suitable for a relatively simple connector with a small number of poles. However, as the number of poles increases, the number of parts including shield plates, increases steeply, resulting in an increase in production cost due to the increase in assembly man-hour and the complication of the assembly operation. Further, the larger the number of poles is, the more complicated and the more delicate the housing becomes, which leads to a problem related to formability and a problem related to the manufacturability of the mold.

The present invention is directed to a circuit board connector that may be used in backplane applications which overcomes the aforementioned disadvantages and problems.

Summary of the Invention

Accordingly, it is therefore a general object of the present invention to solve the problem of shielding and prevent the generation of crosstalk or the like and, further, to achieve, by forming the connector components as units, a reduction in the assembly time of the connector and improving the formability and manufacturability thereof to thereby achieve an overall reduction in production cost.

The present invention accomplishes these and other objects by way of its structure. In one principal aspect, the present invention provides a backplane connector assembly for connecting two circuit boards together, wherein the connector assembly includes a receptacle connector mounted on one circuit board and a plug connector mounted on the other circuit board, the two connectors orienting the circuit boards at an angle to each other. The plug connector includes an opening into which the receptacle connector is inserted, and a plurality of conductive pin terminals arranged in a lattice-like fashion in its insulative housing. The receptacle connector includes a plurality of terminals supported in an insulative housing and with contact members that engage, in electrical contact, the pin terminals of the plug connector. In the plug connector, a plurality of longitudinal shield plates are arranged parallel to each other and located between the pin terminals.

In the receptacle connector, a plurality of lateral shield plates arranged parallel to each other are provided so as to intersect the longitudinal shield plates in a cross-like fashion. Provided in the housing and the lateral shield plates of the receptacle connector are slits for allowing insertion of the longitudinal shield plates of the plug connector. The housing of the receptacle connector is formed by a plurality of housing units which are stacked together in a plurality of stages in the housing thickness direction and joined to each other, the lateral shield plates being integrally provided for the respective housing units.

In accordance with the present invention, in the receptacle connector, a plurality of lateral shield plates arranged in parallel are provided so as to intersect the longitudinal shield plates on the plug side in a cross-like fashion, so that there exist shield plates in all the spaces between the signal terminals, whereby the problem of the shielding in the connector is solved to thereby preventing the generation of crosstalk or the like.

In another aspect of the present invention, the receptacle housing and contacts are formed as units, and lateral shielding plates are integrated with the housing unit, whereby it is possible to achieve a reduction in assembly man-hour and an improvement in formability and manufacturability to thereby achieve an overall reduction in production cost. Further, due to the construction in which a plurality of housing units are stacked together in the housing thickness direction and joined to each other, it is possible to reduce the number of housing units.

When the pin terminals and the contact members of the receptacle terminals are electrically connected to each other, the peripheries of the connection portions are surrounded by longitudinal and lateral shielding plates, by which crosstalk is prevented more reliably. It is also possible for the lateral shielding plates in the present invention to be integrated with the respective housing units by insert molding. In this case, the lateral shielding plates are integrated with the housing units when they are formed, so that it is possible to achieve an improvement in both manufacturability and assembly aspects of the connector. In another aspect of the present invention, the contacts of the receptacle terminals are arranged in each of the housing units in a widthwise direction, with slits being provided between attachment holes so that it is possible to allow the longitudinal shielding plates of the plug connector side to be inserted between the attachment holes.

In another aspect of the present invention, the opposing joining surfaces of the housing units have male and female engagement portions that may be engaged together to join the housing units to each other. This engagement is a detachable one and enables the housing units to be joined to each other easily without the use of glue or other adhesives.

A plurality of contact units are provided which are connected to the rear ends of the housing units, and each contact unit is provided with a group of contacts that are received within the terminal, or attachment holes, of the receptacle housing, and a group of tails serving as leading conductors for connecting the terminals to a circuit board, with the portion of each contact unit being preferably formed by insert molding. With this structure, it is possible to connect the contact units to the housing units by fitting the contacts groups into the attachment holes. In this manner, a plurality of groups of contacts may be inserted in lateral rows into the housing.

Furthermore, the present invention provides a method for producing a receptacle connector which comprises at least three steps: firstly integrating lateral shielding plates with the housing units; secondly joining the vertically adjacent housing units to each other while stacking together the housing units provided with the shield plates in a plurality of stages; and thirdly forcing the contact units into the housing units from the rear ends thereof. In this method, a plurality of housing units may be joined to each other by stacking them together in a plurality of stages. Lateral shielding plates may then be respectively provided in the housing units, and then contact units may be connected to the rear ends of the housing units. By integrating the lateral shield plates with the housing units in advance, the structure of the receptacle connector as a whole is made simple, and the assembly thereof is facilitated.

In actually assembling the receptacle connector, the vertically adjacent housing units with their integrated shielding plates are joined to each in a plurality of stages, whereby all the contacts arranged in lateral rows can be simultaneously forced into openings in the housing units. Thus, the number of times that the contact insertion process is performed corresponds only to the number of stages or housing units which are stacked together. When the number of stacked housing units is, for example, five, the contact forcing-in process has only to be performed for five times. Thus, the number of times that the contact-forcing-in process is performed is reduced, thereby achieving an improvement in manufacturability and a reduction in production cost.

In the first step, it is desirable for the lateral shielding plates to be respectively formed into the housing units by insert molding so as to the lateral shielding plates with the housing units when forming the latter and achieve an improvement in both manufacturability and assembly.

Further, it is desirable to provide on the joint surfaces of the housing units male engagement portions and female engagement portions to be engaged with each other to thereby join the housing units to each other. This will be proved to be very convenient when performing the assembly operation by successively stacking the housing units. In another aspect, the upper stages of the housing units may slide sideways on the upper surface of the housing units directly below them to effect the engagement of the male engagement portions with the female engagement portions.

Further, the present invention provides a plug connector which utilizes a "chicklet" structure and includes a plurality of conductive pin terminals arranged in a lattice-like fashion and having their tails bent at 90 degrees for connecting the terminals to a circuit board, connection portions connecting the pin terminals to the tails, and a plurality of longitudinal shielding plates arranged parallel to each other and stacked together, with the chicklet structure being formed by insert molding. Each chicklet is formed as a unit. Due to this construction, there is no need to alternately force pin terminals and longitudinal shielding plates into the plug connector housing, also substantially reducing the time for assembly.

Each chicklet is preferably formed by providing a first carrier having a plurality of stamped pin terminals, with tail portions bent by 90 degrees for connection to the board, and connection portions for connecting the plurality of pin terminals to the tails, and a second carrier consisting of a conductive metal plate that is formed into a longitudinal shielding plate, and then insert molding the carriers. Thus, the conductive first carrier with its pin terminals and the second carrier with its longitudinal shielding plate, are superimposed one upon the other, and the insert molding is only performed for portion where it is necessary, whereby the first and second carriers are firmly secured to each other. Further, it is possible to achieve a substantial reduction time of assembly, thereby achieving an improvement in manufacturability and a reduction in production cost. These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.

Brief Description of the Drawings

In the course of this detailed description, the reference will be frequently made to the attached drawings in which:

FIG. 1 is a perspective view of a receptacle connector constructed in accordance with the principles of the present invention;

FIG. 2 is a perspective view of a plug connector constructed in accordance with the principles of the present invention;

FIG. 3 is a perspective exploded view showing how the receptacle connector of FIG. 1 is assembled;

FIGS. 4(a) and (b) are perspective views, respectively illustrating in (a) the rear side of the receptacle connector housing, and in (b) the contact, or terminal unit that is inserted into the receptacle connector housing;

FIG. 5 is a partial exploded perspective view of the plug connector of FIG. 2;

FIG. 6 is a perspective view illustrating the two carriers of the plug connector chicklet in alignment for insert molding;

FIG. 7 is the same view as FIG. 6, but taken from the other side thereof;

FIG. 8 is the same view as FIG. 6, but with an insulative housing molded around portions of the two carriers of the chicklet;

FIG. 9 is the same view as FIG. 7, but with an insulative housing molded around portions of the two carriers of the chicklet and illustrating the opposite side of the chicklet of FIG. 8; and,

FIG. 10 is a perspective view of a chicklet separated from its two carriers and used in the plug connector of the present invention.

Detailed Description of The Preferred Embodiments

FIG. 1 is a perspective view of a receptacle connector and FIG. 2 is a perspective view of a plug connector that are constructed in accordance with the principles of the present invention. The present invention involves a circuit board connector assembly that is intended for electrically connecting circuit boards in a perpendicular, or L-shaped connection, where the surfaces of the circuit boards may be considered to cross each other at right angles. This connector assembly comprises a receptacle connector 10 mounted on the surface of one circuit board (not shown) and a plug connector 20 mounted on the surface of the other circuit board (not shown).

As shown in FIG. 2, the plug connector 20 is provided with an insulative housing 22 having an opening, or channel 21, into which the receptacle connector 10 may be inserted. A plurality of conductive pin terminals 23 are arranged in the housing 22 in a lattice-like fashion. The housing 22 is of a U-shaped configuration in side profile and, as oriented in FIG.2, includes a top wall 24, a bottom wall 25, and a back or bottom wall 26. The plug housing 22 is formed such that its width W is smaller than either its height H or its length L. In the example shown in FIG. 1, the pin terminals 23 are arranged in five stages in the height direction H of the housing 22, and in three rows in the width direction W thereof, i.e., there are fifteen total pins. All the pin terminals 23 are preferably formed as rectangular pins.

The entire housing 22 is formed of an insulative material or molding resin, and the pin terminals 23 extend through the back wall 26 of the plug connector housing 22 in the thickness direction thereof, whereby the pin terminals 23 are electrically insulated from each other. Formed on the top wall 24 and the bottom wall 25 of the plug housing 22 are sloped guides 24a and 25a for facilitating the insertion of the receptacle connector 10. In the plug housing 22, a plurality of longitudinal shielding plates 27 that form a plug connector shield are arranged at equal intervals in the width direction W of the plug housing 22. Each longitudinal shielding plate 27 is preferably formed as a rectangular plate, and is further disposed between pin ' terminals 23 adjacent to each other in the width direction W of the plug housing 22. The longitudinal shielding plates 27 are arranged vertically in the orientation shown in FIG. 2, whereby each longitudinal row of pin terminals, shown as five pin terminals 23, is separated by intervening longitudinal shielding plates 27. The pin terminals 23 are of the same length, and are preferably longer than the length of the longitudinal shielding plates 27 so that they may contact an opposing connector as will be explained in detail below.

Turning to FIGS. 4a and 4b, the receptacle connector 10 can be seen to include a plurality of conductive terminals 12 each having a pair of front contact portions 11 that make electrical contact with each pin terminal 23 of the plug connector 20. The receptacle connector 10 also includes a housing 13 (FIG. 1) for holding the terminals 12 in their particular arrangement. The receptacle connector 10 includes a plurality of lateral shielding plates 14 that arranged in spaced- apart order and which are preferably parallel to each other in a manner to form a shield for the receptacle connector 10. The lateral shielding plates 14 intersect the longitudinal shield plates 27 in a cross-like fashion, when the two connectors 10, 20 are engaged together. Slits 15 are formed in both the lateral shielding plates 14 of the receptacle connector 10 so as to permit the insertion thereof into the longitudinal shielding plates 27 of the plug connector 20. (FIG. 2.)

The housing 13 of the receptacle connector 10 is composed of a plurality of individual housing units (or stages) 131-135 that are stacked together in a plurality of stages in the thickness direction of the housing 13 (vertically as shown in FIG. 1). For each of the housing units 131-135, a lateral shielding plate 14 is provided. In the lowermost stage of the housing 13, there is preferably provided a bottom housing unit 130 equipped with a lateral shielding plate 140. While there are various ways of providing the lateral shielding plates with respect to the housing units, the lateral shielding plates 14 in this example are, from the viewpoint of manufacturability, preferably formed in an integrated manner with the housing units 130-135 by a suitable process, such as by insert molding.

The lateral shielding plates 14 are arranged horizontally, and their surface area is larger than that of the longitudinal shielding plates 27 with which they mate. Each of the lateral shielding plates 14 preferably have the same general surface area. The length of each lateral shielding plate 14 is such that it protrudes beyond the rear ends of the housing units 131 through 135.

As shown in FIG. 3, formed on the joint surfaces of the housing units are male engagement portions 17 and female engagement portions 18 which engage with each other to join the housing units together. The male engagement portions 17 are provided on the upper sides of the housing units 131 through 135, and the female engagement portions 18 are provided on the lower sides thereof. These engagement portions are engaged by the so-called "hook" system, in which, as shown in FIG. 3, engagement is effected easily through sideways insertion. Numeral 16 indicates guide protrusions for guiding housing units relative to each other when they are joined together. It is possible to adopt some other hook structure for the engagement.

Each of the housing units 131-135 has one or more passages, or openings, 19 that receive the terminals 12, and these openings 19 are arranged at intervals in the width direction of the housing unit. Slits, or slots 19a, are provided between the openings 19 and receive portions of the shielding plates 27 of the plug connector 20 and also receive the ribs formed on the inner surfaces of the plug connector housing opening 21. (FIG. 2.) These ribs are aligned with the shielding plates 27 of the plug units. The receptacle connector 10 is also provided with a plurality of (five) terminal units 30 respectively connected to the rear ends of the housing units 131 through 135. A single terminal t unit is illustrated in FIG. 4(b) and a pair of such terminal units are illustrated inserted into rear faces of the housing units 131-132 of the receptacle connector. Each terminal unit 30 is provided with a group of terminals 12 with projecting contact members 11 that are received in the receptacle connector openings 19 as well as a group of tails 11a that are utilized for connecting each terminal to a circuit trace on a circuit board.

The portion of each terminal unit 30 other than the group of contact portions 11 and the group of tails 1 la includes a base, or a retainer portion 30a, formed by insert molding, and preferably this retainer portion 30a extends in the widthwise direction for the width of the housing unit in which it is inserted. The retainer portion 30a is formed from an insulative material so that each of the terminals can be electrically insulated from each other while holding them integrally. This retainer portion 30a is tightly inserted between the upper and lower lateral shield plates 14, whereby each terminal unit 30 is connected with the associated housing unit in a stably held state.

As shown in FIG. 5, the connector 20 includes a plurality of chicklets 200, wherein each such chicklet 200 is a single unit, or component, that is formed by a plurality of conductive pin terminals 23 and corresponding tails 23 a that are bent therefrom at 90 degrees for connecting the pin terminals 23 to a circuit board. Intermediate connection lines 23b that connect the pin terminals 23 to the tails 23a and a longitudinal shielding plate 27 are also formed as part of each chicklet. The pin terminals 23, tails 23a, intermediate lines 23b, and the longitudinal shielding plate 27 are all formed together into an integral unit by insert molding. Thus, the plug connector 20 illustrated in FIG. 2 is formed by the housing 22 and a plurality of (three) chicklets 200.

A plurality of insertion holes 26b are formed in the back plate 26 of the housing 22 and these holes receive the pin terminals 23 therein. Insertion holes 26b, in the form of slots, are also formed in the housing for receiving the longitudinal shielding plates 27. Thus, as shown in Fig. 5, the plug connector 20 is formed by forcing the chicklets 200 into the housing 22 from the rear or bottom thereof.

As shown in FIGS. 6-9, when producing the chicklet 200, a first carrier 210 is formed by working a conductive metal plate into the pin terminals 23, the tails 23a, and the intermediate connection lines 23b, and a second carrier 220 is prepared by stamping a second conductive metal plate into the longitudinal shielding plate 27, and the first and second carriers are superimposed one upon the other. Then, the insulative body portion 201 of the chicklet is formed, preferably by insert molding. Thereafter, the first carrier 210 and the second carrier 220 are separated by stamping, whereby the chicklet 200 as shown in FIG. 10 is obtained.

As for the receptacle connector, the plurality of housing units 130-135 which cooperatively define the housing 13 of the receptacle connector 10, the lateral shielding plates 14 that cooperatively define the receptacle connector shield, and the terminal units 30 are prepared beforehand. Thereafter, as shown in FIGS. 3 and 4, the second-stage housing unit 132 is superimposed on the upper surface of the first-stage housing unit 131, and caused to slide forwardly, so that a male engagement portion 17 thereof is engaged with an opposing female engagement portion 18 each other, with positioning of one housing unit with respect to the other being effected. Similarly, the third-, fourth-, and fifth-stage housing units are stacked and, finally, the bottom housing unit 130 is attached, whereby the receptacle housing 13 is completed. Thereafter, the terminal units 30 are forced into the housing units, thereby obtaining the receptacle connector 10 as shown in FIG. 1. The male engagement portion 17 projects forwardly from and above an elongated rib that is formed as part of the housing units. The bottom of the housing units (not shown) preferably include channels or enclosed slots that receive the ribs.

While the above assembly can be conducted manually, it is more desirable to use an automatic assembly machine. As described above, in accordance with the present invention, the problem of shielding in a connector to prevent crosstalk or the like is solved. By forming the connector components as units, it is possible to achieve a reduction in assembly time and an improvement in forming and manufacturability, thereby making it possible to achieve an overall reduction in production cost.

While the preferred embodiment of the invention have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made therein without departing from the spirit of the invention, the scope of which is defined by the appended claims.

Claims

CLAIMS:

1. A backplane connector for connecting two circuit boards together, comprising: a receptacle connector for mounting to one of the circuit boards, the receptacle connector including an insulative housing having a plurality of terminal-receiving passages formed therein, the passages being arranged in said housing in rows and columns, each of said passages including a conductive terminal disposed therein, said receptacle connector further including a plurality of first shielding plates disposed therein between rows of said passages, the first shielding plates extending through said housing in a widthwise direction, said housing and said first shielding plates each having slits formed there in which are aligned together and which cooperatively define a plurality of slots in said receptacle connector that are disposed between adjacent columns of said housing passages, each of said terminals including a contact portion, a tail portion and a body portion interconnecting the contact and tail portion together; and, a plug connector for mounting to the other of said two circuit boards, the plug connector being matable with said receptacle connector, the plug connector including an insulative housing having an opening which said receptacle connector when said plug and receptacle connectors are mated together, and a plurality of conductive pin terminals disposed in said plug connector housing in a lattice arrangement in rows and columns, the arrangement of said pin terminals matching the arrangement of said receptacle connector terminals so that one pin terminal is received within a single terminal- receiving passage of said receptacle connector when said plug connector and receptacle connector are mated together, each of said pin terminals including a contact portion, a tail portion and a body portion interconnecting said contact and tail portions together, said plug connector further including a plurality of conductive second shielding plates disposed therein in and spaced apart from each other, the second shielding plates having an extent that projects within said opening so that they are received within said receptacle connector slots when said plug and receptacle connectors are mated together, said plug connector further including a plurality of discrete plug units insertable in said plug connector housing, each of the plug units including a plurality of pin terminals and at least one of said second shielding plates integrally formed therewith.

2. The backplane connector of Claim 1, wherein said first and second shielding plates each include mating ends, the mating ends of said first and second shielding plates electrically contacting each other and surrounding said contact portions of said plug connector pin terminals and said receptacle connector terminals when said plug and receptacle connectors are mated together.

3. The backplane connector of Claim 1 , wherein said receptacle connector housing is formed from a plurality of individual housing units, each of the individual housing units including a plurality of said terminal-receiving passages aligned with each other, and said first shielding plates are interposed between adjacent housing units.

4. The backplane connector of Claim 1 , wherein said plug housing includes a plurality of holes arranged in rows and columns, each of the holes receiving a single pin terminal therein so that said pin terminal contact portions project into said plug connector opening, and a plurality of second slots, each of the second slots being spaced apart from and disposed adjacent a column of said holes, such that when said units are inserted into said plug connector, said second shielding plates project through said slots into said plug connector opening.

5. The backplane connector of Claim 1 , wherein said receptacle connector housing units include male and female engagement portions that engage each other when two of said housing units are joined together.

6. The backplane connector of Claim 5, wherein said receptacle connector housing terminal-receiving passages include an angled leading edge, and receptacle housing unit male engagement portions include a portion of said leading edge.

7. The backplane connector of Claim 1 , wherein said receptacle connector includes a plurality of terminal units, each terminal unit including a retainer member that supports a plurality of said receptacle connector terminals in a manner so that said contact portions and said tail portions thereof extend from opposite ends of the retainer member, said base member fitting onto a rear end of one of said receptacle connector housing units so that said terminal contact portions are received within said housing terminal-receiving passages.

8. The backplane connector of Claim 7, wherein said retainer member is molded onto said terminals over said body portions thereof.

9. The backplane connector of Claim 1, wherein said plug units include an insulative housing portion that is molded over portions of said pin terminals and second shielding plates.

10. The backplane connector of Claim 1, wherein said pin terminals and said second shielding plates are separately formed from two distinct sheets of metal and said housing portion is molded over portions thereof.

11. The backplane connector of Claim 1 , wherein said plug connector housing includes a channel portion formed in a base thereof which receives said plug units.

12. The backplane connector of Claim 4, wherein said plug connector housing includes a plurality of ribs disposed on opposite sides of said opening, said ribs being aligned with said plug connector housing slots, said ribs being received within said receptacle connector housing slots.