Patent Publication Number: US-2011059625-A1

Title: Modular connector system

Description:
BACKGROUND OF THE INVENTION 
     The invention relates generally to electrical connectors and, more particularly, to a connector system that is capable of mating with several mating connectors. 
     Known connector systems include several connectors within a connector cage. The connector cage typically is a conductive body that is electrically coupled with an electric ground reference. The connector cage may include ports that are shaped to receive mating connectors. The connectors located in the connector cage are located within the ports such that these connectors mate with the mating connectors when the mating connectors are inserted into the ports. The connector cage may shield the connectors from electromagnetic interference. 
     Some of these known connector systems provide two or more of the connectors in the connector cage in a vertically stacked arrangement. For example, a pair of the connectors may be disposed above and below one another with the lower connector mounted to a circuit board and the upper connector coupled with the lower connector. By way of example only, the upper and lower connectors may be included in a single, unitary common housing with separate mating interfaces that mate with the mating connectors. The common housing of the connectors can be mounted to a circuit board. The connector cage of the system also may be mounted to the same circuit board. 
     Typically, the connectors in the cage include contacts that mate with and electrically couple with corresponding contacts of the mating connectors. The contacts of the connectors in the cage may extend from the mating interfaces of the connectors to the circuit board to which the housing of the connectors is mounted. Alternatively, the contacts may be electrically coupled with the circuit board via one or more additional conductive components. In either case, conductive signal paths for the contacts may extend from the mating interfaces of the connectors to the circuit board to electrically couple the mating connectors with the circuit board when the mating connectors mate with the connectors in the connector cage. 
     The signal paths for the contacts in the upper connector of the connector cage may be significantly longer than the signal paths for the contacts in the lower connector. For example, the distances that data signals must travel through the connectors to the circuit board may be greater for the upper connector than for the lower connector. In connector systems where relatively high data rates are used to communicate data using the connectors, the increased distance that the signals must pass may increase cross-talk in the signals. 
     A need exists for connector systems that include multiple connectors capable of relatively high speed data communication while reducing cross-talk among or between contacts or signal paths associated with the connectors. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, a connector assembly is provided. The connector assembly includes a subsidiary circuit board, connectors, and an interposer assembly. The subsidiary circuit board includes opposite sides. The connectors are mounted to the opposite sides of the subsidiary circuit board and are electrically coupled with the subsidiary circuit board. The connectors are configured to mate with mating connectors. The interposer assembly is joined with the subsidiary circuit board. The interposer assembly includes a dielectric housing and elongated contacts that extend between opposite outer ends along a vertical axis and are held by the housing. The interposer assembly mates with the subsidiary circuit board and is configured to mate with a main circuit board such that the outer ends of the contacts electrically couple the connectors mounted to the subsidiary circuit board with the main circuit board. 
     In another embodiment, another connector assembly is provided. The connector assembly includes a connector cage, a subsidiary circuit board, a connector, an interposer assembly, and a push block. The connector cage includes a port that is configured to receive a mating connector into the connector cage. The connector cage is adapted to be mounted to a main circuit board. The subsidiary circuit board is disposed within the connector cage between the ports. The connector is mounted to and electrically coupled with the subsidiary circuit board. The connector is disposed within the port of the connector cage and is configured to mate with the mating connector to electrically couple the mating connector with the subsidiary circuit board. The interposer assembly is mounted to the subsidiary circuit board and is configured to mate with the main circuit board. The interposer assembly includes contacts that are configured to mate with and electrically couple the subsidiary circuit board with the main circuit board. The push block is disposed between the subsidiary circuit board and the connector cage. The push block receives a loading force that is applied to the connector cage and transfers the loading force to the interposer assembly to mate the interposer assembly with the main circuit board. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial cut-away view of a connector cage system in accordance with one embodiment of the present disclosure. 
         FIG. 2  is an exploded view of the connector cage system shown in  FIG. 1  in accordance with one embodiment of the present disclosure. 
         FIG. 3  is a perspective view of an interposer assembly shown in  FIG. 1  in accordance with one embodiment of the presently disclosure. 
         FIG. 4  is a cross-sectional view of the interposer assembly shown in  FIG. 1  taken along line  4 - 4  in  FIG. 3  in accordance with one embodiment of the present disclosure. 
         FIG. 5  is a cross-sectional view of the interposer assembly shown in  FIG. 1  taken along line  5 - 5  shown in  FIG. 3  in accordance with one embodiment of the present disclosure. 
         FIG. 6  is a perspective view of a push block shown in  FIG. 1  in accordance with one embodiment of the present disclosure. 
         FIG. 7  is another perspective view of the push block shown in  FIG. 1  in accordance with one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a partial cut-away view of a modular connector system  100  in accordance with one embodiment of the present disclosure.  FIG. 2  is an exploded view of the modular connector system  100  in accordance with one embodiment of the present disclosure. The system  100  includes a connector assembly  102  mounted to a main circuit board  104  and disposed within a connector cage  106 . The connector cage  106  may be mounted to the main circuit board  104  to electrically couple the connector cage  106  with an electric ground reference of the main circuit board  104 . The connector cage  106  may shield the connector assembly  102  from electromagnetic interference by being joined to the electric ground reference of the main circuit board  104 . 
     The connector cage  106  is a conductive body that includes a top wall  108 , several opposing side walls  110 , a rear wall  112 , and a bottom wall  114 . A dividing or separator plate  118  is disposed between adjacent pairs of the side walls  110  to form upper and lower ports  116 . One or more of the side walls  110  may include retention slots  208 ,  210  (shown in  FIG. 2 ). The retention slots  208 ,  210  engage tabs  212 ,  214  on the connector assembly  102  to secure the connector assembly  102  to the connector cage  106 . As shown in  FIG. 1 , the connector cage  106  includes multiple ports  116  that are formed by the walls  108 - 114  and plates  118 . The ports  116  receive mating connectors (not shown) that mate with the connector assembly  102  to communicate data and/or power therebetween. By way of non-limiting example only, the ports  116  may have dimensions that are sized to receive a small form-factor pluggable connector or transceiver that mates with the connector assembly  102 . 
     The connector assembly  102  includes a subsidiary circuit board  120  to which two connectors  122 ,  124  are mounted. By way of non-limiting example only, the connectors  122 ,  124  may be mounted to surfaces of the subsidiary circuit board  120  or through-hole mounted to the subsidiary circuit board  120 . The connectors  122 ,  124  are shown in a stacked arrangement with one connector  122  located above the other connector  124  along a vertical axis  132  of the connector assembly  102 . For example, the connectors  122 ,  124  are stacked above one another in groups or pairs in the illustrated embodiment. Such an embodiment may be referred to as a vertically stacked modular connector assembly. Alternatively, the connectors  122 ,  124  may be mounted side-by-side along a lateral axis  138  of the connector assembly  102 . The connectors  122 ,  124  are electrically coupled with the subsidiary circuit board  120 . For example, the connectors  122 ,  124  may include contacts  130  that are electrically joined with conductive traces (not shown) extending along and/or through the subsidiary circuit board  120 . The number of connectors  122 ,  124  shown mounted to the subsidiary circuit board  120  in  FIG. 1  is merely an example. A different number of the connectors  122 ,  124  may be provided. For example, only a single connector  122 ,  124  may be mounted to the subsidiary circuit board  120 . In the illustrated embodiment, the connectors  122 ,  124  are mounted to different sides  126 ,  128  of the subsidiary circuit board  120 . The sides  126 ,  128  are opposite one another such that the connectors  122 ,  124  extend away from the subsidiary circuit board  120  in opposite directions. 
     The subsidiary circuit board  120  is positioned within the connector cage  106  between the top wall  108  and the main circuit board  104 . The subsidiary circuit board  120  is disposed between the ports  116  along the vertical axis  132  of the connector assembly  102 . The subsidiary circuit board  120  may be located between the ports  116  such that the connectors  122 ,  124  are aligned with different ports  116  and positioned to mate with the mating connectors (not shown) that are inserted or loaded into the ports  116  to electrically couple with the mating connectors. 
     An interposer assembly  134  is coupled with the subsidiary circuit board  120 . The interposer assembly  134  may be mounted to and electrically coupled with the subsidiary circuit board  120 . For example, the interposer assembly  134  may include signal contacts and ground contacts  200 ,  202  (shown in  FIG. 2 ) having upper ends  322  (shown in  FIG. 3 ) that mate with the subsidiary circuit board  120 , and lower ends  324  (shown in  FIG. 3 ) that mate with the main circuit board  104  when the connector assembly  102  is mounted to the main circuit board  104 . The contacts  200 ,  202  of the interposer assembly  134  electrically couple the subsidiary circuit board  120  with the main circuit board  104 . The mating connectors (not shown) that mate with the connectors  122 ,  124  may be electrically connected with the main circuit board  104  via the subsidiary circuit board  120  and the interposer assembly  134 . 
     As described below, the interposer assembly  134  may arrange the signal and ground contacts  200 ,  202  (shown in  FIG. 2 ) in a pattern that reduces or eliminates noise and/or crosstalk in signals communicated using the signal contacts  200 . The signal and ground contacts  200 ,  202  may be arranged in the interposer assembly  134  to communicate data signals at relatively high data rates. By way of example only, the connector assembly  102  may be capable of communicating data signals through the interposer assembly  134  at data rates of at least approximately 10 Gigabytes per second. In another example, the data rate may be approximately 16 Gigabytes per second or greater. 
     A push block  136  is provided within the connector cage  106  between the subsidiary circuit board  120  and the connector cage  106 . In the illustrated embodiment, the push block  136  is located on top of the side  126  of the subsidiary circuit board  120  between the side  126  and the top wall  108  of the connector cage  106 . The push block  136  also is shown as being located behind the connector  122  between the connector  122  and the rear wall  112  of the connector cage  106  and between adjacent side walls  110 , with one of the side walls  110  not shown in  FIG. 1 . The push block  136  transfers a loading force applied to the connector cage  106  to the interposer assembly  134  to seat the connector assembly  102  onto the main circuit board  104 . For example, a loading force may be applied to the top wall  108  of the connector cage  106  in a direction generally along the longitudinal axis  132  and represented by the arrow  140  in  FIG. 1 . The loading force may be transferred to the subsidiary circuit board  120  by the push block  136 . The loading force may force the subsidiary circuit board  120  and the interposer assembly  134  downward along the longitudinal axis  132  and toward the main circuit board  104 . The loading force seats or loads the lower ends  324  (shown in  FIG. 3 ) of the signal and ground contacts  200 ,  202  (shown in  FIG. 2 ) of the interposer assembly  134  into corresponding contact openings  204 ,  206  (shown in  FIG. 2 ) in the main circuit board  104 . The lower ends  324  of the signal and ground contacts  200 ,  202  are forced into the contact openings  204 ,  206  to mount the connector assembly  102  to the main circuit board  104 . 
     The push block  136  prevents the loading force from damaging or altering the structure of one or more components of the connector assembly  102 . For example, the push block  136  may have a height dimension  142  (shown in  FIG. 1 ) measured in along an axial direction that is oriented parallel to the vertical axis  132 . The height dimension  142  of the push block  136  may be greater than a height dimension  144  (shown in  FIG. 1 ) of the connector  122  measured in the same direction as the height dimension  142 . The greater height dimension  142  of the push block  136  results in the loading force causing the connector cage  106  to contact and engage the push block  136  prior to or without engaging the connector  122 . The push block  136  receives the loading force and prevents the connector cage  106  from bending downward and damaging or contacting the connector  122 . In one embodiment, the height dimension  142  of the push block  136  is the greatest height dimension of all components and devices that are mounted or extending upward from the side  126  of the subsidiary circuit board  120 . 
       FIG. 3  is a perspective view of the interposer assembly  134  in accordance with one embodiment of the present disclosure. The interposer assembly  134  includes a housing  300  that extends between a mating side  302  and an opposite mounting side  304  along the vertical axis  132 , between opposite front and rear sides  306 ,  308  along a transverse axis  310 , and between opposite sides  312 ,  314  along the lateral axis  138 . In the embodiments illustrated in  FIGS. 1-3 , the vertical, lateral, and transverse axes  132 ,  138 ,  310  are disposed at right angles with respect to one another and intersect one another within the interposer assembly  134 . In the embodiment shown in  FIG. 1 , the housing  300  extends between the subsidiary circuit board  120  (shown in  FIG. 1 ) and the main circuit board  104  (shown in  FIG. 1 ). For example, the side  302  of the interposer assembly  134  engages the side  128  (shown in  FIG. 1 ) of the subsidiary circuit board  120  and the side  304  of the interposer assembly  134  engages the main circuit board  104  when the connector assembly  102  (shown in  FIG. 1 ) is mounted to the main circuit board  104 . The housing  300  includes, or is formed from, a dielectric material, such as one or more nonconductive polymers in one embodiment. For example, the housing  300  may be molded from one or more thermoplastic polymers. 
     The housing  300  includes the tab  214  projecting from the side  312  in a direction parallel to the lateral axis  138 . Alternatively, the tab  214  may project from a different side  302 ,  304 ,  306 ,  308 ,  314  and/or in a different direction. The tab  214  may be received in the retention slot  210  (shown in  FIG. 2 ) of the connector cage  106  (shown in  FIG. 1 ) to secure the interposer assembly  134  to the connector cage  106 . In one embodiment, prior to closing the rear side of the connector cage  106  with the rear wall  112  (shown in  FIG. 1 ) by, for example, bending the rear wall  112  downward to enclose the rear side of the connector cage  106 , the connector assembly  102  (shown in  FIG. 1 ) may be loaded into the connector cage  106  through the rear side of the connector cage  106  by sliding the tab  214  into the retention slot  210 . The engagement between the retention slot  210  and the tab  214  may limit or prevent movement of the connector cage  106  relative to the interposer assembly  134  and/or connector assembly  102  in one or more directions. 
     The housing  300  includes contact channels  318 ,  320  that extend from the side  302  toward the side  304 . In one embodiment, the contact channels  318 ,  320  extend through the housing  300  from the side  302  to the side  304 . As shown in  FIG. 3 , the contact channels  320  are wider in a direction along the lateral axis  138  than the contact channels  318  while the contact channels  318 ,  320  have approximately the same width in a direction along the transverse axis  310 . 
     The signal and ground contacts  200 ,  202  are disposed within the contact channels  318 ,  320 . The signal and ground contacts  200 ,  202  extend between an outer end  322  and a lower end  324  which may simply be termed opposite outer ends. The outer ends  322 ,  324  may differ from one another or be substantially the same. For example, in the embodiment shown in  FIG. 3 , the outer ends  322  of the signal and ground contacts  200 ,  202  differ from the outer ends  324  of the signal and ground contacts  200 ,  202 . The outer ends  322  are loaded into or otherwise mate with the subsidiary circuit board  120  (shown in  FIG. 1 ) while the outer ends  324  are loaded into or otherwise mate with the main circuit board  104  (shown in  FIG. 1 ) to electrically couple the subsidiary circuit board  120  with the main circuit board  104 . The illustrated outer ends  322  are solder tail contact ends that may be loaded into openings (not shown) in the subsidiary circuit board  120  (shown in  FIG. 1 ) and soldered to the subsidiary circuit board  120 . The illustrated outer ends  324  are eye-of-needle (EON) contact tails that may be press-fit into the contact openings  204 ,  206  (shown in  FIG. 2 ) of the main circuit board  104  (shown in  FIG. 1 ). 
       FIG. 4  is a cross-sectional view of the interposer assembly  134  taken along line  4 - 4  in  FIG. 3  in accordance with one embodiment of the present disclosure. The tab  214  (shown in  FIG. 2 ) is not shown in  FIG. 4 . The signal and ground contacts  200 ,  202  are elongated contacts oriented in directions along the longitudinal axis  132  (shown in  FIG. 1 ). The signal and ground contacts  200 ,  202  have corresponding length dimensions  412 ,  414  that are measured between the tips of the outer ends  322 ,  324  in directions parallel to the longitudinal axis  132 . The length dimensions  412 ,  414  may be approximately the same or may differ from one another. 
     The outer ends  322 ,  324  of the signal contacts  200  are interconnected by a body section  404 . The body sections  404  of the signal contacts  200  have approximately constant width dimensions  406  in directions parallel to the lateral axis  138  in the illustrated embodiment. The outer ends  322 ,  324  of the ground contacts  202  are interconnected by a body section  408 . The body sections  408  of the ground contacts  202  have approximately constant width dimensions  410  in directions parallel to the lateral axis  138  in the illustrated embodiment. The body sections  408  of the ground contacts  202  may have greater width dimensions  410  than the width dimensions  406  of the signal contacts  200 . 
     The outer ends  322  include the portions of the signal and ground contacts  200 ,  202  that protrude from the body sections  404 ,  408  of the signal and ground contacts  200 ,  202 . For example, the outer ends  322  of the signal and ground contacts  200 ,  202  may include the sections of the signal and ground contacts  200 ,  202  that have substantially identical dimensions and that protrude from one of the sides  302 ,  304 ,  306 ,  308 ,  312 ,  314  of the interposer assembly  134 . Alternatively, the outer ends  322  of the signal and ground contacts  200 ,  202  may differ from one another. The outer ends  324  of the signal and ground contacts  200 ,  202  extend from the body sections  404 ,  408  in an opposite direction than the outer ends  202 . As shown in  FIG. 4 , the outer ends  324  protrude from the side  304  of the interposer assembly  134 . The outer ends  324  may be eye-of-needle pins that are inserted into the main circuit board  104  (shown in  FIG. 1 ) to electrically couple the signal and ground contacts  200 ,  202  with the main circuit board  104 . Alternatively, the outer ends  324  may have different dimensions and/or sizes. 
       FIG. 5  is a cross-sectional view of the interposer assembly  134  taken along line  5 - 5  shown in  FIG. 3  in accordance with one embodiment of the present disclosure.  FIG. 5  illustrates the pattern, or spatial arrangement, of the signal and ground contacts  200 ,  202  relative to one another in a plane disposed parallel to the sides  302  (shown in  FIG. 3) and 304  in one embodiment. The pattern shown in  FIG. 5  includes several rows  500 - 510  of the contacts  200 ,  202 . The rows  500 - 510  include sets or groups of the signal and ground contacts  200 ,  202  with the contacts  200 ,  202  linearly aligned with one another in directions oriented along the lateral axis  138 . For example, the planar bodies  404 ,  408  (shown in  FIG. 4 ) of the signal and ground contacts  200 ,  202  in each row  500 - 510  may be disposed in a common plane with one another, with the common plane oriented approximately parallel to the front and rear sides  306 ,  308  of the interposer assembly  134 . 
     In each of the rows  500 - 510  shown in  FIG. 5 , the signal contacts  200  are arranged in several pairs  512 , with two signal contacts  200  disposed adjacent to one another in each pair  512 . A single one of the ground contacts  202  is located between adjacent pairs  512  of the signal contacts  200  in the rows  500 - 510 . Alternatively, a different number of signal contacts  200  may be provided in groups along each row  500 - 510  instead of the signal contacts  200  being provided in the pairs  512 . In another embodiment, a different number of ground contacts  202  may be provided between adjacent groups or pairs  512  of the signal contacts  200 . The ground contacts  202  are separated from adjacent pairs  512  of the signal contacts  200  by a lateral air gap  526 . The lateral air gap  526  may be a spatial separation between the ground contacts  202  and the signal contacts  200  in directions along the lateral axis  138  where no portion of the housing  300  or other component is disposed. 
     The signal and ground contacts  200 ,  202  also are arranged in several columns  514 - 520  in the pattern shown in  FIG. 5 . The columns  514 - 520  may be oriented along linear directions that are oriented perpendicular to the rows  500 - 510 . For example, the columns  514 - 520  include several of the pairs  512  of the signal contacts  200  and several of the ground contacts  202  aligned with one another along directions that are parallel to the transverse axis  310 . The bodies  404 ,  408  (shown in  FIG. 4 ) of the signal and ground contacts  200 ,  202  in each column  514 - 520  are oriented in planes that are not common with one another. For example, the planar bodies  404 ,  408  of the signal and ground contacts  200 ,  202  in each column  514 - 520  may be oriented approximately parallel with respect to one another and approximately perpendicular to the linear direction over which each column  514 - 520  extends. Each column  514 - 520  includes pairs  512  of the signal contacts  200  that are separated from one another by a single one of the ground contacts  202 . For example, the pairs  512  of the signal contacts  200  that are adjacent to one another in each column  514 - 520  are separated from one another by a single ground contact  202 . Alternatively, a different number of the ground contacts  202  may be provided between adjacent pairs  512  of the signal contacts  200  along the columns  514 - 520 . The signal and ground contacts  200 ,  202  may be arranged in the rows  500 - 510  and columns  514 - 520  such that an individual ground contact  202  separates adjacent pairs  512  of the signal contacts  200  along the rows  500 - 510  and a different individual ground contact  202  separates adjacent pairs  512  of the signal contacts  200  along the columns  514 - 520 . 
     The housing  300  of the interposer assembly  134  includes lateral interior walls  522  that extend between the opposite sides  312 ,  314 . The lateral interior walls  522  are oriented approximately parallel to one another and to the front and rear sides  306 ,  308  of the interposer assembly  134 . As shown in  FIG. 5 , the lateral interior walls  522  are oriented parallel to the lateral axis  138 . The lateral interior walls  522  may extend from the mating side  302  (shown in  FIG. 3 ) to the mounting side  304  of the housing  300 . The lateral interior walls  522  separate the rows  500 - 510  of the contacts  200 ,  202  from one another. For example, each lateral interior wall  522  may separate adjacent rows  500 - 510  of the signal and ground contacts  200 ,  202  from each other. As shown in  FIG. 5 , the contacts  200 ,  202  in adjacent rows  500 - 510  abut opposite sides of the lateral interior walls  522 . For example, the signal and ground contacts  200 ,  202  in the row  500  and the signal and ground contacts  200 ,  202  in the row  502  abut the opposite sides of the lateral interior wall  522  that separates the rows  500 ,  502  from one another. The lateral interior walls  522  separate the ground contacts  202  from the pairs  512  of the signal contacts  200  within the columns  514 - 520 . For example, the ground contacts  202  are separated from adjacent ones of the pairs  512  of the signal contacts  200  by the lateral interior walls  522  within each of the columns  514 - 520 . The signal and/or ground contacts  200 ,  202  may be separated from an adjacent lateral interior wall  522  by a transverse air gap  528 . The transverse air gap  528  is a spatial separation between a signal and/or ground contact  200 ,  202  and a lateral interior wall  522  in a direction along the transverse axis  310 . In one embodiment, no portion of the housing  300  or any other component is provided in the transverse air gap  528 . 
     The housing  300  shown in  FIG. 5  includes transverse interior walls  524  that extend between the lateral interior walls  522 . For example, the transverse interior walls  524  couple adjacent ones of the lateral interior walls  522  with one another. The transverse interior walls  524  are oriented approximately parallel to one another and to the opposite sides  312 ,  314  of the housing  300 . As shown in  FIG. 5 , the transverse interior walls  524  also are oriented parallel to the transverse axis  310 . The transverse interior walls  524  may extend from the mating side  302  (shown in  FIG. 3 ) to the mounting side  304  of the housing  300 . The transverse interior walls  524  are portions of the housing  300  that separate the signal contacts  200  from one another in the groups or sets of signal contacts  200 . For example, the transverse interior walls  524  separate the signal contacts  200  in the pairs  512  of signal contacts  200  from one another. As shown in  FIG. 5 , the signal contacts  200  on opposite sides of the transverse interior walls  524  abut the opposite sides of the transverse interior walls  524 . Alternatively, an air gap or separation gap may exist between the signal contacts  200  and the transverse interior walls  524 . 
     The location or arrangement of the signal contacts  200 , ground contacts  202  and one or more portions of the housing  300  may reduce cross-talk and/or electromagnetic interference in the interposer assembly  134 . For example, the lateral interior walls  522  located between the ground contacts  202  and adjacent pairs  512  of the signal contacts  200  in directions parallel to the transverse axis  310  may increase the coupling between the signal and ground contacts  200 ,  202 . The coupling between the signal and ground contacts  200 ,  202  may be energy coupling, capacitive coupling, and/or inductive coupling. Increasing the coupling between the signal and ground contacts  200 ,  202  using the dielectric lateral interior walls  522  may increase an electric impedance characteristic of the interposer assembly  134 . For example, increasing the coupling between the contacts  200 ,  202  via the lateral interior walls  522  may increase an electric capacitive characteristic of the interposer assembly  134 . As a result, cross-talk between the signal contacts  200  may be reduced. Providing ground contacts  202  between the pairs  512  of signal contacts  200  in directions parallel to the lateral axis  138  may reduce electromagnetic interference in the interposer assembly  134 . For example, the ground contacts  202  may be coupled with an electric ground reference of the main circuit board  104  (shown in  FIG. 1 ) to transfer electromagnetic interference in the interposer assembly  134  to the ground reference. 
       FIG. 6  is a perspective view of the push block  136  in accordance with one embodiment of the present disclosure.  FIG. 7  is another perspective view of the push block  136  in accordance with one embodiment of the present disclosure. The push block  136  may include, or be formed from, a dielectric material. For example, the push block  136  may be molded from one or more polymers. Alternatively, the push block  136  may include, or be formed from, a conductive material, such as a metal or metal alloy. The push block  136  extends between opposite top and bottom sides  600 ,  602  in a direction along the vertical axis  132 , between opposite sides  604 ,  606  in a direction parallel to the lateral axis  138  (shown in  FIG. 1 ), and between opposite front and rear sides  608 ,  610  in a direction parallel to the transverse axis  310  (shown in  FIG. 3 ) 
     The push block  136  includes tabs  612 ,  700  (shown in  FIG. 7 ) that protrude from the sides  604 ,  606 . One or more of the tabs  612 ,  700  may be received in retention slots  208  (shown in  FIG. 2 ) in the connector cage  106  (shown in  FIG. 1 ) to secure the push block  136  to the connector cage  106 . For example, the tab  612  may be slid into the retention slot  208  and the tab  700  may be slid into a similar retention slot (not shown) in one of the side walls  110  (shown in  FIG. 1 ). 
     The push block  136  includes crossing interior walls  614 ,  616 . The interior wall  614  is oriented approximately parallel to the vertical and lateral axes  132 ,  138  (shown in  FIG. 1 ) and the interior wall  616  is oriented approximately parallel to the vertical and transverse axes  132 ,  310  (shown in  FIG. 3 ). The interior wall  614  extends between the sides  604 ,  606  and from the top side  600  to the bottom side  602 . The interior wall  616  extends between the front and rear sides  608 ,  610  and from the top side  600  to the bottom side  602 . The interior walls  614 ,  616  intersect one another within the interior of the push block  136 . In the illustrated embodiment, the interior walls  614 ,  616  define four channels  702 - 708  that extend through the push block  136  from the top side  600  to the bottom side  602 . Alternatively, a different number of interior walls  614 ,  616  and/or interior channels  702 - 708  may be provided. 
     The interior walls  614 ,  616  and/or the sides  604 - 610  receive the loading force applied along the direction of the arrow  140  (shown in  FIG. 1 ) at the top side  600  and transfer this force to the bottom side  602  of the push block  136 . The loading force is transferred to the subsidiary circuit board  120  (shown in  FIG. 1 ) to push the contacts  200 ,  202  (shown in  FIG. 2 ) into the main circuit board  104  (shown in  FIG. 1 ) to seat the contacts  200 ,  202  in the main circuit board  104 , as described above. 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and merely are example embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means—plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.