Patent Publication Number: US-9419367-B2

Title: Pluggable connector having multiple housing shells

Description:
BACKGROUND 
     The subject matter herein relates generally to a pluggable connector having a connector housing formed from multiple housing shells. 
     Pluggable cable assemblies may be used to transfer data to and from different communication systems or devices. Known cable assemblies include serial attached (SA) small computer system interface (SCSI) cable assemblies, which may also be referred to as SAS cable assemblies. Such cable assemblies may include a pluggable connector having a mating end and a trailing end. The mating end is inserted into a receptacle assembly of the communication system, and the trailing end receives a cable of the cable assembly. In some cases, the pluggable connector includes a circuit board that has electrical contacts, such as contact pads, that are exposed at the mating end. The circuit board may be mechanically and electrically coupled to wire conductors of the cable. During a mating operation, the mating end is inserted into a cavity of the receptacle assembly. The electrical contacts at the mating end engage corresponding electrical contacts of a mating connector within the cavity. 
     Pluggable connectors may include a connector housing that is formed from multiple housing shells. For example, first and second housing shells may be joined together to define a housing cavity therebetween. The circuit board is positioned within the housing cavity between the first and second housing shells. In at least one known pluggable connector, the first and second housing shells include respective leading portions that are joined with each other to form the mating end of the pluggable connector. An elongated fastener secures the leading portions to each other. 
     While the elongated fastener may be effective in securing the leading portions together, the process of applying the elongated fastener may damage the housing shells. For example, applying the elongated fastener with excessive force may cause a crack in one or both of the housing shells. The crack(s) may cause a decrease in electrical performance and/or a decrease in an operating lifetime of the pluggable connector. In addition to the above, the elongated fastener(s) may occupy space within the pluggable connector that could be used for other purposes. 
     Accordingly, there is a need for a pluggable connector in which the leading portions of the housing shells are not joined using a fastener that extends through the housing cavity and engages the leading portions. 
     BRIEF DESCRIPTION 
     In an embodiment, a pluggable connector is provided that includes a contact array of electrical contacts for engaging corresponding contacts of a communication component. The pluggable connector also includes a connector housing having a mating end configured to mate with the communication component. The connector housing includes a first housing shell and a second housing shell that oppose each other and are coupled together to define a housing cavity therebetween. The contact array is disposed within the housing cavity. The first housing shell includes a plug collar that surrounds the contact array at the mating end. The plug collar has a leading edge and a back edge. The second housing shell interfaces with the back edge of the plug collar such that the plug collar extends from the second housing shell to the mating end. 
     In certain aspects, the connector housing may have a trailing end and a central longitudinal axis that extends between the mating and trailing ends through the housing cavity. The plug collar may surround the longitudinal axis and have at least one plug wall that extends substantially parallel to the longitudinal axis. Optionally, the at least one plug wall includes multiple plug walls that extend substantially parallel to the longitudinal axis. The leading edge of the plug collar may completely surround the longitudinal axis. 
     In certain aspects, the pluggable connector includes a circuit board having opposite side edges with the contact array positioned therebetween. The plug collar engages each of the side edges to hold the circuit board. 
     In an embodiment, a pluggable connector is provided that includes a circuit board having a contact array of electrical contacts configured to engage corresponding contacts of a communication component. The pluggable connector also includes a connector housing having a first housing shell and a second housing shell that oppose each other and are coupled together to define a housing cavity therebetween. The circuit board is disposed in the housing cavity. The connector housing has a mating end and a trailing end and a central longitudinal axis extending therebetween through the housing cavity. The second housing shell includes a front edge that faces toward the mating end and engages the circuit board. The front edge of the second housing shell is configured to block the circuit board from moving backward toward the trailing end during a mating operation with the communication component. 
     In certain aspects, the first housing shell includes a plug collar that surrounds the circuit board at the mating end. The plug collar may have a leading edge and a back edge. The second housing shell interfaces with the back edge of the plug collar such that the plug collar extends from the second housing shell to the mating end. In some cases, the front edge of the second housing shell constitutes a portion of the second housing shell that is closest to the mating end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a communication system that includes a pluggable connector formed in accordance with an embodiment. 
         FIG. 2  is a partially exploded view of the pluggable connector of  FIG. 1 . 
         FIG. 3  is an isolated view of a circuit board that may be used by the pluggable connector of  FIG. 1 . 
         FIG. 4  is an end view of a portion of the pluggable connector of  FIG. 1 . 
         FIG. 5  is an isolated front-perspective view of a housing shell that may be used with the pluggable connector of  FIG. 1 . 
         FIG. 6  is an isolated side-perspective view of another housing shell that may be used with the pluggable connector of  FIG. 1 . 
         FIG. 7  is a top view of a portion of the pluggable connector of  FIG. 1 . 
         FIG. 8  is a front perspective view of a portion of the pluggable connector of  FIG. 1 . 
         FIG. 9  is a cross-sectional view of a portion of the pluggable connector illustrating an assembly stage in which the housing shell of  FIG. 5  is mated with the housing shell of  FIG. 6 . 
         FIG. 10  is a cross-sectional view of a portion of the pluggable connector showing the housing shells joined together. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of a communication system  100  formed in accordance with an embodiment that includes a cable assembly  102  and a communication component or device  104  that are configured to engage each other. The cable assembly  102  includes a pluggable connector  106  and a pair of communication cables  236  attached to the pluggable connector  106 . Other embodiments may include only one communication cable  236  or more than one communication cable  236 . Although not shown, the cable assembly  102  may include another pluggable connector  106  at an opposite end of the communication cables  236 . The pluggable connector  106  has a connector housing  122  that includes a mating end  112  and a trailing end  114 . The mating and trailing ends  112 ,  114  may face in opposite directions along a central longitudinal axis  194  of the pluggable connector  106 . The communication cables  236  are coupled to and/or inserted through the trailing end  114  of the connector housing  122 . In certain embodiments, the pluggable connector  106  may include a coupling mechanism  108  that is coupled to the connector housing  122 . 
     For reference, the communication system  100  is oriented with respect to mutually perpendicular axes  191 - 193 , including a mating axis  191 , a lateral axis  192 , and an elevation axis  193 . In  FIG. 1 , the pluggable connector  106  is oriented such that the longitudinal axis  194  is parallel to the mating axis  191 . In the illustrated embodiment, the communication component  104  is a receptacle assembly having a cavity (not shown) for receiving a portion of the pluggable connector  106 . The communication component  104  is hereinafter referred to as the receptacle assembly  104 , but it is understood that the pluggable connector  106  may engage or mate with other communication components. 
     The mating end  112  of the connector housing  122  is configured to be inserted into the cavity of the receptacle assembly  104 . To insert the mating end  112  into the receptacle assembly  104 , the pluggable connector  106  is aligned with respect to the cavity of the receptacle assembly  104  and advanced toward the receptacle assembly  104  in a mating direction M 1 . The mating end  112  is inserted into the receptacle assembly  104  and advanced toward a mating connector (not shown) disposed within the cavity. The pluggable connector  106  and the receptacle assembly  104  may form a pluggable engagement. The coupling mechanism  108  may removably couple the pluggable connector  106  to the receptacle assembly  104  and prevent the pluggable connector  106  and the receptacle assembly  104  from being inadvertently disengaged such that data transmission is interrupted. 
     The communication cables  236  are coupled to the pluggable connector  106  at the trailing end  114 . As shown in  FIG. 2 , each of the communication cables  236  includes insulated wires  232  having jackets  234 . The jackets surround wire conductors  235  ( FIG. 3 ), which are configured to transfer data signals and/or electrical power. In other embodiments, the communication cables  236  may have optical fibers that are configured to transmit data signals in the form of optical signals. 
     Returning to  FIG. 1 , the pluggable connector  106  may be characterized as an input/output (I/O) module that is capable of being repeatedly inserted into and removed from the cavity of the receptacle assembly  104 . The communication system  100 , the cable assembly  102 , and/or the pluggable connector  106  may be configured for various applications. Non-limiting examples of such applications include host bus adapters (HBAs), redundant arrays of inexpensive disks (RAIDs), workstations, rack-mount servers, servers, storage racks, high performance computers, or switches. The communication system  100  may be, or may be part of, an external serially attached (SA) small computer system interface (SCSI). In such embodiments, the cable assembly  102  may be referred to as a serially attached SCSI (SAS) cable assembly. The cable assembly  102  may be configured for one or more industry standards, such as SAS 2.1 in which the cable assembly  102  may be capable of transmitting six (6) gigabits per second (Gbps) for each lane. In more particular embodiments, the cable assembly  102  may be configured for SAS 3.0 and/or at 12 Gbps or more per lane. The pluggable connector  106  may be configured to be compliant with small form factor (SFF) industry standards, such as SFF-8644 or SFF-8449 HD. In some embodiments, the cable assembly  102  may be similar to the cable assembly used with the Mini SAS HD Interconnect, which is available from TE Connectivity. 
     The connector housing  122  forms a housing cavity  124  that opens to the mating end  112 . The longitudinal axis  194  may extend through an approximate center of the housing cavity  124 . The connector housing  122  has an insert portion  123  that is sized and shaped to be inserted into the cavity of the receptacle assembly  104 , and a body portion  125  that is not inserted into the cavity of the receptacle assembly  104 . The insert portion  123  includes a leading edge  130  of the connector housing  122  at the mating end  112 . The body portion  125  may be configured to be gripped by an individual. 
     In the illustrated embodiment, the pluggable connector  106  includes two circuit boards  126 ,  128  having electrical contacts  127 ,  129 , respectively. The circuit boards  126 ,  128  are disposed within the housing cavity  124 . The electrical contacts  127 ,  129  are configured to engage corresponding electrical contacts (not shown) of the communication connector in the receptacle assembly  104 . In some embodiments, the electrical contacts  127 ,  129  are contact pads of the circuit boards  126 ,  128 , respectively. In alternative embodiments, however, the electrical contacts  127 ,  129  may be other types of electrical contacts, such as contact beams. 
     As shown, the connector housing  122  has first and second housing shells  136 ,  138 . The first and second housing shells  136 ,  138  may be molded from, for example, a conductive material or may include one or more conductive platings. The first and second housing shells  136 ,  138  may engage each other along a seam  140 . When coupled to each other, the first and second housing shells  136 ,  138  may define the housing cavity  124  therebetween. For instance, the housing cavity  124  may extend from the mating end  112  to the trailing end  114  between the first and second housing shells  136 ,  138 . In an exemplary embodiment, the first and second housing shells  136 ,  138  are not symmetrical. Instead, the first housing shell  136  constitutes a majority of the connector housing  122 . However, the first and second housing shells  136 ,  138  may have other configurations in alternative embodiments. Yet in other embodiments, the connector housing  122  has more than two shells. 
     The pluggable connector  106  may also include a pair of shield frames or skirts  142 A,  142 B that are coupled to the insert portion  123  to effectively surround the insert portion  123 . The shield frames  142 A,  142 B include corresponding base portions  143  and spring tabs or fingers  144 . The base portions  143  are secured to the insert portion  123 . The spring tabs  144  extend from the corresponding base portions  143  and are configured to engage an interior surface (not shown) of the receptacle assembly  104  when the insert portion  123  of the pluggable connector  106  is inserted into the receptacle assembly  104 . As shown, the spring tabs  144  may extend in a rearward direction from the corresponding base portions  143  toward the trailing end  114  and be located adjacent to the body portion  125 . The spring tabs  144  may be deflected toward the insert portion  123  when the insert portion  123  is inserted into the receptacle assembly  104 . The shield frames  142  may electrically ground an exterior of the insert portion  123  to reduce unwanted effects from electromagnetic interference (EMI). In other embodiments, a single shield frame may surround the entire insert portion  123 . 
     In some embodiments, the pluggable connector  106  includes a connector retainer  146  that is coupled to the connector housing  122 . The connector retainer  146  engages the first and second housing shells  136 ,  138  to secure the first and second housing shells  136 ,  138  to each other and form the connector housing  122 . In an exemplary embodiment, the connector retainer  146  entirely surrounds an exterior of the connector housing  122  about the longitudinal axis  194 . In other embodiments, the connector retainer  146  may only partially surround the connector housing  122 . In an exemplary embodiment, the connector retainer  146  is stamped and formed from sheet metal. However, the connector retainer  146  may be manufactured in other manners. 
     The coupling mechanism  108  includes a latch assembly  150  and an operator-controlled actuator  152 . In some embodiments, the coupling mechanism  108  may also include a portion of the connector retainer  146 . For example, the connector retainer  146  may include multiple biasing fingers  154 ,  156 . In other embodiments, the coupling mechanism  108  may include only one biasing finger. The biasing fingers  154 ,  156  extend toward the mating end  112  and engage the latch assembly  150 . The latch assembly  150  is configured to move between an open position and a closed position as described in U.S. patent application Ser. No. 14/193,185, which is incorporated herein by reference in its entirety.  FIG. 1  illustrates the latch assembly  150  in a closed position. 
     During the mating operation, when the insert portion  123  is almost entirely within the receptacle assembly  104 , a housing edge  160  of the receptacle assembly  104  may engage the latch assembly  150  thereby causing the latch assembly  150  to rotate to the open position. The biasing fingers  154 ,  156  of the coupling mechanism  108  engage the latch assembly  150  when the latch assembly  150  is in the open position and urge the latch assembly  150  back toward the closed position. Accordingly, in some embodiments, the connector retainer  146  secures the first and second housing shells  136 ,  138  together while also holding the latch assembly  150  in the closed position. In alternative embodiments, the connector retainer  146  may only secure the first and second housing shells  136 ,  138  together without engaging the latch assembly  150 . 
       FIG. 2  is a partially exploded view of the pluggable connector  106 . In particular,  FIG. 2  illustrates the first and second housing shells  136 ,  138 , the latch assembly  150 , the operator-controlled actuator  152 , the connector retainer  146 , and an interior communication sub-assembly  230 . The first and second housing shells  136 ,  138  include inner surfaces  162 ,  164 , respectively, that are configured to border each other when the first and second housing shells  136 ,  138  are joined. The first housing shell  136  has an interior surface  166  (shown in  FIG. 4 ), and the second housing shell has an interior surface  168 . The interior surfaces  166 ,  168  define at least a portion of the housing cavity  124  ( FIG. 1 ) when the first and second housing shells  136 ,  138  are joined together. 
     The first housing shell  136  includes a main body  210 , a neck section  212 , and a plug collar  214 . The second housing shell  138  also includes a main body  216  and a neck section  218 . The second housing shell  138  is open-sided such that the second housing shell  138  forms a hollowed or recessed structure that includes a cavity portion  220  defined by the interior surface  168 . Likewise, the first housing shell  136  is open-sided such that the first housing shell  136  forms a hollowed or recessed structure that includes a cavity portion  222  (shown in  FIG. 4 ) defined by the interior surface  166 . The neck section  212  joins the plug collar  214  to the main body  210 . The plug collar  214  surrounds the longitudinal axis  194  and defines a collar cavity  224 . In an exemplary embodiment, the collar cavity  224  is entirely surrounded and defined by the plug collar  214  of the first housing shell  136 . 
     When the first and second housing shells  136 ,  138  are coupled together, the cavity portions  222 ,  220  of the respective first and second housing shells  136 ,  138  and the collar cavity  224  of the plug collar  214  combine to form the housing cavity  124 . When coupled together, the main bodies  210 ,  216  directly oppose each other and the neck sections  212 ,  218  directly oppose each other. The main bodies  210 ,  216  combine to form the body portion  125  ( FIG. 1 ) of the connector housing  122 . The neck sections  212 ,  218  and the plug collar  214  combine to form the insert portion  123  ( FIG. 1 ). More specifically, the neck sections  212 ,  218  and the plug collar  214  are configured to be inserted into the cavity (not shown) of the receptacle assembly  104  ( FIG. 1 ). As shown, the plug collar  214  includes an entirety of the leading edge  130 . 
     The first and second housing shells  136 ,  138  also have respective outer active surfaces  170 ,  172 . The active surfaces  170 ,  172  have respective recess portions  174 ,  176 . The recess portions  174 ,  176  are sized and shaped to receive the latch assembly  150  when the pluggable connector  106  is fully assembled. The active surface  170  also defines a majority of a runway  180 . The runway  180  is configured to receive the operator-controlled actuator  152 . The runway  180  may include a projection  182 . 
     As shown in  FIG. 2 , the operator-controlled actuator  152  is a thin strap or tether having inner and outer surfaces  252 ,  254  and a connector end portion  256 . The operator-controlled actuator  152  is dimensioned to permit the operator-controlled actuator  152  to slide within the runway  180  along the mating axis  191  ( FIG. 1 ). During operation, the connector end portion  256  interfaces with the connector housing  122  and engages the latch assembly  150 . For example, the connector end portion  256  may slide along each of the first and second housing shells  136 ,  138  and include a cam element  260  that engages the latch assembly  150 . The connector end portion  256  also includes an opening  258  that is sized and shaped to receive the projection  182 . 
     The connector retainer  146  includes a retainer clip or shroud  186  and a retainer extension  188 . In the illustrated embodiment, the retainer clip  186  includes a plurality of retainer walls  190  that are interconnected and configured to surround an exterior of the connector housing  122 . The retainer walls  190  define a channel or passage  274 . In alternative embodiments, the retainer clip  186  may include only one retainer wall. For example, the single retainer wall may be disposed near the runway  180  when the pluggable connector  106  is fully assembled. In other embodiments, the retainer clip  186  may include only two or three retainer walls  190  without entirely surrounding the connector housing  122 . As shown in  FIG. 2 , one or more of the retainer walls  190  may include wall tabs  196 . The wall tabs  196  may be inwardly biased to flex into tab recesses  198  of the first housing shell  136 . Although not shown, the second housing shell  138  may have similar tab recesses  198 . 
     The retainer clip  186  is configured to directly engage the first and second housing shells  136 ,  138  to secure the first and second housing shells  136 ,  138  to each other. The retainer extension  188  extends in a forward direction along the mating axis  191  ( FIG. 1 ). The retainer extension  188  includes the biasing fingers  154 ,  156  and a coupling tab  270 . The coupling tab  270  is positioned between the biasing fingers  154 ,  156  and is separated from each of the biasing fingers  154 ,  156  by a gap or slot  272 . As shown, the coupling tab  270  and the biasing fingers  154 ,  156  extend generally parallel to one another. For example, in the illustrated embodiment, the coupling tab  270  and the biasing fingers  154 ,  156  are stamped from a common sheet of material, such as sheet metal. 
     When fully assembled, the pluggable connector  106  includes the communication sub-assembly  230  disposed within the housing cavity  124  ( FIG. 1 ). The communication sub-assembly  230  includes the circuit boards  126 ,  128 , the insulated wires  232 , and end portions of the communication cables  236 . Each of the communication cables  236  includes a cable jacket  238  that surrounds a plurality of the insulated wires  232 , and a cable overmold  240  that surrounds the cable jacket  238 . The cable overmold  240  may be dimensioned with respect interior dimensions of the housing cavity  124  so that the cable overmold  240  is engaged by the interior surfaces  166 ,  168  when the pluggable connector  106  is formed. 
       FIG. 3  is an enlarged view of the circuit board  128 . Although the following is with reference to the circuit board  128 , the circuit board  126  ( FIG. 2 ) may have similar features and may be coupled to the communication cables  236  ( FIG. 2 ) in a similar manner. The circuit board  128  includes a mating edge  262 , a rearward facing edge  264 , and a pair of side edges  266 ,  268 . The side edges  266 ,  268  form lateral portions  386 ,  388 , respectively, which are configured to engage the connector housing  122  ( FIG. 1 ) as described below. The wire conductors  235  include signal conductors  235 A,  235 B that are terminated to electrical contacts  242  of the circuit board  128  extending along the rearward facing edge  264 . The wire conductors  235  also include ground conductors  235 C. Although not shown, the ground conductors  235 C may be terminated to one of the electrical contacts  242  or other grounding feature (not shown). The electrical contacts  242  are electrically coupled to the electrical contacts  129  through the circuit board  128 . One or more of the electrical contacts  129  may be communicatively coupled to a processing unit  131  disposed on the circuit board  128 . The electrical contacts  129  and  242  are contact pads in the illustrated embodiment. 
     Also shown in  FIG. 3 , the mating edge  262  and the rearward-facing edge  264  face in opposite directions. The mating edge  262  is configured to engage the mating connector (not shown) within the receptacle assembly  104  ( FIG. 1 ). The electrical contacts  129  form a contact array  265  that is disposed proximate to the mating edge  262 . In the illustrated embodiment, the contact array  265  is part of the circuit board  128 . In alternative embodiments, the contact array  265  may be formed from electrical contacts that are not part of a circuit board. 
     Returning to  FIG. 2 , to assemble the pluggable connector  106 , the communication cables  236  and corresponding insulated wires  232  may be stripped to expose the wire conductors  235  ( FIG. 3 ). The wire conductors  235  may be terminated to the corresponding electrical contacts  242  ( FIG. 3 ) of the respective circuit boards  126 ,  128 . For example, the wire conductors  235  may be soldered or otherwise held against the electrical contacts  242 . Accordingly, the wire conductors  235  may be electrically coupled to the electrical contacts  127 ,  129  through the circuit boards  126 ,  128 . 
     Before, after, or during the construction of the communication sub-assembly  230 , the communication sub-assembly  230  (or components thereof) may be advanced through the channel  274  of the connector retainer  146 . The communication sub-assembly  230  may be positioned between the first and second housing shells  136 ,  138 . The first and second housing shells  136 ,  138  may be combined such that communication sub-assembly  230  is located within the housing cavity  124 . As described in greater detail below, the second housing shell  138  may be rotated into position against the first housing shell  136  for some embodiments. 
     With the connector housing  122  assembled around the communication sub-assembly  230 , the latch assembly  150  may then be positioned within the recess portions  174 ,  176 . The connector end portion  256  of the operator-controlled actuator  152  may be positioned along the connector housing  122 . The operator-controlled actuator  152  may be located above the latch assembly  150  such that the latch assembly  150  is located between the connector housing  122  and the connector end portion  256 . In an exemplary embodiment, the cam element  260  is positioned to engage the latch assembly  150 . The runway  180  receives the operator-controlled actuator  152 , and the opening  258  receives the projection  182 . 
     With the operator-controlled actuator  152  extending along the runway  180 , the connector retainer  146  may be moved in a forward direction with the operator-controlled actuator  152  extending through the channel  274  of the retainer clip  186 . The retainer extension  188  may slide along the outer surface  254  of the operator-controlled actuator  152  and over the opening  258  and the projection  182  until the biasing fingers  154 ,  156  engage the latch assembly  150 . At this time, the connector housing  122  is received within the channel  274  of the retainer clip  186 . The wall tabs  196  of the connector retainer  146  may engage the connector housing  122  and be deflected outwardly by the connector housing  122  as the connector housing  122  moves through the channel  274 . The wall tabs  196  may then flex into the tab recesses  198 . When engaged to the connector housing  122 , the wall tabs  196  prevent the connector retainer  146  from being inadvertently removed from the connector housing  122 . At some time during the assembly of the pluggable connector  106 , the shield frames  142 A,  142 B ( FIG. 1 ) are coupled to neck sections  218 ,  212 , respectively. 
     It is understood that the above assembly process is only one possible method of assembling a pluggable connector, such as the pluggable connector  106 . The assembly process may be different in other embodiments. 
       FIG. 4  is an end view of a portion of the pluggable connector  106  that illustrates the connector housing  122  and the connector retainer  146  at the trailing end  114 . For illustrative purposes, the communication sub-assembly  230  ( FIG. 2 ) and the communication cables  236  ( FIG. 1 ) are not shown. The first and second housing shells  136 ,  138  are surrounded and held together by the connector retainer  146 . The interior surfaces  166 ,  168  define a portion of the housing cavity  124  therebetween. As shown, the longitudinal axis  194  extends through an approximate center of the housing cavity  124 . The connector housing  122  may include cable openings  158 ,  159  that receive portions of the corresponding communication cables  236 . 
     In an exemplary embodiment, the first and second housing shells  136 ,  138  are joined together without using hardware. For example, the pluggable connector  106  may be devoid of any elongated fasteners, such as screws or plugs, that extend laterally through the housing cavity  124  (e.g., transverse to the longitudinal axis  194 ) to join the first and second housing shells  136 ,  138 . In some embodiments, the first and second housing shells  136 ,  138  are secured together using only the connector retainer  146  and frictional resistance between engaged surfaces of the first and second housing shells  136 ,  138 . 
       FIG. 5  is an isolated front-perspective view of the second housing shell  138 . The main body  216  includes a forward-facing body surface  302 . The neck section  218  projects parallel to the longitudinal axis  194  from the body surface  302 . The neck section  218  includes a sidewall  304  and wall portions  306 ,  308 . The sidewall  304  extends between and joins the wall portions  306 ,  308 . Each of the sidewall  304  and the wall portions  306 ,  308  has a substantially planar body that extends generally parallel to the longitudinal axis  194  when the pluggable connector  106  ( FIG. 1 ) is fully assembled. The sidewall  304  and the wall portions  306 ,  308  partially surround the longitudinal axis  194 . More specifically, the sidewall  304  and the wall portions  306 ,  308  form a portion of the hollowed or recessed structure that includes the cavity portion  220 . Also shown, the sidewall  304  extends to a step surface  309 . The wall portions  306 ,  308  include side edges  314 ,  315 , respectively, which extend parallel to the longitudinal axis  194 . The side edges  314 ,  315  face and border the first housing shell  136  ( FIG. 1 ). The wall portions  306 ,  308  also include edge segments  312 ,  313 , respectively. 
     The neck section  218  has a forward-facing front edge  310  that is collectively formed from the edge segments  312 ,  313  and an edge segment  311 . The front edge  310  (or each of the edge segments  311 - 313 ) faces generally in the mating direction M 1  along the longitudinal axis  194 . In an exemplary embodiment, the edge segments  312 ,  313  extend substantially parallel to the lateral axis  192  ( FIG. 1 ), and the edge segment  311  extends generally parallel to the elevation axis  193 . 
     Optionally, the neck section  218  includes a collar flange  316  that projects in the mating direction M 1  from the step surface  309  of the sidewall  304 . In alternative embodiments, the collar flange  316  projects from the wall portion  306  or the wall portion  308 . The collar flange  316  includes the edge segment  311  and has an inner flange surface  320  and an outer flange surface  322  with the edge segment  311  extending therebetween. In an exemplary embodiment, the edge segment  311  of the front edge  310  represents a portion of the second housing shell  138  that is proximal (or closest) to the mating end  112  ( FIG. 1 ) of the pluggable connector  106 . In some embodiments, the edge segment  311  may define a board notch  330 . The edge segment  311  is configured to border or engage the circuit board  128  ( FIG. 1 ) within the board notch  330 . 
     The outer flange surface  322  faces away from the longitudinal axis  194 . As shown, the outer flange surface  322  and the step surface  309  form an outer recess  324  of the neck section  218 . The outer flange surface  322  is offset with respect to an outer wall surface  326  of the sidewall  304 . The step surface  309  extends between the outer flange surface  322  and the outer wall surface  326 . In some embodiments, the outer recess  324  receives a portion of the plug collar  214  ( FIG. 1 ). 
       FIG. 6  is an isolated side-perspective view of the first housing shell  136 . The main body  210  includes a forward-facing body surface  342 . The neck section  212  projects from the body surface  342  parallel to the longitudinal axis  194 . The neck section  212  includes a sidewall  344  and wall portions  346 ,  348 . The sidewall  344  extends between and joins the wall portions  346 ,  348 . Each of the sidewall  344  and the wall portions  346 ,  348  has a substantially planar body that extends generally parallel to the longitudinal axis  194 . 
     The sidewall  344  and the wall portions  346 ,  348  partially surround the longitudinal axis  194 . More specifically, the sidewall  344  and the wall portions  346 ,  348  form a portion of the hollowed or recessed structure that includes the cavity portion  222 . As shown, the wall portions  346 ,  348  have respective side edges  353 ,  355  that extend parallel to the longitudinal axis  194 . The side edges  353 ,  355  are configured to interface with or border the side edges  314 ,  315  ( FIG. 5 ), respectively, when the first housing shell  136  and the second housing shell  138  ( FIG. 1 ) are coupled together. 
     The plug collar  214  is supported by the neck section  212 . In the illustrated embodiment, the plug collar  214  includes a plurality of plug walls  361 ,  362 ,  363 ,  364  that extend lengthwise in a direction that is parallel to the longitudinal axis  194 . The plug walls  362  and  364  oppose each other. The plug wall  364  extends from the sidewall  344  toward the mating end  112 . As shown, the plug walls  361 - 364  surround the longitudinal axis  194  and define the collar cavity  224 . In the illustrated embodiment, the plug walls  361 - 364  are substantially planar, but the plug walls  361 - 364  may have curved contours in other embodiments. In another embodiment, the plug collar may include a cylindrical plug wall. The first housing shell  136  may include or define an entirety of the mating end  112  of the pluggable connector  106 . Unlike other pluggable connectors that include multiple housing shells, the plug collar  214  may completely surround the circuit boards  126 ,  128  ( FIG. 1 ) proximate to the mating end  112 . As such, it may not be necessary to use elongated fasteners that, for example, extend across and join the opposing plug walls  362 ,  364 . 
     Each of the plug walls  361 - 364  includes a portion of the leading edge  130 . The plug walls  361 - 363  include edge segments  371 ,  372 ,  373 , respectively, that collectively define a back edge  370  of the plug collar  214 . The leading edge  130  and the back edge  370  face in opposite directions with the plug walls  361 - 363  extending directly therebetween. The leading edge  130  may include the mating end  112 , and the back edge  370  may face the trailing end  114  ( FIG. 1 ). At least one or more of the edge segments  371 - 373  of the back edge  370  is configured to border the front edge  310  ( FIG. 5 ) of the second housing shell  138  ( FIG. 1 ). For example, the back edge  370  and the front edge  310  may directly engage each other or face each other with a small or nominal gap therebetween. In an exemplary embodiment, when the first and second housing shells  136 ,  138  are coupled together, the edge segment  371  borders the edge segment  312  ( FIG. 5 ), the edge segment  372  extends along the collar flange  316  ( FIG. 5 ) and faces the step surface  309  ( FIG. 5 ), and the edge segment  373  borders the edge segment  313  ( FIG. 5 ). 
     The plug wall  364  includes a pair of board slots  374 ,  376 , and the plug wall  362  includes a pair of board slots  378 ,  380 . The board slots  374 ,  376  are entirely defined by the plug wall  364 . The board slots  378 ,  380 , however, are open-ended along the edge segment  372 . More specifically, the board slots  378 ,  380  may open toward the trailing end  114  ( FIG. 1 ) and/or toward the front edge  310  of the second housing shell  138 . The board slot  374  is laterally aligned with the board slot  378  such that the circuit board  126  ( FIG. 1 ) may extend across the collar cavity  224  and be received by the board slots  374 ,  378 . In a similar manner, the board slot  376  is laterally aligned with the board slot  380  such that the circuit board  128  ( FIG. 1 ) may extend across the collar cavity  224  and be received by the board slots  376 ,  380 . 
     In an exemplary embodiment, the plug wall  362  forms inner recesses  382 ,  384 . The inner recesses  382 ,  384  are sized and shaped to receive the collar flange  316 . For example, as shown in the enlarged view, the inner recess  382  is defined by a first recess surface  385  that faces toward the longitudinal axis  194  (or the plug wall  364 ) and a second recess surface  387  that faces along the longitudinal axis  194  toward the trailing end  114 . The first recess surface  385  is configured to border the outer flange surface  322  ( FIG. 5 ) of the collar flange  316 , and the second recess surface  387  is configured to border the edge segment  311  ( FIG. 5 ) of the collar flange  316 . The inner recess  384  may also have first and second recess surfaces that are similar to the first and second recess surfaces  385 ,  387 . 
       FIG. 7  is a top view of the pluggable connector  106  and, particularly, the insert portion  123  of the pluggable connector  106 . For illustrative purposes, the shield frames  142 A,  142 B ( FIG. 2 ) and the latch assembly  150  ( FIG. 2 ) are not shown. When the first and second housing shells  136 ,  138  are coupled to form the connector housing  122 , the plug collar  214  is positioned in front of the second housing shell  138 . For instance, the edge segment  312  of the second housing shell  138  borders the edge segment  371  of the first housing shell  136 . As shown in the enlarged portion of  FIG. 7 , the plug wall  362  is positioned within the outer recess  324  of the second housing shell  138 . In some embodiments, the plug wall  362  may occupy only a portion of the outer recess  324  such that a gap  391  exists between the step surface  309  and the edge segment  372 . In some embodiments, the gap  391  may receive a portion of the shield frame  142 A ( FIG. 2 ). 
       FIG. 8  is a perspective view of a portion of the pluggable connector  106 . The circuit board  128  is disposed within the collar cavity  224  of the plug collar  214 . For illustrative purposes, the circuit board  126  ( FIG. 1 ) has been removed. When the first and second housing shells  136 ,  138  are joined together along the seam  140 , the second housing shell  138  interfaces with the back edge  370  of the plug collar  214  such that the plug collar  214  extends from the second housing shell  138  to the mating end  112 . In particular embodiments, the collar flange  316  is positioned within the inner recess  382  and the edge segment  311  is engaged with the second recess surface  387 . The edge segment  311  encloses the open-ended board slots  378 ,  380 . 
     As shown in  FIG. 8 , the plug collar  214  surrounds the contact array  265 . In the illustrated embodiment, the contact array  265  of the electrical contacts  129  is part of the circuit board  128 . In other embodiments, a contact array having discreet electrical contacts that are not part of a circuit board may be disposed within the collar cavity  224 . For example, the contact array may include a two-dimensional array of pin contacts. 
     In the illustrated embodiment, the mating edge  262  of the circuit board  128  is positioned proximate to an opening  390  to the collar cavity  224 . The side edges  266 ,  268  extend along and adjacent to the plug walls  364 ,  362 , respectively. In such embodiments, the plug collar  214  may engage each of the side edges  266 ,  268  to hold the circuit board  128  within the collar cavity  224 . The circuit board  128  includes lateral portions  386 ,  388  that are received by the board slots  376 ,  380 , respectively, of the plug collar  214 . In some embodiments, the front edge  310  ( FIG. 5 ) engages at least one of the circuit boards  126 ,  128  to hold the circuit board in a designated position. For example, the edge segment  311  may engage the lateral portion  388  of the circuit board  128 . For example, the edge segment  311  may provide a backstop that engages the lateral portion  388  when the lateral portion  388  is positioned within the board slot  380 . As shown, the board notch  330  may receive the lateral portion  388 . The edge segment  311  may block the circuit board  128  from moving backward toward the trailing end  114  ( FIG. 1 ) along the longitudinal axis  194  ( FIG. 1 ) when the pluggable connector  106  is mated with the communication component  104  ( FIG. 1 ). The board slots  374 ,  378  may be configured in a similar manner to hold the circuit board  126  within the collar cavity  224 . 
       FIG. 9  is a cross-sectional view that illustrates an assembly stage just prior to the second housing shell  138  being mated with the first housing shell  136  to form the connector housing  122 .  FIG. 10  is the cross-sectional view of the fully assembled connector housing  122 . As shown, the circuit board  128  is positioned within the collar cavity  224  of the plug collar  214 . At the assembly stage shown in  FIG. 9 , the communication sub-assembly  230  is positioned within the cavity portion  222  of the first housing shell  136 . At such time, the circuit board  126  ( FIG. 1 ) and the circuit board  128  are loosely held by the plug collar  214 . 
     In some embodiments, the second housing shell  138  may be configured to slide into an intermediate position with respect to the first housing shell  136  and then rotate to a final assembled position. For example, the second housing shell  138  may be oriented with respect to the first housing shell  136 , as shown in  FIG. 9 , such that the edge segment  311  may be inserted underneath the first recess surface  385 . The collar flange  316  may be angled with respect to the longitudinal axis  194  as shown in  FIG. 9 . As the collar flange  316  is advanced in the mating direction M 1  ( FIG. 10 ) underneath the first recess surface  385 , the second housing shell  138  may be rotated toward the first housing shell  136  as indicated by the arrow R ( FIG. 10 ). As shown in  FIG. 10 , after the first and second housing shells  136 ,  138  are joined together, the first recess surface  385  interfaces with the outer flange surface  322 . At this time, the edge segment  311  ( FIG. 9 ) may directly interface with the second recess surface  387  and the circuit boards  126 ,  128  to hold the circuit boards  126 ,  128  in the designated mating positions. 
     Although the illustrated embodiment has been described as including the collar flange  316 , other embodiments may not include the collar flange  316 . In such embodiments, the back edge  370  ( FIG. 6 ) of the plug collar  214  may border at least a portion of the front edge  310  ( FIG. 5 ) without the plug collar  214  or the back edge  370  overlapping the second housing shell. 
     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 various embodiments 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 are merely exemplary 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 patentable scope should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. 
     As used in the description, the phrase “in an exemplary embodiment” and the like means that the described embodiment is just one example. The phrase is not intended to limit the inventive subject matter to that embodiment. Other embodiments of the inventive subject matter may not include the recited feature or structure. 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(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.