Patent Publication Number: US-2023138913-A1

Title: Circuit board assembly for a communication system

Description:
BACKGROUND OF THE INVENTION 
     The subject matter herein relates generally to communication systems. 
     Communication systems use electrical connectors to electrically connect various components to allow data communication between the components. For example, in a backplane system, circuit board assemblies having electrical connectors mounted to circuit boards are mated to electrically connect the circuit boards. Alignment of the electrical connectors during mating is difficult and misalignment may lead to damage of components of the electrical connectors. The system may include an equipment rack used to support the circuit board assemblies relative to each other. Known rack mount circuit board backplane connectors typically need to absorb large dimensional tolerance accumulation of the relative distance between the circuit boards inserted from both sides of the equipment rack. Typical tolerance distances may be 1.5 mm or more. The contacts of the backplane connectors at the mating zone are sized to accommodate the circuit board mating tolerance distances. For example, the lengths of the contacts include the lengths required for mechanical mating and any designed contact wipe length plus the additional circuit board mating tolerance distance. The contacts have such length to accommodate the possible range of circuit board mating conditions. The additional length of the contacts is typically provided as an extension of the stub of the contact, which is the portion of the contact that extends past the mating point, to ensure that the contacts remain mated regardless of the circuit board positions. In high speed connectors, the stubs can significantly degrade the signal integrity performance of the connector. The electrical stub acts as a reflective element for energy that travels along the stub. When the energy travels back at certain combinations of signal wavelength (for example, frequency) and physical stub length, the stub can generate a null in transmitted energy at a specific frequency. When the stub is long enough, and the respective frequency low enough, the null is detrimental to the transmitted energy of the signal that reaches the receiver. 
     A need remains for electrical connectors of a communication system having an improved mating interface. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, a circuit board assembly is provided and includes a circuit board having a mounting surface. The circuit board has a mating edge. A circuit board assembly is provided and includes an electrical connector having a connector housing holding contacts in a contact array. The connector housing has a mating end and a cable end. The mating end is configured to be mated with a mating electrical connector in a mating direction. The electrical connector has cables terminated to the contacts and extends from the cable end. The connector housing has a mounting feature. A circuit board assembly is provided and includes a connector mount for locating the electrical connector relative to the circuit board. The connector mount has a bracket coupled to the mounting surface of the circuit board proximate to the mating edge. The electrical connector is movably coupled to the connector mount to move relative to the circuit board during mating with the mating electrical connector. The connector mount has a biasing member that is coupled to the bracket and coupled to the mounting feature of the electrical connector. The biasing member is compressible along a compression axis parallel to the mating direction to allow the electrical connector to float in the mating direction relative to the circuit board, wherein the electrical connector is movably coupled to the connector mount in a confined envelope in at least one floating direction perpendicular to the mating direction. 
     In another embodiment, a communication system is provided and includes a first circuit board assembly including a first circuit board, a first connector mount coupled to the first circuit board, and a first electrical connector coupled to the first connector mount. The first electrical connector has a first connector housing holding first contacts in a contact array. The first connector housing has a mating end and a cable end. The first electrical connector has cables terminated to the first contacts and extends from the cable end. The first connector housing has a first mounting feature. The first connector mount has a first bracket coupled to a mounting surface of the first circuit board proximate to the mating edge. The first electrical connector is movably coupled to the first connector mount to move relative to the first circuit board in a mating direction. The first connector mount has a first biasing member coupled to the first bracket and coupled to the first mounting feature of the first electrical connector. The first biasing member is compressible along a compression axis parallel to the mating direction to allow the first electrical connector to float in the mating direction relative to the first circuit board, wherein the first electrical connector is movably coupled to the first connector mount in a confined envelope in at least one floating direction perpendicular to the mating direction. A circuit board assembly is provided and includes a second circuit board assembly including a second circuit board and a second electrical connector coupled to the second circuit board. The second electrical connector has a second connector housing that holds second contacts in a contact array. The second connector housing has a mating end coupled to the mating end of the first connector housing along a mating axis parallel to the mating direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic view of a communication system in accordance with an exemplary embodiment. 
         FIG.  2    is a top perspective view of the communication system in accordance with an exemplary embodiment. 
         FIG.  3    is a rear perspective view of the communication system in accordance with an exemplary embodiment. 
         FIG.  4    is a perspective view of a portion of the communication system showing the mating interface of the first circuit board assembly in accordance with an exemplary embodiment. 
         FIG.  5    is a perspective view of a portion of the communication system showing the mating interface of the second circuit board assembly in accordance with an exemplary embodiment. 
         FIG.  6    is a front perspective view of the first electrical connector in accordance with an exemplary embodiment. 
         FIG.  7    is a rear perspective view of the first electrical connector in accordance with an exemplary embodiment. 
         FIG.  8    is a rear perspective view of a portion of the first electrical connector in accordance with an exemplary embodiment. 
         FIG.  9    is an enlarged rear perspective view of a portion of the first electrical connector in accordance with an exemplary embodiment. 
         FIG.  10    is a rear view of a portion of the first electrical connector in accordance with an exemplary embodiment. 
         FIG.  11    is a rear view of a portion of the first electrical connector in accordance with an exemplary embodiment. 
         FIG.  12    is a front perspective view of the bracket in accordance with an exemplary embodiment. 
         FIG.  13    is a front, partial sectional view of a portion of the first electrical connector in accordance with an exemplary embodiment 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG.  1    is a schematic view of a communication system  100  in accordance with an exemplary embodiment. The communication system  100  includes a first circuit board assembly  200  and a second circuit board assembly  300  electrically coupled together. In various embodiments, the communication system  100  may be a server or network switch. In other various embodiments, the communication system  100  may be a backplane system. The first circuit board assembly  200  and/or the second circuit board assembly  300  may be a backplane assembly. The first circuit board assembly  200  and/or the second circuit board assembly  300  may be a daughtercard assembly. The first circuit board assembly  200  and/or the second circuit board assembly  300  may be a motherboard assembly. 
     In an exemplary embodiment, the first circuit board assembly  200  and/or the second circuit board assembly  300  includes a compressible mating interface to take up mating tolerance for the communication system  100 . For example, the first circuit board assembly  200  and/or the second circuit board assembly  300  may include a spring-loaded connector configured to be compressed in the mating direction. In an exemplary embodiment, the first circuit board assembly  200  and/or the second circuit board assembly  300  is able to float in an X-direction (side-to-side), a Y-direction (top-to-bottom), and/or a Z-direction (front-to-rear) for proper alignment and mating. For example, the connector housing(s) may be movable to align with each other. 
     In an exemplary embodiment, the communication system  100  includes an equipment rack  110  used to hold the first circuit board assembly  200  and/or the second circuit board assembly  300 . The equipment rack  110  includes frame members  112  forming one or more chambers for the first circuit board assembly  200  and/or the second circuit board assembly  300 . In the illustrated embodiment, the equipment rack  110  includes a front chamber  120  configured to receive the first circuit board assembly  200  and a rear chamber  130  configured to receive the second circuit board assembly  300 . Optionally, multiple circuit board assemblies may be received in the front chamber  120  and/or the rear chamber  130 . The equipment rack  110  may be open at the front and/or the rear and/or the sides. Alternatively, the equipment rack  110  may include walls or panels (not shown) that close the chambers  120 ,  130  at the front and/or the rear and/or the sides. The equipment rack  110  may include horizontally oriented trays or platforms that divide the chambers  120 ,  130  into stacked sub-chambers each receiving a corresponding circuit board assembly. The equipment rack  110  may include vertically oriented divider walls that divide the chambers  120 ,  130  into adjacent sub-chambers each receive a corresponding circuit board assembly. 
     In an exemplary embodiment, the equipment rack  110  includes front guide elements  122  in the front chamber  120 . The front guide elements  122  are used to guide the first circuit board assembly  200  into the front chamber  120 . The front guide elements  122  may locate the first circuit board assembly  200  relative to the equipment rack  110 , such as for mating with the second circuit board assembly  200 . In an exemplary embodiment, the front guide elements  122  are rails or tracks having a slot or groove that receive the first circuit board assembly  200 . Other types of guide elements may be used in alternative embodiments, such as tabs, pins, posts, openings, sockets, and the like. 
     In an exemplary embodiment, the equipment rack  110  includes rear guide elements  132  in the rear chamber  130 . The rear guide elements  132  are used to guide the second circuit board assembly  300  into the rear chamber  130 . The rear guide elements  132  may locate the second circuit board assembly  300  relative to the equipment rack  110 , such as for mating with the first circuit board assembly  200 . In an exemplary embodiment, the rear guide elements  132  are rails or tracks having a slot or groove that receive the second circuit board assembly  300 . Other types of guide elements may be used in alternative embodiments, such as tabs, pins, posts, openings, sockets, and the like. 
     During assembly, the first circuit board assembly  200  is loaded into the front chamber  120  through the front end and the second circuit board assembly  300  is loaded into the rear chamber  130  through the rear end. The first and second circuit board assemblies  200 ,  300  are mated within the equipment rack  110 , such as at the center of the equipment rack  110 . One or both of the electrical connectors of the first and second circuit board assemblies  200 ,  300  are able to float (for example, move within a confined envelope) relative to the circuit board(s) to properly align and reduce the risk of damage to the components of the electrical connectors. The first and second circuit board assemblies  200 ,  300  slide into and out of the equipment rack  110 , such as along the guide elements  122 ,  132 . In the illustrated embodiment, the first and second circuit board assemblies  200 ,  300  are oriented perpendicular to each other. For example, the first circuit board assembly  200  is oriented vertically and the second circuit board assembly  300  is oriented horizontally, or vice versa. In other various embodiments, the first and second circuit board assemblies  200 ,  300  are oriented parallel to each other. For example, the first and second circuit board assemblies  200 ,  300  may both be oriented vertically. Alternatively, the first and second circuit board assemblies  200 ,  300  may both be oriented horizontally. 
     The first circuit board assembly  200  includes a first circuit board  210  and a first electrical connector  250  coupled to the first circuit board  210 . The first electrical connector  250  is configured to be mated with the second circuit board assembly  300 . Optionally, the first electrical connector  250  is a floating connector, wherein the first electrical connector  250  is movable relative to the first circuit board  210 . The first electrical connector  250  may be moved when mated with the second circuit board assembly  300 . For example, the first electrical connector  250  may have a compressible mating interface. Alternatively, the first electrical connector  250  may be a fixed connector, wherein the first electrical connector  250  is fixed relative to the first circuit board  210  and does not move relative to the first circuit board  210  when mated with the second circuit board assembly  300 . 
     The second circuit board assembly  300  includes a second circuit board  310  and a second electrical connector  350  coupled to the second circuit board  310 . The second electrical connector  350  is configured to be mated with the first electrical connector  250  of the first circuit board assembly  200 . Optionally, the second electrical connector  350  may be a floating connector, wherein the second electrical connector  350  is movable relative to the second circuit board  310 . The second electrical connector  350  may be moved when mated with the second circuit board assembly  300 . For example, the second electrical connector  350  may have a compressible mating interface. Alternatively, the second electrical connector  350  may be a fixed connector, wherein the second electrical connector  350  is fixed relative to the second circuit board  310  and does not move relative to the second circuit board  310  when mated with the first electrical connector  250 . 
       FIG.  2    is a top perspective view of the communication system  100  in accordance with an exemplary embodiment.  FIG.  3    is a rear perspective view of the communication system  100  in accordance with an exemplary embodiment.  FIG.  2    shows the first electrical connector  250  as a cable connector and the second electrical connector  350  as a board connector. The first electrical connector  250  is a floating connector and the second electrical connector  350  is a fixed connector.  FIG.  3    shows the first electrical connector  250  as a cable connector and the second electrical connector  350  as a cable connector. The first electrical connector  250  is a floating connector and the second electrical connector  350  is a fixed connector. In alternative embodiments, the second electrical connector  350  may be a floating connector. 
     In the illustrated embodiments, the communication system  100  includes multiple front circuit board assemblies  200  and multiple rear circuit board assemblies  300 ; however, the communication system  100  may include a single front circuit board assembly  200  and/or a single rear circuit board assembly  300 . In the illustrated embodiment, the circuit board  210  has a single electrical connector  250  and the circuit board  310  has a single electrical connector  350 ; however, the circuit board  210  may include multiple electrical connectors  250  and/or the circuit board  310  may include multiple electrical connectors  350 . 
     The first circuit board  210  includes a mating edge  212  at a front of the first circuit board  210  and side edges  214 ,  216  extending between the mating edge  212  and a rear edge  218 . The first circuit board  210  is rectangular in the illustrated embodiment. The first circuit board  210  may have other shapes in alternative embodiments. The circuit board  210  includes first and second surfaces  220 ,  222  (for example, upper and lower surfaces). The first electrical connector  250  is mounted to the first surface  220  of the circuit board  210  at a mounting area  224 . Optionally, the mounting area  224  may be located proximate to the mating edge  212 . One or more electrical connectors may additionally or alternatively be located at the second surface  222 . 
     In an exemplary embodiment, the first circuit board  210  includes one or more electrical components  226  coupled to the first circuit board  210 . The electrical components  226  may be chips, integrated circuits, processors, memory modules, electrical connectors or other components. The electrical components  226  may be electrically connected to the circuit board  210 , such as through traces, pads, vias or other circuits. In an exemplary embodiment, the electrical components  226  are electrically connected to the first electrical connector  250 , such as through the first circuit board  210  or by direct connection through the cables. 
     The first circuit board  210  includes one or more board guide features  230  for locating the circuit board  210  in the equipment rack  110  (shown in  FIG.  1   ). The board guide features  230  are configured to be coupled to the corresponding guide elements  122  (shown in  FIG.  1   ). In the illustrated embodiment, the board guide features  230  are defined by the edges of the circuit board  210  along the sides  214 ,  216 , which are configured to slide into grooves of the track defining the guide elements  122 . Other types of guide features may be used in alternative embodiments, such as rails, slots tabs, pins, and the like. 
     In an exemplary embodiment, the first circuit board assembly  200  includes latching features  232  at the rear edge  218 . The latching features  232  are used to secure the first circuit board assembly  200  to the equipment rack  110 . The latching features  232  may be used to press the circuit board  210  forward (toward the second circuit board  310 ) during mating or may be used to pull the circuit board  210  rearward during unmating. 
     In an exemplary embodiment, the first circuit board assembly  200  includes a first connector mount  240 . The first connector mount  240  includes a bracket  242  and one or more biasing members  244  coupled to the bracket  242  and the electrical connector  250 . The electrical connector  250  is movably coupled to the connector mount  240 . For example, the electrical connector  250  may be moved in the X-direction (side-to-side), the Y-direction (top-to-bottom), and/or the Z-direction (front-to-rear). The biasing members  244  forward bias the electrical connector  250  (in the Z-direction) for mating with the second electrical connector  350 . In an exemplary embodiment, the biasing members  244  include springs, such as coil springs. Other types of biasing members may be used in alternative embodiments, such as compressible foam members. The biasing members  244  may provide a flexible connection between the electrical connector  250  and the connector mount  240 . 
     The biasing members  244  allow the electrical connector  250  to move relative to the circuit board  210 , such as during mating with the second electrical connector  350 . The biasing members  244  provide compressive forces for maintaining mechanical and electrical connection between the first and second electrical connectors  250 ,  350 . The biasing members  244  accommodate the mating tolerances between the circuit board assemblies  200 ,  300  within the equipment rack  110 . For example, the circuit board  210  may have a positional range within the equipment rack  110  (for example, position of the mating edge  212  within the equipment rack  110  may vary by approximately 1.5 mm). The biasing members  244  may accommodate some or all of the mating dimensional tolerance distance (for example, approximately 1.5 mm) of the circuit board  210  in the equipment rack  110 . 
     The second circuit board  310  includes a mating edge  312  at a front of the second circuit board  310  and side edges  314 ,  316  extending between the mating edge  312  and a rear edge  318 . The mating edge  312  faces the mating edge  212  of the first circuit board  210 . The circuit board  310  includes first and second surfaces  320 ,  322  (for example, left side and right side). The second electrical connector  350  is mounted to the first surface  320  of the circuit board  310  at a mounting area  324 . Optionally, the mounting area  324  may be located proximate to the mating edge  312 . One or more electrical connectors may additionally or alternatively be located at the second surface  322 . 
     In an exemplary embodiment, the second circuit board  310  includes one or more electrical components  326  coupled to the second circuit board  310 . The electrical components  326  may be chips, integrated circuits, processors, memory modules, electrical connectors or other components. The electrical components  326  may be electrically connected to the circuit board  310 , such as through traces, pads, vias or other circuits. In an exemplary embodiment, the electrical components  326  are electrically connected to the second electrical connector  350 , such as through the second circuit board  310  or by direct connection through cables. 
     The second circuit board  310  includes one or more board guide features  330  for locating the circuit board  310  in the equipment rack  110  (shown in  FIG.  1   ). The board guide features  330  are configured to be coupled to the corresponding guide elements  132  (shown in  FIG.  1   ). In the illustrated embodiment, the board guide features  330  are defined by the edges of the circuit board  310  along the sides  314 ,  316 , which are configured to slide into grooves of the track defining the guide elements  132 . Other types of guide features may be used in alternative embodiments, such as rails, slots tabs, pins, and the like. 
     In an exemplary embodiment, the second circuit board assembly  300  includes latching features  332  at the rear edge  318 . The latching features  332  are used to secure the second circuit board assembly  300  to the equipment rack  110 . The latching features  332  may be used to press the circuit board  310  forward (toward the first circuit board  210 ) during mating or may be used to pull the circuit board  310  rearward during unmating. 
       FIG.  4    is a perspective view of a portion of the communication system  100  showing the mating interface of the first circuit board assembly  200  in accordance with an exemplary embodiment.  FIG.  5    is a perspective view of a portion of the communication system  100  showing the mating interface of the second circuit board assembly  300  in accordance with an exemplary embodiment. The first circuit board assembly  200  has a compressible mating interface in the illustrated embodiment (for example, the first electrical connector  250  is movable relative to the first circuit board  210 ). The second circuit board assembly  300  has a fixed mating interface in the illustrated embodiment (for example, the second electrical connector  350  is fixed relative to the second circuit board  310 ). 
     The first electrical connector  250  includes a connector housing  252  holding first contacts  254  ( FIG.  4   ) in a contact array. In various embodiments, the contacts  254  may be arranged together in first contact modules  256 , also known as chicklets, which may be overmolded leadframes. The connector housing  252  includes a mating end  258  configured to be mated with the second electrical connector  350 . The mating end  258  is at the front of the connector housing  252 . The contacts  254  are exposed at the mating end  258  for mating with corresponding contacts of the second electrical connector  350 . 
     In the illustrated embodiment, the first electrical connector  250  is a cable connector having a plurality of first cables  260  extending from the connector housing  252 . The connector housing  252  includes a cable end  262 . The cables  260  extend from the cable end  262 . In the illustrated embodiment, the cable end  262  is opposite the mating end  258 ; however, other orientations are possible in alternative embodiments, such as being a right-angle connector with the cable end  262  perpendicular to the mating end  258 . The cables  260  may be individual cables  260 , such as coaxial cables or twin axial cables. In other embodiments, the cables  260  may be flat, flexible cables, such as flex circuits. The cables  260  are electrically connected to corresponding contacts  254 . The cables  260  are flexible to allow movement of the first electrical connector  250  relative to the first circuit board  210 . 
     The first electrical connector  250  is configured to be mated with the second electrical connector  350  in a mating direction (along a mating axis  264 ). The mating end  258  may be perpendicular to the mating axis  264 . In an exemplary embodiment, the first electrical connector  250  is movable in a direction parallel to the mating axis  264  (Z-direction). For example, the first electrical connector  250  may be pressed rearward during mating. In an exemplary embodiment, the first electrical connector  250  is movable in a direction perpendicular to the mating axis  264  (for example, side-to-side and/or top-to-bottom). 
     In an exemplary embodiment, the connector housing  252  includes one or more mounting features  266 . The mounting features  266  may be tabs or ears extending from one or more sides of the connector housing  252 . The mounting features  266  are coupled to the connector mount  240 , such as to the bracket  242 . In an exemplary embodiment, the biasing members  244  are coupled to the mounting features  266 . The biasing members  244  may press the mounting features  266  forward against the bracket  242 . The bracket  242  operates as a forward stop for the connector housing  252 . The bracket  242  positions the first electrical connector  250  for mating with the second electrical connector  350 . The connector housing  252  may be movable relative to the bracket  242 , such as sliding side-to-side or up-and-down on the bracket  242 . 
     The contacts  254  are provided at the mating end  258  for mating with the second electrical connector  350 . In an exemplary embodiment, the contacts  254  are stamped and formed contacts. The contacts  254  have a metal body extending between a mating end  268  and a terminating end (not shown) opposite the mating end  268 . In an exemplary embodiment, conductors of the cables  260  are terminated to the terminating end of the corresponding contacts  254 . For example, the terminating end may include a solder pad, a crimp barrel, an insulation displacement termination, or another type of electrical termination. In alternative embodiments, rather than being terminated to the cables  260 , the terminating ends of the contacts  254  may be terminated directly to the circuit board  210 , such as being soldered or press fit into plated vias of the circuit board  210 . In such embodiment, the first electrical connector  250  may be fixed relative to the circuit board  210 . 
     The mating end  268  of each contact  254  includes a mating interface configured to be electrically connected to the corresponding contact of the second electrical connector  350 . The mating ends  268  may be spring beams, pins, sockets, pads, and the like. In an exemplary embodiment, the mating end  268  has a short electrical length downstream of the mating interface, leading to a short electrical stub. Because the first electrical connector  250  is able to float relative to the first circuit board  210 , the mating ends  268  of the contacts  254  are very short as the mating ends  268  do not need to accommodate the tolerance of the circuit board mating as such tolerance is accommodated by the spring loaded, floating movement of the electrical connector  250  (for example, as provided by the biasing members  244 ). The length of the stub at the mating end  268  may be short enough to just accommodate mechanical mating plus any contact wipe, but does not need to accommodate any circuit board mating tolerance. 
     The second electrical connector  350  includes a connector housing  352  holding second contacts  354  ( FIG.  5   ) in a contact array. In various embodiments, the contacts  354  may be arranged together in second contact modules  356 , also known as chicklets, which may be overmolded leadframes. The connector housing  352  includes a mating end  358  configured to be mated with the first electrical connector  250 . The mating end  358  is at the front of the connector housing  352  (facing the mating end  258  of the first electrical connector  250 ). The second contacts  354  are exposed at the mating end  358  for mating with the first contacts  254 . 
     In the illustrated embodiment, the second electrical connector  350  is a board connector configured to be mounted directly to the second circuit board  310 . The connector housing  352  includes a mounting end  364  mounted to the second circuit board  310 . In the illustrated embodiment, the second electrical connector  350  is a right-angle connector having the mounting end  364  perpendicular to the mating end  358 ; however, other orientations are possible in alternative embodiments. The connector housing  352  may include mounting features for mounting the connector housing  352  to the circuit board  310 , such as mounting lugs that receive threaded fasteners, press tabs, solder tabs, and the like. Alternatively, the contacts  354  may be used to mount the second electrical connector  350  to the circuit board  310 , such as using press fit pins. 
     The second electrical connector  350  is configured to be mated with the first electrical connector  250  in the mating direction along the mating axis  264 . The first electrical connector  350  may be pressed rearward during mating as the second circuit board assembly  300  is loaded into the equipment rack  110 . The movement of the first electrical connector  350  allows the contacts  254 ,  354  to be relatively short as the contacts  254 ,  354  do not need to accommodate for the circuit board mating tolerance, which may be approximately 1.5 mm, meaning that the first contacts  254  and/or the second contacts  354  may be shortened, such as by approximately 1.5 mm compared to other systems. 
     The contacts  354  are provided at the mating end  358  for mating with the second electrical connector  350 . In an exemplary embodiment, the contacts  354  are stamped and formed contacts. The contacts  354  have a metal body  370  extending between a mating end  372  and a terminating end (not shown) opposite the mating end  372 . The contacts  354  have mating interfaces  380  at the mating ends  372 . In an exemplary embodiment, the terminating ends of the contacts  354  may be terminated directly to the circuit board  310 , such as being soldered or press-fit into plated vias of the circuit board  310 . Alternatively, the contacts  354  may be terminated to cables rather than directly to the circuit board  310 . 
     The mating end  372  of each second contact  354  includes a mating interface configured to be electrically connected to the first contact  254 . The mating ends  372  may include spring beams, pads, pins, sockets, and the like. In an exemplary embodiment, the mating end  372  has a short electrical length downstream of the mating interface, leading to a short electrical stub. Because the first electrical connector  250  is able to float (press rearward) when mated with the second electrical connector  350 , the mating ends  372  of the contacts  354  are very short as the mating ends  372  do not need to accommodate the tolerance of the circuit board mating as such tolerance is accommodated by the spring loaded, floating movement of the first electrical connector  250 . The length of the stub at the mating end  372  may be short enough to just accommodate mechanical mating plus any contact wipe, but does not need to accommodate any circuit board mating tolerance. 
     The floating mounting system provided by the connector mount  240  and the biasing members  244  for the first electrical connector  250  (and similarly may be provided for the second electrical connector  350 ) absorbs the circuit board mating tolerance (for example, absorbs 1.5 mm mating tolerance or more) and may allow alignment of the first and second electrical connectors  250 ,  350 . The floating mounting system eliminates the need for additional alignment features, such as alignment modules mounted to the circuit boards adjacent the electrical connectors  250 ,  350 , which add cost and occupy valuable space on the circuit boards. The floating mounting system eliminates the need for the contact interface to be able to absorb the large rack mating tolerances allowing shorting contacts. The stubs at the ends of the contacts  254  and/or  354  may be shortened (for example, less than 1.0 mm), which improves the performance of the communication system  100  by improving the signal integrity along the signal paths. The performance, particularly at high speeds (for example, above 100Gbps and more particularly, above 200Gbps) is improved compared to contacts having long electrical stubs. 
       FIG.  6    is a front perspective view of the first electrical connector  250  in accordance with an exemplary embodiment.  FIG.  7    is a rear perspective view of the first electrical connector  250  in accordance with an exemplary embodiment.  FIGS.  6  and  7    illustrate the connector housing  252  coupled to the connector mount  240 . 
     The bracket  242  of the connector mount  240  includes a mounting plate  270  and mounting tabs  272  extending from the mounting plate  270 . The mounting plate  270  is configured to be mounted to the first circuit board  210  (shown in  FIG.  3   ). In an exemplary embodiment, the mounting plate  270  is oriented horizontally. The mounting tabs  272  extends perpendicular to the mounting plate  270 . For example, the mounting tabs  272  extend outward (i.e., vertically) from the mounting plate  270 . The mounting features  266  of the connector housing  252  are configured to be mounted to the mounting tabs  272 . For example, the connector housing  252  is located in the space between the mounting tabs  272  and the mounting features  266  are located behind the mounting tabs  272 . The biasing members  244  coupled to the mounting features  266  to the mounting tabs  272 . The mounting tabs  272  stop forward movement of the mounting tabs  272  to position the connector housing  252  relative to the bracket  242 . In an exemplary embodiment, the mounting tabs  272  include bracket openings  274  (shown in  FIG.  12   ) therethrough that receive portions of the biasing members  244 . In an exemplary embodiment, the spacing between the mounting tabs  272  is larger than the width of the connector housing  252  such that the clearance gaps  276  are located between the mounting tabs  272  and the connector housing  252 . The clearance gaps  276  allow the connector housing  252  to move between the mounting tabs  272 . For example, the connector housing  252  is able to move side-to-side between the mounting tabs  272 . In various embodiments, clearance gaps  278  may be located between the mounting features  266  and the mounting plate  270 . The clearance gaps  278  allow the connector housing  252  to move relative to the mounting plate  270  (for example, top-to-bottom movement). 
     The connector housing  252  is a dielectric housing, such as a plastic housing. The connector housing  252  holds the contacts  254 . For example, the connector housing  252  may hold the contact modules  256 . The connector housing  252  includes a front  280  and a rear  281 . The connector housing  252  includes a first side  282  and a second side  283 . The connector housing  252  includes a top  284  and the bottom  285 . In the illustrated embodiment, the connector housing  252  is generally rectangular. However, the connector housing  252  may have other shapes in alternative embodiments. In the illustrated embodiment, the mounting features  266  extend outward from the first and second sides  282 ,  283 . The mounting features  266  may be provided at other locations in alternative embodiments. In an exemplary embodiment, the front  280  defines the mating end  258 . In the illustrated embodiment, the bottom  285  is configured to face the circuit board  210 . The bottom  285  faces the mounting plate  270 . For example, the mounting plate  270  may be located between the bottom  285  and the circuit board  210 . 
     In an exemplary embodiment, the mounting features  266  include openings  286  (shown in  FIG.  8   ) therethrough. The openings  286  are configured to receive portions of the biasing members  244 . For example, the biasing members  244  may pass through the openings  286 . The openings  286  may be aligned with the bracket openings  274  to allow the biasing members  244  to pass through the mounting tabs  272  and the mounting features  266 . Optionally, the openings  286  may be approximately centered on the mounting features  266 . 
     In an exemplary embodiment, the biasing members  244  each include a spring member  290  and a spring pin  291  used to couple the spring member  290  to the mounting feature  266  and/or the mounting tab  272 . The spring pin  291  may be a threaded fastener, such as a bolt, in various embodiments. The spring pin  291  includes a head  292  at a front of the spring pin  291 . In an exemplary embodiment, a securing nut  293  is coupled to the distal end of the spring pin  291 . For example, the securing nut  293  may be threadably coupled to the end of the spring pin  291 . Washers  294  may be held on the spring pin  291 , such as at the head  292  and/or at the securing nut  293  and/or at other locations, such as at the mounting feature  266  and/or the mounting tab  272 . The spring pin  291  passes through the mounting feature  266  and the mounting tab  272 . The spring pin  291  passes through the spring member  290 . For example, the spring member  290  may be a coil spring having a central bore that receives the spring pin  291 . The spring member  290  is located between the securing nut  293  and the mounting feature  266 . 
     The spring member  290  presses forward against the rear of the mounting feature  266  to forward bias the electrical connector  250  for mating with the second electrical connector  350  (shown in  FIG.  4   ). The spring member  290  is compressible along a compression axis  295  to allow front-to-rear movement. The compression axis  295  is parallel to the mating direction (for example, Z-direction). The connector housing  252  is movable relative to the bracket  242  along the compression axis  295  when the spring member  290  is compressed, such as during mating with the second electrical connector  350 . 
     In an exemplary embodiment, the biasing member  244  is movable relative to the connector housing  252  and/or relative to the bracket  242  and at least one floating direction perpendicular to the mating direction. For example, the biasing member  244  may be loose fit through the connector housing  252  and/or the bracket  242  to allow the floating movement, such as side-to-side and/or top-to-bottom. In various embodiments, the spring pin  291  may move up and down and/or left and right within the opening  286  through the mounting feature  266  to allow the floating movement or the mounting feature  266  may move up and down and/or left and right on the spring pin  291  to allow the floating movement. In various embodiments, the spring pin  291  may move up and down and/or left and right within the bracket opening  274  through the mounting tab  272  to allow the floating movement. 
       FIG.  8    is a rear perspective view of a portion of the first electrical connector  250  in accordance with an exemplary embodiment.  FIG.  9    is an enlarged rear perspective view of a portion of the first electrical connector  250  in accordance with an exemplary embodiment.  FIGS.  8  and  9    illustrate the connector housing  252  coupled to the bracket  242 . The spring pins  291  are illustrated in  FIGS.  8  and  9   . The spring pins  291  pass through the openings  286  and the mounting features  266 . 
     In an exemplary embodiment, the openings  286  are oversized relative to the spring pins  291 . For example, the openings  286  have larger diameters than the diameters of the spring pins  291 . Clearance gaps  287  are provided between the mounting features  266  and the spring pins  291 . The clearance gaps  287  provide a space of relative movement between the mounting features  266  and the spring pins  291 . The clearance gaps  287  define confined envelopes for the floating movement of the connector housing  252 . For example, the connector housing  252  may move upward or downward until the mounting features  266  bottom out against the spring pins  291 . The connector housing  252  may move right or left until the mounting features  266  bottom out against the spring pins  291 . Optionally, the size and shape of the openings  286  may accommodate movement in all directions. Alternatively, the size and shape of the openings  286  may accommodate movement in a limited number of directions (for example, only up and down or only left and right). In various embodiments, the size and shape of the openings  286  may accommodate a greater range of motion in some directions and a more limited range of motion in other directions. 
       FIG.  10    is a rear view of a portion of the first electrical connector  250  in accordance with an exemplary embodiment.  FIG.  10    shows the spring pin  291  within the opening  286  of the mounting feature  266 . In the illustrated embodiment, the spring pin  291  is cylindrical the opening  286  is cylindrical having a greater diameter than the diameter of the spring pin  291 . The oversized diameter of the opening  286  forms the clearance gap  287 . The size of the clearance gap  287  is based on the oversizing of the opening  286  relative to the spring pin  291 . In various embodiments, the spring pin  291  may be centered in the opening  286  providing equal clearance gaps  287  circumferentially around the spring pin  291  allowing movement in all directions. Alternatively, the spring pin  291  may sit off centered within the opening  286  allowing greater movement in some directions than other directions. 
       FIG.  11    is a rear view of a portion of the first electrical connector  250  in accordance with an exemplary embodiment.  FIG.  11    shows the spring pin  291  within the opening  286  of the mounting feature  266  in the illustrated embodiment, the opening  286  is oval-shaped having a larger dimension in the vertical direction and a smaller dimension in the horizontal direction. The horizontal dimension may be approximately equal to the diameter of the spring pin  291  thus restricting right to left movement. However, the oval-shaped of the opening  286  allows vertical movement of the mounting feature  266  relative to the spring pin  291 . The opening  286  may have other shapes in alternative embodiments to allow controlled, floating movement of the mounting feature  266  relative to the spring pin  291 . 
       FIG.  12    is a front perspective view of the bracket  242  in accordance with an exemplary embodiment. The bracket  242  includes the mounting plate  270  and the mounting tabs  272 . The mounting tabs  272  include the bracket openings  274 . In the illustrated embodiment, the bracket openings  274  are cylindrical. However, the bracket openings  274  may have other shapes in alternative embodiments. For example, the bracket openings  274  may be oval-shaped. The bracket openings  274  may be sized relative to the spring pins  291  (shown in  FIG.  13   ). In various embodiments, the bracket openings  274  may have diameters approximately equal to the diameters of the spring pins  291  such that the spring pins  291  are fixed in position relative to the mounting tabs  272 . Alternatively, the bracket openings  274  may be enlarged or oversized relative to the diameters of the spring pins  291  such that the spring pins  291  are allowed a limited amount of floating movement within the bracket openings  274 . The mounting tabs  272  confine the floating movement within a confined envelope defined by the size and shape of the bracket openings  274 . 
       FIG.  13    is a front, partial sectional view of a portion of the first electrical connector  250  in accordance with an exemplary embodiment.  FIG.  13    shows the connector housing  252  coupled to the bracket  242 . Portions of the biasing members  244  are shown in  FIG.  13   . For example, the spring pins  291  are shown in cross-section cut off at the front surface of the mounting tabs  272 . 
     In the illustrated embodiment, the bracket openings  274  are oversized relative to the spring pins  291 . The spring pins  291  extend forward from the mounting features  266  of the connector housing  252  through the bracket openings  274 . In an exemplary embodiment, the spring pins  291  are tightly held in the mounting features  266 . For example, the openings  286  through the mounting features  266  may have diameters equal to the diameters of the spring pins  291  such that the spring pins  291  to not move relative to the mounting features  266 . The spring pins  291  extend through the bracket openings  274 . The bracket openings  274  are oversized relative to the spring pins  291  forming clearance gaps  296  between the spring pins  291  and the mounting tabs  272 . The clearance gaps  296  allow the spring pins  291  to move within the bracket openings  274 . As such, the mounting features  266 , and the connector housing  252 , are able to move relative to the mounting tabs  272 . The bracket openings  274  form a confined envelope to limit and control the amount of floating movement of the spring pins  291  relative to the mounting tabs  272 . The size and shapes of the bracket openings  274  control the floating movement direction(s). For example, the bracket openings  274  may be oversized to allow floating movement in all directions. Alternatively, the bracket openings  274  may be oversized to allow floating movement in only some directions and confined movement in other directions. 
     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 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 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(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.