Abstract:
The invention pertains to a compact connector that accommodates a standard cable connector. By reducing the number of components at the interface, the invention allows a small form factor module to accommodate a cable connector that has thus been accommodated only by modules having larger dimensions. The device of the invention includes an electrically conductive lead protruding from a first outer surface of a connector housing and a shell disengageably coupled to the connector housing so as to form a cavity with the lead positioned therein, wherein the first outer surface forms an inner wall of the cavity. The invention also pertains to a module containing electrical components, including a lead, and a shell designed to hold a cable connector in contact with the lead. If the shell is made of a material that blocks electromagnetic radiation, the compact connector also serves as an EMI shield.

Description:
BACKGROUND  
       [0001]     The invention relates generally to electronic modules and particularly to electronic transceiver modules of small form factor.  
         [0002]     Communication systems are widely employed for a variety of purposes ranging from a basic transmission line in public communication channel to a short-distance network such as a LAN (local area network). These systems include various electronic devices that are interconnected with signal carrying media, such as fiber optic cables or electronic cables. Often, at the interface of a cable and a device is one or more transceivers that receive signals from the cable and forward them to the host device, or receive signals from the host device and forward them to the cable.  
         [0003]     A transceiver, unlike a simple connector, serves as an interface converter. For example, fiber optic transceivers convert high-speed electrical signals and convert them to high-speed optical signals. An electronic transceiver that can function as a pass-through, an amplifier, or a reformatter of the electronic signal in such a way as to allow it to transmit over longer distances (serial to parallel conversion) also exist.  
         [0004]     Transceivers are typically designed to be electrically and/or optically coupled to a host device and to a network. Typically, transceivers are packaged in the form of a module that has a host device end and a network end. At the host device end, the transceiver module may be mounted on a motherboard of a host device and/or mechanically plugged into a panel that is coupled to the host device. At the network end, the transceiver module is mechanically coupled with a cable connector. There are a number of different connector standards that have been used in the past and have evolved into industry standards. These connector standards include but are not limited to MT-RJ, LC, and SC connectors for optical cables, and RJ-45, RJ-11 and BNC for electrical cables. RJ-45 connectors, which are commonly used with Category 5 cables, are the generally preferred electronic cable/connector systems in most LANs. For pluggable modules, the panel of the host device usually has one or more openings that can accommodate standard sized transceiver modules configured with one of these standard connection interfaces.  
         [0005]     Standard modules (e.g., MSA standards) include GBIC modules and, more recently, Small Form Factor Pluggable (SFP) modules, both of which are well known in the industry. SFP modules are becoming increasingly preferred over GBIC modules for their smaller size. As communication systems evolve to require more bandwidth, higher module density is needed at the host device panel, calling for smaller modules. Currently, however, use of SFP modules are limited by the fact that they are not large enough to accommodate many standard cable connectors. Since GBIC modules can accommodate larger cable connectors, e.g., an RJ-45 connector jack, the industry is often forced to use GBIC modules even if SFP modules would be more advantageous. Clearly, an SFP module that can accommodate standard cable connectors is needed. However, because the size of a standard cable connector such as an RJ-45 connector is large relative to the small dimensions of SFP, designing an SFP module that can accommodate an RJ-45 connector jack has been challenging.  
         [0006]      FIG. 1  depicts a conventional connector jack  10  that is used to mechanically connect a larger module (e.g., a GBIC module) to a cable connector  11 . The connector jack  10  includes a set of electrically conductive leads  14  that are partially enclosed in the jack&#39;s plastic housing  16  such that the ends are exposed. A first exposed region  12  of the leads are designed to be coupled to a printed circuit board (not shown) while a second exposed region  14  of the connectors are designed to be coupled with the cable connector  11 . The first exposed region  12  may be located on any part of the plastic housing  16  as is convenient for coupling to a printed circuit board. The second exposed region  14  are positioned inside a cavity  18  of the plastic housing  16  such that when the cable connector  11  is inserted into the cavity  18 , connection(s) will be established between the printed circuit board and the cable. The cavity  18  is sized and shaped to accommodate a standard cable connector, such as an RJ-45 connector used with a CAT-5 cable. The sidewalls of the plastic housing  16  have to be rigid enough to hold the cable connector  11  in place, and the rigidity requires that the cavity  18  be enclosed by walls of a certain minimum thickness x. Naturally, the size and shape of the plastic housing  16  is dictated largely by the dimensions of the cable connector  11 .  
         [0007]      FIG. 2  depicts a manner in which the conventional connector jack  10  and the printed circuit board are assembled into a conventional GBIC module  20  by being placed inside a metal shell. The connector jack  10  is coupled to a printed circuit board  22  by any of the well-known and suitable means (e.g., a ribbon connector  24 ), and this connector-board combination is enclosed by a lower shell  26  and an upper shell  28 . The lower shell  26  and the upper shell  28 , which are made of a material that shields electromagnetic radiation, are attached firmly to each other with screws  29 . The metal shells  26 ,  28  protect the electrical components of the transceiver  20  and shield electromagnetic radiation. A connector cover  26   a  of the lower module shell  26  and a connector cover  28   a  of the upper module shell  28  are designed to surround the connector jack  10 , further shielding electromagnetic radiation.  
         [0008]      FIG. 3  depicts the GBIC module  20  that is assembled in the manner shown in  FIG. 2 . The assembled GBIC module  20  is substantially encapsulated with the metal shield  26 ,  28  except for the cavity  18  at the network end and an opening (not shown) at the host end  29 . As described above, the GBIC module  20  uses separate mechanisms for holding the cable connector (i.e., plastic housing  16 ) and for shielding electromagnetic radiation (i.e., the metal shell  26 ,  28 ). As both of these functions are usually needed and the dimensions of the plastic housing  16  alone are larger than the dimensions of the entire connector end of an SFP module as dictated by MSA, today&#39;s SFP modules are not compatible with standard RJ-45 cable connectors. However, as stated above, there is an increasing need for an SFP module that can accommodate an RJ-45 cable connector.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     The invention pertains to a compact electrical interface device. The electrical connector of the invention includes an electrically conductive lead protruding from a first outer surface of a plastic housing and a shell disengageably coupled to the plastic housing so as to form a cavity with the lead positioned therein, wherein the first outer surface forms an inner wall of the cavity. The invention also pertains to a module containing electrical components, including a lead, and a shell designed to hold a cable connector in contact with the lead. The shell may be made of metal, in which case the shell serves both the function of a connector and the function of an electromagnetic radiation shield. Another aspect of the invention is a method of connecting electrical components to a network by partially enclosing an electrical lead with a shell and shaping the shell to hold a cable connector in contact with the electrical lead. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a prior art connector that is used to mechanically connect a module to a cable connector;  
         [0011]      FIG. 2  is an exploded perspective view showing a method of assembling a module using the prior art connector of  FIG. 1 ;  
         [0012]      FIG. 3  is a perspective view showing a module assembled in the manner shown in  FIG. 2 ;  
         [0013]      FIG. 4  is a perspective view of a compact connector in accordance with the invention;  
         [0014]      FIG. 5  is an exploded perspective view showing a method of assembling a module using the compact connector of  FIG. 4 ;  
         [0015]      FIG. 6  is a perspective view of a module assembled in the manner shown in  FIG. 5 ;  
         [0016]      FIG. 7A  is a partial perspective view of the module of  FIG. 6  including a latching mechanism wherein the module is in an operational mode;  
         [0017]      FIG. 7B  is a partial perspective view of the module of  FIG. 6  including a latching mechanism wherein the module is in a release mode;  
         [0018]      FIG. 8  is a top view of the compact connector used in the module of  FIG. 7A  and  FIG. 7B ;  
         [0019]      FIG. 9  is an end view of the module of  FIG. 7A  from the network end;  
         [0020]      FIG. 10  is a perspective view of the module of  FIG. 9  from another angle; and  
         [0021]      FIG. 11  is a perspective view of a fully assembled module including the latching mechanism and the compact connector in accordance with the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]     The present invention is directed to a transceiver module and it will be described in that context. However, it will be appreciated that the teachings of the present invention are applicable to any electrical device with a removable connection.  
         [0023]      FIG. 4  depicts an isometric view of a connector  50  in accordance with the invention. The connector  50  includes electrical leads  52  that are partially enclosed by a plastic housing  54 . The plastic housing  54  includes six outer surfaces: a first outer surface  54   a  from which the electrical leads  52  protrude; a second outer surface  54   b  on the side that is opposite the first outer surface  54   a;  and a third, fourth, fifth, and sixth outer surfaces  54   c,    54   d,    54   e,  and  54   f  located in planes that are substantially orthogonal to the plane of the first outer surface  54   a.  The portion of the plastic housing  54  that is near the third outer surface  54   c  preferably extends to form an extension  56 , which contacts a region  58  of the electrical leads  52  and provides support to the leads  52 . The electrical leads  52  are positioned so that they can form and maintain contact with the electrically conductive portions of a cable connector. Unlike the conventional connector jack  10  (see  FIG. 1 ), the leads  52  of the connector  50  are not integrated with a structure that holds a cable connector in place.  
         [0024]     An “outer surface,” as used herein, refers to a surface that forms a part of the outline of the plastic housing  54 . A “plastic housing,” as used herein, is a type of enclosure that is made of an electrically nonconductive material including but not limited to plastic. A “cable connector,” as used herein, is any type of standard or non-standard component that may be used to connect the leads  52  to a removable cable connector, such as an RJ-45 connector.  
         [0025]     A transitional section  60  is preferably located between the third outer surface  54   c  and the extension  56 . The transitional section  60  is sloped so that the extension  56  is separated from the plane of the sixth outer surface  54   f  by a different distance than the third outer surface  54   c.  When the connector  50  is assembled into a module, only the extension  56  contacts the module shell (as shown in  FIG. 5 ). Since the outer surface  54   c  and the transition section  60  do not contact the module shell, a cavity is formed by the third outer surface  54   c,  the transition section  60 , and the module shell that encloses the connector  50 . This cavity is necessary for accommodating an optional bail which is described below. In the embodiment shown in  FIG. 4 , the electrical leads  52  are positioned so that they are at an angle to both the first outer surface  54   a  and the extension  56 . The extension prevents the leads  52  from contacting the module shell that will be positioned near the extension  56 .  
         [0026]     In the embodiment of  FIG. 4 , the second outer surface  54   b  includes portions of the electrical leads  52  that are coupled to a printed circuit board (not shown). Although the embodiment shows a ribbon connector  62  as the means for electrically connecting the leads  52  to a printed circuit board, the invention is not so limited. A person of ordinary skill in the art would appreciate that the invention is not limited to the exact embodiment shown in  FIG. 4 . For example, the leads  52  are not limited to protruding from the first and second outer surfaces  54   a  and  54   b,  respectively, of the connector housing  50 , and the shape and the position of the extension  56  may be varied.  
         [0027]      FIG. 5  depicts the manner in which the connector  50  is assembled into a module in accordance with the invention. The connector  50  is electrically coupled to a printed circuit board  70  and placed between a first partial shell  80  and a second partial shell  90 . The first partial shell  80  has a connector cover  82  that is designed to partially enclose the connector  50 . The first partial shell  80  and the second partial shell  90  are made of an EMI-shielding material, such as metal. When the first partial shell  80  and the second partial shell  90  are combined to enclose the printed circuit board  70  and the connector  50  as shown by arrows A and B, the connector  50  is inserted into the connector cover  82  in such a way that the extension  56  rests on the base portion  84  of the connector cover  82 . When viewed from the front/network end (indicated by arrow C), the dimensions of the inner walls of the connector cover  82  look substantially similar to the dimensions of the inner walls of cavity  18  (see  FIG. 1 ).  
         [0028]      FIG. 6  depicts a module  94  that is assembled in accordance with the invention. Unlike the GBIC module  20 , which includes a conventional connector jack  10  to provide an interface and a separate shell to encapsulate or capture the connector jack  10 , both the functions of the connector jack  10  and the functions of the shell are served by the same mechanisms in the module  94 . Thus, the connector  50  and the connector cover  82  together form a dual-function network interface device. With mechanical components serving both functions, the dimensions of the module  94  at the network end can be made smaller than the dimensions of the GBIC module  20 . As a result, the module  94  can comply with the dimensional standards for a smaller (e.g., SFP) module. If the module  94  is made to comply with the SFP standards which require a smaller printed circuit board, some functionalities may need to be transferred from the printed circuit board in the GBIC module  20  into the connector  50  and the ribbon connector  62  in the module  94 . A person of ordinary skill in the art would know of various other measures that can be adopted to further reduce the overall dimensions of the module. These measures include inductive coupling of the cable side with the printed circuit board side of the connector  50 , impedance matching of resistors to prevent reflections, and connecting the ground on the cable side with the ground on the printed circuit board side via a high-voltage capacitor, wherein these features are included into the connector  50 .  
         [0029]     When combined with the connector  50 , the connector cover  82  form a cavity  53  with leads  52  positioned therein. The cavity  53 , which is similar to the cavity  18  except that it is made of an EMI-shielding material, serves to both hold a cable connector in place and to contain electromagnetic radiation. Protrusions  86  may be formed on one or more inner walls to customize the shape of the cavity  53  to fit the connection component. In the particular embodiment shown, the protrusions  86  are designed to fit along the sides of a “bump” on the standard RJ-45 cable connector (see  FIG. 1 ).  
         [0030]     The invention is not limited to the connector  50  or the module shell  80 ,  90  being made of specific materials. A person of ordinary skill in the art will appreciate that the partial shells  80  and  90  do not have to be made of metal if electromagnetic radiation shielding is not necessary. For example, if the electric components within the module do not generate much radiation, the partial shells  80  and  90  may be made of plastic without deviating from the spirit of the invention.  
         [0031]     Optionally, the module  94  may include a latching mechanism.  FIG. 7A  and  FIG. 7B  depict an embodiment of a pluggable module  94  having a latching mechanism that facilitates the unplugging of the module  94  from a host device (not shown). For clarity of illustration, only a part of the connector cover  82  is shown in  FIG. 7A  and  FIG. 7B . The latching mechanism includes a bail  102  that can be placed in different positions and attendant mechanisms for moving the bail  102  between the two positions. Further details about these mechanisms are provided in U.S. Pat. No. 6,439,918, which is incorporated herein. The bail  102  may be used either for securing the module  94  to the host device (see  FIG. 7A ) or for easy release (see  FIG. 7B ). The latching mechanism is implemented in such a way that it does not affect the overall dimensions of the module  94 . The bail  102  is preferably made of a rigid metal wire and is shaped so that it conforms substantially with the shape of the module  94  when placed in a “latched” position, as shown in  FIG. 7A . When the bail  102  is in a “release” position, as shown in  FIG. 7B , a portion of the bail  102  protrudes from the module  94  to form a clasp that can be pulled on with a finger to detach the module  94  from the host device. The bail  102  may be configured in any shape that is appropriate for the functions described herein.  
         [0032]     When the latching mechanism is included in the module  94 , the connector  50  is designed to accommodate the bail  102  in both the “latch” position and the “release” position, and to ensure a comfortable transition between the two positions.  FIG. 8  depicts a top view of the connector  50  clearly showing the waist  55  transitioning the outer surface  54   f  from a wider width D 1  to a narrower width D 2 . The portion of the connector  50  that are distanced apart by the wider width D 1  contacts the inner walls of the connector cover  82  when the module  94  is assembled. However, the portion of the outer surfaces  54   d  and  54   e  that are spaced apart by the narrower width D 2  do not touch the walls of the connector cover  82 , forming a gap  120  for bail clearance. This gap  120 , along with the cavity formed by the third outer surface  54   c  and the transitional section  60  (described above in reference to  FIG. 4 ), accommodates the bail  102 .  
         [0033]      FIG. 9  depicts a view of the assembled module  94  from the front/network end. As shown, parts of the bail  102  fit into the gap  120  between the connector  50  and the connector cover  82 . Since the cavity  53  is dimensioned to fit a particular cable connector, the bail  102  might interfere with the cable connector being securely and comfortably being inserted into the cavity  53 . Thus, the bail  102  is designed such that when it is in the operational “latched” position, it does not occupy parts of the cavity  53 , as shown in  FIG. 10 . On the other hand, it does not matter if the bail  102  occupies part of the cavity  53  when it is in the “release” position (see  FIG. 7B ) because it is unlikely that the module  94  will be unplugged or released from the host device while it is still communicating with the host device.  
         [0034]      FIG. 11  depicts a completely assembled module  130  including the connector  50  and the latching mechanism in accordance with the invention, wherein the bail  102  in its “latched” position.  
         [0035]     A person of ordinary skill in the art would understand that various modifications may be made to the module connector described herein without straying from the scope of the invention.