Abstract:
GBIC frames are mounted with respect to one or another or with respect to the printed circuit board so as to facilitate space sufficiency, e.g. of a front or other panel. In one aspect two GBIC frames are mounted in back-to-back fashion on opposite surfaces of a mounting plate of preferably minimal thickness. Plate cut-outs are positioned to accommodate frame feet or other mounting structures in a fashion off-set, on opposite faces, to avoid interference between frame legs. In one aspect, portions of GBICs and frames are received in cut-out or other edges of a PCB so that GBICs in frames straddle a major surface of a PCB to reduce height for accommodating 1RU or other form factors while increasing space efficiency.

Description:
Cross-reference is made to U.S. patent application Ser. No. 09/321,066, of MacKay, filed May 27, 1999 for “DISTRIBUTED NETWORK REPEATER SYSTEM”; U.S. patent application Ser. No. 09/330,478, of MacKay, Parameswaran, Twiss and Covaro for “CABLE DETECT AND EMI REDUCTION APPARATUS AND METHOD”, filed on even date herewith; U.S. patent application Ser. No. 09/330,733, of Dejager, Chen, Sinha, MacKay Parameswaran, and Twiss for “DISTRIBUTED NETWORK REPEATER MODULE AND METHOD”, filed on even date herewith; and U.S. patent application Ser. No. 20/106,266, for “REPEATER MODULE” of Steve Huang, Robert Gregory Twiss, Van Van Nguyen, and Ken Wood, filed on even date herewith, all incorporated herein by reference. 
    
    
     The present invention relates to a method and apparatus for providing two or more gigabit interface converter (GBIC) connectors which are relatively closely spaced and in particular to providing multiple GBIC connectors to achieve efficient use of a panel area or other region. 
     BACKGROUND INFORMATION 
     Numerous types of connectors for providing coupling to cables, fiber optic lines, or other communication media are used in various electronic devices including network devices such as network routers, switches, bridges, gateways and the like. As needs for communication links and/or connectors having various characteristics arise, different connector configurations give rise to standards defining the shape and size of the connectors or their components. One such type of connector is termed a gigabit interface converter (GBIC). In accordance with published or defacto standards, the GBIC includes a face region generally rectangular in shape, and having a size of approximately 1.2 inches by 0.3 inches (about 3 cm by 0.75 cm). This face region represents the region to which users typically will need or want to have access, such as for making connections. Accordingly, when a GBIC is to be part of an apparatus, such as a network router, the GBIC is positioned in the router such that the GBIC face region is accessible to the user. Typically this involves positioning in a portion of an accessible surface of the router cabinet such as preferably, the face plate of the router cabinet. 
     A number of published and/or de facto standards have emerged to define preferred shapes and sizes for many electronic components such as network routers. For example, particularly when a router is to be compatible with rack-mounting, it is desirable to provide the router cabinet with a face plate having a size of about 1¾ inches by about 17½ inches (about 4.5 cm by about 45 cm). Such a size is compatible with the so-called 1RU form factor. When the face panel (or other surface) of an electronic device, such as a router, needs to have numerous components, such as numerous connectors, signal lights or other displays, switches and the like, it becomes important to make efficient use of the available surface area of the front panel (or other surface), particularly when it is desired for the front panel to be sized and shaped in accordance with the RU form factor or other published or de facto standard (which limits the surface area available for such components). Accordingly, when a network router or other electronic component is to be provided with two or more GBICs, it would be useful to provide for mounting of the GBICs in a fashion which is achieves space efficiency of the face plates with respect to the two or more GBIC connectors. 
     When GBICs are mounted using GBIC frames for holding the GBICs, there are numerous costs and other advantages to employing GBIC frames which correspond to published or de facto GBIC frame standards. Accordingly, it would be useful to provide for mounting of two or more GBIC frames in a space-efficient manner substantially without requiring modification of a standard GBIC frame configuration. 
     As GBIC designs have emerged, GBIC frames typically, are configured to accommodate a single GBIC and to accommodate mounting on or with respect to a circuitry component which is a printed circuit board (PCB), with a separate mounting device provided for each GBIC. It is believed that, in general, standard GBIC frame designs were developed at time periods when a single GBIC per router was considered adequate. Current systems, however, make it increasingly useful to provide two or more GBICs in a router. Accordingly, it would be useful to provide a method and apparatus for mounting multiple GBICs preferably using substantially standard GBIC frames, in a manner which is space-efficient. 
     Achieving closely-spaced mounting of two or more GBICs places constraints on the amount of volume defined between the GBICs (or otherwise in the vicinity of the GBICs). However, in a typical application, certain electronic components such as serializer-deserializer (“SerDes”) chips, should preferably be positioned relatively close to the GBICs such as within about 2 inches (5 cm), more preferably, about 1 inch (about 2.5 cm) or less. 
     In some designs, short signal paths can be difficult to implement. For example, relatively long signal paths may be necessary when such components are positioned on a PCB which is separate from the PCB to which the GBIC is mounted or otherwise directly coupled. Accordingly, it would be useful to provide a method and apparatus for mounting two or more GBICs in a space-efficient fashion while permitting the coupling of SerDes chips, or other electronic components to the GBICs with signal paths less than about 2 inches (about 5 cm). 
     In addition to the electrical connection between the GBIC and one or more PCBs or other circuit components, the integrity of the mechanical coupling between the GBIC and associated PCBs can be of importance in maintaining the desired electrical connections, especially in the face of jostling or movement that can result as cables, fiber optics and the like are engaged or disengaged with the device. Accordingly, it would be useful to provide a method and apparatus for mounting two or more GBICs which achieves or enhances the mechanical support of the GBIC e.g. with respect to a PCB or other component. 
     In a typical configuration, a GBIC connector is mounted substantially directly on one or another surface of a PCB board (such as a “motherboard”). Typically, the motherboard will be positioned along the long axis of the chassis and with the plane of the motherboard perpendicular to the plane of the faceplate. In some configurations, a GBIC is mounted with the long axis of its face parallel to the plane of the motherboard (i.e. with the long axis of the GBIC face parallel to the long axis of the chassis faceplate). This provides a relatively favorable height requirement in the sense that such a configuration can readily be contained within the 1.75 inch (about 44.5 mm), maximum height of an RU form factor faceplate. however, this means each GBIC will occupy at least about 1.44 inches (about 3.5 cm) out of the maximum 17.5 inch (about 44.5 cm) lateral space available for the RU form factor, thus limiting the number of GBICs that can be mounted with respect to an RU face plate. Of course, the amount of lateral dimension occupied by GBIC connectors can be reduced by mounting the GBICs with the long axis of the GBIC face perpendicular to the long axis of the faceplate (and thus, typically perpendicular to the motherboard). Unfortunately, it proves infeasible to accommodate the full height of a GBIC connector plus the thickness of the motherboard plus an allowance for airspace, cabinet wall thickness and like, within an RU height form factor (i.e. 1.75 inches or about 44.5 cm). Accordingly, it would be useful to provide a configuration for mounting a GBIC connector with respect to a circuit board which permits the GBIC to have the long axis of the GBIC face perpendicular to the long axis of the RU face plate, yet still configure the router or other device within an RU height form factor of about 1.75 inches (about 44.5 mm). 
     SUMMARY OF THE INVENTION 
     The present invention includes the recognition of problems that arise in going from an apparatus or system having a single GBIC connector to one which has two or more GBIC connectors. In one aspect, the present invention includes providing an attachment plate configured to receive and/or accommodate two GBIC frames which are positioned in back-to-back fashion (i.e. with corresponding surfaces facing each other). This results in a configuration in which the frames are in a mirror-image (“back-to-back”) configuration with respect to one another about a plane passing tlirough the attachment plate. Preferably the attachment plate itself is also mirror-symmetric about a plane passing through its midline. In one embodiment the attachment plate is electrically and/or mechanically (preferably both) coupled to a PCB. By coupling an edge of the attachment plate to the PCB, preferably with the symmetry plane substantially perpendicular to the PCB, the proximity of the frames to the PCB is sufficient that SerDes device, or similar electronic component mounted on the PCB can define a signal path less than about 2 inches (about 5 cm). In one embodiment, in addition to mechanical mounting or coupling of the attachment plate to the PCB, one or more of the GBIC frames are also directly mechanically linked to the PCB to provide enhanced structural integrity. 
     In one aspect, the present invention includes positioning a GBIC with respect to a PCB such that the GBIC is not located entirely on one side of a major surface of the PCB. In one embodiment, the PCB includes a slot or edge for receiving or coupling to one or preferably two or more GBICs so that one portion of the GBICs are positioned one side of a major surface of the PCB and another portion are positioned on the opposite side of the major surface of the PCB. Preferably the GBIC is mounted such that one portion extends upwardly above an upper surface of the PCB and another portion extends downwardly below the lower surface of the PCB. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a GBIC frame; 
     FIG. 2 is a perspective view of a frame attachment plate according to an embodiment of the present invention; 
     FIG. 3 is a perspective view of two coupled GBIC frames adjacent a PCB according to an embodiment of the present invention; 
     FIG. 4 is a schematic front elevational view, partially broken away, illustrating certain height relationships of a GBIC, PCB and chassis; 
     FIG. 5 is a front elevational view, partially broken away, of a chassis having a PCB and a GBIC showing certain height relationships, according to one embodiment of the present invention; 
     FIG. 6 is a perspective view of an RU form factor device with GBICs mounted according to an embodiment of the present invention; 
     FIG. 7 is a side view of a GBIC and PCB according to an embodiment of the present invention; 
     FIG. 8 is a perspective view of the device of FIG. 7; and 
     FIG. 9 is a perspective view of a tapered GBIC pair according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     As shown in FIG. 1, a GBIC frame  112  is configured to receive a GBIC  114  by insertion  116  through a substantially rectangular front opening or face  118  of the frame. Each of the GBIC frames  112  can be formed of a number of materials such as resins, plastics, fiber reinforced materials. and the like. The bottom surface of the front opening  118  defines a first plane  122  of the frame having a mid-line  123 . The frame  112 , in the depicted configuration, includes first and second sidewalls  124 ,  126  extending between the front opening  118  and a rear opening  128 . The GBIC frame  112 , with the exception of the downwardly extending portions of frame feet, described below, generally fits within a rectangular parallelepiped volume (of which one surface is the plane  122 ). The frame  112  in the configuration depicted in FIG. 1, includes six foot structures  132   a,b,c,d,e,f  extending downward distances  134   a,b,c,d,e,f  from the plane  122 . In some previous approaches, the GBIC frame  112  is positioned on a PCB with the plane  122  co-planar with a major surface of the PCB and the feet  132   a-f  extending thiough recesses or holes formed in the PCB. Such a configuration means that the major axis  138  of the opening  118  is parallel to the plane  122  of the PCB. If, as would be commonly the case in such configuration, the PCB is positioned parallel to the long axis of the front cover of the router or other device, only a relatively few GBICs can be positioned on the front plate, i.e. the GBIC opening occupies a relatively wide longitudinal extend  138  of the front panel. 
     In the depicted configuration, the feet extending from opposite sidewalls are longitudinally off-set from one another. For example, foot  132   a  extends forward  142   a  of a lateral line  144  (which is perpendicular to the mid-line  123 ) while a corresponding foot  132   b  extending from the opposite sidewall  126  extends rearward  142   b  from the lateral line  144 . Similarly, foot  132   c  extends forward  142   c  of lateral line  146  while foot  132   d  extends rearward  142   d  of foot  132   d . Foot  132   e  extends forward  142   e  of lateral line  148  while foot  132   f  extends rearward of line  148 . 
     According to one embodiment of the invention, GBIC frames are coupled to opposite sides of a connector plate  212  (FIG. 2) so that two GBICs can be positioned in a relatively close proximity to one another, in back-to-back fashion. The plate  212  can be formed of a number of materials, including fiberglass materials, resin materials such as fiber reinforced resins, plastics, ceramics and the like. In one embodiment, plate  212  has a thickness  214  of about 0.150 inches (about 3.8 mm) which is substantially thicker than a typical PCB (which typically have a thickness of approximately 0.06 inches or about 1.5 mm). Although it would be possible to provide plates  212  having relatively greater thicknesses, it is preferred to use a plate  212  which is substantially as thin as feasible (while providing desired rigidity and accommodation for GBIC feet or other mounting structures). In this regard, it is useful to provide for frame feet which are off-set from one another, e.g. in longitudinal directions (such as with respect to lateral lines  144 ,  146 ,  148  as described) since this permits use of more than half the thickness  214 , of the plate  212  for accommodating the feet of a GBIC frame coupled to one surface  216  without creating interference with respect to the feet from a GBIC frame coupled to opposite surface  218 . For example, if the frame  112  of FIG. 1 is coupled to the upper surface  216  of the plate  212  of FIG. 2, foot  132   c  can protrude a distance  134   c  which may exceed one-half the plate thickness  214 , though an opening  222 , preferably with an aligned cut-out  224  to accommodate an outwardly projecting tooth  152  of foot  132   c  (FIG.  3 ). This attachment does not, however, create interference with respect to a GBIC frame attached to the lower surface  218  since the closest foot, to opening  222  for such a second frame would be foot  132   d  which, as described above, is off-set in a rearward direction  142   d  with respect to the position of foot  132   c  and accordingly can be accommodated in the rearwardly positioned opening  226  of the plate  212  (continuous with opening  222  in the depicted embodiment) and the tooth  154  of foot  132   d ′ of the second GBIC  112 ′ (FIG. 3) can be accommodated in a second cut-out  228 . Similar off-set configurations with respect to holes  232   a ,  232   b ,  232   c ,  232   f  accommodate, in a non-interfering manner, remaining feet of both a first GBIC frame  112  and a second GBIC frame  112 ′, as shown generally in FIG.  3 . In this fashion, longitudinally off-set openings as depicted in FIG. 2 provide for back-to-back coupling of two GBIC frames to a relatively thin plate such as, e.g., a plate having a thickness  214  of about 0.15 inches (about 4 mm) and transverse (i.e. perpendicular to plane  122 ) length  312  of about 0.75 inches (about 2 cm). 
     One feature of the configuration of the plate of FIG. 2 is that the plate is preferably symmetric about its mid-plane  234  in the sense that, when assembling a particular frame  112  to the plate  212 , it does not matter which surface  216  or  218  is uppermost, since the openings  222 ,  226 ,  232   a,b,e,f  will appear identical when either side is uppermost. This simplifies manufacture since during assembly it is not necessary to couple a particular frame configuration to a particular side. Similarly this means that the frames  112 ,  112 ′ coupled to opposite sides of the plate  212  can be have identical configurations, i.e. it is not necessary, during assembly, to select between frame configurations, with one frame configuration to be coupled to one side of the plate and the other plane configuration be coupled to the other side of the plate. 
     In the embodiment of FIG. 3, the back-to-back coupled GBIC frames, can be coupled to a PCB  314 , e.g. by mounting the plate  212  with respect to the board  314 . Preferably, edges of the GBIC frames are also mounted to the PCB  314  e.g. using mounting tabs  315  to provide additional stability and reduce relative motion. In addition to, or in place of, tabs  315 , mounting or coupling can be achieved or enhanced by any conventional means, including by adhesive, soldering or welding, using brackets, tracks, or other mounting components and the like. 
     In the configuration of FIG. 3, the longitudinal axis  123  of the GBICs are substantially perpendicular to the PCB  314 . In other configurations, it is preferred to mount GBICs with respect to a PCB such that the longitudinal axis  123  is parallel to the PCB. One possible approach is depicted in FIG. 4 in which a motherboard or other PCB  412  extends along the long axis of a chassis  414 , e.g. of a network router or similar device. In the embodiment of FIG. 4, a GBIC and frame  416  is mounted with a sidewall flush on the upper major surface  418  of the PCB  412 . (GBICs and frames in FIGS. 4,  5 , and  8  are depicted as parallelepipeds, for simplicity.) In the configuration of FIG. 4, the entire vertical extent of the device  422  must take into account a number of items. In the embodiment of FIG. 4, the lower wall or plate of the chassis occupies a certain thickness  424  such as, for example, 0.4 inches (about 10 mm) (not to scale in FIG.  4 ). A certain clearance  413  is provided between the bottom plate  423  and the PCB  412 , such as about 0.25 inches (about 6 mm), to provide an accumulated distance  426  of 0.29 inches (about 7 mm). The thickness of the PCB  412  adds a further amount such as about 0.06 inches (about 1.5 mm) to bring the accumulated thickness  428  to 0.35 inches (about 9 mm). The GBIC  416  (including an allowance for the thickness of the GBIC frame) adds an additional height  417  of about 1.24 inches (about 36 mm) to bring the accumulated height  432  to about 1.69 inches (about 43 mm). Finally, a clearance or airspace between the GBIC  416  and the upper wall or plate  434  in the amount  431  of about ⅛ inch (about 3 mm) brings the total height of the device  422  to 1.815 inches (about 46 mm). As noted above, the 1RU standard height is 1.75 inches (about 44.5 mm) and thus the configuration of FIG. 4, if the clearances depicted are observed, cannot be accommodated in a 1RU form factor device. 
     FIG. 5 depicts an embodiment which provides for mounting one or more GBICs in an upright configuration, with the long axis of the opening  138  perpendicular to the plane of the board  412 . (The embodiment of FIG. 5 provides for relatively small lateral extent  514  of the GBICs  516   a ,  516   b  while still accommodating the device in an 1RU form factor having a height  522  of about 1.75 inches (about 44.5 cm), preferably while still providing clearance between the lower plate  523  and the bottom of the GBICs  516   a,b  and between the upper plate  530  and the upper surface of the GBICs  516   a,b  of at least ⅛th inch (about  3  mm). In one embodiment, as depicted in FIG. 8, the PCB  512  is provided with a cut-out  812  sufficient to accommodate one or more GBICs, preferably sufficient to accommodate first and second GBICs  516   a ,  516   b  and frames mounted back-to-back on a plate  212  as well as to accommodate portions of first and second rails  814   a,b  which are mounted on the GBIC frames  516   a ,  516   b . As depicted in FIG. 5, using this construction, a certain portion  552  of the GBICs  516   a ,  516   b  (and frames) extend below the upper surface  518  of the PCB  512  with the remaining portion  554  extending above the upper surface  518  of the PCB  512 . In this way, it is not necessary for the chassis to have a height  522  sufficient to accommodate the accumulated height of the GBIC plus the thickness of the PCB  412  (and other items). Instead, the height  522  need only accommodate the height of the GBICs (and frames)  516   a ,  516   b  plus clearances above and below the GBIC (and chassis walls). It may be possible to provide relatively little clearance  536  between the GBICs  516   a, b  and the chassis bottom  525 , such as less than about ⅛ inch (about 3 mm). Further, in one embodiment, the region of the chassis bottom  523  adjacent the GBIC frames is “scooped out” to provide a thinned chassis wall and achieve desired clearance. 
     FIG. 6 is a perspective view of a network router showing the front plate thereof. The depicted device complies with RU form factors by having a height  612  of 1.75 inches (about 44.5 mm) and a width  614  of 17.5 inches (about 450 mm). By using a configuration similar to that depicted in FIG. 5, GBIC front faces can be accommodated in the front plate  616  of the device in a space-efficient manner by positioning with the long axis of the GBIC faces in the direction of the 1.75 inch (about 44.5 mm). height of the device, thus occupying relatively little width such as providing for two back-to-back mounted GBICs occupying a width  618  of about 1⅜ inch (about 35 mm). 
     As depicted in FIG. 7, in one configuration, a GBIC  516   b  communicates with components (such as a SerDes chip) on the PCB  512  via a connector  712  which includes a wire, cable or flexible link path. By positioning the back end  816  of the GBIC  516   b  near the SerDes, (as can be done when the GBIC  516   b  is coupled, e.g. by rail  814   b  to an edge or recess of the PCB  512 ), the length  714  of the signal path (which is typically a high frequency serial signal, e.g. of, e.g. 1.25 Ghz) can be relatively short such as less than about two inches (about 50 mm), preferably less than about 1 inch (about 25 mm). The (typically parallel) signals output by the SerDes chip are lower frequency signals e.g. 10-bit, 125 MHZ signals, where the length of the signal path is of less concern. 
     In the configuration of FIG. 8, the surface area of the PCB which must be cut-out (and is thus unavailable for positioning circuitry), has a width  819  at least equal to the transverse dimension  312  of two stacked GBICs (and frames) plus an allowance for the rails  814   a,b . In the configuration of FIG. 9, the GBICs, while having the standard GBIC frame (double) height  514  and width  417  , provides for more forward portions of the GBICs (and frame) in a flared configuration  942 , so that the configuration of FIG. 9 can be accommodated by a PCB slot which, at least in the rearmost portion of the PCB slot, can have a width commensurate with the above-described stacked-GBIC width  514  while the openings of the GBICs can have heights  939  larger than those in the embodiment of FIG.  3 . The configuration of FIG. 9 will receive first and second differently shaped (mirror image) GBICs. 
     In light of the above description, a number of advantages of the present invention can be seen. The present invention permits two or more GBICs, and GBIC frames, to be mounted in relatively close proximity in substantially parallel fashion, preferably in substantially back-to-back configuration. The present invention facilitates mounting of GBICs in a fashion to promote space efficiency, c.g. by reducing the lateral and/or vertical extent required for a given number of GBICs, e.g. GBIC faces accessible on a face panel. The present invention facilitates providing a relatively large, preferably maximal, number of GBICs within a 1RU form factor. The present invention provides for mounting of GBICs and GBIC frames with respect to a PCB in a secure and stable manner. The present invention facilitates mounting GBICs in close proximity to components such as a serializer/deserializer, e.g. to provide for relatively short high-frequency signal paths. 
     A number of variations and modifications of the invention can be used. It is possible to use some aspects of the invention without using others. For example, it is possible to provide a plate for back-to-back mounting of two GBIC frames without mounting frames to extend on opposite sides of (or straddle) a PCB (and vice versa). Although embodiments of the present invention have been described in coiLmection with accommodating a 1RU form factor, the present invention can also be used to accommodate other form factors. Although the present invention has been described in connection with GBIC connectors used for routers, the present invention can also be used for devises where GBIC connectors are used for other purposes such as network switches, bridges and the like. The present invention can be used for accomodating devices other than GBIC connectors, such as components of a repeater or similar system, and/or non-GBIC connectors. Although an embodiment has been described in which a separate plate  212  is provided, to which two GBIC frames are mounted in back-to-back fashion, it is also possible to provide a single GBIC frame which can accommodate two GBICs in back-to-back fashion, as a unitary piece, or to provide one or both of the GBIC frames formed integrally (as a single piece) with a plate. 
     The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g. for improving performance, achieving ease and\or reducing cost of implementation. 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. Although the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g. as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures , functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.