Abstract:
A latch mechanism for use with an electronic module, such as an opto-electronic transceiver module. The latch mechanism allows the user to selectively extract the transceiver module from the port by moving an attached bail between a first and second position. Specifically, the bail is connected to, and configured to translate, a pair of sliders that are configured and arranged to engage, and disengage from, corresponding structure of the port. When the bail is in the first position, the sliders releasably engage corresponding structure of the port. When the bail is moved from the first position to a second position, the sliders disengage from the corresponding structure of the port, thereby enabling unhindered extraction of the module from the port.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation, and claims the benefit, of U.S. patent application Ser. No. 10/685,913, entitled TRANSCEIVER LATCH MECHANISM, filed Oct. 15, 2003, which in turn claims the benefit of U.S. Provisional Patent Application Ser. No. 60/419,156, entitled XFP TRANSCEIVER BAIL, filed on Oct. 16, 2002. Both of the aforementioned applications are incorporated herein in their respective entireties by this reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to the field of connector systems for optical and electrical components. In particular, embodiments of the present invention relate to a latching system that is useful in connection with small form factor, user-removable, electronic modules that interface with a port of a host device. 
   2. Related Technology 
   Fiber optic transmission media are increasingly used for transmitting optical, voice, and data signals. As a transmission vehicle, light provides a number of advantages over traditional electrical communication techniques. For example, optical signals enable extremely high transmission rates and very high bandwidth capabilities. Also, optical signals are unaffected by electromagnetic radiation that causes electromagnetic interference (“EMI”) in electrical signals. Optical signals also provide a more secure signal because the optical transmission medium, such as an optical fiber, does not allow portions of the signal to escape, or be tapped, from the optical fiber, as can occur with electrical signals in wire-based transmission systems. Optical signals can also be transmitted over relatively greater distances without experiencing the signal loss typically associated with transmission of electrical signals over such distances. 
   While optical communications provide a number of advantages, the use of light as a data transmission vehicle presents a number of implementation challenges. For example, prior to being received and/or processed, the data represented by the optical signal must be converted to an electrical form. Similarly, the data signal must be converted from an electronic form to an optical form prior to transmission onto the optical network. 
   Typically, these conversion processes are implemented by way of optical transceiver modules located at either end of an optical fiber. Each optical transceiver module typically contains a laser transmitter circuit capable of converting electrical signals to optical signals, and an optical receiver capable of converting received optical signals into electrical signals. 
   Typically, an optical transceiver module is electrically interfaced with a host device, such as a host computer, switching hub, network router, switch box, or computer I/O, via a compatible connection port. In some applications, it is desirable to miniaturize the optical transceiver module as much as possible to increase the port density. Generally, port density refers to the number of network connections within a given physical space, so that a relative increase in the number of such network connections within the defined physical space corresponds to a relative increase in port density. 
   Because the optical transceiver modules occupy a significant amount of space on the host device, reducing the physical space needed for each optical transceiver module allows for a relatively higher port density. In addition, it is desirable in many applications for the module to be “hot-pluggable,” which means that the optical transceiver module may be inserted and removed from the host system without securing the electrical power to the module or host. In an attempt to accomplish many of these objectives, international and industry standards have been adopted that control the physical size and shape of optical transceiver modules. Among other things, such standards help to insure compatibility between systems and components produced by different manufacturers. 
   One example of such an optical transceiver module is the z-axis hot pluggable module of the 10-Gigabit Small Form-factor Pluggable (XFP) Module Group, a module Multi Source Agreement (XFP-MSA) association. The XFP-MSA is an association of companies that has developed a specification for a 10 gigabit per second (“Gbps”) transceiver module having compatible mechanical and electrical features. The aforementioned type of optical transceiver module is sometimes referred to as an “XFP transceiver module” or simply an “XFP” module. 
   The XFP optical transceiver module is designed to slide into a port of a host device. On one end of the port is a so-called “right angle” surface-mount connector that fits through a bottom rear end opening of the port. The surface-mount connector is also connected to the host board. The rear end of the transceiver module includes a printed circuit board having a card-edge connector. This card edge connector mechanically and electrically interfaces with the host signal interface, which includes the aforementioned surface mount connector as well as associated high-speed interconnects. 
   A pluggable optical transceiver module, such as an XFP module, must be capable of being latched and unlatched to the port of the host device. If the optical transceiver module is not securely and reliably latched to the port, the card-edge connector of the optical transceiver module may disengage and disrupt transmission or reception of the data signal. The optical transceiver module should also be capable of being unlatched and removed in the event that the module requires, repair, testing or replacement. 
   The latch mechanism must also permit removal of the module while fitting within the dimensions defined by the MSA specifications. At least some transceiver standards specify a latching pin disposed on the transceiver module that serves to latch the module in the port. The latching pin is movably coupled to a bail such that the latching pin can be extended into a hole in the port to latch the module into place. However, such conventional latch mechanisms are not compatible with the XFP MSA specifications. 
   Therefore, there is a need for a module, such as an optical transceiver module, having a latch mechanism that locks the module to the XFP port and complies with MSA specifications. An exemplary latch mechanism should provide secure and reliable latch and unlatch functionality, provide a handle for extraction of the module from the host port, and be consistent with MSA or other applicable specifications. 
   BRIEF SUMMARY OF AN EXEMPLARY EMBODIMENT OF THE INVENTION 
   The foregoing, and other, problems in the prior art are addressed by embodiments of the present invention, which generally relate to a latch mechanism suitable for use in connection with an electronic, pluggable module. In one exemplary embodiment, the module is an opto-electronic transceiver module, typically used to interface an optical transmission cable to a host device, such as a network switch, hub, router, computer or the like. However, embodiments of the invention may be usefully employed in other environments as well. 
   In one exemplary embodiment, the module, wherein the latch mechanism is employed, comprises an XFP transceiver module in conformance with industry standards. The module is capable of being operatively received within a compatible port of a host device. 
   In this exemplary embodiment, the module includes a housing, which is divided into an upper housing and bottom cover. The housing supports a printed circuit board (“PCB”) upon which are disposed the electronics needed to implement the functionality of the module. The PCB has an edge connector formed at one end that is capable of electrically interfacing with the port of the host device when the module is operatively received within the device port. Also disposed on one end of the base portion of the module is at least one receptacle capable of physically receiving and interfacing with a corresponding optical fiber connector, which in turn is connected to a fiber optic cable. In this embodiment, the housing encloses at least a portion of the base and protects the electronic and optical components from dust and the like. Moreover, the housing defines an outer periphery that conforms in size and shape to a corresponding MSA standard host port. 
   Generally, the latch mechanism of the module enables the releasable securement of the transceiver module within the host port. Exemplarily, the latch mechanism is implemented within a transceiver module that conforms to the MSA standards for an XFP transceiver module and comprises a pair of sliders disposed within recesses defined by sidewalls of the module. The sliders are arranged for simultaneous linear motion by virtue of attachment to a bail of the latch mechanism. The bail is configured and arranged for rotational motion. The sliders cooperate with the module sidewalls to define opposing recesses configured to removably receive corresponding structure of the port wherein the module is to be inserted. 
   In operation, the module interacts with the port of the host when the module is operably received in the port. Specifically, the module is locked into the port when the module engages corresponding structure of the port. Release of the module from the port is effected by way of a moveable bail coupled to a slider through a cam. The bail is moveable between two positions that correspond, respectively, to positions where the module is latched to the port and where the module is unlatched from the port. That is, motion of the bail from the first position to the second position translates the slider between a first position where the slider enables the module to releasably engage the port (the latched position), and a second position where the slider causes the module to be disengaged from the port (the unlatched position). 
   As noted above, the module releasably engages corresponding structure of the port, such as a resilient tab that is biased into an engaging position. In this exemplary implementation, a recess cooperatively defined by the slider and module sidewall releasably receives the biased resilient tab of the port, thereby securing the module to the port. The module is released by moving the bail to a second position, which translates the slider so that as the slider moves, a ramp on the foot of the slider engages the resilient tab, flexing the resilient tab out of the recess defined by the slider and module sidewall and thus enabling retraction of the module from the port. 
   Among other things then, the latch mechanism permits easy insertion and extraction of the module by a user. In addition, extraction of the module can be accomplished without the use of a specialized extraction tool, and without disturbing adjacent modules and/or cables. 
   These and other aspects of embodiments of the invention will become more fully apparent from the following description and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the manner in which the above-recited and other aspects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
       FIG. 1  is an exploded perspective view of an exemplary implementation of a module and associated latch mechanism as employed in an exemplary operating environment; 
       FIG. 2A  is a perspective view illustrating an exemplary module that is unlatched from the port of an exemplary host device; 
       FIG. 2B  is a section view taken from FIG.  2 A and illustrating further details of the arrangement of the module with respect to the port when the module is unlatched from the port of a host device; 
       FIG. 2C  is perspective view illustrating aspects of the arrangement of a module with respect to a port of a host device when the module is fully received within the port of a host device; 
       FIG. 2D  is a section view taken from FIG.  2 C and illustrating further details of an exemplary arrangement of a module and associated latch mechanism with respect to the port when the module is latched to the port of the host device; 
       FIG. 3A  is a perspective view illustrating aspects of an exemplary slider such as may be employed in connection with the latch mechanism of  FIG. 2A ; 
       FIG. 3B  is a perspective view illustrating further aspects of an exemplary slider such as may be employed in connection with the latch mechanism of  FIG. 2A ; 
       FIG. 4A  is a front view of an implementation of a bail of the latch mechanism; 
       FIG. 4B  is a perspective view of the bail depicted in  FIG. 4A ; 
       FIG. 5  is a perspective view of the bottom of the module of  FIG. 2A , with certain parts of the module removed for clarity, indicating aspects of the structure of the module that pertain to the latch mechanism; 
       FIG. 6  is a side view illustrating aspects of an exemplary module and associated latch mechanism; 
       FIG. 6A  is a cross-section taken from FIG.  6  and illustrates aspects of the arrangement of the bail with respect to the slider; 
       FIG. 6B  is a cross-section taken from FIG.  6  and illustrates aspects of the arrangement of the sliders with respect to recesses defined in the sidewalls of the module; 
       FIG. 6C  is a cross-section taken from FIG.  6  and illustrates aspects of the arrangement of guide portions of the sliders with respect to guide slots defined in the sidewalls of the module; 
       FIG. 7A  is a bottom view of an exemplary module with the bottom cover removed and illustrates aspects of the arrangement and effect of resilient elements employed as part of an exemplary latch mechanism; 
       FIG. 7B  is a bottom view of an exemplary module with the bottom cover removed and illustrates aspects of the arrangement and effect of resilient elements employed as part of an exemplary latch mechanism; 
       FIG. 8A  is a perspective view of an exemplary module where the bail of the latch mechanism is in an upright position that corresponds to an arrangement where the module is latched to the port; 
       FIG. 8B  is a perspective view of an exemplary module where the bail of the latch mechanism is in an intermediate position that corresponds to a partial unlatching of the module from the port; 
       FIG. 8C  is a perspective view of an exemplary module where the bail of the latch mechanism is in a substantially horizontal position that corresponds to an arrangement where the module is unlatched from the port and the bail is positioned for use as a handle for extracting the module from the port; and 
       FIG. 8D  is a perspective view of an exemplary module where the bail of the latch mechanism is in a resting position that corresponds to an arrangement where the module is unlatched from the port. 
   

   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   In general, exemplary embodiments of the present invention relate to a latch mechanism suitable for use in an electronic module, such as an opto-electronic transceiver for example, to releasably secure the electronic module within a host slot or port assembly. Moreover, the latch mechanism can be implemented within transceiver modules that conform to industry standards. The latch mechanism permits easy extraction and insertion of the module by a user, even when the module is used in a host system having a higher-density port configuration than permitted by the MSA, such as when the modules are disposed in ports immediately nearly adjacent to one another in one or both lateral dimensions. 
   Thus, while exemplary embodiments of the invention are implemented in an MSA-compliant form, such embodiments may nonetheless be readily employed in connection with non-MSA compliant systems and devices, examples of which include those systems and devices that include, or require, non-MSA compliant high-density port configurations. Another aspect of exemplary embodiments of the invention is that extraction of the module can be accomplished without the use of a specialized extraction tool, and can be performed without disturbing adjacent modules and cables. 
   While embodiments of the present invention are described in the context of optical transceiver modules used in the field of optical networking, it will be appreciated that embodiments of the invention may be employed in other operating environments where the functionality disclosed herein may be useful. Accordingly, the scope of the invention should not be construed to be limited to the exemplary implementations and operating environments disclosed herein. 
   I. Exemplary Structural Aspects of an Implementation of the Invention 
   Reference is first made to  FIG. 1 , which illustrates a partially exploded view of a host device  100  that includes a printed circuit board  102 , a host interface  104 , and a heat sink  106 . The host device  100  is configured to receive, and operably interact with, a module  200 , such as an optical transceiver module for example, by way of a port  300  disposed on the printed circuit board  102 . The heat sink  106  is positioned over the port  300  so as to dissipate heat generated by operation of the module  200 . 
   When embodied as an optical transceiver, the module  200  generally operates to transmit and receive optical signals over transmission media such as fiber optic cables. To that end, some exemplary implementations of module  200 , aspects of which are indicated in  FIG. 5  discussed below, include, in addition to a module housing  202  having module sidewalls  202 A, bottom cover  202 B, and edge connector  204 , various components configured and arranged to transmit and receive optical signals, including a receive optical subassembly (“ROSA”)  206 , and a transmit optical subassembly (“TOSA”)  208 . The various internal components are housed with the module housing  202 . 
   Generally, the edge connector  204  serves to enable communication between the module  200  and the host device  100  by electrically interfacing with port  300 . More particularly, the module  200  receives, from port  300 , the electrical data signal that is to be transmitted as an optical signal. Likewise, the module  200  sends data to the host device  100 , by way of port  300 , that the module  200  has received in optical form and converted to electrical form. In addition to the aforementioned components, exemplary implementations of module  200  typically include a pair of optical cable ports  210  ( FIG. 5 ) where a pair of fiber optic cables can be optically coupled. 
   It should be understood that while many of the figures herein illustrate only one side, or a portion of, components such as the module  200 , the configuration of the module is generally symmetric so that the configuration and arrangement of the module and latch mechanism on one side of the module substantially mirrors the configuration and arrangement of the module and latch mechanism on the other side of the module. Thus, while reference may be made herein to one side of the module and/or latch mechanism, such discussion is equally germane to the other, non-illustrated, side of the module and latch mechanism. 
   Directing attention now to  FIGS. 2A and 2B , further details are provided concerning the arrangement of the module  200 , with respect to the port  300  of the host device  100 , when the module  200  is partially received in the port  300 . Exemplarily, the port  300  includes two resilient tabs  304  that are biased inward from the sidewalls  302  of port  300 . As indicated in the Figures, the module  200  includes a bail  212 , as well as a pair of sliders  214  that are disposed on opposite sides of the module  200  and each of which includes a respective ramp  216  configured and arranged to interact with a corresponding resilient tab  304  of the port  300 . 
   As suggested in the Figures, the position of the bail  212  generally corresponds to a particular disposition of the sliders  214  and corresponding ramps  216 . More particularly, the exemplary illustrated embodiment of the module  200  is configured such that a substantially horizontal bail  212  position corresponds to an unlatched arrangement of the module  200  relative to the port  300 . In general, motion of the bail  212  causes operative motion of the sliders  214 , so as to effect removal and insertion of the module  200  with respect to the port  300 , as discussed in further detail below. 
   Details concerning the situation where the module  200  is removably latched to the port  300  are provided in  FIGS. 2C and 2D . As indicated in the Figures, each slider  214  of the module  200  generally cooperates with a corresponding sidewall  202 A of the module housing  202  to define a recess  218  configured and arranged to enable latching of the module  200  to the port  300  by removably receiving the resilient tab  304  of the port  300 , as best illustrated in FIG.  2 D. More particularly, the latched arrangement indicated in  FIGS. 2C and 2D  is achieved when the resilient tab  304 , biased inward toward the module  200 , is removably received within the recess  218 . The end wall  242  of the recess  218  is substantially perpendicular to the resilient tab  303  creating a barrier that prevents the module from being withdrawn from the port  300 . 
   Any other structural arrangement that is effective in providing functionality comparable to that implemented by the recess  218  and resilient tab  304  may alternatively be employed. Accordingly, the scope of the invention should not be construed to be limited to the disclosed exemplary implementations. 
   With attention now to  FIGS. 3A and 3B , further details are provided concerning an exemplary implementation of the slider  214  in connection with which the module  200  is latched to, and unlatched from, the port  300 . As generally indicated in  FIGS. 3A and 3B , the illustrated exemplary embodiment of the slider  214  is symmetrical about a longitudinal axis. As a result of this configuration, the same slider  214  design can be used to manufacture sliders for both sides of the module  200 , thereby reducing manufacturing cost. The slider  214 , as well as the bail  212 , may be constructed of any suitable material(s) or combinations thereof including, but not limited to, plastic and metal. 
   With particular reference first to  FIG. 3A , a perspective view of a first side of the slider  214 , arranged to face outward from the module  200  toward the sidewall  302  of the port  300 , is indicated. The slider  214  includes upper and lower guide portions  220  configured and arranged to cooperate with corresponding structure of the module sidewall  202 A, discussed below, to define a range of sliding linear motion for the slider  214 . In addition, the slider  214  includes an incline portion  222  that terminates in the ramp  216 . 
   As indicated in  FIG. 3B , the opposing side of the slider  214  includes structure arranged to interact with corresponding structure in the module housing  202 , so as to collectively define a recess for housing a resilient element  248  (see, e.g., FIGS.  7 A and  7 B). Specifically, a step  224  is defined in the opposing side of the slider  214  that cooperates with a corresponding element in the module housing  202  to create a pair of parallel surfaces to which the resilient element  248  applies a force that opposes motion of the slider. Also, a tongue  226  is defined that cooperates with a corresponding element in the housing to create a recess that substantially restricts the movement of the resilient element  248  to the longitudinal direction. Finally, each slider  214  defines an opening  228  configured and arranged to receive a portion of the bail  212 , as discussed below. As suggested earlier herein, the bail  212  generally causes motion of the sliders  214  such that the module  200  can be latched to, and unlatched from, the port  300 . 
   Turning now to  FIGS. 4A and 4B , details are provided concerning an exemplary implementation of the bail  212  such as may be employed in connection with the operation of the sliders  214 . As indicated in those Figures, the bail  212  includes a handle  230  that connects opposing arms  232 . Each of the arms  232  includes an inner pin  234  and outer pin  236 , where the inner pins  234  are generally configured and arranged to interact with corresponding structure of the module housing  202 , while the outer pins  236  are configured and arranged to be operably received within the corresponding openings  228  defined by the pair of sliders  214  (see FIG.  3 B). As discussed in further detail below, the offset arrangement of each inner pin  234  with respect to the adjacent outer pin  236  enables rotational motion of the bail  212  to be converted into substantially linear motion of the sliders  214 . 
   In the illustrated embodiment of bail  212 , the handle  230  and arms  232  are formed as a single part. This arrangement has the benefit of reduced assembly cost and increased mechanical robustness. Additionally, the cross-sectional shape of the handle  230  is easy for the user to grip, permitting extraction of the module from the port  300 . The flat top surface of the handle  230  also provides for the possible application of graphic elements. Of course, an integral, or one-piece, bail is only one possible design. Bails consisting of multiple parts, such as a bail with arms discrete from, and joined to, the handle, may alternatively be employed. 
   With attention now to  FIG. 5 , which illustrates aspects of the underside of the module with the bottom cover  202 B removed, details are provided concerning various aspects of the module  200  structure, specifically, the sidewalls  202 A, as such relate to the structure and operation of bail  212  and sliders  214 . In particular, the sidewall  202 A defines a recess  238  generally configured and arranged to slidingly receive a substantial portion of the slider  214 . Proximate the recess  238 , a lower guide slot  240 A (see  FIG. 6C ) is defined in the bottom cover  202 B that is configured and arranged to slidingly receive the lower guide portion  220  of the slider  214 . A corresponding upper guide slot  240 B is implemented by the module housing  202  that is configured and arranged to slidingly receive the upper guide portion  220  of the slider  214 . Further, each sidewall  202 A defines a wall  242  disposed at one end of the recess  238  and defining a further recess  244  in communication with the recess  238 . Among other things, the wall  242  creates a barrier that prevents the latched module from being inadvertently extracted from the port  300 , while the recess  244  is configured and arranged to slidingly receive the ramp  216 , as necessitated by changes to the positioning of the slider  214  implemented by way of the bail  212 . 
   Additionally, a recess  246  is defined that is configured and arranged to receive the step  224  of the slider  214 . The recess  246  also receives a resilient element  248  (see FIGS.  7 A and  7 B). Finally, a substantially vertical slot  250  is defined that is configured and arranged to receive inner pin  234  of bail  212 . Generally, the inner pin  234  rotates, and slides vertically, within the vertical slot  250  in correspondence with the motion of bail  212  between various positions. As a result of this arrangement, the position of the slider  214  is entirely defined by, and limited by, the relative position of the bail  212 . 
   Directing attention to  FIGS. 6 through 6C , further details are provided concerning the disposition of the bail  212  and slider  214  with respect to the sidewall  202 A of the module  200 . Generally,  FIG. 6  depicts the module  200  as the module  200  would appear with the bail  212  in a substantially vertical position and the module  200  latched into the port  300  (not shown), while sections  6 A through  6 C indicate various specific aspects of the arrangement of the slider  214  when the module  200  is so disposed. With particular reference first to  FIG. 6A , the bail  212  is arranged so that the inner pins  234  are each received in corresponding slots  250  so that the inner pins  234  are able to rotate, and vertically slide, within the slots  250 . The outer pins  236 , positioned above the inner pins  234  when the bail  212  is oriented as shown are, as noted earlier, rotatably received within the openings  228  defined by the opposing arms  232  of the bail  212 . 
   Of course, other arrangements are possible. For example, in one alternative embodiment, the nature of the connection between the bail  212  and the slider  214  may be reversed such that the bail  212  defines the openings  228 , while the slider  214  includes the outer pins  236  received within the openings  228 . 
   While further details are provided elsewhere herein concerning operational aspects of embodiments of the invention, a downward rotational motion of the bail  212 , for example, generally causes the inner pins  234  to rotate in slots  250 , as well as move upward in slots  250 . At the same time, the rotation of the bail  212  causes outer pins  236  to translate the sliders  214  in a direction away from the host device (not shown). 
   With reference now to  FIG. 6B , additional details are provided concerning aspects of the arrangement of the bail  212  and slider  214  with respect to the sidewall  202 A of the module  200 . In particular, the step  224  and tongue  226  of the slider  214  are disposed within the recess  238  defined in the sidewall  202 A. As indicated earlier herein, the tongue  226  of each slider  214  facilitates, among other things, the confinement of a corresponding resilient element  248 . 
   As shown in  FIG. 6C , the upper and lower guide portions  220  of the slider  214  are slidingly received within the upper guide slot  240 B and lower guide slot  240 A of the sidewall  202 A. Among other things, this arrangement permits sliding linear motion of the slider  214  in response to motion of the bail  212 . 
   It was noted earlier herein that the resilient elements  248  facilitate various functionalities concerning the operation of the bail  212  and corresponding motion of the slider  214 . With attention now to  FIGS. 7A and 7B , such functionalities will be considered in further detail. In particular, the resilient elements  248  are configured and arranged to act upon the slider  214  in such a way as to bias the slider  214  toward the latched position, as indicated in FIG.  7 B. Correspondingly, the resilient elements  248  tend to resist motion of the bail  212  into a position, such as that illustrated in  FIG. 7A , where the module  200  is unlatched from the port  300 . 
   In this way, the resilient elements  248  contribute to the secure retention of the module  200  within the port  300 . Because the position of the sliders  214  and, thus, the position of the module  200  relative to the port  300 , is primarily a function of the relative position of the bail  212 , the resilient elements  248  serve to improve the user feel of the module  200  by masking deficiencies that may exist in the fit of the latch components and preferentially biasing the bail  212  into the latched and unlatched positions. Thus, one aspect of this exemplary implementation is that the motion of the bail  212  positively moves the sliders  214  between the latched and unlatched positions allowing the resilient elements  248  to be selected for feel rather than to provide a specific mechanical action. Generally, aspects such as, but not limited to, spring force, spring constant, spring bias, mechanical clearances, and configuration and positioning of the tongues  226  may be selected as necessary to suit the requirements of a particular application. 
   With respect to the exemplary implementations illustrated in the Figures, it should be noted that such implementations are not intended to limit the scope of the invention in any way. More generally, any other structure(s) and/or arrangements thereof that serve to implement comparable functionality may alternatively be employed. 
   II. Exemplary Operational Aspects of an Implementation of the Invention 
   Directing attention now to  FIGS. 8A through 8D , and with continuing attention to  FIGS. 1 through 7B , details are provided concerning various operational aspects of an exemplary implementation of the invention. As noted earlier herein, exemplary embodiments of the module  200  are configured so that the resilient elements  248  (not shown) act to bias the bail  212  into the position indicated in  FIG. 8A , that is, a position where the module  200  is releasably locked into, or latched to, the port  300  by the presence of the resilient tab  304  (see, e.g.,  FIG. 2D ) in the recess  218  collectively defined by the sidewall  202 A of the module  200  and the slider  214 . More particularly, when the module  200  is positioned in the port  300  in this way, the resilient tab  304  is biased into the recess  218  and bears on the wall  242  so as to prevent retraction of the module  200  from the port  300  (see, e.g., FIG.  2 D). 
   When it is desired to retract the module  200  from the port  300 , the bail  212  is rotated from the vertical position indicated in  FIG. 8A , through the position indicated in  FIG. 8B , and into the position indicated in FIG.  8 C. As generally discussed above, such rotary motion of the bail  212  corresponds to a retraction of the slider  214  in a direction away from the port  300 . More particularly, rotation of the bail  212  in the direction collectively indicated by  FIGS. 8A through 8C  causes the inner pins  234  (see, e.g.,  FIG. 6A ) to rotate and move upwardly in slots  250 , thereby enabling retraction of the slider  214 . 
   Thus, the offset arrangement of the inner pins  234  with respect to the outer pins  236  is such that rotation of bail  212  changes the horizontal distance between the inner pins  234  and outer pins  236 . The interaction of the outer pins  236  with the openings  228  of the sliders  214  enables motion of the bail  212  to occur in such a way that the slider  214  experiences only linear motion. Further, the lower guide slot  240 A and upper guide slot  240 B, wherein the upper and lower guide portions  220  of the slider  214  are slidingly received, also serve to facilitate achievement of this result. 
   As the sliders  214  are retracted as described above, the respective ramps  216  are retracted as well. As the ramps  216  are retracted, each ramp  216  moves out of the corresponding recess  244  and engages the leading edge of the corresponding resilient tab  304  of the port  300 . As this motion of the ramp  216  continues, the leading edge of the resilient tab  304  slides upward along the curved surface of the ramp  216  until the ramp  216  is disposed behind, and in contact with, the resilient tab  304  (see, e.g., FIG.  2 B). 
   Continued retraction of the ramp  216 , under the influence of the bail  212 , causes the ramp  216  to push outwardly on the resilient tab  304 , thereby countering the bias of the resilient tab  304 , until the resilient tab  304  is moved out of the recess  218  collectively defined by the slider  214  and sidewall  202 A (see, e.g., FIG.  2 B). Movement of the resilient tabs  304  out of the corresponding recesses  218  in this way thus unlatches the module  200  from the port  300  and thereby enables ready retraction of the module  200  from the port  300 . 
   With the bail positioned as shown in  FIG. 8C  the module  200  may be extracted from the port  300  by pulling on the handle  230 . Once the module  200  has been removed from the port  300 , the resilient elements  248  act to bias the bail  212  into the latched position indicated in  FIG. 8A  or, alternatively, the unlatched rest position indicated in FIG.  8 D. Reinsertion, and securement, of the module  200  in the port  300  can then be readily accomplished. In particular, with the bail in the latched position, the module  200  is inserted into the port  300  until the resilient tabs  304  are seated in the corresponding recesses  208  of the module  200 . 
   Thus, embodiments of the invention implement an effective, reliable and secure latch mechanism that is sufficiently compact to be implemented in connection with modules conforming to the XFP standard, while also permitting enhanced port density. Embodiments of the invention may be implemented in connection with modules conforming to various other standards as well. 
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.