Abstract:
A system and method to facilitate receipt of an optoelectronic module in a first direction and make an electrical connection by movement of the module in a second direction different from the first direction.

Description:
FIELD OF THE INVENTION 
   The present invention relates to electrically connecting an opto-electronic module to a printed circuit board. 
   BACKGROUND 
   Opto-electronic modules are modules that transmit and/or receive data optically, for example, using lasers or receivers. An optical connector of some type provides for data passage between the optical devices in the module and other optical components. Typically, such modules also send and/or receive electrical signals, for example, via an electrical connector on a printed circuit board or a backplane. In general, an optical device, which is found in the module, requires several electrical connections. Due to the large number of optical devices that may be present in the module, the number of electrical connections can be numerous. Thus, depending upon the number of optical devices, for space considerations the electrical connector can be configured as a linear or, for a larger of number of optical devices, a two-dimensional array. 
   In instances where multiple modules are used, they are typically configured in front loading rack-mount systems, which contain racks for receiving modules in much the same way as the frame of a household dresser receives a drawer. Connectors mounted on a backplane at the rear of the drawer or rack mate with connectors mounted on the modules when the modules are seated. Since each rack can contain from a few to hundreds of modules, for ease of maintenance it is important that each module can be serviced (i.e. inserted or removed) independent of as many, preferably every, other module(s) because each unrelated module that must be disrupted in the course of servicing another represents lost capability and, accordingly, potential loss of time and/or revenue. As a result, modules are configured so that they can be inserted and removed through the front panel of the front loading rack-mount system to avoid having to disengage the rack from the backplane and thereby potentially disrupt the operation of one or more unaffected modules. 
   As the demand for optical communication capability increases, the need for greater numbers of optical devices will similarly increase. However, as noted above, greater numbers of optical devices generally result in larger modules and much larger electrical connectors. Hence, the number of modules that can be fit within a given size front loading rack-mount system decreases. Moreover, since the size of the connector (due to increased numbers of pins or other contact elements) grows faster than the number of devices, the ability to fit more modules within a given size front loading rack-mount system quickly becomes limited by the connector size. 
   For example,  FIG. 1  shows an exemplary opto-electronic module  100  of the prior art. The module  100  has an optical connector  110  on its front side  120  providing access to, in this example, twenty-four optical devices (not shown) such as lasers and/or photoelectors and an electrical connector  130  on its back side  140 . The electrical connector  130  is configured to pass through the front panel  170  of the rack (not shown) in order to mate with a complementary connector  150  on a circuit board or a backplane  160  at the rear of the rack. Thus, for ease of maintenance, the connection between the module  100  and the backplane  160  is made by insertion of the module  100  longitudinally through the front panel  170  towards the backplane  160  until the two connectors  130 ,  150  mate. 
     FIG. 2  shows the module  100  of  FIG. 1  following mating of the two connectors  130 ,  150  in the above described manner. 
     FIG. 3  is a rear view of the module  100  of  FIG. 1  so that the electrical connector  130  is visible. The electrical connector  130  has an array  180  of pins  190  through which electrical signals can pass between the module  100  and the backplane  160 . As noted above, and as is typically the case, the size of the electrical connector on the back side is much larger and contains many more pins than the number of optical devices. Thus, it will be recognized that a mere doubling of the number of optical devices in this example to forty-eight may result in no change in the overall of the module  100  but may require a connector approaching twice the illustrated overall area and thereby far exceed the overall area taken up by the back of the module. As a result, for a given size drawer, the crossover point between increased devices per module versus total number of modules that can be accommodated can shift to a net loss quite quickly. 
   Thus, there is presently no easy way, for a given size front panel accessible drawer of a rack and a given size and number of modules, to substantially increase the number of optical devices. 
   SUMMARY OF THE INVENTION 
   We have recognized that, because the bottom of the module has a larger surface area than the rear of the module (i.e. it can accommodate a larger connector within its boundaries), moving the connector to the bottom of the module solves part of the problem. However, since the electrical connector is then actually or substantially perpendicular to the optical connector, movement of the electrical connector to the bottom detrimentally affects front panel accessibility, since longitudinal insertion of the module through the front panel does not allow for making the electrical connection because it requires movement of the module in a direction other than the direction of insertion. Advantageously, we have developed a way that allows such modules (i) to be used in a front loading rack despite the electrical connector being on the bottom of the module, and (ii) make the electrical connection. As a result, the bottom connector modules can still be independently serviced while causing minimum, and in many cases no disruption to surrounding modules. Through use of a device that receives the module through the front panel (for example, in a plane defined by the module&#39;s electrical connector) and can then move the module in the direction necessary to make the electrical connection (for example, substantially perpendicular to the plane defined by the module&#39;s electrical connector) the above problems are addressed. 
   The above advantages and features are of representative embodiments only, and are presented only to assist in understanding the invention. It should be understood that they are not to be considered limitations on the invention as defined by the claims, or limitations on equivalents to the claims. For instance, some of these advantages may seem mutually contradictory, in that they cannot be simultaneously implemented in a single embodiment. Similarly, some advantages are primarily applicable to one aspect of the invention. Thus, this summary of features and advantages should not be considered dispositive in determining equivalence. Additional features and advantages of the invention will become apparent in the following description, from the drawings, and from the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an exemplary opto-electronic module of the prior art; 
       FIG. 2  shows the module of  FIG. 1  following the mating of two connectors; 
       FIG. 3  is a rear view of the module of  FIG. 1  so that the module&#39;s connector is visible; 
       FIG. 4  shows a simplified example of an opto-electronic module configured for use in accordance with the present invention; 
       FIG. 5  shows, for example, the implementation of a device suitable for use with the present invention; 
       FIG. 6  is a simplified front view of an opto-electronic module seated in a frame similar to that shown in  FIG. 5  in accordance with the present invention; 
       FIG. 7  is a front view of the opto-electronic module of  FIG. 6  following the mating of two connectors in accordance with the present invention; 
       FIG. 8  is a front view of an example rack from a front loading rack-mount system implementing the present invention with its front panel in place; 
       FIG. 9  is a partial internal view of the rack of  FIG. 8  with its front panel removed; 
       FIG. 10  shows an alternative variant in accordance with the present invention; 
       FIG. 11  shows another alternative variant in accordance with the present invention; 
       FIG. 12  shows yet another alternative variant in accordance with the present invention; 
       FIG. 13  shows another alternative variant in accordance with the present invention; 
       FIG. 14  shows another alternative variant in accordance with the present invention; 
       FIG. 15  shows a further variant in accordance with the present invention; 
       FIG. 16  shows another variant in accordance with the present invention; and 
       FIG. 17   a  through  17   c  show simplified examples of opto-electronic modules suitable for use with the present invention. 
   

   DETAILED DESCRIPTION 
   In general, a device is used that receives the opto-electronic module through the faceplate of the rack drawer (e.g. in a plane defined by the module&#39;s electrical connector) and then moves the module in a direction substantially perpendicular to the plane of the electrical connector to connect the module to the printed circuit board. This approach enables an increasing number of opto-electronic devices to be contained in the opto-electronic module (due to the additional area provided by positioning the electrical connector at the bottom of the module) while still providing insertion and removal of the module through the front panel of a front loading rack-mount system. Moreover, the number of devices is only limited by the area defined substantially by the width of the module and the depth of the rack drawer (i.e. the frontal area can remain the same but the electrical connector size can be increased depth-wise until a limit related to the depth of the rack is reached). 
     FIG. 4  shows a simplified example of an opto-electronic module  400 , for example, an opto-electronic transmitter, receiver or transceiver configured for use in accordance with the present invention. As shown in  FIG. 4 , the opto-electronic module  400  is oblong in shape and also contains various optical and electronic components (not shown because the details are unimportant for understanding the invention). The module  400  includes a body  410 . The module  400  also includes an optical connector  420  and an electrical connector  430  positioned such that they define a pair of planes substantially perpendicular to one another. The electrical connector  430  is configured for mating with a complementary electrical connector located on, for example, a printed circuit board. The module  400  further includes at least one guide structure  440 , shown for purposes of example, in the form of a rail positioned on a side of the body  410 . 
   By way of background, the optical connector  420  is the interface through which optically encoded data signals pass when transiting between the module  400  and elsewhere. 
   If optically encoded data signals are received by the module  400  through the optical connector  420 , they are converted into electrical signals (by the module&#39;s  400  internal components) and, in some cases, are further transmitted electrically elsewhere via the electrical connector  430 . 
   Similarly, if electrically encoded data will be transmitted optically by the module  400 , it is received by the module  400  via the electrical connector  430 . The data is then converted to optically encoded data within the module before being transmitted from the module  400  via the optical connector  420 . 
   In the case of a transceiver, the optical connector  420  and the electrical connector  430  together provide for the bi-directional transmission of data through the module  400  as described above. 
     FIG. 5  shows, by way of example, one example implementation of a device suitable for use with the present invention. A frame  500  has an opening on its front for receiving a module and two guides  515 , one on each side, configured to accept a complementary pair of guides of an opto-electronic module. The frame  500  is configured to also move in a direction other than that of module insertion, for example, slidably along several posts  560 . As shown in this example, the posts  560  are perpendicular to the plane of the frame  500  and are encircled by springs  540  that urge the frame  500  into a normally disengaged position, for this implementation, that is away from the printed circuit board  505 . To prevent the guides  515  from being urged off the posts  560  by the force of the springs  540  if necessary, a retaining clip or pin  545  is provided at the top of at least one of the posts  560 . 
   The frame  500  of  FIG. 5  is also coupled to a lever  520  that moves the frame  500  from a normally disengaged position to an engaged position. The lever  520  is connected to the frame  500  by a pin through a slot  555  in the lever  520  or some other suitable known manner. A lock  550  is optionally provided to secure the lever  520  when the lever  520  is in an engaged position. Optionally, the frame  500  may also or alternatively include alignment features, for example, one or more alignment boss(es)  530  or alignment pin(s). One or more complementary elements, for example, tapered pins  525 , on the circuit board  505  can be used to engage the, in this example, bosses(es)  530  to, in different implementations, act as stops for when the frame  500  is in an engaged position and/or assist in alignment by forcing the frame into a particular position in the X-Y plane. 
   In general, the frame is configured to move an opto-electronic module in a direction other than the direction of the module&#39;s insertion so that its electrical connector will mate with its complementary electrical connector. Thus, for the example of FIG.  4  and  FIG. 5 , the process of mating the two electrical connectors  430 ,  510  proceeds as follows. The module  400  of  FIG. 4  is inserted into the frame  500 . By aligning the guide  440  with the complementary guide  515  in the frame  500  and, then longitudinally inserting the module  400  through the front panel into the frame  500 , in this example, along a plane defined by the electrical connector  430  so that it becomes secured in the frame  500 . The guide  440  of  FIG. 4  is thus used to align, constrain and control insertion of the module  400  into the frame  500 . Once the module  400  is fully inserted into the frame  500  the lever  520  is moved downward to cause the frame  500  to move the module  400  in a direction substantially perpendicular to its electrical connector  430  to connect or disconnect the electrical connector  430  of the module  400  to the electrical connector  510  of the circuit board  505 . This movement is referred to as “substantially” perpendicular because, depending upon the implementation some pivotal, arcuate or other translational movement beyond pure perpendicular movement can also be involved. 
   As the frame  500  is moved downward, if one or more of the optional alignment bosses  530  are used, movement of the lever  520  to mate the electrical connectors  430 ,  510  will cause the alignment bosses  530  to act in conjunction with the tapered pins  525  to, in the example shown, center and thereby ensure proper x-y alignment of the electrical connector  430  relative to its complementary connector  510 . 
   Once the electrical connectors  430 ,  510  are mated, if the urging spring force is too great it can cause the electrical connectors  430 ,  510  to separate unintentionally. In such cases, a lock  550  can be optionally used to secure the frame  500  in the engaged position, for example, by constraining or clamping the lever  520 . By releasing the lever  520  from the lock  550  (i.e. unclamping the lock  550 ) the spring force alone and/or moving the lever  520  in an upward direction will cause the electrical connectors  430 ,  510  to become disengaged. 
     FIG. 6  is a simplified front view of an opto-electronic module that has been inserted through the front faceplate of a rack drawer (not shown) so it is now seated in a frame similar to that shown in  FIG. 5  in accordance with the present invention. As shown in  FIG. 6 , the opto-electronic module  600  includes an optical connector  605  on its front, an electrical connector  610  on its bottom side and two guides  615  each in the form of a rectangular rail. A frame  620  includes two guides  625  each in the form of a channel and is positioned to slidably move along at least two posts  630  each encircled by a spring  635 . The frame  620  accurately positions the electrical connector  610  over the electrical connector  650  on the circuit board  645  so that no alignment boss is required. A lock  655  is provided on the circuit board  645  to maintain the lever  640  in the lower position when the module  600  is seated and the electrical connectors  610 ,  650  are mated. 
     FIG. 7  is a front view of the opto-electronic module  600  of  FIG. 6  following the mating of the electrical connectors  610 ,  650  in accordance with the present invention. As shown in  FIG. 7 , the lever  640  has been moved downward (along the arrow  660 ) bringing the frame  620  in a downward direction to compress the springs  635  and cause the mating of the connectors  610 ,  650 . As illustrated, the lever  640  is positioned just prior to being secured by the lock  655  through slight movement to the side. Releasing the lever  640  from the lock  655  (i.e. unclamping the lock  655 ) and moving the lever  640  in the opposite direction along the arrow  660  disengages the electrical connectors  610 ,  650  and moves the frame  620  towards a position where the module  600  can be removed from the rack via the front panel. Thereafter, once the frame  620  reaches the position shown in  FIG. 6 , in order to remove the module  600 , a user need only pull the module  600  from the frame  620  and need not disturb any other adjacent or nearly module. 
     FIG. 8  is a front view of an example rack  800  from a front loading rack-mount system implementing the present invention, viewed from the front, with its front panel  805  in place. As shown in  FIG. 8 , the rack  800  includes a front panel  805  and several rows  810 ,  815 ,  820 ,  825  of slots  830 ( a . . . x ) each having frames  835 ( a . . . x ) as described above. As shown, each frame  835 ( a . . . x ) includes a lever  845 ( a . . . x ) and an optional lock  850 ( a . . . x ) similar to that described above. In general, the openings in the front panel  805  are dimensionally slightly larger than the modules  840 ( a . . . x ) to allow for clearance of the guides and unmated part of the electrical connector on each of the modules  840 ( a . . . x ). As shown, each of the modules  840 ( a . . . x ) in the lower three rows  815 ,  820   825  is seated such that their individual electrical connectors (not shown) are mated. This is nevertheless evident from the levers  845 ( a . . . x ) being secured in the downward position by the locks  850 ( a . . . x ). 
   As further shown in  FIG. 8 , the uppermost row  810  includes an empty slot  830   c , such that the frame  835   c  is visible. Another slot  830   f  contains a module  840   f  that has been disengaged so that it is ready for removal. The module  840   f  is removed by simply pulling the module  840   f  outward from the frame  835   f    
     FIG. 9  is a partial internal view of a portion of three rows  815 ,  820 ,  825  in the example rack  800  of  FIG. 8  viewed as if its front panel  805  was removed. As shown in  FIG. 9 , the electrical connectors  855 ( a . . . x ) of the modules  840 ( a . . . x ) are mated to the electrical connectors  860 ( a . . . x ) of several printed circuit boards  865   a ,  865   b ,  865   c  that would not be visible with the front panel  805  in place. In the example of FIG.  8  and  FIG. 9 , the printed circuit boards  865 ( a . . . x ) can also be removable and may, in turn, be connected to components via, for example, backplane or cabling (not shown) at the rear of this drawer of the rack  800 . 
   Although the above examples have all used guides of square cross section formed as rails, in alternative variants of the present invention, guides of different sizes, forms and shapes can be used. This, different guides can be used as a form of “keying” to ensure that only the correct modules can be inserted and/or accepted into a particular frame. In this manner, for example, it is possible to differentiate between two modules using the same physical connectors but having incompatible electrical differences, for example, reversed power and ground connections or reversed data input and output connections. Similarly, this approach makes it possible to provide a visual commonality to a family of modules while preserving a difference among individual modules in the family. For example, all modules in a particular family of modules could have a specific size and shape left side guide but be differentiated from others in the family through different and incompatible right side guides. 
     FIG. 10  shows an alternative variant in accordance with the present invention. In this example, the guides  1010 ,  1015  on the module  1000  are each still in the form of rails, but each is of a different cross sectional shape and size. Complementary guides  1005 ,  1025  in the form of channels on the frame  1030  are configured to accept the guide  1010 ,  1015  as described above. Because the guides on the left side  1005 ,  1010  and right side  1015 ,  1025  are incompatibly different with respect to each other, the module  1000  can only be inserted in the manner shown and another module, such as the module  600  of FIG.  6  and  FIG. 7 , could not be used because its left side rail  615  could not be accommodated by the channel  1005  of the left side frame  1020  of FIG.  10 . 
     FIG. 11  shows another alternative variant in accordance with the present invention. As shown in  FIG. 11 , the guides  615 ,  1110  on the module  1120  are again in the form of rails but one guide  615  is the same as in  FIG. 6  but the other guide  1110  has a triangular cross sectional shape. Thus, this configuration would not allow the module  1120  of  FIG. 11  to be used in the frames of  FIG. 6  or FIG.  10 . Similarly, neither the module  600  nor the module  1000  could be used in the frame of FIG.  11 . 
   Although the above examples in FIG.  10  and  FIG. 11  used a set of rails and complementary channels for the guides, this approach is not specifically required. Instead, for example, other elements suitable for aligning, constraining and controlling insertion of the opto-electronic module into the frame can be used, for example, posts, pins or other elements. In addition, it is to be understood that the guides need not be formed as outwardly extending pieces on the module. Instead, the module can have one or more channels with the frame having complementary elements in the form of outwardly extending rails, pins or other elements that go into the channels on a module. Advantageously, with this approach, the modules can be narrower and the opening in the front panel can be made smaller because the overall insertion footprint will be smaller. Of course, different combinations of the above can also be used, including the mixing and matching of rails, pins or grooves on modules or frames. Any manner that still achieves the constraint and placement aspects described herein can be part of an implementation of the invention. 
     FIG. 12  shows yet another alternative variant in accordance with the present invention. As shown in  FIG. 12 , the optoelectronic module  1200  includes several guides  1205 ,  1210  in the form of multiple individual posts (only those on one  1215  side being visible). The guides  1205  in the upper row are tapered posts whereas the guides  1210  in the lower row are cylindrical posts. The rows of guides  1205 ,  1210  are linearly aligned for sliding into and along complementary shaped guide slots  1220 ,  1225  in one side of the frame  1230 . 
   Just as different configurations and elements can perform the guide functions, other aspects can be changed or substituted. For example, instead of, or in addition to, using springs coiled about posts as described above other mechanisms to move the frame can be used. 
   For example, in other alternative variants of the present invention, a variety of types of springs including coil, helical, leaf and torsion springs can be used to urge the frame into a normally disengaged position. The following are a few representative illustrative examples showing, for purposes of simplification, only the relevant details. 
     FIG. 13  shows one such example alternative variant suitable for use in an implementation of the invention. As shown in  FIG. 13 , instead of using individual coil springs about the posts along which the frame moves, as described above, this variant incorporates a leaf spring  1305  located between the frame  1300  and the circuit board  1315 . In the normal position, the leaf spring  1306  is fully bowed and the frame  1300  merely rests on the top of the bowed portion. In some implementations, it may be necessary to prevent movement of the spring in undesirable directions, for example, when the spring is unloaded. This can be accomplished many different ways too numerous to name. For purposes of completeness, one simple example is provided with the understanding that others can be readily substituted without the application of anything more than a basic understanding of mechanical engineering. In the example, the ends of the spring  1305  are split to form a pair of tines, with one tine on one end being on one side of the post and the other tine on that end being on the other side of the post. As the spring  1305  is compressed, the split/tines constrain the movement to essentially only follow along the length of the split. In addition, a bent or highly curved portion  1310  near each end of the spring  1305  in conjunction with a retainer element, such as a clip, channel or flange  1320  is used to keep the spring ends from undesirable upward movement or and prevent either end from passing beyond the post. In this implementation, movement of the frame  1300  from the disengaged towards the engaged position, for example to seat a module inserted into the frame  1300 , compresses the leaf spring and causes the two ends to move away from each other such that, at the maximum compression point, the electrical connector on the bottom of an inserted module will be mated to the electrical connector  1310  on the circuit board  1315 . 
     FIG. 14  shows another example alternative variant suitable for use in an implementation of the invention using a helical coil spring  1405 . As shown in  FIG. 14 , the frame  1400  is urged into a disengaged position by the helical coil spring  1405  positioned underneath a “wing”  1410  attached to a side of the frame  1400 . 
     FIG. 15  shows yet another representative example more complex variant of a frame moving mechanism in accordance with the present invention. As shown in  FIG. 15 , a rotatable knob  1505  is coupled to gears  1510  via a shaft  1515 . A cam  1515  is configured with an appropriate profile so that, when the knob  1505  is rotated, the cam  1515  applies a force to a fixed element  1520  on the frame  1520  and thereby causes it to move down the posts  1525  and compress the springs  1535  until the peak  1530  of the cam  1515  is touching the element  1520 . At this point, when the frame  1520  contains a module, the electrical connector of the opto-electronic module will be fully coupled to the electrical connector  1310  on the circuit board  1315 . Reverse (or as shown further) rotation of the knob  1505  eases the compression of the springs  1535  and thereby causes the frame  1520  to move back toward the normally disengaged position. 
   In yet other variants of the present invention a spring need not be used at all—all that is required is some mechanism that moves the frame between the disengaged and engaged positions. For example, by movably coupling cam  1515  of  FIG. 15  to the element  1520 , an arrangement can be formed that will move the frame in the directions that cause mating and un-mating of the two electrical connectors without the use of a spring at all. 
   In addition, in some variants, the movement of the frame need not be purely linear, nor must it be in only one direction. For example, the movement could be in two linear directions so that the frame itself can be configured to slide in the plane of insertion and perpendicular to it to, for example, to cause the frame to be closer to the face plate when no module is present and thereby facilitate acceptance of a module. 
   In another example, a portion of the movement could be a pivoting or arcuate movement.  FIG. 16  shows a simplified representative further example variant of a frame moving mechanism in accordance with the present invention involving pivoting or arcuate movement in addition to movement perpendicular to the connector  1310 . 
   As shown in  FIG. 16 , the mechanism  1600  is made up of a frame  1605  configured to accept an opto-electronic module as described above. A spring  1610 , located above the frame  1605  and connected to it, is used to maintain the frame  1605  in a normally disengaged position. The rear of the frame is connected to a rear collar  1615  by a pin  1620  that allows the frame to move about the pin  1620 . The rear collar is itself movable along a post  1625  of a specified height. In addition, a flange  1630  on the collar acts as a pivot stop to prevent the frame  1605  from moving in a pivotal manner beyond a parallel to the circuit board  1315 . Near the front of the frame  1605  is another post  1640  that is taller than the rear post  1625 . Each of the front and rear posts  1625 ,  1640  have a stopper  1630  on its top to prevent the spring  1610  from pulling the frame  1605  off of the posts  1625 ,  1640 . A slot  1645  and pin  1650  arrangement couples the frame  1605  to a front collar  1655  to accommodate pivoting of the frame  1605 . The front collar  1655  is also slidably moveable along the front post  1640 . As a result, the operation of this mechanism is as follows. When a module is inserted into the frame  1605 , it is at an angle θ with respect to the connector  1310 . A lever, cam or other element (not shown) is used to apply a force to the frame  1605  that extends the spring  1610  and causes the frame  1605  (and accordingly the module) to move both in an arc and along the posts  1625 ,  1640  until, immediately before the connector on the module mates with the connector  1310  on the board  1315 , the two are parallel to each other. Depending upon the particular implementation, this may involve complete movement through an arc angle θ before any movement along the rear post  1625  occurs or some combination of movement along the post  1625  during the pivotal movement. 
   At this point it is to be understood that, for each implementation described herein, the connector on the module will be parallel to the connector on the board immediately before the two electrical connectors mate, irrespective of their orientation relative to each other at the time of module insertion through the front panel. 
   In view of all of the above, it should be appreciated that through use of the invention, much larger connectors can be used with a given size module in a given size front loading rack than was otherwise possible. This advantage is shown most clearly in the simplified modules of  FIG. 17   a  through  17   c.    
     FIG. 17   a  shows an opto-electronic module  1700  suitable for use with the invention having an electrical connector  1705 , equal in size to the rear footprint  1710  of the module  1700 , and located on its bottom side  1715 . 
     FIG. 17   b  shows a second module  1720 , identical in body size to the module of  FIG. 17   a  except it has an electrical connector  1725  that is 50% larger than the electrical connector  1705  shown in  FIG. 17   a.    
     FIG. 17   c  shows yet another opto-electronic module  1730 , also identical in body size to the module of  FIG. 17   a . However, in this case, it has an electrical connector  1735  that is significantly longer than the electrical connectors  1705 ,  1725  shown in  FIG. 17   a  and  FIG. 17   b  to the point of extending well beyond the end of the body of the module  1730 . Of course, in such a case, it may be desirable to provide a support  1740  of some sort to provide rigidity to the overhanging part of the connector  1735  and/or to act as a conduit for wiring (not shown) that is provided to pins of the electrical connector  1735  located in the overhanging portion beyond the end of the body. Should a sufficiently long connector be used such that a support  1740  must be used, in such a case, it is unimportant from the standpoint of the invention whether the support  1740  is part of, attached to, or wholly independent of body of the opto-electronic module. 
   As a result, and as shown in  FIG. 17   c , through use of the invention with a given size opto-electronic module, the size of the electrical connector is only really constrained by the total available depth of a rack (“d”) since increasing the length of the connector will not increase the insertion footprint of a given module. 
   Having described several different examples, it should be apparent that individual aspects may also be modified or implemented differently without departing from the invention to achieve additional or alternative advantages. For example, if a lock of some sort is used to constrain a module in the mated position, it need not be part of circuit board. Instead it could be part of some other component including the frame, the faceplate, or some other part of a rack drawer, to name a few. Similarly, the frame need not be affixed to the circuit board, but instead could be affixed to or part of the drawer or even could be affixed to a board, in a hanging configuration, above the connector to which the module will connect. In addition, instead of using one or more springs to urge the frame into a “normally disengaged position” one or more springs could be used to urge the frame into a normally “engaged” position, whether or not the frame contained a module. In such an arrangement, a lever, screw, cam or other element would be used to move the frame from the normally engaged position to a disengaged position so that a module could be inserted or removed. In addition, in some arrangements having a normally engaged configuration, it will be advantageous, although not necessary, to use a locking mechanism to maintain the frame in the disengaged position during module insertion or removal. 
   It should therefore be understood that the above description is only representative of illustrative embodiments. For the convenience of the reader, the above description has focused on a representative sample of possible embodiments, a sample that is illustrative of the principles of the present invention. The description has not attempted to exhaustively enumerate all possible variations. That alternate embodiments may not have been presented for a specific portion of the invention, or that further undescribed alternate embodiments may be available for a portion, is not to be considered a disclaimer of those alternate embodiments. Other applications and embodiments can be straightforwardly implemented without departing from the spirit and scope of the present invention. It is therefore intended, that the invention not be limited to the specifically described embodiments, since numerous permutations and combinations of the above and implementations involving non-inventive substitutions for the above can be created, but the invention is to be defined in accordance with the claims that follow. It can be appreciated that many of those undescribed embodiments are within the scope of the following claims, and others are equivalent.