Patent Document

BACKGROUND OF THE INVENTION  
       [0001]     This invention relates to a pluggable transceiver module for use in a fiber optic switch.  
         [0002]     Fiber optics are increasingly used for transmitting data signals. Typically, when data is transmitted by an optical network, it must be converted from an electrical signal to a light signal, and visa versa. In order to effectuate the conversion between electrical and optical signals, a transceiver module is used at both ends of a fiber optic cable. Each 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 back into electrical signals.  
         [0003]     Typically, a transceiver module is electrically interfaced with a host device, such as a host computer, switching hub, network router, switch box, computer I/O or the like. In many applications is it desirable for the transceiver modules to be “hot-pluggable,” that is, the transceiver module may be inserted into and removed from the host system without removing electrical power. In this way, if a transceiver module fails, it can more readily be removed from the host device and replaced with a new module without soldering or the like.  
         [0004]     Consequently, several pluggable transceiver module designs and standards have been introduced in which a pluggable transceiver module plugs into a receptacle which is electronically connected to a host circuit board. For example, such a standard is delineated in the Small Form-Factor Pluggable (SFP) Transceiver Multi-Source Agreement (MSA), dated Sep. 14, 2000. Such standards define a receptacle or cage that receives a transceiver module. The cage includes a cage latch. The transceiver module includes a latch boss which fits into the cage latch. The transceiver module also includes an actuator configured to engage the cage latch and deflect the cage latch away from the latch boss, thereby releasing the transceiver module from the cage. An exposed feature of the transceiver module is color coded to indicate if the transceiver module is multi-mode or single mode.  
         [0005]     Typically, fiber optic components use color to designate mode (e.g., wavelength, contact type, product type, etc.), or in specific applications to designate user-specific information. Transceiver modules are generally small, with only a small portion of transceiver module visible when installed. The transceiver modules are also often installed in hard to access areas. It is difficult, therefore, to ensure that the mode designation color is visible to the user. Previously, color designation has been accomplished by, for example, manufacturing the entire assembly out of a single color material (typically a plastic), manufacturing the entire front of the module out of a single color material, or providing colored handles. However, manufacturing an entire assembly or significant portion thereof out of a single color material limits the usefulness of the assembly, as components of a particular color can only be used with a particular mode. In addition, to provide the necessary strength and visibility, plastic components are typically larger than would be preferred and add unwanted size to the device. Also, for some applications it is desirable to form components from materials which is not easily colored (such as metal for EMI shielding). Finally, although various standards have been given for the configuration of the transceiver module and the cage, variations between manufacturers exist as to some of the specific configurations. The variations between manufacturers are sometimes intended to satisfy different end-user requirements, such as how the transceiver is extracted from the cage. Consequently, some configurations of transceiver modules do not utilize components such as handles, making a color designating handle feature of no advantage. It is therefore desirable to have a color mode indicator that does not add to the size of the transceiver module, and that is easily adaptable and usable with different configurations of modules without requiring different tooling, molds, components, etc.  
       SUMMARY OF THE INVENTION  
       [0006]     A mode indicator for use with a transceiver module comprises a colored plastic button having an engagement feature configured for attachment to a corresponding transceiver module engagement feature. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a perspective illustration of a transceiver module in accordance with the present invention plugged into a cage mounted on a printed circuit board.  
         [0008]      FIG. 2  is an exploded perspective illustration of the transceiver module.  
         [0009]      FIG. 3  is a perspective illustration of the housing of the transceiver module.  
         [0010]      FIG. 4  is a perspective illustration of the cage for receiving the transceiver module.  
         [0011]      FIG. 5  is an enlarged perspective view of the actuator wedge used in one configuration of the transceiver module.  
         [0012]      FIG. 6  is a bottom plan illustration of the assembled transceiver module.  
         [0013]      FIG. 7  is a perspective illustration of a release handle being used to remove the transceiver module from the cage.  
         [0014]      FIGS. 8A and 8B  are perspective illustrations of a release tool used to remove the transceiver module from the cage.  
         [0015]      FIGS. 9A and 9B  are enlarged perspective views of the mode indicator button used with the transceiver module. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.  
         [0017]      FIG. 1  illustrates transceiver module  10 , face plate  11 , cage  12 , and printed circuit board (PCB)  14  in accordance with the present invention. Cage  12  is shown mounted to PCB  14 . Cage  12  can be secured to PCB  14  in various ways consistent with present invention. Face plate  11  is fixed the PCB  14  and typically includes a plurality of openings. Cage  12  is illustrated extending through one of the openings in face plate  11 . Cage  12  may be further secured to faceplate  11  with outwardly-extending prongs or springs or the like. Only a single cage  12  is illustrated extending through faceplate  11  for ease of illustration, but one skilled in the art will recognize that a multiplicity of cages can be mounted to PCB  14  and extend through faceplate  11  to receive a multiplicity of transceivers in accordance with the present invention.  
         [0018]     Cage  12  includes cage latch  16 . In  FIG. 1 , transceiver module  10  is shown inserted into cage  12  and secured by cage latch  16 . Cage latch  16  is resiliently biased to move toward transceiver module  10  thereby securing transceiver module  10  within cage  12 . Cage latch  16  can also be moved away from transceiver module  10  so that transceiver module  10  can be extracted from cage  12 , as will be described in more detail below.  
         [0019]     Transceiver module  10  includes input/output receptacles  20  in its front face  21 . Input/output receptacles  20  may be used to provide both input and output for optical and electrical signals to and from transceiver module  10 . In other embodiments, one or more input/output receptacle  20  may be used. Front face  21  of transceiver module  10  is referred to as being at the front of transceiver module  10 . However, in this regard, such directional terminology is used with reference to the orientation of the Figures being described and is in no way meant to be limiting. One skilled in the art will recognize that components of embodiments of the present invention can be positioned in a number of different orientations.  
         [0020]     In operation, optical and electrical signals can be transmitted to and from a destination or source that is plugged into input/output receptacles  20  to transceiver module  10 . When transceiver module  10  is plugged into cage  12 , it is in electrical communication with PCB  14  via the connections therebetween. Thus, signals can be sent to and from the PCB via transceiver module  10 . Transceiver module  10  is hot pluggable and may be removed from cage  12  and replaced.  
         [0021]      FIG. 2  illustrates an exploded isometric view of the top-front side of a first configuration of transceiver module  10 . Transceiver module  10  includes housing  22  which receives transceiver opto-electronic components  24  and electromagnetic interference (EMI) shield  26 . In the first configuration of transceiver module  10 , release handle  27  and actuator wedge  28  are attached to housing  22  in manners described in greater detail below. A mode indicator button  30  is attached to housing  22  to indicate the particular mode of transceiver module  10 . Module cover  32  is configured to fit over housing  22  of transceiver module  10  and protects opto-electronic components  24 . Module cover  32  also helps secure module  10  in cage  12  when it is inserted therein, and also helps secure release handle  27  and actuator wedge  28  to housing  22 .  
         [0022]     In one embodiment, housing  22  is formed of a die cast or molded conductor, such as metal or conductive plastic, while module cover  32  is formed from stamped and shaped sheet metal. Release handle  27  is formed of shaped wire, while wedge  28  and mode indicator button  30  are formed of a plastic material.  
         [0023]     In a second configuration of transceiver module  10 , the same housing  22 , opto-electronic components  24 , EMI shield  26 , mode indicator button  30  and module cover  32  are utilized, but release handle  27  and actuator wedge  28  are omitted from transceiver module  10 . In this manner, different end-user configuration requirements for the transceiver module  10  can be satisfied with common components. In particular, housing  22  can be used for at least two different transceiver module configurations.  
         [0024]     As best seen in  FIG. 3 , the bottom side of housing  22  provides a surface  33 . A latch boss  34  extends away from surface  33  such that the top of latch boss  34  is raised relative to surface  33 . Latch boss  34  extends away from surface  33  and is configured to engage cage latch  16  of cage  12  (best seen in  FIG. 4 ). Specifically, when transceiver module  10  is inserted into cage  12 , latch boss  34  deflects latch  16  slightly away from transceiver module  10  such that latch boss  34  travels past the front edge  36  of latch  16  and toward latch slot  40  in latch  16 . When transceiver module  10  is fully inserted into cage  12 , latch boss  34  is aligned with latch slot  40  such that latch boss  34  extends through latch slot  40 . Latch  16  is configured with a bias such that when latch boss  34  is fully aligned with latch slot  40 , latch  16  transitions toward transceiver module  10 . In this way, transceiver module  10  will be locked into cage  12 .  
         [0025]     In one embodiment, latch boss  34  and latch slot  40  are configured to be triangular in shape and complement each other such that latch boss  34  fits through latch slot  40 . Although latch slot  40  is specified as triangular in shape in the above-referenced Small Form-Factor Pluggable Transceiver Multi-Source Agreement, latch boss  34  and latch slot  40  may have shapes other than the triangular shape illustrated in the Figures. The shapes of latch boss  34  and latch slot  40  may be the same (i.e., both triangular, rectangular, circular, etc.), or may be different, so long as latch slot  40  is capable of securely engaging latch boss  34 .  
         [0026]     In the first configuration of transceiver module  10 , release handle  27  is mounted in trough  37  or similar openings on housing  22 . Handle  27  is mounted in trough  37  such that it can be rotated relative to transceiver module  10 . Release handle  27  includes cam portion  39 . As described in greater detail below, when handle  27  is rotated, cam portion  39  engages actuator wedge  28  and causes wedge  28  to move away from front face  21  of transceiver module  10 . In one embodiment (best seen in  FIG. 5 ), tab portions  43  of module cover  32  trap handle  27  within trough  37  when module cover  32  is installed on housing  22 .  
         [0027]     In the first configuration of transceiver module  10 , actuator wedge  28  (seen in  FIGS. 2, 5  and  6 ) is slidably retained in a slot (shown as T-slot  42 ) that is provided on surface  33 . Slot  42  is configured to retain actuator wedge  28  such that wedge  28  can move toward and away from the front side  21  of transceiver module  10 , but so that it cannot move laterally. The engaging shapes of actuator wedge  28  and slot  42  may differ from the T-shape illustrated, so long as slot  42  retains actuator wedge  28  adjacent surface  33  and permits wedge  28  to move toward and away from the front side  21  of transceiver module  10 , but constrains lateral movement of actuator wedge  28 .  
         [0028]     Actuator wedge  28  includes tines  44  spaced to accommodate latch boss  34  therebetween, such that when latch boss  34  is placed between tines  44 , as illustrated in the Figures and described in greater detail below, linear movement of wedge  28  (in the direction of arrow  45  in  FIG. 6 ) will not be impeded by latch boss  34  as wedge  28  moves away from the front face  21  of transceiver module  10 . Tines  44  of wedge  28  are configured with ramp portions  52 . As wedge  28  moves away from the front face  21  of transceiver module  10 , ramp portions  52  of tines  44  engage latch  16  of cage  12  and deflect latch  16  away from surface  33  of module  10 . Ramp portions  52  are illustrated as having a generally linear slope, but can also be designed with non-linear slopes.  
         [0029]     To extract transceiver module  10  from cage  12 , cage latch  16  must be moved away from surface  33  of transceiver module  10  a sufficient distance so that that latch slot  40  is removed from engagement with latch boss  34  and latch boss  34  clears the front edge  36  of latch slot  40 , as will be described more fully below.  
         [0030]     In the configuration of transceiver module  10  having release handle  27  and actuator wedge  28 , the release handle  27  can be used to release transceiver module  10  from cage  12  so that it can be extracted therefrom. In  FIGS. 1 and 6 , release handle  27  is shown in a closed or 0° position, such that it is generally parallel with the front face  21  of transceiver module  10 . In one embodiment, cam portion  39  of release handle  27  does not engage wedge  28  when release handle  27  is in the closed postion. As release handle  27  is rotated from the initial closed position toward a second open position (best seen in  FIG. 7 ), cam portion  39  moves away from the front of transceiver module  10  with the rotation, thereby engaging actuator wedge  28  and causing actuator wedge  28  to move in an approximately linear direction within slot  42  away from the front face  21  of transceiver module  10  with the rotation of release handle  27 .  
         [0031]     As wedge  28  moves away from front surface  21 , ramp portions  52  of wedge  28  engage cage latch  16  and deflect latch  16  away from surface  33  of transceiver module  10  and consequently away from latch boss  34 . In this way, the movement of wedge  28  against latch  16  pushes latch  16  off latch boss  34  and provides clearance for latch boss  34  to pass out of latch slot  40 . Once adequate clearance is provided, transceiver module  10  can be removed from cage  12 , such as by pulling on handle  27 .  
         [0032]     In the configuration of transceiver module  10  in which release handle  27  and wedge  28  are not present, release tool  60  (illustrated in  FIGS. 8A and 8B ) can be used to release transceiver module  10  from cage  12  so that it can be extracted therefrom. Release tool  60  includes a handle portion  61  having connector engagement elements  62  at one end thereof. Engagement elements  62  are configured to engage receptacles  20  of transceiver module  10 . Actuator arm  64  extends past connector engagement elements  62  and is shaped to approximately resemble wedge  28  at its distal end  66 . Accordingly, similar reference numbers are used herein to designate similar parts. As described above with respect to wedge  28 , when actuator arm  64  is actuated, such as by inserting the tool, ramp portion(s)  52  engages latch  16  of cage  12  and deflect latch  16  away from surface  33  of module  10 .  
         [0033]     To remove transceiver module  10  using release tool  20 , actuator arm  64  is inserted through gap or opening  70  in front face  21  of housing  22 . Opening  70  is sized to receive actuator arm  64  and permit actuator arm  64  to pass unimpeded through slot  42 . From this first position, as removal tool  60  is advanced toward transceiver module  10 , connector engagement elements  62  engage receptacles  20 , and ramp portions  52  of actuator arm  64  engage cage latch  16 . Ramp portion(s)  52  deflect latch  16  away from surface  33  of transceiver module  10  and consequently away from latch boss  34  to provide clearance for latch boss  34  to pass out of latch slot  40 . Once actuator arm  64  of removal tool  60  is fully inserted and adequate clearance is provided, transceiver module  10  can be removed from cage  12 , such as by pulling on handle portion  61  of removal tool  60 .  
         [0034]     Actuator arm  64  of removal tool  60  is illustrated as spatially fixed with respect to handle portion  61  and connector engagement elements  62 , such that connector engagement elements  62  engage receptacles  20  of transceiver module  10  concurrent with the engagement of actuator arm  64  and latch  16 . In other embodiments, actuator arm  64  may be movable with respect to handle portion  61  and connector engagement elements  62 , such that connector engagement elements  62  engage receptacles  20  of transceiver module  10  prior to the engagement of actuator arm  64  and latch  16 .  
         [0035]     Typically, fiber optic components use color to designate mode (e.g., wavelength, contact type, product type, etc.). Transceiver module  10  is generally small and only a small portion of transceiver module  10  is visible when installed in cage  12 . Mode indicator button  30  ( FIGS. 2, 9A  and  9 B) provides a highly visible color signal adjacent the front face  21  of transceiver module  10 , and is visible from the front and top of transceiver module  10 . Mode indicator button  30  is a molded plastic button (in any desired color) that is integral to the fiber optic input/output receptacles  20  of transceiver module  10 , thereby clearly providing mode information to a user and adding no size to transceiver module  10 . In one embodiment, mode indicator button  30  includes a recessed portion  80  in its back surface that is shaped to receive protrusion  81  of housing  22 . Mode indicator button  30  may be secured to protrusion  81  by means including press fit and adhesive. In another embodiment, the positions of recessed portion  80  and protrusion  81  may be switched such that mode indicator button  30  has a protrusion receivable in a recessed portion of housing  22 .  
         [0036]     Mode indicator button  30  can be used to designate transceiver module  10  optical mode information, or in specific applications can be used by the end-user to designate user specific information. Mode indicator button  30  provides several advantages over previous color marking features, such as color coded molded handles. For example, mode indicator button is easily assembled for different mode configurations, adds no size to the transceiver module, and allows the use of either a handle  27  or a removal tool  60  to release the transceiver module  10  from cage  12 . Previous color marking features, such as color coded molded handles, are obviously of no advantage in a transceiver module with no handle.  
         [0037]     Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Those with skill in the mechanical, electromechanical, and electrical arts will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the preferred embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Technology Category: g