Patent Publication Number: US-2023142093-A1

Title: Fiber optic adapters for use with fiber optic connectors and methods for coupling fiber optic connectors

Description:
PRIORITY APPLICATION 
     This application claims the benefit of priority of U.S. Provisional Application No. 63/277,729, filed on Nov. 10, 2021, the content of which is relied upon and incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to optical connectivity, and more particularly to adapters and methods for their use in coupling fiber optic connectors to fiber optic networks. 
     BACKGROUND 
     Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. Benefits of optical fibers include wide bandwidth and low noise operation. In a telecommunications system that uses optical fibers, there are typically many locations where fiber optic cables containing the optical fibers connect to equipment or other fiber optic cables. To provide these connections, fiber optic connectors are often provided at an end of the fiber optic cable to enable connection and disconnection of the fiber optic cables to a fiber optic adapter. The adapter allows fiber optic cables to be attached to other fiber optic cables singly or to a large network. 
     One negative consequence of using connectors at the ends of fiber optic cables occurs during installation of the fiber optic cables, particularly during connection of a fiber optic cable to a fiber optic adapter. This is generally shown in  FIGS.  1 - 3   . With reference now to  FIG.  1   , a typical optical connection in a fiber optic network between a pair of fiber optic cables  10 ,  12  is shown. The cables  10 ,  12  may be optically coupled together via fiber optic connectors  14 ,  16  that terminate their respective fiber optic cable  10 ,  12 . The connectors  14 ,  16  each cooperate with a fiber optic adapter  18  which retains the connectors  14 ,  16  in a fixed relative orientation. Once assembled in the fiber optic adapter  18 , an optical connection between the ends of the fiber optic cables  10 ,  12  is achieved. Although the connectors  14 ,  16  are shown to be identical and in the form of SC-type connectors (e.g., according to IEC 61754-20: 2012), the depicted features may be applicable to different connector designs, such as MU-type connectors, Ultra Physical Contact (UPC) connectors, Angled Physical Connect (APC) connectors. 
     During installation and with reference to  FIG.  1   , an installer inserts each connector  14  and  16  into the fiber optic adapter  18  as indicated by arrows  52 . Following insertion, a proper, complete coupling of the connector  14  to the fiber optic adapter  18  is shown in  FIG.  2   . A complete coupling of the connector  14  to the fiber optic adapter  18  occurs when the connector  14  is fully seated within adapter  18 . Once at that relative position, the connector  14  and the fiber optic adapter  18  are essentially locked together and may not be inadvertently separated. Optical transmission between the fiber optic cable  10  and the fiber optic cable  12  can occur. The connector  14  and the fiber optic adapter  18  may be separated or unlocked by intentional decoupling. 
     To that end, as shown in  FIG.  2   , the connector  14  includes a plug frame  20  with a shell  22  generally encasing the plug frame  20  and providing surfaces by which an installer (typically a technician) may grip the connector  14  during installation. Stops  24  extend outwardly from the plug frame  20  to engage the fiber optic adapter  18  during installation. The shell  22  is movable relative to the plug frame  20  and cooperates with the fiber optic adapter  18  during installation and during removal of the connector  14  from the adapter  18 . A ferrule  26  (shown in  FIGS.  1 - 3   ) is coupled to the fiber optic cable  10  and extends from the connector  14 . 
     With continued reference to  FIG.  2   , the fiber optic adapter  18  includes a housing  30  (shown in phantom) which receives each of the connectors  14  and  16  from opposing directions as shown in  FIG.  1   . The housing  30  includes a sleeve holder  32  and an engagement portion  34  on each of the opposing sides of a central portion  36  that extends between the sleeve holder  32  and the engagement portion  34  and may extend outwardly relative to the surrounding housing  30  and provide a flange for mounting the fiber optic adapter  18  to another structure. The housing  30  defines at least one cavity on each side of the central portion  36  that cooperates with one of the connectors  14 ,  16 . For example, a cavity  40  is defined between the sleeve holder  32  and the engagement portion  34 . The sleeve holder  32  defines a receptacle  44  (shown in  FIG.  3   ) that receives a split sleeve  46 . The engagement portion  34  includes one or more wedge-shaped tabs  50  that project into the cavity  40  and that are configured to cooperate with the stops  24  on the plug frame  20  during insertion and resisting removal. The central portion  36  may be generally perpendicular to the insertion direction  52  and provide a limit to movement of the connectors  14  and  16  into the cavity  40  in the insertion direction  52 . 
     During installation, and with reference to  FIG.  3   , the installer inserts the plug frame  20  of the connector  14  in one cavity  40  in the direction of arrow  52 . The plug frame  20  slides into the cavity  40  and generally surrounds the sleeve holder  32 . During insertion, the tabs  50  cooperate with the shell  22  and the plug frame  20  and are deflected in a direction outward relative to the plug frame  20  as they contact the stops  24 , as shown. At the same time, the ferrule  26  is received in the receptacle  44  and engages the split sleeve  46 . 
     When installation is complete (as is shown in  FIG.  2   ), with the plug frame  20  fully seated in the cavity  40 , the stops  24  are between the tabs  50  and the central portion  36 . In this position, the connector  14  is locked in the fiber optic adapter  18 . Movement of the plug frame  20  away from the fiber optic adapter  18  in the direction of arrow  54  in  FIG.  2    causes the tab  50  to contact the stop  24 . As shown in  FIG.  2   , this contact and the relative orientation of the surfaces of the tab  50  and stop  24  interferes with further movement in the direction of arrow  54 . Once the tab  50  engages the stop  24 , inadvertent movement of the plug frame  20  relative to the fiber optic adapter  18  in the direction of arrow  54  is prevented. This interference fit between the fiber optic adapter  18  and the connector  14  prevents unintentional removal of the connector  14  from the adapter  18 . Although not shown in  FIG.  2   , a similar structural relationship may exist between the fiber optic adapter  18  and the connector  16  (shown in  FIG.  1   ). When both connectors  14 ,  16  are fully seated into the fiber optic adapter  18 , optical transmission is possible between the fiber optic cable  10  and the fiber optic cable  12  ( FIG.  1   ) and unintentional separation of the connectors  14 ,  16  from the adapter  18  is prevented. 
     However, during installation, the installer sometimes fails to fully insert one or both connectors  14 ,  16  into a locked position in the fiber optic adapter  18 . This is shown by way of example in  FIG.  3   . During installation, the ferrule  26  frictionally engages the split sleeve  46  and resists the installer&#39;s efforts to fully seat the connector  14  into the cavity  40 . Due to this resistance, the installer may mistakenly believe that the connector  14  is fully inserted into the fiber optic adapter  18  and is in the locked position. 
     An example of a failure to fully insert the connector  14  into engagement with the fiber optic adapter  18  is shown in  FIG.  3   . In the position shown, the tabs  50  may contact the stops  24 . In the exemplary position, the engagement portions  34  are deflected outward with the tabs  50  on the stops  24 . Yet, the plug frame  20  is not in an installed position relative to the fiber optic adapter  18 . Despite the incomplete installation, optical transmission through the fiber optic cables  10 ,  12  may occur. In that regard, the ferrule  26  may extend far enough into the split sleeve  46  so that optical transmission between the fiber optic cable  10  and the fiber optic cable  12  ( FIG.  1   ) is possible. Thus, a signal check of the optical transmission quality between cables  10 ,  12  may not indicate the faulty installation. And, a visual inspection of the fiber optic adapter  18  would not reveal the slight outward deflection of the engagement portion  34  relative to the shell  22  since this portion of the fiber optic adapter  18  is hidden from view by the housing  30 . While some connectors have a depth line to indicate full insertion into an adapter, the line on the connector can be difficult to discern and installers sometimes don&#39;t understand the purpose of the line or forget to visually check its location relative to the adapter upon completion of the installation. Thus, the incomplete assembly of the connector  14  and the fiber optic adapter  18  is not easily identified. 
     Despite the incomplete installation, optical transmission service through cables  10  and  12  may commence. Over time, however, the lack of a complete insertion and locking of the connector  14  in the fiber optic adapter  18  permits the connector  14  to separate from the adapter  18 . For example, the connector  14  may gradually back out of the fiber optic adapter  18 , causing the ferrule  26  to move away from a ferrule (not shown) of the corresponding fiber optic cable  12 . The increase in the gap between ferrules degrades optical signal transmission quality between the fiber optic cables  10 ,  12 . Ultimately, degradation may continue to a point of service interruption. When degradation reaches a certain level or when service is interrupted, a service call is required to have a technician identify and correct the cause for the loss in transmission. Identification of the exact problem may be difficult given the above. Thus, current fiber optic adapters suffer from possible incomplete installation and subsequent service interruption which costs time and money to identify and correct. 
     Thus, there is a need in the fiber optic industry for improved fiber optic adapters and methods for coupling fiber optic cables in fiber optic networks. More particularly, there is a need for fiber optic adapters and methods that reduce or eliminate incomplete coupling in fiber optic network connections. 
     SUMMARY 
     A fiber optic adapter for use with a fiber optic connector having a plug frame with a stop and a shell is provided. The fiber optic adapter indicates during installation of the connector when the connector is not properly installed in the fiber optic adapter. The fiber optic adapter includes a housing that has a cavity at one end for receiving the fiber optic connector. The housing contains a sliding latch that is configured to contact the fiber optic connector when the fiber optic connector is inserted into the cavity. The sliding latch is movable within the housing from an extended position to a latched position. There is also a connector latch in the housing that is configured to engage the stop when the sliding latch is at the latched position. One or more springs are operably coupled to the sliding latch. At least one spring of the one or more springs is compressible during insertion of the fiber optic connector into the cavity. When the fiber optic connector is inserted into the cavity, the fiber optic adapter indicates when the sliding latch is not at the latched position. In an exemplary embodiment, the at least one compressible spring is capable of producing a total force that is sufficient to move the fiber optic connector in a direction out of the cavity when the sliding latch is not at the latched position. In an exemplary embodiment, the at least one spring is capable of moving the fiber optic connector in a direction out of the cavity when the sliding latch is moved by a distance less than a distance between the extended position and the latched position. 
     The housing may include a divider that defines a passageway adjacent the cavity and the sliding latch may include a housing engagement arm that is movable in the passageway. The divider may include a through-slot opening to the cavity and to the passageway, and the connector latch may include a protrusion positioned to extend through the through-slot when the fiber optic connector is inserted into the cavity. In this embodiment, the protrusion is configured to contact the housing engagement arm through the through-slot when the sliding latch moves toward the latched position. The protrusion deflects the housing engagement arm away from the divider as the sliding latch moves toward the latched position. The housing engagement arm may include a stop, and the divider may define a ledge that is engageable with the stop at the latched position. The sliding latch may form an interference fit with the housing at the latched position. The at least one compressible spring may be compressed when the sliding latch is at the latched position. The passageway may open at the end of the housing adjacent the cavity, and the housing engagement arm may be visible in the passageway when the sliding latch is at the extended position. 
     In an exemplary embodiment, the one or more springs includes at least one spring that is coupled to the sliding latch and is extendable when the fiber optic connector is inserted into the cavity. The at least one extendable spring is coupled to an indicator flag that projects from the housing when the sliding latch is not at the latched position. In one embodiment, the indicator flag has only two positions when the connector is inserted into the cavity, an extended position in which the visual indicator projects from the housing and a retracted position in which the visual indicator is within the housing. 
     In an exemplary embodiment, a fiber optic adapter for use with a fiber optic connector having a plug frame with a stop and a shell is provided. The fiber optic adapter includes a housing that has a cavity at one end for receiving the fiber optic connector. The housing contains a sliding latch that is movable in the housing and is configured to contact the fiber optic connector when the fiber optic connector is inserted into the cavity. The sliding latch includes a housing engagement arm and has an extended position and a latched position at which the fiber optic connector is coupled to the fiber optic adapter. A connector latch may be configured to engage the stop when the sliding latch is at the latched position. The connector latch has a protrusion that deflects the housing engagement arm outwardly as the sliding latch is moved toward the latched position. At least one spring is operably coupled to the sliding latch. The at least one spring is compressible during insertion of the fiber optic connector into the cavity and is capable of moving the fiber optic connector in a direction out of the cavity when the sliding latch is moved by a distance less than a distance between the extended position and the latched position. The housing engagement arm may form an interference fit with the housing at the latched position. In one embodiment, the housing includes a divider defining a passageway, and the housing engagement arm is movable in the passageway. The divider may include a through-slot, and the protrusion may extend through the through-slot when the sliding latch is moved toward the latched position. The divider may include a ledge in the passageway, and the housing engagement arm may contact the ledge at the latched position. In one embodiment, the at least one spring is compressed when the sliding latch is in the latched position. 
     In an exemplary embodiment, a fiber optic adapter for use with a fiber optic connector having a plug frame with a stop and a shell is provided. The fiber optic adapter includes a housing that has a cavity at one end for receiving the fiber optic connector. The adapter includes a sliding latch that is configured to contact the fiber optic connector when the fiber optic connector is inserted into the cavity. The sliding latch is movable within the housing from an extended position to a latched position. A connector latch is configured to engage the stop when the sliding latch is at the latched position. One or more springs are operably coupled to the sliding latch. At least one spring of the one or more springs is compressible during insertion of the fiber optic connector into the cavity. An indicator flag movable in the housing has an extended position and a retracted position. There is at least one spring coupled to the sliding latch and the indicator flag. The at least one spring is extendable when the fiber optic connector is inserted into the cavity. When the sliding latch reaches the latched position, the indicator flag is moved from the extended position to the retracted position. The indicator flag may have only the extended position and the retracted position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description explain principles and operation of the various embodiments. Features and attributes associated with any of the embodiments shown or described may be applied to other embodiments shown, described, or appreciated based on this disclosure. 
         FIG.  1    is a perspective disassembled view of an end-to-end connection between two fiber optic connectors with a conventional fiber optic adapter; 
         FIG.  2    is a cross-sectional view of a connector coupled to a conventional fiber optic adapter; 
         FIG.  3    is a cross-sectional view of a conventional fiber optic adapter and a connector partially inserted into the adapter; 
         FIG.  4    is a perspective view of a fiber optic adapter according to one embodiment of the disclosure; 
         FIG.  5    is a partial cross-sectional perspective view of the embodiment of the fiber optic adapter shown in  FIG.  4   ; 
         FIG.  6    is a disassembled perspective view of the fiber optic adapter shown in  FIG.  4   ; 
         FIGS.  7 - 9    are schematic sectional views of the fiber optic adapter of  FIG.  4    illustrating a sequence of inserting a connector into the fiber optic adapter during installation; 
         FIG.  10    is a schematic sectional view of the fiber optic adapter of  FIG.  4    with a connector in an installed position; 
         FIG.  11    is a schematic sectional view of the fiber optic adapter of  FIG.  4    illustrating disassembly of a connector from the fiber optic adapter following installation; 
         FIG.  12    is a perspective view of a fiber optic adapter according to another embodiment of the disclosure; 
         FIG.  13    is a partial cross-sectional perspective view of the embodiment of the fiber optic adapter shown in  FIG.  12   ; 
         FIG.  14    is a disassembled perspective view of the fiber optic adapter shown in  FIG.  12   ; 
         FIGS.  15 - 17    are schematic sectional views of the fiber optic adapter of  FIG.  12    illustrating a sequence of inserting a connector into the fiber optic adapter during installation; 
         FIG.  18    is a schematic sectional view of the fiber optic adapter of  FIG.  12    with a connector in an installed position; 
         FIG.  19    is a cross-sectional view of the adapter of  FIG.  12    illustrating disassembly of the connector from the fiber optic adapter following installation; 
         FIG.  20    is a perspective view of a fiber optic adapter according to another embodiment of the disclosure; 
         FIG.  21    is a partial cross-sectional perspective view of the embodiment of the fiber optic adapter shown in  FIG.  20   ; 
         FIG.  22    is a disassembled perspective view of the fiber optic adapter shown in  FIG.  20   ; 
         FIGS.  23 - 25    are schematic sectional views of the fiber optic adapter of  FIG.  20    illustrating a sequence of inserting a connector into the fiber optic adapter during installation; 
         FIG.  26    is a schematic sectional view of the fiber optic adapter of  FIG.  20    with a connector in an installed position; and 
         FIGS.  27 - 29    are schematic sectional views of the fiber optic adapter of  FIG.  20    illustrating disassembly of a connector from the fiber optic adapter following installation. 
     
    
    
     DETAILED DESCRIPTION 
     With reference generally to the figures, a fiber optic adapter according to embodiments of the disclosure provides an indication when a connector, such as the connectors  14 ,  16  of  FIG.  1   , is incompletely (i.e., improperly) installed in the fiber optic adapter. The indication provided generally occurs immediately upon insertion or once the connector is inserted into the fiber optic adapter and released. That is, the fiber optic adapter spontaneously acts in the presence of the installer. An improperly installed connector is apparent to the installer during installation. Thus, by an action of the fiber optic adapter in response to an incomplete insertion of a connector, a subsequent service call due to improper installation of the connector is avoided. 
     With reference to an exemplary embodiment shown in  FIGS.  4 - 11   , a fiber optic adapter  100  may forcibly move a connector  14  (shown in  FIGS.  1  and  7 - 11   ) from the adapter  100  if the connector  14  is improperly installed during installation. This is described with reference to  FIGS.  7 - 9   . In this exemplary embodiment, if the installer fails to insert the connector  14  far enough into the fiber optic adapter  100 , once the installer releases the connector  14 , the adapter  100  will spontaneously push the connector  14  backwards and in a direction out of the adapter  100 . In essence, in one embodiment, if the installer fails to properly insert the connector  14 , it pops back out. Stated another way, the fiber optic adapter  100  automatically uninstalls an incompletely inserted connector. This forcible movement of the connector  14  may be accompanied by an audible response, such as a click or snap, and so may further attract the installer&#39;s attention to an incomplete installation. Advantageously, if the forcible movement results in ejection of an improperly installed connector  14 , this provides a visual (and likely audible) indication to the installer that the connector  14  was not properly seated. In that situation, the installer may reattempt to insert the connector  14  into the fiber optic adapter  100  with sufficient force to ensure that the connector  14  is inserted far enough to lock the connector  14  in the adapter  100 . 
     Alternatively, if the connector is not fully ejected from the fiber optic adapter  100 , forcible movement of the connector opposite the direction of installation may result in sufficient movement of the connector  14  to increase a gap between the fiber optic connections (e.g., between two ferrules terminating ends of fiber optic cables, such as the cables  10  and  12  shown in  FIG.  1   ). The gap produced may be sufficient to interrupt signal transmission. While the connector may not be ejected, the connector will fail a transmission signal check following installation. Thus, the improper installation is timely identified. 
     Once the connector  14  is properly seated in the fiber optic adapter  100 , optical transmission through the connection and sustained service is assured. While a simplex connector is shown and described, embodiments of the invention are not limited to use with simplex connectors. For example, it is contemplated that fiber optic adapters according to embodiments may be used with duplex and quad connectors. Further, while SC connectors are shown, embodiments are not limited to SC connectors, as MU connectors are contemplated. 
     With reference to  FIGS.  4  and  5   , in one embodiment, the fiber optic adapter  100  includes a housing  102  having two portions  104 ,  106  which are joined together, for example, at a joint  110  (a snap fit construction is shown). The housing  102  is generally rectangular in shape with sides  112 ,  114 ,  116 , and  118  and opposing ends  120  and  122 . The ends  120  and  122  define cavities  124  and  126 , respectively, for receiving a respective one of connectors  14 ,  16  (shown in  FIG.  1   ). One of the sides, such as side  112 , includes alignment slots  130 ,  132  that open to a respective cavity  124 ,  126  and receive a portion of the connector  14 ,  16 . The slots  130 ,  132  ensure that the connector  14 ,  16  is inserted in a predetermined orientation. 
     One end, such as end  120 , includes one or more dividers  134  that defines passageways  138  adjacent the cavity  124 . In the exemplary embodiment shown, there is a pair of passageways  138  that are spaced apart by the cavity  124 . Sides  116 ,  118  of the housing portion  106  may include silos  136  that generally project from the sides  116 ,  118  of the housing portion  106 . The fiber optic adapter  100  includes opposing cavities  124  and  126  which receive connectors  14 ,  16  and may be a female-to-female type adapter to receive a connector  14 ,  16  at each end  120  and  122 . Although not shown, the end  122  may be provided with a male connector. With the male connector at end  122  and the cavity  124  at the opposing end  120 , the fiber optic adapter  100  may be a male-to-female type adapter. 
     With reference now to  FIGS.  5  and  6   , in the exemplary embodiment shown, the housing  102  contains one or more springs  140  that in cooperation with a sliding latch  142  provide a force sufficient to move a connector outwardly from within the cavity  124  if the connector is not fully inserted to a locked position in the fiber optic adapter  100 . In the embodiment shown, two springs  140  are engaged with the sliding latch  142  and are spaced apart at the sides  116 ,  118  of the housing  102 . Embodiments of the invention are not limited to two springs  140 . That is, it is within the scope of the present disclosure that alternate number of springs  140  may be used. The spring force may be sufficient to eject a connector from the cavity  124  or at a minimum be sufficient to move a connector in an outward direction from the cavity  124  by a distance sufficient to degrade or prevent optical transmission in fiber optic cable  10 . In either condition, an installer may either visually identify the improper installation or identify the poor optical transmission during a transmission quality check following installation. 
     In addition to the springs  140  and sliding latch  142 , the housing  102  contains a connector latch  144  abutting a sleeve holder  146 . The connector latch  144  may be coupled to the sleeve holder  146 . The connector latch  144  and sleeve holder  146  collectively house a sleeve  150  in receptable  174 . The connector latch  144  and the sleeve holder  146  are configured to couple connectors (e.g., connectors  14  and  16  of  FIG.  1   ) within cavities  124  and  126 , respectively. By way of example,  FIGS.  7 - 9    illustrate a connector  14  inserted into cavity  124 , as described below. 
     In one embodiment, the silos  136  of the housing portion  106  define cavities  152  that receive the springs  140  and provide a surface against which the springs  140  may be compressed during insertion of a connector. The sliding latch  142  includes nipples  154  in silos  136  and that receive an opposing end of springs  140 . The springs  140  are therefore compressible between the sliding latch  142  and the housing portion  106  during use of the fiber optic adapter  100  with the cavities  152  and nipples  154  defining a compression axis  164  for each spring  140 . This is shown in  FIG.  5   , which depicts the fiber optic adapter  100  with springs  140  in a position to be compressed. The sliding latch  142  and springs  140  are movable in the housing  102  relative to the connector latch  144 , as is schematically shown in  FIGS.  7 - 9   , described below. 
     The sliding latch  142  further includes a pair of housing engagement arms  156  that extend in an opposite direction from the nipples  154  and cooperate with the housing portion  104  when a connector is fully inserted into the cavity  124 . A pair of cross beams  160  extend between the engagement arms  156  so that the beams  160  and arms  156  collectively with define a rectangular opening in the sliding latch  142 . The rectangular opening receives the connector latch  144 . A connector inserted into cavity  124  may contact the cross beams  160 . Each of the housing engagement arms  156  includes a stop  162  (shown in  FIGS.  7 - 10   ) extending inwardly to engage the housing portion  104  at ledges  158  (shown in  FIG.  5   ) during insertion of a connector. In the exemplary embodiment, the ledges  158  are formed on the dividers  134  in the passageway  138 . The dividers  134  also include a through-slot  168  that receives a portion of the connector latch  144 . The through-slot  168  may be proximate each ledge  158  and provide an opening between the cavity  124  and the passageway  138 . As shown in  FIG.  5   , tips of the arms  156  may be observable through passageways  138  on the end  120  of the fiber optic adapter  100 . In embodiments where the passageways  138  do not open at the end  120 , the arms  156  are not visible from end  120 . 
     With continued reference to  FIGS.  5  and  6   , in the exemplary embodiment, the connector latch  144  is contained in the housing portion  104  proximate the cavity  124  and is configured to latch a connector in the cavity  124  to the housing  102 . In that regard, the connector latch  144  includes a pair of engagement arms  170  having wedge-shaped tabs  172 . Wedge-shaped tabs  172  face inwardly in the cavity  124  to engage a connector inserted into cavity  124 . The engagement arms  170  also include a protrusion  176  extending outwardly from each arm  156  opposite the wedge-shaped tabs  172 . As shown in  FIG.  5   , the protrusions  176  are positioned in the through-slot  168  in the dividers  134 . While shown in the through-slot  168 , the protrusions  176  may be proximate the through-slot  168 . In either orientation (i.e., positioned in or proximate), the protrusions  176  are movable through the through-slot  168  to engage the housing engagement arms  156  of the sliding latch  142  during insertion of a connector into cavity  124 , as is described below. In addition, an ear  178  extends laterally outward (e.g., toward the sides  112  and  114  of the housing portion  104  or perpendicularly to the protrusion  176 ) from the arm  170  between the protrusion  176  and the tabs  172  and is configured to contact a shell of a connector. 
     As mentioned previously, the sleeve holder  146  is received in the housing portion  106  and abuts the connector latch  144 . The sleeve holder  146  is configured to couple a connector that is inserted into the cavity  126 . In that regard, the sleeve holder  146  includes engagement arms  180  having wedge-shaped stops  182  much like engagement arms  170  and wedge-shaped tabs  172  of the connector latch  144 . The sleeve holder  146  and the connector latch  144  define the receptacle  174  that receive the sleeve  150 . 
     With reference to  FIGS.  7 - 9   , insertion of a connector  14  into the fiber optic adapter  100  is shown. In  FIG.  7   , an installer inserts the connector  14  according to arrow  186  into the cavity  124  on the end  120  of the fiber optic adapter  100 . This may occur before or after insertion of a connector into the cavity  126 . In the cavity  124 , the connector  14  contacts the connector latch  144  at the engagement arms  170 . Although not shown, initial contact of the shell  22  is at the ears  178 . This contact begins separation of the engagement arms  170 . With the connector  14  in this position, the springs  140  are at their maximum extension with the sliding latch  142  is at its fully extended, unlatched position with arms  156  at the end  120  of the housing  104 . Although not shown, while the springs  140  are at their maximum extension, the springs  140  may be initially compressed though that compression may be minimal. The housing engagement arms  156  may be visible in the passageways  138  when the sliding latch  142  is in its fully extended, unlatched position. 
     With reference to  FIG.  8   , when the installer pushes the connector  14  further into the cavity  124  (according to arrow  186 ), the engagement arms  170  of the connector latch  144  are deflected outwardly toward the sides  116 ,  118  of the housing  102 . In that regard, the forcible insertion of the connector  14  pushes the shell  22  against the ears  178  thereby pushing the tabs  172  apart. As the wedge-shaped tabs  172  are deflected outwardly toward the sides  116 ,  118 , the protrusions  176  of the engagement arms  170  extend further through the through-slot  168  in the divider  134  and protrude into passageways  138 . In the position shown in  FIG.  8   , the connector  14  may initially contact the cross beams  160  of the sliding latch  142  though the springs  140  may not be appreciably compressed by that contact. 
     Because the ferrule  26  may protrude slightly beyond the plug frame  20 , the ferrule  26  may extend slightly into a recess formed by the sleeve  150 . 
     With reference to  FIG.  9   , further forcible insertion of the connector  14  into the cavity  124  pushes on the sliding latch  142  and compresses the springs  140 . As the installer pushes the connector  14  further into the cavity  124 , the plug frame  20  and/or shell  22  contacts the cross beam  160  of the sliding latch  142 . Movement of the sliding latch  142  according to arrow  186  compresses the springs  140  along axis  164  and brings the housing engagement arms  156  into contact with the protrusions  176 . The protrusions  176  may deflect the housing engagement arms  156  outwardly and away from contact with the divider  134 . In the exemplary embodiment, at the same time as the housing engagement arms  156  contact the protrusions  176 , the wedge-shaped tabs  172  of the connector latch  144  contact and begin to ride over the stops  24  of the plug frame  20 . 
     At the position shown in  FIG.  9   , while the connector  14  is inserted into the fiber optic adapter  100 , the connector  14  is not yet locked or latched to the fiber optic adapter  100 . If the technician releases the connector  14  at this location, the springs  140  will push the connector  14  via the sliding latch  142  in the direction of arrow  190  (i.e., opposite of the insertion direction  186 ). The compressed springs  140  apply a force in a direction opposite to that of insertion. Thus, in the absence of the installer holding onto the connector  14 , the compressed springs  140  will spontaneously push the connector  14  in the direction opposite to that of insertion. As set forth above, a force of the springs  140  produced by displacement x (labeled in  FIG.  9   ) from the initial position of the sliding latch  142  to the position of the sliding latch  142  just before a latched/locked position is achieved (shown in  FIG.  10   ) may be sufficient to push the connector  14  from the cavity  124 . By way of example, a spring constant according to Hooke&#39;s law of one spring  140  according to embodiments of the invention may range from 0.5 N/mm to 1.8 N/mm. 
     If the springs  140  eject the connector  14  from the fiber optic adapter  100 , this provides a visual indication (and likely an audible indication) that the connector  14  was not fully inserted and latched in the fiber optic adapter  100 . Alternatively, movement of the connector  14  in the direction of arrow  192  is sufficient to cause optical transmission failure to/from the optical fiber  10 . Thus, failure to fully insert the connector  14  to a latched/locked position results in an optical transmission signal failure that should be identified when the installer performs a signal quality check. As such, the incompletely inserted connector  14  is identified during installation and reduces or eliminates the need to dispatch a technician at a later time to investigate transmission degradation/failure due to incompletely installed connectors as is described above in  FIGS.  1 - 3   . 
     With further insertion of the connector  14  into the fiber optic adapter  100  from the position shown in  FIG.  9    to the position shown in  FIG.  10   , a latched position is reached. In the latched position, the connector  14  is locked to the fiber optic adapter  100 . That is, the connector  14  and the adapter  100  resist their inadvertent separation. To that end, with further movement of the sliding latch  142  in the direction of arrow  186  ( FIG.  9   ), the stops  24  of the plug frame  20  move past the wedge-shaped tabs  172 . This permits the engagement arms  170  to spring back toward their undeflected positions. The wedge-shaped tabs  172  move to a position in which they form an interference fit to limit movement of the stop  24  on the plug frame  20  in a direction indicated by arrow  192 . The stops  24  are then positioned between the wedge-shaped tabs  172  and the sleeve holder  146  and are effectively trapped in the fiber optic adapter  100 . Thus, the connector  14  is latched to the fiber optic adapter  100  at this position. This configuration resists inadvertent, unintentional removal of the connector  14  from the fiber optic adapter  100 . 
     Also, in the latched position, a substantial portion or all the force of the compressed springs  140  is carried by the housing  102  and is not transferred onto the connector latch  144  or connector  14 . In the exemplary embodiment, once the engagement arms  170  are released and move toward their original, undeflected positions, the corresponding protrusions  176  disengage from contact with the housing engagement arms  156 , and the housing engagement arms  156  move toward their original, undeflected positions (or inwardly toward the connector  14 ) to engage with the dividers  134 . The stops  162  on the housing engagement arms  156  engage the ledges  158  on the divider  134  to form an interference fit. This interference fit resists movement of the sliding latch  142  from force applied by the compressed springs  140  in the direction of arrow  192 . Once contact is made between the sliding latch  142  and the housing  102 , the force from the compressed springs  140  is predominately carried by the housing  102  via the ledges  158  on the dividers  134  and not by the stops  24  and wedge-shaped tabs  172 . Advantageously, the force from the compressed springs  140  is not carried appreciably by the connector  14  and the connector latch  144 . This arrangement is believed to prolong the life of the connector  14  and/or prevent physical damage to the connector  14  over time. 
     With reference to  FIG.  11   , while the fiber optic adapter  100  resists unintentional, inadvertent removal of the connector  14  when it is in the latched position (shown in  FIG.  10   ), a technician can remove the connector  14  from the fiber optic adapter  100 . Removal includes moving the wedge-shaped tabs  172  of the connector latch  144  from their interference position with the stops  24  on the plug frame  20  and withdrawing the connector  14  from the fiber optic adapter  100 . To move the wedge-shaped tabs  172  out of an interference position with the stops  24 , the technician slides the shell  22  relative to the plug frame  20  in the direction of arrow  194 . The shell  22  engages the ears  178  thereby pushing the wedge-shaped tabs  172  outwardly relative to the stops  24 , as shown. This outward motion of the wedge-shaped tabs  172  also moves the protrusions  176  outwardly to engage the housing engagement arms  156  through the through-slot  168 . This movement disengages the housing engagement arms  156  from the ledges  158  (shown in  FIG.  10   ). Once the wedge-shaped tabs  172  clear the stops  24  and the sliding latch  142  is freed from ledge  158 , the connector  14  is movable in the direction of arrow  194  and so is removable from the fiber optic adapter  100 . Further, once the sliding latch  142  is freed from the ledge  158 , the compressed springs  140  apply force in the direction of arrow  194  and may aid the technician in removal of the connector  14  from the adapter  100 . 
     With reference to an exemplary embodiment shown in  FIGS.  12 - 19   , a fiber optic adapter  200  may forcibly move a connector  14  (shown in  FIGS.  1  and  15 - 19   ) from the adapter  200  if the connector  14  is improperly installed during installation. The fiber optic adapter  200  functions much like the fiber optic adapter  100  shown in  FIGS.  4 - 11   . The interaction of the fiber optic adapter  200  with the connector  14  is described with reference to  FIGS.  15 - 17   . In this exemplary embodiment, if the installer fails to insert the connector  14  far enough into the fiber optic adapter  200 , once the installer releases the connector  14 , the adapter  200  will spontaneously push the connector  14  backwards and in a direction out of the adapter  200 . In essence, in one embodiment, if the installer fails to properly insert the connector  14 , it pops back out. Stated another way, the fiber optic adapter  200  automatically uninstalls an incompletely inserted connector. This forcible movement of the connector  14  may be accompanied by an audible response, such as a click or snap, and so may further attract the installer&#39;s attention to an incomplete installation. Advantageously, if the forcible movement results in ejection of an improperly installed connector  14 , this provides a visual indication to the installer that the connector  14  was not properly seated. In that situation, the installer may reattempt to insert the connector  14  into the fiber optic adapter  200  with sufficient force to ensure that the connector  14  is inserted far enough to lock the connector  14  in the adapter  200 . 
     Alternatively, if the connector  14  is not fully ejected from the fiber optic adapter  200 , the forcible movement of the connector  14  in a direction opposite the direction of installation may result in sufficient movement of the connector  14  to increase a gap between the fiber optic connections (e.g., between two ferrules (not shown) terminating ends of fiber optic cables, such as the cables  10  and  12  shown in  FIG.  1   ). The gap produced may be sufficient to interrupt signal transmission, and as such, the connector  14  will fail a transmission signal check following installation thereby alerting the installer of the improper connection. 
     Once the connector  14  is properly seated in the fiber optic adapter  200 , optical transmission through the connection and sustained service is assured. While a simplex connector is shown and described, embodiments of the invention are not limited to use with simplex connectors. For example, it is contemplated that fiber optic adapters according to embodiments may be used with duplex and quad connectors. Further, while SC connectors are shown, embodiments are not limited to SC connectors, as MU connectors are contemplated. 
     With reference to  FIGS.  12 ,  13 , and  14   , in one embodiment, the fiber optic adapter  200  includes a housing  202  having two portions  204 ,  206  which are joined together, for example, at a joint  210  (a snap fit construction is shown). The housing  202  is generally rectangular in shape and differs from the housing  102  of fiber optic adapter  100  in shape but having sides  212 ,  214 ,  216 , and  218  and opposing ends  220  and  222 . The ends  220  and  222  define cavities  224  and  226 , respectively, for receiving a respective one of connectors  14 ,  16  (shown in  FIG.  1   ). One of the sides, such as side  212 , includes alignment slots  130 ,  132  that open to a respective cavity  224 ,  226  and receive a portion of the connector  14 ,  16 . The slots  130 ,  132  ensure that the connector  14 ,  16  is inserted in a predetermined orientation. 
     One end, such as end  220 , includes one or more dividers  234  that defines passageways  238  adjacent the cavity  224 . In the exemplary embodiment shown, there is a pair of passageways  238  that are spaced apart by the cavity  224 . Sides  216 ,  218  of the housing portion  204  may include silos  236  that generally project from the side  216  of the housing portion  204 . The housing  202  differs from the housing  102  ( FIG.  4   ) in the location of the silos  236  in view of the rearrangement of springs within the housing  202 , described below. Advantageously, this provides a housing  206  that is more similar in shape and size relative to current adapters and thus, the fiber optic adapter  200  may find use in those applications. The fiber optic adapter  200  includes cavities  224  and  226  which receive connectors  14 ,  16  and may be a female-to-female type adapter to receive connectors  14 ,  16  at each end  220  and  222 . Although not shown, the end  222  may be provided with a male connector. With the male connector at end  222  and the cavity  224  at the opposing end  220 , the fiber optic adapter  200  may be a male-to-female type adapter. 
     With reference now to  FIGS.  13  and  14   , in the exemplary embodiment shown, the housing  202  contains one or more springs  240  that in cooperation with a sliding latch  242  provide a force sufficient to move a connector outwardly from within the cavity  224  if the connector is not fully inserted to a locked position in the fiber optic adapter  200 . In the embodiment shown, two springs  240  are engaged with the sliding latch  242  and spaced apart at the sides  216 ,  218  of the housing  202 . Embodiments of the invention are not limited to two springs  240 . That is, it is within the scope of the present disclosure that alternate number of springs  240  may be used. The spring force may be sufficient to eject a connector from the cavity  224  or at a minimum be sufficient to move a connector in an outward direction from the cavity  224  by a distance sufficient to degrade or prevent optical transmission in fiber optic cable  10 . In either condition, an installer may either visually identify the improper installation or identify the poor optical transmission during a transmission quality check following installation. 
     In addition to the springs  240  and sliding latch  242 , the housing  202  contains a connector latch  244  abutting a sleeve holder  246 . The connector latch  244  may be coupled to the sleeve holder  246 . The connector latch  244  and sleeve holder  246  collectively house a sleeve  250  in receptacle  274 . The connector latch  244  and the sleeve holder  246  are configured to couple connectors (e.g., connectors  14  and  16  of  FIG.  1   ) within cavities  224  and  226 , respectively. By way of example,  FIGS.  15 - 17    illustrate a connector  14  inserted into cavity  224 , as described below. 
     In one embodiment, the silos  236  of the housing portion  206  define cavities  252  that receive the springs  240  and provide a surface against which the springs  240  may be compressed during insertion of a connector. The sliding latch  242  includes nipples  254  that receive an opposing end of springs  240 . The springs  240  are therefore compressible between the sliding latch  242  and the housing portion  206  during use of the fiber optic adapter  200  with the cavities  252  and nipples  254  define a compression axis  264  for each spring  240 . This is shown in  FIG.  13   , which depicts the fiber optic adapter  200  with springs  240  in a position to be compressed. The sliding latch  242  and springs  240  are movable in the housing  202  and relative to the connector latch  244 , as is schematically shown in  FIGS.  15 - 17   , described below. 
     The sliding latch  242  further includes a pair of housing engagement arms  256  that cooperate with the housing portion  204  when a connector is fully inserted into the cavity  224 . As shown, the nipples  254  are located toward end  220  so that the springs  240  are largely contained in the housing portion  204 . A pair of cross beams  260  extend between the engagement arms  256  so that the beams  260  and arms  256  collectively with define a rectangular opening in the sliding latch  242 . The rectangular opening receives the connector latch  244 . A connector inserted into cavity  224  may contact the cross beams  260 . Each of the housing engagement arms  256  includes a stop  262  (shown in  FIGS.  15 - 19   ) extending inwardly to engage the housing portion  204  at ledges  258  (shown in  FIG.  18   ) during insertion of a connector. In the exemplary embodiment, the ledges  258  are formed on the dividers  234  in the passageway  238 . The dividers  234  also include a through-slot  268  that receives a portion of the connector latch  244 . The through-slot  268  may be proximate each ledge  258  and provide an opening between the cavity  224  and the passageway  238 . As shown in  FIG.  12   , tips of the arms  256  may be observable through passageways  238  on the end  220  of the fiber optic adapter  200 . In embodiments where the passageways  238  do not open at the end  220 , the arms  256  are not visible from end  220 . 
     With continued reference to  FIGS.  13  and  14   , in the exemplary embodiment, the connector latch  244  is substantially the same as connector latch  144  shown in  FIG.  5    and is contained in the housing portion  204  proximate the cavity  224 . The connector latch  244  is configured to latch a connector in the cavity  224  to the housing  202 . In that regard, the connector latch  244  includes a pair of engagement arms  270  having wedge-shaped tabs  272 . Wedge-shaped tabs  272  face inwardly in the cavity  224  and function much like the tabs  50  of the engagement portion  34  shown in  FIG.  2   . The engagement arms  270  also include a protrusion  276  extending outwardly from each arm  270  opposite the wedge-shaped tabs  272 . As shown in  FIG.  13   , the protrusions  276  are positioned proximate or in the through-slot  268  in the dividers  234  and are movable relative to the through-slot  268  to engage the housing engagement arms  256  of the sliding latch  242  during insertion of a connector into cavity  224 , as is described below. In addition, an ear  278  extends laterally outward (e.g., toward the sides  112  and  114  of the housing portion  104 ) from the arm  270  between the protrusion  276  (and may be generally perpendicular to the protrusions  276 ) and the tabs  272  and is configured to contact a shell of a connector. 
     As mentioned previously, the sleeve holder  246  is received in the housing portion  206  and abuts the connector latch  244 . The sleeve holder  246  is configured to couple a connector that is inserted into the cavity  226 . In that regard, the sleeve holder  246  includes engagement arms  280  having wedge-shaped stops  282  much like engagement arms  270  and wedge-shaped tabs  272  of the connector latch  244 . The wedge-shaped tabs  272  engage stops on the plug frame  20  of the connector. The sleeve holder  246  and the connector latch  244  define the receptacle  274  that receive the sleeve  250 . 
     With reference to  FIGS.  15 - 17   , insertion of a connector  14  into the fiber optic adapter  200  is shown. In  FIG.  15   , an installer inserts the connector  14  according to arrow  286  into the cavity  224  on the end  220  of the fiber optic adapter  200 . This may occur before or after insertion of a connector into the cavity  226  (not shown). In the cavity  224 , the connector  14  contacts the connector latch  244  at the engagement arms  270 . Although not shown, initial contact of the shell  22  is at the ears  278 . With the connector  14  in this position, the springs  240  are extended so that the sliding latch  242  is at its fully extended, unlatched position. Although not shown, the springs  240  may be initially compressed though that compression may be minimal. The housing engagement arms  256  may be visible in the passageways  238  when the sliding latch  242  is in its fully extended position. 
     With reference to  FIG.  16   , when the installer pushes the connector  14  further into the cavity  224  (according to arrow  286 ), the engagement arms  270  of the connector latch  244  are deflected outwardly toward the sides  216 ,  218 . In that regard, the forcible insertion of the connector  14  pushes the shell  22  against the ears  278  thereby pushing the tabs  272  apart. As the wedge-shaped tabs  272  are deflected outwardly toward the sides  216 ,  218 , the protrusions  276  of the engagement arms  270  extend further through the through-slot  268  in the divider  234  and protrude into passageways  238 . In the position shown in  FIG.  16   , the connector  14  may initially contact the cross beams  260  of the sliding latch  242  though the springs  140  may not be appreciably compressed by that contact. Because the ferrule  26  may protrude slightly beyond the plug frame  20 , the ferrule  26  may extend slightly into a recess formed by the sleeve  250 . 
     With reference to  FIG.  17   , further forcible insertion of the connector  14  into the cavity  224  pushes on the sliding latch  242  and compresses the springs  240 . As the installer pushes the connector  14  further into the cavity  224 , the plug frame  20  and/or shell  22  contacts the cross beam  260  of the sliding latch  242 . Movement of the sliding latch  242  according to arrow  190  compresses the springs  240  and brings the protrusions  176  into contact with the housing engagement arms  256  as the protrusions  276  are deflected outward by contact between the ears  278  and the shell  22  of the plug frame  20 . 
     At the position shown in  FIG.  17   , while the connector  14  is inserted into the fiber optic adapter  200 , the connector  14  is not yet locked or latched to the fiber optic adapter  200 . If the technician releases the connector  14  at this location, the springs  240  will push the connector  14  via the sliding latch  242  in the direction of arrow  294 . The compressed springs  140  apply a force in a direction opposite to that of insertion. Thus, in the absence of the installer holding onto the connector  14 , the compressed springs  240  will spontaneously act in a direction opposite to that of insertion. As set forth above, a force of the springs  240  produced by displacement y (labeled in  FIG.  17   ) from the initial position of the sliding latch  242  to the position of the sliding latch  242  just before a latched/locked position is achieved (shown in  FIG.  18   ) may be sufficient to push the connector  14  from the cavity  224 . By way of example, a spring constant according to Hooke&#39;s law of one spring  240  according to embodiments of the invention may range from 0.7 N/mm to 2.4 N/mm. 
     If the springs  240  eject the connector  14  from the fiber optic adapter  100 , this provides a visual indication that the connector  14  was not fully inserted and latched in the fiber optic adapter  200 . Alternatively, movement of the connector  14  in the direction of arrow  294  ( FIG.  17   ) is sufficient to cause optical transmission failure to/from the optical fiber  10  due to larger spacing between the optical fibers. Thus, failure to fully insert the connector  14  to a latched/locked position results in an optical transmission signal failure that should be identified when the installer performs a signal quality check. As such, the incompletely inserted connector  14  is identified during installation and reduces or eliminates the need to dispatch a technician at a later time to investigate transmission degradation/failure due to incompletely installed connectors as is described above in  FIGS.  1 - 3   . 
     With further insertion of the connector  14  into the fiber optic adapter  100  from the position shown in  FIG.  17    to the position shown in  FIG.  18   , a latched/locked position is reached. In this position, the connector  14  is locked to the fiber optic adapter  200 . That is, the connector  14  and the adapter  200  resist their inadvertent separation. To that end, with further movement of the sliding latch  242  in the direction of arrow  286  ( FIG.  17   ), the stops  24  of the plug frame  20  move past the wedge-shaped tabs  272 . This permits the engagement arms  270  to spring back toward their undeflected positions. The wedge-shaped tabs  272  move to a position in which they form an interference fit to limit movement of the stop  24  on the plug frame  20  in a direction indicated by arrow  294 . The stops  24  are then positioned between the wedge-shaped tabs  272  and the sleeve holder  246  and are effectively trapped in the fiber optic adapter  200 . Thus, the connector  14  is latched to the fiber optic adapter  200  at this position. This configuration resists inadvertent, unintentional removal of the connector  14  from the fiber optic adapter  200 . 
     In the exemplary embodiment, once the engagement arms  270  are released and move toward their original, undeflected positions, the corresponding protrusions  276  disengage from contact with the housing engagement arms  256 . The housing engagement arms  256  therefore also move toward their original, undeflected positions (or inwardly toward the connector  14 ) to engage with the dividers  234 . The stops  262  on the housing engagement arms  256  engage the ledges  258  on the divider  234  to form an interference fit. This interference fit resists movement of the sliding latch  242  from force applied by the compressed springs  240  in the direction of arrow  294 . Once contact is made between the sliding latch  242  and the housing  202  at this location, a substantial portion or all of the force from the compressed springs  240  is carried by the housing  202  via the ledges  258  on the dividers  234  and not by the stops  24  and wedge-shaped tabs  272 . Advantageously, the force from the compressed springs  240  is not carried appreciably by the connector  14  and the connector latch  244 . This arrangement is believed to prolong the life of the connector  14  and/or prevent physical damage to the connector  14  over time. 
     With reference to  FIG.  19   , while the fiber optic adapter  200  resists unintentional, inadvertent removal of the connector  14  when it is in the latched position (shown in  FIG.  18   ), a technician can remove the connector  14  from the fiber optic adapter  200 . Removal includes moving the wedge-shaped tabs  272  of the connector latch  244  from their interference position with the stops  24  on the plug frame  20  and withdrawing the connector  14  from the fiber optic adapter  200  along the direction of arrow  294 . To move the wedge-shaped tabs  272  out of the interference position with the stops  24 , the technician slides the shell  22  relative to the plug frame  20  in the direction of arrow  294 . The shell  22  engages the ears  278  pushing them outwardly. This movement pushes the wedge-shaped tabs  272  outward relative to the stops  24 , as shown. This outward motion of the wedge-shaped tabs  272  also moves the protrusions  276  outwardly to engage the housing engagement arms  256  through the through-slot  268 . This movement disengages the housing engagement arms  256  from the ledges  258 , and the sliding latch  242  is free to move in the direction of arrow  294 . Once the wedge-shaped tabs  272  clear the stops  24 , and the sliding latch  242  is freed from ledge  258 , the connector  14  is movable in the direction of arrow  294  and so is removable from the fiber optic adapter  200 . Once the sliding latch  242  is freed from the ledge  258 , the compressed springs  240  apply force in the direction of arrow  294  and may aid a technician in removal of the connector  14  from the adapter  200 . 
     With reference to an exemplary embodiment shown in  FIGS.  20 - 29   , a fiber optic adapter  300  differs from the fiber optic adapters  100  and  200  in that the fiber optic adapter  300  provides a visual indication when a connector  14  (shown in  FIG.  1   ) is improperly installed during installation. The visual indication is separate from any spring-effected movement of the connector within the adapter. In other words, while the fiber optic adapter  300  may provide a spring force that opposes the insertion of a connector, similar to the fiber optic adapters  100  and  200 , described above, the fiber optic adapter  300  also includes an indicator flag that indicates when a connector is properly installed. The indicator flag protrudes from and remains fully extended until the connector is properly latched into the fiber optic adapter  300 , at which point the flag is withdrawn into the adapter. The flag withdrawal is abrupt and occurs only when the connector is at or nearly at the latched position. In effect, the flag provides the technician with a visual go/no-go indication during installation of a connector. The interaction of the fiber optic adapter  300  with the connector  14  is described with reference to  FIGS.  23 - 29   . While a simplex connector is shown and described, embodiments of the invention are not limited to use with simplex connectors. For example, it is contemplated that fiber optic adapters according to embodiments may be used with duplex and quad connectors. Further, while SC connectors are shown, embodiments are not limited to SC connectors, as MU connectors are contemplated. 
     With reference to  FIGS.  20 ,  21 , and  22   , in one embodiment, the fiber optic adapter  300  includes a housing  302  having two portions  304 ,  306  which are joined together, for example, at a joint  310  (a snap fit construction is shown). The housing  302  is generally rectangular in shape having sides  312 ,  314 ,  316 , and  318  and opposing ends  320  and  322 . The ends  320  and  322  define cavities  324  and  326 , respectively, for receiving a respective one of connectors  14 ,  16  (shown in  FIG.  1   ). One of the sides, such as side  312 , includes alignment slots  130 ,  132  that open to a respective cavity  324 ,  326  and receive a portion of the connector  14 ,  16 . The slots  130 ,  132  ensure that the connector  14 ,  16  is inserted in a predetermined orientation. The fiber optic adapter  300  may be a female-to-female type adapter to receive connectors  14 ,  16  at each end  320  and  322 . Although not shown, the end  322  may be provided with a male connector. With the male connector at end  322  and the cavity  324  at the opposing end  320 , the fiber optic adapter  300  may be a male-to-female type adapter. 
     Further, one end, such as end  320 , includes one or more dividers  334  that defines passageways  338  adjacent the cavity  324 . In the exemplary embodiment shown, there is a pair of passageways  338  that are spaced apart by the cavity  324 . The dividers  334  include a through-slot  368  (shown in  FIG.  21   ) that provides an opening between the cavity  324  and the passageway  338 . An indicator flag  332  extends from the passageways  338 . Each of the indicator flags  332  is movable in the passageway  338  from an extended position as is shown in  FIG.  20   , in which each indicator flag  332  is at its maximum extension from the housing  302 , to a retracted position, which is shown in  FIG.  26   , in which the indicator flags  332  are fully within the housing  302 . However, it will be appreciated that in the retracted position, there may be a minimal portion of the indicator flag  332  either visible in the passageway  338  or a minimal portion of the indicator flag  332  may extend beyond the housing  302  (due to dimensional tolerances and play during design and manufacturing of the adapter  300 ). The indicator flags  332  may be a different color than the color of the housing  302 . For example, the indicator flags  332  may be red while the housing  302  is white or gray. The retraction of the indicator flags  332  from the extended position to the retracted position occurs when a connector is fully inserted and latched in the cavity  324 . The retraction of the indicator flags  332  is described with reference to  FIGS.  23 - 26   . Each of the indicator flags  332  further includes a pair of shoulders  356  and cooperate with the passageways  338  in the housing portion  304  to stop outward movement of the indicator flags  332 . 
     With continued reference to  FIGS.  20 ,  21 , and  22   , sides  316 ,  318  of the housing portion  304  may include silos  336  that generally project from the side  316  of the housing portion  304 . The silos  336  may form cavities  352  that receive one or more springs  340 . In cooperation with a sliding latch  342 , the springs  340  provide resistance to insertion of a connector into cavity  324 . The sliding latch  342  includes a rectangular shaped frame  360  from which nipples  354  extend to receive ends of springs  340 . In that regard, the springs  340  are compressed when a connector is inserted into the cavity  324  and contacts the frame  360 . When the spring  340  are compressed, the force from the compressed springs may be sufficient to move the sliding latch  342  and may also push a connector outwardly from within the cavity  324  if the connector is not fully inserted to a locked position in the fiber optic adapter  300 . In the embodiment shown, two springs  340  are engaged with the sliding latch  342  and are shown spaced apart at the sides  316 ,  318  in respective silos  336  of the housing  302 . Embodiments of the invention are not limited to two springs  340 . That is, it is within the scope of the present disclosure that alternate number of springs  340  may be used. The spring force may be sufficient to move a connector in an outward direction from the cavity  324  by a distance sufficient to degrade or prevent optical transmission in fiber optic cable  10 . An installer may therefore identify poor optical transmission during a transmission quality check following installation. 
     With reference to  FIGS.  21  and  22   , the housing  302  contains one or more additional springs  348  coupled to the sliding latch  342  via nub  328  at one end and to the indicator flags  332  at the other end via nub  328  on the flag  332 . In that regard, the springs  348  are extended along an extension axis  358  when a connector is inserted into the cavity  324 . When extended, the springs  348  are configured to withdraw the indicator flags  332  when the connector is fully inserted to a locked position in the fiber optic adapter  300 . Retraction of the indicator flags  332  is described in greater detail below. Each of the indicator flags  332  includes a stop  362  (shown in  FIGS.  23 - 29   ) extending inwardly which are engaged to permit extension of the springs  348 . In the embodiment shown, two springs  348  are engaged with the sliding latch  342  and are shown spaced apart at the sides  316 ,  318  in respective silos  336  of the housing  302 . Embodiments of the invention are not limited to two springs  348 . It is within the scope of the present disclosure that alternate number of springs  348  may be used. 
     In one embodiment, the silos  336  of the housing portion  306  and channels  366  in indicator flags  332  define the cavities  352  that receive the springs  348 . The cavities  352  also receive springs  340  and include a surface  364  against which one end of the springs  340  may be compressed during insertion of a connector. The springs  340  are compressible between the sliding latch  342  and the surface  364  during insertion of a connector into cavity  324  with the cavities  352  and nipples  354  defining a compression axis  384  for each spring  340 . Compression axis  384  of the springs  340  may align with extension axis  358  of the springs  358  or they may be offset from one another. This is shown in  FIG.  21   , which depicts the fiber optic adapter  300  with springs  340  in a compressible position. The sliding latch  342 , compression springs  340 , extension springs  348 , and indicator flags  332  are movable in the housing  302 , as is schematically shown in  FIGS.  23 - 26   , described below. 
     With reference to  FIGS.  21  and  22   , in addition to the springs  340  and sliding latch  342 , the housing  302  contains a connector latch  344  abutting a sleeve holder  346 . The connector latch  344  may be coupled to the sleeve holder  346 . The connector latch  344  and sleeve holder  346  collectively house a sleeve  350  in receptable  374 . The connector latch  344  and the sleeve holder  346  are configured to couple connectors (e.g., connectors  14  and  16  of  FIG.  1   ) within cavities  324  and  326 , respectively. By way of example,  FIGS.  23 - 26    illustrate a connector  14  being inserted into cavity  324 , as is described below. The rectangular frame  360  of the sliding latch  342  receives the connector latch  344 . 
     With continued reference to  FIGS.  21  and  22   , in the exemplary embodiment, the connector latch  344  is substantially the same as connector latches  144  and  244  described above and is contained in the housing portion  304  proximate the cavity  324 . The connector latch  344  is configured to latch a connector in the cavity  324  to the housing  302 . In that regard, the connector latch  344  includes a pair of engagement arms  370  having wedge-shaped tabs  372 . Wedge-shaped tabs  372  face inwardly and cooperate with a connector to capture the connector in the cavity  324 . The engagement arms  370  also include a protrusion  376  extending outwardly from each arm  370  opposite the wedge-shaped tabs  372 . As shown in  FIG.  21   , the protrusions  376  are positioned proximate the indicator flags  332  and are movable outwardly to engage the stops  362  of the indicator flags  332  during insertion of a connector into cavity  324 , as is described below. In addition, an ear  378  extends laterally outward (e.g., toward the sides  312  and  314  of the housing portion  304 ) from the arm  370  between the protrusion  376  (and may be generally perpendicular to the protrusions  376 ) and the tabs  372  and is configured to contact a shell of a connector. 
     The sleeve holder  346  is received in the housing portion  306  and abuts the connector latch  344 . The sleeve holder  346  is configured to couple a connector that is inserted into the cavity  326 . In that regard, the sleeve holder  346  includes engagement arms  380  having wedge-shaped stops  382  much like engagement arms  370  and wedge-shaped tabs  372  of the connector latch  344 . The wedge-shaped tabs  372  engage stops on the plug frame of a connector. The sleeve holder  346  and the connector latch  344  collectively define the receptacle  374  that receive the sleeve  350 . 
     With reference to  FIGS.  23 - 26   , insertion of a connector  14  into the fiber optic adapter  300  is shown. In  FIG.  23   , an installer inserts the connector  14  according to arrow  386  into the cavity  324  on the end  220  of the fiber optic adapter  200 . This may occur before or after insertion of a connector into the cavity  326  (not shown). In the cavity  324 , the connector  14  contacts the connector latch  344  at the engagement arms  370 . Although not shown, initial contact of the shell  22  is at the ears  378 . With the connector  14  in this position, the springs  340  are extended and the springs  348  are generally relaxed, and the sliding latch  342  is at its fully extended, unlatched position. Although not shown, the springs  340  may be initially compressed though that compression may be minimal. And, the springs  348  may be initially extended though the amount may be minimal. Thus, the springs  340  and  348  are in a generally relaxed state. The indicator flags  332  extend from the passageways  338  when the sliding latch  342  is in its fully extended position. In this position, the flags  332  provide a visual indication that the connector  14  is not properly installed. 
     With reference to  FIG.  24   , when the installer pushes the connector  14  further into the cavity  324  (according to arrow  386 ), the engagement arms  370  of the connector latch  344  are deflected outwardly toward the sides  316 ,  318 . In that regard, the forcible insertion of the connector  14  pushes the shell  22  against the ears  378  thereby pushing the tabs  372  apart. As the wedge-shaped tabs  372  are moved outwardly, the protrusions  376  of the engagement arms  370  are deflected into through-slot  368  and into an interference position with the stops  362 . In the position shown in  FIG.  24   , the connector  14  may initially contact the frame  360  of the sliding latch  342  though the springs  340  may not be appreciably compressed by that contact. The springs  348  may not appreciably extend from their original relaxed state, and the indicator flags  332  remain extended to indicate that the connector  14  is not yet properly installed. The ferrule  26  of the connector  14  may extend slightly into a recess formed by the sleeve  350 . 
     With reference to  FIG.  25   , further forcible insertion of the connector  14  into the cavity  324  (along the direction of arrow  386 ) pushes on the sliding latch  342 , compresses the springs  340 , and extends the springs  348 . The indicator flags  332  remain fully extended from the housing  302  though they may move slightly if there is a small gap between the protrusion  376  and stop  362 . In particular, as the installer pushes the connector  14  further into the cavity  324 , the plug frame  20  and/or shell  22  contact the frame  360  of the sliding latch  342 . Movement of the sliding latch  342  according to arrow  386  compresses the springs  340  and extends the springs  348 . Even though the springs  348  are extended, the indicator flags  332  remain substantially fully extended because the protrusions  376  are in contact with the stops  362 . This prevents movement of the indicator flags  332  and permits extension of the springs  348 . Thus, with the indicator flags  332  fully extended, the fiber optic adapter  300  visually indicates that the connector  14  is not fully inserted and is unlatched to the fiber optic adapter  300 . 
     With further insertion of the connector  14  into the fiber optic adapter  300  from the position shown in  FIG.  25    to the position shown in  FIG.  26   , a latched/locked position is reached. The indicator flags  332  are withdrawn into the housing  304  indicating that the connector  14  is properly installed in the fiber optic adapter  300 . In this position, the connector  14  is locked to the fiber optic adapter  300 . That is, the connector  14  and the adapter  300  resist their inadvertent separation. To that end, with further movement of the sliding latch  342  in the direction of arrow  386 , the stops  24  of the plug frame  20  move past the wedge-shaped tabs  372 . This permits the engagement arms  370  to spring back toward their undeflected positions (i.e., toward the connector  14 ). The wedge-shaped tabs  372  move to a position in which they form an interference fit to movement of the stop  24  on the plug frame  20  in a direction indicated by arrow  394 . The stops  24  are then positioned between the wedge-shaped tabs  372  and the sleeve holder  346  and are effectively trapped in the fiber optic adapter  300 . Thus, the connector  14  is latched to the fiber optic adapter  300  at this position. This configuration resists inadvertent, unintentional removal of the connector  14  from the fiber optic adapter  300 . 
     In the exemplary embodiment, once the engagement arms  370  are released and move toward their original, undeflected positions, to lock the connector  14  to the fiber optic adapter  300 , the corresponding protrusions  376  disengage from contact with the stops  362 . The springs  348 , which are extended, are then permitted to retract and pull the indicator flags  332  into the housing  302 . This movement is sufficient to fully retract the indicator flags  332 . Because the flags  332  are fully retracted, the technician knows that the connector  14  is properly installed and locked in the fiber optic adapter  300 . Advantageously, the flags  332  are quickly withdrawn by contraction of the springs  348 . Flags  332  have two positions during installation of a connector, an extended position when a connector is not fully installed and a retracted position when the connector is fully installed and latched within the adapter  300 . The flags  332  do not have an intermediate position. With only two positions, the technician is able to easily verify that the connector  14  is or is not properly installed. In the latched position shown in  FIG.  26   , the springs  340  are compressed and the springs  348  are in a relaxed state. 
     With reference to  FIG.  27 - 29   , while the fiber optic adapter  300  resists unintentional, inadvertent removal of the connector  14  when it is in the latched position (shown in  FIG.  26   ), a technician can remove the connector  14  from the fiber optic adapter  300 . Removal includes moving the wedge-shaped tabs  372  of the connector latch  344  from their interference position with the stops  24  on the plug frame  20  and withdrawing the connector  14  from the fiber optic adapter  300 . To move the wedge-shaped tabs  372  out of the interference position with the stops  24 , the technician slides the shell  22  relative to the plug frame  20  in the direction of arrow  394 . The shell  22  engages the ears  378  pushing them outwardly relative to the stops  24 . This also pushes the wedge-shaped tabs  376  outwardly relative to stops  24 . As shown in  FIG.  27    compared to  FIG.  28   , with relative sliding movement of the shell  22  relative to the plug frame  20  according to arrow  394 , the wedge-shaped tabs  372  moves the protrusions  376  into an interference position with respect to stops  362  of the indicator flags  332 . In  FIG.  28   , the indicator flags  332  may therefore partly extend from the passageways  338  when the stops  362  engage the protrusions  376 . 
     With reference to  FIG.  28   , as the connector  14  is moved further outwardly, the sliding latch  342  moves with the connector  14 , because the springs  340  begin extending from their compressed positions shown in  FIG.  26    and push the sliding latch  342  outwardly. This may assist the removal of the connector  14  from the fiber optic adapter  300 . The indicator flags  332  may move with the movement of the sliding latch  342  until stops  362  contact the protrusions  376 . The flags  332  may therefore only partly extend from the housing  304  when the stops  362  contact protrusion  376 . 
     As shown in  FIG.  29   , once the wedge-shaped tabs  372  clear the plug frame  20 , they return to their undeflected position. The protrusions  376  disengage from the stops  362  and the indicator flags  332  may return to their fully extended positions and the sliding latch  242  is push to its extended position. The indicator flags  332  therefore indicate that the connector  14  is not properly installed. 
     While the present disclosure has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination within and between the various embodiments. 
     Additional advantages and modifications will readily appear to those skilled in the art. The present disclosure in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the present disclosure.