Abstract:
A method and apparatus for detecting plug types capable of being inserted into a socket includes a processor, a housing having a plug receiving cavity for one or more plug types including a proper and improper plug type. Actuators are associated with the housing, and are coupled to switches electrically coupled to the processor. A first actuator is capable of contacting the proper and improper plug type and a second actuator is capable of contacting only the proper plug type. Switches may provide a signal to the processor when the improper and proper plug type has been plugged into the socket.

Description:
FIELD OF THE INVENTION 
   The present invention generally relates to electrical connectors. More particularly, the present invention is related to connectors for computers and related electronic devices which can detect the presence of an improperly inserted plug. 
   BACKGROUND OF THE INVENTION 
   Electrical connectors are extremely diverse in type and number. However, standardization within certain industries such as, for example, the communications and computer industries has driven manufacturers to adopt the use of standard connectors in many applications. Interoperability between products made by a diversity of manufacturers within these and other industries is so important, particularly for network and telephone interfaces, that the use of proprietary or non-standard connectors for standard communications interfaces could likely compromise the marketability of products containing them and would be largely unthinkable. 
   As the computer and communications worlds have converged, the demand for interconnection between computers and, for example, the public phone system have driven computer makers to use standard connectors to facilitate such interconnection and the rich content available therefrom. Such standard connectors are also rugged, multi-sourced, reliable, and inexpensive. The RJ-series connector, such as the RJ-11 and RJ-45 connectors, represents such a standard connector. RJ stands for “Registered Jack” and is specified according to the standards called out in U.S. Federal Communications Commission rules and regulations, 47 C.F.R. 68. The RJ series connectors were originally developed by AT&amp;T as a modular connection solution for telephone handsets and wall plugs and are now used by almost all telephone companies throughout the world. The RJ connectors are configured based on a connection form factor and an actual number of connections. For example, the RJ-11 and RJ-12 are the same size, e.g. A six connection form factor, with the RJ-11 having four connections and the RJ-12 having six connections. The connection protocol is typically center oriented so that modifications can be made without disturbing existing service. Although now used for many different applications, the most important use for the RJ series connectors, particularly the RJ-11 connector, is the interconnection of telephones, modems, and computers with telephone lines. Accordingly, stringent standardization of connectors has been established to enable compatibility and interoperability. Due to the simplicity of the connector design, the reliability of the connections, and the fact that the connectors are manufactured under established standards, RJ-series connectors are used extensively in the computer industries and in other industries where communication over telephone lines or standard interconnection is required. 
   The standard RJ-series modular connector includes a plug or contact block and a jack or socket having a certain number of mating contacts. The plug includes a small block shaped body typically having pressure activated blades which can be crimped on to a cable, such as a telephone line typically having individual conductors. The crimping action provides a connection between the individual conductors and the contact surface of the blade which is then positioned to contact a corresponding spring contact generally housed within the jack or socket. The outside of the body is molded with a flexible retention clip or key that allows the plug to be secured within the socket. A portion of the clip extends outside the plug/jack mating area to allow the plug to be easily disconnected by depressing the clip and pulling the plug. 
   The socket can be integrated into a circuit board and can be accessed through a port in the housing or enclosure of associated equipment or can be molded directly into an enclosure and wired to a circuit board. The socket may be mechanically configured to receive the plug and contains flexible contact wires aligned with and biased against corresponding contacts on the plug to complete the electrical connection between the plug and the electrical apparatus. 
   The interior surface of the socket includes a receiving notch for accepting the retention clip of the plug so as to mechanically secure the plug within the socket. Once the retention clip has snapped into place within the receiving notch through a flexing action of the retention clip away from the body of the plug, the plug is firmly held in place providing secure mechanical and electrical coupling. To remove the plug, the retention clip is manually flexed back towards the body of the plug to release the retention clip from the notch, enabling manual removal of the plug from the socket. While the basic characteristics and operation of the RJ-11 plug has been described herein, other RJ series plug and jacks are used extensively in electronic, computer, and communications devices and operate in the same basic manner. 
   The RJ-45 modular connector, for example, is used extensively for network interface interconnections and possesses many of the same basic characteristics of the RJ-11 plug described previously herein. The RJ-45 connector has a larger width dimension than the RJ-11 and is configured to facilitate eight connections. The RJ-11 is configured for four connections but has a form factor to accommodate six. It is important to note that perhaps due to legacy compatibility concerns, e.g. concerns that later versions of RJ designs would accept earlier designs, the RJ-45 connector although wider can accommodate an RJ-11 connector. 
   Problems arise however since although the RJ-11 plug may be plugged into an RJ-45 jack, the wiring of the RJ-45 may deviate from normal telephone connection protocol as it typically does for network connectivity commonly associated with modem applications of the RJ-45 form factor. Thus damage due to improper electrical connection is possible. And further, although detection of a properly inserted plug is relatively easy, the detection of an improperly inserted plug is not easily addressed as evidenced by the lack of adequate solutions in the art. 
   Some plugs have been configured to detect the presence of a jack therewithin as described for example in U.S. Pat. No. 5,378,165 issued on Jan. 3, 1995 to Comerci et al (hereinafter “Comerci”). The plug described in Comerci however is configured to detect a properly inserted plug and fails to teach or suggest how to deal with an improperly inserted plug. Comerci further appears to require that the plug be fully inserted before detection can occur. Still further, Comerci requires separate assemblies for the plug housing and detection means leading to increased cost of manufacture and assembly. In U.S. Pat. No. 5,772,466 issued on Jun. 30 1998 to Morin et al. (hereinafter “Morin”), a receptacle connector adapted for mating with at least two types of plug connectors is described. Morin&#39;s receptacle generates a signal when mating with one type connector and does not generate a signal when mating with the other type of connector. The obvious problem with Morin&#39;s approach is that there is no way to distinguish whether the lack of a signal indicates that an improper plug type is plugged into the receptacle or whether the receptacle is simply empty. 
   Thus, it would be desirable in the art for a solution to the abovementioned problems by providing for detection of an improperly inserted plug into a receptacle which can physically accommodate more than one plug type. In addition to detecting the improperly inserted plug it would be further desirable for the detection of a properly inserted plug. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a method and apparatus for detecting one or more plug type capable of being inserted into a socket. In one exemplary embodiment, the apparatus preferably includes a housing having a plug receiving cavity associated with the socket and at least one of the one or more plug type, that is, the plug receiving cavity may be configured to properly accept at least one of several plug types capable of being inserted therewithin, e.g. the proper plug type. The housing may include two or more actuators such that the proper plug type and an improper plug may be detected. Accordingly, a first actuator may be disposed within the plug receiving cavity such that when either the proper or the improper plug type is plugged into the socket the first actuator may be contacted thereby. Likewise, a second actuator may be disposed within the plug receiving cavity such that only when the proper plug type is plugged into the socket the second actuator may be contacted thereby. It should be noted that the one or more plug types may include RJ-11 and RJ-45 plug types, the improper plug type preferably being the RJ-11 plug type and the proper plug type preferably being the RJ-45 plug type. 
   In accordance with an alternative exemplary embodiment of the present invention, two or more actuators associated with the housing are preferably associated with two or more switches which, as will be appreciated by one skilled in the art can be normally open or normally closed. The switches may be electrically coupled to a processor such that, for example, the first switch associated with the first actuators generates a signal both when the proper plug type, e.g. the RJ-45 plug type, and when improper plug type, e.g. the RJ-11 or RJ-12 plug type, is inserted into the socket, which signal may be read by the processor. The second switch associated with the second actuator may also generate a signal only when the proper plug type, e.g. the RJ-45 plug type, is inserted into the socket. Thus the second switch will ultimately be determinative of whether the plug type is proper or improper, e.g. if the first switch is activated and the second switch is not activated an improper plug insertion has taken place. It should be noted that processor may be dedicated to the purpose of plug detection or may be a general purpose and/or central processor associated with equipment to which the plug types are connected to. 
   In accordance with yet another alternative exemplary embodiment of the present invention, the method for detecting one or more plug type capable of being inserted into a socket may include configuring a housing having a plug receiving cavity associated with the socket and at least the proper plug type with two or more actuators associated with the housing. The actuators may be formed, for example, during manufacture of the housing and may be constituted preferably as, for example, tabs pointing either toward or away from the opening of the cavity. As in other exemplary embodiments, the plug types may include a proper plug type and an improper plug type, the proper plug type preferably being the RJ-45 plug type, the improper plug type being the RJ-11 or RJ-12 plug type. The first actuator may be disposed within the plug receiving cavity such that it is capable of contacting both the proper, e.g. RJ-45 and the improper plug type, e.g the RJ-11 or RJ-12 plug type, when either the proper or the improper plug type is plugged into the socket. A second actuator may further be disposed within the plug receiving cavity such that it is capable of contacting only the proper plug type, e.g. the RJ-45 plug type, when the one or more plug type is plugged into the socket. Further in accordance with the present exemplary embodiment, the method may further include actuating a first switch with the first actuators, with the first switch being coupled electrically to a processor as previously described herein, and generating a first signal readable by the processor both when the proper and when the improper plug type are inserted into the socket. Likewise, a second switch may be actuated with the second actuator, the second switch also coupled electrically to a processor, and a second signal may be generated with the second switch only when the proper plug type is inserted into the socket. 
   It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
       FIG. 1  is a diagram illustrating an exemplary RJ-45 receptacle and exemplary RJ-11 and RJ45 plug types in accordance with the prior art; 
       FIG. 2  is a diagram illustrating the exemplary RJ-45 receptacle and exemplary RJ-11 and RJ45 plug types of  FIG. 1  plugged in accordance with the prior art; 
       FIG. 3A  is a diagram illustrating an exemplary receptacle having actuator tabs in accordance with various exemplary embodiments of the present invention; 
       FIGS. 3B  is a diagram illustrating an exemplary receptacle having actuator tabs in accordance with various alternative exemplary embodiments of the present invention; 
       FIG. 4  is a diagram illustrating an exemplary receptacle with a proper and improper plug type making contact with actuator tabs in accordance with various exemplary embodiments of the present invention; 
       FIG. 5  is a diagram illustrating an exemplary receptacle with actuator tabs and a switch schematic in accordance with various exemplary embodiments of the present invention; 
       FIG. 6A  is a diagram illustrating various exemplary actuator tab and switch configurations in accordance with various exemplary embodiments of the present invention; and 
       FIG. 6B  is a schematic diagram illustrating exemplary switch configurations with corresponding truth tables in accordance with various exemplary embodiments of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In accordance with various exemplary embodiments, the present invention solves the problem of detecting an improperly inserted plug by providing specific detection of the improperly inserted plug type. Such detection is made possible by factors including standard form factors and the fact that a specific type of improper plug type is normally expected. 
   Thus, as can be seen from  FIG. 1 , a conventional plug and receptacle scenario  100  is shown. Receptacle  110  is a typical RJ-45 receptacle or jack configured most probably for multi-line telephone or network applications. Receptacle  110  is provided with a plug receiving cavity  111 , which is configured to receive RJ-45 plug  120 . In normal operation, RJ-45 plug  120  is fitted within plug receiving cavity  111  by holding either the body of the plug or conductor  123 , which usually contains multiple conductors crimped as described hereinabove. RJ-45 plug  120  is then pushed entirely into plug receiving cavity  111  until restraining tab  122  fits within tab cavity  114  and RJ-45 plug contacts  125  come into contact with receptacle contacts  115 . Because restraining tab  122  is spring biased at spring joint  124 , the tab should “click” into place and thus provide solid contact as illustrated in FIG.  2 . To remove RJ-45 plug  120 , removal tab  121  may be pressed down at notch  112  to release restraining tab  122  from tab cavity  114  and remove RJ-45 plug  120 . In an improper scenario, RJ-11/12 plug  130  is fitted within plug receiving cavity  111  by holding either the body of the plug or conductor  133 . Because the height form factor is the same according to RJ-45 and RJ-11/12 standards, RJ-11/12 plug  130  may be pushed entirely into plug receiving cavity  111  until restraining tab  132  fits within tab cavity  114  and RJ-11/12 plug contacts  135  come into contact with a subset of receptacle contacts  115 . As above, because restraining tab  132  is spring biased at spring joint  134 , the tab should “click” into place and thus provide solid thought improper contact also illustrated in FIG.  2 . To remove RJ-11/12 plug  130 , removal tab  131  may be pressed down at notch  112  to release restraining tab  132  from tab cavity  114  and remove RJ-11/12 plug  130 . It is important to note that serious problems may arise since typical applications for RJ-45 may not be telephone oriented, thus plugging an RJ-11/12 plug into an RJ-45 jack may cause unspecified electrical damage to either or both of the equipments connected to the plug side or jack side. 
   To alleviate the problem of potential electrical damage to equipment, exemplary receptacle scenario  300  is shown in FIG.s  3 A and  3 B. As shown in  FIG. 3A , exemplary receptacle  310  in accordance with various exemplary embodiments of the present invention may be fitted with exemplary actuator tab  311  and  312  for contacting both proper and improper plug types. It should be apparent to one skilled in the art that exemplary actuator tabs  311  and  312  may be formed during manufacture into, for example, plastic or whatever material is suitable for use in receptacle  310  provided the material is relatively springy and can withstand repeated flexing such as, for example, plastic or the like. It should be noted that actuator tabs  311  and  312  are shown for illustrative purposes slightly downward. Since it would be an obvious impediment to plugging for actuator tabs  311  and  312  to be positioned downward within plug receiving cavity  320 , actuator tabs  311  and  312  are preferably flush with the side of plug receiving cavity  320  and may additionally be provided with contact cams  313  and  314  respectively. Thus when a properly or improperly inserted plug type is inserted into plug receiving cavity  320 , one or more of contact cams  313  and  314  may contact the plug and either actuate a proximal external switch or may be integrated into a switch mechanism. Alternatively, as shown in  FIG. 3B , actuator tabs  315  and  316  may be formed during manufacture directed in the plugging direction, that is, the free ends of actuator tabs  315  and  316  may be pointed toward the inside of plug receiving cavity  320  to ensure they don&#39;t interfere with plugging action. As described herein above with regard to actuator tabs  311  and  312 , actuator tabs  315  and  316  may further be configured with contact cams  317  and  318  respectively. 
   In a simple yet elegant manner, the present invention in its various exemplary embodiments, may be used to address the above described problems and detect the presence of both a proper and improper plug type as shown in FIG.  4 . Plugging scenario  400  illustrates receptacle  310  with RJ-45 plug  120  inserted in proper fashion therewithin. Note that as shown in exemplary detail  401 , both exemplary actuators  311  and  312  are activated when RJ-45 plug  120  is properly inserted. In exemplary detail  402 , RJ-11/12 plug  130  is inserted in improper fashion into receptacle  310 . Note that as shown, only exemplary actuator tab  312  is activated while exemplary actuator tab  311  remains un-activated. It should be apparent to one skilled in the art that while exemplary actuator tabs  311  and  312  are shown in a representative manner, any number of possible direct switch or mechanical switch actuators may be used without departing from the scope of the invention. Further, as previously described, exemplary actuator tabs  311  and  312  are shown as biased downward into plug receiving cavity  320  for illustrative purposes, exemplary actuator tabs  311  and  312  are, in various exemplary embodiments, preferably flush with the side wall of receptacle  310  and may further be provided with activation cams or the like to provide actuation pressure when either a proper or improper plug type is inserted. 
   Accordingly, as can be seen in  FIG. 5 , exemplary actuator tabs  311  and  312  may preferably be coupled mechanically to a switch such as, for example, SW 1   501  and SW 2   502  (shown as normally open) or like logic elements preferably of the momentary type meaning that the switch contacts stay activated as long as the mechanical activation condition, e.g. insertion of the plug, is present and are inactivated when the mechanical activation condition is removed. It will be appreciated in the art that other types of mechanical and non-mechanical actuation may be used without departing from the scope of the invention. It will further be appreciated that in accordance with various exemplary embodiments of the present invention, normally open or normally closed switches may be used depending on the exact mechanical configuration desired or other considerations like part costs and the like. 
   It should be noted that as described previously herein, exemplary actuator tabs  311  and  312  may be used to actuate an external switch or may be an actual part of a switch element.  FIG. 6A  illustrates several exemplary switch and switch actuator configurations in accordance with various exemplary embodiments of the present invention. In configuration  610 , for example, exemplary actuator tabs  311  and  312  are formed as tabs during the manufacture of receptacle housing  310 . Switch element  611  is fixed either on receptacle  310  or externally such that when a proper or improper plug type is inserted one or more of exemplary actuator tabs  311  and  312  communicate mechanically with the contact arm  612  of switch element  611  closing or opening the switch contacts depending on whether the contacts of switch element  611  are normally open or normally closed. In configuration  620  switch element  622  is fixed to receptacle  310  or may be fixed externally. In either case, switch contact arm  621  may be elongated such that it may be used to directly contact an proper or improper plug type during insertion. Activation cam  623  may further be associated with switch contact arm  621  to ensure proper contact and to allow switch contact arm  621  to be positioned closer to the side of receptacle  310  and thus be further out of the way of interfering with plug insertion. Configuration  630  shows exemplary actuator tabs  315  and  316  manufactured such that they are flush with the side of receptacle  310  with one or more of activation cams  317  and  318  positioned to engage a proper or improper plug type. Once engaged, one or more of activation cams  317  and  318  may be used to press tabs  315  and/or  316  into contact with switch  631 . Switch  631  may be a button switch or the like and may be fixed to receptacle  310  or may be fixed to an external structure in proximity to receptacle  310 . In yet another configuration  640 , actuator tabs  311  and  312  by way of activation cams  313  and  314  may be pressed into engagement with switch  641  during plug insertion. Again, switch  641  may be a button or any other suitable type of switch element which can be activated by the mechanical act of plug insertion. 
   As will be appreciated by one skilled in the art and as is shown in  FIG. 6B , several switching scenarios may be used in accordance with various exemplary embodiments of the present invention. In scenario  650 , SW 1   651  and SW 2   652  are preferably normally open, single pole single throw (SPST) momentary switches or equivalent. During inactive quiescent state, logic levels as seen at input pins  655  and  656  of processor  657  should be pulled high to V cc  through pull up resistors  653  and  654 . When either of SW 1   651  or SW 2   652  are closed, the corresponding logic levels as seen at input pins  655  or  656  of processor  657  should be pulled low to ground potential or V ss . In yet another exemplary scenario  660 , SW 1   661  and SW 2   662  are SPST normally closed momentary switches or equivalent. When either of SW 1   661  and SW 2   662  are opened during plugging, corresponding logic levels as seen at input pins  665  or  666  of processor  667  should be pulled high to V cc  through pull up resistors  653  and  654 . When SW 1   661  or SW 2   662  are closed again, the corresponding logic levels as seen at input pins  655  and  656  of processor  667  should be pulled low to ground potential or V ss . 
   A summary of logical states corresponding to the possible proper and improper plug type insertion associated with scenarios  650  and  660  is shown in FIG.  6 B. Therein it can be seen that for scenario  650 , state table  670  shows that with no plugs inserted both logic levels associated with SW 1   651  and SW 2   652  are high. For a proper RJ-45 plug type insertion, both SW 1   651  and SW 2   652  will be activated and a low state will be asserted to processor  657  on both pins  655  and  656 . For an improper RJ-11/12 plug insertion, only SW 2   652  will be activated causing a low logic level at pin  656  of processor  657 . Conversely, for scenario  660 , state table  680  shows that with no plugs inserted, both logic levels associated with SW 1   661  and SW 2   662  are low. For a proper RJ-45 plug type insertion, both SW 1   661  and SW 2   662  will be activated and a high state will be asserted to processor  667  on both pins  665  and  666 . For an improper RJ-11/12 plug insertion, only SW 2   662  will be activated causing a low logic level at pin  666  of processor  667 . It should be noted that exemplary processors  657  and  667  may be either specialized processors for the detection of plug type insertion or may be read by the main processor of a computer or any similar processor which relies on the detection of proper and improper plug type insertion such as, for example, a communications processor. It should further be noted that the detection of proper and improper plug type insertion may be useful to low and/or high level software such as network communications software, socket-type software, hot plug software, driver software or the like such that electrical power to the plug may be inhibited until proper plug insertion is detected. Plug removal may also be detected such that error messages may be generated and communications suspended without data loss. It will be appreciated that error messages may include pop-up software windows which indicate that the improper plug has been inserted, and may further contain instructions, e.g. remove the improper plug and replace it with the proper plug, or the like. 
   It is believed that plug type detection in accordance with various exemplary embodiments of the present invention and many of its attendant advantages will be understood by the forgoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.