Patent Publication Number: US-2010130038-A1

Title: Dummy terminal

Description:
This application is a divisional of application Ser. No. 10/580,539, filed Mar. 19, 2007, which is a 371 of international Application No. PCT/JP2004/017819, filed on Nov. 24, 2004. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a dummy terminal designed to be used instead of a connector terminal attached to an end of a signal transmission cable, and inserted in a lockable manner into a connector-terminal socket originally intended to insertingly receive the connector terminal 
     BACKGROUND ART 
     Heretofore, in an intercommunication system, a transmission cable has been used for transmitting and receiving various signals. This transmission cable is connected to a connector-terminal socket of a communication or communication-relay apparatus using one of connector terminals attached to respective opposite ends of the transmission cable. In connection with diversification in communication means/systems and increase in communication volume, some communication or communication-relay apparatuses have a large number of connector-terminal sockets. 
     In a communication network, for example, LAN (Local Area Network) based on TCP/IP (Transmission Control Protocol/Internet Protocol), a hub connectable with a large number of connector terminals of LAN cables is used for interconnecting a plurality of computers serving as communication terminal units. 
     From a practical standpoint, it is a rare case that all of the connector-terminal sockets of the hub are in connected relation with LAN-cable connector terminals. Further, in conjunction of installation of new computers, relocation of existing computers, network reconstruction, etc., LAN-cable connector terminals are often disconnected and re-connected from/to the hub. This operation involves a problem that a connector terminal is erroneously inserted into an improper or unauthorized connector-terminal socket which has no connector terminal connected thereto, to cause a failure of the communication network. 
     The connection of LAN cables in a communication network is typically managed by a network administrator. In some cases, the operation for connecting LAN-cable connectors to the hub is performed by a plurality of network administrators or a network administrator and assistant staffs, for various reasons. This operation involves a problem that a connector terminal is erroneously inserted into an unauthorized connector-terminal socket to cause a failure of the communication network, due to the lack of means for distinguishing between authorized connector-terminal sockets and unauthorized connector-terminal sockets on an administrator-by-administrator basis. 
     DISCLOSURE OF THE INVENTION 
     In view of the above circumstances, it is an primary object of the present invention to provide a dummy terminal capable of being inserted in a lockable manner into a connector-terminal socket, instead of a cable connector terminal, so as to prevent a cable connector terminal from being erroneously inserted into an improper or unauthorized connector-terminal socket which has no cable connector terminal connected thereto. 
     It is an another object of the present invention to provide a dummy terminal capable of being inserted in a lockable manner into a connector-terminal socket, instead of a cable connector terminal, while allowing each network administrator to distinguish whether or not the connector-terminal socket is an authorized connector-terminal socket. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  1 , according to a first aspect of the present invention, there is provided a dummy terminal designed to be inserted into a connector-terminal socket originally intended to insertingly receive a connector terminal attached to an end of a signal transmission cable. This dummy terminal comprises a dummy terminal body adapted to be inserted into the connector-terminal socket, dummy-terminal engagement means mounted on the dummy terminal body and adapted to be engaged with a connector-terminal latching portion formed in the connector-terminal socket, and dummy-terminal lock means including a lock member which is mounted on the dummy terminal body and adapted to allow the dummy terminal body after being inserted into the connector-terminal socket, to be locked in its engaged state through the dummy-terminal engagement means. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  2 , in the first aspect of the present invention, the dummy-terminal engagement means includes a flexible engagement member having an engagement portion adapted to be engaged with the connector-terminal latching portion. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  3 , in the first aspect of the present invention, the dummy-terminal lock means further includes a screw hole formed in the dummy terminal body, and a set screw threadingly engageable with the screw hole in a detachable manner. The set screw is adapted to be tightened so as to allow the dummy terminal body to be locked in the engaged state, and to be loosened so as to allow the dummy terminal body to be released from the lock-in state. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  4 , in the first aspect of the present invention, the lock member of the dummy-terminal lock means is swingably mounted on the dummy terminal body. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  5 , according to a second aspect of the present invention, there is provided a dummy terminal designed to be inserted into a connector-terminal socket originally intended to insertingly receive a connector terminal attached to an end of a signal transmission cable. This dummy terminal comprises a dummy terminal body adapted to be inserted into the connector-terminal socket, and dummy-terminal release means. The dummy terminal body has a base, an upstanding segment extending upward from the base, an engagement segment which extends approximately parallel to the base, and has a distal end formed as an engagement portion adapted to be engaged with and latched by a connector-terminal latching portion formed in the connector-terminal socket and a proximal end connected to the upstanding segment. The dummy-terminal release means is adapted to release a latched state of the dummy terminal body after being inserted into the connector-terminal socket. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  6 , in the second aspect of the present invention, the dummy-terminal release means includes a screw hole formed in the dummy terminal body, and a set screw threadingly engageable with the screw hole in a detachable manner. The set screw is adapted to be loosened so as to allow the dummy terminal body to be placed in the latched state, and to be tightened so as to allow the dummy terminal body to be released from the latched state. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  7 , according to a third aspect of the present invention, there is provided a dummy terminal designed to be inserted into a connector-terminal socket originally intended to insertingly receive a connector terminal attached to an end of a signal transmission cable. This dummy terminal comprises a dummy terminal body adapted to be inserted into the connector-terminal socket, and dummy-terminal lock means mounted on the dummy terminal body. The dummy terminal body has a base, an upstanding segment extending upward from the base, an engagement segment which extends approximately parallel to the base, and has a distal end formed as an engagement portion adapted to be engaged with a connector-terminal latching portion formed in the connector-terminal socket and a proximal end connected to the upstanding segment. The dummy-terminal lock means is adapted to allow the dummy-terminal body after being inserted into the connector-terminal socket, to be locked in its engaged state through the engagement portion. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  8 , in the third aspect of the present invention, the dummy-terminal lock means includes a screw hole formed in the dummy terminal body, and a set screw threadingly engageable with the screw hole in a detachable manner. The set screw is adapted to be tightened so as to allow the dummy terminal body to be locked in the engaged state, and to be loosened so as to allow the dummy terminal body to be released from the lock-in state. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  9 , the dummy terminal in either one of the first to third aspects of the present invention includes discrimination means for discriminating between a plurality of connector-terminal socket. 
     In order to solve the above problems and achieve the above objects, as set forth in the appended claim  10 , the discrimination means includes at least one selected from the group consisting of a color sticker, a special screw and a coloring material. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a dummy terminal  10  according to a first embodiment of the present invention. 
         FIGS. 2A to 2C  are detail views showing a dummy terminal body  12  and an engagement member  14  fixedly mounted on the dummy terminal body  12  in the first embodiment. 
         FIGS. 3A and 3B  are detail views showing the dummy terminal body  12  and the engagement member  14  fixedly mounted on the dummy terminal body  12  in the first embodiment. 
         FIGS. 4A and 4B  are detail views showing a thin plate member  13  in the first embodiment. 
         FIG. 5  is a perspective view showing a plurality of connector-terminal sockets  104  of a hub  101  for insertingly receiving a dummy terminal  10  of the present invention. 
         FIG. 6  is an explanatory diagram showing a state before the dummy terminal  10  according to the first embodiment is inserted into one of the connector-terminal sockets  104  of the hub  101 . 
         FIG. 7  is an explanatory diagram showing a state after the dummy terminal  10  according to the first embodiment is inserted into the connector-terminal socket  104 , and locked in its engaged state. 
         FIGS. 8A to 8C  are explanatory diagrams showing various types of special screws. 
         FIG. 9  is a perspective view showing a dummy terminal  10  according a second embodiment of the present invention. 
         FIG. 10  is a top plan view showing the dummy terminal  10  according the second embodiment. 
         FIG. 11  is a side view showing the dummy terminal  10  according the second embodiment. 
         FIG. 12  is a front view showing the dummy terminal  10  according the second embodiment. 
         FIG. 13A  is a perspective view showing a dummy terminal  10  according a third embodiment of the present invention. 
         FIG. 13B  is a partially sectional view showing a state after the dummy terminal  10  according the third embodiment is inserted into the connector-terminal socket  104 . 
         FIGS. 14A and 14B  are, respectively, a side view and a top plan view showing a dummy terminal body  12  in the dummy terminal  10  according the third embodiment. 
         FIG. 15A  is a perspective view showing a dummy terminal  10  according a fourth embodiment of the present invention. 
         FIG. 15B  is a partially sectional view showing a state after the dummy terminal  10  according the fourth embodiment is inserted into the connector-terminal socket  104 . 
         FIGS. 16A and 16B  are, respectively, a side view and a top plan view showing a dummy terminal body  12  in the dummy terminal  10  according the fourth embodiment. 
         FIG. 17  is an explanatory perspective view showing one example of means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the first embodiment. 
         FIG. 18  is an explanatory perspective view showing another example of the means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the second embodiment. 
         FIG. 19  is an explanatory perspective view showing another example of the means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the third embodiment. 
         FIG. 20  is an explanatory perspective view showing another example of the means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the fourth embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     With reference to the drawings, a dummy terminal according to an embodiment of the present invention will now be specifically described. 
     First Embodiment 
     With reference to  FIGS. 1 to 8C , a first embodiment of the present invention will be described below. 
       FIG. 1  is a perspective view showing a dummy terminal  10  according to a first embodiment of the present invention. The dummy terminal  10  comprises a dummy terminal body  12 , a thin plate member  13 , an engagement member  14  and a set screw  30 . The dummy terminal body  12  is generally composed of a grooved frame defined by opposite side walls  12 A,  12 B and top wall  12 C, and a front wall  12 D formed at a front end of the grooved frame. This dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of a target connector-terminal socket. The thin plate member  13  is generally composed of an anchor portion  13 A to be mounted on the front wall  12 D, and a restraint portion  13 B for placing an engaged state of the engagement member  14  under restraint. The engagement member  14  is mounted on the rear end of the grooved frame of the dummy terminal body  12 . The engagement member  14  has an anchor portion  14 A fixedly mounted on the dummy terminal body  12 , a deformable or flexible portion  14 B, an engagement portion  14 C and an engagement release portion  14 D. 
     In the engagement member  14 , the flexible portion  14 B is formed to have a relatively large width, and the engagement release portion  14 D continuous with the flexible portion  14 B is formed to have a width less than that of the flexible portion  14 B. That is, the engagement member  14  is formed with a pair of steps extending in a width direction at approximately the longitudinal center thereof, and the steps serves as the engagement portion  14 C adapted to be engaged with a connector-terminal latching portion formed in the connector-terminal socket. 
       FIGS. 2A to 2C  and  FIGS. 3A and 3B  are detail views showing the dummy terminal body  12  and the engagement member  14  fixedly mounted on the dummy terminal body  12 .  FIGS. 2A ,  2 B and  2 C are, respectively, is a top plan view when viewed from the side of the top wall  12 C of the dummy terminal body  12 , a side view when viewed from the side of the side wall  12 A of the dummy terminal body  12 , and a front view when viewed from the side of the front wall  12 D formed at the front end of the grooved frame defined by the side walls  12 A,  12 B and the top wall  12 C of the dummy terminal body  12 .  FIGS. 3A and 3B  are, respectively, a bottom view when viewed from the side of a bottom opening of the grooved frame defined by the side walls  12 A,  12 B and the top wall  12 C of the dummy terminal body  12 , and a rear view when viewed from the side of the rear end of the grooved frame. 
     Further, the dummy terminal body  12  has a screw-hole defining portion  12 E formed to extend from an inner surface of the front wall  12 D toward an inner space of the grooved frame defined by the side walls  12 A,  12 B and the top wall  12 C of the dummy terminal body  12 . A screw hole  12 F for threadingly receiving the set screw  30  is formed in the front wall  12 D and the screw-hole defining portion  12 E in a direction perpendicular to the front wall  12 D. 
       FIGS. 4A and 4B  are, respectively, a front view and a side view showing the detail of the thin plate member  13 . 
     The thin plate member  13  is formed with a loose hole at approximately the center of the anchor portion  13 A. The restraint portion  13 B is formed to have a thickness greater than that of the anchor portion  13 A so as to reliably place the engaged state of the engagement member  14  under restraint. 
     Each of the dummy terminal body  12 , the thin plate member  13  and the engagement member  14  is primarily made of a synthetic resin having insulating performance and elasticity in addition to excellent formability and cost performance, such as ABS (acrylonitrile-butadiene-styrene) resin or PC (polycarbonate) resin. 
     With reference to  FIGS. 5 to 7 , an operation for inserting the dummy terminal  10  into a connector-terminal socket of a hub  101 , and locking in an engaged state of the dummy terminal  10  will be described below. 
     A dummy terminal  10  of the present invention is designed to be inserted into one of a plurality of connector-terminal sockets of a hub  101  originally intended to be connected with a large number of connector terminals of LAN cables so as to interconnect a plurality of computers serving as communication terminal units, and engaged with the connector-terminal socket in such a manner that the engaged state is selectively locked or unlocked. 
       FIG. 5  is a perspective view showing the plurality of connector-terminal sockets  104  of the hub  101  for insertingly receiving the dummy terminal  10  of the present invention.  FIG. 6  shows a state before the dummy terminal  10  according to the first embodiment is inserted into one of the connector-terminal sockets  104  of the hub  101 , and  FIG. 7  shows a state after the dummy terminal  10  according to the first embodiment is inserted into the connector-terminal socket  104 , and locked in its engaged state. 
     As shown in  FIG. 5 , each of the plurality of connector-terminal sockets  104  has a first groove  104 A formed to extend rearward from an upper region of an opening thereof and have a width which allows the wide flexible portion  14 B of the engagement member  14  to be inserted therealong, and a second groove  104 B formed to extend from the opening along an inner top surface thereof and have a width which precludes the wide flexible portion  14 B of the engagement member  14  from being inserted thereinto and allows only the narrow engagement release portion  14 D to be inserted therealong. The connector-terminal latching portion is defined by a step between the first groove  104 A and the second groove  104 B. Specifically, the first groove  104 A is formed to have a relatively short length in an insertion direction of the dummy terminal  10 . Thus, when the dummy terminal  10  is fully inserted into the connector-terminal socket, the engagement portion  14 C falls in the connector-terminal latching portion defined by the step vertically extending between the first groove  104 A and the second groove  104 B, according to an elastic force of the flexible portion  14 B, so that the dummy terminal body  12  is engaged with the connector-terminal latching portion. 
     With reference to  FIGS. 6 and 7 , the operation for inserting the dummy terminal  10  into the connector-terminal socket  104  of the hub  101 , and locking in the engaged state will be described in more detail below. In  FIG. 6 , the set screw  30  is loosened. Thus, the thin plate member  13  is not tightly mounted on the dummy terminal body  12 , and thereby the engagement member  14  is not in a restrained state. In this state, when the dummy terminal  10  is inserted into the connector-terminal socket  104  from the side of the anchor portion  14 A of the engagement member  14 , the flexible portion  14 B of the engagement member  14  is inserted along the first groove  104 A while elastically deforming. 
     Along with the insertion of the dummy terminal  10 , the flexible portion  14 B of the engagement member  14  will be gradually pushed down by an inner top surface of the first groove  104 A while passing through the first groove  104 A. Then, just after reaching the aforementioned connector-terminal latching portion, the engagement portion  14 C falls and enters in the narrow second groove  104 B according to the elastic force of the flexible portion  14 B, and engaged with the connector-terminal latching portion. Thus, the width-directional steps between the flexible portion  14 B and the engagement release portion  14 D are engaged with the vertical step between the first groove  104 A and the second groove  104 B, to allow the dummy terminal  10  inserted into the connector-terminal socket  104  to be placed in an engaged state. 
     After the dummy terminal  10  inserted into the connector-terminal socket  104  is placed in the engaged state, the set screw  30  is driven into the screw hole or tightened. As mentioned above, the thin plate member  13  is formed with the loose hole  13 C for allowing the set screw  30  to loosely penetrate therethrough. Through the operation of tightening the set screw  30 , the anchor portion  13 A of the thin plate member  13  is fixedly mounted on the front wall  12 D of the dummy terminal body  12 . The fixed anchor portion  13 A allows the restraint portion  13 B to restrain movement of the engagement release portion  14 D of the engagement member  14 . Thus, shown in  FIG. 7 , the dummy terminal  10  inserted into the connector-terminal socket  104  is maintained (or locked) in the engaged state. In this way, the dummy terminal of the present invention can be inserted into a connector-terminal socket which is not connected with any connector terminal but banned from being used, and placed in a latched state in advance, so as to prevent an improper connector terminal from being erroneously inserted thereinto. 
     In an operation for pulling out the dummy terminal  10  inserted and placed in the latched state, the set screw  30  is firstly loosened to release the fixed state of the anchor portion  13 A of the thin plate member  13  and allow the engagement release portion  14 D restrained in movement by the restraint portion  13 B to be movable. Then, the engagement release portion  14 D is pressed down against its own elastic force. Through this downward pressing, the width-directional steps between the flexible portion  14 B and the engagement release portion  14 D are disengaged from the vertical step between the first groove  104 A and the second groove  104 B, to allow the dummy terminal  10  to be pulled out of the connector-terminal socket  104 . 
     While the type of the set screw  30  is not specified in the first embodiment, a normal screw may be used or a special screw as shown in  FIG. 8  may be used. 
     Even if the dummy terminal  10  is simply inserted into a connector-terminal socket, an effect of preventing an accidental trouble otherwise caused by erroneously inserting an improper connector terminal can be obtained. However, if the set screw  30  is a normal type, it can be readily loosened. Thus, the dummy terminal  10  using a normal screw is not effective against a trouble caused by erroneously pulling out the dummy terminal  10  from a connector-terminal socket and inserting an improper connector terminal into the connector-terminal socket. 
       FIGS. 8A to 8C  show some examples of a special screw usable as the set screw  30 . The set screw  30  comprises a screw head  30 A and a threaded shank  30 B.  FIGS. 8A ,  8 B and  8 C show respective examples of an ultrathin flathead screw, a countersunk tamper-proof screw and a round tamper-proof screw. Each of these set screws has a screw head  30 A for use in tightening and loosening the screw. The screw head  30 A is formed with a special 3-dimensional dent, and can be driven using a single-purpose tool to detach the set screw  30 . 
     The special screws as shown in  FIGS. 8A to 8C  used as the set screw  30  make it possible to provide self-distinctiveness to the dummy terminals of the present invention, so as to allow each network administrator to distinguish between a proper or authorized connector-terminal socket and an improper or unauthorized connector-terminal socket. Specifically, the special screws as shown in  FIGS. 8A to 8C  are required to use single-purpose tools for tightening/loosening them. 
     Thus, for example, the special screw illustrated in  FIG. 8A  is used as the set screw  30  of the dummy terminal for a specific connector-terminal socket to be used by a specific network administrator, and a single-purpose tool necessary for tightening/loosening the special screw illustrated in  FIG. 8A  is managed such that it can be used only by the specific network administrator. This makes it possible to allow only by the specific network administrator to use the specific connector-terminal socket. Thus, a special screw used as the set screw  30  can prevent occurrence of a trouble caused by erroneously pulling out the dummy terminal  10  from a connector-terminal socket. 
     &lt;Example of Modification&gt; 
     While the first embodiment has been described such that the set screw  30  is loosened during the operation for inserting the dummy terminal  10  into the connector-terminal socket  104 , the present invention is not limited to this manner. For example, the set screw  30  is firstly tightened to fixedly mount the anchor portion  13 A on the front wall  12 D so as to restrain movement of the engagement release portion  14 D of the engagement member  14 , and then the dummy terminal  10  set as shown in  FIG. 7  may be inserted into the connector-terminal socket  104 . This operation can be performed, because, even if the engagement member  14  is in the restrained state, the flexible portion  14 B of the engagement member  14  is pushed rearward while elastically deforming, along with insertion of the dummy connector  10  into the connector-terminal socket  104 , and finally reaches the connector-terminal latching portion. In this case, the dummy terminal  10  having the set screw  30  in the tightened state can be inserted into the connector-terminal socket  104 . Thus, a plurality of the dummy terminals pre-set as above can be successively inserted one-by-one into a plurality of connector-terminal sockets banned from being used, so as to effectively prevent erroneous connection of connector terminals. 
     Second Embodiment 
     With reference to  FIGS. 9 to 12 , a second embodiment of the present invention will be described below.  FIG. 9  is a perspective view showing a dummy terminal  10  according the second embodiment.  FIGS. 10 ,  11  and  12  are, respectively, a top plan view, a side view and a front view showing the dummy terminal  10  according the second embodiment. 
     The dummy terminal  10  comprises an approximately rectangular parallelepiped-shaped dummy terminal body  12 , a thin plate member  13 , an engagement member  14  and a set screw  30 . The dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of a target connector-terminal socket. The thin plate member  13  is swingably fixed to or formed with a front lower edge of the dummy terminal body  12 , and the engagement member  14  is fixedly mounted on a rear upper edge of the dummy terminal body  12 . The dummy terminal body  12  has a screw hole  12 F for threadingly receiving the set screw  30 . The screw hole  12 F extends from a front surface of the dummy terminal body  12  in a direction perpendicular to the front surface. 
     The thin plate  13  is generally composed of a pivotal portion  12 G fixed to or formed with the front lower edge of the dummy terminal body  12 , an anchor portion  13 A adapted to be swung about the pivotal portion  12 G and brought into contact with the front surface of the dummy terminal body  12 , and a restraint portion  13 B for placing an engaged state of the engagement member  14  under restraint. A cutout  13 D for allowing the set screw to penetrate therethrough is formed in an approximately laterally central region of the anchor portion  13 A. The cutout  13 D extends parallel to a direction from the pivotal portion  12 G toward the restraint portion  13 B. When the set screw  30  is loosened but not detached, the cutout  13 D allows the thin plate member  13  to be swung at an angle corresponding to the level of loosening of the set screw  30 . 
     The engagement member  14  is mounted on the rear upper edge of the dummy terminal body  12 . The engagement member  14  has an anchor portion  14 A fixedly mounted on the dummy terminal body  12 , a deformable or flexible portion  14 B, an engagement portion  14 C and an engagement release portion  14 D. In the engagement member  14 , the flexible portion  14 B is formed to have a relatively large width, and the engagement release portion  14 D continuous with the flexible portion  14 B is formed to have a width less than that of the flexible portion  14 B. That is, the engagement member  14  is formed with a pair of steps extending in a width direction at approximately the longitudinal center thereof, and the steps serves as the engagement portion  14 C adapted to be engaged with the connector-terminal latching portion formed in the connector-terminal socket. 
     In an operation for inserting the dummy terminal  10  according to the second embodiment into a connector-terminal socket of a hub  101 , and locking in an engaged state of the dummy terminal  10 , the set screw  30  illustrated in  FIG. 9  is firstly loosened to prevent the restraint portion from restraining movement of the engagement release portion  14 D. In this state, the dummy terminal  10  is inserted into the connector-terminal socket. Along with the insertion of the dummy terminal  10  into the connector-terminal socket, the flexible portion  14 B of the engagement member  14  will be pushed rearward while elastically deforming, and the engagement portion  14 C is engaged with a connector-terminal latching portion formed in the connector-terminal socket. Then, when the set screw  30  is tightened after the dummy terminal  10  is inserted into the connector-terminal socket  104  and placed in the engaged state, the anchor portion  13 A of the thin plate member  13  is brought in contact with the front surface of the dummy terminal body  12  and fixedly mounted thereon. The fixed anchor portion  13 A allows the restraint portion  13 B to restrain movement of the engagement release portion  14 D of the engagement member  14 . Thus, the dummy terminal  10  inserted into the connector-terminal socket  104  is maintained (or locked) in the engaged state. In this way, the dummy terminal of the present invention can be inserted into a connector-terminal socket which is not connected with any connector terminal but banned from being used, and placed in a latched state in advance, so as to prevent an improper connector terminal from being erroneously inserted thereinto. 
     In an operation for pulling out the dummy terminal  10  inserted and placed in the latched state, the set screw  30  is firstly loosened to release the fixed state of the anchor portion  13 A of the thin plate member  13  and allow the engagement release portion  14 D restrained in movement by the restraint portion  13 B to be movable. Then, the engagement release portion  14 D is pressed down against its own elastic force. Through this downward pressing, the dummy terminal  10  can be released from the engaged state, and pulled out of the connector-terminal socket  104 . 
     Each of the dummy terminal body  12 , the thin plate member  13  and the engagement member  14  is primarily made of a synthetic resin having insulating performance and elasticity in addition to excellent formability and cost performance, such as ABS (acrylonitrile-butadiene-styrene) resin or PC (polycarbonate) resin. 
     Third Embodiment 
     With reference to  FIGS. 13A to 14B , a third embodiment of the present invention will be described. 
       FIG. 13A  is a perspective view showing a dummy terminal  10  according the third embodiment, and  FIG. 13B  is a partially sectional view showing a state after the dummy terminal  10  is inserted into a connector-terminal socket.  FIGS. 14A and 14B  are, respectively, a side view and a top plan view showing a dummy terminal body  12  in the dummy terminal  10  according the third embodiment. 
     The dummy terminal  10  according the third embodiment comprises a dummy terminal body  12 , and a set screw  30 . The dummy terminal body  12  has an approximately rectangular parallelepiped-shaped base  16  adapted to be inserted into a connector-terminal socket, a standing member  17  formed at one end of the base  16  on the opposite side of the other end to be firstly inserted into a connector-terminal socket, and an engagement member  14  which extends approximate Ely parallel to the base, and has a distal end formed as an engagement portion  14 A adapted to be engaged with a connecter-terminal latching portion of a target connector-terminal socket, and a proximal end connected to the standing member  17 . This dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of the connector-terminal socket. The base  16 , the standing member  17 , the engagement member  14  are integrally formed in a single piece. 
     The base  16  is formed with a screw hole  16  threadingly engageable with the set screw  30 , and the engagement member  14  is formed with a loose hole  30  for allowing the set screw  30  to loosely penetrate therethrough. The engagement member  14  is formed to allow a distance between the distal end and the base  16  to become greater than a distance between a distance between the proximal end and the base  16 . As described in connection with the first and second embodiments, the dummy terminal body  12  having the base  16 , the engagement member  14  and the standing member  17  is primarily made of a synthetic resin having insulating performance and elasticity in addition to excellent formability and cost performance. 
     An operation for inserting the dummy terminal  10  according to the third embodiment into a connector-terminal socket of a hub  101  and locking in a latched state of the dummy terminal  10  will be described below. 
     As mentioned above, the dummy terminal  10  of the present invention is designed to be inserted into one of a plurality of connector-terminal sockets of a hub  101  originally intended to be connected with a large number of connector terminals of LAN cables so as to interconnect a plurality of computers serving as communication terminal units, and engaged with the connector-terminal socket in such a manner that the engaged state is selectively locked or unlocked. 
     The hub  101  illustrated in  FIGS. 13B  has the same structure as that illustrated in  FIG. 5 . Specifically, each of the plurality of connector-terminal sockets  104  has the first groove  104 A and the second groove  104 B, and the connector-terminal latching portion is defined by the step between the first groove  104 A and the second groove  104 B. When the dummy terminal  10  is inserted into the connector-terminal socket, the engagement member  14  is inserted along the first groove  104 A while elastically deforming, and the engagement portion is engaged with the connector-terminal latching portion in a latched state. The dummy terminal  10  according to the third embodiment has no engagement release member, and thereby the latched state is hardly released. Thus, the dummy terminal  10  according to the third embodiment can be simply inserted into a connector-terminal socket which is not connected with any connector terminal but banned from being used, so as to prevent an improper connector terminal from being erroneously inserted thereinto. 
     In an operation for pulling out the dummy terminal  10  according to the third embodiment, the set screw  30  is loosened to allow the engagement member  14  to be deformed toward the base  16  against elasticity of the engagement member  14  and the standing member  17 , so as to release the engaged and latched state between the engagement portion  14 A and the connecter-terminal latching portion. 
     &lt;Example of Modification&gt; 
     While the first embodiment has been described such that the screw hole  16 A threadingly engageable with the set screw  30  is formed in the base  16 , the present invention is not limited to such a structure, but the engagement member  14  may be formed with a screw hole. When the screw hole  16 A is formed in the engagement member  14 , the engagement member  14  is formed to allow a distance between the distal end and the base  16  to become approximately equal to a distance between a distance between the proximal end and the base  16 . In this modification, when the set screw  30  is tightened, the engagement member  14  is deformed upward or in a direction getting away from the base  16  to allow an engaged state between the engagement portion  14 A and the connector-terminal latching portion to be placed in a latched state. This latched state may be released by loosening the set screw  30 . In this structure, there is no need for forming a loose hole in the base  16 . 
     Fourth Embodiment 
     With reference to  FIGS. 15A to 16B , a fourth embodiment of the present invention will be described.  FIG. 15A  is a perspective view showing a dummy terminal  10  according the fourth embodiment, and  FIG. 15B  is a partially sectional view showing a state after the dummy terminal  10  is inserted into a connector-terminal socket.  FIGS. 16A and 16B  are, respectively, a side view and a top plan view showing a dummy terminal body  12  in the dummy terminal  10  according the fourth embodiment. 
     The dummy terminal  10  according the fourth embodiment comprises a dummy terminal body  12 , and a set screw  30 . The dummy terminal body  12  has a base  16  adapted to be inserted into a terminal-connector socket, a standing member  17  formed at one end of the base  16  on the opposite side of the other end to be firstly inserted into the connector-terminal socket, an engagement member  14  which extends approximately parallel to the base  16  and has a distal end formed as an engagement portion  14 A adapted to be engaged with a connecter-terminal latching portion of a target connector-terminal socket, and a proximal end connected to the standing member  17 , and a grip member  19  which has a screw-hole defining portion  18  integrated with the base  16  and formed with a screw hole  18 A for the set screw  30 , and a grip portion  19  for allowing an operator or user to grip it in an operation of inserting and detaching the dummy terminal body  12  into/from the connecter-terminal socket. This dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of the connector-terminal socket. The base  16 , the standing member  17 , the engagement member  14  are integrally formed in a single piece. 
     The engagement member  14  is formed to allow a distance between the distal end and the base  16  to become greater than a distance between a distance between the proximal end and the base  16 . The screw hole  18 A in the screw-hole defining portion  18  is formed to have a given angle with an insertion direction in which the base  16  is inserted into the connector-terminal socket, so as to allow a top of the set screw  30  to be brought into contact with the engagement member  14  when the set screw  30  is threadingly driven into the screw hole  18 A or tightened. As described in connection with the first to third embodiments, the dummy terminal body  12  having the base  16 , the engagement member  14 , the standing member  17  and grip member  19  is primarily made of a synthetic resin having insulating performance and elasticity in addition to excellent formability and cost performance. 
     An operation for inserting the dummy terminal  10  according to the fourth embodiment into a connector-terminal socket of a hub  101  and locking in a latched state of the dummy terminal  10  will be described below. 
     As mentioned above, the dummy terminal  10  of the present invention is designed to be inserted into one of a plurality of connector-terminal sockets of a hub  101  originally intended to be connected with a large number of connector terminals of LAN cables so as to interconnect a plurality of computers serving as communication terminal units, and engaged with the connector-terminal socket in such a manner that the engaged state is selectively locked or unlocked. 
     The hub  101  illustrated in  FIG. 14B  has the same structure as that illustrated in  FIG. 5 . Specifically, each of the plurality of connector-terminal sockets  104  has the first groove  104 A and the second groove  104 B, and the connector-terminal latching portion is defined by the step between the first groove  104 A and the second groove  104 B. When the dummy terminal  10  according to the fourth embodiment is inserted into the connector-terminal socket, and the set screw  30  is tightened, the engagement member  14  is deformed by the top of the set screw  30  toward the connecter-terminal latching portion against elasticity of the standing member  17 , to allow the engagement portion  14 A to be fixedly engaged with the connecter-terminal latching portion and placed in a latched state. This latched state can prevent an improper connector terminal from being erroneously inserted into the connecter-terminal socket. 
     In the dummy terminal  10  according to the fourth embodiment, when the set screw  30  is loosened, the engagement portion  14 A is returned to it original position approximately parallel to the base  16  according to elasticity of the engagement member  14  and the standing member  17 , so as to release the engaged and latched state between the engagement portion  14 A and the connecter-terminal latching portion. After the release of the latched state, the dummy terminal  10  can be pulled out of the connector-terminal socket. 
     Fifth Embodiment 
     With reference to  FIGS. 17 to 20 , a fifth embodiment of the present invention will specifically be described. 
     A dummy terminal  10  according to the fifth embodiment has means for discriminating between a plurality of connector-terminal sockets.  FIG. 17  is an explanatory perspective view showing one example of means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the first embodiment, and  FIG. 18  is an explanatory perspective view showing another example of the means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the second embodiment.  FIG. 19  is an explanatory perspective view showing another example of the means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the third embodiment, and  FIG. 20  is an explanatory perspective view showing another example of the means for discriminating between a plurality of connector-terminal sockets, based on the dummy terminal  10  according to the fourth embodiment. 
     With reference to  FIG. 17 , a dummy terminal having means for discriminating between a plurality of connecter-terminal sockets will be specifically described in connection with one example based on the first embodiment. In  FIG. 17 , the same component or element as that of the first embodiment is defined by the same reference numeral. This dummy terminal  10  comprises a dummy terminal body  12 , a thin plate member  13 , an engagement member  14  and a set screw  30 . The dummy terminal body  12  is generally composed of a grooved frame defined by opposite side walls  12 A,  12 B and top wall  12 C, and a front wall  12 D formed at a front end of the grooved frame. This dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of a target connector-terminal socket. The thin plate member  13  is generally composed of an anchor portion  13 A to be mounted on the front wall  12 D, and a restraint portion  13 B for placing an engaged state of the engagement member  14  under restraint. The engagement member  14  is mounted on the rear end of the grooved frame of the dummy terminal body  12 . The engagement member  14  has an anchor portion  14 A fixedly mounted on the dummy terminal body  12 , a deformable or flexible portion  14 B, an engagement portion  14 C and an engagement release portion  14 D. 
     In the dummy terminal  10 , a color sticker  111  serving as the discrimination means is attached on the anchor portion  13 A. The dummy terminal  10  having the color sticker  111  thereon makes it possible to discriminate between a plurality of connector-terminal sockets each having the dummy terminal  10  inserted therein, on a type-by-type basis, for example, between one or more authorized connector-terminal sockets and one or more unauthorized connector-terminal sockets on an administrator-by-administrator basis. 
     With reference to  FIG. 18 , a dummy terminal having means for discriminating between a plurality of connecter-terminal sockets will be specifically described in connection with another example based on the second embodiment. In  FIG. 18 , the same component or element as that of the second embodiment is defined by the same reference numeral. This dummy terminal  10  comprises an approximately rectangular parallelepiped-shaped dummy terminal body  12 , a thin plate member  13 , an engagement member  14  and a set screw  30 . The dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of a target connector-terminal socket. The thin plate member  13  is swingably fixed to or formed with a front lower edge of the dummy terminal body  12 , and the engagement member  14  is fixedly mounted on a rear upper edge of the dummy terminal body  12 . The dummy terminal body  12  has a screw hole  12 F for threadingly receiving the set screw  30 . The screw hole  12 F extends from a front surface of the dummy terminal body  12  in a direction perpendicular to the front surface. The thin plate  13  is generally composed of a pivotal portion  12 G fixed to or formed with the front lower edge of the dummy terminal body  12 , an anchor portion  13 A adapted to be swung about the pivotal portion  12 G and brought into contact with the front surface of the dummy terminal body  12 , and a restraint portion  13 B for placing an engaged state of the engagement member  14  under restraint. A cutout  13 D for allowing the set screw to penetrate therethrough is formed in an approximately laterally central region of the anchor portion  13 A. The cutout  13 D extends parallel to a direction from the pivotal portion  12 G toward the restraint portion  13 B. When the set screw  30  is loosened but not detached, the cutout  13 D allows the thin plate member  13  to be swung at an angle corresponding to the level of loosening of the set screw  30 . 
     In this dummy terminal  10 , a color sticker  111  serving as the discrimination means is attached on the thin plate member  13 . The dummy terminal  10  having the color sticker  111  thereon makes it possible to discriminate between a plurality of connector-terminal sockets each having the dummy terminal  10  inserted therein, on a type-by-type basis, for example, between one or more authorized connector-terminal sockets and one or more unauthorized connector-terminal sockets on an administrator-by-administrator basis. 
     With reference to  FIG. 19 , the dummy terminal means for discriminating between a plurality of connecter-terminal sockets will be specifically described in connection with yet another example based on the third embodiment. In  FIG. 19 , the same component or element as that of the third embodiment is defined by the same reference numeral. 
     This dummy terminal  10  comprises a dummy terminal body  12 , and a set screw  30 . The dummy terminal body  12  has an approximately rectangular parallelepiped-shaped base  16  adapted to be inserted into a connector-terminal socket, a standing member  17  formed at one end of the base  16  on the opposite side of the other end to be firstly inserted into a connector-terminal socket, and an engagement member  14  which extends approximate Ely parallel to the base, and has a distal end formed as an engagement portion  14 A adapted to be engaged with a connecter-terminal latching portion of a target connector-terminal socket, and a proximal end connected to the standing member  17 . This dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of the connector-terminal socket. 
     In this dummy terminal  10 , a color sticker  111  serving as the discrimination means is attached on the standing member  17 . The dummy terminal  10  having the color sticker  111  thereon makes it possible to discriminate between a plurality of connector-terminal sockets each having the dummy terminal  10  inserted therein, on a type-by-type basis, for example, between one or more authorized connector-terminal sockets and one or more unauthorized connector-terminal sockets on an administrator-by-administrator basis. 
     With reference to  FIG. 20 , a dummy terminal having means for discriminating between a plurality of connecter-terminal sockets will be specifically described in connection with yet another example based on the fourth embodiment. In  FIG. 20 , the same component or element as that of the fourth embodiment is defined by the same reference numeral. 
     The dummy terminal  10  comprises a dummy terminal body  12 , and a set screw  30 . The dummy terminal body  12  has a base  16  adapted to be inserted into a terminal-connector socket, a standing member  17  formed at one end of the base  16  on the opposite side of the other end to be firstly inserted into the connector-terminal socket, an engagement member  14  which extends approximately parallel to the base  16  and has a distal end formed as an engagement portion  14 A adapted to be engaged with a connecter-terminal latching portion of a target connector-terminal socket, and a proximal end connected to the standing member  17 , and a grip member  19  which has a screw-hole defining portion  18  integrated with the base  16  and formed with a screw hole  18 A for the set screw  30 , and a grip portion  19  for allowing an operator or user to grip it in an operation of inserting and detaching the dummy terminal body  12  into/from the connecter-terminal socket. This dummy terminal body  12  is formed to have approximately same size as that of an insertion portion of the connector-terminal socket. 
     In this dummy terminal  10 , a color sticker  111  serving as the discrimination means is attached on the grip member  19 . The dummy terminal  10  having the color sticker  111  thereon makes it possible to discriminate between a plurality of connector-terminal sockets each having the dummy terminal  10  inserted therein, on a type-by-type basis, for example, between one or more authorized connector-terminal sockets and one or more unauthorized connector-terminal sockets on an administrator-by-administrator basis. 
     &lt;Example of Modification&gt; 
     In the fifth embodiment, a position on which the color sticker attached may be appropriately selected in consideration of convenience for management and distinctiveness. In addition to a color sticker, the discrimination means may include coloring a dummy terminal  10 . In this case, the dummy terminal  10  may be entirely colored, or may be partially colored only in a recognizable area. Alternatively, a mark, such as character and/or symbol, may be used as the discrimination means. 
     Further, plural kinds of set screws as shown in  FIGS. 8A to 8C  may be used in each of the dummy terminals, as the discrimination means. Particularly, when the special screws are used as the discrimination means, the use of each dummy terminal can be managed based on a special tool only owned by an authorized administrator. In cases where one communication network is managed by a plurality of administrators, the discrimination based on the special screws is an effective method for managing connector-terminal sockets on an administrator-by-administrator basis. It is understood that the discrimination based on plural kinds of set screws  30  may be used in combination with the color sticker in the fifth embodiment or other discrimination means. 
     INDUSTRIAL APPLICABILITY 
     The present invention can provide a dummy terminal capable of being inserted in a lockable manner into a connector-terminal socket, instead of a cable connector terminal, so as to prevent a cable connector terminal from being erroneously inserted into an improper or unauthorized connector-terminal socket which has no cable connector terminal connected thereto. 
     Further, the present invention can provide a dummy terminal capable of being inserted in a lockable manner into a connector-terminal socket, instead of a cable connector terminal, while allowing each network administrator to distinguish whether or not the connector-terminal socket is an authorized connector-terminal socket. 
     In addition to a LAN-cable connector-terminal as described in the above embodiments, the dummy connector of the present invention may be used instead of any other connector terminal having an engagement function, such as a modular terminal for telephone lines.