Patent Publication Number: US-8968013-B2

Title: Modular jack

Description:
This application is based on and claims the benefit of priority from Japanese Patent Application No. 2012-203481, filed on 14 Sep. 2012, the content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a modular jack. More specifically, the present invention relates to a structure of a modular jack to which a modular plug for a LAN (Local Area Network) is connected, the modular jack being compactly installed in an electronic device such as a notebook PC, enabling a height reduction in the electronic device. 
     2. Related Art 
     An electronic device such as a notebook PC is provided with a modular jack for LAN connections on a side face or a rear face thereof. As a modular plug for a LAN, an RJ45 plug with 8 pin contacts is widely used. Many electronic devices such as notebook PCs therefore employ an RJ45 jack as a modular jack for a LAN. 
     Recently, the modular jack as described above is mounted on a printed circuit board and installed in an electronic device such as a notebook PC. However, the modular jack according to conventional techniques is has a large thickness and has a disadvantage in that it increases the size of the notebook PC in which the modular jack is installed. 
     In order to solve the abovementioned disadvantage, a modular jack is disclosed in Japanese Unexamined Patent Application Publication No. 2000-92159, for example, (hereinafter referred to as Patent Document 1). Patent Document 1 discloses a modular jack that can be electrically connected to a plug inserted into an insertion opening provided on a first end thereof, the modular jack comprising: a cuboidal housing with the insertion opening for the plug and a plug receiving chamber; and a cover housing. The cover housing can extend a side face of the housing adjacent to the insertion opening and extend the insertion opening, allowing insertion of the plug into the plug receiving chamber. 
     In other words, in the modular jack according to Patent Document 1, in a state before insertion of the plug into the jack, the side face of the cover housing overlaps the side face of the housing to a predetermined extent, and the height (h) of the jack is smaller than the height (H) of the jack after the insertion of the plug. 
     However, the modular jack according to Patent Document 1 includes a mechanism to pivotally support both side faces adjacent to a wall of the plug receiving chamber on the opposite side to the insertion opening such that the cover housing is rotatable, as a structure for extending the side face of the housing adjacent to the insertion opening and extending the insertion opening for the plug. Due to the thickness of the plug receiving chamber and the housing composing the plug receiving chamber with such a mechanism, the height (h) of the modular jack according to Patent Document 1 becomes greater than a prescribed height (Hp) of a plug corresponding to the RJ45 plug. 
     There is a demand for modular jacks for a LAN, such as the RJ45 jack, to be of lower height. This is because configuring the height of a modular jack to be less than the prescribed height (Hp) of the RJ45 plug enables reduction in the height of an electronic device such as a notebook PC in which the modular jack is installed. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the abovementioned problem and aims at providing a modular jack of a reduced height to be installed in an electronic device such as a notebook PC, allowing reduction in size of the electronic device. 
     An embodiment of the present invention is 
     a modular jack to which a modular plug with a latching tab is electrically connected, the modular jack comprising a socket connector including: 
     a base connector provided inside a casing with an opening on a side face, an upper housing that can interlock with the latching tab, and a parallel crank mechanism that can switch the upper housing between a lowered state and a raised state, the socket connector being slidably connected to the base connector; 
     wherein in the lowered state of the upper housing, a front face of the upper housing shuts the opening and the socket connector can be housed inside the casing, and in the raised state in which the upper housing is pulled out from the opening and raised outside of the casing, the modular plug can interlock with the upper housing via the latching tab and electrically connect to the base connector. 
     The modular jack according to the embodiment of the present invention further comprises a fixing member for installing the base connector to a printed circuit board inside the casing. 
     In the modular jack according to the embodiment of the present invention, the fixing member is a metallic tab provided on a side wall of the base connector. 
     In the modular jack according to the embodiment of the present invention, the side wall of the base connector with the metallic tab is held along an edge portion of the printed circuit board. 
     In a more detailed first embodiment of the modular jack according to the embodiment of the present invention, the base connector includes: 
     a plate-like base housing provided with a first contact array base positioned on a rear side with respect to the opening of the casing, and a pair of opposing guide arms extending from the first contact array base toward the opening; and 
     a first contact formed as a plurality of flat springs, an extremity portion thereof protruding from the first contact array base between the pair of guide arms, a middle portion thereof being fixed to the first contact array base, and a base end portion thereof protruding to a side opposite to the guide arms and being joined to the printed circuit board; and 
     the socket connector includes: 
     a plate-like socket housing provided with a second contact array base that is positioned at a base end portion of the socket connector and engages with the first contact array base so as to overlap the first contact array base, and a base portion that is disposed at an extremity portion of the socket connector, both side faces thereof being guided to an inner wall of the pair of guide arms, and to which a first end of each of a plurality of link plates constituting the parallel crank mechanism is rotatably connected; and 
     a second contact formed as a plurality of flat springs, being arrayed on the second contact array base and being in slidable contact with the extremity portion of the first contact, and having a bent portion in an extremity portion thereof that can connect to a mating-side contact. 
     In a more detailed second embodiment of the modular jack according to the embodiment of the present invention, the base connector includes: 
     a rectangular plate-like base housing provided with a substantially rectangular concave portion surrounded by a pair of opposing first side walls and a second side wall which connects first ends of the first side walls, and a first contact array base formed on a bottom wall of the concave portion; and 
     a first contact formed as a plurality of flat springs, an extremity portion thereof protruding from the bottom wall of the concave portion, a middle portion thereof being fixed to the first contact array base, and a base end portion thereof protruding to the outside of the second side wall of the base housing and being joined to the printed circuit board, and the socket connector includes: 
     a plate-like socket housing provided with a second contact array base that is positioned at a central portion of the socket connector and faces the first contact array base so as to overlap the first contact array base, and a connection portion to which a first end of each of a plurality of link plates constituting the parallel crank mechanism is rotatably connected, the socket housing being disposed to be housed inside the concave portion of the base housing while both side faces thereof are guided by inner walls of the first side walls; and 
     a second contact formed as a plurality of flat springs, being arrayed on the second contact array base and being in contact with the extremity portion of the first contact, and having a bent portion in an extremity portion thereof that can connect to a mating-side contact. 
     In the more detailed first or second embodiment of the modular jack according to the embodiment of the present invention, the plurality of link plates includes two pairs of link plates, a first pair of the two pairs of link plates having guide pawls that guide a pair of side faces of the plug housing. 
     In the more detailed first embodiment of the modular jack according to the embodiment of the present invention, the pair of guide arms have opposing grooves that extend from the first contact array base to an extremity of each of the guide arms; 
     the socket housing has a pair of projecting portions that protrude in opposite directions and are guided by the grooves, in both end portions of the base portion; and 
     the grooves have first stop projections that engage with the projecting portions to maintain the socket housing in a stored state with respect to the base housing, and second stop projections that engage with the projecting portions to maintain the socket housing in a pulled-out state with respect to the base housing, the first stop projections and the second stop projections protruding from a bottom face of the grooves. 
     In the more detailed second embodiment of the modular jack according to the embodiment of the present invention, the pair of first side walls have opposing grooves that extend from the second side wall to extremities of the first side walls; 
     the socket housing has a pair of projecting portions that protrude in opposite directions and are guided by the grooves, in both side portions of the socket housing; and 
     the grooves have first stop projections that engage with the projecting portions to maintain the socket housing in a stored state with respect to the base housing, and second stop projections that engage with the projecting portions to maintain the socket housing in a pulled-out state with respect to the base housing, the first stop projections and the second stop projections protruding from a bottom face of the grooves. 
     According to the modular jack of the present invention, in a state in which the upper housing is lowered toward the front side of the socket housing, the socket connector can be housed inside the casing, and both faces of the upper housing, the socket housing, and the base housing are formed in a flat plate-like shape. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a diagram illustrating a state in which a modular jack of a first embodiment is housed inside a casing; 
         FIG. 1B  is a diagram illustrating a state in which a socket connector provided in the modular jack of the first embodiment is pulled out from the casing; 
         FIG. 1C  is a diagram illustrating a state in which an upper housing provided in the socket connector is raised from the state shown in  FIG. 1B ; 
         FIG. 1D  is a diagram illustrating a state in which a modular plug is connected to the modular jack in a state shown in  FIG. 1C ; 
         FIG. 2A  is a diagram illustrating a state in which the modular jack of the first embodiment is stored inside the casing, showing the casing with imaginary lines; 
         FIG. 2B  is a diagram illustrating a state in which the socket connector provided in the modular jack of the first embodiment is pulled out from the casing, showing the casing with imaginary lines; 
         FIG. 2C  is a diagram illustrating a state in which an upper housing provided in the socket connector is raised from the state shown in  FIG. 2B , showing the casing with imaginary lines; 
         FIG. 2D  is a diagram illustrating a state in which the modular plug is connected to the modular jack in a state shown in  FIG. 2C , showing the casing with imaginary lines; 
         FIG. 3  is a perspective view illustrating a configuration of the modular jack of the first embodiment, disposed to face a printed circuit board inside the casing; 
         FIG. 4  is a perspective view illustrating a configuration of the modular jack of the first embodiment in a state in which a base housing and the socket connector are disposed to face each other; 
         FIG. 5  is an exploded perspective view illustrating a configuration of the modular jack of the first embodiment; 
         FIG. 6A  is a front view of the modular plug; 
         FIG. 6B  is a plan view of the modular plug; 
         FIG. 6C  is a right side view of the modular plug; 
         FIG. 6D  is a left side view of the modular plug; 
         FIG. 6E  is a rear view of the modular plug; 
         FIG. 6F  is a bottom view of the modular plug; 
         FIG. 6G  is a perspective view of the modular plug; 
         FIG. 7  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the socket connector is housed inside the casing; 
         FIG. 8  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the socket connector is pulled out from the casing; 
         FIG. 9  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the upper housing provided in the socket connector is raised; 
         FIG. 10  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the modular plug is connected to the modular jack; 
         FIG. 11  is a front view illustrating a configuration of the modular jack of the first embodiment in a state of  FIG. 10 , in a state in which the upper housing provided in the socket connector is raised; 
         FIG. 12  is a perspective view illustrating a configuration of the modular jack of the first embodiment in a state in which the socket connector is pulled out from the casing; 
         FIG. 13  is a perspective view illustrating a configuration of the modular jack of the first embodiment in a state in which the modular plug is connected to the modular jack; 
         FIG. 14A  is a cross-sectional view taken along a line A-A of  FIG. 7  illustrating a configuration of the modular jack of the first embodiment; 
         FIG. 14B  is an enlarged view of a main portion of  FIG. 14A ; 
         FIG. 15A  is a cross-sectional view taken along a line A-A of  FIG. 8  illustrating a configuration of the modular jack of the first embodiment; 
         FIG. 15B  is an enlarged view of a main portion of  FIG. 15A ; 
         FIG. 16  is a cross-sectional view taken along a line A-A of  FIG. 9  illustrating a configuration of the modular jack of the first embodiment; 
         FIG. 17  is a cross-sectional view taken along a line A-A of  FIG. 10  illustrating a configuration of the modular jack of the first embodiment; 
         FIG. 18A  is a diagram illustrating a state in which a modular jack of a second embodiment is housed inside a casing; 
         FIG. 18B  is a diagram illustrating a state in which a socket connector provided in the modular jack of the second embodiment is pulled out from the casing; 
         FIG. 18C  is a diagram illustrating a state in which the upper housing provided in the socket connector is raised from the state shown in  FIG. 18B ; 
         FIG. 18D  is a diagram illustrating a state in which the modular plug is connected to the modular jack in a state shown in  FIG. 180 ; 
         FIG. 19A  is a diagram illustrating a state in which the modular jack of the second embodiment is stored inside the casing, showing the casing with imaginary lines; 
         FIG. 19B  is a diagram illustrating a state in which the socket connector provided in the modular jack of the second embodiment is pulled out from the casing, showing the casing with imaginary lines; 
         FIG. 19C  is a diagram illustrating a state in which an upper housing provided in the socket connector is raised from the state shown in  FIG. 19B , showing the casing with imaginary lines; 
         FIG. 19D  is a diagram illustrating a state in which the modular plug is connected to the modular jack in a state shown in  FIG. 19C , showing the casing with imaginary lines; 
         FIG. 20  is a perspective view illustrating a configuration of the modular jack of the second embodiment, disposed to face a printed circuit board inside the casing; 
         FIG. 21  is a perspective view illustrating a configuration of the modular jack of the second embodiment in a state in which the base housing composing the modular jack and the socket connector are disposed to face each other; 
         FIG. 22  is an exploded perspective view illustrating a configuration of the modular jack of the second embodiment; 
         FIG. 23  is a vertical cross-sectional view illustrating a configuration of the modular jack of the second embodiment in a state in which the socket connector provided in the modular jack is housed inside the casing; 
         FIG. 24  is a vertical cross-sectional view illustrating a configuration of the modular jack of the second embodiment in a state in which the socket connector provided in the modular jack is pulled out from the casing; 
         FIG. 25  is a vertical cross-sectional view illustrating a configuration of the modular jack of the second embodiment in a state in which the upper housing provided in the socket connector is raised; 
         FIG. 26  is a vertical cross-sectional view illustrating a configuration of the modular jack of the second embodiment in a state in which the modular plug is connected to the modular jack; 
         FIG. 27A  is a cross-sectional view taken along a line A-A of  FIG. 23  illustrating a configuration of the modular jack of the second embodiment; 
         FIG. 27B  is an enlarged view of a main portion of  FIG. 27A ; 
         FIG. 28A  is a cross-sectional view taken along a line A-A of  FIG. 24  illustrating a configuration of the modular jack of the second embodiment; 
         FIG. 28B  is an enlarged view of a main portion of  FIG. 28A ; 
         FIG. 29  is a cross-sectional view taken along a line A-A of  FIG. 25  illustrating a configuration of the modular jack of the second embodiment; and 
         FIG. 30  is a cross-sectional view taken along a line A-A of  FIG. 26  illustrating a configuration of the modular jack of the second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, embodiments of the present invention are explained with reference to the drawings. 
     First Embodiment 
     Configuration of Modular Jack 
     First, a configuration of a modular jack according to a first embodiment of the present invention is described.  FIGS. 1A to 1D  are perspective views illustrating the configuration of the modular jack according to the first embodiment of the present invention.  FIG. 1A  is a diagram illustrating a state in which the modular jack of the first embodiment is housed inside a casing;  FIG. 1B  is a diagram illustrating a state in which a socket connector provided in the modular jack of the first embodiment is pulled out from the casing;  FIG. 1C  is a diagram illustrating a state in which an upper housing provided in the socket connector is raised from the state shown in  FIG. 1B ; and  FIG. 1D  is a diagram illustrating a state in which a modular plug is connected to the modular jack in a state shown in  FIG. 1C . 
       FIGS. 2A to 2D  are perspective views illustrating a configuration of the modular jack according to the first embodiment, showing the casing with imaginary lines.  FIG. 2A  is a diagram illustrating a state in which the modular jack of the first embodiment is housed inside the casing;  FIG. 2B  is a diagram illustrating a state in which the socket connector provided in the modular jack of the first embodiment is pulled out from the casing;  FIG. 2C  is a diagram illustrating a state in which an upper housing provided in the socket connector is raised from the state shown in  FIG. 2B ; and  FIG. 2D  is a diagram illustrating a state in which a modular plug is connected to the modular jack in a state shown in  FIG. 2C . 
       FIG. 3  is a perspective view illustrating a configuration of the modular jack of the first embodiment, disposed to face a printed circuit board inside the casing.  FIG. 4  is a perspective view illustrating a configuration of the modular jack of the first embodiment in a state in which the base housing composing the modular jack and the socket connector are disposed to face each other. 
       FIG. 5  is an exploded perspective view illustrating a configuration of the modular jack of the first embodiment.  FIGS. 6A to 6G  are diagrams illustrating a configuration of the modular plug:  FIG. 6A  is a front view;  FIG. 6B  is a plan view;  FIG. 6C  is a right side view;  FIG. 6D  is a left side view;  FIG. 6E  is a rear view;  FIG. 6F  is a bottom view; and  FIG. 6G  is a perspective view. 
     Overall Configuration 
     With reference to  FIGS. 1A to 5 , the modular jack (hereinafter simply referred to as “jack”)  10  of the first embodiment is provided with a base connector  1  and the socket connector  3 . The base connector  1  is mounted on the printed circuit board  1   p . The printed circuit board  1   p  is disposed inside the flat casing f 1  with a rectangular opening k 1  on a side face thereof. The flat casing f 1  is illustrated as a part of a casing of the electronic device. A side wall of the base connector  1  is held along an edge portion of the printed circuit board  1   p . More specifically, the side wall of the base connector  1  is held in a slot cutout s 1 , which faces the opening k 1 , on the printed circuit board  1   p . The slot cutout s 1  is composed of seven sides made on the printed circuit board  1   p , and has a front half portion on a front side and a rear half portion on a rear side with a smaller width than that of the front half portion. The socket connector  3  is slidably connected to the base connector  1 . The socket connector  3  is also provided with a parallel crank mechanism pcm at an extremity portion thereof. The parallel crank mechanism pcm allows switching of the upper housing  5 , which can engage with a latching tab  91   r , between a lowered state and a raised state. 
     Configuration of Modular Plug 
     With reference to  FIG. 1D  or  FIG. 6 , the modular plug (hereinafter simply referred to as “plug”)  91  is illustrated as an RJ45 plug. The plug  91  includes a plug housing  91   h , a key  91   k , and eight contacts  91   c  which are mating-side contacts. The plug housing  91   h  is configured to have a cuboidal outer shape and includes a first face  911 , a second face  912 , a first end face  91   a , and a pair of side faces  913 ,  913 , that are adjacent to these faces. The key  91   k  has a square prism shape and projects from the first end face  91   a  of the plug housing  91   h . In addition, a part of the key  91   k  extends to the second face  912  of the plug housing  91   h.    
     The plug housing  91   h  is provided with the latching tab  91   r . The latching tab  91   r  is disposed on the second face  912  of the plug housing  91   h , and a base end portion thereof connects with the key  91   k . The latching tab  91   r  has a pair of engaging pawls  91   n ,  91   n.    
     On an end portion of the first face  911  of the plug housing  91   h , eight comb-teeth grooves are formed. The plate-like contacts  91   c  are arranged in the grooves. Faces of the contacts  91   c  showing plate-thickness thereof are exposed and can contact a bent portion  32   a  provided in an extremity portion of a second contact  32  shown in  FIG. 5 . 
     Configuration of Modular Jack 
       FIG. 7  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the socket connector provided in the modular jack of the first embodiment is housed inside the casing. 
       FIG. 8  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the socket connector provided in the modular jack is pulled out from the casing.  FIG. 9  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the upper housing provided in the socket connector is raised. 
       FIG. 10  is a vertical cross-sectional view illustrating a configuration of the modular jack of the first embodiment in a state in which the modular plug is connected to the modular jack.  FIG. 11  is a front view illustrating a configuration of the modular jack of the first embodiment in a state of  FIG. 10 , in a state in which the upper housing provided in the socket connector is raised. 
       FIG. 12  is a perspective view illustrating a configuration of the modular jack of the first embodiment in a state in which the socket connector provided in the modular jack is pulled out from the casing.  FIG. 13  is a perspective view illustrating a configuration of the modular jack of the first embodiment in a state in which the modular plug is connected to the modular jack. 
     Configuration of Base Connector 
     With reference to  FIGS. 3 to 5 , the base connector  1  includes the plate-like base housing  1   h  and the first contact  11  that is in the form of eight flat springs. The base housing  1   h  is provided with a first contact array base  12  that has a substantially rectangular shape and a pair of opposing guide arms  13 ,  13 . The first contact array base  12  is disposed on the rear side of the slot cutout s 1  (see  FIGS. 2A to 2D ). The pair of guide arms  13 ,  13  extend from the first contact array base  12  toward the opening k 1  (see  FIG. 2A ). 
     Configuration of Base Housing 
     With reference to  FIGS. 3 to 5 , the base housing  1   h  is formed of a synthetic resin having insulation properties. On a bottom face of the first contact array base  12  of the base housing  1   h , a groove portion  12   d  having 8 grooves in comb-teeth form is provided (see  FIG. 4  or  FIG. 5 ). An intermediate portion  11   b  of the first contact  11  is pressed into the groove portion  12   d  (see  FIG. 5 ). 
     In addition, a pair of opposing rectangular grooves  121 ,  121  are formed on both sides of the groove portion  12   d  on the base housing  1   h . The pair of rectangular grooves  121 ,  121  can slidably guide both side faces of a second contact array base  31  (described later) (see  FIGS. 4  or  FIG. 5 ). 
     The pair of guide arms  13 ,  13  have opposing grooves  13   d ,  13   d  that extend from a side of the first contact array base  12  to an extremity of the guide arms  13 ,  13 . On the other hand, the socket housing  3   h  has a pair of projecting portions  331 ,  331  on both sides of a base portion  33 . The pair of projecting portions  331 ,  331  protrude in opposite directions and are guided into the grooves  13   d ,  13   d  of the pair of guide arms  13 ,  13 . As the pair of guide arms  13 ,  13  slidably support the both sides of the base portion  33  of the socket housing  3   h , only a back-and-forth movement is allowed for the socket connector  3 . 
     Configuration of First Contact 
     With reference to  FIGS. 3 to 5 , the first contact  11  is composed of a bellows contact that has conductivity, which is a plurality of conductive members in a desired shape obtained by punching or folding a conductive metal plate. In consideration of ease of fabrication, spring characteristics, conductivity, and the like, a copper alloy, for example, is preferably used for the first contact  11 ; however, the present invention is not limited thereto. 
     With reference to  FIGS. 3 to 5  and  7 , the first contact  11  is composed of an extremity portion  11   a  as an elastic arm, an intermediate portion  11   b  as a fixed arm, and a base end portion  11   c  as a lead terminal. In the intermediate portion lib, the conductive members extend linearly and the intermediate portion lib is pressed into the groove portion  12   d  of the first contact array base  12  (see  FIG. 5 ). The base end portion  11   c  protrudes to a side opposite to the guide arms  13 . The base end portion  11   c  is a lead terminal that is inserted into a through hole sh provided on the printed circuit board  1   p , and soldered (see  FIG. 3 ). 
     With reference to  FIG. 5 , the extremity portion  11   a , in which the conductive member is bent at an obtuse angle, extends to an extremity of the intermediate portion  11   b . The extremity portion  11   a  protrudes from the first contact array base  12  to between the pair of guide arms  13 ,  13 . In addition, the extremity portion  11   a  of the first contact  11  can be slidably in contact with the second contact  32  arrayed in the second contact array base  31  (see  FIG. 7 ). 
     Configuration of Reinforcing Tab 
     With reference to  FIGS. 3 to 5 , the base connector  1  further includes, as a metallic tab, a pair of reinforcing tabs  14  and a pair of reinforcing tabs  15   a ,  15   b  with guide springs. The reinforcing tabs  14  are composed of metallic plates that are bent in a crank shape. A first end of the reinforcing tabs  14  is pressed into the base housing  1   h , while a second end thereof is inserted into a through hole provided on the printed circuit board  1   p  and soldered. The base connector  1  is thus fixed onto the printed circuit board  1   p.    
     The pair of reinforcing tabs  15   a ,  15   b  with guide springs are also metallic plates for fixing the base connector  1  onto the printed circuit board  1   p , as the reinforcing tabs  14 . By directing the pair of guide springs  151 ,  151  toward the extremity portions of the pair of guide arms  13 ,  13 , the reinforcing tabs  15   a ,  15   b  can be in contact with the pair of conductive members  35   a ,  35   b.    
     Configuration of Socket Connector 
     With reference to  FIGS. 3 to 5 , the socket connector  3  includes the plate-like socket housing  3   h  and the second contact  32  in the form of eight flat springs. The socket connector  3  includes a substantially rectangular second contact array base  31  and a substantially rectangular base portion  33 . The second contact array base  31  is disposed on a base end of the socket housing  3   h  (see  FIG. 5 ). The second contact array base  31  can engage with the first contact array base  12  so as to overlap the first contact array base  12  (see  FIG. 3 ). 
     Configuration of Socket Housing 
     With reference to  FIGS. 3 to 5 , the socket housing  3   h  is formed of a synthetic resin having insulation properties. On an upper face of the socket housing  3   h , a groove portion  32   d  having eight grooves in comb-teeth form is provided (see FIG.  4  or  FIG. 5 ). The second contact  32  is pressed into the groove portion  32   d  (see  FIG. 5 ). 
     The base portion  33  is disposed at an extremity of the socket housing  3   h  (see  FIG. 5 ). In addition, both sides of the base portion  33  are guided by inner walls of the pair of guide arms  13 ,  13 . Furthermore, a first end of each of a plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  constituting the parallel crank mechanism pcm is rotatably connected to the base portion  33 . The plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  are composed of a first pair of link plates  5   a ,  5   b  and a second pair of link plates  5   c ,  5   d.    
     Configuration of Parallel Crank Mechanism 
     With reference to  FIGS. 3 to 5 , the parallel crank mechanism pcm is composed of the base portion  33 , the upper housing  5 , and the link plates  5   a ,  5   b ,  5   c ,  5   d  in a linked configuration. Pivot pins  5   p  are pressed into both side faces of the base portion  33 , allowing the first end of each of the plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  to be rotatably connected. Meanwhile, the pivot pins  5   p  are pressed into both side faces of the upper housing  5 , allowing the second end of each of the plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  to be rotatably connected. 
     Since the base portion  33  and the upper housing  5  are connected with each other by means of the parallel crank mechanism pcm, the upper housing  5  is always maintained parallel with respect to the base portion  33 . As shown in  FIG. 3  or  FIG. 7  and  FIG. 12 , in the lowered state in which the upper housing  5  is laid toward the front side of the base portion  33 , the socket connector  3  can be either housed in the casing f 1  (see  FIG. 7 ) or pulled out from the casing f 1  (see  FIG. 12 ). 
     On the other hand, as shown in  FIG. 9 , in the raised state in which the upper housing  5  is pulled out from the opening k 1  and raised outside the casing f 1 , the plug  91  can be inserted between the base portion  33  and the upper housing  5 , allowing electrical connection of the plug  91  to the jack  10  (see  FIG. 10  or  FIG. 11  and  FIG. 13 ). 
     With reference to  FIG. 3  or  FIG. 11 , the first pair of link plates  5   a ,  5   b  among the plurality of link plates  5   a ,  5   b ,  5   c ,  5   d , are provided with a pair of opposing guide pawls  51 . The guide pawls  51 ,  51  can guide a pair of side faces  913 ,  913  of the plug housing  91   h  (see  FIG. 6 ). The plug  91  can thus properly connect to the jack  10 , under the control of the pair of guide pawls  51 ,  51 . 
     Configuration of Second Contact 
     With reference to  FIGS. 3 to 5 , the second contact  32  is composed of a bellows contact that has conductivity. In the second contact  32 , a main body, in which a plurality of conductive members extend linearly, is arrayed in the second contact array base  31 . The extremity portion  11   a  of the first contact  11  is slidably in contact with the main body of the second contact  32  (see  FIG. 7  or  8 ). 
     In the extremity portion of the second contact  32 , the bent portion  32   a  in which the conductive members are arrayed in a state of being bent in a folded-back manner is provided (see  FIG. 4 ). When the plug  91  is inserted between the base portion  33  and the upper housing  5 , the contact  91   c , which is a mating-side contact, can be in contact with the bent portion  32   a  (see  FIG. 6  or  10 ). 
     Configuration of Conductive Members 
     With reference to  FIG. 5 , the socket connector  3  further includes the pair of conductive members  35   a ,  35   b . In the pair of conductive members  35   a ,  35   b , respective base end portions thereof fit into the socket housing  3   h  and are in contact with the guide springs  151 ,  151  of the pair of reinforcing tabs  15   a ,  15   b , respectively. Meanwhile, respective extremity portions  351 ,  351  of the pair of conductive members  35   a ,  35   b  protrude slightly from the front face of the socket housing  3   h  (see  FIG. 13 ). If a human body touches the extremity portion  351  of the pair of conductive members  35   a ,  35   b , an electrical charge of the human body can be released to the printed circuit board  1   p  via the reinforcing tabs  15   a ,  15   b.    
     Operation of Modular Jack 
     Operations and effects of the jack  10  of the first embodiment are described hereinafter by explaining behavior thereof, while giving complementary descriptions on the configuration of the jack  10 . 
       FIG. 14A  is a cross-sectional view taken along a line A-A of  FIG. 7  illustrating a configuration of the modular jack of the first embodiment; and  FIG. 14B  is an enlarged view of a main portion of  FIG. 14A .  FIG. 15A  is a cross-sectional view taken along a line A-A of  FIG. 8  illustrating a configuration of the modular jack of the first embodiment;  FIG. 15B  is an enlarged view of a main portion of  FIG. 15A . 
       FIG. 16  is a cross-sectional view taken along a line A-A of  FIG. 9  illustrating a configuration of the modular jack of the first embodiment.  FIG. 17  is a cross-sectional view taken along a line A-A of  FIG. 10  illustrating a configuration of the modular jack of the first embodiment. 
     As shown in  FIG. 1A  or  2 A, the jack  10  is usually stored inside the casing f 1 . The opening k 1  provided on the side face of the casing f 1  is shut by the front face of the upper housing  5 . 
     In the state shown in  FIG. 1A  or  2 A, the socket connector  3  fits into the base connector  1  (see  FIG. 3  or  7 ). With reference to  FIG. 14B , a first stop projection  131  is provided on the rear side of the groove  13   d  of the guide arm  13 . As the first stop projection  131  engages with the projecting portion  331 , the socket housing  3   h  is maintained in a stored state with respect to the base housing  1   h . By pulling the socket housing  3   h  away from the base housing  1   h  with a force such that the projecting portion  331  can run over the first stop projection  131 , the socket housing  3   h  can be pulled out from the base housing  1   h.    
     For connecting the plug  91  to the jack  10 , the socket connector  3  is first pulled out from the casing f 1 . In this case, since a concavity is provided on the bottom face of the upper housing  5  as shown in  FIG. 7  or  8 , the socket connector  3  can be easily pulled out. 
       FIG. 1B  or  FIG. 2B  and  FIG. 8  are diagrams illustrating a state in which the socket connector  3  is completely pulled out from the casing f 1 . In this case, as shown in  FIG. 15B , a second stop projection  132  is provided on an entrance side of the groove  13   d . The projecting portion  331  thus engages with the second stop projection  132 . As a result, the socket housing  3   h  is stably maintained in a pulled out state with respect to the base housing  1   h . By pulling the socket housing  3   h  away from the base housing  1   h  with a force such that the projecting portion  331  can run over the second stop projection  132 , the socket housing  3   h  is released from the stably maintained state. This can prevent, for example, damage to the base connector  1 . 
     From the state shown in  FIG. 1B  or  FIG. 2B  and  FIG. 8 , by rotating the upper housing  5  in a first direction as shown in  FIG. 1C  or  2 C, the upper housing  5  goes into the raised state outside the casing f 1  (see  FIG. 9  or  FIG. 11  and  FIG. 13 ). The plug  91  can thus be inserted between the base portion  33  and the upper housing  5 , to be electrically connected to the jack  10  (see  FIG. 1D  or  FIG. 2D ). 
     In the state shown in  FIG. 1D  or  FIG. 2D , the pair of engaging pawls  91   n ,  91   n  of the plug  91  engage with a notched groove  5   k  provided on the upper housing  5  (see  FIG. 13 ). The plug  91  can thus be locked into the socket connector  3 . In addition, in the state shown in  FIG. 1D  or  FIG. 2D , the plug  91  and the printed circuit board  1   p  are electrically connected with each other in a sequential path of: the contact  91   c , the second contact  32 , and the first contact  11 . 
     For disconnecting the plug  91 , the plug  91  can be released and the socket connector  3  can be stored inside the casing f 1  by the above described procedure in reverse order. 
     In the jack  10  of the first embodiment, in a state in which the upper housing  5  is laid toward the front side of the socket housing  3   h , the socket connector  3  can be housed inside the casing f 1 . In other words, in the lowered state of the upper housing  5 , both faces of the upper housing  5 , the socket housing  3   h , and the base housing  1   h  are formed in a flat plate-like shape. As a result, with the jack  10  a modular jack of a reduced height can be provided, to realize a reduction in size of an electronic device. 
     Second Embodiment 
     Configuration of Modular Jack 
     Next, a configuration of a modular jack according to a second embodiment of the present invention is described.  FIGS. 18A to 18D  are perspective views illustrating a configuration of the modular jack according to the second embodiment of the present invention.  FIG. 18A  is a diagram illustrating a state in which the modular jack of the second embodiment is housed inside a casing;  FIG. 18B  is a diagram illustrating a state in which a socket connector provided in the modular jack of the second embodiment is pulled out from the casing;  FIG. 18C  is a diagram illustrating a state in which the upper housing provided in the socket connector is raised from the state shown in  FIG. 18B ; and  FIG. 18D  is a diagram illustrating a state in which a modular plug is connected to the modular jack in the state shown in  FIG. 18C . 
       FIGS. 19A to 19D  are perspective views illustrating a configuration of the modular jack according to the second embodiment, showing the casing with imaginary lines.  FIG. 19A  is a diagram illustrating a state in which the modular jack of the second embodiment is housed inside the casing;  FIG. 19B  is a diagram illustrating a state in which a socket connector provided in the modular jack of the second embodiment is pulled out from the casing;  FIG. 19C  is a diagram illustrating a state in which the upper housing provided in the socket connector is raised from the state shown in  FIG. 19B ; and  FIG. 19D  is a diagram illustrating a state in which a modular plug is connected to the modular jack in a state shown in  FIG. 19C . 
       FIG. 20  is a perspective view illustrating a configuration of the modular jack of the second embodiment, disposed to face a printed circuit board inside the casing.  FIG. 21  is a perspective view illustrating a configuration of the modular jack of the second embodiment in a state in which the base housing composing the modular jack and the socket connector are disposed to face each other.  FIG. 22  is an exploded perspective view illustrating a configuration of the modular jack of the second embodiment. 
     Overall Configuration 
     With reference to  FIGS. 18 to 22 , the jack  20  of the second embodiment is provided with a base connector  2  and the socket connector  4 . The base connector  2  is mounted on the printed circuit board  2   p . The printed circuit board  2   p  is disposed inside the flat casing f 2  with a rectangular opening k 2  on a side face thereof. The flat casing f 2  is illustrated as a part of a casing of the electronic device. A side wall of the base connector  2  is held along an edge portion of the printed circuit board  2   p . More specifically, the side wall of the base connector  2  is held in a slot cutout s 2 , which faces the opening k 2 , on the printed circuit board  2   p . The slot cutout s 2  has a rectangular shape composed of three sides made on the printed circuit board  2   p . The socket connector  4  is slidably connected to the base connector  2 . The socket connector  4  is also provided with a parallel crank mechanism pcm at an extremity portion thereof. The parallel crank mechanism pcm allows switching of the upper housing  6 , which can engage with the latching tab  91   r , between the lowered state and the raised state. 
     Configuration of Modular Jack 
       FIG. 23  is a vertical cross-sectional view illustrating a configuration of the modular jack of the second embodiment in a state in which the socket connector provided in the modular jack of the second embodiment is housed inside the casing. 
       FIG. 24  is a vertical cross-sectional view illustrating a configuration of the modular jack of the 2 embodiment in a state in which the socket connector provided in the modular jack is pulled out from the casing. 
       FIG. 25  is a vertical cross-sectional view illustrating a configuration of the modular jack of the 2 embodiment in a state in which the upper housing provided in the socket connector is raised.  FIG. 26  is a vertical cross-sectional view illustrating a configuration of the modular jack of the 2 embodiment in a state in which the modular plug is connected to the modular jack. 
     Configuration of Base Connector 
     With reference to  FIGS. 20 to 22 , the base connector  2  includes the plate-like base housing  2   h  and the first contact  21  in the form of eight flat springs. The base housing  2   h  is provided with a concave portion  22  in a substantially rectangular shape, and the first contact array base  23 . The concave portion  22  is surrounded by: a pair of opposing first side walls  22   a ,  22   b ; and a second side wall  22   c  that connects first ends of the first side walls  22   a ,  22   b . The first contact array base  23  is formed in a central portion of a bottom wall of the concave portion  22  (see  FIG. 22 ). 
     Configuration of Base Housing 
     With reference to  FIG. 21  or  22 , the base housing  2   h  is formed of a synthetic resin having insulation properties. On the bottom face of the concave portion  22  of the base housing  2   h , a groove portion  23   d  having eight grooves in comb-teeth form is provided. A part of the groove portion  23   d  penetrates into the bottom face of the concave portion  22  and a bottom face of the base housing  2   h , as well as into the second side wall  22   c . An intermediate portion  21   b  of the first contact  21  is pressed into the groove portion  23   d  (see  FIG. 22 ). Three peripheral sides of the base housing  2   h  are surrounded by the slot cutout s 2 . 
     The pair of first side walls  22   a ,  22   b  have opposing grooves  22   d ,  22   d  that extend from the second side wall  22   c  to extremities of the first side walls  22   a ,  22   b . On the other hand, the socket housing  4   h  has a pair of projecting portions  431 ,  431  on both sides thereof. The pair of projecting portions  431 ,  431  protrude in opposite directions and are guided by the grooves  22   d ,  22   d  of the first side walls  22   a ,  22   b  on the base housing  2   h . As the pair of first side walls  22   a ,  22   b  slidably support the two sides of the socket housing  4   h , only a back-and-forth movement is allowed for the socket connector  4 . 
     Configuration of First Contact 
     With reference to  FIG. 21  or  22 , the first contact  21  is composed of a bellows contact that has conductivity, which is a plurality of conductive members in a desired shape obtained by punching or folding a conductive metal plate. In consideration of ease of fabrication, spring characteristics, conductivity and the like, a copper alloy, for example, is preferably used for the first contact  21 ; however, the present invention is not limited thereto. 
     With reference to  FIG. 22  or  24 , the first contact  21  is composed of an extremity portion  21   a  as an elastic arm, an intermediate portion  21   b  as a fixed arm, and a base end portion  21   c  as a lead terminal. In the intermediate portion  21   b , the conductive members extend linearly and the intermediate portion  21   b  is pressed into the groove portion  23   d  of the first contact array base  23  (see  FIG. 22 ). The base end portion  21   c  protrudes to the outside of the second side wall  22   c . The base end portion  21   c  is a lead terminal that is inserted into a through hole sh provided on the printed circuit board  2   p , and soldered (see  FIG. 20 ). 
     With reference to  FIG. 22  or  24 , the extremity portion  21   a , in which the conductive member is bent upward at an obtuse angle, extends to an extremity side of the intermediate portion  21   b . The extremity portion  21   a  protrudes from the bottom wall of the concave portion  22  (see  FIG. 21 ). In addition, the extremity portion  21   a  of the first contact  21  can be in contact with the second contact  42  arrayed in the second contact array base  41  (see  FIG. 24 ). 
     Configuration of Reinforcing Tab 
     With reference to  FIGS. 20 to 22 , the base connector  2  further includes, as a metallic tab, a pair of reinforcing tabs  24 ,  24  and a pair of reinforcing tabs  25   a ,  25   b  with guide springs. The reinforcing tabs  24  are composed of metallic plates that are bent in a crank shape. A first end of the reinforcing tabs  24  is pressed into the base housing  2   h , while a second end thereof is inserted into a through hole provided on the printed circuit board  2   p  and soldered. The base connector  2  is thus fixed onto the printed circuit board  2   p.    
     The pair of reinforcing tabs  25   a ,  25   b  with guide springs are also metallic plates for fixing the base connector  2  onto the printed circuit board  2   p , as the reinforcing tabs  24 . By directing the pair of guide springs  251 ,  251  toward the extremity portions of the pair of first side walls  22   a ,  22   b , the reinforcing tabs  25   a ,  25   b  can be in contact with the pair of conductive members  45   a ,  45   b.    
     Configuration of Socket Connector 
     With reference to  FIGS. 20 to 22 , the socket connector  4  includes the plate-like socket housing  4   h  and the second contact  42  in the form of eight flat springs. The second contact array base  41  is disposed in a central portion of the socket housing  4   h . The second contact  42  is arrayed in the second contact array base  41 . In addition, in the socket housing  4   h , connecting portions  43 ,  43  are provided on both side portions of the second contact array base  41 . In addition, the second contact array base  41  faces the first contact array base  23  so as to overlap the first contact array base  23  (see  FIG. 22 ). 
     Configuration of Socket Housing 
     With reference to  FIG. 21  or  22 , a socket housing  4   h  is formed of a synthetic resin having insulation properties. On an upper face of the socket housing  4   h , a groove portion  42   d  having eight grooves in comb-teeth form is provided (see  FIG. 22 ). The second contact  42  is pressed into the groove  42   d  (see  FIG. 22 ). 
     With reference to  FIGS. 20 to 22 , the connecting portions  43  are disposed on both side portions of the socket housing  4   h . In addition, both side faces of the connecting portions  43  are guided by inner walls of the pair of first side walls  22   a ,  22   b  of the base connector  2 . Furthermore, a first end of each of a plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  constituting the parallel crank mechanism pcm is rotatably connected to the connecting portions  43 . The plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  are composed of a first pair of link plates  5   a ,  5   b  and a second pair of link plates  5   c ,  5   d.    
     Configuration of Parallel Crank Mechanism 
     With reference to  FIGS. 20 to 22 , the parallel crank mechanism pcm is composed of the connecting portion  43 , the upper housing  6 , and the link plates  5   a ,  5   b ,  5   c ,  5   d  in a linked configuration. Pivot pins  5   p  are pressed into both side faces of the connecting portion  43 , allowing the first end of each of the plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  to be rotatably connected. Meanwhile, the pivot pins  5   p  are pressed into both side faces of the upper housing  6 , allowing the second ends of the plurality of link plates  5   a ,  5   b ,  5   c  and  5   d  to be rotatably connected. It should be noted that the upper housing  5  of the first embodiment and the upper housing  6  of the second embodiment are the same, but are distinguished by changing reference symbols for clarity of description. 
     Since the connecting portion  43  and the upper housing  6  are connected with each other by means of the parallel crank mechanism pcm, the upper housing  6  is always maintained parallel with respect to the base portion  43 . As shown in  FIG. 23  or  FIG. 24 , in the lowered state in which the upper housing  6  is laid toward the front side of the connecting portion  43 , the socket connector  4  can be either housed in the casing f 2  (see  FIG. 23 ) or pulled out from the casing f 2  (see  FIG. 24 ). 
     On the other hand, as shown in  FIG. 25 , in the raised state in which the upper housing  6  is pulled out from the opening k 2  and raised outside the casing f 2 , the plug  91  can be inserted between the connecting portion  43  and the upper housing  6 , allowing electrical connection of the plug  91  to the jack  20  (see  FIG. 26 ). 
     With reference to  FIG. 22 , the first pair of link plates  5   a ,  5   b  among the plurality of link plates  5   a ,  5   b ,  5   c ,  5   d , are provided with a pair of opposing guide pawls  51 . The guide pawls  51 ,  51  can guide a pair of side faces  913 ,  913  of the plug housing  91   h  (see  FIG. 6 ). The plug  91  can thus properly connect to the jack  20 , under the control of the pair of guide pawls  51 ,  51 . 
     Configuration of Second Contact 
     With reference to  FIGS. 20 to 22 , the second contact  42  is composed of a bellows contact that has conductivity. In the second contact  42 , a main body, in which a plurality of conductive members extend linearly, is arrayed in the second contact array base  41 . The extremity portion  21   a  of the first contact  21  is in contact with a reverse face side of the main body of the second contact  42  (see  FIG. 24  or  25 ). 
     In the extremity portion of the second contact  42 , the bent portion  42   a  in which the conductive members are arrayed in a state of being bent in a folded-back manner is provided. The bent portion  42   a  is arrayed at an extremity of the socket housing  4   h  (see  FIG. 21 ). When the plug  91  is inserted between the connecting portion  43  and the upper housing  6 , the contact  91   c , which is a mating-side contact, can be in contact with the bent portion  42   a  (see  FIG. 6  or  26 ). 
     Configuration of Conductive Members 
     With reference to  FIG. 22 , the socket connector  4  further includes the pair of conductive members  45   a ,  45   b . In the pair of conductive members  45   a ,  45   b , respective base end portions thereof fit into the socket housing  4   h  and are in contact with the pair of reinforcing tabs  25   a ,  25   b , respectively. Meanwhile, respective extremity portions  451 ,  451  of the pair of conductive members  45   a ,  45   b  protrude slightly from the front face of the socket housing  4   h . If a human body touches the extremity portion  451  of the pair of conductive members  45   a ,  45   b , an electrical charge of the human body can be released to the printed circuit board  2   p  via the reinforcing tabs  25   a ,  25   b.    
     Operation of Modular Jack 
     Operations and effects of the jack  20  of the second embodiment are described hereinafter by explaining behavior thereof, while giving complementary descriptions on the configuration of the jack  20 . 
       FIG. 27A  is a cross-sectional view taken along a line A-A of  FIG. 23  illustrating a configuration of the modular jack of the second embodiment; and  FIG. 27B  is an enlarged view of a main portion of  FIG. 27A .  FIG. 28A  is a cross-sectional view taken along a line A-A of  FIG. 24 ; and  FIG. 28B  is an enlarged view of a main portion of  FIG. 28A . 
       FIG. 29  is a cross-sectional view taken along a line A-A of  FIG. 25  illustrating a configuration of the modular jack of the second embodiment.  FIG. 30  is a cross-sectional view taken along a line A-A of  FIG. 26  illustrating a configuration of the modular jack of the second embodiment. 
     As shown in  FIG. 18A  or  19 A, the jack  20  is usually stored inside the casing f 2 . The opening k 2  provided on the side face of the casing f 2  is shut by the front face of the upper housing  6 . 
     In the state shown in  FIG. 18A  or  19 A, the socket connector  4  fits into the base connector  2  (see  FIG. 20  or  23 ). With reference to  FIG. 27B , a first stop projection  231  is provided on the rear side of the groove  22   d . As the first stop projection  231  engages with the projecting portion  431 , the socket housing  4   h  is maintained in a stored state with respect to the base housing  2   h . By pulling the socket housing  4   h  away from the base housing  2   h  with a force such that the projecting portion  431  can run over the first stop projection  231 , the socket housing  4   h  can be pulled out from the base housing  2   h.    
     For connecting the plug  91  to the jack  20 , the socket connector  4  is first pulled out from the casing f 2 . In this case, since a concavity is provided on a bottom face of the upper housing  6  as shown in  FIG. 24  or  25 , the socket connector  4  can be easily pulled out. 
       FIG. 18B  or  FIG. 19B  and  FIG. 24  are diagrams illustrating a state in which the socket connector  4  is completely pulled out from the casing f 2 . In this case, as shown in  FIG. 28B , since a second stop projection  232  is provided on an entrance side of the groove  22   d , the projecting portion  431  engages with the second stop projection  232 . As a result, the socket housing  4   h  is stably maintained in a pulled out state with respect to the base housing  2   h . By pulling the socket housing  4   h  away from the base housing  2   h  with a force such that the projecting portion  431  can run over the second stop projection  232 , the socket housing  4   h  is released from the stably maintained state. This can prevent, for example, damage to the base connector  2 . 
     From the state shown in  FIG. 18B  or  FIG. 19B  and  FIG. 24 , by rotating the upper housing  6  to a first direction as shown in  FIG. 18C  or  19 C, the upper housing  6  goes into the raised state outside the casing f 2  (see  FIG. 25 ). The plug  91  can thus be inserted between the connecting portion  43  and the upper housing  6 , to be electrically connected to the jack  20  (see  FIG. 18D  or  FIG. 19D ). 
     In the state shown in  FIG. 18D  or  FIG. 19D , the pair of engaging pawls  91   n ,  91   n  of the plug  91  engage with a notched groove  6   k  provided on the upper housing  6  (see  FIG. 21 ). The plug  91  can thus be locked into the socket connector  4 . In addition, in the state shown in  FIG. 18D  or  FIG. 19D , the plug  91  and the printed circuit board  2   p  are electrically connected with each other in a sequential path of: the contact  91   c , the second contact  42 , and the first contact  21 . 
     For disconnecting the plug  91 , the plug  91  can be released and the socket connector  4  can be stored inside the casing f 2  by the above described procedure in reverse order. 
     In the jack  20  of the second embodiment, in a state in which the upper housing  6  is laid toward the front side of the socket housing  4   h , the socket connector  4  can be housed inside the casing f 2 . In other words, when the upper housing  6  is in the lowered state, the upper housing  6  and the socket housing  4   h  can be stored inside the concave portion  22  of the base housing  2   h  and the upper faces thereof are made flat. As a result, with the jack  20 , a modular jack of a reduced height can be provided, to realize a reduction in size of an electronic device. In addition, the jack  20  has a further advantage of requiring a smaller area on a printed circuit board than the jack  10  of the first embodiment.