Patent Publication Number: US-6981898-B2

Title: Connector

Description:
This application is a continuing application, filed under 35 U.S.C. §111(a), of International Application PCT/JP02/00677, filed Jan. 30, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to connectors that are used in computers, servers, and routers, and more particularly, to a connector that has multiple pairs of signal contacts and is suitable especially for balanced transmission. 
     2. Description of the Related Art 
     In recent years, there has been an increasing demand for a large amount of data transmission, as computers and computer networks have been rapidly developed. Especially, video data transmission needs to be carried out at a speed of 1 Gbit/s or higher. 
     For this type of data transmission, unbalanced transmission methods have been widely employed conventionally, because they are advantageous in terms of costs. By the unbalanced transmission methods, however, it is difficult to avoid adverse influence of noise. Therefore, to carry out high-speed data transmission, it is more preferable to employ a balanced transmission method that can provide resistibility to noise. 
       FIGS. 1A and 1B  illustrate an example of a conventional connector device of a balanced transmission type. The connector device shown in  FIG. 1A  has a jack connector  1  and a mating plug connector  2 . 
     The jack connector  1  includes pairs of signal contacts  4   a  and  4   b  and ground contacts  5   a  in a housing  3   a  that is made of an insulating material and is formed longitudinally in the direction of X 1 -X 2  of  FIG. 1A . 
     The housing  3   a  has a concavity  6   a  formed longitudinally in the direction of X 1 -X 2 . Each pair of signal contacts  4   a  and  4   b  has upper ends  4   a - 1  and  4   b - 1  protruding in the direction of Z 1  from the bottom wall  3   a - 1  of the housing  3   a  and extending along the side walls  3   a - 2  and  3   a - 3  within the concavity  6   a . The signal contacts  4   a  and  4   b  in each pair face each other in the direction of Y 1 -Y 2 . A ground contact  5   a  having a fork-like top end  5   a - 1  is provided between each two neighboring pairs of signal contacts  4   a  and  4   b.    
     The lower ends  4   a - 2 ,  4   b - 2 , and  5   a - 2  (not shown) of the signal contacts  4   a  and  4   b  and the ground contacts  5   a  each has a pin-like shape extending in the direction of Z 2  and is inserted into a hole  7   a  formed in a substrate  8   a . In this structure, the lower ends  4   a - 2 ,  4   b - 2 , and  5   a - 2  are connected to a printed circuit (not shown) formed on the substrate  8   a.    
     The plug connector  2  has a shape corresponding to the jack connector  1 , and includes pairs of signal contacts  4   c  and  4   d  and ground contacts  5   b  in a housing  3   b  that is made of an insulating material and is formed longitudinally in the direction of X 1 -X 2  of  FIG. 1B . 
     The housing  3   b  has protrusions  3   b - 1  arranged at predetermined intervals in the direction of X 1 -X 2  within a concavity  6   b . Each pair of signal contacts  4   c  and  4   d  has pin-like upper ends  4   c - 1  and  4   d - 1  protruding from the bottom wall  3   b - 2  of the housing  3   b  and extending along the both sides of each corresponding protrusion  3   b - 1  in the direction of Y 1 -Y 2 . A ground contact  5   b  having a flat top end  5   b - 1  is provided between each two neighboring pairs of signal contacts  4   c  and  4   d.    
     The lower ends  4   c - 2 ,  4   d - 2 , and  5   b - 2  (not shown) of the signal contacts  4   c  and  4   d  and the ground contacts  5   b  each has a tongue-like top end that is bent in the direction of Y 1 -Y 2  of  FIG. 1B . This tongue-like top end is fixed to a pad (not shown) formed on a substrate  8   b , and is thus connected to a printed circuit (not shown) formed on the substrate  8   b.    
     The plug connector  2  is connected to the jack connector  1 , so that the signal contacts  4   a  and  4   b  are brought into contact with the signal contacts  4   c  and  4   d , and that the ground contacts  5   a  sandwich the corresponding ground contacts  5   b . Thus, the signal contacts and the ground contacts are electrically connected to one another. If a positive signal is transmitted through the signal contacts  4   a  and  4   c  in this case, a negative signal is transmitted through the signal contacts  4   b  and  4   d.    
     With the above conventional connector device, however, there is a problem that desired balanced transmission cannot be carried out, because the mating lower ends  4   c - 2  and  4   d - 2  extend in the opposite directions and cannot establish preferable coupling. 
     Meanwhile, a wiring pattern may be formed on the substrates, so that one ends of the wires extend from either one side (the Y 1  side or the Y 2  side in  FIG. 1B ) of the longitudinal walls of the housings  3   a  and  3   b , while the other ends of the wires are connected to a terminal unit or the like provided at a predetermined location on a line extending from the one side. In such a case, however, wires of uniform lengths cannot be provided between the terminal unit and each pair of signal contacts, because one of the signal contacts in each pair is located farther away from the terminal unit. The variation of the wire lengths causes phase difference between signals subject to balanced transmission through each pair of signal contacts. The phase difference results in noise, and makes the characteristic impedance unstable. 
     To prevent the noise generation and stabilize the characteristic impedance, the lengths of wires to be connected to the signal contacts closer to the terminal unit are adjusted to the same lengths as the lengths of the wires to be connected to the signal contacts farther from the terminal unit. 
     However, the employment of wires at the unnecessary locations, i.e., the excessive lengths of wires, only complicates the wiring design and the wiring operation for the substrates. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a connector that has multiple pairs of signal contacts arranged in a housing, and facilitates the wiring design and the wiring operation for substrates. 
     The connector of the present invention has multiple pairs of signal contacts arranged in a housing. In this connector, the two adjacent signal contacts that are paired with each other are arranged at a distance in the longitudinal direction of the housing. When the signal contacts of the connector are connected to a terminal unit or the like of a substrate facing in a direction perpendicular to the longitudinal direction of the housing, the lengths of each pair of wires for connecting the multiple pairs of signal contacts to the terminal unit or the like can be made uniform. Accordingly, there is no need to prepare excessive wiring areas, and the wiring design and the wiring operation for substrates can be simplified. 
     Here, the connector is either a jack connector or a plug connector. In this connector, the multiple pairs of signal contacts are of a surface mounting type, and have bent ends in contact with a pad on a substrate. The effects of the present invention can be maximized if these bent ends of all the multiple pairs of signal contacts extend in parallel with one another. However, the arrangement of the signal contacts is not limited to this, and each of the signal contacts may have a pin-like top end to be inserted into each corresponding through hole formed in the substrate. In such a case, the multiple pairs of signal contacts are aligned in arrays in the transverse direction of the housing, so that the effects of the present invention can be maximized in the wiring design and the wiring operation for a number of substrates required in accordance with the number of the arrays of signal contacts. 
     The connector of the present invention may further include an array internal ground contact between each neighboring pairs of the multiple pairs of signal contacts. With this arrangement, crosstalk between each two neighboring pairs of signal contacts can be reduced. The array internal ground contact is large enough to shield the multiple pairs of signal contacts from each neighboring pair. 
     The connector of the present invention may further include an array intermediate ground contact between each two neighboring arrays of the multiple pairs of signal contacts. With this arrangement, crosstalk between each two neighboring arrays of the multiple pairs of signal contacts can be reduced. The array intermediate ground contact has an exposed flat panel part in the housing. Also, the length of the housing in the longitudinal direction is greater than the distance between each pair of signal contacts of the multiple pairs of signal contacts. 
     The connector of the present invention may further include a shielding layer that is formed on the exterior of the housing. The shielding layer effectively shields the connector from external electromagnetic waves. 
     In the connector of the present invention, each of the multiple pairs of signal contacts prevents noise between each pair of signal contacts through which signals travel in balanced transmission. Thus, the characteristic impedance can be stabilized even in a high-speed signal transmitting operation. 
     The present invention also provides a connector that includes: signal contacts that are arranged in two arrays; and ground contacts that divide each array of signal contacts into multiple pairs. In this connector, the multiple pairs of signal contacts are adjacent to one another over the entire length of each signal contact. Accordingly, coupling is established between each pair of signal contacts, and excellent balanced transmission can be carried out. Also, when the connector is mounted to a substrate, pairs of wires for connecting each pair of signal contacts to a terminal unit or the like on the substrate can be made uniform, because the multiple pairs of signal contacts are adjacent to one another. Accordingly, there is no need to prepare excessive wiring areas on the substrate, and the substrate wiring design and the wiring operation can be simplified. 
     In the above structure, substrate contact parts of the multiple pairs of signal contacts arranged in one of the two arrays may extend in the opposite direction from substrate contact parts of the multiples pairs of signal contacts arranged in the other one of the two arrays. Accordingly, each two adjacent signal contacts of the two arrays extend in the opposite directions. Thus, excellent high-density balanced transmission can be realized. 
     In the above structure, substrate contact parts of the multiple pairs of signal contacts arranged in one of the two arrays may face substrate contact parts of the multiple pairs of signal contacts arranged in the other one of the two arrays, and all the substrate contact parts extend in the same direction. Accordingly, the multiple pairs of signal contacts adjacent to one another are arranged on the two opposite faces of the substrate. Thus, excellent high-density balanced transmission can be realized. 
     In the above structure, a pair of signal contacts arranged in one of the two arrays and a pair of signal contacts arranged in the other one of the two arrays may exist between each two neighboring ground contacts. With this arrangement, each pair of signal contacts can be effectively shielded from the neighboring pairs of signal contacts. 
     In the above structure, a pair of signal contacts arranged in one of the two arrays and a pair of signal contacts arranged in the other array that faces the one of the two arrays via an insulating member may exist between each two neighboring ground contacts. With this arrangement, a plug connector can be formed. 
     In the above structure, a pair of signal contacts arranged in one of the two arrays and a pair of signal contacts arranged in the other array that faces the one of the two arrays via a space may exist between each two neighboring ground contacts. With this arrangement, a jack connector can be formed. 
     In the above structure, the ground contacts may each have a panel-like shape, and be provided in both two arrays. This is an example of the structure of a ground contact. 
     In the above structure, each of the ground contacts may be provided across both two arrays, and have two substrate contact parts facing each other. Accordingly, the ground contacts have the same structures as the signal contacts, and thus are extended toward the substrate. 
     In the above structure, each of the ground contacts may have a pair of contact parts. In this case, one of the pair of contact parts is aligned with substrate contact parts of the multiple pairs of signal contacts arranged in one of the two arrays, while the other one of the pair of contact parts is aligned with substrate contact parts of the multiple pairs of signal contacts arranged in the other one of the two arrays. With this arrangement, the substrate contact parts of the ground contacts can be aligned with the substrate contact parts of the signal contacts. Thus, the substrate wiring design and wiring operation can be further simplified. 
     In the above structure, first parts of the signal contacts to be connected to a mating connector may extend in a direction perpendicular to second parts of the signal contacts to be connected to terminals on the substrate. Alternatively, the first parts of the signal contacts to be connected to a mating connector may extend in the opposite direction from the second parts of the signal contacts to be connected to terminals on the substrate. 
     In the above structure, the signal contacts arranged in the two arrays may be aligned at intervals in the longitudinal direction of the connector. 
     The connector of the present invention may further include other signal contacts that are provided in each array. These other signal contacts in each array are arranged at intervals, without the ground contacts being interposed among the other signal contacts. The arrangement of signal contact without ground contact is suitable for unbalanced transmission at a relatively low speed. Accordingly, a complex connector that is suitable for both balanced transmission and unbalanced transmission can be realized with the above structure. 
     The present invention also provides an electronic device that includes a wiring substrate and a connector that is mounted to the wiring substrate. In this electronic device, the connector is one of the above described connectors of the present invention. This electronic device may be a printed wiring board to which one of the connectors of the present invention is mounted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of a jack connector that is a part of a conventional connector device; 
         FIG. 1B  is a perspective view of a plug connector that is a part of the conventional connector device; 
         FIG. 2A  is a perspective view of a jack connector in accordance with a first embodiment of the present invention; 
         FIG. 2B  is a perspective view of a plug connector in accordance with the first embodiment of the present invention; 
         FIG. 3  is a sectional view of the jack connector, taken along the line III—III of  FIG. 2A ; 
         FIG. 4  is a perspective view of an array internal ground contact and an array intermediate ground contact of the plug connector of  FIG. 2B ; 
         FIG. 5  is a sectional view of the plug connector, taken along the line V—V of  FIG. 2B ; 
         FIG. 6A  illustrates a signal contact in the connection mechanism between the jack connector of  FIG. 2A  and the plug connector of  FIG. 2B ; 
         FIG. 6B  illustrates ground contacts in the connection mechanism between the jack connector of  FIG. 2A  and the plug connector of  FIG. 2B ; 
         FIG. 7A  is a perspective view of a jack connector in accordance with a second embodiment of the present invention; 
         FIG. 7B  is a perspective view of a plug connector in accordance with the second embodiment of the present invention; 
         FIG. 8A  is a sectional view of the jack connector, taken along the line IX—IX of  FIG. 7A , and illustrates the situation immediately before the connecting process; 
         FIG. 8B  is a sectional view of the plug connector, taken along the line IX—IX of  FIG. 7B , and illustrates the situation immediately before the connecting process; 
         FIG. 9  is a sectional view illustrating the connection mechanism between the jack connector and the plug connector in a connected state, taken along the line IX—IX of  FIGS. 7A and 7B ; 
         FIG. 10A  is a perspective view of a plug connector in accordance with a third embodiment of the present invention; 
         FIG. 10B  is a partially cutaway perspective view of the plug connector in accordance with the third embodiment of the present invention; 
         FIG. 10C  is a sectional view of the plug connector, taken along the line X C  of  FIG. 10B ; 
         FIG. 10D  is a sectional view of the plug connector, taken along the line X D  of  FIG. 10B ; 
         FIG. 11A  is a perspective view of a jack connector in accordance with the third embodiment of the present invention; 
         FIG. 11B  is a partially cutaway perspective view of the jack connector in accordance with the third embodiment of the present invention; 
         FIG. 11C  is a sectional view of the jack connector, taken along the line XI C  of  FIG. 11B ; 
         FIG. 11D  is a sectional view of the jack connector, taken along the line XI D  of  FIG. 11B ; 
         FIG. 12A  is a perspective view of a jack connector in accordance with a fourth embodiment of the present invention; 
         FIG. 12B  is a partially cutaway perspective view of the jack connector in accordance with the fourth embodiment of the present invention; 
         FIG. 12C  is a sectional view of the jack connector, taken along the line XII C  of  FIG. 12B ; 
         FIG. 12D  is a sectional view of the jack connector, taken along the line XII D  of  FIG. 12B ; 
         FIG. 13A  is a perspective view of a plug connector in accordance with a fifth embodiment of the present invention; 
         FIG. 13B  is a partially cutaway perspective view of the plug connector in accordance with the fifth embodiment of the present invention; 
         FIG. 13C  is a sectional view of the plug connector, taken along the line XIII C  of  FIG. 13B ; 
         FIG. 13D  is a sectional view of the plug connector, taken along the line XIII D  of  FIG. 13B ; 
         FIG. 14A  is a perspective view of a plug connector that is a modification of the third embodiment of the present invention; 
         FIG. 14B  is a partially cutaway perspective view of the plug connector that is a modification of the third embodiment; 
         FIG. 15A  is a perspective view of a jack connector that is a modification of the third embodiment of the present invention; 
         FIG. 15B  is a partially cutaway perspective view of the jack connector that is a modification of the third embodiment; 
         FIG. 16A  is a perspective view of a jack connector that is a modification of the fourth embodiment of the present invention; 
         FIG. 16B  is a partially cutaway perspective view of the jack connector that is a modification of the fourth embodiment; 
         FIG. 17A  is a perspective view of a plug connector that is a modification of the fifth embodiment of the present invention; and 
         FIG. 17B  is a partially cutaway perspective view of the plug connector that is a modification of the fifth embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is a detailed description of preferred embodiments of the present invention, with reference to the accompanying drawings. 
     First Embodiment 
     Referring first to  FIGS. 2A through 6B , a connector in accordance with a first embodiment of the present invention will be described. 
     The connector in accordance with this embodiment is made up of a jack connector and a plug connector that can be connected to the jack connector. The jack connector and the plug connector are set as a pair on substrates, so as to connect multiple substrates to one another. The wiring substrates onto which the connectors of the present invention are mounted are one embodiment of an electronic device of the present invention. 
     A jack connector  10  has an array of pairs of signal contacts  14   a  and  14   b , another array of pairs of signal contacts  114   a  and  114   b , and ground contacts  16  in a housing  12  that is made of an insulating material and is formed longitudinally in the direction of X 1 -X 2  of  FIG. 2A . 
     The housing  12  has a slit  18  that is formed longitudinally in the direction of X 1 -X 2 , and short slits  20  that cross the slit  18  at right angles. Each area surrounded by the slit  18  and the slits  20  has a pair of holes  22   a  and  22   b  formed therein. Accordingly, the holes  22   a  and  22   b  are arranged as multiple pairs in the direction of X 1 -X 2 , and as two arrays in the direction of Y 1 -Y 2 . Each of the holes  22   a  and  22   b  has a narrower end at the Z 1  side. 
     Each of the signal contacts  14   a ,  14   b ,  114   a , and  114   b  has an L-shape. Each of the upper ends  14   a - 1 ,  14   b - 1 ,  114   a - 1 , and  114   b - 1  of the signal contacts  14   a ,  14   b ,  114   a , and  114   b  is bent in an angular shape (see  FIG. 6A ), and each of the lower ends  14   a - 2 ,  14   b - 2 ,  114   a - 2 , and  114   b - 2  is bent at the right angle (the upper ends  114   b - 1  and the lower ends  114   b - 2  are not shown). The upper ends  14   a - 1 ,  14   b - 1 ,  114   a - 1 , and  114   b - 1  are to be connected to a mating connector, and will be hereinafter referred to as connector contact parts. The lower ends  14   a - 2 ,  14   b - 2 , and  114   a - 2 , and  114   b - 2  are to form the contact of the substrate side, and will be hereinafter referred to as substrate contact parts. 
     The signal contacts  14   a  and  14   b , and the signal contacts  114   a  and  114   b , are set as pairs of signal contacts. Each pair of signal contacts  14   a  and  14   b , and signal contacts  114   a  and  114   b , is inserted into each corresponding pair of holes  22   a  and  22   b  from the Z 2  side. The upper ends  14   a - 1 ,  14   b - 1 ,  114   a - 1 , and  114   b - 1  stand along the side walls of the corresponding holes  22   a  and  22   b . The lower ends  14   a - 2  and  14   b - 2  are bent at the bottom end of the housing  12 , and extend in the direction of Y 2 , i.e., extend in parallel with one another from a longitudinal side wall  12   a  of the housing  12 . The lower ends  114   a - 2  and  114   b - 2  of the signal contacts  114   a  and  114   b  are bent at the bottom end of the housing  12 , and extend in the direction of Y 1 , i.e., extend in parallel with one another from a longitudinal side wall  12   b  of the housing  12 . Accordingly, the signal contacts are arranged as multiple rows in the direction of X 1 -X 2 , and as two arrays in the direction of Y 1 -Y 2 . 
     As shown in  FIG. 3 , each of the ground contacts  16  has upper ends  16   a  branching apart in the direction of Y 1 -Y 2 , and the tops of the angular upper ends  16   a  are inclined toward each other. The lower ends  16   b  of each of the ground contacts  16  also branch apart in the direction of Y 1 -Y 2 , and are bent in the horizontal direction. The ground contacts  16  are array internal ground contacts that shield the neighboring pairs of signal contacts  14   a ,  14   b ,  114   a , and  141   b  from one another. The upper ends  16   a  of each of the ground contacts  16  protrude up to immediately below the narrow opening  20   a  of each corresponding slit  20  of the housing  12 . The lower ends  16   b  of each of the ground contacts  16  extend in both directions of Y 1  and Y 2 . A shielding layer  24  is provided on either of the longitudinal side walls  12   a  and  12   b  of the housing  12 . 
     The lower ends  14   a - 2 ,  14   b - 2 ,  114   a - 2 ,  114   b - 2 , and  16   b  of the signal contacts  14   a ,  14   b ,  114   a ,  114   b , and the ground contacts  16 , are joined to a pad (not shown) formed on a wiring substrate  26  (also referred to as the “printed circuit board” or simply as the “substrate”in this specification), and thus are connected to a printed circuit (not shown) formed on the substrate  26 . 
     The plug connector  28  includes an array of pairs of signal contacts  32   a  and  32   b , an array of pairs of signal contacts  132   a  and  132   b , array internal ground contacts  34 , and array intermediate ground contacts  36 , all of which are arranged in a housing  30  that is made of an insulating material and is formed longitudinally in the direction of X 1 -X 2  of  FIG. 2B . 
     The housing  30  has a concavity  38  formed longitudinally in the direction of X 1 -X 2 . As shown in  FIG. 5 , holes  40   a  and  40   b  are formed through the bottom wall  30   a , and slits  42  are longitudinally and transversely formed so as to partition each pair of holes  40   a  and  40   b  off the other pairs. Also, two slits  44  are formed along the inner surfaces of the side walls of the housing  30 . The arrangement of the holes  40   a  and  40   b  and the slits  42  corresponds to the arrangement of the holes  22   a  and  22   b  and the slits  18  and  20  of the jack connector  10 . 
     Each of the signal contacts  32   a ,  32   b ,  132   a , and  132   b  has an L-shape. Each one signal contact  32   a  is paired with one signal contact  32   b , and each one signal contact  132   a  is paired with one signal contact  132   b . Each pair of signal contacts  32   a  and  32   b , and signal contacts  132   a  and  132   b , is inserted into each corresponding pair of holes  40   a  and  40   b  from the Z 2  side. The upper ends  32   a - 1 ,  32   b - 1 ,  132   a - 1 , and  132   b - 1  of the signal contacts  32   a ,  32   b ,  132   a , and  132   b  stand within the concavity  38  (the upper ends  132   b - 1  are not shown). The lower ends  32   a - 2  and  32   b - 2  of the signal contacts  32   a  and  32   b  are bent at the bottom end of the housing  30 , and extend in parallel with one another from the side wall  30   b  on the Y 2  side. The lower ends  132   a - 2  and  132   b - 2  of the signal contacts  132   a  and  132   b  are bent at the bottom end of the housing  30 , and extend in parallel with one another from the side wall  30   c  on the Y 1  side (the lower ends  132   b - 2  are not shown). Accordingly, the signal contacts are arranged as multiple rows in the direction of X 1 -X 2 , and as two arrays in the direction of Y 1 -Y 2 . 
     As shown in  FIG. 4 , each of the array internal ground contacts  34  has a flat-panel shape with a step-like notch  34   a . Each of the array internal ground contacts  34  also has lower ends  34   b  that bend and extend toward both sides. The array intermediate ground contacts  36  has a flat-panel shape, with slits  36   a  being formed at predetermined intervals. 
     The array intermediate ground contact  36  is positioned in the center of the concavity  38  of the housing  30  in the direction of Y 1 -Y 2 . The slits  36   a  of the array intermediate ground contact  36  are engaged with the notches  34   a , so that the array internal ground contacts  34  are arranged perpendicularly to the array intermediate ground contact  36 . Accordingly, the array intermediate ground contact  36  is electrically connected to the array internal ground contacts  34 . Each of the array internal ground contacts  34  has the lower ends  34   b  extending outward from the bottom and the longitudinal side walls  30   b  and  30   c  of the housing  30  in the directions of Y 1  and Y 2 . 
     As can be seen from  FIG. 2B , the width W 1  of each of the array internal ground contacts  34  is greater than the distance L 1  between the two arrays of signal contacts  32   a  and  132   a  or signal contacts  32   b  and  132   b . Accordingly, each pair of signal contacts  32   a  and  32   b  and each pair of signal contacts  132   a  and  132   b  are shielded from the neighboring pairs of signal contacts  32   a  and  32   b  and the neighboring pairs of signal contacts  132   a  and  132   b  by the array internal ground contacts  34  in the direction of X 1 -X 2 . Likewise, the width W 2  of each divisional part of the array intermediate ground contact  36  divided by the array internal ground contacts  34  is greater than the distance L 2  between each two paired signal contacts  32   a  and  32   b  or signal contacts  132   a  and  132   b . Accordingly, each two neighboring pairs of signals contacts  32   a  and  32   b  and signal contacts  132   a  and  132   b  are completely shielded from each other by the array intermediate ground contact  36  in the direction of Y 1 -Y 2 . 
       FIG. 5  is a sectional view of the structure in which the signal contacts  32   a ,  32   b ,  132   a , and  132   b , the array internal ground contacts  34 , and the array intermediate ground contact  36  are arranged in the housing  30 . As can be seen from  FIG. 5 , a shielding layer  46  is provided on each inner surface of the longitudinal side walls  30   b  and  30   c  of the housing  30 , and the lower end  46   a  of each shielding layer  46  penetrates through the bottom wall  30   a  of the housing  30 . 
     The lower ends  32   a - 2 ,  32   b - 2 ,  132   a - 2 ,  132   b - 2 , and  34   b  of the signal contacts  32   a ,  32   b ,  132   a ,  132   b , and the array internal ground contacts  34  are joined to a pad (not shown) formed on a substrate  48 , and are thus connected to a printed circuit (not shown) formed on the substrate  48 . The lower end  46   a  of each shielding layer  46  is electrically connected to the ground (not shown) of the substrate  48 . 
     The connection mechanism of the above jack connector  10  and the plug connector  28  will be described below, with reference to  FIGS. 6A and 6B .  FIG. 6A  illustrates only one of the arrays of signal contacts.  FIG. 6B  illustrates the ground contacts. 
     When the plug connector  28  is to be connected to the jack connector  10 , the signal contacts  32   a  and  32   b  are inserted into the holes  22   a  and  22   b , while pushing the upper ends  14   a - 1  and  14   b - 1  of the signal contacts  14   a  and  14   b  in the direction of Y 2 . By virtue of the restoring force of the signal contacts  14   a  and  14   b , each signal contact  32   a  is brought into contact with each corresponding signal contact  14   a , and each signal contact  32   b  is brought into each corresponding signal contact  14   b.    
     As can be seen from  FIG. 6B , each of the array internal ground contacts  34  is inserted into each corresponding slit  20 , while pushing apart the upper ends  16   a  of each corresponding ground contact  16  in the directions of Y 1  and Y 2 . By virtue of the restoring force of the ground contacts  16 , each of the array internal ground contacts  34  is interposed between the upper ends  16   a  of each corresponding ground contact  16 . 
     In this manner, it can be made sure that the signal contacts  14   a , the signal contacts  14   b , and the ground contacts  16  are electrically connected to the signal contacts  32   a , the signal contacts  32   b , and the array internal ground contacts  34 , respectively. Likewise, it can be made sure that the signal contacts  114   a  and the signal contacts  114   b  are electrically connected to the signal contacts  132   a  and the signal contacts  132   b , respectively. The shielding layers  24  are slidably in contact with the shielding layers  46 , and are thus electrically connected to the shielding layers  46 . 
     The substrate  26  to which the jack connector  10  is mounted is connected to the substrate  48  to which the plug connector  28  is mounted, with the jack connector  10  and the plug connector  28  being interposed in between. In this connected state, one of the substrates  26  and  48  is stacked on the other. 
     Each pair of signal contacts  14   a  and  14   b ,  114   a  and  114   b ,  32   a  and  32   b , and  132   a  and  132   b , is designed for balanced transmission. If a positive signal is transmitted through the signal contacts  14   a ,  114   a ,  32   a , and  132   a , a negative signal is transmitted through the signal contacts  14   b ,  114   b ,  32   b , and  132   b . 
     With the above plug connector  28  and the jack connector  10  in accordance with the first embodiment of the present invention, the wiring design and the wiring operation for the substrates are simple, because the lengths of each pair of wires for connecting the multiple pairs of signal contacts to a terminal unit can be made uniform in a case where the terminal unit located perpendicularly to the longitudinal direction of the housing is to be connected to signal contacts to mount the connector device onto the substrates. Also, noise can be prevented between signals subject to balanced transmission through each pair of signal contacts, and the characteristic impedance can be stabilized even in a high-speed signal transmitting operation. 
     Also, since an array internal ground contact is provided between each two neighboring pairs of signal contacts in plug connector  28  and the jack connector  10 , crosstalk between each two neighboring pairs of signal contacts can be reduced. Particularly, the array internal ground contacts of the plug connector  28  are large enough to shield each pair of signal contacts from the neighboring pairs of signal contacts, and thus can effectively reduce crosstalk. 
     Further, with the array intermediate ground connector, the plug connector  28  can reduce crosstalk between the arrays of signal contacts. Also, with the shielding layers formed on the side walls of the housings, the plug connector  28  and the jack connector  10  can shield themselves from external electromagnetic waves. 
     Second Embodiment 
     Referring now to  FIGS. 7A through 9 , a connector in accordance with a second embodiment of the present invention will be described. 
     The connector in accordance with this embodiment includes a jack connector and a plug connector. Like the jack connector  10  and the plug connector  28  in the first embodiment, the jack connector and the plug connector are mounted on substrates, so as to connect multiple substrates. Although the connector in accordance with the first embodiment has a face-to-face connection mechanism in which the substrates are stacked on one another, the connector in accordance with the second embodiment described below has a horizontal connection mechanism in which the ends of substrates are connected to one another. 
     As shown in  FIGS. 7A and 7B , in a jack connector  50  and a plug connector  52 , a pair of signal contacts  54   a  and  54   b  (hereinafter referred to simply as the “contacts”) and a ground contact  58  (hereinafter referred to simply as the “contact”) form a group, and a pair of signal contacts  56   a  and  56   b  (hereinafter referred to simply as the “contacts”) and a ground contact  60  (hereinafter referred to simply as the “contact”) form a group. In each of the connectors  50  and  52 , multiple groups of signal contacts and ground contacts are aligned as one array. Each pair of signal contacts  54   a  and  54   b  and signal contacts  56   a  and  56   b  is designed for balanced transmission. If a positive signal is transmitted through the signal contacts  54   a  and  56   a , a negative signal is transmitted through the signal contacts  54   b  and  56   b.    
     The jack connector  50  will be described below in greater detail, followed by a detailed description of the plug connector  52 . 
     The jack connector  50  has a housing  62  that is made of an insulating material. Multiple grooves  64  are formed in the lower half of the housing  62  on the side of Z 2  in  FIG. 7A . The housing  62  has side walls on the sides of X 1 -X 2 , the upper wall on the side of Z 1 , and the back wall on the side of Y 1 , which are covered with a metal plate  66 . The metal plate  66  has protrusions  66   a  formed at the lower ends on both sides of X 1 -X 2 . The jack connector  50  does not require a bottom wall for the housing  62  on the side of Z 2 , and has a smaller height accordingly. 
     The contacts  54   a ,  54   b , and  58  of the jack connector  50  have uniform stick-like shapes, as shown in  FIGS. 8A and 8B . Each of the contacts  54   a ,  54   b , and  58  is provided with a step-like part formed in its mid section. Each of the top ends  54   a - 1 ,  54   b - 1 , and  58 - 1  of the contacts  54   a ,  54   b , and  58  on the side of Y 2  of  FIGS. 7A and 7B  and  FIG. 8A , has a protrusion A at the top facing inward. Also, a protrusion B extending in the direction of Z 1  is provided between the mid section and each of the top ends  54   a - 1 ,  54   b - 1 , and  58 - 1 . Each of the back ends  54   a - 2 ,  54   b - 2 , and  58 - 2  of the contacts has a tongue-like shape. 
     The protrusions B are engaged with concavities  68  formed in the upper walls of the grooves  64  of the housing  62 , so that the contacts  54   a ,  54   b , and  58  are fixed to the housing  62 . As there is no need to have the back wall  62   a  used for fixing the contacts  54   a ,  54   b , and  58 , the back wall  62   a  is made thin. As a result, the depth W 3  of the jack connector  50  is smaller (see  FIG. 9 ). In the connected state with the plug connector  52  that will be described later, the contacts  54   a ,  54   b , and  58  are fixed to the housing  62  through the engagement of the protrusions B extending in the direction (of Z 1 ) perpendicular to the connecting direction (Y 1 -Y 2 ) of the contacts  54   a ,  54   b , and  58  with the concavities  68 . In this structure, the contacts  54   a ,  54   b , and  58  cannot be pulled off, when the plug connector  52  is attached to or detached from the jack connector  50 . 
     The groups each consisting of a pair of signal contacts  54   a  and  54   b  and one ground contact  58  are set in the grooves  64  of the housing  62 . 
     A substrate  70  onto which the jack connector  50  is to be mounted has a protruding part  72  in the mid section on the side of Y 2 , as shown in  FIG. 7A . A wide pad (pattern)  74  is formed on the Y 1  side of the protruding part  72 . A pair of pads  76  is formed on both X 1 -X 2  sides of the pad  74 , and multiple pads  78  are arranged on the Y 1  side of the pad  74 . 
     The jack connector  50  is placed on the substrate  70 , and the protrusions  66   a  of the metal plate  66  are joined to the pads  76 , so that the metal plate  66  and the housing  62  held by the metal plate  66  are fixed to the substrate  70 . Meanwhile, the back ends  54   a - 2 ,  54   b - 2 , and  58 - 2  of the contacts  54   a ,  54   b , and  58  of the jack connector  50  are joined to the pads  78 , so that the contacts  54   a ,  54   b , and  58  are connected to a wiring pattern (not shown) formed on the substrate  70 . The other ends of the wires connected to the signal contacts  54   a  and  54   b  are connected to a terminal unit or the like (not shown) provided on the Y 1  side. The other ends of the wires connected to the ground contacts  58  are connected to a ground unit (not shown) provided on the Y 1  side. 
     The plug connector  52  has a housing  80  that is made of an insulating material. The housing  80  has a concavity  82  formed longitudinally in the direction of X 1 -X 2  of  FIG. 7B . The bottom wall  80   a  of the housing  80  has notches at both ends in the direction of X 1 -X 2 . The entire housing  80  is covered with a metal plate  84 , except the opening on the Y 1  side. The metal plate  84  has protrusions  84   a  at both lower ends in the direction of X 1 -X 2 . 
     The contacts  56   a ,  56   b , and  60  of the plug connector  52  have uniform stick-like shapes, as shown in  FIG. 8B . Each of the contacts  56   a ,  56   b , and  60  has a step-like part formed in its mid section. Each of the back ends  56   a - 2 ,  56   b - 2 , and  60 - 2  has a tongue-like shape. 
     The top ends  56   a - 2 ,  56   b - 2 , and  60 - 2  are pushed in the direction of Y 1  and penetrate through holes  80   c  formed in the back wall  80   b  of the housing  80 , so that the contacts  56   a ,  56   b , and  60  of the plug connector  52  are fixed to the housing  80 . The pairs of signal contacts  56   a  and  56   b  and the ground contacts  60  are alternately arranged on the bottom wall  80   a  of the housing  80 . 
     A substrate  86  onto which the plug connector  52  is to be mounted has a wide notch  88  in the mid section of the side of Y 1 . A pair of pads  90  is formed on both X 1 -X 2  sides of the notch  88 . Also, multiple pads  92  are arranged on the Y 2  side of the notch  88 . 
     The plug connector  52  is placed on the substrate  86 , and the protrusions  84   a  of the metal plate  84  are joined to the pads  90 , so that the metal plate  84  and the housing  80  held by the metal plate  84  are fixed to the substrate  86 . Meanwhile, the back ends  56   a - 1 ,  56   b - 1 , and  60 - 1  of the contacts  56   a ,  56   b , and  60  of the plug connector  52  are joined to the pads  92 , so that the contacts  56   a ,  56   b , and  60  are connected to a wiring pattern (not shown) formed on the substrate  86 . The other ends of the wires connected to the signal contacts  56   a  and  56   b  are connected to a terminal unit or the like (not shown) provided on the Y 2  side. The other ends of the wires connected to the ground contacts  60  are connected to a ground unit (not shown) provided on the Y 2  side. 
     The connection mechanism of the above jack connector  50  and the plug connector  52  will be described below, with reference to  FIGS. 8A and 8B  and  FIG. 9 . 
     The protruding part  72  of the substrate  70  onto which the jack connector  50  is mounted is engaged with the notch  88  of the substrate  86  onto which the plug connector  52  is mounted, so that the plug connector  52  is connected to the jack connector  50 . Here, the upper surfaces of the contacts  56   a ,  56   b , and  60  are slid along the contacts  54   a ,  54   b , and  58 , with the bottom wall  80   a  of the plug connector  52  being sandwiched between the pad  74  and the contacts  54   a ,  54   b , and  58  of the jack connector  50 . By doing so, the protrusions A are pushed in the direction of Z 1 , and, by virtue of the restoring force of the top ends  54   a - 1 ,  54   b - 1 , and  58 - 1  of the contacts  54   a ,  54   b , and  58 , the contacts  56   a ,  56   b , and  60  are brought into close contact with the contacts  54   a ,  54   b , and  58 . The signal contacts  54   a , the signal contacts  54   b , and the ground contacts  58  are thus electrically connected to the signal contacts  56   a , the signal contacts  56   b , and the ground contacts  60 , respectively. Meanwhile, the metal plate  84  under the lower surface of the bottom wall  80   a  of the plug connector  52  is brought into contact with the pad  74  of the jack connector  50 , so that the metal plate  84  is electrically connected to the pad  74 . 
     In this manner, the substrate  70  to which the jack connector  50  is mounted and the substrate  86  to which the plug connector  52  is mounted are horizontally connected to each other via the jack connector  50  and the plug connector  52 . 
     With the above plug connector  52  and the jack connector  50  in accordance with the second embodiment of the present invention, the wiring design and the wiring operation are simplified, because the lengths of the wires that connect the pairs of signal contacts and a terminal unit or the like can be made uniform in a case where the terminal unit or the like located perpendicularly to the longitudinal direction of the housing is to be connected to the signal contacts so as to mount the connectors onto the substrates. Also, noise can be prevented in signals subject to balance transmission through each pair of signal contacts, and the characteristic impedance can be stabilized even in a high-speed signal transmitting operation. 
     Furthermore, as the metal plates that serve as shielding layers are provided on the exteriors of the housings, the plug connector  52  and the jack connector  50  can shield themselves from external electromagnetic waves. When the plug connector  52  is attached to or detached from the jack connector  50 , the contact force of the contacts of both connectors expands the housings, but the expansion of the housings can be restricted by the metal plates covering the housings. 
     Since the attachment of the plug connector  52  to the substrate  86  and the attachment of the jack connector  50  to the substrate  70  are carried out only through the protrusions of the metal plates and the back ends of the contacts, the number of soldered points is small, and the soldering operation can be efficiently carried out. Also, as the contacts are formed like sticks by plate-stamping with excellent dimensional precision, the contact surfaces have excellent plane-dimensional precision. 
     Third Embodiment 
     A connector in accordance with a third embodiment of the present invention will be next described. 
       FIGS. 10A through 10D  illustrate a plug connector  210  in accordance with the third embodiment. More specifically,  FIG. 10A  is a perspective view of the connector  210 ,  FIG. 10B  is a partially cutaway perspective view of the connector  210 ,  FIG. 10C  is a sectional view of the connector  210  taken along the line X C  of  FIG. 10B , and  FIG. 10D  is a sectional view of the connector  210  taken along the line X D  of  FIG. 10B . 
     The connector  210  includes a housing  211  having a concavity  212 . The housing  211  is made of an insulating material such as polyester or LCP (Liquid Crystal Polymer) resin. A contact supporting member  213  extending in the longitudinal direction of the connector  210  is provided in the concavity  212 . The contact supporting member  213  may be integrally formed with the housing  211 , and is shaped like a flat panel. The contact supporting member  213  has two planes facing each other, and signal contacts  214   a ,  214   b ,  215   a , and  215   b  of uniform lengths are arranged on the two planes. Each one signal contact  214   a  is paired with one signal contact  214   b , and each pair of signal contacts  214   a  and  214   b  is designed for balanced transmission of signals at a speed of 1 Gbit/s or higher. Accordingly, each pair of signal contacts  214   a  and  214   b  transmits signals of the same sizes and the opposite polarities. The pairs of signal contacts are adjacent to one another over the entire length, and are uniformly arranged. Also, the pairs of signal contacts  214   a  and  214   b  are in parallel with one another over the entire length, and are aligned at uniform intervals. Accordingly, excellent coupling can be established over the entire length of each of the signal contacts, unlike the prior art in which coupling cannot be established among some of the signal contacts. 
     The multiple pairs of signal contacts  214   a  and  214   b  are arranged as one array at uniform intervals in the longitudinal direction of the housing  211 . Likewise, each one signal contact  215   a  is paired with one signal contact  215   b , and each pair of signal contacts  215   a  and  215   b  is designed for balanced transmission. Multiple pairs of signal contacts  215   a  and  215   b  are arranged in parallel with one another on the other plane of the contact supporting member  213 . In other words, the signal contacts  215   a  and  215   b  are arranged as one array at uniform intervals in the longitudinal direction of the housing  211 . Accordingly, the connector  210  has a two-array structure that includes the array of the signal contacts  214   a  and  214   b  and the array of the signal contacts  215   a  and  215   b.    
     The signal contacts  214   a ,  214   b ,  215   a , and  215   b  are made of a single material, and have thin and long shapes (pin-like shapes) of uniform lengths. For instance, the signal contacts  214   a ,  214   b ,  215   a , and  215   b  can be formed by stamping out a gold-plated flat plate of a copper alloy and then bending the stampedout parts. 
     Rectangular holes  223  are formed in the contact supporting member  213  and the bottom part of the housing  211 , and ground contacts  216  are arranged in the rectangular holes  223 . The ground contacts  216  divide the array of the signal contacts  214   a  and  214   b  into multiple pairs of signal contacts, and also divide the array of the signal contacts  215   a  and  215   b  into multiple pairs of signal contacts. Accordingly, between each two neighboring ground contacts  216 , there exist a pair of signal contacts  214   a  and  214   b  of one array and a pair of signal contacts  215   a  and  215   b  of the other array. 
     As shown in  FIG. 10C , each of the signal contacts  214   a  has a connector contact part  214   a - 1  to be connected to the corresponding contact of a mating connector, and a substrate contact part  214   a - 2  formed integrally with the connector contact part  214   a - 1 . Each connector contact part  214   a - 1  penetrates through each corresponding hole  221  formed in the housing  211 , and extends along one of the two planes of the contact supporting member  213 . Each substrate contact part  214   a - 2  is bent at approximately 90 degrees with respect to each corresponding connector contact part  214   a - 1 , and extends in such a manner as to be connected to a connecting terminal such as a pad provided on a mounting surface of a printed circuit board (not shown) Each of the contacts  215   a  on the opposite side of the contact supporting member  213  from the contacts  214   a  also has a connector contact part  215   a - 1  to be connected to the corresponding contact of a mating connector, and a substrate contact part  215   a - 2  formed integrally with the connector contact part  215   a - 1 . Each connector contact part  215   a - 1  penetrates through each corresponding hole  222  formed in the housing  211 , and extends along the other plane of the contact supporting member  213 . Each substrate contact part  215   a - 2  is bent at approximately 90 degrees with respect to each corresponding connector contact part  215   a - 1 , and extends in such a manner as to be connected to a connection terminal such as a pad provided on a mounting surface of a printed circuit board. The substrate contacts  214   a - 2  and  215   a - 2  extend in the opposite directions. The signal contacts  214   b  are formed in the same manner as the signal contacts  214   a , and the signal contacts  215   b  are formed in the same manner as the signal contacts  215   a . Accordingly, each pair of substrate contact parts  214   a - 2  and  214   b - 2  extends in a first direction (from one side of the housing  211 ), while each pair of substrate contact parts  215   a - 2  and  215   b - 2  extends in a second direction (from the other side of the housing  211 ) that is the opposite of the first direction. 
     As shown in  FIG. 10D , each of the ground contacts  216  has two substrate contact parts  216 - 1  and  216 - 2 , and a plate-like part  216 - 3  formed integrally with the two substrate contact parts  216 - 1  and  216 - 2 . The ground contacts  216  are arranged in both two arrays of signal contacts. The plate-like part  216 - 3  of each ground contact  216  penetrates through the corresponding rectangular hole  223  formed in the housing  211  and the contact supporting member  213 , and extends in the vertical direction. The top of each plate-like part  216 - 3  protrudes from the upper surface of the contact supporting member  213 . Accordingly, the ground contacts  216  may be taller than or as tall as the signal contacts  214   a ,  214   b ,  215   a , and  215   b . To effectively shield each pair of signal contacts from the neighboring pairs, the width of each plate-like part  216 - 3  is greater than the distance between each two adjacent signal contacts  214   a  ( 214   b ) and  215   a  ( 215   b ). The substrate contact part  216 - 1  of each ground contact  216  extends in such a manner as to be connected to a connection terminal such as a pad provided on a mounting surface. The substrate contact parts  216 - 1  are on the same level (an even level without a step) as the substrate contact parts  214   a - 2  of the signal contacts  214   a , and also extend in the same direction as the substrate contact parts  214   a - 2  of the signal contacts  214   a . The other substrate contact part  216 - 2  of each ground contact  216  is formed in the same manner as the above. The substrate contact parts  216 - 1  and  216 - 2  extend in the opposite directions. 
     In this structure, an array of multiple pairs of substrate contact parts  214   a - 2  and  214   b - 2 , with a substrate ground contact part  216 - 1  being interposed between each two neighboring pairs, and an array of multiple pairs of substrate contact parts  215   a - 2  and  215   b - 2 , with a substrate ground contact part  216 - 2  being interposed between each two neighboring pairs, are formed on the side of a wiring substrate. The two arrays of substrate contact parts exist on the same level, and extend in the opposite directions. The substrate contact parts  214   a - 2 ,  214   b - 2 , and the substrate ground contact parts  216 - 1 , are aligned at uniform intervals. 
     Protruding parts  224  are formed at the left and right sides of the housing  211 , and cylindrical fixing members  225  are inserted into holes formed in the protruding parts  224 . Each of the fixing members  225  is inserted into each corresponding through hole formed in the wiring substrate, and is then fixed by soldering. Thus, the connector  210  can be mounted and fixed to the wiring substrate. 
     The substrate contact parts  214   a - 2  and  214   b - 2  in each pair extend in parallel with each other and have the same lengths, so that signals can travel in balanced transmission in the same phase on the wiring substrate. Likewise, the substrate contact parts  215   a - 2  and  215   b - 2  in each pair expend in parallel with each other and have the same lengths, so that signals can be transmitted in the balanced state in the same phase on the wiring substrate. As a result, noise that was caused by a phase difference in the prior art can be prevented, and the characteristic impedance can be stabilized. Also, the substrate contact parts  214   a - 2  and  214   b - 2  are adjacent to one another, and the substrate contact parts  215   a - 2  and  215   b - 2  are also adjacent to one another. Thus, the lengths of each pair of wires on the wiring substrate can be easily made uniform, and the wiring design and the wiring operation for the wiring substrate can be readily simplified. Furthermore, even in the two-array structure, the pairs of signal contacts are adjacent to one another over the entire length. Accordingly, excellent high-density balanced transmission can be realized. 
     The pairs of signal contacts adjacent to one another in the longitudinal direction of the connector  210  are electrically shielded from one another by the ground contacts  216 , and accordingly, there is no interference between each two neighboring pairs of signal contacts in each array. Meanwhile, each pair of signal contacts  214   a  and  214   b  faces each corresponding pair of signal contacts  215   a  and  215   b  via the contact supporting member  213  made of an insulating material, and any shielding member like the array intermediate ground contact  36  of the first embodiment is not employed in this embodiment. Accordingly, compared with the first embodiment, there is a greater possibility that phase difference is caused between the arrays of signal contacts facing each other via the contact supporting member  213 , and noise is then generated. However, chances are that there will be no problems in practice, as long as the distance between each pair of signal contacts  214   a  and  214   b  and the distance between each pair of signal contacts  215   a  and  215   b  are shorter than the diagonal distance between each two opposite signal contacts  214   a  and  215   b  and the diagonal distance between each two opposite signal contacts  214   b  and  215   a , respectively. Since a shielding member like the array intermediate ground contact  36  of the first embodiment is not employed, this embodiment has an advantage of reducing the production costs of the connector requiring a smaller number of components. 
     Referring next to  FIGS. 11A through 11D , a jack connector  230  in accordance with the third embodiment of the present invention will be described.  FIG. 11A  is a perspective view of the connector  230 ,  FIG. 11B  is a partially cutaway perspective view of the connector  230 ,  FIG. 11C  is a sectional view of the connector  230  taken along the line XI C  of  FIG. 11B , and  FIG. 11D  is a sectional view of the connector  230  taken along the line XI D  of  FIG. 11B . The jack connector  230  is to be paired with the plug connector  210 . 
     The connector  230  includes a housing  231  having a convexity  232 . The housing  231  is made of an insulating material such as polyester or liquid crystal polymer resin. The convexity  232  extends in the longitudinal direction of the connector  230 , and has a concavity  233 . The contact supporting member  213  of the connector  210  is to be inserted into the concavity  233 . In the concavity  233 , two arrays of signal contacts and ground contacts are arranged. One of the arrays includes signal contacts  234   a  and  234   b  of uniform lengths, and the other array includes signal contacts  235   a  and  235   b  having the same lengths as the signal contacts  234   a  and  234   b . Each one signal contact  234   a  is paired with one signal contact  234   b , and each pair of signal contacts  234   a  and  234   b  is designed for balanced transmission of signals at a speed of 1 Gbit/s or higher. 
     The pairs of signal contacts  234   a  and  234   b  are adjacent to one another over the entire length, and are uniformly arranged. Also, the pairs of signal contacts  234   a  and  234   b  extend in parallel with one another over the entire length, and are aligned at uniform intervals. Accordingly, excellent coupling can be established over the entire length of the signal contacts  234   a  and  234   b.    
     The multiple pairs of signal contacts  234   a  and  234   b  are arranged in parallel with one another at intervals, and constitute one of the two arrays. Likewise, each one signal contact  235   a  is paired with one signal contact  235   b , and each pair of signal contacts  235   a  and  235   b  is designed for balanced transmission. The multiple pairs of signal contacts  235   a  and  235   b  are arranged in parallel with one another at intervals, and constitute the other array. Accordingly, the connector  230  includes the signal contacts  234   a ,  234   b ,  235   a , and  235   b  that are arranged in the two arrays. 
     The signal contacts  234   a ,  234   b ,  235   a , and  235   b  are made of a single material, and have thin and long shapes (pin-like shapes) of uniform lengths. For instance, the signal contacts  234   a ,  234   b ,  235   a , and  235   b  can be formed by stamping out a gold-plated flat plate of a copper alloy and then bending the stamped-out parts. 
     Rectangular holes  245  are formed in the bottom part of the housing  231 , and ground contacts  236  are arranged in the rectangular holes  245 . The ground contacts  236  divide the array of the signal contacts  234   a  and  234   b  into multiple pairs of signal contacts, and also divide the array of the signal contacts  235   a  and  235   b  into multiple pairs of signal contacts. Accordingly, between each two neighboring ground contacts  236 , there exist a pair of signal contacts  234   a  and  234   b  of one array and a pair of signal contacts  235   a  and  235   b  of the other array. 
     As shown in  FIG. 11C , each of the signal contacts  234   a  is a single member that has a connector contact part  234   a - 1  to be connected to the corresponding connector contact part  214   a - 1  of the plug connector  210 , and a substrate contact part  234   a - 2 . Each connector contact part  234   a - 1  penetrates through each corresponding hole  241  formed in the housing  231 , and extends along the inside of the concavity  233 . With the connector  230  being mounted onto a wiring substrate, each connector contact part  234   a - 1  extends perpendicularly to the wiring substrate. Each substrate contact part  234   a - 2  is bent at approximately 90 degrees with respect to each corresponding connector contact part  234   a - 1 , and extends in such a manner as to be connected to a connecting terminal such as a pad provided on a mounting surface of a printed circuit board (not shown). Each of the contacts  235   a  facing the contacts  214   a  via a space also has a connector contact part  235   a - 1  to be connected to the corresponding connector contact  215   a - 1  of the plug connector  210 , and a substrate contact part  235   a - 2  formed integrally with the connector contact part  235   a - 1 . Each connector contact part  235   a - 1  penetrates through each corresponding hole  242  formed in the housing  231 , and extends along the inside of the concavity  233 . Each substrate contact part  235   a - 2  is bent at approximately 90 degrees with respect to each corresponding connector contact part  235   a - 1 , and extends in such a manner as to be connected to a connection terminal such as a pad provided on a mounting surface of a printed circuit board. The substrate contacts  234   a - 2  and  235   a - 2  extend in the opposite directions. The signal contacts  234   b  are formed in the same manner as the signal contacts  234   a , and the signal contacts  235   b  are formed in the same manner as the signal contacts  235   a . Each of the connector contact parts  234   a - 1 ,  234   b - 1 ,  235   a - 1 , and  235   b - 1  has an inward protrusion like the protrusion A, and is tilted inward so as to provide spring tension. When the plug connector  210  is attached to the jack connector  230 , the connector contact parts  214   a - 1 ,  214   b - 1   215   a - 1 , and  215   b - 1  of the plug connector  210  are engaged with the corresponding connector contact parts  234   a - 1 ,  234   b - 1 ,  235   a - 1 , and  235   b - 1 , and the inward protrusions pushes outward the connector contact parts  214   a - 1 ,  214   b - 1   215   a - 1 , and  215   b - 1 . By virtue of the spring restoring force of the connector contact parts  234   a - 1 ,  234   b - 1 ,  235   a - 1 , and  235   b - 1 , electric connection can be surely established. 
     As shown in  FIG. 1D , each of the ground contacts  236  has two substrate contact parts  236 - 1  and  236 - 2 , two connector contact parts  236 - 3  and  236 - 4 , and a base part  236 - 5 . Each of the contact parts  236 - 1  through  236 - 4  and the base parts  236 - 5  is a single member that may be formed by stamping out a gold-plated flat panel of a copper alloy and then bending the stamped-out part. Each of the connector contact parts  236 - 3  and  236 - 4  penetrates through each corresponding hole  241  formed in the housing  231 , and extends along the inside of the concavity  233 . Each two adjacent connector contact parts  236 - 3  and  236 - 4  face each other via a space. Each of the connector contact parts  236 - 3  and  346 - 4  has an inward protrusion, and is tilted inward so as to provide spring tension. In other words, the connector contact parts  236 - 3  and  236 - 4  are the same as the connector contact parts  234   a - 1  and  235   a - 1  shown in  FIG. 11C . When the plug connector  210  is attached to the jack connector  230 , the protrusions of the connector contact parts  236 - 3  and  236 - 4  are engaged with the corresponding ground contacts  216  of the plug connector  210 , and pushes these connector contact parts outward. Thus, electric connection can be surely established by virtue of the restoring force. The substrate contact parts  236 - 1  and  236 - 2  are bent outward at approximately 90 degrees with respect to the base parts  236 - 5 , and extend in the opposite directions. 
     In this structure, an array of multiple pairs of substrate contact parts  234   a - 2  and  234   b - 2 , with a substrate ground contact part  236 - 1  being interposed between each two neighboring pairs, and an array of multiple pairs of substrate contact parts  235   a - 2  and  235   b - 2 , with a substrate ground contact part  236 - 2  being interposed between each two neighboring pairs, are formed on the side of the wiring substrate. The two arrays of substrate contact parts exist on the same level, and extend in the opposite directions. The substrate contact parts  234   a - 2 ,  234   b - 2 , and the substrate ground contact parts  236 - 1 , are aligned at uniform intervals, and so are the substrate contact parts  235   a - 2 ,  235   b - 2 , and the substrate ground contact parts  236 - 2 . 
     The substrate contact parts  234   a - 2  and  234   b - 2  in each pair extend in parallel with each other and have the same lengths, so that signals can be transmitted in the balanced state in the same phase on the wiring substrate. Likewise, the substrate contact parts  235   a - 2  and  235   b - 2  in each pair expend in parallel with each other and have the same lengths, so that signals can be balanced-transmitted in the same phase on the wiring substrate. As a result, noise that was caused by a phase difference in the prior art can be prevented, and the characteristic impedance can be stabilized. Also, the substrate contact parts  234   a - 2  and  234   b - 2  are adjacent to one another, and the substrate contact parts  235   a - 2  and  235   b - 2  are also adjacent to one another. Thus, the lengths of each pair of wires on the wiring substrate can be easily made uniform, and the wiring design and the wiring operation for the wiring substrate can be readily simplified. Furthermore, even in the two-array structure, the pairs of signal contacts are adjacent to one another over the entire length. Accordingly, excellent high-density balanced transmission can be realized. 
     When the jack connector  230  and the plug connector  210  are connected to each other, the ground contacts  216  of the plug connector  210  are inserted between the pairs of signal contacts adjacent to one another in the array direction of the jack connector  230 . Thus, the pairs of signal contacts adjacent to one another in the array direction of the jack connector  230  can be effectively shielded from one another. 
     Fourth Embodiment 
     A connector in accordance with a fourth embodiment of the present invention will be described below. 
       FIGS. 12A through 12D  illustrate a jack connector  250  in accordance with the fourth embodiment. More specifically,  FIG. 12A  is a perspective view of the connector  250 ,  FIG. 12B  is a partially cutaway perspective view of the connector  250 ,  FIG. 12C  is a sectional view of the connector  250  taken along the line XII C  of  FIG. 12B , and  FIG. 12D  is a sectional view of the connector  250  taken along the line XII D  of  FIG. 12B . The jack connector  250  is to be paired with the plug connector  210 . 
     The connector  250  includes a housing  251  having a convexity  252 . The housing  251  is made of an insulating material such as polyester or liquid crystal polymer resin. The convexity  252  extends in the longitudinal direction of the connector  250 , and has a concavity  253 . The contact supporting member  213  of the connector  210  is to be inserted into the concavity  253 . In the concavity  253 , two arrays of signal contacts and ground contacts are arranged. One of the arrays includes signal contacts  264   a  and  264   b , and the other array includes signal contacts  265   a  and  265   b . Each one signal contact  264   a  is paired with one signal contact  264   b , and each pair of signal contacts  264   a  and  264   b  is designed for balanced transmission of signals at a speed of 1 Gbit/s or higher. Multiple pairs of these signal contacts  264   a  and  264   b  are arranged in parallel with one another at intervals, and form one of the arrays. Likewise, each one signal contact  265   a  is paired with one signal contact  265   b , and each pair of signal contacts  265   a  and  265   b  is designed for balanced transmission. 
     The pairs of signal contacts  264   a  and  264   b  are adjacent to one another over the entire length (or are uniformly arranged). Also, the pairs of signal contacts  264   a  and  264   b  extend in parallel with one another over the entire length (or are aligned at uniform intervals). This arrangement of signal contacts greatly differs from the prior art. 
     The multiple pairs of signal contacts  265   a  and  265   b  are arranged in parallel with one another at intervals, and constitute the other array. Accordingly, the connector  250  includes the signal contacts  264   a ,  264   b ,  265   a , and  265   b  that are arranged in the two arrays. 
     The signal contacts  264   a  and  264   b  are individual members that have thin and long shapes (pin-like shapes) of uniform lengths, and may be formed by stamping out a gold-plated flat plate of a copper alloy and then bending the stamped-out parts. The signal contacts  265   a  and  265   b  are formed in the same manner. However, the lengths of the signal contacts  265   a  and  265   b  may be the same as the lengths of the signal contacts  264   a  and  264   b , or may be different from the lengths of the signal contacts  264   a  and  264   b , depending on the angle of the bend at the mid section of each signal contact. 
     Rectangular holes are formed in the housing  251 , and ground contacts  266  are arranged in the rectangular holes. The ground contacts  266  divide the array of the signal contacts  264   a  and  264   b  into multiple pairs of signal contacts, and also divide the array of the signal contacts  265   a  and  265   b  into multiple pairs of signal contacts. Accordingly, between each two neighboring ground contacts  266 , there exist a pair of signal contacts  264   a  and  264   b  of one array and a pair of signal contacts  265   a  and  265   b  of the other array. 
     As shown in  FIG. 12C , each of the signal contacts  264   a  is a single member that has a connector contact part  264   a - 1  to be connected to the corresponding connector contact part  214   a - 1  of the plug connector  210 , a substrate contact part  264   a - 2 , and a mid-section part  264 - 3  existing between the connector contact part  264   a - 1  and the substrate contact part  264   a - 2 . Each connector contact part  264   a - 1  penetrates through each corresponding hole formed in the housing  251 , and extends along the inside of the concavity  253 . With the connector  250  being mounted onto a wiring substrate, each connector contact part  264   a - 1  extends in parallel with the wiring substrate. Each substrate contact part  264   a - 2  extends in such a manner as to be connected to a connecting terminal such as a pad provided on a mounting surface of a printed circuit board (not shown). Each of the contacts  265   a  facing the contacts  264   a  via a space is also a single member that has a connector contact part  265   a - 1  to be connected to the corresponding connector contact  215   a - 1  of the plug connector  210 , a substrate contact part  235   a - 2 , and a mid-section part  265   a - 3  to connect the connector contact part  265   a - 1  and the substrate contact part  265   a - 2 . Each connector contact part  265   a - 1  penetrates through each corresponding hole formed in the housing  251 , and extends along the inside of the concavity  253 . Each substrate contact part  265   a - 2  extends in such a manner as to be connected to a connection terminal such as a pad provided on a mounting surface of a printed circuit board. The substrate contacts  264   a - 2  and  265   a - 2  extend in the opposite directions. The signal contacts  264   b  are formed in the same manner as the signal contacts  264   a , and the signal contacts  265   b  are formed in the same manner as the signal contacts  265   a.    
     As a result, the connector contact parts  264   a - 1 ,  264   b - 1 ,  265   a - 1 , and  265   b - 1 , extend in the same direction as the substrate contact parts  264   a - 2  and  264   b - 2 , while the substrate contacts  265   a - 2  and  265   b - 2  extend in the opposite direction from the substrate contact parts  264   a - 2  and  264   b - 2 . 
     Each of the connector contact parts  264   a - 1 ,  264   b - 1 ,  265   a - 1 , and  265   b - 1  has an inward protrusion, and is tilted inward so as to provide spring tension. When the plug connector  210  is attached to the jack connector  250 , the connector contact parts  214   a - 1 ,  214   b - 1   215   a - 1 , and  215   b - 1  of the plug connector  210  are engaged with the corresponding connector contact parts  264   a - 1 ,  264   b - 1 ,  265   a - 1 , and  265   b - 1 , and the inward protrusions pushes outward the connector contact parts  214   a - 1 ,  214   b - 1   215   a - 1 , and  215   b - 1 . By virtue of the spring restoring force of the connector contact parts  234   a - 1 ,  234   b - 1 ,  235   a - 1 , and  235   b - 1 , electric connection can be surely established. 
     As shown in  FIG. 12D , each of the ground contacts  266  has two substrate contact parts  266 - 1  and  266 - 2 , two connector contact parts  266 - 3  and  266 - 4 , and a base part  266 - 5 . Each of the contact parts  266 - 1  through  266 - 4  and the base parts  266 - 5  is a single member that may be formed by stamping out a gold-plated flat panel of a copper alloy and then bending the stamped-out part. Each of the connector contact parts  266 - 3  and  266 - 4  penetrates through each corresponding hole formed in the housing  251 , and extends along the inside of the concavity  253 . Each two adjacent connector contact parts  266 - 3  and  266 - 4  face each other via a space. Each of the connector contact parts  266 - 3  and  366 - 4  has an inward protrusion, and is tilted inward so as to provide spring tension. In other words, the connector contact parts  266 - 3  and  266 - 4  are the same as the connector contact parts  264   a - 1  and  265   a - 1  shown in  FIG. 12C . When the plug connector  210  is attached to the jack connector  250 , the protrusions of the connector contact parts  266 - 3  and  266 - 4  are engaged with the corresponding ground contacts  216  of the plug connector  210 , and pushes these connector contact parts outward. Thus, electric connection can be surely established. The substrate contact parts  266 - 1  and  266 - 2  are bent outward at approximately 90 degrees with respect to the base parts  266 - 5 , and extend in the opposite directions. In this structure, an array of multiple pairs of substrate contact parts  264   a - 2  and  264   b - 2 , with a substrate ground contact part  266 - 1  being interposed between each two neighboring pairs, and an array of multiple pairs of substrate contact parts  265   a - 2  and  265   b - 2 , with a substrate ground contact part  266 - 2  being interposed between each two neighboring pairs, are formed on the side of the wiring substrate. The two arrays of substrate contact parts exist on the same plane (a mounting surface), and extend in the opposite directions. 
     The substrate contact parts  264   a - 2  and  264   b - 2  in each pair extend in parallel with each other and have the same lengths, so that signals can be balanced-transmitted in the same phase. Likewise, the substrate contact parts  265   a - 2  and  265   b - 2  in each pair expend in parallel with each other and have the same lengths, so that signals can be transmitted in the same phase under the balanced condition. As a result, noise that was caused by a phase difference in the prior art can be prevented, and the characteristic impedance can be stabilized. Also, the substrate contact parts  264   a - 2  and  264   b - 2  are adjacent to one another at uniform intervals, and the substrate contact parts  235   a - 2  and  235   b - 2  are also adjacent to one another at uniform intervals. Thus, the lengths of each pair of wires on the wiring substrate can be easily made uniform, and the wiring design and the wiring operation for the wiring substrate can be readily simplified. 
     When the jack connector  250  and the plug connector  210  are connected to each other, the ground contacts  216  of the plug connector  210  are inserted between the pairs of signal contacts adjacent to one another in the array direction of the jack connector  250 . Thus, the pairs of signal contacts adjacent to one another in the array direction of the jack connector  250  can be effectively shielded from one another. 
     Fifth Embodiment 
     A connector in accordance with a fifth embodiment of the present invention will be now described below. 
       FIGS. 13A through 13D  illustrate a plug connector  270  in accordance with the fifth embodiment. More specifically,  FIG. 13A  is a perspective view of the connector  270 ,  FIG. 13B  is a partially cutaway perspective view of the connector  270 ,  FIG. 13C  is a sectional view of the connector  270  taken along the line XIII C  of  FIG. 13B , and  FIG. 13D  is a sectional view of the connector  270  taken along the line XIII D  of  FIG. 13B . Although the connectors of the foregoing embodiments are to be mounted onto a mounting surface of a wiring substrate, the connector  270  of the fifth embodiment is to be mounted to a wiring substrate, with the wiring substrate being interposed in the connector  270 . The substrate contact parts described later can be connected to connection terminals provided on two opposite planes of a wiring substrate. 
     The connector  270  includes a housing  271  having a concavity  272 . The housing  271  is made of an insulating material such as polyester or liquid crystal polymer resin. A contact supporting member  273  extending in the longitudinal direction of the connector  270  is provided in the concavity  272 . The contact supporting member  273  may be integrally formed with the housing  271 , and has a panel-like shape. The contact supporting member  273  has two facing planes, and signal contacts  274   a ,  274   b ,  275   a , and  275   b  are arranged on the two planes. Each one signal contact  274   a  is paired with one signal contact  274   b , and each pair of signal contacts  274   a  and  274   b  is designed for balance transmission of signals at a speed higher than  1  Gbit/s or higher. Accordingly, signals of the same sizes and the opposite polarities are transmitted through each pair of signal contacts  274   a  and  274   b.    
     The pairs of signal contacts  274   a  and  274   b  are adjacent to one another over the entire length, and are uniformly arranged. Also, the pairs of signal contacts  274   a  and  274   b  extend in parallel with one another over the entire length, and are aligned at uniform intervals. 
     The multiple pairs of signal contacts  274   a  and  274   b  are arranged in parallel with one another at intervals on one of the two planes of the contact supporting member  273 . Accordingly, the signal contacts  274   a  and  274   b  are aligned at intervals in one array in the longitudinal direction of the housing  271 . Likewise, each one signal contact  275   a  is paired with one signal contact  275   b , and each pair of signal contacts  275   a  and  275   b  is designed for balanced transmission. The multiple pairs of signal contacts  275   a  and  275   b  are arranged in parallel with one another at intervals on the other plane of the contact supporting member  273 . Accordingly, the signal contacts  275   a  and  275   b  are aligned in one array at intervals in the longitudinal direction of the housing  271 . Thus, the connector  270  has a two-array structure that includes the array of signal contacts  274   a  and  274   b  and the array of signal contacts  275   a  and  275   b.    
     The signal contacts  274   a ,  274   b ,  275   a , and  275   b , are individual members that have thin and long shapes of uniform lengths, and may be formed by stamping out a gold-plated flat plate of a copper alloy and then bending the stamped-out parts. 
     Rectangular holes are formed in the contact supporting member  273 , and ground contacts  276  are arranged in the rectangular holes. The ground contacts  276  divide the array of the signal contacts  274   a  and  274   b  into multiple pairs of signal contacts, and also divide the array of the signal contacts  275   a  and  275   b  into multiple pairs of signal contacts. Accordingly, between each two neighboring ground contacts  276 , there exist a pair of signal contacts  274   a  and  274   b  of one array and a pair of signal contacts  275   a  and  275   b  of the other array. 
     As shown in  FIG. 13C , each of the signal contacts  274   a  has a connector contact part  274   a - 1  to be connected to the jack connector  230  or  250 , and a substrate contact part  274   a - 2  that is integrally formed with the connector contact part  274   a - 1 . Likewise, each of the signal contacts  275   a  has a connector contact part  275   a - 1  to be connected to the jack connector  230  or  250 , and a substrate contact part  275   a - 2  that is integrally formed with the connector contact part  275   a - 1 . Each of the connector contact parts  274   a - 1  and  275   a - 1  penetrates through each corresponding hole formed in the housing  271 , and extends along the facing planes of the contact supporting member  273 . Each of the substrate contact parts  274   a - 2  and  275   a - 2  linearly and continuously extends from each corresponding one of the connector contact parts  274   a - 1  and  275   a - 1 . Also, the substrate contact parts  274   a - 2  and  275   a - 2  extend in the opposite direction from the connector contact parts  274   a - 1  and  275   a - 1 . Each two adjacent substrate contact parts  274   a - 2  and  275   a - 2  face each other via a space, and are slightly bent inward. The distance between each two adjacent substrate contact parts  274   a - 2  and  275   a - 2  is slightly shorter than the distance between each two adjacent connector contact parts  274   a - 1  and  275   a - 1 . A wiring substrate is inserted between the substrate contact parts  274   a - 2  and the substrate contact parts  275   a - 2 . The insides of the substrate contact parts  274   a - 2  and  275   a - 2  are engaged with the corresponding contact parts of a mating connector. The thickness of the wiring substrate is greater than the space between the substrate contact parts  274   a - 2  and the substrate contact parts  275   a - 2 . As a result, the substrate contact parts  274   a - 2  and the substrate contact parts  275   a - 2  are pushed outward. By virtue of the restoring force of the substrate contact parts  274   a - 2  and  275   a - 2 , electric contact with the connection electrodes provided on the two facing planes of the wiring substrate can be surely established. The signal contacts  274   b  and  275   b  have the same structures as the signal contacts  274   a  and  275   a , respectively. 
     As shown in  FIG. 13D , each of the ground contacts  276  has two substrate contact parts  276 - 1  and  276 - 2 , and a plate-like part  276 - 3  that is integrally formed with the substrate contact parts  276 - 1  and  276 - 2 . The ground contacts  276  are provided in both two arrays of signal contacts. Each of the plate-like parts  276 - 3  penetrates through each corresponding hole formed in the housing  271  and the contact supporting member  273 , and extends in the vertical direction. The top of each plate-like part  276 - 3  protrudes from the upper surface of the contact supporting member  273 . The width of each plate-like part  276 - 3  is greater than the distance between each two adjacent signal contacts  274   a  ( 274   b ) and  275   a  ( 275   b ). The substrate contact parts  276 - 1  and  276 - 2  of the ground contacts  276  extend in the same direction, and are slightly bent inward. Each two adjacent substrate contact parts  276 - 1  and  276 - 2  face each other via a space. The distance between each two adjacent substrate contact parts  276 - 1  and  276 - 2  is equal to the distance between each two adjacent substrate contact parts  274   a - 2  and  275   a - 2 . 
     In this structure, an array of multiple pairs of substrate contact parts  274   a - 2  and  274   b - 2 , with a substrate ground contact part  276 - 1  being interposed between each two neighboring pairs, and an array of multiple pairs of substrate contact parts  275   a - 2  and  275   b - 2 , with a substrate ground contact part  276 - 2  being interposed between each two neighboring pairs, are formed on the side of the wiring substrate. The two arrays of contact parts exist on different planes (the two opposite mounting surfaces), and extend in the same direction (from the bottom of the housing  271 ). 
     The substrate contact parts  274   a - 2  and  274   b - 2  in each pair extend in parallel with each other and have the same lengths, so that signals can be balanced-transmitted in the same phase on the wiring substrate. Likewise, the substrate contact parts  275   a - 2  and  275   b - 2  in each pair expend in parallel with each other and have the same lengths, so that signals can be balanced-transmitted in the same phase on the wiring substrate. As a result, noise that was caused by a phase difference in the prior art can be prevented, and the characteristic impedance can be stabilized. Also, the lengths of each pair of wires on the wiring substrate can be easily made uniform, and the wiring design and the wiring operation for the wiring substrate can be readily simplified. 
     Modifications 
     Modifications of the third embodiment, the fourth embodiment, and the fifth embodiments, will now be described below. In each of the following modifications, the structure for balanced-transmission high-speed signals of any of the third through fifth embodiments is combined with a structure for transmitting low-speed signals. 
       FIGS. 14A and 14B  illustrate a plug connector  210 A that is a modification of the plug connector  210  of the third embodiment. In the drawings, the same components as those in  FIGS. 10A through 10D  are denoted by the same reference numerals as those in  FIGS. 10A through 10D . Reference numeral  290  in  FIGS. 14A and 14B  indicates an area in which only signal contacts are provided. Hereinafter, the area  290  will be referred to as the “low-speed signal area”. In the low-speed signal area  290 , ground contacts  216  for dividing signal contacts into pairs are not provided, and signal contacts are successively arranged at intervals. The low-speed signal area  290  has a two-array structure including an array that continues to the array of signal contacts  214   a  and  214   b  for high-speed signal balanced-transmission, and an array that continues to the array of signal contacts  215   a  and  215   b . The signal contacts arranged in the low-speed signal area  290  each has the same structure as a signal contact  214   a  or the like. 
     Accordingly, the connector  210 A is a complex connector that realizes both high-speed signal balanced transmission and low-speed signal unbalanced transmission. The location of the low-speed signal area  290  is not limited to the location shown in the drawings, but may be at the left side or in the center of each drawing. Alternatively, multiple low-speed signal areas  290  may be arranged among high-speed signal areas. 
       FIGS. 15A and 15B  illustrate a jack connector  230 A that is a modification of the jack connector  230  of the third embodiment. In the drawings, the same components as those in  FIGS. 11A through 11D  are denoted by the same reference numerals as those in  FIGS. 11A through 11D . Reference numeral  292  in  FIGS. 15A and 15B  indicates an area in which only signal contacts are provided. Hereinafter, the area  292  will be referred to as the “low-speed signal area”. In the low-speed signal area  292 , ground contacts for dividing signal contacts into pairs are not provided, and signal contacts are successively arranged at intervals. The low-speed signal area  292  has a two-array structure including an array that continues to the array of signal contacts  234   a  and  234   b  for high-speed signal balanced transmission, and an array that continues to the array of signal contacts  235   a  and  235   b . Each of the signal contacts arranged in the low-speed signal area  292  has the same structure as a signal contact  234   a  or the like. 
     Accordingly, the connector  230 A is a complex connector through which both high-speed signals and low-speed signals can be efficiently transmitted. The location of the low-speed signal area  292  is not limited to the location shown in the drawings, but may be at the right side or in the center of each drawing. Alternatively, multiple low-speed signal areas  292  may be arranged among high-speed signal areas. 
       FIGS. 16A and 16B  illustrate a jack connector  250 A that is a modification of the jack connector  250  of the fourth embodiment. In the drawings, the same components as those in  FIGS. 12A through 12D  are denoted by the same reference numerals as those in  FIGS. 12A through 12D . Reference numeral  294  in  FIGS. 16A and 16B  indicates an area in which only signal contacts are provided. Hereinafter, the area  294  will be referred to as the “low-speed signal area”. In the low-speed signal area  294 , ground contacts for dividing signal contacts into pairs are not provided, and signal contacts are successively arranged at intervals. The low-speed signal area  294  has a two-array structure including an array that continues to the array of signal contacts  264   a  and  264   b  for high-speed signal balanced transmission, and an array that continues to the array of signal contacts  265   a  and  265   b . Each of the signal contacts arranged in the low-speed signal area  294  has the same structure as a signal contact  264   a  or the like. 
     Accordingly, the connector  250 A is a complex connector through which both high-speed signals and low-speed signals can be efficiently transmitted. The location of the low-speed signal area  294  is not limited to the location shown in the drawings, but may be at the right side or in the center of each drawing. Alternatively, multiple low-speed signal areas  294  may be arranged among high-speed signal areas. 
       FIGS. 17A and 17B  illustrate a plug connector  270 A that is a modification of the jack connector  270  of the fifth embodiment. In the drawings, the same components as those in  FIGS. 13A through 13D  are denoted by the same reference numerals as those in  FIGS. 13A through 13D . Reference numeral  296  in  FIGS. 17A and 17B  indicates an area in which only signal contacts are provided. Hereinafter, the area  296  will be referred to as the “low-speed signal area”. In the low-speed signal area  296 , ground contacts for dividing signal contacts into pairs are not provided, and signal contacts are successively arranged at intervals. The low-speed signal area  296  has a two-array structure including an array that continues to the array of signal contacts  274   a  and  274   b  for high-speed signal balanced transmission, and an array that continues to the array of signal contacts  275   a  and  275   b . Each of the signal contacts arranged in the low-speed signal area  296  has the same structure as a signal contact  274   a  or the like. 
     Accordingly, the connector  270 A is a complex connector through which both high-speed signals and low-speed signals can be efficiently transmitted. The location of the low-speed signal area  296  is not limited to the location shown in the drawings, but may be at the right side or in the center of each drawing. Alternatively, multiple low-speed signal areas  296  may be arranged among high-speed signal areas. 
     So far, the embodiments of the present invention and the modifications of the embodiments have been described. Any of the modifications of the third through fifth embodiments can be applied to the first and second embodiments, so as to form a complex connector. Also, the shielding metal plate employed in the first and second embodiments can be employed in any of the third through fifth embodiment and the modifications. Although the substrates shown in the drawings illustrating the first and second embodiments are not shown in the drawings illustrating the third through fifth embodiments and the modifications, any of the connectors of the third through fifth embodiments and the modifications can be mounted onto a substrate, and a wiring operation is thus carried out so as to form an electronic device.