Patent Publication Number: US-9425559-B2

Title: Electrical receptacle connector

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 103124184 and 103141533, filed in Taiwan, R.O.C. on 2014 Jul. 14 and 2014 Nov. 28, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The instant disclosure relates to an electrical connector, and more particular to an electrical receptacle connector. 
     BACKGROUND 
     Generally, Universal Serial Bus (USB) is a serial bus standard to the PC architecture with a focus on computer interface, consumer and productivity applications. The existing Universal Serial Bus (USB) interconnects have the attributes of plug-and-play and ease of use by end users. Now, as technology innovation marches forward, new kinds of devices, media formats and large inexpensive storage are converging. They require significantly more bus bandwidth to maintain the interactive experience that users have come to expect. In addition, the demand of a higher performance between the PC and the sophisticated peripheral is increasing. The transmission rate of USB 2.0 is insufficient. As a consequence, faster serial bus interfaces such as USB 3.0, are developed, which may provide a higher transmission rate so as to satisfy the need of a variety devices. 
     An existing USB electrical receptacle connector includes an insulated housing and a metallic shell, wherein the insulated housing is received in the metallic shell. The metallic shell includes a plurality of grounding sheets and a plurality of breaches. One end of each of the grounding sheets is extended from an inner wall of the corresponding breach, so that effective noise grounding and conduction can be accomplished via the grounding sheets which are respectively inserted into the through holes of the circuit board. 
     Nevertheless, during operation, the existing USB electrical receptacle connector provides poor shielding performance due to exposure of the breaches of the metallic shell, causing interference problems such as electromagnetic interference (EMI), radio frequency interference (RFI), etc. As a result, severe crosstalk problems are common when the existing USB electrical receptacle connector is used for signal transmission. 
     SUMMARY OF THE INVENTION 
     It is therefore necessary to establish and develop a new architecture of USB connectors to address the previously mentioned needs of platforms and devices, while retaining all of the functional benefits of USB that form the basis for this most popular of computing device interconnects. 
     In view of this, the instant disclosure provides an electrical receptacle connector. An embodiment of the electrical receptacle connector comprises an insulated housing, a plurality of upper-row receptacle terminals, a plurality of lower-row receptacle terminals, a metallic shell, and a plurality of connecting portions. The insulated housing comprises a base portion and a tongue portion extended from one side of the base portion in the front-to-rear direction, and the tongue portion has an upper surface and a lower surface. The upper-row receptacle terminals comprise a plurality of signal terminals, at least one power terminal, and at least one ground terminal. Each of the upper-row receptacle terminals is held in the base portion and disposed at the upper surface of the tongue portion. The lower-row receptacle terminals comprise a plurality of signal terminals, at least one power terminal, and at least one ground terminal. Each of the lower-row receptacle terminals is held in the base portion and disposed at the lower surface of the tongue portion. The insulated housing is received in a receiving cavity defined in the metallic shell. The metallic shell comprises a tubular body, at least one connecting plate, and at least one folded portion. The tubular body has an outer wall and an inner wall. The connecting plate is at the outer wall or the inner wall. The folded portion is extended from the tubular body toward the at least connecting plate. The connecting portions are configured to connect the connecting plate to the tubular body so that the connecting plate is fixed on the tubular body. 
     In conclusion, the connecting plates are configured to two sides of the tubular body by the connecting portions, so that the connecting plates are fixed with the tubular body, and the distance between the connecting plates are fixed to allow the through-hole legs of the connecting plates to be inserted into the through holes of the circuit board. Furthermore, since the folded portions and the connecting plates are configured to the two sides of the tubular body, the existing insufficient shielding issue caused by the breaches of the existing connector can be improved. Additionally, improved noise grounding and conduction can be accomplished, thereby performing a better EMI shielding so as to reduce the EMI and RFI problems. Furthermore, pin-assignments of the upper-row receptacle terminals and the lower-row receptacle terminals are 180 degree symmetrical, dual or double orientation design which enable an electrical plug connector to be inserted into the electrical receptacle connector in either of two intuitive orientations, i.e., in either upside-up or upside-down directions. In other words, the pin-assignments of the upper-row receptacle terminals and the lower-row receptacle terminals have 180 degree symmetrical, dual or double orientation design with respect to a central point of the receptacle cavity as the symmetrical center. Consequently, an electrical plug connector is inserted into the electrical receptacle connector with a first orientation where the upper surface of the tongue portion is facing up, for transmitting first signals. Conversely, the electrical plug connector is inserted into the electrical receptacle connector with a second orientation where the upper surface of the tongue portion is facing down, for transmitting second signals. Furthermore, the specification for transmitting the first signals is conformed to the specification for transmitting the second signals. 
     Detailed description of the characteristics, and the advantages of the instant disclosure, are shown in the following embodiments. The technical content and the implementation of the instant disclosure should be readily apparent to any person skilled in the art from the detailed description, and the purposes and the advantages of the instant disclosure should be readily understood by any person skilled in the art with reference to content, claims and drawings in the instant disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The instant disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus not limitative of the instant disclosure, wherein: 
         FIG. 1  is a perspective view of an electrical receptacle connector according to a first embodiment of the instant disclosure; 
         FIG. 2  is an exploded view of the electrical receptacle connector of the first embodiment; 
         FIG. 3  is an exploded view ( 1 ) showing an insulated housing and receptacle terminals received in the metallic shell of the electrical receptacle connector according to the first embodiment; 
         FIG. 4  is an exploded view ( 2 ) showing the insulated housing and the receptacle terminals received in the metallic shell of the electrical receptacle connector according to the first embodiment; 
         FIG. 5  is a sectional view showing a tubular body which includes a connecting plate and a folded portion according to the first embodiment; 
         FIG. 6  is a front sectional view of the electrical receptacle connector of the first embodiment; 
         FIG. 6A  is a schematic configuration diagram of the receptacle terminals of the electrical receptacle connector of the first embodiment; 
         FIG. 7  is a lateral sectional view of the electrical receptacle connector of the first embodiment; 
         FIG. 8  is a perspective schematic view showing the connecting segments are configured to the connecting plates of the electrical receptacle connector of the first embodiment; 
         FIG. 9  is a sectional schematic view showing the connecting segments are configured to the connecting plates of the electrical receptacle connector of the first embodiment; 
         FIG. 10  is a perspective view of an electrical receptacle connector according to a second embodiment of the instant disclosure; and 
         FIG. 11  is a perspective view of an electrical receptacle connector according to a third embodiment of the instant disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1  to  FIG. 4 , which illustrate an electrical receptacle connector  100  according to a first embodiment of the instant disclosure.  FIG. 1  is a perspective view of an electrical receptacle connector  100  according to a first embodiment of the instant disclosure.  FIG. 2  is an exploded perspective view of the electrical receptacle connector  100  of the first embodiment.  FIG. 3  is an exploded view (1) showing an insulated housing  1  and receptacle terminals  2 ,  3  are to be received in a metallic shell  4  of the electrical receptacle connector  100 , according to first embodiment.  FIG. 4  is an exploded view (2) showing the insulated housing  1  and the receptacle terminals  2 ,  3  are to be received in the metallic shell  4  of the electrical receptacle connector  100 , according to the first embodiment. The electrical receptacle connector  100  described herein provides a USB Type-C connection interface. The electrical receptacle connector  100  comprises an insulated housing  1 , a plurality of upper-row receptacle terminals  2 , a plurality of lower-row receptacle terminals  3 , and a metallic shell  4 . 
     Please refer to  FIG. 2 ,  FIG. 3  and  FIG. 4 , in which the insulated housing  1  comprises a base portion  11  and a tongue portion  12 . Here, injection molding techniques are applied to form the base portion  11  and the tongue portion  12 . Furthermore, the insulated housing  1  can be formed by a unitary member or a multi-piece member. Additionally, the tongue portion  12  is extended from one side of the base portion  11  in the front-to-rear direction, and the tongue portion  12  has an upper surface  121  and a lower surface  122  in which the upper surface  121  is opposite to the lower surface  122 . 
     Please refer to  FIG. 2 , in which embodiment the electrical receptacle connector  100  further comprises a grounding sheet  6  disposed inside the insulation housing  1 . The grounding sheet  6  comprises a main body  60  and a plurality of contacts  62 . The main body  60  is disposed between the upper-row terminals  2  and the lower-row terminals  3 . That is, the main body  60  is formed between the base portion  11  and the tongue portion  12  to be between the upper-row terminals  2  and the lower-row terminals  3 . Furthermore, the contacts  62  that can be mounted or soldered on the surface of a printed circuit board (PCB) by using through-hole technology are protruded out from the lateral sides of the base portion  21 . The structural strength of the tongue portion  12  can be improved by the grounding sheet  6  disposed inside the tongue portion  12 . Here, when the upper-row terminals  2  and the lower-row terminals  3  are transmitting USB 3.0 signals, effective noise grounding and conduction can be accomplished by connecting the contacts  62  of the grounding sheet  6  to the printed circuit board (PCB). Additionally, the grounding sheet  6  further comprises two lateral sides  600  which are protruded out the lateral sides of the tongue portion  12 . 
       FIG. 6  is a front sectional view of the electrical receptacle connector  100  of the first embodiment.  FIG. 7  is a lateral sectional view of the electrical receptacle connector  100  of the first embodiment. Please refer to  FIG. 3 ,  FIG. 6  and  FIG. 7 , in which the upper-row receptacle terminals  2  are held in the base portion  11  and disposed at the upper surface  121  of the tongue portion  12 . Each of the upper-row receptacle terminals  2  which are elongated and flat shapes comprises a flat contact portion  25 , a body portion  27 , and a tail portion  26 . The body portions  27  are held in the base portion  11  and disposed at the upper surface  121  of the tongue portion  12 . For each of the upper-row receptacle terminals  2 , the flat contact portion  25  is extended from one of two ends of the body portion  27  and disposed at the upper surface  121  of the tongue portion  12 , and the tail portion  26  is extended from the other end of the body portion  27  and exposed out of the base portion  11 . Furthermore, the tail portions  26  are extended out of a bottom of the base portion  11 . Furthermore, the tail portions  26  are bent horizontally to form flat legs, named SMT legs, which can be mounted or soldered on the surface of a printed circuit board (PCB) by using surface mount technology, as shown in  FIG. 4 . 
     Please refer to  FIG. 4 ,  FIG. 6  and  FIG. 7 , in which the lower-row receptacle terminals  3  are held in the base portion  11  and disposed at the lower surface  122  of the tongue portion  12 . The lower-row receptacle terminals  3  are configured below the upper-row receptacle terminals  2  with interval. Each of the lower-row receptacle terminals  3  which are elongated and flat shapes comprises a flat contact portion  35 , a body portion  37 , and a tail portion  36 . The body portions  37  are held in the base portion  11  and disposed at the lower surface  122  of the tongue portion  12 . For each of the lower-row receptacle terminals  3 , the flat contact portion  35  is extended from one of two ends of the body portion  37  and disposed at the lower surface  122  of the tongue portion  12 , and the tail portion  36  is extended from the other end of the body portion  37  and exposed out of the base portion  11 . Furthermore, the tail portions  36  are extended out of the bottom of the base portion  11 . Furthermore, the tail portions  36  are extended downward to form vertical legs, named through-hole legs, which can be mounted or soldered on the surface of a printed circuit board (PCB) by using through-hole technology, as shown in  FIG. 4 . In this embodiment, the tail portions  26 ,  36  are protruded out of the base portion  11  and arranged separately. For example, the tail portions  26 ,  36  form three rows. 
       FIG. 5  is a sectional view showing a tubular body  41  of the electrical receptacle connector  100  which further includes a connecting plate  42  and a folded portion  43  according to the first embodiment. Please refer to  FIG. 2 ,  FIG. 5  and  FIG. 7 , in which the metallic shell  4  defines a receiving cavity  40  therein to receive the insulated housing  1 . In this embodiment, the metallic shell  4  comprises a tubular body  41 , a plurality of connecting plates  42 , and a plurality of folded portions  43 . Additionally, the metallic shell  4  is a hollowed shell, and the tubular body  41 , the connecting plates  42 , and the folded portions  43  are formed by bending and machining a one-piece plate. That is, the tubular body  41 , the connecting plates  42 , and the folded portions  43  are formed integrally as a whole, and the connecting plates  42  and the folded portions  43  are formed on the tubular body  41  by bending processes. In this embodiment, the tubular body  41  has an outer wall  411  and an inner wall  412 . The outer wall  411  is formed at the exterior of the tubular body  41 , and the inner wall  412  is formed at the interior of the tubular body  41 . Here, the outer wall  411  is defined by a top plane  4111 , a bottom plane  4112 , and a plurality of lateral planes  4113 , and the lateral planes  4113  are extended from two sides of the top plane  4111  toward two sides of the bottom plane  4112  respectively. That is, the top plane  4111 , the bottom plane  4112  and the lateral planes  4113  define the hollow shell. Additionally, each of the connecting plates  42  is a thin plate. The connecting plates  42  are at the outer wall  4111 , so that the connecting plates  42  are stacked on the tubular body  41 . That is, the connecting plates  42  are disposed on the lateral planes  4113  respectively. Some of the connecting plates  42  further comprise at least one through-hole leg  421 , which is adapted for being mounted on a printed circuit board (PCB) by through-hole technology. The through-hole leg  421  is extended from the connecting plate  42  downward and vertically. The connecting plates  42  are disposed at the outer wall  411 , and the through-hole leg  42  is extended under a bottom of the insulated housing  1 . The folded portions  43  are respectively extended from two sides of the tubular body  41  toward the connecting plates  42 . Furthermore, one of two ends of the folded portion  43  is extended from the periphery of the tubular body  41 , and the other end of the folded portion  43  is extended toward the corresponding connecting plate  42 . Additionally, a front window  4131 , rectangular-shaped or oblong-shaped, is formed at one side of the metallic shell  4 . The front window  4131  communicates with the receiving cavity  40 . Furthermore, the folded portions  43  are respectively extended from two sides of the periphery of the front window  4131  toward the connecting plates  42 . Accordingly, some of the folded portions  43  and the connecting plates  42  are formed on the front part of the tubular body  41  with the folded portions  43  being folded backward with respect to the connecting plates  42  and some of the folded portions  43  and the connecting plates  42  are formed on the rear part of the tubular body  41  with the folded portions  43  being folded forwardly with respect to the connecting plates  42 , but embodiments are not limited thereto. 
     Please refer to  FIG. 2  and  FIG. 5 , in which a plurality of connecting portions  5  is configured to fix the connecting plates  42  to the tubular body  41 . The connecting portions  5  are respectively provided to fix the tubular body  41  with the connecting plates  42 . The methods for fixing the tubular body  41  with the connecting plates  42  are described as following. In one implementation aspect, each of the connecting portions  5  comprises a connecting point  51  configured to the connecting plate  42 , such that the connecting plates  42  and the tubular body  41  are fixed with each other. That is, proper laser beam welding techniques may be applied on the surface of each of the connecting plates  42 , so that the connecting points  51  are formed on the connecting plates  42  and then connecting points  51  are configured on the outer wall  411  of the tubular body  41 . Therefore, the connecting plates  42  and the tubular body  41  are securely fixed with each other and formed as a unitary member. 
       FIG. 8  is a perspective schematic view showing the connecting segments  52  are configured to the connecting plates  42  of the electrical receptacle connector  100  of the first embodiment.  FIG. 9  is a sectional schematic view showing the connecting segments  52  are configured to the connecting plates  42  of the electrical receptacle connector  100  of the first embodiment. Please refer to  FIG. 8  and  FIG. 9 . In another implementation aspect, each of the connecting portions  5  comprises a connecting segment  52  configured to lateral peripheries of the connecting plate  42  and the tubular body  41 . That is, proper tin-soldering techniques may be applied to connect the lateral peripheries of the connecting plates  42  with the outer wall  411  of the tubular body  41 , so that the connecting plates  42  and the tubular body  41  are securely fixed with each other. During the soldering process, soldering materials (for example, tin) are applied to the lateral peripheries of the connecting plates  42 , so that the lateral peripheries of the connecting plates  42  form a soldered segment to combine with the outer wall  411  of the tubular body  41 . Therefore, the connecting plates  42  and the tubular body  41  are securely fixed with each other and formed as a unitary member. 
     In some implementation aspects, each of the connecting plates  42  may comprise an abutting plate engaged with the tubular body  41 , so that the connecting plates  42  are connected securely with the tubular body  41 . Alternatively, the tubular body  41  may comprise a plurality of abutting plates respectively engaged with the connecting plates  42 , so that the tubular body  41  and the connecting plates  42  are connected securely with each other by the abutting plates. 
     To assemble the electrical receptacle connector  100  on a circuit board, the through-hole legs  421  of each of the connecting plates  42  are aligned to be inserted into the through holes of the circuit board, respectively. Hence, the connecting plates  42  are securely fixed to the two sides of the tubular body  41  by the connecting portions  5 , respectively. Therefore, the distance between the connecting plates  42  can be maintained from being too long or too short. Additionally, the metallic shell  4  is machined and bent by a unitary plate to form the tubular body  41 , the connecting plates  42 , and the folded portions  43 . Thus, two sides of the tubular body  41  are grounded by the through-hole legs  421  of the connecting plates  42 , so that the poor-shielding problems caused by the breaches of the existing connector can be improved. Conversely, based on embodiments of the instant disclosure, the tubular body  41  having the through-hole legs  421  can also prevent the EMI and RFI problems raised by the breaches of the existing connector. 
     Please refer to  FIG. 6 ,  FIG. 6A  and  FIG. 7 , in which the upper-row receptacle terminals  2  comprise a plurality of signal terminals  21 , a plurality of power terminals  22 , and a plurality of ground terminals  23 . The upper-row receptacle terminals  2  comprise, from left to right, a ground terminal  23  (Gnd), a first pair of differential signal terminals (TX 1 +−), a second pair of differential signal terminals (D+−), and a third pair of differential signal terminals (RX 2 +−) of the signal terminals  21 , power terminals  22  (Power/VBUS) between the three pairs of differential signal terminals, a retain terminal (RFU) and another ground terminal  23  (Gnd). However, the pin assignments are not thus limited, and the example described here is only for illustrative purposes. In this embodiment, twelve upper-row receptacle terminals  2  are provided for transmitting USB 3.0 signals, but embodiments are not limited thereto. In some implementation aspects, the far right ground terminal  23  (or the far left ground terminal  23 ) and the retain terminal are omitted. Furthermore, the far right ground terminal  23  may be replaced by a power terminal  22  and provided for power transmission. That is, the upper-row receptacle terminals  2  may comprise plural signal terminals  21 , at least one power terminal  22 , and at least one ground terminal  23 . 
     Please refer to  FIG. 6  and  FIG. 7 , in which the lower-row receptacle terminals  3  comprise a plurality of signal terminals  31 , a plurality of power terminals  32 , and a plurality of ground terminals  33 . The lower-row receptacle terminals  3  comprise, from right to left, a ground terminal  33  (Gnd), a first pair of differential signal terminals (TX 2 +−), a second pair of differential signal terminals (D+−), and a third pair of differential signal terminals (RX 1 +−) of the signal terminals  31 , power terminals  32  (Power/VBUS), between the three pairs of differential signal terminals, a retain terminal (RFU) and another ground terminal  33 . However, the pin assignments are not thus limited, and the example described above is only for illustrative purposes. In this embodiment, twelve lower-row receptacle terminals  3  are provided for transmitting USB 3.0 signals, but embodiments are not limited thereto. In some implementation aspects, the far right ground terminal  33  (or the far left ground terminal  33 ) and the retain terminal are omitted. Additionally, the far right ground terminal  33  may be replaced by a power terminal  32  and provided for power transmission. That is, the lower-row receptacle terminals  3  may comprise plural signal terminals  31 , at least one power terminal  32 , and at least one ground terminal  33 . 
     In the previous embodiments, the upper-row receptacle terminals  2  and the lower-row receptacle terminals  3  meet the transmission of USB 3.0 signals, but embodiments are not limited thereto. In some implementation aspects, for the upper-row receptacle terminals  2  in accordance with transmission of USB 2.0 signals, the first and third pairs of differential signal terminals are omitted, and the second pair of differential signal terminals and the power terminals  22  are retained for transmitting USB 2.0 signals. For the lower-row receptacle terminals  3  in accordance with transmission of USB 2.0 signals, the first and third pairs of differential signal terminals are omitted, and the second pair of differential signal terminals and the power terminals  32  are retained for transmitting USB 2.0 signals. 
     Please refer to  FIG. 2 ,  FIG. 6 ,  FIG. 6A  and  FIG. 7 , in which embodiment the upper-row receptacle terminals  2  and the lower-row receptacle terminals  3  are respectively disposed at the upper surface  121  and the lower surface  122  of the tongue portion  12 . Furthermore, the upper-row receptacle terminals  2  and the lower-row receptacle terminals  4  are point-symmetrical with a central point of the receptacle cavity  40  as the symmetrical center. In other words, pin-assignments of the upper-row receptacle terminals  2  and the lower-row receptacle terminals  3  have 180 degree symmetrical design with respect to the central point of the receptacle cavity  10  as the symmetrical center. The dual or double orientation design enables an electrical plug connector to be inserted into the electrical receptacle connector  100  in either of two intuitive orientations, i.e., in either upside-up or upside-down directions. Here, point-symmetry means, after the upper-row receptacle terminals  2  (or the lower-row receptacle terminals  3 ) are rotated by 180 degrees with the symmetrical center as the rotating center, the upper-row receptacle terminals  2  and the lower-row receptacle terminals  3  are overlapped. That is, the rotated upper-row receptacle terminals  2  are arranged at the position of the original lower-row receptacle terminals  3 , and the rotated lower-row receptacle terminals  3  are arranged at the position of the original upper-row receptacle terminals  2 . In other words, the upper-row receptacle terminals  2  and the lower-row receptacle terminals  3  are arranged upside down, and the pin assignments of the upper-row receptacle terminals  2  are left-right reversal with respect to the pin assignments of the lower-row receptacle terminals  3 . Accordingly, an electrical plug connector is inserted into the electrical receptacle connector  100  with a first orientation where the upper surface  121  of the tongue portion  12  of the electrical receptacle connector  100  is facing upward, for transmitting first signals. Conversely, the electrical plug connector is inserted into the electrical receptacle connector  100  with a second orientation where the upper surface  121  of the tongue portion  12  of the electrical receptacle connector  100  is facing downward, for transmitting second signals. The specification for transmitting the first signals conforms to that for transmitting the second signals. Based on this, the inserting orientation of the electrical plug connector is not limited by the electrical receptacle connector  100 . 
     Please refer to  FIG. 2 ,  FIG. 6 ,  FIG. 6A , and  FIG. 7 , in which embodiment positions of the upper-row receptacle terminals  2  correspond to positions of the lower-row receptacle terminals  3 . 
     Please refer to  FIG. 4  and  FIG. 7 , in which embodiment, the tubular body  41  further comprises a rear cover plate  414 . The rear cover plate  414  covers the back side of the receptacle cavity  40 , so that the exposed area of the metallic shell  4  can be reduced. The folded portions  43  are respectively extended from two sides of the rear cover plate  414  toward the connecting plates  42 . That is, each of the folded portions  43  is at the corresponding side of the rear cover plate  414  and extended toward the corresponding connecting plate  42 . Furthermore, the connecting plates  42  are at the outer wall  411 . That is, the connecting plates  42  are respectively at the lateral planes  4113 . The rear cover plate  414  comprises a plurality of through-hole legs  4141  extended from a bottom of the rear cover plate  414  toward the bottom of the insulated housing  1 . The through-hole legs  4141  are extended downward and vertically, so that noise grounded can be accomplished by the through-hole legs  4141 . Here, the folded portions  43  and the connecting plates  42  are formed on the rear part of the tubular body  41  with the folded portions  43  being folded forward with respect to the connecting plates  42 , but embodiments are not limited thereto. In addition, the connecting portions  5  are provided to fix the tubular body  41  with the connecting plates  42  at the two sides of the rear cover plate  414 . The methods for fixing the connecting plates  42  with the tubular body  41  are provided as above. Under such arrangement, the tubular body  41  and the connecting plates  42  are securely fixed with each other by the connecting portions  5 , and the rear cover plate  414  is securely fixed with the rear part of the tubular body  41 . 
     After the through-hole legs  4141  of the rear cover plate  414  are inserted into the through holes of the circuit board and applied with proper soldering techniques, the rear cover plate  414  is securely covered on the rear part of the tubular body  41 . Therefore, the electrical receptacle connector  100  can be securely fixed with the circuit board. As a result, when the electrical receptacle connector  100  is connected to an electrical plug connector with the electrical receptacle connector  100  being pulled unintentionally, gaps are not formed between the rear cover plate  414  and the metallic shell  4 , and the shielding function of the metallic shell  4  can be provided efficiently for the components inside the metallic shell  4 . That is, the through-hole legs  4141  of the rear cover plate  414  strengthen the positioning force for the electrical receptacle connector  100  to secure with the circuit board. Therefore, the electrical receptacle connector  100  provides better results in bending tests and wrenching strength. Additionally, the through-hole legs  4141  of the rear cover plate  414  are soldered on the circuit board to reduce the grounding resistance and the electromagnetic interference (EMI). 
       FIG. 10  is a perspective view of an electrical receptacle connector  100  according to a second embodiment of the instant disclosure. The structure of the second embodiment is approximately the same as that of the first embodiment, except that in the second embodiment, one folded portion  43  is provided and extended from the periphery of a top portion of the front window  4131  toward the connecting plate  42 . Here, the electrical receptacle connector  100  comprises one connecting plate  42 , and the connecting plate  42  is a unitary plate. The connecting plate  42  comprises a top plate  422  and a plurality of lateral plates  423 . The top plate  422  is at the top plane  4111 , and the lateral plates  423  are at the lateral planes  4113 , respectively. The through-hole legs  421  are respectively at the lateral plates  423  and extended downward and vertically. The through-hole legs  421  are extended toward the bottom of the insulated housing  1 . The folded portion  43  is extended from the periphery of the top portion of the front window  4131  and bent toward the top plate  422 . Under this arrangement, the folded portion  43  and the connecting plate  42  are formed on the front part of the tubular body  41  with the folded portion  43  being folded upward with respect to the connecting plate  42 . Additionally, the connecting portions  5  are provided to fix the tubular body  41  with the connecting plate  42 . That is, the connecting portions  5  can be configured on the top plate  422 , on the lateral plates  423  of the connecting plate  42 , or on both the top plate  422  and the lateral plates  423  of the connecting plate  42 , so that the tubular body  41  and the connecting plate  42  are fixed with each other by the connecting portions  5 . The methods for fixing the connecting plate  42  with the tubular body  41  are provided as above. Here, the connecting plate  42  is provided to cover the tubular body  41  so as to strengthen the architecture of the tubular body  41 . Further, the area for machining and configuring the connecting portions  5  is increased so as to simplify the machining process, improve the fixing function, and to stably confine the distance between the through-hole legs  421 . 
       FIG. 11  is a perspective view of an electrical receptacle connector  100  according to a third embodiment of the instant disclosure. The structure of the third embodiment is approximately the same as that of the first embodiment, except that in the third embodiment, the tubular body  41  further comprises a rear window  4132 . At least two folded portions  43  are extended from two sides of the rear window  4132 . That is, the folded portions  43  are respectively extended from upper and lower sides of the rear window  4132  toward at least two connecting plates  42 , and the connecting plates  42  are respectively at an upper inner wall and a lower inner wall of the tubular body  41 , as shown in  FIG. 11 . Additionally, the connecting portions  5  are configured to fix the connecting plates  42  to the tubular body  41 . That is, the connecting portions  5  can be formed by applying proper machining techniques to the exterior of the tubular body  41 . Taking laser beam welding technique as an example, laser beams are applied to the top and the bottom of the tubular body  41 , so that the connecting portions  5  are provided to fix the tubular body  41  with the connecting plates  42 . The methods for fixing the tubular body  41  with the connecting plates  42  by the connecting portions  5  are provided as above, and accordingly the connecting plates  42  and the tubular body  41  are firmly fixed with each other. Here, an electrical plug connector  200  comprises a tubular portion  202  formed at a front portion of a metallic shell  201  thereof. When the electrical plug connector  200  is mated with the electrical receptacle connector  100 , the tubular portion  202  of the electrical plug connector  200  is in contact with the connecting plates  42  in the tubular body  41 , so that the metallic shell  201  of the electrical plug connector  200  is in contact with the metallic shell  4  of the electrical receptacle connector  100  for effective noise conduction, thereby improving the existing EMI problem. 
     In conclusion, the connecting plates are configured to two sides of the tubular body by the connecting portions, so that the connecting plates are fixed with the tubular body, and the distance between the connecting plates are fixed, allowing the through-hole legs of the connecting plates to be inserted into the through holes of the circuit board. Furthermore, since the folded portions and the connecting plates are configured to the two sides of the tubular body, the existing insufficient shielding issue caused by the breaches of the existing connector can be improved. Additionally, improved noise grounding and conduction can be accomplished, thereby performing a better EMI shielding so as to reduce the EMI and RFI problems. Furthermore, pin-assignments of the upper-row receptacle terminals and the lower-row receptacle terminals are 180 degree symmetrical, dual or double orientation design which enable an electrical plug connector to be inserted into the electrical receptacle connector in either of two intuitive orientations, i.e., in either upside-up or upside-down directions. In other words, the pin-assignments of the upper-row receptacle terminals and the lower-row receptacle terminals have 180 degree symmetrical, dual or double orientation design with respect to a central point of the receptacle cavity as the symmetrical center. Consequently, an electrical plug connector is inserted into the electrical receptacle connector with a first orientation where the upper surface of the tongue portion is facing up, for transmitting first signals. Conversely, the electrical plug connector is inserted into the electrical receptacle connector with a second orientation where the upper surface of the tongue portion is facing down, for transmitting second signals. Furthermore, the specification for transmitting the first signals is conformed to the specification for transmitting the second signals. 
     While the instant disclosure has been described by the way of example and in terms of the preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.