reference will now be made in detail to the preferred embodiment of the present invention . fig1 - 8 show a plug connector 10 mated with a receptacle connector 50 mounted in a notch 102 of a printed circuit board . 100 , of a first embodiment of this present invention . the receptacle connector 50 includes an insulative housing 52 with a mating tongue 54 forwardly extending in a capsular mating cavity 57 of a metallic shield 56 which encloses the housing 52 . opposite upper and lower rows of contacts 58 are disposed in the housing 52 with corresponding contacting sections 60 exposed upon opposite surfaces of the mating tongue 54 in a diagonally symmetrical arrangement mechanically and electrically so as to allow a so - called flappable insertion of the plug connector 10 thereinto . a step structure 62 is formed around a root of the mating tongue 54 . a one piece metallic emi collar 64 includes a loop structure 66 intimately surrounding the step structure 62 . the collar 64 further includes an l - shaped extending plate 65 equipped with embossments 63 thereon and received in the recess 61 of the lower piece 72 of the housing 52 ( illustrated later ) for mechanically and electrically connecting to the shield 56 . the detailed structures of emi collar 64 may be also referred to the embodiment disclosed in fig1 . the housing 52 is composed of the upper piece 70 and a lower piece 72 commonly sandwiching therebeween a middle piece 74 which forms the mating tongue 54 . the upper row contacts 58 are associated with the upper piece 70 , the lower row contacts 58 are associated with a lower piece 72 and the shielding plate 76 is associated with the middle piece 74 via an insert molding process wherein the contacting sections 60 of the upper row contacts 58 and those of the lower rows contacts 58 are seated upon opposite upper surface and lower surface of the mating tongue 54 , respectively , as mentioned before . understandably , the housing 52 and the associated contacts 58 may be deemed wholly as a so - called terminal module implying the terminals being integrally formed within an insulator . a rear portion of the step structure 62 is removed to have a front edge region 71 of the upper piece 70 and the front edge region 73 of the lower piece 72 sandwiched between the middle piece 74 and the loop structure 66 of the emi collar 64 so as to enhance the strength during mating under some bending . in this embodiment , the shielding plate 76 defines an opening 77 and a thinner area 78 for both securing and impedance consideration , and further a pair of mounting legs 79 so as to efficiently separate the upper row contacts 58 and the lower row contacts 58 from each other wherein the upper row contacts 58 form the surface mount type tail sections while the lower row contacts 58 form the through hole type tail sections . in an alternate embodiment , the thinner area 78 may be totally removed from the shielding plate 76 . the lower piece 72 includes a pair of mounting posts 80 receiving in the corresponding through hole for mounting the housing 52 to the printed circuit board 100 . the lower piece 72 further forms a pair of recessions 49 to receive the corresponding retention tangs 37 of the shield 56 . in this embodiment , the middle piece 74 forms a pair of recesses 82 to respectively receive the corresponding protrusions 84 of the upper piece 70 and the lower piece 72 for securing the upper piece 70 , the lower piece 72 and the middle piece 74 therebetween in a stacked manner wherein the upper piece 70 further include a pair of downward assembling poles 84 received in the corresponding alignment holes 86 of the middle piece 74 , and the lower piece 72 further includes an upward assembling pole 85 received in the corresponding alignment holes 86 of the middle piece 74 , and the lower piece 72 further forms a pair of upward locating posts 87 received within the corresponding recesses 89 in the upper piece 70 . in this embodiment , the lower piece 72 defines a plurality of through holes 91 and 93 to receive the tail sections of the lower row contacts 58 and the mounting legs 79 of the shielding plate 76 to extend therethough as an alignment spacer . notably , the shielding plate 76 forms a front edge section 69 extending forwardly beyond a front edge of the mating tongue 54 for anti - mismating consideration , and a pair of lateral edge sections 67 for locking with a latch 39 of the plug connector 10 ( illustrated later ). in brief , the shielding plate 76 is essentially multifunctional to perform shielding , grounding , reinforcing , anti - mis - mating and locking . a metallic bracket 95 is soldered under the shield 56 and forms a pair of supporting legs 97 mounted into the through hole 103 of the printed circuit board 100 for supporting the receptacle connector 50 within the notch 102 of the printed circuit board 100 . the shield 56 further includes an upside - down u - shaped structure ( not labeled ) on a rear portion covering the rear portion of the housing 52 with a pair of mounting legs 55 received in the through holes 104 for mounting to the printed circuit board 100 and a pair of locking tabs 59 received in the recesses 99 of the upper piece 70 after the shield 56 is rearwardly assembled to the housing 52 in a front - to - back direction . notably , the mounting leg 79 of the shielding plate 76 share the same through hole with the neighboring grounding contact tail for enhancing grounding effect . referring to fig9 - 18 , according to a second embodiment of the invention the receptacle connector 200 mounted upon the printed circuit board 150 , includes an insulative housing 220 enclosed in the metallic shield 210 which is attached to a metallic bracket 212 which is surface - mounted upon the printed circuit board 150 . the housing 220 essentially includes a base 222 and a mating tongue 224 extending forwardly therefrom . two rows of passageways 226 extends along a front - to - back direction in the housing 220 , and each passageway 226 forms an inward recession 228 at a front end with a protection flange 270 thereabouts , and a platform 230 behind the recession 228 . a pair of opposite grooves 232 are located on two lateral sides of each passageway 226 . a plurality of contacts 240 are forwardly inserted to the corresponding passageways 226 , respectively . each contact 240 includes a horizontal main body 242 with two pairs of barbs 244 on two lateral edges to be engaged within the corresponding grooves 232 in an interference fit , a surface mount tail 246 behind the main body 242 , and a contacting section 248 in front of the main body 242 with a tip 2481 inwardly embedded with the recession 228 . the tails 246 are laterally offset from the main bodies 242 of the corresponding contacts 240 of the upper row with two opposite group while the those of the corresponding contacts of the lower row are still densely arranged with one another without offsetting . on the other hand , the tails 246 of the contacts 240 in the upper row and those in the lower row extend in opposite directions . notably , the front section of the contacting section 248 is supported by the platform 230 while the remaining contacting section 248 and the main body 242 are spaced from the housing 220 in the vertical direction with support by the pair of barbs 244 in the grooves 232 . a metallic shielding plate 250 is insert molded within the housing 220 and between the two rows of the contacts 240 before the contacts 240 are inserted into the housing 220 . the shielding plate 250 includes a first shielding portion 251 located between the contacts portions 248 of the upper and lower rows of contacts 240 and a second shielding portion 253 located between the tails 246 of the upper and lower rows of the contacts . the shielding plate 250 forms a pair of locking side edges 252 for locking with the internal latch of the corresponding plug , a pair of spring arms 254 located on two lateral sides thereof and in corresponding recesses 223 in opposite two lateral sides of the housing 220 to mechanically and electrically connect to the shield 210 , and a pair of contacting regions 256 unitarily extending respectively from two opposite lateral sides of the shielding plate 250 in a folded / parallel manner and exposed upon the root portion 225 of the mating tongue 224 for coupling to the corresponding spring plates on the plug connector . notably , the shielding plate 250 forms a plurality of through openings 258 to be filled with material of the housing 220 after the insert molding process for securing consideration . the shield 210 forms a mating cavity 211 into which the mating tongue 224 forwardly extending , and a plurality of spring tangs 213 extending rearwards and a plurality of dimples 215 for holding the plug connector . a rear wall 217 unitarily extends from a rear edge of the shield 210 to cover the back of the housing 220 with two ears 219 locked to the two lateral sides of the shield 210 and surface mounting type tail 218 . notably , the shield 210 essentially constitutes a capsular form with two vertical side walls 260 for locking the corresponding ears 219 where a pair of horizontal mounting pads 262 are formed for surface mounting to the printed circuit board 150 . the shield 210 includes a curved rear edge 268 rearwardly abuts against the base 222 of the housing 220 . the bracket 212 is attached to the shield 210 via tabs 264 and mounted to the printed circuit board via mounting pads 266 . different from the previous first embodiment , this second embodiment discloses the receptacle connector 200 completely mounted upon the printed circuit board 150 rather than partially sunk in the notch of the printed circuit board as shown in the previous embodiment . the contacts 240 are assembled into the corresponding passageways 226 rather than via an insert - molding process . on the other hand , the rear wall 217 may efficient block an emi in the front - to - back direction . the tip 2481 of the contacting section 248 is inward formed and received in the recession 228 and partially protectively covered by the flange 270 above the recession 228 for superior protection without a risk of pup - up . understandably , in this embodiment the housing 220 is restrained in the shield 210 via the rear wall 217 which forwardly abuts against a back side of the base 222 for blocking the rearward movement and via the rear edge 268 which rearward abuts against a forwardly facing vertical face of the base 222 for blocking the forward movement . fig1 - 21 disclose third embodiment of the receptacle connector 200 a essentially same as the previous second embodiment except the previous second embodiment is of a surface mount type while the current one is of the through hole type on the corresponding shield 210 and bracket structure 212 . the shield 210 and the bracket 212 define tails 262 a , 218 a , 266 a of surface mount type . anyhow , both of these two embodiments are of the surface mount type contacts , the tails of the contacts of the upper and lower rows extend in opposite directions . the shielding plate 250 further defines two tails 255 from the rear shielding portion 253 thereof . fig2 - 24 show a fourth embodiment of the receptacle connector 200 b similar to the embodiment disclosed in fig1 - 21 with tiny differences wherein the front edge 2121 of the shield 210 is equipped with a plurality of flared flanges for easy insertion of the plug connector . the shielding plate 250 defines two tails 255 b extending from the rear shielding portion 253 . fig2 ( a ) and 25 ( b ) show another embodiment of the shielding plate 250 ′ wherein the contacting regions 256 ′ is equipped with a lance 259 ′ at the tip to secured to the main body / the first shielding portion of the shielding plate 250 ′ so as to prevent tilting of the contacting regions 256 ′ relative to the shielding plate 250 ′ during the high pressure insert molding process . fig2 - 28 ( b ) show a fifth embodiment of the receptacle connector 600 mounted upon and within a notch of the printed circuit board 650 wherein the receptacle connector 600 includes a terminal module or an insulative housing ( not shown , which is similar to the previous embodiments ) enclosed within a metallic shield 602 which forms a capsular mating cavity or mating port 604 and is equipped with a plurality of spring tangs 606 extending into the mating cavity 604 for retaining the plug connector therein . different from the first embodiment disclosing the shield 50 forming both the front capsular section and the rear partially rectangular section , the shield 602 in this embodiment essentially only forms the front capsular section for easing manufacturing consideration . on the other hand , the bracket 95 in the first embodiment is attached to the bottom side of the shield 50 , while in this embodiment the metallic bracket 610 is secured to a top side of the shield 602 and forms not only the partially capsular front section 612 to compliantly cover the upper portion of the shield 602 but also the partially rectangular rear section 614 to compliantly cover the upstanding housing ( not shown ). to efficiently secure to the shield 602 , the top wall 616 and the side walls 618 of the front section 612 of the bracket 610 is welded to the shield 602 , and the rear section 614 forms securing tabs 620 for engagement within corresponding recesses in the top face of the housing ( not shown ). one feature of this embodiment is that the bracket 610 forms a curved or s - shaped cross - sectional joint section 622 between the front section 612 and the rear section 614 for compensating minor variations regarding the position of the shield 602 in the height direction which is expected to be little adjustable relative to the printed circuit board 650 . notably , the relative position of the mating port 604 with regard to the printed circuit board 650 may be different according to the computer maker so the adjustability of the mating port in the vertical direction is desired . to efficiently support the whole connector 600 within the notch 652 and upon the printed circuit board 650 , the front section 612 of the bracket 610 includes a pair of right angle legs 624 , and the rear section 614 of the bracket 610 includes a pair of right angle legs 626 for mounting to the printed circuit board 650 . the rear section 614 further includes a pair of securing arms 628 adjacent to the joint section 622 to be welded to the rear portion of the shield 610 for reinforcement of the whole connector structure around the joint section 622 , and a pair of mounting legs 630 around the rear face to be mounted to the printed circuit board 650 for reinforcing securing among the bracket 610 , the printed circuit board 650 and the housing ( not shown ) wherein the mounting legs 630 is closer to the securing tabs 620 which locks the housing ( not shown ). a pair of blocking tabs 632 are formed by two sides of the joint section 622 for preventing emi invasion along the front - to - back direction . it is noted that the shield 602 has a rear wall 634 and the bracket has a rear wall 636 both for emi protection along the front - to - back direction similar to the blocking tabs 632 . understandably , both the rear walls 634 , 636 may be secured to the corresponding side walls via a pair of locking ears as shown in the previous embodiments . understandably , the securing between the shield 602 and the bracket 610 via welding may be replaced with the mechanical latching tabs or similar mechanical means . referring to fig2 ( a ) - 36 showing a receptacle connector 300 of a sixth embodiment of this invention , the receptacle connector 300 mounted upon and within the notch of the printed circuit board 390 , includes a terminal module 310 essentially composed of an upper part 312 and a lower part 314 commonly sandwiching a shielding plate 316 therebetween and further integrated together with a middle insulator 318 . the upper part 312 includes a plurality of upper contacts 320 integrally formed within an upper insulator 322 via a first stage insert molding process , and the lower part 314 includes a plurality of lower contacts 324 integrally formed within a lower insulator 326 via another first stage insert molding process . the formed upper part 312 and the formed lower part 314 commonly sandwich the shielding plate 316 and integrally formed with the middle insulator 318 via a second stage insert molding process . notably , the upper emi collar 328 and the lower emi collar 330 are integrally formed with the corresponding upper part 312 and lower part 314 via the middle insulator 318 at the second stage insert molding process . the terminal module 310 formed by two - stage insert molding process can be referred to the previous filed application 62 / 001 , 084 . the terminal module 310 forms a mating tongue 332 on the front portion for mating with the corresponding plug connector . a metallic shield 334 is attached to the front portion of the terminal module 310 to enclose the mating tongue 332 to form a mating cavity 333 wherein a continuously uninterrupted flared flange 336 is formed at the front edge of the shield 334 in front of the mating cavity 333 and plurality of through holes 338 are formed in the shield 334 . the upper metallic bracket 340 is attached on an upper side of the shield 334 and the lower metallic bracket 342 is attached on a lower side of the shield 334 . the upper bracket 340 includes an upper rear wall 341 to shield the upper rear upper portion of the terminal module 310 and the lower bracket 342 includes a lower rear wall 343 to shield the lower rear portion of the terminal module 310 . the upper bracket 340 further includes a plurality of spring arms 345 with the engaging tips 346 extending through the corresponding through holes 338 into the mating cavity 333 for engagement with the plug connector . similarly , the lower bracket 342 further includes a plurality of spring arms 347 with the engaging tips 348 extending through the corresponding through holes 338 into the mating cavity 333 for engagement with the plug connector . the feature of this embodiment is to provide the continuously uninterrupted flared flange on the front edge of the shield 334 not only to protectively hide the front edges of the upper bracket 340 and the lower bracket 342 but also provide superior shielding effect circumferentially , compared with the interrupted flared flange disclosed in the prior art . it is also noted that because the fine pitch of the contacts of the receptacle connector , the traditional vias on the mother board are essentially unfit thereto , and the so - call micro vias are expected to be used for the fine pitch receptacle connector . anyhow , the expense of the pcb construction using micro vias is twice the price as standard pcb &# 39 ; s , and it is too expensive for the mother board size pcb &# 39 ; s . an alternative way is presented here to have it done economically . referring to fig3 - 42 ( c ) showing a seventh embodiment of this invention , a system includes a module 400 where the receptacle connector 410 and a chipset 440 for the wired signal are both mounted upon a small / low cost pcb 460 which is suitable for micro vias . the chipset 440 may be optionally covered by a metallic shell 442 . a card edge connector 470 is mounted upon the mother board 480 to receive one edge of the small pcb 460 for connection therebetween . understandably , the card edge connector 470 can be replaced with other type connector ( s ) or cable assemblies for connecting the small pcb 460 and the mother board 480 . understandably , even though two flippable receptacle connectors 410 are used with one chipset 440 , other number combinations can be used , e . g ., only one receptacle connector 410 cooperating with one chipset 440 as shown in fig3 - 42 ( c ). the receptacle connector 410 includes a terminal module enclosed in the metallic shield 418 and further is equipped with the upper metallic bracket 412 and the lower metallic bracket 414 so as to efficiently shield the whole connector 410 in the three dimensional way for full emi protection . notably , in this embodiment , the receptacle connector 410 is mounted within a notch 462 of the small pcb 460 in a sinking type for performing a lower profile configuration . similarly , the card edge connector 470 may be mounted within a notch of the mother board 480 in a similar way for lowering the profile of the whole assembly . fig4 through 49 show a receptacle connector 1000 of an eighth embodiment , the receptacle connector 1000 includes an insulating housing 1 with a base portion 10 and a mating tongue 11 , and contacts 2 and a pair of grounding piece 3 , a metallic shield 4 and an upper bracket 5 . the insulating housing 1 includes an upper parts 12 loaded with an upper row of the contacts , a lower part 13 loaded with a lower row of contacts and a middle part 14 loaded with a shielding plate 6 , the shielding plate is inserted molded with the middle parts . said three parts is vertically stacked with each other to for a sub - assembly and then the sub - assembly is inserted molded with an insulating base 15 . therefore , the insulative housing or terminal module is formed . the pair of grounding pieces 3 are assembled to the root of the mating tongue . the shielding plate 6 defines a front shielding portion 7 embedded in the mating tongue 11 and disposed between the contacts portions 21 of the upper and lower rows of the contacts 2 and a rear shielding portion 8 disposed between the tails 22 of the upper and lower rows of the contacts . tails 9 extend from the rear shielding portion 8 to be mounted on a printed circuit board . please notes , the insulating base 15 is only form the base portion of the insulating housing , the mating tongue 11 is formed by the middle part 14 , the contacting portions 21 of the contacts 2 are inserted in the terminal grooves defined on the mating tongue of the middle part . referring to fig5 , according to another embodiment similar to the first embodiment , to comply with the contour of the case in which the flippable receptacle connector is retained , the front edge of the metallic shield 56 ′ may be no longer a straight line extending along a vertical direction but a curved structure 561 ′, in a side view , with at least one rearwardly recessed portion on either the upper or lower side . anyhow , the distance measured from the outermost point of the curved front edge structure may be still same as that of the original one disclosed in the first embodiment without such the rearwardly recessed portion . fig5 shows another embodiment of the flippable receptacle connector 50 ′ wherein the contacts on each face of the mating tongue include a plurality of stationary contacts 581 in the front row and a plurality of deflectable contacts 582 in the rear row . the detailed structure may be referred to u . s . pat . no . 7 , 614 , 887 . referring to fig5 - 53 , according to an ninth embodiment of the invention , the vertical receptacle connector 500 is directly mounted upon the printed circuit board in an upstanding manner and includes a metallic shield 552 enclosing an insulative housing wherein the shield 552 forms a plurality of spring tangs 556 via corresponding cutouts 558 . a metallic bracket 560 surrounds the shield 552 and covers the spring tangs 556 and the corresponding cutouts 558 . the bottom portion of the shield 552 is split to outwardly extend for increasing the mounting area of the receptacle connector 550 so as to form a relative large gap 562 exposing the inner housing . a horizontal extension 564 is unitarily formed on the bottom portion to cover the gap mostly . understandably , both the bracket 560 and the horizontal extension 564 are to cover the corresponding cutout 558 and gap 562 for preventing emi . on the other hand , the bracket 560 also aids in strength and waterproofing and the horizontal extension 564 helps on stability of the receptacle connector 500 on the printed circuit board . on the other hand , each of the lateral end side of the shield 552 is equipped with two grounding legs 559 instead of one to enhance the emi protection . however , the disclosure is illustrative only , changes may be made in detail , especially in matter of shape , size , and arrangement of parts within the principles of the invention .