referring to fig1 , a quick - detachable modular jack and face panel mounting structure in accordance with the present invention is shown comprising a face panel 10 , an inner positioning frame 30 mounted at a back side of the face panel 10 , two limiter plates 40 , a plurality of control rods 50 , and a plurality of modular jacks 20 mounted in the inner positioning frame 30 and the face panel 10 in rows . referring to fig2 , the face panel 10 comprises at least one , for example , two elongated slots 11 cut through opposing front and back sides thereof and horizontally disposed at different elevations in a parallel manner , and top and bottom flanges 12 ; 13 respectively backwardly extended from opposing top and bottom sides thereof in a parallel manner . the inner positioning frame 30 is mounted at the back side of the face panel 10 between the top and bottom flanges 12 ; 13 , and adapted to hold the modular jacks 20 in two rows in the elongated slots 11 . referring to fig3 and fig2 again , the inner positioning frame 30 comprises a front panel 33 and a back panel 34 vertically arranged in a parallel manner , and opposing top and bottom panel 32 horizontally connected between the front panel 33 and the back panel 34 at opposing top and bottom sides , a plurality of front window openings 31 and rear window openings 341 respectively and symmetrically cut through the front panel 33 and the back panel 34 and arranged in two rows corresponding to the two elongated slots 11 of the face panel 10 for the mounting of the modular jacks 20 , and two rows of constraint structures corresponding to the window openings 31 . each constraint structure comprises two stop blocks 35 ; 36 backwardly extended from the front panel 33 adjacent to the top or bottom panel 32 and spaced from each other at a predetermined distance , and two plug holes 37 ; 38 located at the top or bottom panel 32 adjacent to the stop blocks 35 ; 36 . each window opening 31 forms with one elongated slot 11 a respective modular jack hole for accommodating one respective modular jack 20 . the two limiter plates 40 are respectively attached to the two rows of constraint structures between the front panel 33 and the back panel 34 . each limiter plate 40 comprises a plurality of guide blocks 41 respectively disposed corresponding to one respective constraint structure , pairs of plug rods 42 pluggable into the plug holes 37 ; 38 of the respective constraint structures , and a plurality of guide notches 43 respectively slidably coupled to respective back panel components 342 of the back panel 34 . the back panel 34 comprises a step 343 at one end of each back panel component 342 , defining a dead center to limit the sliding movement of the limiter plate 40 along the back panel components 342 . each control rod 50 comprises opposing front engagement end 501 and rear operating end 502 . the front engagement end 501 is engageable into the inner positioning frame 30 for enabling the respective control rod 50 to secure one respective modular jack 20 . after installation of one control rod 50 in the inner positioning frame 30 to secure one respective modular jack 20 , the rear operating end 502 suspends outside the inner positioning frame 30 for operation by the user to release the mounted modular jack 20 . the control rod 50 has a predetermined width . each control rod 50 further comprises at least one , for example , two spring springy retaining arms 51 ; 52 obliquely backwardly extended from two opposite lateral sides of the front engagement end 501 , and a guide slot 53 longitudinally located on the middle of the front engagement end 501 and coupled to one guide block 41 of one limiter plate 40 . referring to fig3 again , the front engagement ends 501 of the control rods 50 are respectively inserted into the inner positioning frame 30 . in fig3 , two control rods 50 are shown wherein the front engagement ends 501 of the right control rod 50 is initially inserted in between the two stop blocks 35 ; 36 of one respective constraint structure ; the front engagement ends 501 of the left control rod 50 has been inserted in between the two stop blocks 35 ; 36 of one respective constraint structure in position . after insertion of the front engagement ends 501 of the control rods 50 into the gap between the two stop blocks 35 ; 36 of each of the constraint structures , the limiter plates 40 are respectively lowered or lifted toward the top or bottom panel 32 ( see also fig4 ) to force the respective plug rods 42 into the respective plug holes 37 ; 38 and to couple the respective guide blocks 41 to the guide slots 53 of the control rods 50 . at this time , the front engagement end 501 of each control rod 50 is kept spaced from the front panel 33 of the inner positioning frame 30 by an operating gap a ( see fig6 and fig7 ), and the spring springy retaining arms 51 ; 52 of each control rod 50 are respectively terminating in a respective free end . according to the present preferred embodiment , each limiter plate 40 further comprises a plurality of end flanges 44 extending from a rear side thereof at right angles , a rear opening 45 located on each end flange 44 corresponding to one respective guide block 41 . the width of the rear openings 45 fits the width of the control rods 50 . when the limiter plates 40 are respectively lowered or lifted toward the top or bottom panel 32 to force the respective plug rods 42 into the respective plug holes 37 ; 38 , the rear openings 45 of the limiter plates 40 are respectively attached to the control rods 50 tightly . each limiter plate 40 further comprises a plurality of open slots 46 ; 47 respectively disposed at two opposite lateral sides relative to each of the end flanges 44 to expose the springy retaining arms 51 ; 52 of the control rods 50 . referring to fig4 and 5 again , each modular jack 20 comprises a fastening structure . the fastening structure comprises at least one , for example , a plurality of hook blocks 21 protruded from periphery thereof for engagement with the springy retaining arms 51 ; 52 of one respective control rod 50 . fig6 illustrates two modular jacks 20 inserted into the inner positioning frame 30 , wherein the left modular jack 20 is partially inserted into the inner positioning frame 30 ; the right modular jack 20 has been fully inserted into the inner positioning frame 30 and locked by the springy retaining arms 51 ; 52 of the respective control rod 50 . fig7 illustrates one modular jack 20 ( the one on the right side ) locked to the inner positioning frame 30 and another modular jack 20 ( the one on the left side ) unlocked from the inner positioning frame 30 . because an operating gap a is left between the front engagement end 501 of each control rod 50 and the front panel 33 of the inner positioning frame 30 , the control rod 50 can be pushed inward to disengage the respective springy retaining arms 51 ; 52 from the respective hook blocks 21 of the respective modular jack 20 , allowing the respective modular jack 20 to be removed from the inner positioning frame 30 . the quick - detachable modular jack and face panel mounting structure of the present invention is suitable for use in a small - sized , high - density network system to hold a large amount of modular jacks in rows . by means of operating the exposed control rods , loaded modular jacks can be quickly detached from the face panel and the inner positioning frame for replacement or repair . although a particular embodiment of the invention has been described in detail for purposes of illustration , various modifications and enhancements may be made without departing from the spirit and scope of the invention . accordingly , the invention is not to be limited except as by the appended claims .