Patent Publication Number: US-7914331-B2

Title: Plug connector for telecommunications and data technology

Description:
This application is a National Stage Application of PCT/EP2007/006363, filed Jul. 18, 2007, which claims benefit of Ser. No. 10 2006 036 459.7, filed Aug. 4, 2006 in Germany and which application(s) are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     The invention relates to a plug-in connector for telecommunications and data technology. 
     Such plug-in connectors are, for example, RJ45 sockets or plugs, such a generic RJ45 socket being described in WO 02/15339. 
     Furthermore, DE 298 19 314 U1 has disclosed a socket-type plug-in connector having a dielectric plug-in connector housing and contacts arranged in the plug-in connector housing for the purpose of producing a connection with the contacts of an associated plug-in connector which has been inserted into an insertion opening in the plug-in connector housing, and having external connection contacts for the purpose of producing an electrical connection with the socket-type plug-in connector, having an arrangement for the purpose of DC-decoupling the contacts for the associated plug-in connector from the external connection contacts and having a filter device, an element being provided which can be inserted essentially completely into the plug-in connector housing and holds both the contacts for the associated plug-in connector and the external connection contacts, and in which both the arrangement for the DC-decoupling and the filter device are arranged. The arrangement for the DC-decoupling and the filter device comprise inductances which are formed by coils having a ferrite ring core, whose center axes are aligned in each case parallel to one another. Transformers for the DC-decoupling act as a bandpass filter, which is disadvantageous in particular in the case of broadband transmissions in accordance with CAT6 and 10 gigabit/s Ethernet applications. 
     In the case of CAT6 or 10 gigabit/s Ethernet applications, in addition to the known crosstalk effects within a plug-in connector, such as NEXT (near end crosstalk) and FEXT (far end crosstalk), there is an increased influence of the so-called ANEXT (alien near end crosstalk) or AFEXT (alien far end crosstalk) in adjacent plug-in connectors. The influence of the ANEXT or AFEXT increases severely at higher signal transmission rates. This AXT (alien crosstalk) comprises the direct AXT between the plug-in connectors and the indirect AXT via the differential mode to common mode conversion of the plug-in connector, the common-mode coupling between the connected cables and the common mode to differential mode conversion in the plug-in connector which is subjected to the interference. 
     The invention is therefore based on the technical problem of providing a plug-in connector for telecommunications and data technology, by means of which the influence of the AXT is reduced at high transmission rates of CAT6 or 10 gigabit/s Ethernet. 
     In this regard, in each case one common-mode filter arrangement is assigned to all of the core pairs. An interfering common-mode signal is thereby attenuated in pairs, with the result that this attenuated common-mode component does not lead to AXT in an adjacent plug-in connector. At the same time, the common-mode filter arrangement also attenuates injected common-mode signals from other plug-in connectors. 
     In one preferred embodiment, the common-mode filter arrangement is in the form of a common-mode inductor, which is arranged on a printed circuit board for the first and second contacts, the common-mode inductor preferably being in the form of an SMD component, which allows for a compact design. The common-mode inductor is in this case preferably electrically connected between the first and second contacts. 
     As an alternative or in addition, the common-mode arrangement can be in the form of a ferrite sleeve, a dedicated ferrite sleeve being assigned to each core pair, whereas an individual ferrite sleeve would have virtually no effect for the entire cable. The reason for this is the fact that the common-mode signals on the different core pairs do not necessarily have the same direction. The common-mode interference therefore needs to be reduced separately for each core pair. 
     Various embodiments are now possible for connecting the ferrite sleeves to the plug-in connector or the plug-in connector housing. 
     In one embodiment, the ferrite sleeves are in the form of a separate component and are fixed, for example latched or adhesively bonded, to the plug-in connector housing. In addition it is also possible to provide a separate ferrite sleeve holder which holds the ferrite sleeves, the ferrite sleeve holder itself being held by the housing of the plug-in connector or the cores. In this case, the ferrite sleeve holder is preferably designed such that the individual ferrite sleeves do not come into contact with one another and therefore magnetic couplings are avoided. In addition to the actual plug-in connector housing, the ferrite sleeves can also be arranged on a cable manager of the plug-in connector. 
     In one alternative embodiment, the plug-in connector housing and/or a retainer and/or a cable manager consists at least partially of a ferrite material or contains ferrite material. It is thus possible, for example, for a cable manager to consist completely of a ferrite material, the core pairs then being passed through said cable manager in their respectively associated segment. As an alternative, the ferrite sleeves can be encapsulated by injection molding in the plug-in connector housing. It is also possible to admix ferrite powder to the plastic injection molding material. 
     A common-mode filter arrangement preferably takes place in the case of a plug-in connection both on the plug side and on the socket side, but the respective design of the common-mode filter arrangement may be different. 
    
    
     
       The invention will be explained in more detail below with reference to a preferred exemplary embodiment. In the figures: 
         FIG. 1  shows a schematic illustration of a common-mode inductor on a printed circuit board for the first and second contacts, 
         FIG. 2  shows an exploded illustration of a plug-in connector (prior art), 
         FIG. 3  shows an exploded illustration of a plug-in connector with a ferrite sleeve holder, and 
         FIG. 4  shows an exploded illustration of a ferrite sleeve holder with ferrite sleeves. 
         FIG. 5  is a schematic diagram of the alternative plug-in connector  1  shown in  FIG. 3 . 
     
    
    
       FIG. 2  shows an exploded illustration of a plug-in connector  1 . The plug-in connector  1  comprises a plug-in connector housing  2 , a printed circuit board  3 , a retainer  4  and a cable manager  5 . In the example illustrated, the plug-in connector housing  2  is in the form of a socket housing having various latching and insertion means. The plug-in connector housing  2  is formed with a shielding plate  6  on the side faces. The printed circuit board  3  is populated with a set of second contacts  7  on its front side and with a set of first contacts  8  on its rear side, said first contacts  8  being in the form of insulation displacement contacts. In each case one contact  7  is connected to a contact  8 . The printed circuit board  3  is then inserted into the plug-in connector housing  2 . In the process, cylinder pins  9  of the plug-in connector housing  2  pass through holes in the printed circuit board  3 , with the result that the plug-in connector housing  2  and the printed circuit board  3  are adjusted and fixed with respect to one another. The contacts  7  in the form of RF contacts then protrude into an opening which is accessible from the front side of the plug-in connector housing. Then, the retainer  4  is pushed over the contacts  8  of the second set and latched to the plug-in connector housing  2 . For this purpose, the retainer  4  is formed with latching tabs  10  on the end side and has continuous openings  11  for the insulation displacement contacts  8 . Furthermore, the retainer  4  is formed with two latching hooks  12 , which serve the purpose of latching with a cable manager  5 . The cable manager  5  is essentially square and has an opening in the center, around which a cylindrical attachment  14  is arranged. The opening extends from the rear side continuously to the front side, a guide cross  17  being arranged in the opening and dividing the opening into four segments. In this case, an associated core pair of a data cable is guided in each segment. As regards the further design of the plug-in connector, express reference is hereby made to WO 02/15339. 
       FIG. 1  now shows a schematic illustration of a first embodiment of the common-mode filter arrangement for a plug-in connector shown in  FIG. 2 . Two associated insulation displacement contacts  8  are illustrated on the printed circuit board  3 , by means of which contacts  8  contact is made with the cores of a core pair. The two insulation displacement contacts  8  are electrically connected to an SMD component  22  via in each case one conductor track  20 ,  21 , said SMD component  22  comprising a common-mode inductor  23  having a ferrite ring  24 . The SMD element  22  is connected to the associated RF contacts  7  on the other side of the printed circuit board  3  via conductor tracks  25 ,  26  and through-platings (not illustrated). As a result, the common-mode signal on the core pair is reduced in pairs, with the result that this core pair represents a lesser interference source for adjacent plug-in connectors. In the exemplary embodiment illustrated, the common-mode inductor  23  is illustrated only for one core pair. It goes without saying that, in the case of an RJ45 socket as shown in  FIG. 2 , four common-mode inductors  23  are used for the four core pairs. Alternatively, the plug-in connector housing  2  or the retainer  4  and/or the cable manager  5  may also consist of ferrite material or contain ferrite material. 
       FIG. 3  shows an alternative plug-in connector  1  in the form of a plug, the plug-in connector housing having a two-part design and comprising an upper part  31  and a lower part  32 , which can be latched to one another. For this purpose, the upper part  31  is formed with latching hooks  33 , which engage in latching openings  34  in the lower part  32 . A cable manager  35  is arranged in the lower part  32  and ensures defined guidance of the cores  28  of a data cable  50  to first contacts  29 , which are coupled to the RF contacts  30  of the plug. Arranged behind the cable manager  35  is a ferrite sleeve holder  36 , which is used for holding four ferrite sleeves  37 . The cores  28  to be connected are in this case guided in pairs through the ferrite sleeve  37  and then in the cable manager  35 . The ferrite sleeve holder  36  is in this case designed such that the four ferrite sleeves  37  do not come into contact with one another, with the result that feedback of magnetic currents is avoided. The ferrite sleeve holder  36  is in this case not fixed separately to the housing, but is held by the cores  28  or upper and lower parts  31 ,  32  pressing on one another. The ferrite sleeve holder  36  preferably consists of plastic. 
     As can be seen in  FIG. 4 , the ferrite sleeve holder  36  has a two-part design and comprises a front part  38  and a rear part  39 . The front part  38  comprises a base body  40 , which has bays  41 , in each case offset through 90° with respect to one another. These bays  41  accommodate the ferrite sleeves  37 . Furthermore, the base body  40  has cylindrical attachments  42  having clamping protrusions  43 . As can be seen in  FIG. 3 , a ferrite sleeve  37  is fixedly clamped between four cylindrical attachments  42  with clamping protrusions  43 . In this case, the front part  38  and the rear part  39  have a virtually identical design. In order to connect the front part  38  and the rear part  39  to one another, in each case two cylindrical attachments  42  have journals  44 , which enter an opening  45  in the opposite cylindrical attachment  42 . Furthermore, the base body  40  also has holding journals  46 . 
       FIG. 5  shows a schematic illustration of the alternative plug-in connector  1  shown in  FIG. 3 . The plug-in connector  1  includes the upper housing part  31  and the lower housing part  32 . The cable manager  35  is arranged in the lower part  32 . Ferrite sleeves  37  are arranged behind the cable manager  35 . The plug-in connector  1  also includes first contacts  29  and second, RF contacts  30 . A second contact  30  corresponds to each first contact  29 . The first contacts  29  are DC-connected to their corresponding second contacts  30 . Contact is made with a plurality of core pairs  28  of a symmetrical data cable  50  by means of the first contacts  29 . Two first contacts  29  are correspond to each core pair  28 . An electrical contact is produced with contacts of a complementary plug-in connector by means of the second contacts  30 . Cores  28  of the cable  50  are guided through the sleeve  37  to the manager  35  to the contacts. 
     LIST OF REFERENCES 
     
         
           1  Plug-in connector 
           2  Plug-in connector housing 
           3  Printed circuit board 
           4  Retainer 
           5  Cable manager 
           6  Shielding plate 
           7  RF contacts 
           8  Insulation displacement contacts 
           9  Cylinder pins 
           10  Latching tabs 
           11  Openings 
           12  Latching hooks 
           14  Cylindrical attachment 
           17  Guide cross 
           20  Conductor track 
           21  Conductor track 
           22  SMD component 
           23  Common-mode inductor 
           24  Ferrite ring 
           25  Conductor track 
           26  Conductor track 
           30  RF contacts 
           31  Upper part 
           32  Lower part 
           33  Latching hooks 
           34  Latching openings 
           35  Cable manager 
           36  Ferrite sleeve holder 
           37  Ferrite sleeve 
           38  Front part 
           39  Rear part 
           40  Base body 
           41  Bays 
           42  Cylindrical attachments 
           43  Clamping protrusions 
           44  Journals 
           45  Openings 
           46  Holding journals