Patent Publication Number: US-7905015-B2

Title: Method for terminating a telecommunications cable

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 11/552,168 filed Oct. 24, 2006, (now U.S. Pat. No. 7,448,920), which is a divisional of U.S. patent application Ser. No. 10/853,566 filed May 24, 2004 (now U.S. Pat. No. 7,150,657), which claimed priority to U.S. Provisional App. No. 60/472,779 filed May 23, 2003. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a wire lead guide which serves as a guide for wires between the end of the cable and a connector and a method for terminating a communications cable. In particular, the present invention relates to wire lead guide for arranging the individual twisted pairs of wires exiting the end of a telecommunications cable, their connection to a connector and the method of use of the wire lead guide in order to improve performance of the cable/connector assembly. 
     BACKGROUND 
     The development of the Category 6 standard (ANSI/TIA/EIA-568-B.2-1) and its subsequent wide acceptance by the telecommunications industry has raised the transmission requirements for electrical signals in telecommunications cables to a higher level than ever. Category 6 is a performance classification for twisted pair cables, connectors and systems which is specified up to 250 MHz. 
     In many installations, in particular office buildings and the like, telecommunications cables are installed behind walls or in the plenum ceiling and floor spaces. These cables are typically terminated at a first end in a patch bay close to servers or other networking equipment and terminated at a second end at a receptacle in proximity to the user. At both ends the individual wires emerging from the end of the cable are spliced into the back of an appropriate connector with the front side of the connector being exposed to provide easy access for the insertion and removal of patch cables. In order to test the installed cables to assess whether or not they meet the specifications as dictated by the applicable standards, a testing equipment is attached to the front of the connector located at the patch bay and the front of the connector located at the receptacle. Measurement of the performance of length of cable, therefore, includes not only the length of cable but also the connectors through which access to the cable is gained. 
     As higher transmission frequencies give rise to complex changes in the behaviour of the various components, not only the performance of the individual components, in this case the cable and the two connectors, is important but also the manner in which these components are interconnected. A number considerations should be taken into account when installing telecommunications cables in order to ensure that they will meet the requisite testing specifications following installation. In particular, the cable termination on the back of the connector is an important factor and the conduction of an installation in a casual manner can lead to a significant degradation of performance. 
     One important electrical characteristic by which the performance of a telecommunications cable is measured is Near-End-Crosstalk, or NEXT. As is well known in the art, crosstalk is the undesired coupling from signal carrying wire to a collocated signal carrying wire. Crosstalk gives rise to undesirable interference which can severely affect transmission performance. For its part, NEXT is a measurement of crosstalk between two wire pairs of wires and is measured as the difference in signal strength between the interfering pair and the interfered pair. NEXT is directly affected by the manner in which the cable is terminated, and arises when the wires of two pairs are crossed. Crossing of wires can arise due to a number of reasons including failure to take appropriate care during installation or physical forces brought to bear on the cable or connector, for example during the installation of other cables. 
     Additionally, failure to take appropriate care when stripping the jacket from the length of cable as well as untwisting the twisted pairs can create a loop which can also affect performance. Therefore, installation of the cable on the back of each connector becomes very sensitive to the manner in which the installation is carried out by the installer. 
     SUMMARY OF THE INVENTION 
     In order to address the above and other drawbacks, the present invention provides for a method for terminating a telecommunications cable where the cable comprises a plurality of twisted pairs of wires arranged in a generally parallel relationship to a common axis, each of the twisted pairs having an exposed end portion. The method comprises the steps providing an interconnection module comprising a pair of contacts for each of the twisted pairs, aligning the end portions and interconnecting each of the aligned end portions with a corresponding pair of conductive contacts. The aligning step comprises arranging the end portions such that when connected to the contact pairs, the twisted pairs remain uncrossed. 
     There is also described a wire lead guide for isolating the end portions of a plurality twisted pairs of wires where the twisted pairs arranged in a generally parallel relationship to a common axis and distributed around the common axis. The guide comprises a guide body and a plurality of non-intersecting passageways through the body. Each of the passageways is comprised of an entrance and an exit. The end portions of one of the twisted pairs are inserted through a corresponding one of the passageways. The passageways isolate the twisted pairs of wires from one another. 
     There is also disclosed a connector assembly for terminating a communications cable where the cable comprises a jacket encasing a plurality of twisted pairs of wires and wherein an end portion of each of the twisted pairs is exposed. The assembly comprises an interconnection module comprised of a plurality of pairs of contacts and adapted to interconnect with the end portions of the twisted pairs and a wire lead guide comprised of a guide body and a plurality of non-intersecting passageways through the body. The end portions are inserted through a corresponding one of the passageways prior to interconnection with a corresponding one of the pairs of contacts. 
     Additionally, there is disclosed a connector assembly for terminating a category 6 communications cable where the cable comprises a jacket encasing four twisted pairs of wires and wherein an end portion of each of the twisted pairs is exposed. The assembly comprises an interconnection module comprised of four of pairs of terminals, the pairs of terminals adapted to interconnect with the end portions of the twisted pairs. The assembly exhibits between subsequent installations a range of alien cross talk at 100 MHz between pairs of twisted pairs of less than 1.000 mV/V. 
     Furthermore there is disclosed a method of installing a category 6 communications cable, the cable comprising a jacket encasing four twisted pairs of wires and wherein an end portion of each of the twisted pairs is exposed. The method comprises the steps of providing an interconnection module comprising a pair of contacts for each of the twisted pairs, aligning the end portions; and interconnecting each of the aligned end portions with a corresponding pair of conductive terminals. The method exhibits over subsequent installations a range of alien cross talk at 100 MHz between pairs of twisted pairs of less than 1.000 mV/V. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is an exploded view (from the front) of a connector in accordance with an illustrative embodiment of the present invention; 
         FIG. 2  is an exploded view (from the rear) of a connector in accordance with an illustrative embodiment of the present invention; 
         FIG. 3  is a perspective view of a communications cable having four pairs of twisted pair conductors in accordance with an illustrative embodiment of the present invention; 
         FIGS. 4   a  and  4   b  are cross sectional views of the cable of  FIG. 1  taken across lines  4 - 4 ; 
         FIG. 5  is a perspective view (from the rear) of an assembled connector in accordance with an illustrative embodiment of the present invention; 
         FIG. 6  is a schematic diagram illustrating the manner in which twisted pairs may become crossed during installation; 
         FIG. 7   a  is a perspective view of a wire lead guide in accordance with an illustrative embodiment of the present invention; 
         FIG. 7   b  is a side view of a wire lead guide in accordance with an illustrative embodiment of the present invention; 
         FIG. 7   c  is a side view (from above) of a wire lead guide in accordance with an illustrative embodiment of the present invention and  FIG. 7   d  is a top plan view of a wire lead guide in accordance with a two piece illustrative embodiment of the present invention; 
         FIG. 8  is a top plan view of a wire lead guide in accordance with a first alternative illustrative embodiment of the present invention; 
         FIG. 9   a  is a top plan view of a wire lead guide in accordance with a second alternative illustrative embodiment of the present invention; 
         FIG. 9   b  is a bottom plan view of a wire lead guide in accordance with a second alternative illustrative embodiment of the present invention and  FIGS. 9   c  through  9   f  provide a series of sectional views along lines  9   c  through  9   f  of the wire lead guide in  FIG. 9   a;    
         FIG. 10  is a schematic diagram illustrating the manner in which the twisted pairs should be arranged prior to insertion into the wire lead guide in accordance with an illustrative embodiment of the present invention; and 
         FIG. 11  is a perspective view of an assembled connector and cable with a wire lead guide interposed between the cabled end and the connector in accordance with an illustrative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS 
     Referring to  FIG. 1 , a connector assembly, generally referred to using the numeral  10 , for insertion into a patch bay or receptacle cover (both not shown) is disclosed. The connector assembly  10  is typically comprised of a front plate  12  having moulded into its front side  14  a socket  16  into which a patch cable having the requisite connector plug (both not shown) can be inserted. The front plate is typically manufactured from a dielectric material which is easily cast such as plastic. Moulded into the rear side  18  of the front plate  12  is a receptacle  20  for receiving a snap in interconnection module  22  and snap on cover  24 . 
     Note that although the socket  16  in the present illustrative embodiment is adapted to receive an RJ-45 type plug, sockets as in  16  having shapes adapted to receive other types of connectors are also within the scope of the present invention. Additionally, the connector assembly  10  could also be integrated into a patch panel (not shown) or form part of a connector assembly where the socket as in  16  is replaced by a BIX connector. 
     Referring to  FIG. 2  in addition to  FIG. 1 , the interconnection module  22  for the ANSI/TIA/EIA-568-B.2-1 standard is comprised of a series of eight (8) conductors as in  26  which are each terminated at a first end by a straight bendable portion as in  28  and at a second end by insulation displacement contact (IDC) terminals as in  30 , each having a bifurcated contact plate. Typically, the terminals  30  are arranged in two opposing parallel rows of four (4) terminals  30  each. 
     Referring to  FIG. 3 , a category 6 communications cable, in this case an Unshielded Twisted Pair (UTP) cable and generally referred to by the reference numeral  32 , is disclosed. Category 6 cables have evolved from the lower performance Category 5 and Category 5e cabling systems, and consist of four (4) pairs of 18 to 26 AWG gauge wires as in  34  manufactured from suitable conducting material such as copper. Each wire  34  is individually wrapped in a colour coded outer sheath  36 , typically manufactured from polyethylene (PE). As shown in  FIG. 3 , the two wires  34  of each pair are wound helically around one another to form the ubiquitous twisted pairs well known to persons of ordinary skill in the art. As stated above, twisted pairs significantly reduce the crosstalk which would otherwise arise as a result of the capacitive interference between two parallel transmission lines. Furthermore, as is also well known in the art, performance of a cable comprised of multiple twisted pairs of wires can be increased by varying the lay lengths of the twists between adjacent pairs (lay lengths typically range from 0.25 to about 1.5 inches for telecommunications cables). 
     Category 6 cables may include an isolating separator  38  between each of the four (4) pairs of wires  34 . The communications cable  32  also includes a cable jacket  40 , typically manufactured from polyvinylchloride (PVC). As will be clear on referring to  FIG. 4   a , the isolating separator  38  divides the chamber defined by the inner wall  42  of the cable jacket  40  into a series of four compartments as in  44 . Each compartment contains the two wires  34  belonging to one twisted pair. The isolating separator  38  is typically manufactured from a polymer material such as PVC or PE. The use of an isolating separator  38  further reduces cross talk thereby improving the performance characteristics of the cable. 
     Note that although the above illustrative embodiment makes reference to an Unshielded Twisted Pair (UTP) cable, the method and the wire lead guide could also be used in conjunction with other types if cables, for example Screened Twisted Pair (ScTP) cables or Shielded Twisted Pair (STP) cables in both round and flat configurations. 
     Referring back to  FIG. 2 , each bifurcated IDC terminal  30  has sharp opposed edges  46 . As is well known to persons of ordinary skill in the art, pressing a sheathed wire (as in  34  in  FIG. 3 ) into the bifurcation causes the sharp edges  46  to sever the outer sheath  36  thereby bringing the conductor as in  26  into electrical contact with the wire  34 . On assembly, the interconnection module  22  is inserted into the cover  24  such that each terminal  30  is arranged proximally to a corresponding slot  48  in the cover  24 . 
     Note that although the interconnection module  22  has been described hereinabove with reference to IDC type bifurcated terminals as in  30 , other types of contacts are also foreseeable for use in the present invention including soldered contacts or self-cutting contacts for use in “tool less” implementations. 
     Referring now to  FIG. 5 , once assembled, each slot  48  allows a wire as in  34  to be inserted between the sharp edges  46 . Typically individual wires and their corresponding sheaths  36  are inserted between the sharp edges  46  of the bifurcated IDC terminal  30  by means of a suitable tool which simultaneously removes any excess from the end of the wire  34 . A space  50  is provided for between the two rows of slots  48  to allow the wires  34  to be bent such that they may be pressed flat into the slots  48 . 
     As is well known to those of ordinary skill in the art, the sheaths  36  of each wire are colour coded in order to aid the installer during installation of cables onto the connectors. ANSI/TIA/EIA-568 provides for four standardised colours, that is blue, orange, green and brown, for colour coding the sheaths  36  of the individual wires  34 . As is also well known in the art, one wire  34  of each pair typically has a solid coloured sheath  36  while the second wire  34  of each pair has a white sheath  36  into which a stripe having the same colour as the other wire of the pair has been imbedded along the length thereof. 
     In fabricating a cable  32 , the twisted pairs are distributed around the core of the cable such that if the cable  32  is cut in cross section the order of the twisted pairs is predetermined. The order as defined by ANSI/TIA/EIA-568 when looking at a first end of the cable and proceeding clockwise is blue, orange, green and then brown, or alternatively when looking from the other end the reverse, i.e. blue, brown, green and then orange. In this regard, referring now back to  FIG. 4   b , the twisted pairs are referenced using the numerals I, II, III and IV. Applying the order as defined in ANSI/TIA/EIA-568 the colours could be assigned to each twisted pair in the following manner: I—blue, II—orange, III—green and IV—brown or alternatively (if viewed from the other end) I—blue, II—brown, III—green and IV—orange. 
     Referring again to  FIG. 5 , the wires  34  of each twisted pair are inserted into adjacent slots according to the requirements of the particular standard being implemented. ANSI/TIA/EIA-568B, for example, requires that twisted pair I (blue) be inserted in the two slots  48  located in the right lower quadrant of the snap on cover  24 , twisted pair II (orange) be inserted in the two slots  48  located left lower quadrant, twisted pair III (green) be inserted in the two slots  48  located left upper quadrant, and twisted pair IV (brown) be inserted in the two slots  48  located left lower quadrant. ANSI/TIA/EIA-568A, on the other hand, requires that the green and orange twisted pairs are reversed. 
     As stated above, NEXT is directly affected by the manner in which the cable  32  is terminated at that connector  10  and in particular NEXT can be introduced when the wires of different twisted pairs cross one another. Referring to  FIG. 6 , a schematic diagram of the various ways in which the wires  34  of a cable can be attached to a connector in accordance with ANSI/TIA/EIA-568A and 568B. Note that in  FIG. 6  reference numeral I indicates blue, II orange, III green and IV brown. Different termination sequences can be obtained depending on the standard desired (T568A or T568B) and the end of the cable which is being connected. As is apparent from the diagram, three out of four possibilities involve the crossing of the wires of different twisted pairs which can give rise to unwanted NEXT. 
     It should also be pointed out that NEXT is also affected by the manner in which the individual twisted pairs are terminated. For example, the steps of unjacketing a portion of the cable to reveal the twisted pairs and untwisting the pairs in order to insert them in the slots  48  creates a loop opening. Effort should be made to reduce this untwisting towards a minimum. 
     It will now be apparent from the above that in order to ensure that every installation meets the requisite performance requirements as laid down in the applicable standards, it is necessary to proceed during attaching the wires  34  to the connector  10  using a rigorous and systematic approach. Therefore, the provision of any methods or tools which ensure that the installer proceeds in a systematic fashion can serve to greatly improve the performance of the installed interconnection. 
     As stated above, NEXT is directly affected by the manner in which the cable is terminated, and arises when the wires of two pairs are crossed. Therefore, the ideal solution is to avoid crossing the pairs as the cable approaches the connector. Referring now to  FIGS. 7   a ,  7   b  and  7   c , in order to aid the installer during installation and prevent the crossing of the wires of different twisted pairs, regardless of the various configurations, a wire lead guide, generally referred to using the reference numeral  52 , is inserted between the connector  10  and the cable  32  in order to maintain an advantageous spacing between the twisted pairs. In this manner, the wire lead guide  52  reduces variations in performance which may be introduced as the result pour quality installation practices, by imposing a uniform and systematic way of terminating the cable  32  on the connector  10 . 
     In the present illustrative embodiment, the wire lead guide  52  comprises a guide body  53  and four (4) non-intersecting and generally parallel passageways  54  machined or cast, etc., through the upper surface  55  of the guide body  53  and into which the twisted pairs (not shown in  FIG. 7   a ,  7   b  or  7   c ) can be inserted. The guide body  53  can be fabricated not only from a suitable rigid dielectric material such as plastic, but also cast from a shielding material such as metal (e.g. zinc or aluminium), a composite material or a ferromagnetic material. The twisted pairs exit the guide body  53  via a series of exits as in  56  machined, cast, etc., at right angles to and intersecting the passageways  54 . Note that although the exits  56  are shown at right angles to the passageways  54 , in a given embodiment the exits  56  could be at an angle to the passageways  54  different from right angle, depending on the style of the 
     Referring back to  FIG. 5 , once the twisted pairs have been inserted through the passageways  54  in the guide body  53  and the wires of the twisted pairs are protruding out of their respective exits  56 , the wire lead guide is inserted into the space  50  located between the opposing rows of slots  48  in the cover  24 . It will be apparent now to one of ordinary skill in the art that the wires  34  of the twisted pairs which protrude from the exits are in position to intersect with the slots  48  into which they are then inserted. 
     Prior to inserting the twisted pairs through the passageways  54 , however, the twisted pairs should first be aligned in the correct straight sequence such that no crossing of the pairs occurs. Referring to  FIG. 10 , a schematic diagram of the conversion from a round sequence (for a round cable) to a straight sequence is provided. It should be noted that in  FIG. 10  the reference numeral  1  indicates the blue twisted pair,  2  indicates orange,  3  indicates green and  4  indicates brown. Depending on the configuration, by moving the twisted pairs in the directions indicated by the arrows the correct align of the twisted pairs to avoid crossing can be achieved. Notice that although twisted pairs  2  (orange) and  3  (green) are inverted between the T568A and T568B schemes, no crossing of the wires of different twisted pairs occurs. It is rather a transposition from their respective vertical position to a horizontal position. 
     As stated above, the use of a wire lead guide  52  is not applicable to only the round UTP cables as commonly used. The same wire lead guide  52  may be used with other cables including both the Screened Twisted Pair (ScTP) or Shielded Twisted Pair (STP), in both round and flat configurations. Use of the wire lead guide  52  is also not limited by colour coding of the twisted pairs nor their sequence within the cable. 
     Referring back to  FIGS. 7   a ,  7   b  and  7   c , when using the wire guide  52  the installation method consists of exposing the end of the cable to reveal the twisted pairs, arranging the twisted pairs according to the correct sequence as shown in  FIG. 10 , sliding the wire lead guide  52  onto the twisted pairs until the upper surface  55  of guide body  53  abuts the with the end of the cable jacket  40 , while maintaining the twisted pairs in the sequence according to  FIG. 10 . Once a sufficient amount of wire is exposed below the lower surface  58  of the guide body  53 , the twisted pairs are bent perpendicularly such that they pass through their respective exits  56 . 
     Still referring to  FIGS. 7   a ,  7   b  and  7   c , the four passageways  54  in the guide body  53  retain the twisted pairs in the correct sequence according to  FIG. 10 . The two raised abutments  60  serve to provide an increased separation between the external twisted pairs. The two dividing abutments  62  serve to better isolate the twisted pairs as they continue out of the exits  56  to their insertion points in the slots  48  thereby reducing cross-talk between them. Additionally, the outer edge of the dividing abutments  62  can be equipped with an angled flange  63  designed to snap fit with corresponding depressions ( 64  in  FIG. 2 ) formed in the cover ( 24  in  FIG. 2 ), thereby securing the guide  52 . The outer walls  65  serve to better isolate the twisted pairs from exterior interference, especially in the that event another connector is installed in close proximity. This external crosstalk is generally known in the art as “alien crosstalk”. 
     In an alternative illustrative embodiment the wire lead guide  52 , with suitable modifications, could be integrated directly into the cover  24  of the interconnection module  22 . 
     Additionally, the wire lead guide  52  is designed in such a way to reduce the distance between the unjacketed section of the cable and the connection. Referring to  FIG. 11 , a UTP cable  32  terminated by a connector  10  using the wire lead guide  52  is disclosed. The bending of the wires as in  32  in the exits  56  prevents the untwisting of the pairs through the wire lead guide  32  and underneath the cable jacket  40 . Therefore, the portion of each twisted pair which is untwisted may be reduced. Additionally, by forcing the wire lead guide  52  upwards such that the raised abutments  60  are inserted into a lower end  66  of the cable jacket  40 , the cable jacket  40  will be held close to the connector  10  thereby exposing a reduced end portion of each twisted pair. This, combined with reducing the untwisting of the twisted pairs at the connector, can greatly improve the return loss, another important electrical parameter. Additionally, the raised abutments can be bonded to the lower end  66  of the cable jacket  40  using a suitable adhesive or welding technique to further improve the mechanical strength of the assembly. Furthermore, a tubular sleeve (not shown) can be mounted on a portion of the exposed end portions of each twisted pair to ensure that the amount of untwisting is reduced. The sleeve could be manufactured, for example, from a material which shrinks when heated. 
     Ensuring that twisted pairs are all of similar length also improves the mechanical strength of the interconnection by distributing the pulling force that might otherwise be applied to one twisted pair to all twisted pairs. Furthermore, the lower end  66  of the cable jacket  40  could be fastened to the wire lead guide  52  in region of the raised abutments  60 , for example by using a suitable adhesive, thereby further improving the mechanical properties of the interconnection. 
     Referring now to  FIG. 8 , in a first alternative illustrative embodiment of the wire lead guide  52 , the passageways  54  are not aligned along the upper surface  55  of guide body  53  but rather are in a staggered configuration. This provides for an improved performance on one hand by reducing the length of the exposed end portions of the twisted pairs. 
     Referring now to  FIGS. 9   a  through  9   f , in a second alternative illustrative embodiment of the wire lead guide  52 , the non-intersecting passageways  54  do not run parallel to one another but rather slope towards their respective exits  56 . This provides for an improved performance on one hand by reducing the length of the exposed end portions of the twisted pairs and also by ensuring that the end portions of successive twisted pairs are not in parallel, which in turns reduces the coupling between twisted pairs. 
     In brief, the wire lead guide  52  allows for a systematic installation of a connector following simple steps thereby optimising the installation time, the performance of the electrical transmission parameters as well as the mechanical strength of the installation. 
     For category 6 installations, TIA standards dictate that any mated connection must have less than −54 dB of crosstalk between pairs of twisted pairs. This value represents a ratio between the disturbed pair and the disturbing pair of 2 mV/V. Considering the phase of the signal, this represents a total range of + or −2 mV/V, thus a total range of 4 mV/V. Since the total assembly of a plug, a jack and the termination must meet the standards requirements, it is necessary to control the variation of each of these components in order to ensure Category 6 performance in all installations. In order to guarantee a minimum standard of performance, it is important to determine the range (between the minimum and maximum) within which the amount of cross talk between any pair of twisted pairs varies. If the range within which one of the plug, jack or termination elements can be reduced, the performance can be increased, or, alternatively, the requirements on the other elements can be relaxed. 
     A series of comparative tests were performed on a series of like cables terminated by different installers in a conventional fashion and terminated using a wire lead guide  52 . Table 1 provides results for the cross talk between pairs of twisted pairs at 100 MHz where the cables were terminated in a conventional fashion by a number of different installers: 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 Pair 
                 1-2 
                 1-3 
                 1-4 
                 2-3 
                 2-4 
                 3-4 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Mean 
                 1.1350 
                 0.6900 
                 0.5840 
                 1.2419 
                 0.6094 
                 0.2239 
               
               
                 St. Dev. 
                 0.2136 
                 0.3177 
                 0.1986 
                 0.9315 
                 0.2132 
                 0.2083 
               
               
                 Range 
                 0.6446 
                 1.1780 
                 0.5754 
                 2.9248 
                 0.6089 
                 0.5330 
               
               
                 Minimum 
                 0.8780 
                 0.3224 
                 0.3023 
                 0.2843 
                 0.3858 
                 0.0333 
               
               
                 Maximum 
                 1.5226 
                 1.5004 
                 0.8777 
                 3.2091 
                 0.9947 
                 0.5663 
               
               
                 Count 
                 10 
                 10 
                 10 
                 10 
                 10 
                 10 
               
               
                   
               
            
           
         
       
     
     Table 2 provides results for the cross talk between pairs of twisted pairs at 100 MHz where the cables were terminated using a wire lead guide by a number of different installers: 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 Pair 
                 1-2 
                 1-3 
                 1-4 
                 2-3 
                 2-4 
                 3-4 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Mean 
                 1.1613 
                 0.5423 
                 0.5503 
                 0.6457 
                 0.4926 
                 0.1521 
               
               
                 St. Dev. 
                 0.1319 
                 0.1069 
                 0.2525 
                 0.1788 
                 0.0937 
                 0.0898 
               
               
                 Range 
                 0.5602 
                 0.3687 
                 0.9885 
                 0.6935 
                 0.3667 
                 0.2949 
               
               
                 Minimum 
                 0.7870 
                 0.3583 
                 0.1815 
                 0.3162 
                 0.3477 
                 0.0284 
               
               
                 Maximum 
                 1.3472 
                 0.7270 
                 1.1699 
                 1.0097 
                 0.7144 
                 0.3233 
               
               
                 Count 
                 20 
                 20 
                 20 
                 20 
                 20 
                 20 
               
               
                   
               
            
           
         
       
     
     In the above tables:
         Mean is the average cross talk in mV/V over the number of assemblies tested;   St. Dev. Is the standard deviation of the cross talk over the number of assemblies tested;   Range is the difference between the maximum crosstalk of all assemblies tested and the minimum cross talk of all the assemblies tested;   Minimum is the minimum cross talk of all the assemblies tested;   Maximum is the maximum cross talk of all the assemblies tested; and   Count is the number of assemblies tested.       

     Looking at the tables, it is apparent that over a large number of assemblies, the range in levels of cross talk between pairs of twisted pairs was decreased below 1 mV/V for those terminated using the wire lead guide, as opposed to those terminated in a conventional manner where the range was in one case close to 3 mV/V. 
     Other advantages are also associated with the wire lead guide  52 . For example, the wire lead guide  52  may be fastened to the connector assembly  10 , for example using a suitable adhesive or by the provision of a snap fitting, whereby it will provide additional mechanical support thereby improving cable retention and reducing negative effects related to the manipulation of the cable (for example, excessive bending). Given its compact dimension, the wire lead guide  52  can also be easily integrated into existing designs. The wire lead guide  52  may also be used on a connector assembly  10  during a mated performance qualification session, to eliminate the variance related to the installation. 
     A number of other variations to the wire lead guide  52  can also be foreseen. For example, referring to  FIG. 7   d , the wire lead guide  52  can be modified to be adapted to an already installed cable without removing the connections, for example by dividing the wire lead guide  52  longitudinally into two (or more) separate parts which clip together around the twisted pairs. 
     Additionally, the basic concept of the wire lead guide  52  can be easily adapted for use on a number of different connector types including those where the slots  48  are arranged in four straight pairs, two rows of two pairs, etc., by simply modifying the location of the exits  56 . Furthermore, it is not necessary that the passageways  54  be linearly aligned as illustrated in the figures. The passageways  54  could, for example, alternatively be arranged in a square pattern (i.e. with four twisted pairs in a 2 by 2 arrangement) provided the exits  56  are aligned in order to maintain the requisite arrangement. Also, the device can be used in conjunction with a termination (punch) tool or it can be adapted to a “tool-less” connector, where pressure ensures the contact. Regarding the tool-less connector, the wire lead guide could be integrated into the presscap (not shown), with the twisted pairs being arranged in the presscap such that, on mounting of the presscap to an interconnection module  22  equipped with self cutting contacts (not shown), interconnection is made between the individual conductors of each twisted pair and their corresponding contact. 
     Additionally, different materials could be used to optimise the performance of the wire lead guide  52 . For example, in order to provide enhanced electrical shielding properties it is possible to fabricate the wire lead guide  52  from a metallic material such as zinc or from a composite material containing some conductive material, such as ferromagnetic particles. 
     Although the present invention has been described hereinabove by way of an illustrative embodiment thereof, this embodiment can be modified at will without departing from the spirit and nature of the subject invention.