Improvements in and relating to electrical connectors

Abstract

 An electrical plug (1) for high frequency data transmission comprises at least a termination block (5) and a wire management element (7) arranged for connection to a cable (10). The cable has a plurality of wires (11) each with a conductor (21), and the wire management element is arranged so that it receives and guides the wires into a series of open ended channels (63) within the termination block. The termination block is arranged to receive a plurality of contacts (6) and is arranged to retain the contacts in a first position in the block and a second position in the block. Each contact is moveable from the first position (see 20F Figure 20A) to the second position (see 20J in Figure 16 and Figure 20B), and arranged so that in the first position the wires may be inserted through the channels, and in the second position each contact is held by the termination block in electrical contact with a conductor. The plug further comprises a housing (2) arranged to receive the wire management element and the termination block when the contacts are in the second position.

Description

[0001] The present invention relates to electrical connectors for making a disconnectable connection for computer networks and telecommunications systems, where the operating speed is greater than 100Mhz.

[0002] It is known to provide disconnectable electrical connections by means of plugs and sockets. Examples of such plug and socket system are the RJ11 and the RJ45 systems. The RJ45 plug and socket is typically used for making connections to high speed data networks. While there are disadvantages associated with using the RJ45 connector system, most of the computer equipment currently available is provided with a compatible socket, and likewise there has been a considerable investment in networking infrastructure using the RJ45 system. Hence, if new systems are to be interoperable with older systems, it is preferable that they should use the same connection system.

[0003] A disadvantage of known electrical connections for low voltage electrical signals, such as the RJ1 and the RJ45 systems, is that they were not designed for operating at high frequencies. It is difficult to maintain the separation of the individual plug pin contacts and of the wires connected to them so as to avoid crosstalk between adjacent pairs of contacts. Once it has arisen, such crosstalk requires elaborate measures to provide a cancelling signal. Such elaborate measures frequently are only effective over a small frequency range, and hence a plug and socket arranged to operate at a particular frequency may be unsatisfactory at a different frequency, or a plug that will work in one design of socket, will not function satisfactorily with an alternative design of socket. Further, due to slight differences in connecting wires to plugs, can give large uncontrolled variations in performance. In addition to this, since the wires are normally contained within a cable sheath, that is relatively inflexible, movement of the cables in use may easily cause movement of the wires within the plug, and hence adversely affect the performance of a plug fitted to a socket

[0004] Typically known communication connector plug designs have a housing with wires un-guided from an exit point of a cut end of a cable outer sheath around the wires to where the wires are arranged into a linear array in an internal nose part of the plug housing where a metal contact plate component is pushed down through the wires outer sheath creating a insulation displacement connection (IDC) connection or alternatively the metal contact plates may be arranged to create an insulation piercing connection. To obtain a higher electrical performance, typically known plugs will use an internal wire management system usually based around a separate moulding through which the various wires pass around or through before being terminated at the nose end of the plug with an IDC connection to the contact plates. To obtain improved performance it is necessary to keep the pairs of wires separated and guide them in such a way as to minimize the crosstalk arising between the pairs within the plug. A particular problem is that due to the arrangement of the terminals defined in internationally accepted standards, the connection of the wires to the terminals is different at each end of a cable. At one end of a cable the green wire pair is separated to either side of the blue wire pair as they locate into their termination point on the connector. At the opposite end of the cable, while the green wire pair still needs its wires to sit either side of the blue wire pair, the positions of the green and blue wire pairs have now swapped sides relative to the orange and brown wire pairs. This means that at one end of the cable the plug will have the green wire pair sitting at the top of the plug, relative to the contact plates, and at the other end of the cable the plug will have the blue wire pair sitting on the top of the plug, relative to the contact plates (as described below with reference to the specific embodiment). This straddling of the green pair over the blue pair and the added complication of both ends having a variation in wiring geometry to begin with, coupled with the need to comply to a wiring standard does not help with the crosstalk problems associated with high frequency signal connectors, which inevitably gives rise to crosstalk between the green and blue wire pairings, as well as various disturbances and further crosstalk between all the other wire pairings. Known internal wire management systems do not address in a simple and effective manner the problem of enabling the different arrangement of connections at each end of a cable.

[0005] From US patent number US 6,080,007 (Dupuis et al, assigned to Hubbell) it is known to provide a connector fox communications systems, such as an RJ45 plug, with a front and a rear sled, the sleds being arranged to constrain by means of conduits the individual wires from a cable as they enter the plug. A problem with the arrangement of US '007 is that the sleds arranged in two parts are not physically connected and as such the wires in between can become located in a position that may be not the ideal orientation for the electrical characteristics that the plug has been designed to achieve. It also means the front sled might come loose and disassemble itself from the plug assembly thus far. The wires exiting the first sled are layered in two levels and then guide themselves unhindered into one single linear array of wires in the second sled, this also gives an area of uncontrolled wire location and as such an area that can make the assembly process inconsistent. The mention of a lamination and bonding to hold the wire assembly in the ideal position to help the assembly process indicates a problem that has to be overcome by means of an external removable aid to keep the wires in position either before and after wiring. Also, as the whole wire assembly is still loose and in two sled pieces before assembling it into the plug outer housing means that the wires could still move and become dislodged and change positions relative to those that are desired or those that were intended when first assembled together. The wires would also need to be trimmed to length at this stage in order to fit inside the outer housing and as they are not fixed in position fully, they could move out of position and might push back through the sleds and become too short. There would be no direct easy way to check this once assembled into the outer housing either, as the outer housing will obstruct the view of the inner wire arrangements to some degree and give some doubt as to whether the wires are as they should be. This would not become apparent until product testing at which point the whole patch-cord assembly would have to be scrapped. The rear sled or front sled also do not appear to be reversible and as such do not address the issue of the green blue wire orientation as the wires exit the cable at either end of a cable. There is even mention that the assembly operators have scope and can therefore presumably vary the assembly process within their knowledge of the 'art' of plug assembling. This does not appear to describe a reliable, repeatable and scientifically engineered process or part if it relies on 'art', skill and judgement for its assembly. It also negates an earlier statement in the patent that the construction of the plug gives a 'fixed', 'uniform' and 'predetermined' construction and because of this, similar electrical properties.

[0006] From US patent application number US 2002048990 (Marowsky et al) it is known to provide a wire aligner arranged so that two of the four twisted pairs may be situated in each of a central upper and lower spaces. However the wire aligner of U '990 is such that the wires from a cable are separated onto two horizontal planes. A disadvantage of this arrangement is that it requires either a subsequent change in level or the insulation piercing contacts must be of different vertical lengths to ensure a contact face of each contact is at the correct height when the piercing portion of the contact has made contact with the respective wire conductor. The wires at the front of the wire aligner are also not held down in position and therefore could twist, bend, become misplaced or push back through the wire aligner when assembling the whole assembly into the outer housing before termination. It also means the wires need to be trimmed to the correct length before they are fixed in their final positions in the plug which might change as the plug is assembled and therefore make the plugs more difficult to assemble or even possibly render the parts as scrap. Front and rear wire aligners are not connected and as such might also let the wires become misplaced. The outer sheath of the cable is not catered for in any way in this design and as such could and might become twisted and pulled back revealing the twisted pairs leaving them open to each other and possible misalignment again.

[0007] From US patent application number US 2005037672 (Caveney et al, assigned to Panduit) a similar wire 'load bar' to that shown in US '990 is shown retained inside a housing by clip fit features on a separate insert. That insert also provides clip fit features to retain a cable boot. A disadvantage of the arrangement shown in US '672 is that the wires have to be trimmed before insulation piercing contacts have been set to a position where they have made contact with the wire conductors and secure the wires in place. This means they could become dislodged during the outer housing assembly process and or the act or crimping the IDC contacts down into the wires themselves. It also does not address the issue of the green & blue pair cross over issue at either end of the cord, and it requires no less than three differently sized contact plates to perform the insulation displacement of the wires due to the multi levels at which the wires emerge from the 'conductor divider'.
The 'Entrant Barbs' that are shown sticking out of the 'load bar', are inserted into the cable and act merely as either a location device, in the embodiment of the single barb, to keep the 'load bar' centrally located. Then, in the double prong embodiment, as a rotational stabilising device, which can also sit astride a cross-filler, but the geometry of either barb embodiment does not add any additional shielding or separation to the cable pairs as they are merely a small cylindrical forms.

[0008] According to the present invention, there is provided an electrical plug for high frequency data transmission comprising at least a termination block and a wire management element arranged for connection to a cable, the cable having a plurality of wires each with a conductor, the wire management element being arranged so that it receives and guides the wires into a series of open ended channels within the termination block, the termination block arranged to receive a plurality of contacts and to retain the contacts in a first position in the block and a second position in the block, each contact moveable from the first position to the second position, and arranged so that in the first position the wires may be inserted through the channels, and in the second position each contact is held by the termination block in electrical contact with a conductor and wherein the plug further comprises a housing arranged to receive the wire management element and the termination block when me contacts are in the second position.

[0009] A benefit of the invention is that it is possible to achieve a desired electrical performance characteristic of the plug by managing the wires internally through the mechanical components of the plug.

[0010] A benefit of the contact plates being retained to the termination block is that the termination block and contact plates together form a sub-assembly that can be easily handled, whereas the individual contact plates are of such a small size that not only are they difficult to handle and orientate. A further benefit is that when the contact plates are initially partially pressed into the termination block such that they are held securely in the first position the arrangement facilitates a quick and trouble free termination of the wires in the plug.
A benefit of a housing to receive the separate termination block and wire management element, allows the wire management element to be orientated with respect to the termination block and hence to a plug housing, at one of two positions 180 degrees apart while maintaining an external configuration and or profile of the plug. Hence by using the housing the use of alternative configurations of the termination block and the wire management element is facilitated so as to enable the accommodation of different wire order at each end of a patchcord.
A further benefit of the housing is that the plug may more easily be arranged to comply with the dimensional and functional requirements of the internationally accepted standards, such as that for RJ45 connectors or other future standards.

[0011] Preferably the wire management element and the termination block are arranged to be mounted in a first configuration where a first face of the wire management element faces in the same direction as a contact face of the termination block having the contacts, and a second configuration where the first face faces in the opposite direction to the contact face.
A benefit of the internal wire management element and the termination block being arranged so that they can be mounted together in two alternative configurations, when one is rotated through 180 degrees, is that the same wire management element and termination block can be used at each end of a RJ45 plug patch cord.

[0012] Preferably the wire management element comprises at least a plurality of passages, each passage arranged for receiving at least a wire, the passages arranged so that the wires passing through the wire management element pass through the passages.
A benefit is that every time the connector is assembled it will achieve the desired wire mapping arrangement at the nose end of the plug, in a repeatable and consistent manner.

[0013] Preferably the wire management element is arranged to be mounted to the termination block and further arranged so that when the wire management element and the termination block are mounted together, the wires are arranged to pass from the wire management element to the termination block without crossing each other.
Preferably the wire management element is arranged to resiliently clip to the wire termination block.
A further benefit of the invention is that support is provided so as to guide the wires in a specific geometric manner which keeps the wires in positions such that the plug meets the required crosstalk performance repeatably.
A further benefit of the invention is that a consistent and repeatable assembly method is provided, which is not reliant on the expertise of the plug assembly operator but enables a consistent build quality regardless of who performs the task.

[0014] Preferably the wire management element further comprises first resilient limbs arranged to grip an external surface of the cable.
A benefit of the first resilient limbs is that they assist with guiding the cable into the wire management element, and being resilient permit the position of the cable to be easily adjusted relative to the wire management element.

[0015] Preferably the plug further comprises a cable boot arranged to resiliently clip to the wire management element, the cable boot arranged to resiliently support the cable at the rear of the plug.
A benefit of the support provided by the cable boot is that anticipated flexing of the cable as it leaves the plug does not cause the cable to bend tighter than a preferred minimum bend radius of the cable.

[0016] Preferably the Cable Boot is tapered to give a reduced flexibility as it passes up closer to the main plug housing, the most flexible end being at the very rear end tip or entry point of the cable.

[0017] Preferably the cable boot clips over an external latching face of the first resilient limbs.
A benefit of the cable boot clipping over an external latching face of the first resilient limbs is that at least one of the cable grip features of the wire management element is moved to a position where it is arranged to grip an outer sheath of the cable and hence the cable is then be held securely while the wires are terminated in the termination block.

[0018] Preferably the wire management element further comprises a second pair of resilient limbs having internal faces facing each other and arranged to grip the cable and external faces facing away from each other and each having a protrusion arranged to act against an internal face of the housing when the wire management element is inserted into the housing, so as to urge the internal faces towards each other so as to securely grip the cable.
A benefit of the wire management element comprising a plurality of cable grip features is that cable grips may be moulded into the wire management element, and arranged so that their effectiveness is independent of any actions of a person assembling the connector.

[0019] Preferably the wire management element is arranged to be retained to the housing by a first resilient latch.
A benefit of the wire management element being retained to the housing by a latch is that assembly is facilitated. It also allows a second embodiment of the plug assembly in as much as allowing the plug to be assembled with or without the cable boot part being present should this so be desired at any stage.

[0020] Preferably the cable boot is arranged to be retained to the housing by a second resilient latch.
Preferably the housing is also arranged to latch the cable grip features of the first resilient limbs of the wire management element
A benefit of a second latch is that the assembly may be made secure. A benefit of latching the cable grip is that it can not become disengaged from the cable without removal from the housing.

[0021] Preferably the first and second latches comprise protrusions on lateral external faces of the wire management element and the cable boot respectively, and each or the latches engage with latching faces from an internal surface of the housing.
A benefit of the latches engaging from an inside of the housing is that removal of the housing is difficult without excessive force being applied so as to damage the housing or the wire management element or the cable boot.

[0022] Preferably the plug further comprises an electrically conductive outer shielding member, the outer shielding member arranged to fit at least partly around the housing.
A benefit of the shielding member is that better isolation may be achieved from electrical interference external to the plug.

[0023] Preferably the outer shielding member is provided with a resilient limb, the limb arranged to protrude into an inner space with the housing.
Preferably the resilient limb is arranged to make electrical contact with the outer shield of the braid or foil of the cable.
Preferably the outer shielding member further comprises at least a resilient lateral face to a side of the housing, the lateral face arranged to make electrical contact with a shielding member of a socket to which the plug may be mounted.
A benefit of the outer shielding having a resilient limb making electrical contact with the cable shield or braid is that electrical continuity of the shielding is achieved.

[0024] Preferably a longitudinal axis along a centre line of the cable where the cable enters the plug is co-incident with an axial axis through a centre line of the wire management element and is co-incident with a plane through a centre line of the wires in the termination block.
A benefit of the common axes is that there is as minimum deformation of the wires as they enter and terminate in the connector. A further benefit is that the minimum deformation minimises any effect on a signal transmitted along the wires. This also facilitates the ability for the wire management element and termination block assembly to rotate through 180 degrees for assembly in either position.

[0025] The wire management element may also be provided with a conductive coating in a second embodiment.
Preferably this conductive coating is metallic. This conductive coating may cover all or only part of the wire management element depending on the performance requirements.
A benefit of a conductive coating is that this will enable a plug to alter its electrical characteristics in order to achieve the desired properties required.

[0026] Preferably at least one contact plate is provided with an elliptical hole.

[0027] A benefit of the hole through at least one plate is that the hole reduces the cross sectional area of the plate resulting in a reduction of coupling between that plate and an adjacent plate, and hence this results in a reduction of cross talk between said adjacent contact plates.

[0028] Preferably the housing further comprises a resilient limb arranged to overlaps an operating lever for releasing a resilient latch provided to retain the plug to a socket.
A benefit of the resilient limb is that a risk of the operating lever snagging on other cables when a cable with the plug attached is pulled through other cables is reduced.

[0029] Preferably the resilient limb is provided with an enlarged portion facing at least partly to the rear of the plug.
A benefit of the enlarged portion facing rearwardly is easy operation of the operating lever when the connector is mounted to a high density patch panel.

[0030] Preferably the plurality of wires are arranged as twisted pairs of wires, the twisted pairs being separated from each other within and along the cable, by a substantially cruciform divider, and wherein the wire management element is arranged to co-operate with the divider so as to maintain the separation of the twisted pairs as they enter the wire management element.
A benefit of the separation of the twisted pairs being maintained as the wires leave the cable and enter the wire management element is that a risk of crosstalk between the pairs of wires is minimised.

[0031] Preferably each passage is arranged to receive a pair of wires from the cable, each passage being arranged to receive at least a partial twist along a portion of the pair of wires.
A benefit of each passage being arranged to receive at least a partial twist along a portion of the pair of wires within the passage is that a length of untwisted pairs is minimised, hence a risk of crosstalk between pairs of wires is minimised.

[0032] Preferably at least one passageway.is open to one side of the wire management element at an end abutting the termination block.
A benefit of the passageway being open to one side, is that a pair of wires in that passageway may more easily be correctly positioned tautly within the wire management element.

[0033] Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is an exploded perspective view from a first side of a first embodiment of an electrical connector according to the invention;

Figure 2 is an exploded perspective view from a cable entry end and a second side of the first embodiment of an electrical connector shown in Figure 1;

Figure 3 is an exploded perspective view from the cable entry end and the first side of the first embodiment of an electrical connector shown in Figure 1;

Figure 4 is a perspective view of an "A side" of a wire management element of the first embodiment shown in Figure 1, viewed from the cable entry end, and with wires inserted but with a cable not shown for clarity;

Figure 5 is a perspective view of a "B side" of the wire management element shown in Figure 4 of the first embodiment shown in Figure 1, viewed from the cable entry end, and with wires inserted but with a cable not shown for clarity,

Figure 6 is a perspective view of an "A side" of the wire management element of the first embodiment shown in Figure 1, viewed from the termination end, and with wires inserted but with a cable not shown for clarity;

Figure 7 is a perspective view of a "B side" of the wire management element of the first embodiment shown in Figure 1, viewed from the termination end, and with wires inserted but with a cable not shown for clarity;

Figure 8 is a sectioned perspective view of the "A side" of the wire management element shown in Figure 4;

Figure 9 is a sectioned perspective view of the "B side" of the wire management element shown in Figure 5;

Figure 10 is a perspective view of the "A side" of the wire management element as shown in Figure 4, viewed from the cable entry end, but with wires absent;

Figure 11 is a perspective view of the "B side" of the wire management element as shown in Figure 5, viewed from the cable entry end, but with wires absent;

Figure 12 is a perspective view of the "B side" of the wire management element as shown in Figure 7, viewed from the termination end, but with wires absent;

Figure 13 is a perspective view of the "A side" of the wire management element as shown in Figure 6, viewed from the termination end, but with wires absent;

Figure 14 is a perspective view of the "A side" of the wire management element as shown in Figure 4, with a cruciform cable divider shown entering the cable entry, but with the wires and cable omitted for clarity;

Figure 15 is the same perspective view as Figure 14, but with the cruciform cable divider fully inserted into the wire management element;

Figure 16 is a perspective view of a sub-assembly of the wire management element viewed from the "B side" mounted to the termination block and the cable boot of the first embodiment shown in Figure 1, with a cable and wires fully inserted through the wire management element;

Figure 17 is a perspective view of the sub-assembly of Figure 16 being inserted into a plug body sub-assembly;

Figure 18 is the same perspective view as Figure 17 but with the sub-assembly of Figure 16 fully inserted into the plug body sub-assembly ready to be inserted into a socket;

Figure 19 is a diagrammatic representation of the wiring of the plugs at each end of a patch cord using a plug according to the present invention, and Figures 19A and 19B show the orientation for each end of the patch cord of the wire management element shown in Figure 1;

Figure 20 is a side view of a section viewed along arrow 20X in Figure 1, the section taken through the electrical connector when fully assembled in a plane coincident with a side of a contact plate;

Figure 20A is an enlarged scrap view of a portion of Figure 20 showing the connector in a partially assembled state;

Figure 20B is an enlarged scrap view of a portion of Figure 20 showing the connector in a second partially assembled state corresponding to that shown in Figure 16;

Figure 21 is a perspective view of a second embodiment of the invention, similar to the first embodiment, but without a cable boot; and

Figure 22 is a perspective view of a third embodiment of the invention, similar to the first embodiment, but without an outer shielding element.

[0034] From Figures 1, 2 and 3, exploded perspective views of a first embodiment of an electrical connector in the form of an electrical plug 1 according to the invention are shown. The electrical plug 1 has a body 2 having a closed front end 3 and an open rear 4, into which may be inserted along an axial direction parallel to arrow 1B, a termination block 5 having a plurality of contacts 6, and a wire management element 7 having a plurality of passages 8. In use, before insertion of the termination block and wire management element, wires 11 of a multi-core cable 10 are threaded through a cable entry 2C in a boot 9 and then through passages 8 in the wire management element 7 and then into and through termination block 5.
When the wires are in the desired positions in the passages 8 the termination block is mounted to the wire management element.
The termination block is provided with clips 51, 52, 53 and 54 (more clearly seen in Figures 2 and 3) which as shown in Figures 1, 2 and 3 engage with retention features 71, 72, 73, and 74 respectively of the wire management element, so as to retain the termination block to the wire management element when the wires have each been threaded through one of the passages 8 and through their respective open ended channel in one of wire receiving locations 63 in the wire management element. In use, it may be found convenient to have a reasonable length 1L of wire, such as say 25 or 50mm protruding a front face 62 the termination block as the connector is assembled (see also Figure 20A), so that a person assembling the connector may pull on an exposed end of each individual wire so as to ensure that it is correctly positioned in its correct channel 23 within the passages 8 and wire receiving locations 63 and that there is no unnecessary slack.
Each of the wire receiving locations 63 is an open ended channel within the termination block, the channel being open at both front face 62 and transverse plane 16J (see Figures 16 and 20A). Each of the open ended channels has an outlet at front face 62, through which an end of a wire within the channel may protrude.
Once the person assembling the connector is satisfied that each of the wires is correctly routed in its passageway or channel 23, contacts 6 are then moved in the direction of arrow 1C from a first position 20F (see Figure 20A) where the wires may be inserted into a wire receiving portion 61 of the termination block to a second position 20J (see Figures 16 and Figure 20B) where each contact pierces an insulation 22 covering of the wire 11 inserted through a particular wire receiving location 63 associated with each contact, so as to make electrical contact with a conductor 21.
An electrically conductive outer shielding member, shield 12 is provided to wrap around the plug housing body 2 at recess region 13. The shield 12 is mounted to the body 2, by moving in the direction of arrow 1A, so that a resilient limb, tab 14 of the shield passes through a slot 15 into an interior space 16 within the plug body. The shield 12 is provided with resilient limbs 17 and 17', which are shaped to protrude at 18 and 18' from each side of the body 2. The resilient limbs are arranged so that when the plug is inserted into a socket 100 (see Figure 18), the shield makes electrical contact with a corresponding shielding element 102 of the socket. Hence, the interconnection between the cable and the socket is fully shielded to prevent undesirable electro-magnetic interference affecting the transmission of a signal through the interconnection.
Figure 1 is an exploded perspective view from a first side 1S of the electrical plug 1, while Figure 2 is a similar view, but from an end having a cable entry 2C and a second side 2S of the electrical plug 1. Figure 3 is a further similar view from the end having the cable entry 2C and the first side 1S of the electrical plug 1. From these views it can be seen that the boot 9 is symmetrical, having sides 1S" and 2S" being identical to each other and also sides 3S" and 4S" being identical to each other, and hence the boot maybe rotated through 180 degrees with respect to the rest of the plug components without affecting the assembly. The boot 9 provides support to the cable 10 as it leaves the plug body 2, so as to reduce a risk that the cable is damaged at the point of entry/exit to the plug body 2.

[0035] Since the termination block is a separate part from the wire management element, the wire management element may in a particular embodiment, if desired for particular performance requirements, be plated in order to change the performance of the plug, without the plating affecting the electrical insulation between contacts or wires. Such plating provides the wire management element with a metallic conductive coating. Such a conductive coating may be arranged to cover all surfaces of the wire management element, or alternatively the coating may be arranged to cover only a part of the surface. As an alternative to plating, since the wire management element does not have any electrical insulation requirements, an electrically conductive material may be used, such as a metal diecasting or a conductive plastics material.

[0036] Figure 16 shows a perspective view of a sub-assembly 121 of the wire management element viewed from the "B side" mounted to the termination block and the cable boot of the plug 1, with a cable 10 and wires 11 fully inserted through the wire management element 7. The wires 11 have been trimmed flush with face 62 of the terminal block 5. Each wire 11 is located in a particular wire receiving location 63, such that good electrical contact is made with the respective contact 6 when the contact is in the second position as shown in Figure 16.

[0037] When mounted to the wire management element 7, the termination block 5 closely abuts the wire management element at transverse plane 16J. As the wires pass from the wire management element to the termination block they are constrained to a linear array, where each wire is abutting its neighbour. Hence when the wire management element and the termination block are mounted together, the wires pass directly from the wire management element to the termination block without crossing each other.

[0038] From Figure 17 a perspective view of the sub-assenably 121 of Figure 16 being inserted into a plug body housing sub-assembly 122 of the body 2 and the shield 12. Although plug body sub-assembly 122 is shown with the shield 12 already fitted, it may be more convenient to fit the shield to the plug body after the sub-assembly 121 has been inserted in to the plug body 2 by moving in the direction of arrows 1X, 17X'.

[0039] The boot 9 has two protruding outwardly facing clips 91 and 92 on opposite sides 1S" and 2S" respectively. The outwardly facing clips 91 and 92 are supported by wire management element retention feature 171 and 172 respectively. The outwardly facing clips 91 and 92 are a second resilient latch to retain the cable boot to the housing assembly 122. Wire management element 7 also has outwardly facing clips 161 and 162 on opposite sides 1S" and 2S" respectively. The outwardly facing clips 161 and 162 are a first resilient latch retaining the wire management element to the housing sub-assembly 122. The outwardly facing clips 91 and 92 and 161 and 162 engage with slots 291, 292, 261 and 262 respectively as the sub assembly 121 is inserted fully into the plug body 2 to securely retain the termination block 5, the wire management element 7 and the boot 9 to the body 2.

[0040] The first resilient latches 161, 162 and second resilient latches 91, 92 comprise protrusions on lateral external faces of the wire management element 7 and the cable boot 9 respectively, and each of the latches engage with latching faces 261, 262 and 291,192 respectively from an internal surface of the housing 2. Hence the latches are protected from accidental release or damage.

[0041] From Figure 18 electrical plug 1 is shown with the sub-assembly 121 fully inserted into the plug body sub-assembly 122 and positioned ready to be inserted in a direction 18P into a socket 100. The socket 100 has a shielding element 102 arranged to make electrical contact with shield 12 of the plug. The shielding element 102 is preferably earthed. The socket 100 has a receiving portion 101 arranged to receive a plug, such as plug 1. The receiving portion 101 has a latching face 106 arranged to co-operate with resilient latch 116 on the plug body 2 so as to retain the plug in the socket when the plug has been fully inserted, so that each of the contacts 6 make electrical contact with a corresponding contact within socket aperture 108 (the corresponding contacts are not visible in Figure 18) of the socket 100.
A enlarged pad 117 is resiliently mounted to the body 2, so as to facilitate a user disengaging latch 106/116 so as to remove the plug from the socket. This resilient limb is arranged to overlap an operating lever 118 for releasing resilient latch 106/116 provided to retain the plug to a socket is particularly useful where adjacent plugs are closely spaced in a high density patch panel. The arrangement of pad 117, where the enlarged portion faces at least partly to the rear of the plug, effectively extends arm 118 of the latch 116, and at the same time assists in protecting the arm 118 from snagging and hence suffering damage when the patch cable is withdrawn from a patch panel.

[0042] From Figure 18, it can be seen that the cable boot is the same width 18W as the body 2. The width 18W is such that the plug 1 may be inserted into the socket aperture 108 which has a width 18S. Hence, the connector may be mounted to compatible sockets with a minimum of space between them. Hence the connector may be used in a high density patch panel, such as used in a blade server installation.

[0043] From Figure 20 a side view of a section viewed along arrow 20Y in Figure 1, the section taken through the electrical plug 1, when fully assembled, in a plane coincident with a side of a contact plate. It can be seen that a longitudinal axis 20X along a centre line of the cable 10 where the cable enters the plug is co-incident with an axial axis through a centre line of the wire management element 7 and is co-incident with a plane 21P through a centre line of the wires 11 in the termination block 5.
The common axis 20X ensures that there is as minimum deformation of the wires as they enter and terminate in the connector. Since the wire management element 7 and the termination block 5 abut at transverse plane 16J, and since a mating profile of the wire management element and the termination block is symmetrical about the longitudinal axis 20X, the wire management element and termination block assembly maybe mounted to each other in either one of two relative orientations, 180 degrees apart from each other.
Hence a benefit of an electrical plug according to the present invention is that since the wire management element and the termination block may be assembly in either one of two alternative configurations the plug may easily be used at each end of a patch cord.

[0044] Figures 20A and 20B, are enlarged scrap views of a portion of Figure 20 showing the plug 1 in a first and a second partially assembled state respectively. In Figure 20A the termination block 5 is shown with the contacts 6 in a first position 20F, where they permit the wires to be inserted as shown through their respective open ended channel in the termination block 5, so that the wires protrude approximately a length 1L beyond the face 62. When, a person assembling the plug is satisfied that the wires have been pulled equally taut so that they lie fully within the passages or channels of the wire management element, the contacts 6 may be pressed to a second position 20J shown in Figure 20B, where the nearest contact 6 can be seen to have pierced the insulation 22 of the wire associated with that contact, so that the contact makes electrical contact with its conductor 21. The contacts have an elliptical hole 163 to reduce a capacitative effect between adjacent contacts.

[0045] Hence the wires are terminated before the excess wire protruding the termination block is cut or trimmed off flush with face 62. The electrical connection with each wire is made before the excess wire is trimmed off.

[0046] In Figure 20A, the contact 6 can be seen to be an interference fit at 141 and 142, and hence retained in the first position 20F.

[0047] In Figure 20B, the contact plate 6 can be seen to abut the termination block at 143 and 145. This abutment provides a visual indication that the contact plates have been moved fully to the second position 20J. The contact plates are retained in the second position by protrusions 146 and 147 engaging a surface 144 of the particular wire receiving location 63 corresponding to the particular contact 6. Hence in the second position 20J each contact 6 is held by the termination block 5 in electrical contact with a conductor 21.

[0048] Figure 20B shows the plug 1 in a second partially assembled state corresponding to that shown in Figure 16. In this state, the sub assembly may be visually inspected to ensure the wires are correctly located in their respective channels or passageways in the wire management element. This sub-assembly forms a substantially rigid assembly, and as such may be handled carefully without concern that the cable or wires will be dislodged from their desired positions.

[0049] In applications where support is not required for the cable, the boot may be omitted as shown in Figure 21, where a perspective view of a plug 500, a second embodiment of the invention, similar to the first embodiment 1 in all respects but without a cable boot is shown. Plug 500 has a wire management element 507 mounted with a body 502 and shield 512 arranged as in the case of plug 1 to provide a means of disconnectably connecting a patch cord 510 to a socket Patch cord 510 has four twisted pairs of wires separated by a cruciform longitudinal divider 521. Plug 500 is arranged to provide the same benefits of plug 1 other than that the cable is not supported by the plug. Hence, plug 500 is suited to applications where support is provided to the cable by a cable management system associated with a patch panel.

[0050] Figure 22 is a perspective view of a plug 600, a third embodiment of the invention, similar to the first embodiment 1, in all respects but without an outer shielding element. Plug 600 is suited to applications where the shielding provided by the shielding element is not required.

[0051] Figures 4 to 15 inclusive show different perspective views of the wire management element 7. In each view the uppermost side is identified, being either an A Side or a B Side. In some of the views, such as Figures 8 and 9, the views are partly sectioned, but for clarity cross-hatehing has been omitted from the sectioned faces. Figures 4 to 9 inclusive show the wires 11 passing through the plurality of passages 8 in the wire management element 7. From Figures 8 and 9, it can be seen that as the wires pass through the wire management element 7 the relative heights or displacements of the wires from the plane 21P changes so as to permit the wires to cross over each other as required. The cruciform divider 150 runs the length of the twisted pair multi-core cable 10, so as to provide spaces 15A, 15B, 15C and 15D to each accommodate a single twisted pair of wires 11A, 11B, 11C and 11D respectively. Prior to inserting an end 151 of the cruciform divider 150 in the axial direction 1B between prongs 165 and 166, the cable 10 is rotated in the direction of arrow 14R about its longitudinal axis so that the twisted pair of wires in the space 15A are those that are required to be inserted into the Y passage 191, and the twisted pair of wires that are in the space 15B are those that are required to be inserted into the parallel passage 192 visible in the B side, and the twisted pair of wires that are in the space 15C are those that are required to be inserted in the side passage 194 on side 2S' and the twisted pair of wires mat are in the space 15D are those that are required to be inserted in the side passage 193 on side 1S'.

[0052] Open passages 201 and 202 permit the wires of a cable to be inserted through some of the passages 8 in the wire management element before others. The open passages 201 and 202 are open to one side, the B side of the wire management element at end face 205. End face 205 is arranged to closely abut end face 206 of the termination block 5 at the transverse plane 16J when the wire management element is mounted to the termination block, Hence, when the cable is inserted into cable entry 7C between arcuate gripping surfaces 181 and 182, one pair of wires 11A is fed through passage 191, 196, 197 and another pair of wires 11B is fed through passage 192, while the remaining two pairs of wires 11C and 11D may initially pass out of the wire management element from slots 203 and 204. This has a benefit of allowing a person assembling the connector to ensure the first two pairs of wires are correctly positioned, before having to concentrate on the outer two pairs 11C and 11D of wires. To position the outer pair 11C the wires may be pulled down through open passage 201 so that they are aligned with the other wires. Pair 11D is likewise pulled down through open passage 202. When all wires are aligned, so that their centre lines are parallel as shown in Figure 6, the wires protruding the wire management element all lie on the plane 21P. In this state the wires are in the correct planar arrangement for insertion into the termination block 5.

[0053] Hence the wire management element is arranged to co-operate with the cruciform separator 150 so as to maintain separation of the individual twisted pairs of the twisted pair communications cable 10 as they leave the cable and pass through the wire management element 7.

[0054] From Figure 9, it can be seen that the wires 211 and 212 in the passageway 202, 204 have a partial twist 276 as at the cross sectional plane 9X wire 212 is on the outside of wire 211, but at the termination block end of the wire management element the wire 211 is on the outside of wire 212.

[0055] It may be preferable for the other wires to also have at least a partial twist through 180 degrees as they pass along their respective passages. For some of the passages, for example passage 192 it may be preferable for the pair of wires to have a full twist through 360 degrees, or if the orientation of the wires as they leave the cable is such that a greater twist is required to achieve a desired wire order of the wires at 211 to 218 at planar array 219 when the wires lie on plane 21P.

[0056] In the wire management element 7, each of the passages is open at either the termination block end adjacent to and from face 205 or at the cable entry end adjacent to and from the prongs 165 and 166 to either side A or side B of the wire management element. Further passages 203 and 204 are open to sides 1S' and 2S' along apart of the length of the wire management element.

[0057] The wire management element has a plurality of cord grip features to ensure the cable is retained securely to the connector in normal use without a risk of excessive axial force being applied to the wire and contact interface which might affect the electrical performance of the connector. The cord grip features comprise opposed first resilient limbs each having an arcuate gripping surface 181 and 182 which have sharp teeth 180 arranged to grip the cable sheath 130 which forms an external surface of the cable, without crushing the cable. Crushing the cable would have a detrimental effect on the data transfer performance of the connector cable assembly.

[0058] Additional opposed gripping surfaces 183 and 184 are internal faces that are provided to further support the cable when it has been mounted to the wire management element. The gripping surfaces 183 and 184 are mounted on resilient limbs being resilient arms 185 and 186 respectively, which have protrusions or ramps 187 and 188 respectively, arranged so that when wire management element 7 is inserted into a housing body 2, the ramps 187 and 188 urge the resilient arms inwards, and hence cause the cord gripping surfaces 183 and 184 to grip and support the cable more tightly. The gripping surfaces 183 and 184 assist in preventing movement of the cable within the wire management element so as to ensure that a reliable electrical connection is maintained.

[0059] When the cable boot 9 is mounted to the wire management element 7, the clip fit features 91 and 92 of the cable boot, by sliding over external latching faces of retention features 171 and 172, assist in maintaining the grip of the arcuate cable gripping surfaces 181 and 182 on a cable. Hence, a sub-assembly comprising the cable fitted to the wire management element and with a cable boot in place, is suitably robust to be handled without damage to the electrical connections in the termination block.

[0060] By way of example, the use of a plug according to the invention, such as that shown and described above, is described with reference to use with a known twisted pair cable, such as a Cat 5e or a Cat 6 or 6A computer networking cable.
Hence, in use, to connect the plug 2 to a twisted pair cable 10, an assembler takes a cut end of the cable and threads the cable through a boot 9. The cable sheath 130 is stripped back to reveal approximately 100mm of wires. The stripped wire length does not have to be precisely measured at the start of the build, as the wires pass through the inner plug assembly and are then trimmed off once the wires have been finally fixed by the action of crimping the contact plates into the wires. The cruciform separator / filler 150 is cut so that it protrudes by approximately 2mm beyond the end of the sheath. The exposed length of the twisted pair of wires are separated and untwisted as necessary.
Preferably where the passage is suitable for receiving the wires when twisted, maintaining the twist for this portion of a passage will enhance the performance of the connector. One such portion of passage 191 is portion 195 before the passage divides into the two single wire portions 196 and 197. Another such portion is passage 192 (it should be noted that in Figures 4 to 9, most of the wires have been shown in an untwisted state for the draughtsman's convenience).
The position of the Green & Blue pairs relative to the Orange and Brown pairs and the orientation the wire management element, must then be established according whether the plug is to be wired as an "End A" plug or an "End B" plug which is used for a wiring scheme known as TIA-568B.
For example for an "End A" plug, an assembler would orientate the cable so that the green pair will be on top (position 15A in Figure 15) and the orange and brown pairs below (position 15B in Figure 15), away from the assembler. The orange and brown pairs (15C and 15D respectively) will be first partly laced through the wire management element so that the ends of the wires protrude the face 2S' and 1S' respectively of the wire management element.
The green pair of wires is then laced into the upper channel 191 of the 'Y' shaped channel on the top A side of the wire management element and the blue pair is laced into the B side straight channel 198 so that all these wires protrude the front face 205 of the wire management element 7.
The wire management element is then eased along the wires until the outer sheath 130 of the cable is up as far as the wires channel entrance and the cruciform separator 150 is located correctly in the gap between the prongs 165, 166 of the wire management element. It may be advantageous to do this by pulling through some slack first onto the side areas of the two side looped over wires to allow the others to move freely, then pulling through the looped wires last.
The two pairs of wires protruding the sides 1S' and 2S' are then pulled taut and twisted so as to ensure that the wires may be pulled through the respective open passages 201, 202 so that these wires also protrude the front face 205.
Once the wires are correctly located in the wire management element as shown in Figures 4 to 9, and the cable sheath and cruciform separator in also correctly located, the boot 9 is slid along the cable 10 so that it clips on to the wire management element so as to secure the cable in position relative to wire management clement (as shown in Figure 16).

[0061] The termination block 5 may now be mounted to the wire management element 7, In the configuration shown in Figures 1, 2, and 3 where the plug is assembled as an "End A" plug configuration, the termination block assembly of the termination block 5 and the contacts 6 is positioned such that the contact plates are on top, facing the same way as side A of the wire management element, and the hooks 51,52,53 and 54 are facing the wire management element. The wires are laced through the termination block assembly in the same order as they exit the wire management element. The termination block assembly is then clipped onto the front nose of the wire management element so that the hooks 51, 52, 53 and 54 engage retention features 71, 72, 73 and 74 respectively.

[0062] Once the termination block sub-assembly has been clipped to the wire management element, the wires in the open passages 201 and 202 are constrained from moving out of the opening of their respective passages at the face 205, by their respective channels in the termination block.

[0063] Hence the passages and wire channel are arranged to constrain each of the wires from before the wires leave the outer cable sheath to the point of termination. The passages and wire channel geometry is arranged to optimise the separation of wire pairs. The assembler may easily verify visually that all the wires are in the correct position relative to one another since they protrude the termination block face 62 and if necessary the assembler, at this stage, may pull or otherwise adjust any of the wires to achieve the desired routing of the wires through the wire management element. The contact plates may now be moved down from the first position where the contacts are raised so that the wires may be inserted into the termination block to the lower second position where the contacts each pierce the insulation of the wire in the respective wire receiving locations 63 immediately below each of the contacts, such that the contacts each make an electrical contact with the conductor of the respective wires. Since a height 20H of the termination block is less than that of a standard plug, a custom tool is preferably provided to ensure the contacts are all moved correctly to the second position, without a risk of applying excessive force that might cause the contacts to damage the termination block where they abut at 143, 145.
The assembler may now trim off excess wire (length 1L of Figure 20A) protruding the termination block, by using a sharp cutting tool to slice off the excess wires. The assembler may easily verify visually that there are no stray strands of wire coming from the ends of any of the wires.

[0064] Hence it can be seen that the termination block part and wire management element are each arranged so that when the contact plates are moved to a second position where they are each in electrical contact with a conductor of a wire, the wires are axially constrained.
Such an arrangement, ensuring the wires are constrained before they are trimmed provides an improved consistency and repeatability of plug assembly. Hence repeatable performance characteristics may be achieved by plugs according to the present invention.

[0065] The outer housing sub-assembly of the body 2 and shield 13 may now be assembled to the sub-assecably 121. The assembler preferably holds the boot firmly, and pushes the housing 2 in the direction of arrow 17X, 17X' of Figure 17 over the sub-assembly and onto the boot 9 so that they clip securely together. In a particular embodiment, an audible click may be heard as the boot, the wire management element 7 and the housing 2 clip together, thus providing audible feedback to the assembler. Since the boot has already operated the cable gripping features, a risk that the assembly may be damaged by handling or assembling the body 2 to the sub-assembly 121.

[0066] If an assembler has not correctly positioned the wires within the wire management element, then due to the close fit of the body 2 over the wire management element 7, it would not be possible to assemble the body over the wire management element.

[0067] This final assembly acts on two aide arms 187, 188 on the wire management element to further grip the outer sheathing of the cable and therefore holding it in place along with the grip feature 181,182 located at the rear of the wire management element activated earlier when the cable boot was fitted. The outer housing once fitted locks onto both the cable boot part and the wire management element, creating a very secure and tightly fitting cable retention detail The plug essentially has to be destroyed in-order to disassemble it.

[0068] To make a complete patch cord, the process must be repeated to assemble a second plug to the other end of the cable. However, for a normal patch cord, it is necessary that the second end is connected to the plug as an "End B" configuration.

[0069] This is similar to the "End A" described above, except as illustrated by Figure 19, the relative configuration of the wires, the wire management element and the termination block is different.

[0070] From Figure 19 a diagrammatic representation of the wiring of the plugs 901 and 902 at each end of a patch cord 900 using a plug, such as plug 2 described above, according to the present invention. The wiring diagram shown is for a wiring scheme according to industry standard TIA-568B, for straight through patch-cords.
The patch cord cable 903 has an orientation of wires that effectively differs from one end 905 of the single piece of cable to the other end 906, relative to the plug body 901 and 902 respectively and desired wiring layout. The plugs 901 and 902 are viewed along a direction of arrow 19V and 19V' respectively. The cable has twisted pairs 911, 912, 913 and 914, each with two wires 921 and 931, 922 and 932, 923 and 933, and 924 and 934 respectively. The twisted pairs are separated from each other by a cruciform divider 909, 909' which extends along the length of the cable. The cruciform divider extends between each of the twisted pairs to an inside of the cable sheath 908. Hence a relative position of each of the twisted pairs is maintained along the length of the cable. As shown by the diagrammatic representation of the cable 903, the position of the 911 and 913 pairs will in effect "swap sides" relative to the 912 and 914 pairs as they exit the cable at the ends 906 and 907. This affects the way the plug is built.
In the plug of the present invention, the wire management element 907 and 907' (Figures 19A and 19B) is reversible to allow for this change in relative position of the twisted pairs at the ends 906 and 907 of the cable. In order to accommodate the change in relative position, the route taken by the pairs 911 and 913 is changed by mounting the wire management element 907 so that at one end 906 the wire management element 907 is mounted in a first configuration where a first face 973, the A side, faces in the same direction 19D as a contact face 940 of the termination block 949 having the contacts 941 to 948 inclusive (only some shown for clarity), and at the other end, end 906' the wire management element 907' is mounted in a second configuration where the first face 973 faces in the opposite direction 19F to a direction 19E the contact face 940'. At the end 906' a second face 970, the B side of the wire management element 907' faces in the same direction 19E as the contact face 940' having the contacts 941' to 948' inclusive (only some shown for clarity). (Note, all labelled items at the end 906' marked with a dash correspond to the like numbered items at the other end 906.)

[0071] Hence the wire management element 907 has been rotated through 180 degrees in the direction of arrow 19T about a longitudinal axis 19V along a centre line of the cable entering the wire management element from the orientation at end 906 relative to end 906'with respect to the termination block 949.

[0072] Hence the wire management element 907 guides and constrains the wires 921 and 931, 922 and 932, 923 and 933, and 924 and 934 along the passages from within a cable at a rear end 974 to a substantially linear array 951 to 958 inclusive (although only two labelled in Figure 19B) at a front end 975. The termination block is arranged to be retained to the wire management element by resilient clip means so that it abuts the front end, and so that the wires in the array 951 to 958 enter the termination block as shown at plug 901 in the array labelled from 1 to 8. The wires 923 and 933 of pair 913 which are shown in Figure 19 as being at a contact side of the cable, having been splayed by divided passage 971 to either side of the wires 921 and 931 of pair 911 are guided into positions 953 and 956 and hence to positions 3 and 6.

[0073] While at end 906', where the wires 921 and 931 are now at a contact side of the cable, wire management element 907' is arranged to guide the wires 921 and 931 alongside each other through the constant width passageway 972 to positions 4' and 3'.

[0074] Hence alternative wiring arrangements are easily provided at each end of a twisted pair cable, while maintaining full control of each wire within the plug.

[0075] The arrangement of the embodiments described herein provide an electrical plug particularly arranged for high frequency data transmission. An example of such high frequency data transmission would be that envisaged in computer network cable standards CAT6 and CAT6A. To consistently achieve such high data transmission speeds it is necessary to control and guide the individual wires of each twisted pair from when they exit the sheathed cable to where they are connected to the plug contacts in a repeatable manner. The termination block and a wire management element are arranged to do this. The wire management element in receiving and guiding the wires into the series of open ended channels within the termination block ensures a repeatable path for each wire for every termination of a cable.

Claims

1. An electrical plug (1) for high frequency data transmission comprising at least a termination block (5) and a wire management element (7) arranged for connection to a cable (10), the cable having a plurality of wires (11) each with a conductor (21), the wire management element being arranged so that it receives and guides the wires into a series of open ended channels (63) within the termination block, the termination block arranged to receive a plurality of contacts (6) and to retain the contacts in a first position (20F) in the block and a second position (20J) in the block, each contact moveable from the first position to the second position, and arranged so that in the first position the wires may be inserted through the channels, and in the second position each contact is held by the termination block in electrical contact with a conductor and wherein the plug further comprises a housing (2) arranged to receive the wire management element and the termination block when the contacts are in the second position.

2. An electrical plug as claimed in claim 1, wherein the wire management element and the termination block are arranged to be mounted in a first configuration where a first face (973) of the wire management element faces in the same direction (19D) as a contact face (940) of the termination block (949) having the contacts, and a second configuration where the first face faces in the opposite direction (19F) to the contact face.

3. An electrical plug as claimed in any of the preceding claims wherein the wire management element part (907) comprises at least a plurality of passages (8), each passage arranged for receiving at least a wire, the passages arranged so that the wires passing through the wire management element pass through the passages.

4. An electrical plug as claimed in any of the preceding claims wherein the wire management element (907) is arranged to be mounted to the termination block (949) and further arranged so that when the wire management element and the termination block are mounted together, the wires are arranged to pass from the wire management element to the termination block without crossing each other.

5. An electrical plug as claimed in any of the preceding claims wherein the wire management element further comprises first resilient limbs (181,182) arranged to grip an external surface (130) of the cable.

6. An electrical plug as claimed in any of the preceding claims wherein the plug further comprises a cable boot (9) arranged to resiliently clip to the wire management element, the cable boot arranged to resiliently support the cable at a rear (4) of the plug.

7. An electrical plug as claimed in claim 6 when dependent on claim 5, wherein the cable boot clips over an external latching face (171, 172) of the first resilient limbs.

8. An electrical plug as claimed in any of the preceding claims wherein the wire management element further comprises a second pair of resilient limbs (185,186) having internal faces (183,184) facing each other and arranged to grip the cable and external faces facing away from each other and each having a protrusion (187, 188) arranged to act against an internal face af the housing when the wire management element is inserted into the housing (2), so as to urge the internal faces towards each other so as to securely grip the cable.

9. An electrical plug as claimed in any of the preceding claims, wherein the wire management element is arranged to be retained to the housing by a first resilient latch (161, 162).

10. An electrical plug as claimed in any of the preceding claims, wherein the cable boot (9) is arranged to be retained to the housing by a second resilient latch (91, 92).

11. An electrical plug as claimed in claims 9 and 10 wherein the first and second latches comprise protrusions on lateral external faces of the wire management element and the cable boot respectively, and each or the latches engage with latching faces (261, 262 and 291, 192) from an internal surface of the housing.

12. An electrical plug as claimed in any of the preceding claims wherein the plug further comprises an electrically conductive outer shielding member (12), the outer shielding member arranged to fit at least partly around the housing (2).

13. An electrical plug as claimed in claim 12, wherein the outer shielding member is provided with a resilient limb, the limb arranged to protrude into an inner space with the housing.

14. An electrical plug as claimed in any of the preceding claims wherein a longitudinal axis along a centre line of the cable where the cable enters the plug is co-incident with an axial axis through a centre line of the wire management element and is co-incident with a plane through a centre line of the wires in the termination block.

15. An electrical plug as claimed in any of the preceding claims wherein the wire management element is provided with a conductive coating.

16. An electrical plug as claimed in claim 15 wherein the conductive coating is metallic.

17. An electrical plug as claimed in claim 15 wherein the conductive coating is arranged to cover all surfaces of the wire management element.

18. An electrical plug as claimed in any of the preceding claims wherein at least one contact plate is provided with an elliptical hole.

19. An electrical plug as claimed in any of the preceding claims, wherein the housing further comprises a resilient limb arranged to overlap an operating lever (118) for releasing a resilient latch (116) provided to retain the plug (1) to a socket (100).

20. An electrical plug as claimed in claim 19 wherein the resilient limb is provided with an enlarged portion (117) facing at least partly to the rear of the plug.

21. An electrical plug as claimed in any of the preceding claims, wherein the plurality of wires are arranged as twisted pairs of wires, the twisted pairs being separated from each other within and along the cable, by a substantially cruciform divider (150 or 521), and wherein the wire management element (at 165 and 166) is arranged to co-operate with the divider so as to maintain the separation of the twisted pairs as they enter the wire management element (7).

22. An electrical plug as claimed in any of the preceding claims when dependent on claim 3, wherein each passage (8 at 191, 192, 193 and 194) is arranged to receive a pair of wires from the cable (10), each passage being arranged to receive at least a partial twist (276) along a portion of the pair of wires.

23. An electrical plug as claimed in any of the preceding claims when dependent on claim 3, wherein at least one passageway (201, 202) is open to one side (B) of the wire management element at an end (205) abutting the termination block (5).

Drawing