Improvements in and relating to electrical connectors

The present invention relates to insulation displacement connectors.

Insulation displacement connectors are known for connecting low voltage solid conductor insulated wire to the terminals of sockets. Most insulation displacement connectors require the use of a tool for termination of the wires to the connector, which can be inconvenient, and is slow as normally each wire has to be terminated individually. It is known to produce an insulation displacement connector where the wires are terminated without the use of a separate tool, the connector incorporating means for termination of the wires. However, a problem with known arrangements of such connectors is that high forces are required to achieve satisfactory termination, and hence an installer will resort to using a pair of pliers, for example, to ensure the termination is completed satisfactorily. This negates many of the benefits sought from using a connector incorporating means for termination of the wires.

Cables for terminating at such an insulation displacement connector normally have twisted pairs of wires to reduce interference. When terminating such a twisted pair to known insulation displacement connectors, it is necessary to untwist each of the twisted pair of wires before terminating them to the terminals. This is undesirable since an installer may untwist a longer length of wire than is necessary, hence increasing a risk of interference. Untwisting wires also is another operation, which increases the time to terminate a cable. For cables intended for high frequency data transmission, the wires are normally tightly twisted, which further increases the difficulty in untwisting the wires.

It is known from PCT application number WO 2004/077619 (Commscope Inc.) to provide an insulation displacement connector with an array of terminals, where a pair of terminals is provided for terminating each pair of wires, and one pair of terminals is separated from another by a substantial upstanding insulating portion of a connector body and to provide between the terminals of a pair, an upstanding tongue (see second wall with angled portion 27 of Figure 6 of Commscope). A disadvantage of Commscope is that the walls are such that it is necessary to untwist a substantial length of twisted pair before attempting to insert in the connector terminals.

According to an aspect of the present invention, there is provided an insulation displacement connector block for termination of a twisted pair cable, the connector block comprising at least two adjacent insulation displacement terminals arranged for

making electrical connection to insulated wires of a twisted pair of wires of the cable, the terminals each having an open mouth arranged to receive a single one of the wires, the open mouths facing a single entrance through which both wires are arranged to be inserted each to its own terminal, and an upstanding tongue between the terminals, the tongue having a substantially pointed end facing the entrance, the pointed end extending to the entrance and not beyond, the tongue dividing the entrance to provide two gaps.

A benefit of the tongue extending to the entrance and not beyond is that the wires are held centred above the pointed end, simultaneously as the pointed end opens a twist in the twisted pair of wires. The pointed end engages with the twisted pair between the two wires, so as to prevent both of the wires of the twisted pair moving to one side or another and rotating as the twisted pair is centred. Such movement and rotation may have the undesirable result of both wires of the twisted pair sliding down one gap.

Preferably each gap is smaller than a diameter of a single said insulated wire, and wherein a lip is provided on a side of the gap being so arranged to trap a wire, the lips being either on the tongue or on an opposed surface opposite each side of the tongue, or on both the tongue and one of or each of the opposed surfaces. A benefit of each gap being smaller than a diameter of a single said insulated wire is that it provides good wire retention of a laced pair and helps prevent this pair being dislodged as a subsequent pair is laced.

Preferably the lips are resiliently deflectable away from each other. A benefit of the lips being resiliently deflectable away from each other is that the wire may easily pass though a gap without excessive force.

Preferably the entrance is defined at its outer extent by an outwardly facing surface, the outwardly facing surface facing away from the mouth of the terminal, and wherein a width of the entrance at its outer extent is equal to or larger than twice the diameter of a single said insulated wire.

A benefit of the open entrance having width greater than twice a diameter of the wires, is that the entrance guides the twisted pair to a position centred above and in close proximity to the tongue.

Preferably the lips comprise an outwardly facing inclined surface arranged to funnel a wire into a gap.

A benefit of outwardly facing inclined surface is that, once untwisted, the wires are reliably guided through the gaps.

Preferably the outwardly facing surface further comprises a first outwardly facing surface and a second outwardly facing surface, the first and second outwardly facing surfaces being on different planes perpendicular to a direction of insertion of a wire into one of the terminals.

A benefit of outwardly facing surfaces being on different planes at different heights from a plane of the base, is that a twisted pair of wires is rotated slightly by impacting one slope before the other. This assists in enabling wires of pair to descend slightly staggered in time, and hence avoiding a sudden high insertion force as several wires pass through gaps simultaneously.

Preferably the tongue is resiliently deflectable to either side.

A benefit of the tongue being resiliently deflectable to either side is that it encourages one wire to snap in place before the other through the respective gap, reducing force needed compared to both wires snapping at the same time.

Preferably in use a twisted pair of wires is positioned above the entrance so that each of the wires are orientated substantially as required for making connection with the intended terminal, the twisted pair of wires is pushed downwards so as to contact the tongue, as the twisted pair of wires are pushed further onto the pointed end of the tongue, the twisted pair is allowed to rotate slightly so that the pointed end may pass between the twisted wires so as to open the twist so as to separate the wires so that each wire passes to a different side of the tongue, so as to be positioned above the terminal to which it is desired to connect the wire.

A benefit of using a connector block having a tongue with a pointed end in the entrance, is that a twisted pair of wires do not have to be pre-untwisted by hand before lacing into the connector block.

Preferably the substantially pointed end comprises a smoothly blended surface having a radius at the point less than 0.5mm.

In a further embodiment, the radius is preferably less than 0.2mm.

A benefit of the pointed end being smoothly radiused is that it does not cut or pierce an insulation covering a wire. A benefit of the radius being small is that the pointed end is then narrower than the combined width of the twisted pair and has a length shorter than that described by viewing one fat portion of the twisted pair, located between two narrow portions as viewed. Thus the pointed end and the tongue are

scaled to open one twist with minimum force, not requiring substantially more of the pair to untwist to create enough of a loop for the tongue to penetrate.

Preferably the substantially pointed end further comprises a smoothly blended surface having cylindrical surface at the point having an axial length of less than 2mm along a longitudinal axis, parallel with a longitudinal axis of a twisted pair of wires when arranged for insertion into the entrance.

In a further embodiment, the axial length of the cylindrical surface is less than 1 mm.

A benefit of a cylindrical surface is that a risk of damage to the insulation by the pointed end is further reduced, hence avoiding a risk of the insulated wire snagging on the pointed end when being inserted. A benefit of an axial length being short is that the pointed end is more easily able to enter between the wires of a tightly twisted wire pair.

Preferably the tongue further comprises a slot along its length arranged to receive a edge of a terminal.

A benefit of the terminal being located in a slot in the side of the tongue is that the terminal is enabled to resist forces normal to a slot in the terminal into which a wire is terminated. Hence the connector block is enabled to resist an axial pull out force on a twisted pair cable. A further benefit is that a relative position of the terminal with respect to the tongue is maintained during lacing.

Preferably the axial length of the cylindrical surface is greater than a width of the slot.

A benefit of the axial length of the cylindrical surface being greater than a width of the slot is that the smoothly blended surface may continue down each side of the tongue, and each side of the terminal. Hence a wire is smoothly guided into the open mouth of the respective terminal.

Preferably in use, to connect a twisted pair of wires to an insulation displacement connector block of the invention, a twisted pair of wires is positioned above the entrance so that each of the wires are orientated substantially as required for making connection with the intended terminal, the twisted pair of wires is pushed downwards so as to contact the tongue, as the twisted pair of wires are pushed further onto the pointed end of the tongue, the twisted pair is allowed to rotate slightly so that the pointed end may pass between the twisted wires so as to open the twist so as to separate the wires so that each wire passes to a different side of the tongue, so as to be positioned above the terminal to which it is desired to connect the wire.

A benefit of the twisted pair being allowed to rotate slightly within the entrance is that a maximum force of insertion is reduced as this enables a first wire to be forced through its gap ahead of a second wire of a single pair of twisted wires.

Preferably a connector has the insulation displacement connector block of the invention, and the connector is provided with a pusher means is mounted to the connector so as to be moveable to push the or each twisted pair of wires into a respective block.

A benefit of a pusher means is mounted to the connector is that no additional tool is needed to complete the termination.

Preferably the pusher means has a surface or surfaces arranged so as to push at least two pairs of twisted wires sequentially into respective blocks.

A benefit of wires being terminated sequentially is that a termination force is reduced compared to simultaneous termination of wires.

Preferably the said surface or surfaces on the pusher means are curved.

A benefit of a curved surface is that it is possible to increase the distance moved by a surface of the pusher arranged for digital operation by a user when terminating the wires. Hence the maximum operating force is further reduced as the force required for the insertion of each individual wire is better staggered or separated apart.

According to a further aspect of the present invention, there is provided an insulation displacement connector block having means for sequentially ensuring termination of the individual wires of a twisted pair cable to terminals arranged for making electrical connection to insulated wires, wherein the means comprises one or more pressure applying surfaces, and wherein the or each pressure applying surface is curved in a direction that the pressure is applied.

A benefit of the invention is that the pressure required does not exceed that which an installer may comfortably apply with his bare hands.

Preferably the curve is convex where the means presses against the wires.

A benefit of a convex curve is that the wires can slide against the pressure applying surfaces.

Preferably the means is arranged to pivot about a pivot axis. A benefit of the pivot axis is that the means may provide good mechanical advantage

Preferably the curve is in a plane at right angles to the pivot axis.

A benefit of the plane being perpendicular to the pivot axis is that there is no sideways force applied to the connector or the terminations.

Preferably, in a second embodiment of the invention, the pressure applying surface is discontinuous.

A benefit of a discontinuous pressure applying surface, is that the mechanism may be made compact.

Preferably the pressure applying surfaces are parallel to each other.

A benefit of parallel surfaces is that the same condition applies along the length of the surface.

Preferably the means when fully pressed down latches to a base.

A benefit of the latch is that it provides a positive indication to the installer that the termination has been completed satisfactorily. A further benefit is that the wires are mechanically trapped in the connector and hence can not come out of engagement.

Preferably at least one set of the terminals is arranged in a plane.

A benefit of a the terminals being in a plane is that use of the connector is simplified.

Preferably at least some of the terminals are at different heights relative to each other.

A benefit of the terminals being at different heights is that use can be made of the mechanical advantage of the pivoting mechanism to obtain a more even requirement for pressure to complete the termination.

Preferably the different heights of the terminals are arranged so that the terminals form a convex arc facing the convex curved surface.

A benefit of a convex arrangement is that towards the end of the means away from the pivot, the connector may be arranged so that each wire is terminated one at a time. A further benefit is that the terminals are spaced further apart from each other, hence when the connector is used for high frequencies there is a reduction in crosstalk.

Preferably in an alternative embodiment the terminals are all at the same height. A benefit of the terminals being all at the same height is that manufacturing may be simplified.

Preferably pairs of wire guides are provided on a or the base, the wire guides arranged to locate the wires before the means is operated to terminate the cable. More preferably the wire guides are arranged to separate the wires of a twisted pair of wires so as to guide a single wire to each terminal.

A benefit of wire guides is that satisfactory terminations may be achieved more easily.

Preferably the wire guides further comprise retention means to retain each wire within the wire guide.

A benefit of a retention means is that the wires fitted to the connector do not become dislodged as subsequent wires are fitted in their respective wire guides.

Preferably the axis is perpendicular to the plane.

A benefit of the axis and plane being perpendicular is that construction of the terminal is simplified.

Preferably when the pressure applying surface comprises at least two surfaces, one surface passes to each side of a terminal plane as the means applies pressure.

A benefit of the pressure applying surfaces passing to each side of the terminal plane is that the wires may be terminated by a applying a force in a substantially axial direction, co-incident with an axis of the individual insulation displacement terminal.

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

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

Figure 1 A is an enlarged scrap view of the perspective view of the first embodiment shown in Figure 1 ;

Figure 1 B is a second enlarged scrap view of the perspective view of the first embodiment shown in Figure 1;

Figure 2 is an end view of the electrical connector shown in Figure 1 ;

Figure 2A is an enlarged scrap view of the end view shown in Figure 2;

Figure 2B is a second enlarged scrap view of the end view shown in Figure 2;

Figure 3 is another perspective view of the electrical connector shown in Figure 1 ;

Figure 4 is a perspective view of a second embodiment of the invention;

Figure 5 is an end view of the second embodiment in the fully open state as shown in Figure 4;

Figure 5A to Figure 5D are further views of the second embodiment in sequential intermediate states until in Figure 5D the second embodiment is shown with the termination completed;

Figure 6 is a view along a longitudinal axis of a twisted pair cable of an insulation displacement connector of a third embodiment of the invention showing a pair of insulation displacement terminals and a cross-section through a twisted pair of wires from the cable positioned above an entrance to the terminals;

Figure 6A and Figure 6B are further views of the third embodiment, showing the wires at different stages of insertion into the connector;

Figure 7 is a view of an insulation displacement connector of a fourth embodiment of the invention;

Figure 8 is a view of an insulation displacement connector of a fifth embodiment of the invention; and

Figure 9 is a view of an insulation displacement connector of a sixth embodiment of the invention.

From Figure 1 , a perspective view of a first embodiment of an electrical connector 1 according to the invention is shown. The electrical connector 1 has an insulation displacement connector block 2 having means 3 for sequentially ensuring termination of the individual wires of a twisted pair cable to terminals 11 to 18 inclusive, arranged for making electrical connection to insulated wires, wherein the means comprises

three pressure applying surfaces 31 , 32 and 33, and wherein the or each pressure applying surface is curved with a radius 1C about an origin 1X (off the sheet showing Figure 2), the curve in a direction 1 P 1 Q and 1 R that the pressure is applied to terminate the wires. The means is provided with a smooth surface on a side 34 opposite to surfaces 31 , 32 and 33 so that the pressure required to operate the means does not exceed that which an installer may comfortably apply with his bare hands or digits.

In Figure 1 , it may be seen that the electrical connector is attached to a RJ45 patch panel jack, as an illustration of a possible application that is envisaged for this invention.

The surfaces 31 ,32 and 33 are curved in a convex shape so that where the means presses against the wires in the terminals 11 to 18 the wires can slide against the pressure applying surfaces so as to align themselves with the insulation displacement connectors.

The means 3 is arranged to pivot in the direction of arrows 1Q and 1 R about a pivot axis 1 A, so that a mechanical advantage may be obtained by application of pressure at an end 5 of the means.

The curved surfaces 31 , 32 and 33 lie in three parallel planes which are at right angles to the pivot axis 1 A. Hence, when the means is pivoted, there is no sideways force applied to the connector or the terminations.

The means 3 is provided with a resilient latch 6, which when the means has been fully pressed down over the terminals latches to a base 7 of the connector 1 at a detent 8. Hence, an installer can easily verify that the termination has been completed satisfactorily by testing that the means 3 has latched by pulling it in a direction away from the terminals. The latch ensures that the wires are mechanically trapped in the connector and hence can not easily come out of engagement.

In an alternative embodiment, not shown in the figures, when the means has been fully pressed down, it is arranged to latch to the base, by engaging under a lip of at least one of the resilient terminal supports, such as the lip 88 of terminal support 22.

The terminals 11 to 18 are arranged in two sets U and 1K, each set having four terminals which are arranged in a plane along the arrows U and 1K, and parallel with a vertical axis 1 V of the terminals. Since the terminals lie on a plane that is perpendicular to the axis 1 A, side faces 35 and 36 of the means may closely abut side faces 20 and 21 of terminal support 22.

From Figure 2, it can be seen that for set 1 K the terminals 11 , 12, 15, and 16 are at heights H11 , H 12, H 15, H16 respectively relative to each other. For set U the terminals 13, 14, 17, and 18 are at heights H13, H14, H17, H18 respectively relative to each other.

Preferably pairs of wire guides are provided on a or the base, the wire guides arranged to locate the wires before the means is operated to terminate the cable.

Pillar 71 is positioned between terminals 11 and 12 so as to enable the wires of a twisted pair of wires to be easily separated so as to guide a single wire to each terminal. Once a wire has been guided, for example into terminal 12, a retention means 72 retains the wire within the wire guide so that it is correctly positioned to enter the terminal 12.

From Figure 4, an electrical connector 100 of a second embodiment is shown, with a connector block 102 having means 103 for sequentially ensuring termination of the individual wires 121 to 128 of a twisted pair cable 130 to terminals 111 to 118 inclusive, arranged for making electrical connection to the insulated individual wires 121 to 128, wherein the means 103 comprises two pressure applying surfaces 131 and 132.

Means 103 pivots about an axis 100A. Compartments 141 to 148 are provided to contain ends of the wires 121 to 128 respectively so that there is no risk of adjacent wires touching. Lower end 158 of insulation displacement connector 118 is arranged for connection to a circuit board by soldering. Any excess length of the lower end 158 may be trimmed after soldering.

The terminals of the second embodiment are all in one plane lying along the axis of the arrows 10V and 10K, and perpendicular to the axis 100A. Latch 106 is provided which engages detent 108 when the means 103 has been fully operated.

An end of wire 121 is enclosed by keyhole 161 so that once placed over the insulation displacement connector 111 it is unlikely to move out of a position where operation of the means would ensure its correct termination.

Figure 5 shows the same embodiment 100 as Figure 4, in an open state, where each of the terminals 111 to 118 of connector block 102 are open to receive wires 121 to 128. Each of the insulation displacement connectors 111 to 118 are the same length, and hence it is possible to see easily from the heights of the bottoms of the insulation displacement connectors that they are all set at different levels, and that the terminals are arranged so that the terminals form a convex arc facing the convex curved surface. Initially as pressure is applied to surface 105 in the direction of arrow 10P, the means 103 moves freely in the direction of arrow 10Q. When means 103 has moved to the position shown in Figure 5A, it has started to apply pressure to wire 121 which has commenced entering the terminal 111 , and the means is about to contact wire 122 and hence a force applied to the means by pressure in the direction of arrow 10P will need to increase to cause the means to continue to move to the next state shown by Figure 5B. In Figure 5B, wire 121 has fully entered the insulation displacement connector 111 , and hence a force required to move if further down the insulation displacement connector in the direction of arrow is much reduced from the force required on entering the insulation displacement connector. At Figure 5C, the last wire 128 is about to enter the terminal 118, and it can be seen that the other wires have already entered their respective terminals and hence the pressure 10P required to complete the operation is not excessive.

When the means 103 is fully operated, the latch 106 engages with the detent in body 107, and an installer can be assured that all the wires have been satisfactorily terminated.

Hence, a benefit of the terminals being at different heights is that use can be made of the mechanical advantage of the pivoting mechanism to obtain a more even requirement for pressure to complete the termination.

In Figures 1A and 2A, scrap views of the first embodiment 1 as shown in Figures 1 and 2 respectively, are enlarged to more clearly show the terminals 15 and 16 and a portion of the base 7. Other terminals of set U are not shown in these views.

Terminal 16 is mounted between terminal support 22 and pillar 74 and terminal 15 is mounted between terminal support 24 and the pillar 74. From Figure 1A, it can be seen that the terminals 15 and 16 are supported between the terminal supports 22 and 24 and the pillar 74 in grooves 75, 76, 77 and 78.

The insulation displacement connector block 2 is arranged for termination of a twisted pair cable 99 (shown in Figure 1A as having only one twisted pair 991 of wires, but a typical cable would have a plurality of twisted pairs of wires). The connector block 2 has two adjacent insulation displacement terminals 15 and 16 arranged for making electrical connection to insulated wires 97 and 98 of a twisted pair of wires of the cable 99 (shown discontinuous in Figure 1Afor clarity, the "broken ends" shown separated by the centre lines 1 E and 1 F which run through the centres of the wires when fully inserted in the terminals). The wires 97 and 98 have conductive cores 95 and 96 respectively (note cross-sections are not cross-hatched in these drawings). The terminals 15 and 16 each have an open mouth 79 and 80 respectively, arranged to receive a single one of the wires, the open mouths facing a single entrance 81 through which both wires are arranged to be inserted each to its own terminal. The pillar 74 forms an upstanding tongue 82 between the terminals 15 and 16. The tongue 82 having a substantially pointed end 83 facing the entrance 81. The pointed end 83 extends beyond the mouths 79 and 80 of the terminals 15 and 16 to the entrance 81. The tongue is arranged to not extend beyond the entrance 81. The tongue 82 divides the entrance 81 to provide two gaps 85 and 86.

From Figure 2A it can be seen that each gap 85 and 86 is smaller than a diameter 84 of a single insulated wire 97 or 98. Each terminal support 24 and 22 has a lip 87 and 88 respectively so as to form a side of the gaps 85 and 86. From Figures 2A and 6, 6A and 6B it can be seen that the lips 87 and 88 and 287 and 288 are each arranged to each trap one of the wires when it has been partially inserted into the connector block 2 and 200, and the wire is positioned above open mouths 79 and 80 respectively and 279 and 280 respectively.

In alternative embodiment shown in Figures 9, which is closely similar to the first embodiment, other than that in the sixth embodiment the lips 687 and 688 are on the tongue 682. In a further embodiment not shown in the figures lips are provided on both the tongue and each of the opposed surfaces of the terminal supports. In a particular embodiment not shown in the figures, it may be convenient to combine features from several of the embodiments, so that for example for one terminal of a pair, the lip is provided on the terminal support and for the other terminal the lip is provided on the tongue.

To facilitate the insertion of each of the wires through the gaps 85 and 86, the terminal supports are resiliently deflectable in the direction of arrows 2P and 2Q so that the lips 87 and 88 are resiliently deflectable away from each other.

The entrance 81 is defined at its outer extent by an outwardly facing surface 89, the outwardly facing surface facing away from the mouths 79 and 80 of the terminals 15 and 16. In the first and the third embodiments, the outwardly facing surface 89 and

289 has a first outwardly facing surface 90, 290 and a second outwardly facing surface 91 , 291 , the first and second outwardly facing surfaces are on different planes 2G and 2H, 6G and 6H perpendicular to a direction of insertion 2J, 6D of a wire 97 or 98 into one of the terminals 15 or 16. A width 2W of the entrance at its outer extent 89' is equal to or larger than twice the diameter 84 of a single said insulated wire 97 or 98.

In an alternative embodiment, since there may be a slight gap between the twisted pair wires, the width 2W is equal to a effective width 2E across the twisted pair.

Each of the lips 87 and 88 have an inclined surface 92 and 93 arranged to funnel a wire into its respective gap. Hence in use, as a twisted pair is moved towards the entrance, should wire 98 strike a edge 94 as shown in Figure 2A, it will be deflected in the direction of arrow 2R, so as to then slide down inclined surface 93 until wire 97 strikes inclined surface 92, when the terminal supports will resiliently deflect allowing the lips 87 and 88 to move away from each other, hence increasing a dimension of the gaps 85 and 86 so as to permit the wires to be positioned above the open mouths 79 and 80. When the wires are trapped in this position they may then be moved into a terminated position where the conductive cores 95 and 96 make electrical contact with the terminals 15 and 16 by operation of the pusher means 3 pushing the wires into the terminals and hence causing the terminals to displace the insulation at each side of the conductive cores.

Each of the lips each further comprise an inwardly facing surface 187 and 188, the inwardly facing surface facing in a direction towards the adjacent open mouth 79 or 80, the facing direction being the same direction as the direction of insertion 2J of a wire into one of the terminals. Each of the inwardly facing surfaces 187 and 188 defining an inner extent of the respective inclined surface 87 and 88. From Figure 2A it can be seen that the inwardly facing surfaces are on different planes 2K and 2L perpendicular to the direction of insertion.

While the inclined surface is arranged to assist in the wire passing through a gap, by a downward movement of the wire resulting in a sideways force causing the lip and the support to deflect outwards, the inwardly facing surface is such that an upward force on the wire does not easily result in the outward deflection of the lip or the support, and hence a wire is more securely retained in a space above an open mouth of the respective terminal. Hence a benefit of the asymmetric profile of the lips is that less force is required to move the wire though the gap into the said space, lacing the wire into the connector block, than to remove it, that is unlacing the connector block.

In the embodiments shown in Figures 7 and 8 the inwardly facing surfaces are on the same plane perpendicular to the direction of insertion.

The tongue 82 preferably extends to or beyond one of the inwardly facing surfaces, and in the case of the embodiment of Figure 2A the tongue extends beyond both of the inwardly facing surfaces 187 and 188.

Hence the end 83 of the tongue 82 is within the entrance 81. In the first embodiment shown in Figure 2A, the tongue ends is arranged so that when the twisted pair is inserted into the entrance, the pointed end 83 strikes the twisted pair at 2T, which lies between a substantially vertical centre line 2U and 2V through a longitudinal centre axis each of the wires. Hence, as the wires are inserted in to the connector, they are consistently guided to either side of the tongue.

In the embodiment shown in Figures 8 and 9 the tongue is resiliency deflectable towards either of the lips, the tongue is resiliently deflectable to either side.

In a particular embodiment, it has been found that suitable dimensions for a tongue similar to the tongue of the first embodiment shown in Figures 1 B and 2B, are approximately a width 1 BW of the tongue is 1 mm, a length 1 BL is 2mm, and a length 1 BC of the cylindrical portion is 0.47mm and a width 1 BD across a chord of the cylindrical portion is 0.18mm. A suitable tip radius 2BR for the pointed end has been found to be approximately 0.1mm, and a suitable spacing 2BT between the insulation displacement terminals is approximately 2mm.

In a particular embodiment similar to the first embodiment, for the system to work well the width of the point of the tongue running 90 degrees to the axis of the twisted pair has to be narrower than a dimension from the axial centre line of one wire in the pair to the axial centre line of the other, (i.e. roughly one wire diameter- approx. 1mm).

Similarly a length of the point of the tongue running parallel to the axis of the twisted pair is preferentially shorter than the fat section of one twist, i.e. the length is shorter than that described by viewing one fat portion of the twisted pair, located between two narrow portions as viewed.

Thus the point is scaled to open one twist with minimum force, not requiring substantially more of the pair to untwist in order to create enough of a loop for the tongue to penetrate. It is preferable that the overall shape of the tongue is similar to the "oval slot' shape described between the pair of wires viewed normal to the fat part

of a twist. Because the point tapers on all sides leading to the main body of the tongue the loop is only opened by an amount similar to the dimensions of the main body of the tongue.

As an example of the length of one 'twist' , below are the twist rates of known Augmented Catβ, Cat6 and 5E cable pairs:-

AC6 range from 8.7 to 11.1 mm for different colour pairs Cat6 range from 10.7 to 17.1 mm Cat 5e range from 15.1 to 19.1 mm These dimensions are the linear distance a wire travels to do a complete 360 degree turn i.e. where its position repeats. One twist (see twist 1T in Figure 1A) in fact encompasses two loops looked at from the same direction (e.g. green / white then white / green).

The tongue of the present invention is arranged to open one loop, a length that occupies half this distance.

So for the system to work effectively for e.g. the smallest twist rate 8.7 mm, the point and tongue should be considerably less than half (4.35mm) this in length parallel to the pair axis. In fact to take account of the diagonal width of the pair either side of the loop, in effect to correspond to a dimension of a twist gap in the centre of a loop, the tongue should be over 2mm shorter than this. The tongue at it's maximum is preferably 2 mm by 1 mm oval, describing a circumference offering minimal disturbance lengthwise to the loop compared to the loop at rest.

From Figures 1 and 1 A the substantially pointed end can be seen to have a smoothly blended surface having cylindrical surface at the point having an axial length of less than 2mm along a longitudinal axis, parallel with a longitudinal axis of a twisted pair of wires when arranged for insertion into the entrance. The cylindrical surface is preferably at least as long as a width of a slot along the length of the tongue arranged to receive an edge of a terminal. The slot providing a location to retain the terminal in a desired orientation in the connector block.

Hence an axial length of the cylindrical surface is preferably greater than a width of the slot. In use, to terminate a twisted pair cable to an insulation displacement connector block of the invention, a twisted pair of wires is positioned above the entrance so that each of the wires are orientated substantially as required for making connection with the

intended terminal, the twisted pair of wires is pushed downwards so as to contact the tongue, as the twisted pair of wires are pushed further onto the pointed end of the tongue, the twisted pair is allowed to rotate slightly so that the pointed end may pass between the twisted wires so as to open the twist so as to separate the wires so that each wire passes to a different side of the tongue, so as to be positioned above the terminal to which it is desired to connect the wire.

A printed circuit board may be mounted underneath the connector to interconnect the connector with other circuit components.

From Figure 6 a connector block 200 of a third embodiment of the invention showing a pair of insulation displacement terminals 215 and 216 and a cross-section through a twisted pair of wires 297 and 298 from a twisted pair cable positioned in an entrance 281 to the connector. Terminal 216 is mounted between terminal support 222 and pillar 274 and terminal 215 is mounted between terminal support 224 and the pillar 274. Figure 6A shows the wires 297 and 298 at a stage of insertion into the connector 200 where the terminal supports 222 and 224 are deflected away from each other in the directions 6P and 6Q to permit the wires to pass through gaps 285 and 286 to a position as shown in Figure 6B where they are trapped by the by the supports 222 and 224 resiling back to their rest position. The wires are inserted by applying a force in a downward direction of arrow 6D, and as they move from the position shown in Figure 6 to that of Figure 6A, a pointed end 283 of the tongue 282 is forced between the wires, opening the twist only at the location of the terminals. Inclined surfaces 292 and 293, are in this embodiment smoothly continuous with upper radiuses 294 and 295 respectively which are smoothly continuous with first outwardly facing surface 290 and second outwardly facing surface 291 of the outwardly facing surface 289. The outwardly facing surface 289 defines the outer extent 289' of the entrance. Inclined surfaces 292 and 293 on supports 222 and 224 funnel the wires into the gaps between lips 287 and 288 and the tongue 282.

The inclined surfaces 292 and 293 and the lips 287 and 288 form inwardly facing opposed surfaces defining sides of the entrance 281.

A lower extent 276 of the entrance 281 is defined by a lower edge 277 and 278 of the lips 287 and 288 respectively.

From Figures 6 and 6B it can be seen that the tongue 282 extends into the entrance 281 , since tongue and the pointed end 283 are such that the tongue is shorter than or lower than or within the outer extent 289' and longer than or higher than or beyond

the inner extent 276.

The tongue 282 extends upwards from the base 207 in an upward direction 6U opposite to the direction 6D along which wires are moved to insert them into the connector block.

Figure 7 is a view of an insulation displacement connector of a fourth embodiment 400 of the invention, having terminals 415 and 416 and a portion of the base 407. Terminal 416 is mounted between terminal support 422 and pillar 474 and terminal 415 is mounted between terminal support 424 and the pillar 474.

Wires 497 and 498 are positioned above the connector 400 ready to be inserted along a direction of arrow 4D as in the first and third embodiments. Inclined surfaces 492 and 493, extend between an outer extent 489' of the entrance which is co-planar with first outwardly facing surface 490 and second outwardly facing surface 491 of the outwardly facing surface 489. Inclined surfaces 492 and 493 on supports 422 and 424 funnel the wires into the gaps between lips 487 and 488 and the tongue 482.

A lower extent 476 of the entrance 481 is defined by a lower edge 477 and 478 of the lips 487 and 488 respectively.

The tongue 482 extends into the entrance 481, since tongue and a pointed end 483 are such that the tongue is shorter than or lower than or within the outer extent 489" and longer than or higher than or beyond the inner extent 476.

The tongue 482 has tapered sides 458 and 459 tapering to the pointed end 483. To avoid a groove for receiving the terminals 415 and 416 from leaving a sharp edge on the tapered sides, the pointed end is preferably wider than a width of the groove at its narrowest point. The iip 488 and the lower edge 478 and an inwardly facing surface 456 of support 422 form opposing surfaces to the tapered side 458, forming a space 457 within which the wire 498 may be trapped when inserted through the gap 486. The space 457 is above an, open mouth 480 of the terminal 416.

Figure 8 is a view of an insulation displacement connector of a fifth embodiment 500 of the invention, having terminals 515 and 516 and a portion of the base 507. Terminal 516 is mounted between terminal support 522 and pillar 574 and terminal 515 is mounted between terminal support 524 and the pillar 574. An outer extent 589' of the entrance which is co-planar with first outwardly facing surface 590 and

second outwardly facing surface 591 of the outwardly facing surface 589. Outer extent 589' has a width 8W, greater or equal to twice a diameter of a twisted pair of wires intended to be inserted into the terminals. The fifth embodiment differs from the fourth in that tongue 582 extends to a outer extent 589' of entrance 581 , dividing the entrance 581 into two substantially identical entrances 581' and 581". The pointed end 583 does not extend beyond the outer extent 589'.

Figure 9 is a view of an insulation displacement connector of a sixth embodiment 600 of the invention, having terminals 615 and 616 and a portion of the base 607. Terminal 616 is mounted between terminal support 622 and pillar 674 and terminal 615 is mounted between terminal support 624 and the pillar 674. Supports 622 and 624 have inclined faces 693 and 692 respectively, which face inwards to funnel a wire through a gap between the support and the tongue. An outer extent 689' of the entrance which is co-planar with first outwardly facing surface 690 and second outwardly facing surface 691 of the outwardly facing surface 689. The sixth embodiment is similar to the fifth embodiment in that tongue 682 extends to a outer extent 689' of entrance 681 , dividing the entrance 681 into two substantially identical entrances 681' and 681". The pointed end 683 does not extend beyond the outer extent 689'. However, in this embodiment, lips 687 and 688 are provided on the tongue 682. In this embodiment the tongue 682 is resiliently deflectable to either side in direction of arrows 9P and 9Q, so as to allow a wire, similar to wire 498 to pass to either side of the lips. It will be understood that since the deflection of the tongue will enlarge one gap while reducing the other, one wire must be inserted into the space 657, before the other is inserted into space 656. Since the tongue is flexible a groove for receiving the terminals does not have to extend to the pointed end 683, which in this case is spherical.

The embodiments shown in Figures 6, 7, 8 and 9 of insulation displacement connector blocks all have terminals mounted at the same relative height, on a common plane (for example plane 6C) that is perpendicular to a direction of insertion 6D.

The embodiments shown in Figures 6, 7, 8 and 9 of insulation displacement connector blocks, could all be arranged as part of a connector with a pusher means mounted to the connector similar to the means 3 of the first embodiment to insert the wires into the terminals once the wires have been trapped in the connector block as described above with particularly with reference to Figures 1 A, 2A, 6, 7, 8 and 9.