[0001] The present invention relates to an electrical connector for use in telecommunications.
[0002] Telecommunications utilities provide a network of cables through which the calls
they handle can be routed. These cables can be of optical fibre or conductive copper,
but the end of the network close to the subscriber is usually copper. As the network
is usually of necessity laid prior to application for service by subscribers, it is
necessary to provide a flexible network which can be reconfigured as required by the
pattern of subscribers, and to allow for disconnection, reconnection, and connection
of new subscribers.
[0003] Accordingly, the usual practice of a utility when laying a new local network is to
install a multi-pair cable, such as a 400 pair cable, from the exchange past a number
of distribution points. Each individual pair is accessible at several distribution
points, so the resulting network is highly flexible. This practice is acceptable for
voice telephony and low speed data use.
[0004] A distribution point is typically housed in a cabinet at the roadside, although other
arrangements are used, and contains an array of connectors at which wire pairs leading
to the consumer premises can be attached to form a spur. Each spur is tapped into
a pair of the cable, enabling service to be provided. If that service is discontinued,
the relevant spur is removed and the connector becomes available for use in providing
service to another consumer.
[0005] However, when a connection is made at a distribution point other than the last, the
additional cable between the chosen distribution point and the last acts as a further
spur of cable off the electrical path between the exchange and the subscriber. In
high speed data uses such as ISDN and DSL/ADSL, this further spur is one of the factors
placing an upper limit on the available speed. It is therefore necessary on occasions
to "clean the copper", ie locate the spurs of unused copper and cut them off. This
is a lengthy process, estimated at costing $800 per pair, and also reduces the flexibility
of the network to meet future demand. If the service to that subscriber is discontinued
then that pair can only be reused if another consumer adjacent the same distribution
point happens to request service. Even then, it is unlikely that sufficiently accurate
records could be kept to enable that pair to be re-used.
[0006] The present invention therefore provides a telecommunications connector for a distribution
point comprising a base part and a detachable configuration module, the configuration
module being able to be fitted in a plurality of dispositions with respect to the
base part, the base part having connection means to (i) a telecommunications cable
from an exchange, (ii) a cable to a further distribution point, and (iii) a cable
to a consumer, wherein the configuration module causes electrical connection from
the exchange to the further distribution point in a first disposition but not in a
second disposition.
[0007] This permits the installer who is connecting a new consumer to disconnect the unnecessary
part of the wire forming the relevant pair when activating the service. If service
should be discontinued, the pair can be reconstructed. This leaves intact the investment
in the network. Such an operation can also be carried out by an installer without
assistance from the specialist cable engineer required for cleaning the copper. By
integrating the switching into the connector unit a reliable and reusable network
is achieved which can be manipulated by non-specialist staff.
[0008] As the configuration module is detachable, it can be removed and replaced in a different
orientation. Such a change in orientation has advantages in use, in that can be made
more apparent on visual inspection.
[0009] The configuration module can also contain protective devices for the line, such as
three or five pin protection, over current devices and over voltage devices, or other
active electronic elements such as (but not limited to) line termination devices,
remote identification devices, and so on.
[0010] It is further preferred that in the first orientation, the configuration module causes
electrical connection between the exchange and consumer to be broken. Thus, the exchange
is always connected to either a consumer or a further distribution point (except at
the last), but potentially never both.
[0011] Removable configuration modules according to the present invention may thus have
seven electrical connections, being two each for the pairs leading to the exchange,
further distribution point and consumer, together with an earth. However, designs
with less than 7 pins or more than seven pins are possible.
[0012] In a further aspect, the present invention provides a telecommunications connector
for a distribution point, comprising a base part and a detachable configuration module,
the configuration module being able to be fitted in a plurality of dispositions with
respect to the base part, the base part having connection means to (i) a telecommunications
cable from an exchange, (ii) a cable to a further distribution point, and (iii) a
cable to a consumer, the configuration module being in the form of a five pin protector
module for a telecommunications line, one pin being for earth, and the remaining four
pins including two pairs, one pair being for an incoming telecommunications line and
the other being for an outgoing telecommunications line, the base unit having a seven
pin socket in which the five pin module is adapted to seat in the plurality of dispositions
thereby to cause electrical connection from the exchange to the further distribution
point in a first disposition but not in a second disposition.
[0013] Embodiments of the present invention will now be described with reference to and/or
as illustrated in the accompanying figures, in which;
Figure 1 is a schematic illustration of a local telephone network;
Figure 2 is a schematic illustration of the electrical structure at a distribution
point according to the prior art;
Figure 3 is a schematic illustration of the electrical structure at a distribution
point according to the present invention, in a first orientation;
Figure 4 is a schematic illustration of the electrical structure at a distribution
point according to the present invention, in a second orientation;
Figure 5 is a perspective view from above of a base unit according to a first embodiment
of the present invention;
Figure 6 is a perspective view from below of a configuration module according to the
first embodiment;
Figure 7 is a cut away view showing the electrical contacts and surge arrestor only
of the base unit and the configuration module of figures 5 and 6;
Figure 8 is a perspective view from above of the base unit of the first embodiment
showing the electrical conductors of the configuration module in place;
Figure 9 is a perspective view from above of the configuration unit of the first embodiment;
Figure 10 is a sectional view of a second embodiment of the present invention, in
a first disposition;
Figure 11 is a sectional view according to figure 10 but showing a second disposition;
Figure 12 is a schematic view of the electrical connections to the base unit according
to a third embodiment;
Figures 13 and 14 are top and sectional views of the electrical conductors of an unprotected
configuration unit according to the third embodiment, respectively, figure 14 being
a section on XIV of figure 13;
Figures 15 and 16 are top views of the mating parts only of the electrical conductors
of both the base and configuration units of the third embodiment, when connected in
a first and second disposition respectively;
Figures 17 and 18 are top and side views of the electrical conductors of an protected
configuration unit according to the third embodiment, respectively, figure 18 being
a section on XVIII-XVIII of figure 17;
Figure 19 is a perspective view of the third embodiment, showing the base unit and
the conductors only of the configuration unit;
Figure 20 is a perspective view of the third embodiment, showing the base unit partially
cut away and the conductors only of the configuration unit;
Figure 21 is a perspective view of the third embodiment, cut away to show the conductors
only of the base and configuration unit together with the connection means;
Figures 22 and 23 are views of the third embodiment from beneath, showing alternative
connection routes;
Figure 24 is a perspective exploded view of a fourth embodiment;
Figure 25 is a perspective view of the conductive components of fig 24;
Figure 26 is a perspective view of the operative parts of figure 24, in a first state;
and
Figure 27 is a perspective view of the operative parts of figure 24, in a second state.
[0014] Referring to figure 1, a typical local network includes a 400-pair cable 100 which
enters the area to be served and splits into branch cables such as 102 which contain
a lesser number of pairs. Each branch cable is connected to a number of distribution
points such as those at 104 and 106. The cable branches repeatedly at branch points
such as 108 so as to serve a large number of such distribution points. An individual
pair, such as (for example) pair number 81 of the 400 may itself branch at a number
of such branching points 108 and be made available at a number of distribution points
on that branch and on other branches. Figure 1 shows the pair numbers which (in this
example) are made available on each branch or segment of the line. The distribution
points at which pair no. 81 is available are indicated with a *. It will be seen that
this pair is available at six distribution points and branches twice along its length.
[0015] This branching does not present a problem in voice telephony and low rate data use.
The demands placed on the electrical properties of the pair are sufficiently light
to cope with such branching. However, high speed data use such as ISDN and DSL/ADSL
demand a better response and the signal echo generated by branches such as are shown
in figure 1 produces an unacceptable impairment of the electrical properties. Therefore,
assuming that the subscriber was connected to the network via pair 81 at distribution
point 106 it will be necessary to locate distribution point 110 where pair 81 is also
available, identify the appropriate wire pair and cut it. There will be a short branch
between branching point 108 and distribution point 110, but this is not so long to
detrimentally affect the electrical properties of the pair. However, this process
is lengthy and expensive since specialist cable connection staff must be called upon,
and involves a permanent degradation of the network capabilities.
[0016] Figure 2 shows the typical electrical structure at a distribution point. A wire pair
112 enters the distribution point and continues on through and out as 114. Electrical
connections 116 are made with each wire of the pair and brought to a connector 118
which is usually of the insulation displacement type (IDC). At the IDC connector 118,
a pair 120 is connected and leads away from the distribution point to the subscriber.
[0017] Where no subscriber is connected at that distribution point, the pair therefore continues
undisturbed. Where a subscriber is connected, this is essentially by way of a tap
on to the existing wire pair.
[0018] Figures 3 and 4 illustrate the principle behind the present invention. A wire pair
112' enters the distribution point and departs as wire pair 114'. However, the two
wire pairs are not connected together directly but instead each end at connectors
122, 124 respectively. A consumer pair 120' also leaves the distribution point for
the subscriber's premises but is connected to a third connector 126. A configuration
module is connectable to any or all of the three connectors 122, 124, 126 and contains
a pair of bridging links which are able to bridge appropriate pairs. In this position
illustrated at figure 3, the bridging links 128 bridge connections 122 and 124 and
therefore link the incoming wire pair 122' with the outgoing wire pair 114'. The subscriber
pair 120' is left unconnected.
[0019] In the second disposition shown in figure 4, the conductors 128 of the configuration
unit bridge connectors 122 and 126 thereby connecting the subscriber pair 120' to
the incoming wire pair 112'. It is to be assumed that the incoming wire pair 112'
is from the exchange and the outgoing wire pair 114' is to a further distribution
point. Thus, in this disposition, the subscriber is connected to the exchange but
the "tail" of unused wire pair is left isolated, not forming part of the circuit to
the subscriber.
[0020] In the configuration shown in figure 1, it would then be a simple matter to visit
distribution point 110 and change the disposition of the configuration unit in a like
fashion. This could be done by unskilled staff since it does not require interference
with the cabling network. Equally, the process is easily reversible should service
need to be ceased to that subscriber, allowing the wire pair to be redeployed for
a different subscriber at a different distribution point. This would completely clean
the copper in a simple and reversible fashion.
[0021] Figures 5 to 9 show a first working example of how this might be put in practice.
The embodiment consists of two main parts, a base unit 200 shown in figure 5 and a
configuration unit 202 shown in figures 6 and 9. The base unit 200 contains seven
conductors 204 which are accessible on the underside of the base unit 200 via IDC
connectors. These are presented within a recess 206 on the upper surface of the base
unit 200 as upstanding metal blades such as 208. Of the seven blades, six are parallel
and arranged in pairs, one pair at one end of the recess 206, one pair at the opposite
end of the recess 206 and the third pair at the centre of the recess. The seventh
blade 210 is presented at right angles at the centre of the recess 206 between a pair.
[0022] In use, the central pair 212 is connected to the wire pair 112' from the exchange.
The pair of connectors 214 at one end of the recess are connected to the ongoing pair
114' leaving two further distribution points. The pair of blades 216 at the other
end of the recess 206 are connected to the subscriber pair 120'.
[0023] The configuration unit 202 contains two conductors 218 , 220. These are spaced and
arranged so that they will bridge the gap between either blades 212 and 214 or blades
212 and 216. The mating surfaces between the base unit 200 and the configuration unit
202 are made symmetric under a rotation of 180° and therefore the configuration unit
202 can be placed in any one of two dispositions so as to effect connection between
the appropriate set of blade pairs.
[0024] Thus, when placed in the first orientation the configuration unit causes the incoming
wire pair or 112' from the exchange to be connected to the outgoing wire pair 114'
to further distribution points. When inserted in a rotated disposition, the configuration
unit 202 causes the incoming wire pair 112' to be connected to the subscriber 120
and disconnected from the outgoing wire pair 114'. Thus, the principle illustrated
in figures 3 and 4 is effected.
[0025] Figure 8 shows the base unit 200 with the conductors 218, 220 of the configuration
unit 202 in place and the remainder of the configuration unit 202 cut away. It will
be seen that the conductors make electrical contact on one side of the blades 208.
[0026] Figure 7 shows the two units connected but with all non-conducting parts removed.
It can be seen that a three pole protection module 222 such as a gas discharge tube
is connected at either end to the conductors 218, 220 and at its centre to a further
conductor 224 which grips the sides of the earth contact 210. Thus, the configuration
unit 202 is also able to offer protection to the line if desired. It will be seen
that if protection is undesired for a particular line, the protection unit 222 can
simply be omitted.
[0027] Figure 9 shows the configuration unit 202 from above. A pair of recesses 226, 228
are formed into which extend the ends of the conductors 218, 220. The recesses 226,
228 would normally be filled with a gel, grease, or other conformable material to
allow environmental protection. Nevertheless, such material can be penetrated by crocodile
clips or test leads of various types thereby allowing test access to the port. Thus,
for maintenance purposes an engineer will be able to make temporary contact to the
line to ascertain whether or not a call is in progress. If not , he can remove the
configuration unit 202 and gain access to the three wire pairs therewithin. If testing
of a central pair 212 reveals no connection to the exchange, the engineer can ascertain
whether the pair has been disconnected at a distribution points closer to the exchange.
The engineer can also test the quality of the line from blade 216 to the subscriber,
thereby achieving "look both ways testing".
[0028] A further embodiment of the invention will now be described with reference to figures
10 and 11. A base unit 300 contains a pair of conductors 302, 304. The first conductor
302 consists of a first lower IDC contact 306 which projects from the lower face of
the base unit 300 and a first upper split beam contact 308 which projects upwardly
of the base unit 300. The second conductor 304 consists of a second lower IDC contact
310 which also projects from the lower face of the base unit 300, a second upper split
beam contact 312 which also projects upwardly of the base unit 300 adjacent to the
first upper split beam contact, and a subscriber IDC contact 314 which projects upwardly
of the base unit 300 at a location displaced from the second upper IDC contact 312.
The first and second upper split beam contacts 308,312 project upwardly of the base
unit 300 by different lengths, the second (312) being shorter.
[0029] A mating face 316 is formed on the upper surface of the base unit 300 around the
first and second upper split beam contacts, enclosing them within a recess 318 so
as to permit environmental protection by way of gel, grease or the like, and also
supporting them so as to prevent unintended deformation during use. A configuration
module 320 is formed with a complementary mating face 322 to allow it to be joined
to the base unit 300. The mating faces 316, 322 are symmetrical under a 180° rotation
and therefore the configuration unit can be attached in at least two dispositions.
[0030] The configuration module 320 contains a conductor 324 which has two legs 326, 328
extending towards the space enclosed by the mating face 322 of the configuration module
320. The leg 328 is longer than the leg 326 by a length corresponding to the difference
in length of the first and second upper split beam contacts 308, 312.
[0031] The subscriber IDC contact 314 may be supported appropriately in a suitable structure
and provided with wire carrying structures to permit a wire to be inserted and removed
as necessary. The precise structure of this is not germane to the present invention
and will not be described in detail. Suitable structures are illustrated and described
in our earlier patent publications GB 2129630 and EP0683925.
[0032] This arrangement is duplicated alongside the above-described arrangement so as to
allow for wire pairs to be connected. For ease of explanation, the connection of one
wire of the pair will be described. The other wire of the pair connects in like fashion
to the duplicate.
[0033] In use, the base unit 300 is installed at a distribution point and a wire pair 330
from an exchange is attached to the second lower IDC contacts 310. A wire pair 332
leading to a further distribution point is attached to the first lower IDC contacts
306. The configuration unit 320 is attached via the mutual mating faces in a first
disposition such that the longer leg 328 mates with the (shorter) second upper split
beam contact 312 and the shorter leg 326 mates with the (longer) first upper split
beam contact 308. Thus, the wire pair 330 is connected to the wire pair 332 and the
pair is in effect allowed to continue through the distribution point to a more distant
distribution point.
[0034] When a subscriber is to be connected, a test probe can be attached to the subscriber
IDC contact to ensure that a call is not then in progress. Assuming not, the configuration
module is then removed, breaking the pair at that distribution point. A wire pair
334 leading to the subscriber's premises is then attached to the subscriber IDC contacts
314 and the configuration unit 320 replaced in a disposition which differs by a 180°
rotation.
[0035] In this rotated disposition, the longer leg 328 is above the first upper spilt beam
contact 308 and makes contact therewith. The first upper split beam contact 308 is
designed so as to be able to accept the length of the leg 328. However, the shorter
leg is insufficiently long to meet the second upper split beam contact 312 and accordingly
there is no electrical continuity between the conductors 302, 304. The pair therefore
remains broken at this distribution point, but in a reversible fashion since connection
can be remade by replacing the configuration unit 320 in its original disposition.
The subscriber is nevertheless connected to the exchange since the second lower IDC
contacts 310 and the subscriber IDC contacts 314 are parts of the same electrical
conductors 304.
[0036] A yet further embodiment of the present invention will be described with reference
to figures 12 to 23. Figures 12 to 18 show the contacts and conductors only for clarity,
figures 19 to 21 show a physical arrangement corresponding to figures 12 to 18,and
figures 22 and 23 show the necessary connections on the rear face of the arrangement
shown in figures 19 to 21.
[0037] Thus, in figure 12 there is shown a plan view of a 7-pin connection point 400. A
central pin 402 is connected to earth 404. A subscriber pair of connectors 406, 408
located to one side of the central earth connector 402 are connected to a wire pair
410 leading to a subscriber's premises. On the other side of the earth connector 402
are two pairs of connectors, a first pair 412, 414 which are connected to a wire pair
416 leading to a subsequent distribution point and a second pair 418, 420 arranged
either side of the first pair 412, 414 and which are connected to a wire pair 422
leading to the exchange.
[0038] A configuration module contains a pair of conductors 424,426 arranged and formed
as shown in figures 13 and 14. Each is generally U-shaped with a connection point
at either free end 428, 430 of the U. One free end 428 is half the width of the other
430, achieved by a step 432 along the U-profile, on one side. The other conductor
424 has a like step in a mirror image configuration. The free ends of the conductors
424,426 are able to mate with the connectors 406,408, 412, 414, 418 and 420 by suitable
IDC formations on the latter (not shown).
[0039] Figures 15 and 16 show how these conductive elements can be connected. Figure 15
shows a first disposition. The conductors 424, 426 of the configuration unit engage
with those connectors of the base unit 400 which are in an appropriate location to
meet. Thus, the wider free ends 430 bridge the first and second pairs of connectors
412, 418 and 414, 420 respectively whilst the narrower free ends 428 miss the subscriber
pair 406, 408 since the asymmetric step 432 results in the narrower free end 428 being
offset.
[0040] In the second disposition shown in figure 16, the configuration module is rotated
through 180°. This places the narrower free ends 428 in the vicinity of the first
and second pairs of connectors 412, 418 and 414, 420 and the wider free ends 430 in
the vicinity of the subscriber pair of connectors 406, 408. Thus, connection is made
with the subscriber pair, but the narrower free end 428 only makes connection with
the second pair 418, 420 leading to the exchange. Thus, the subscriber is connected
to the exchange but the spare tail of wire pair leading to the further distribution
point is disconnected giving a clean copper connection to the exchange.
[0041] Figures 17 and 18 show the arrangement of conductors in a protected configuration
module. A three pole protector 432 is located above the U-conductors 424, 426 such
that its end caps 434, 436 contact the conductors. A further conductor 438 is arranged
beneath the protector 432 in contact with its central earth contact 440, and descends
downwardly to make contact with the earth connector 402 of the base unit 400, when
in place.
[0042] Figures 19 to 22 show an example using the conductor arrangement principle shown
in figures 12 to 18. To demonstrate alternative ways of employing this principle,
a physically different layout is illustrated in which the principle and mode of operation
is however identical. To aid understanding, like reference numerals but incremented
by 100 are employed to denote corresponding parts. Thus, figures 19 to 21 show the
base unit 500 including a recess 540 in which are located the subscriber pair 506,
508, first pair 512, 514 and second pair 518, 520 of contacts. The configuration module
(not shown) is able to fit into the recess and contains the U-conductors 524, 526
(shown).
[0043] The subscriber pair of contacts 506, 508 lead to a pair of IDC contacts 542, 544
to which a wire pair leading to the subscriber's premises may be attached. The IDC
contacts 542, 544 may be supported appropriately in a suitable structure and provided
with wire carrying structures to permit a wire to be inserted and removed as necessary.
The precise structure of this is not germane to the present invention and will not
be described in detail. Suitable structures are illustrated and described in our earlier
patent publications GB 2129630 and EP0683925.
[0044] The first pair of IDC contacts 512, 514 lead to IDC contacts 546, 548 which project
from beneath the base unit 500. As shown in figure 23 they are connected to the IDC
blades 550, 552 of a first MINI ROCKER® connector 554 via wires 556, 558, for receiving
the wire pair leading to the further distribution point. MINI ROCKER® connectors are
single pair push-fit connectors for making connection to wire pairs as required. They
are also shown, in a different context, in our earlier application published as GB
2293699.
[0045] The second pair of IDC contacts 518, 520 also lead to IDC contacts 560, 562 which
project from beneath the base unit 500. As shown in figure 23 these are connected
to the IDC blades 564, 566 of a second MINI ROCKER® connector 568 for receiving the
wire pair from the exchange.
[0046] Thus, the base unit 500 is fitted in a distribution point and wire pairs to the exchange
and a further distribution point fitted to the MINI ROCKER® connectors. The configuration
unit is then inserted in a first disposition, connecting the first and second IDC
connectors 512, 514 and 518,520, and linking the exchange pair to the further distribution
point pair.
[0047] As and when a subscriber is to be connected, the configuration unit is removed and
a subscriber pair connected to the blades 542, 544. The configuration unit is then
replaced in a reversed disposition, thereby connecting the second IDC connectors 518,
520 to the subscriber IDC connectors 506, 508, linking the subscriber pair to the
exchange pair and disconnecting the further distribution point pair.
[0048] If the subscriber needs to be disconnected, the configuration unit is removed, the
subscriber pair removed, and the configuration unit replaced in its original orientation.
The original network architecture is then restored with no loss of flexibility.
[0049] Figure 23 shows an alternative wiring for the base unit 500. Instead of connecting
the first IDC contacts 560, 562 to the first MINI ROCKER® and the second IDC contacts
546,548 to the second MINI ROCKER® , the A legs 546, 560 of the first and second IDC
contacts are connected to the first MINI ROCKER® and the B legs 548, 562 of the first
and second IDC contacts are connected to the second MINI ROCKER® . Thus, to install
the device the engineer fits the two A legs from the exchange and further distribution
point pairs to the first MINI ROCKER® and the B legs to the second MINI ROCKER® .
In some circumstances that may be more convenient. The subsequent operation of the
device is identical.
[0050] Finally, the fourth embodiment will be described with reference to figures 24 to
27. This comprises a 5-pair base unit 600 which is modular in form allowing one or
more further 5-pair base units 602 etc to be attached at an end, thereby forming a
10,15, 20 etc pair module as desired. An end cap 604 is provided to close the attachment
points at the end of the base unit 600. A lid 605 is provided to seal the base unit
against the environment when it has been installed. A base with a different number
of pairs could alternatively be provided, but five is a convenient number.
[0051] Within each base unit 600, five substantially identical points are provided. Each
point includes a formation 606 for receiving a consumer plug 608, adjacent a pair
of sockets 610, 612 for the link pair and the exchange pair respectively. The sockets
610, 612 each contain a pair of connectors which are terminated via IDC blades at
the rear on assembly or during installation with separate wire pairs. The pair to
the exchange socket 612 leads back to the central exchange, possibly via other distribution
points, and the pair to the link socket 610 leads onward to a further distribution
point. If the unit 600 is installed at the last distribution point then the link socket
610 can be left unconnected.
[0052] A bridging link 614 fits into the sockets 610, 612 at the initial installation. This
contains a pair of conductors which make contact with conductors in the link and exchange
sockets via IDC connectors and thereby connect the exchange wire pair to the link
wire pair as per figure 3.
[0053] When a consumer is to be supplied with service, the consumer plug 608 is inserted.
It is held in place by retention formations (not shown in fig 24). Until now the relevant
formation 606 for accepting this has been left empty, allowing the service provider
to minimise investment in the plant. The consumer plug 608 comprises a consumer socket
616 akin to the link and exchange sockets 610, 612 and a MINI ROCKER® type connector
618 as described above. Conductors within the consumer plug 608 make the necessary
links between conductors in the consumer socket and 616 and the MINI ROCKER® . A wire
pair leading to the consumer premises is then connected to the MINI ROCKER® . Finally,
the bridging link 614 is removed from the link and exchange sockets 610, 612 and re-inserted
in a 180° rotated orientation into the exchange socket 612 and the newly provided
consumer socket 616. Connection is therefore broken with subsequent distribution points
and made with the consumer, as per figure 4. To close the link socket 610 and seal
it against the environment, a cap 620 is provided.
[0054] Earth connections within the base unit 600 are provided by an earth bar 622 which
runs the length of the combined units 600,602 etc. Within each 5-pair unit 600, an
earth strip 624 is provided which connects to the earth bar via an IDC connect 626
and provides the necessary earth conductors 628 appropriately positioned for access
in the link and exchange sockets 610, 612. This permits protection to be integrated
into the bridging link 614 if desired. Also, other active devices could be incorporated
into the bridging link 614 as envisaged in our earlier publication EP 0683925. Such
active devices include line termination devices, remote identification devices, subscriber
management devices, or any desired device.
[0055] Figure 25 shows the electrical conductors within the unit. As shown, the consumer
plug 608 is present and the bridging link 614 is seated in the link and exchange sockets
610, 612. Either side of the earth bar 622 and earth strip 624 are two adjacent conductors
630, 632 for the exchange pair which have IDC blades 634, 636 at their lower extremities
for connection to the wire pair and flat blades 638, 640 at their upper extremities
for connection with the bridging link 614. A similar pair of conductors 642, 644 are
provided for the link socket 610 for connection with a wire pair leading to any further
distribution point.
[0056] Within the bridging link 614 are a pair of conductors 646,648. Each extends from
over the link socket 610 to over the exchange socket 612 and includes a pair of downwardly
extending IDC blades 650, 652 projecting into the respective sockets and contacting
with the conductors therein. Thus, with the bridging link in this position contact
is made with between the exchange and link pairs.
[0057] Within the consumer plug 608, a pair of contacts 654, 656 extend from the consumer
socket 616 to a point beneath the MINI ROCKER® . A pair of double-ended IDC blades
658, 660 lie within the MINI ROCKER® and connect at their lower end with the contacts
654, 656. Their upper IDC contact is then available for connection to a wire pair
leading to a consumer.
[0058] When the bridging link 614 is moved to the exchange socket 612 and the consumer socket
616, the contacts 656, 648 therein will instead connect the exchange contacts 634,
636 and the consumer contacts 654, 656.
[0059] Fig 26 shows the unit with the bridging link 614 in the link and exchange sockets
610, 612, partially cut away. This will therefore correspond to figure 3, the system
as originally installed. The consumer plug 608 has not yet been fitted. A latch 660
on the base unit 600 engages with a tang 662 on the bridging link 614 to retain it
in place.
[0060] Fig 27 shows the unit with the consumer plug 608 present and the bridging link 614
in the exchange and consumer sockets 612, 616. It is retained by a further latch 664
which engages with the tang 662. The cap 620 is fitted in the link socket 610 and
is retained by its own tang 668 which engages with the first latch 662. The retention
formations 670 for retaining the consumer plug 608 are visible.
[0061] The multiple IDC blades of the bridging link 614 could be made multiple-use, ie able
to withstand repeated insertions. Alternatively, the bridging link could be an inexpensive
disposable item intended to be replaced at each reconfiguration of the line. The part
will also be lightweight, enabling engineers to carry a stock of such items to replace
each time one has to be removed.
[0062] In all embodiments, it would be convenient to mark the visible surface of the configuration
unit with a suitable indicia such as an arrow, to indicate to an engineer the configuration
of the device. Surrounding parts can then be marked with appropriate indicia such
as "SUBSCRIBER" so that an arrow pointing at SUBSCRIBER indicates that the device
is disposed so as to break the wire pair and connect to a subscriber pair connected
to that distribution point or elsewhere (as in point 110 of figure 1). In the fourth
embodiment, the bridging link 614 includes an arrow device 672 (fig 27) which denotes
the appropriate link. An asymmetric keying arrangement prevents the bridging link
614 from being inserted into the link socket 610 or the consumer socket 616 if it
is incorrectly aligned.
[0063] It will be appreciated that many variations can be made to the above-described embodiments
without departing from the scope of the present invention.