Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE OF THE INVENTION
BALANCED INTERCONNECTOR
BACKGROUND
In data transmission networks, cross-connect connectors (such as BIX, 110,
210, etc.) are commonly used in telecommunication rooms to interconnect the
ends of telecommunications cables, thereby facilitating network maintenance.
For example, the prior art reveals cross connectors comprised of a series of
isolated flat straight conductors each comprised of a pair of reversed
Insulation Displacement Contact (IDC) connectors connected end to end for
interconnecting a conductor of a first cable with the conductors of a second
cable. Even though these straight connections were known to produce an
amount of crosstalk due to capacitive coupling between pairs, the produced
crosstalk was at levels below those provided for in the standards and as such
had no adverse effect on data transmitted via the cross connector.
With the introduction of Category 6 and Augmented Category 6 standards and
the lOGBase-T transmission protocol, the allowable levels for all kinds of
internal and external crosstalk, including Near End Crosstalk (NEXT), Far End
Crosstalk (FEXT) and Alien Crosstalk, have been lowered. As a result, the
prior art connectors are generally no longer able to meet the allowable levels
for cross talk.
Additionally, although long cable elements such as the twisted pairs of
conductors achieve good crosstalk characteristics through appropriate
twisting and spacing of the pairs of conductors, when viewed as a whole, the
cable is subject to additional crosstalk at every irregularity. Such
irregularities
occur primarily at connectors or interconnectors and typically lead to an
aggressive generation of crosstalk between neighbouring pairs of conductors
which in turn degrades the high frequency bandwidth and limits data
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throughput over the conductors. As the transmission frequencies continue to
increase, each additional irregularity at local level, although small, adds to
a
collective irregularity which may have a considerable impact on the
transmission performance of the cable. In particular, unravelling the ends of
the twisted pairs of conductors in order to introduce them into an IDC type
connections introduces capacitive coupling between the twisted pairs.
SUMMARY OF THE INVENTION
In order to address the above and other drawbacks there is disclosed a
balanced interconnector comprising first and second like interconnectors,
each of the interconnectors comprising an elongate centre section and a pair
of parallel IDCs opening in substantially opposite directions, the IDCs
attached substantially at an angle to and at opposite ends of the elongate
centre sections, each of the interconnectors lying in different parallel
plains.
The first and second interconnectors are arranged such that the elongate
centre sections are opposite one another and the IDCs of the first
interconnector are not opposite the IDCs of the second interconnector.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 is a right raised perspective view of a balanced interconnector in
accordance with an illustrative embodiment of the present invention;
Figure 2 is a sectional view of a balanced interconnector taken along line 2-2
in Figure 1;
Figure 3 is an exploded view of a balanced interconnector in accordance with
an illustrative embodiment of the present invention;
Figure 4 is a partially disassembled right front perspective view of a
balanced
interconnector in accordance with an alternative illustrative embodiment of
the
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present invention;
Figure 5 is right lowered perspective view of two pairs of interconnectors in
accordance with an illustrative embodiment of the present invention;
Figure 6 is a schematic diagram of the coupling effect in accordance with an
illustrative embodiment of the present invention;
Figure 7 is an exploded view of a balanced interconnector in accordance with
an alternative illustrative embodiment of the present invention;
Figure 8 is a left raised perspective view of two pairs of interconnectors in
accordance with an alternative illustrative embodiment of the present
invention;
Figure 9 is a top plan view of the two pairs of interconnectors of Figure 7;
and
Figure 10 is a raised perspective view of a plurality of balanced
interconnectors and support frame in accordance with an illustrative
embodiment of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS
Referring now to Figure 1, a balanced interconnector, generally referred to
using the reference numeral 10 will now be described. The cross connector
10 comprises an insulating housing 12 into which a first set of turrets as in
14
and a second set of turrets as in 16 are moulded.
Referring now to Figures 2 and 3 in addition to Figure 1, a series of
interconnectors as in 18 which extend from one of the first set of turrets as
in
14 to a corresponding one of the second set of turrets as in 16 are imbedded
in the housing 12. In this regard, the housing 12 is typically manufactured in
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first and second interconnecting parts 20, 22 thereby providing a simple
means for assembling the interconnectors as in 18 within the housing 12.
Each interconnector 18 is comprised of a pair of opposed elongate bifurcated
Insulation Displacement Connectors (IDC) 24, 26 interconnected by an
elongate connecting portion 28 at an angle to the fDCs as in 24, 26.
Illustratively, this angle between the IDCs 24, 26 and the elongate connecting
portion 28 is shown as being perpendicular, but angles other than
perpendicular may also be used in particular embodiments. As known in the
art, the IDCs as in 24, 26 are each comprised of a pair of opposed insulation
displacing blades as in 30. The interconnector 18 is illustratively stamped
from
a flat conducting material such as nickel plated steel, although in a
particular
embodiment the interconnector 18 could be formed in a number of ways, for
example as an etched trace on a Printed Circuit Board (PCB) or the like.
Still referring to Figures 1, 2 and 3, the first set of turrets as in 14 and
the
second set of turrets as in 16 are each arranged in two parallel rows of
turrets
defining a cable end receiving region 32 there between for receiving a cable
end 34. The insulated conductors as in 36 (typically arranged in twisted pairs
of conductors) exit the cable end 34 and are received by conductor receiving
slots 38 moulded in each of the turrets as in 14 or 16. As known in the art,
the
insulated conductors as in 36 are inserted into their respective slots as in
38
using a special "punch down" tool (not shown) which simultaneously forces
the conductor as in 36 between the bifurcated IDC, thereby interconnecting
the conductive centre 40 of the insulated conductor 30 with the IDC as in 20,
22, while cutting the end of the conductor 36 (typically flush with the outer
edge of the turret in question).
Referring to Figure 4, note that although the first set of turrets 14 and the
second set of turrets as in 16 in the above illustrative embodiment are each
shown as being arranged in two (2) parallel rows of turrets, in a particular
embodiment the first set of turrets 14 and the second set of turrets as in 16
could be arranged in a single row, alternatively also together with others, to
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form the inline cross connector as illustrated in Figure 4. Additionally,
systems
other than IDCs could be used for interconnecting the insulated conductors as
in 36 with their respective interconnectors as in 18.
Referring now to Figures 1 and 3, in a particular embodiment a wire lead
guide as in 42, comprised of a plurality of conductor guiding channels as in
44
moulded therein and adapted to fit snugly into the cable end receiving regions
as in 32, can be interposed between the cable end 34 and the conductor
receiving slots 38 moulded in each of the turrets as in 14 or 16.
Referring now to Figure 4 in addition to Figure 1, as discussed above the
first
set of turrets as in 14 and the second set of turrets as in 16 are each
arranged
in two parallel rows of turrets. As a result, four (4) interconnectors as in
18 are
illustratively arranged on either side of the cable end receiving region 32
and
divided into two (2) pairs of interconnectors 184, 188 and 185, 187 each
terminating a respective conductor as in 36 (illustratively the
interconnectors
are indicated as terminating conductors 4, 8, 5 and 7 of the twisted pairs of
conductors). The first pair of interconnectors 184, 188 lies in a first plain
and
the second pair of interconnectors 185, 187 lies in a second plain parallel to
the first plain. Additionally, the direction of the elongate connecting
portions
244, 248 of the interconnectors of the first pair of interconnectors 184, 188
is
opposite to that of the elongate connecting portion 245, 247 of the second
pair
of interconnectors 185, 187.
Still Referring to Figure 4, although the interconnectors as in 18 are not
electrically interconnected with one another, unravelling the ends of the
conductors as in 32 in order to insert them into their IDC connectors as in
20,
22 gives rise to a parasitic coupling (illustrated by capacitive elements CP1
and CP2) between the conductors, with the effect being the greatest for those
which are closest (illustratively conductors marked 4-7 and conductors
marked 5-8). As known in the art, especially at high frequencies such coupling
can have a large detrimental effect on a transmitted signal. In particular, in
the
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illustrated case differential signals travelling on the pair of conductors
marked
7-8 give rise to differential signals on the pair of conductors marked 4-5 and
vice versa. This effect is counteracted by the positioning of the
interconnectors in the manner shown which gives rise to an inherent coupling
(illustrated by the capacitive elements Cil and C12) between interconnectors
as
in 18 lying in the same plain. The inherent capacitances C,, and C12
effectively
cancel the differential mode signals that would otherwise be induced in the
pair of conductors marked 4-5 by the pair of conductors marked 7-8 and vice
versa.
This effect is illustrated in the capacitive network as shown in Figure 5,
where
both components of the differential signal on the conductors marked 7-8 is
coupled into each of the conductors marked 4-5, thereby effectively cancelling
out the differential signal. In this manner, the inherent capacitors cancel
crosstalk introduced into the conductors (not shown) terminated by the
interconnectors by the necessary unravelling of the twisted pairs of
conductors in order to insert their ends into the bifurcated interconnectors.
Referring now to Figure 6, in an alternative illustrative embodiment of the
present invention, the cross connector 10 is comprised of a housing 12
manufactured in first and second interconnecting parts 20, 22. The first
interconnecting part 20 further comprises a series of turrets as in 46
illustratively arranged at the corners of the outer surface 48 of the first
interconnecting part 20. Similarly, the second interconnecting part 22 also
comprises a series of turrets as in 50 illustratively arranged at the corners
of
the outer surface 52 of the second interconnecting part 22. The substantially
flat interconnectors as in 18 are arranged in pairs such that adjacent
interconnectors as in 18 have their flat sides at right angles to one another.
In
other aspects, the alternative illustrative embodiment is similar to the first
illustrative embodiment as described in detail hereinabove.
Referring now to Figure 7, as discussed above, the unravelling the twisted
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pairs such that they may be inserted between the blades as in 30 of the
bifurcated Insulation Displacement Connectors (IDC) 24, 26 gives rise to a
parasitic coupling between the conductors as in 36 which will introduce cross
talk, illustrated by capacitive elements CP4_7, Cpa_$, Cp5_7 and Cp5_$ (again,
illustratively the interconnectors as in 18 are indicated as terminating
conductors 4, 8, 5 and 7 of the twisted pairs of conductors).
Referring now to Figure 8, an inherent capacitive coupling, illustrated by
capacitive elements C14_7, C14_8, C15_7 and C15_8, is set up between the
interconnectors as in 32. Provided distance Dc between the centres of
adjacent interconnectors as in 18 is much greater than the distance DS
separating interconnectors terminating a particular pair of conductors
(illustratively the distance D is about 10 times greater), these inherent
capacitances are substantially equal and as a result form a capacitive network
which combats crosstalk which would otherwise effect signals transmitted on
the conductors due to the parasitic coupling.
Referring now to Figure 9, the cross connector 10 is illustratively modular
and
adapted for mounting, typically along with one or more like cross connectors
as in 10, in a receptacle machined or otherwise formed in supporting frame
54, such as a patch bay panel or the like. In this regard, once the cross
connectors as in 10 are mounted on the supporting frame, one set of turrets is
exposed on each side of the supporting frame 54.
Although the present invention has been described hereinabove by way of an
illustrative embodiment thereof, this embodiment can be modified at will
without departing from the spirit and nature of the subject invention.
