Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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THE IMPROVEMI~NT OF T~RMINATION STRUCTURE FOR MODULAR
TELEPHONE PLUGS
The present invention is related to telephone plugs and more particularly to term:n~tion
structure of a telephone plug.
Presently known telephone plugs usually comprise an insulation housing with contacts,
wherein an electrical cable is accommodated including an outer jacket and a number of individual
conductors t~rrnin~ted by those contacts. However, to properly tennin~te each of said individual
conductors, it is necessary to untwist those twisted pair cables; this untwisting effect is highly
undesirable in view of Near End Cross talk (NEXT).
NEXT loss is a measure of signal coupling from one circuit to another within a connector,
and is derived from swept frequency voltage mea~ ls on short lengths of 100Q twisted-pair
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test leads terminated to the connector under test. A balanced input signal is applied to a disturbing
pair ofthe connectors while the induced signal on the disturbed pair is measured at the near-end
ofthe test leads. To determine NEXT loss requirements at a given frequency, the value for
NEXT is 34 dB for a category 3 connector, 46 dB for a category 4 connector and 56 dB for
category 5 connector. For category 4 and 5 connectors the ~ return loss shall be 23 dB or
greater for frequencies between 1 and 20 MHz. For frequencies from 20 to 100 M[Hz, category 5
connectors shall exhibit a l..; .i.----.ll return loss of 14 dB or greater. These return loss values are
chosen to limit peak reflected voltage of 7% or less up to 20 M[Hz, and 20% or less from 20 to
100 MHz.
According to the new requirements of Teleco"""~"ication Industry Association/
Electronic Industry Association ( TL9/EIA ) Teleco,.--"~"ications standards ofthe American
Telecol,,l,..l..ication Industry Association (TSB 40A), the connecting hardware used to lOOQ
UTP (Un~hiPl~le~l Twisted Pair) cabhng shall be installed to provide Ill;.. i.. ll signal impairment
by preserving wire pair twists as closely as possible to the point of mechanical termin~tion. The
amount of untwisting in a pair as a result ofterm:n~tion to connecting hardware shall be no
greater than 13 mm (0.5 in) for category 5 cables, and no greater than 25 mm (1.0 in) for
category 4 cables. This requirement is imposed to minimi7e untwisting of wire pair and the
separation of conductors within a pair.
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An additional cable management practice that should be observed to reduce untwisting of
pairs is to strip back only as much cable jacket as is required to termin~te on connecting
hardware.
The object ofthe present invention is to provide a structure ofthe telephone plug which
allows re~ ctinn ofthe amount of wire that is untwisted for termination, which enables to reduce
or even elimin~te Near End Crosstalk (NEXT), when data is transferred at frequency of 100 MHz
corresponding to category 5 connectors.
SIJM~RY OF THE INVENTION
Broadly, the present invention comprises a modular telephone plug comprising:
an in~ tion housing provided with a number of contacts mounted at one end or tip of said
housmg,
said housing having a hollow body comprising two portions,
wherein first of said two portions is adapted to accommodate
a cable comprising an outer in~ tion jacket enclosing a number of individual conductors;
a sleeve or liner provided to accommodate ends of said individual conductors e~tPn(ling from
said outer in~ tion jacket;
said sleeve is adapted to be placed into a second portion of said housing directly underneath of
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said contacts to facilitate successful electrical termin~tion of said contacts with said individual
con~ ctors accommodated within said sleeve,
wherein said sleeve is provided to elimin~te a near end cross talk when data is tr~n~m:~ted by
means of said telephone plug.
In another embodiment ofthe present invention, said sleeve comprises a hollow in~ tion
element having a number of inner grooves or channels adapted to accommodate each of said
individual conductors. Said channels are positioned parallel to each other and are aligned with the
corresponding contacts mounted in said housing, and said channels are positioned in the same
hori7.t nt~1 plan.
In yet another embodiment, said sleeve further comprises slots or recesses formed directly
above each of said channels; said slots are provided to facilitate s~lcces~fill piercing of said
individual conductors by means of said corresponding contacts during electrical termin~tion. Each
end of said individual conductors is completely accommodated within said sleeve, and wherein in
assembled position, said sleeve is abutting or flush against the tip of said housing.
In still another embodiment, said contacts comprising a number of blade-shaped element~
mounted near the tip of said plug in vertical position,
wherein upper edges of said contacts are adapted to be mated with corresponding female jack,
and wherein lower edges of said contacts are adapted to be electrically terminated with the
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corresponding individual conductors. Said housing further comprising a strain relieve element
adapted to securely grip the outer in.~ tion jacket inside of said housing to elimin~te any
undesirable shding of said cable out of said housing.
Tn yet another embodiment of the present invention, said strain reheve element is an
integral part of said housing, and said housing further comprises a metal shield mounted around
said housing to prevent an electro-magnetic interferences. Said housing and said sleeve are made
of polycarbonate m~t~,ri~l or the like.
BT~EF DESCT~IPTION OF DT~AVVINGS
Other objects and advantages of the present invention will be apparent from the following detailed
description of certain prerelled embodiments thereof and from the attached drawings of which:
Fig. 1 is a side cross-section~l view ofthe in~ tion housing ofthe present invention.
Fig. 2 is a top view ofthe in~ tion housing ofthe present invention.
Fig. 3 is a back view of the insulation housing.
Fig. 4 is a front view of in~ll~tion housing
Fig 5 is a top view of a sleeve according to the present invention.
Fig.6 is a cross-sectional view of Fig.5 taken along the lines A-A.
Fig. 7 is a back view of Fig. 5 showing a number of inner grooves or channels.
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Fig. 8 is a side cross-sectional view of the in.~ tion housing as of Fig. 1 provided with the metal
shield
Fig. 9. is a perspective view oftwisted pair cable.
Fig. 10 is a perspective view ofthe sleeve showing the first step of plug assembly.
Fig. 11 is a perspective view ofthe sleeve with individual conductor being placed within sleeve.
Fig. 12 is a top view of assembly before the sleeve is inserted into the housing.
Fig. 13 is a cross-sectional side view ofthe completed assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown on Figures 1 to 4 the present invention comprises an in~ tion housing 10
having a hollow body provided with two portions 20 and 22. As it shown on Fig. 1, portion 20 is
large enough to accommodate cable having an outer in~ tion jacket 34, wherein second portion
22 of the housing 10 is smaller and is provided to accommodate an insulation sleeve 14 shown on
Figures 5 to 7. The front portion or tip of the housing 10 is provided with a number of contacts
12 embedded into the housing 10. Each ofthose contacts 12 having a blade-shaped configuration
and are mounted near the tip ofthe housing 10.. The housing 10 also comprises a latching
mech~ni~m 16 provided to securely hold the plug inside the female jack and a strain reheve
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element 18 integrally formed in the housing 10. This strain relieve element 18 is provided to
securely grip the outer in~ tinn jacket 34 within the housing 10.
As it is shown on Figures 5 to 7, in~ tion sleeve 14 is adapted to accommodate ends of
individual conductors 30. The sleeve 14 comprises an elongated hollow body provided with a
number of inner grooves or channels 24 positioned parallel to each other. When the sleeve 14 is
inserted into the second portion 22 ofthe housing 10, those channels 24 are a]igned with the
corresponding contacts 12 mounted in said housing 10. Upper surface of the sleeve 14 comprises
slots or recesses 26 formed directly above each ofthe channels 24, those slots 26 are provided to
facilitate successful piercing of said individual conductors 30 by said corresponding contacts 12
during electrical termin ~tion. In this case, each end of the individual conductors 30 is completely
accommodated within the sleeve 14, wherein in the assembled position (see Fig. 13) the sleeve 14
is flush against the tip ofthe housing 10. Upper edges of contacts 12 are adapted to mate with the
corresponding female jack, and lower edges are electrically termin~ted with the corresponding
conductors 30. In the assembled position the sleeve 14 is positioned directly underneath of
contacts 12 to facilitate succes~fill electrical term:n~tion ofthose contacts 12 with the individual
conductors 30 accommodated within sleeve 14. Normally there are four twisted pairs of
individual conductors and the sleeve 14 comprises eight corresponding grooves for those
conductors 30.
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Another embodiment shown of Fig. 8 is similar to Fig. 1, except that the housing 10 is
additionally provided with a metal shield 32 mounted around the housing 10 and provided to
prevent electro-magnetic interferences.
Preferably, the housing 10 and sleeve 14 are made of polycarbonate material.
Figures 9 to 10 illustrate assembly procedure ofthe present invention including the
following steps:
stripping the outer jacket 34 of the cable 28 for a length of approximately 20 mm;
untwisting the individual conductors 30 and inserting them into the sleeve 14;
cutting the access conductor from the front ofthe sleeve;
inserting the assembled sleeve 14 and cable 28 into the housing 10, wherein the sleeve 14 should
be positioned directly under the contact blades 12;
terminating the completely assembled plug by means of a hand tool, or an auto-term:n~tion
tool (not shown), thus completing the operation.
The main advantage ofthe present invention is a structure ofthe telephone plug allowing to
reduce the amount of wire that is untwisted for termin~tinn, which enables to reduce or elimin~te
Near End Crosstalk (NEXT), when data is transferred at frequency of 100 MHz corresponding to
category 5 connectors. However, this structure is not restricted to category 5 connectors only and
may be used for other modifications or categories of similar connectors.
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It will be obvious to those ordinary skilled in the art that many changes may be made in
the details of the above-described pl~r~lled embodiment of the present invention without
departing from the spirit ofthe invention. Therefore, the scope ofthe present invention should
only be determined by the following claims.
