Premise wiring system and components therefor

A premise wiring system for telephones and the like is formed by a three-wire flat cable one end of which is terminated by a plug, the cable having at least one jack connected thereto at a position spaced from the plug and possibly a splice joining cable segments. Both the plug and jack are configured to have first and second terminals each terminal having a mating first end and an oppositely-directed insulation-piercing conductor-engaging second end with the second end of the first terminals configured to engage the outer conductors of the cable while the second end of the second terminal is configured to engage only the center conductor of the cable so that, regardless of the changes in direction imparted to the cable, the plug jack and splice can be terminated thereon effecting proper connection regardless of orientation. The splice is similarly configured but contains three double-ended terminals which engage like conductors of adjacent cable segments.

The present invention relates to a system for providing on-premises wiring 
for telephone systems and the like and, in particular, to a system and 
appliances which can be surface mounted thereby obviating the need for 
snaking wires and skilled technicians for installation. 
The recent changes in the telephone systems in the United States have 
created the opportunity for individual building owners to create their own 
on-premises wiring for telephones and the like. This allows the owner to 
customize his building by putting telephone outlets at any desired 
location. Heretofore this could be accomplished but required a skilled 
technician to snake wires through walls, conduits or the like, and make 
all of the necessary interconnections. 
In my earlier co-pending application, Ser. No. 445,128 filed Nov. 29, 1982, 
and now abandoned, I described a system for providing on-premises wiring 
for burglar alarms and the like. At the time I suggested that the two-wire 
system disclosed therein could be used for telephone systems. This has 
proven not to be the case in that telephone wiring has some unique 
features. While telephone wiring traditionally utilizes a two-wire system, 
the wires are designated as ring and tip and must always be connected in 
this relationship. Problems are created when the twin line ring-tip cable 
is bent at right angles in the plane of the cable. This can be visualized 
by considering two parallel conductors coming down a wall and then turning 
in either direction, for example, to the left or right along the base of 
the wall. It will readily be appreciated that in this situation a turn in 
one direction will have the ring wire on top while a turn in the opposite 
direction has the tip conductor on top. This would therefore cause great 
confusion to an unskilled installer in attempting to wire a premises for 
telephones in that he would have to have his junction box right-side-up or 
inverted according to how the wire has been turned between the main 
interconnect and the desired site for a tap. 
The present invention overcomes the difficulties and confusions which might 
be caused in attempting to provide premises telephone wiring with a 
two-wire system. The subject invention utilizes a three-wire cable wherein 
the outer conductors have a total cross-sectional area equal to that of 
the central conductor. The conductors are preferably secured in parallel 
spaced configuration by a clear, insulative, profiled material provided 
with an adhesive backing. The individual system is completed by at least 
on jack and at least one plug, each of which includes a two-piece housing 
of insulative material defining a mating face, an oppositely directed 
cable passage and receiving therein at least two insulation displacing 
terminals one of which is adapted to engage the ring conductor and the 
other to engage both tip conductors, with each terminal having the 
opposite end profiled for mating with an appropriate member.

The subject premises wiring system 10 is schematically illustrated in FIG. 
1 with a wall jack 12, a plug 14 mated with the wall jack 12 and attached 
to a cable 16 which is laid out around the room with at least one cable 
jack 18 attached to the cable. At one location a plug 20 attached to one 
end of a cable 22, the other end of which is attached to a telephone 24, 
is mated with a jack 18. At one point cable segments are joined by a 
splice 26. The primary components of the subject invention, namely the 
plug 14, cable 16, cable jack 18, and splice 26 are shown in detail in 
FIGS. 2 to 8. 
The plug 14 is shown in exploded condition is FIG. 4 and includes a front 
housing 28 of rigid insulative material having a profiled mating end 30 
and an oppositely-directed rear face 32. First and second terminal 
cavities 34, 36 extend between the mating end 30 and the rear face 32 and 
are profiled at the rear face as shown in FIG. 6. The front housing 28 
also has a cable directing flange 38 at one end of rear face 36, a pair of 
apertures 40, 42 in the rear face 32, and a pair of latching lugs 44, 46 
on the sides of the rear face 32. First and second terminals 48, 50 are 
profiled to be received in the respective cavities 34, 36. Terminal 48 
includes a blade portion 52 having retention tines 54 extending therefrom 
and a pair of parallel arms 56, 58 extending normal to both the plane of 
the blade 52 as well as its axis. Each arm 56, 58 has an insulation 
displacing slotted configuration 60, 62, respectively, extending normal to 
the free end thereof. The other terminal 50 has a blade 64, latching tines 
66 and arm 68 with an insulation displacing slotted plate configuration 70 
on the free end thereof. The rear cover 72 is likewise formed of rigid 
insulative material and has a cable receiving face 74 with a blind cable 
groove 76 having slots 78, 80, 82 near the blind end of the groove 76, 
each slot being positioned to receive a respective insulation displacing 
portion 60, 62, 70 of a respective terminal 48, 50 therein. The rear cover 
72 also includes a cable directing end profile 84, a pair of mounting 
studs 86, 88, and a pair of latching arms 90, 92. 
The plug 14 is assembled as one might expect. The terminals 48, 50 are 
inserted into their respective cavities 34, 36 with the blades 52, 64 
being exposed at the mating end 30 and the insulation displacing portions 
60, 62, 70 exposed from the rear face 32 of the front housing 28. The 
cable 16 is placed in the groove 76 of the rear cover 72 which is then 
applied to the front housing 28 by inserting the studs 86, 88 into the 
respective apertures 40, 42. This causes the conductors of the cable 16 to 
be engaged by the respective terminals as well as to secure the cover 72 
to the front housing 28 by engagement of the latching arms 90, 92 with 
lugs 44, 46, and the profiling of the cable 16 in end 84 by flange 38. 
The jack 18 is shown in exploded perspective view in FIG. 5 and comprises a 
front housing 94 of rigid insulative material defining a front mating face 
96 and a profiled rear face 98. Cable groove 100 extends transversely 
across the rear face 98 of the front housing 94. Terminal slots 102, 104 
extend between the mating face 96 and the cable groove 100. The rear face 
98 also includes apertures 106, 108 and the front housing 94 has a pair of 
latching arms 110, 112. A pair of first and second terminals 114, 116 are 
profiled to be received in the respective terminal slots 102, 104. The 
first terminal 114 has a body 118 an end of which is profiled with a 
folded blade configuration 120. The opposite end of the body 118 has a 
transverse arm 122 at the ends of which are upstanding profiled insulation 
displacing slotted plate configurations 124, 126. The second terminal 116 
is somewhat similar in that it has a body 128 with a folded blade portion 
130 and a single insulation displacing conductor-engaging slotted plate 
configuration 132. The back cover 134 is also of rigid insulative material 
and defines a cavity 136 which receives the front housing 94 therein. A 
transversely extending cable groove 138 intersects the cavity and contains 
slots 140, 142, 144, each aligned to receive a respective slotted plate 
portion 124, 126, 132 of terminals 114, 116. The back cover 134 also 
includes integral studs 146, 148, latching shoulders 150, 152, and 
mounting apertures 154, 156. 
The assembly of a jack 18 is readily understood by those skilled in the 
art. The terminals 114, 116 would be inserted into their respective slots 
102, 104 so that the portions 120, 130 are exposed at the mating face 96 
and the insulation displacing portions 124, 126, 132 lie exposed in the 
cable groove 100. The rear cover 134 carrying the cable 16 therein in 
groove 138 receives the rear surface 98 of the front housing 94 with studs 
146, 148 being received in apertures 106, 108 and latching arms 110, 112 
engaging shoulders 150, 152. This action will drive the slotted plate 
portions 124, 126, 132 of the terminals 114, 116 into the respective 
conductors of the cable 16 to effect termination. The thus assembled jack 
can be mounted on a wall, panel, or the like, either by mounting means 
(not shown) passing through apertures 154, 156 or by adhesive means (also 
not shown) on the back of the cover 134. 
FIG. 6 shows a transverse section through a plug 14 and a jack 18, each 
terminated to a respective cable 16, and illustrates how they would be 
aligned and mated. This mating feature is conventional as shown in, for 
example, U.S. Pat. Nos. 4,186,988 and 4,193,654. The mating profiles of 
both the plug 14 and the jack 18 are preferably of an industry standard. 
FIG. 7 shows a splice 26 which would be used to interconnect lengths of 
cable 16. The splice 26 has a back housing 158 of rigid insulative 
material which defines a pair of oppositely directed, blind cable grooves 
160, 162, each having three slots 164, 166, 168, 170, 172, 174 therein. 
The back housing also has apertures 176, 178, latching shoulders 180, 182, 
and can be provided with wall or panel mounting means (not shown). Double 
ended terminals 184, 186, 188 each have body portions 190, 192, 194 with 
mounting members 196, 198, 200 and oppositely directed slotted plate 
portions 202, 204, 206, 208, 210, 212. The cover 214 is formed of rigid 
insulative material and defines terminal receiving recesses 216, 218, 220, 
mounting studs 222, 224, and latching arms 226, 228. 
The splice 26 would be assembled much in the manner of the above discussed 
plug 12 and jack 18. The terminals 184, 186, 188 would be mounted in their 
respective recesses 216, 218, 220. Ends of cables 16 would be placed in 
grooves 160, 162 and the cover 214 applied with studs 222, 224 entering 
apertures 176, 178 and latching arms 226, 228 engaging shoulders 180, 182. 
This drives the slotted plate portions 202, 204, 206, 208, 210, 212 into 
the cables 16 to terminate the respective conductors. 
FIG. 8 shows a cross-section through a cable 16 according to the present 
invention. It will be noted from this FIG. that the center conductor 230 
has a cross-sectional area which is substantially equal to the total 
cross-sectional area of the outer conductors 232, 234, preferably 0.0201 
inch or 24 gage and 0.0142 inch or 27 gage. The conductors can also be 
either solid or stranded. This cable is preferably formed by an extrusion 
process with the insulation 236 preferably being a transparent PVC ar 
similar plastic providing two advantages, namely ease of termination by 
allowing the conductors to be visually inspected when the termination is 
effected, and second, and perhaps most important to the homeowner, it 
tends to conceal the cable by allowing the color of the underlying surface 
(which could even be patterned wallpaper) to show through. The cable is 
also preferably provided with an adhesive backing selected from any one of 
the many adhesives available. 
The illustrated cable profile has also been found to be particularly useful 
in maintaining alignment of the conductors as the insulation is extruded 
to form the cable. 
It will be appreciated from the foregoing that, when the cable 16 of the 
present invention makes a turn to either the right or left in the plane of 
the cable, the relative orientation of the conductors will stay the same. 
Thus the ring conductors 232, 234 will always be on the top and bottom and 
the tip conductor 230 will always be in the center, thereby obviating any 
need for the installer to determine which of two conductors is tip and 
which is ring and install the plug or jack with the proper orientation.