A. G. BELL.
`TELEPHONE CIRCUIT.
`
`No. 244,426.
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`Patented July 19,1881.
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`Aerohive - Exhibit 1023
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`UNITED STATES PATENT OFFICE."
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`ALEXAl\*DElt GRAHAM BELL, OF W’ASHlNGTOI\", DISTRICT OF COLlTl\~lBI.-’I.-
`
`TELEPHONE-CAIRCUIT.
`
`SPECIFICATION forming part of Letters Patent No. 244,426, dated July 19, 1881.
`(No model.)
`»
`Application filed -Tune -1, 1881..
`
`To all whom it may concern :
`Be it known that I, ALEXANDER GRAHAM
`BELL, ct‘ VVashington, in the District of Co-
`lumbia, have invented a new and useful Im-
`provement in Telephonie Circuits, which im-
`provement is fully set forth in the following
`specification.
`This invention relates to cables for telephone
`transmission, and has for its object the pro-
`duction of a cable in which the circuits are so
`arranged that no disturbance will, in use, arise
`from their inductive action upon one another.
`The several circuits are composed each of two
`wires—a direct and a return wire—forming a
`metallic circuit.
`Inductive disturbance in the telephone and
`in other electrical instruments connected with
`a metallic circuit when the latter‘ is placed in
`the neighborhood of other electrical circuits
`arises from the unequal inductive eflect of the
`latter upon the two wires, for it is obvious that
`if the direct and the return wire were affected
`equally the current generated in one would neu-
`tralize and destroy that created in the other.
`The disturbance can be avoided by placing the
`two wires in the same inductive relation to the
`disturbing currents, or, other conditions being
`the same, by placing them at equal distances
`from the said circuits. This desired result is
`accomplished in the present invention. The
`two wires of each circuit are equidistant, or
`substantiallyequidistant, from every other wire
`in the cable.
`The wires which are to form the metallic cir-
`cuit are covered, one or both, with insulating
`material, and after being placed together are
`embedded in or surrounded by insulating ma-
`terial. The outer layer of insulating material
`may in some cases be dispensed with, but in
`all cases the wires of each pair are insulated
`' from each other and from all the other wires,
`and are bound together so as to form one strand
`of the cable. Any desired number of strands
`' are united or held together in any ordinary or
`suitable way. The two wires of each strand
`may be laid side by side or they maybe twisted.
`The twisted wires are preferred, as giving the
`most perfect freedom from inductive disturb-
`ance, although they are more liable to become
`injured by handling than the other form on
`account of the pressure and rubbing action of
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`the wires against each other when the conductor
`or cable is stretched.
`With parallel wires, side byside,it is obvious
`that in a cable composed of numerous circuits
`the two wires of each strand will not be abso-
`lutely equidistant from every one of the other
`wires; but the difiereiice in the present inven-
`tion is made of no practical
`importance by
`placing wires of each strand very much nearer
`to each other than to those of any other strand,
`so much nearer, in fact, that the difference is
`only a small fraction of the distance of either
`wire of a strand to the nearest wires of adja-
`cent strands, and the unneutralizcd current is
`inappreciablc, or does not create serious dis-
`turbance.
`The desired relation of circuits is secured by
`providing a very thin coating of insulating ma-
`terial (such as sill: or cotton soaked in paraf-
`fine) between the wires of each strand a11d sur-
`rounding the pair with a much thicker coating,
`(such as tarred rope, gutta-percha, perite, or
`india-rubber.) VVith twisted wires the relative
`distances of the wires is of little or no conse-
`quence, so far as obviating inductive disturb-
`ance is concerned, since by the twist the wires
`ofeach pair are brought alternately to the same
`position relative to the other wires. Where
`both wires of each strand are well insulated the
`external envelope ofthe strand may be omitted,
`but it is preferred to surround the twisted wires
`as well as the parallel. wires with insulating
`material.
`The accompanying drawings, which form a
`part of this specification, illustrate what is
`deemed the best method of carrying the inven-
`tion into efl’ect.
`Figure 1 represents one of the strands of the
`cable, the View being i11 elevation, with the in-
`sulating-layers partly cut away to show more
`clearly the construction. Fig. 2 is a view, in
`cross-section, of the improved cable.
`The two wires It b of each strand are small
`copper wires, equal in size. They each have a
`coating, 0, of cotton or sill: soaked in paraf-
`fine, applied in the usual way. After being
`twisted together they are surrounded with _a
`layer, (7, of tarred rope, gutta-percha, or other
`A number of [O0
`suitable insulating material.
`these strands are formed into a‘ cable. As
`are bound together by an outer
`shown, they
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`covering, 0, which is or may be of rope, Wire,
`or a combination of materials.
`Cables constructed in accordance with this
`invention may be used above ground, under
`ground, or under Water, and the details of con-
`struction can be modified to adapt them to the
`particular circumstances in which they are to
`be placed.
`Having now fully described the said inven-
`tion and the manner of carrying‘ the same into
`effect, 1 would observe, in conclusion, that I
`do not claim herein, broadly, as a means for
`obviating the inductive disturbance of elec-
`trical circuits upon each other, the arrange-
`ment of two Wires constituting‘ a metallic cir-
`cuit in the neighborhood of disturbing-Wires
`so much nearer to each other than to any ofthe
`disturbing-wires that they are practically equi-
`distantfrom every one of said disturliing;-Wires ;
`nor do I claim herein the twisting; of the insu-
`lated wires oi‘ the metallic circuit for the pur-
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`pose indicated, forthese matters I have claimed
`in my application for Letters Patent for im-
`provements in telephonic circuits filed June
`10, 1878, of which the present application is a
`division, and 1 reserve them for that applica-
`tion ; but
`What I do claim herein, and desire to secure
`by Letters Patent, is—
`Aeable composed of anumber of strands each
`consisting of two insulated wires arranged as
`set forth, the wires of each strand being equidis-
`tant, or practically equidistant, from the wires
`of other strands. substantially as described.
`In testimonylwhereof I have signed this 35
`specification in the presence of two subscrib-
`ing witnesses.
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`1lIiE.\'Ai\"l)El’t GRAIIAM BELL.
`
`Wi tn esses:
`PHILIP MAURO,
`1). 1’. Gown.
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