A. G. BELL.
`TELEPHONE CIRCUIT.
`
`No. 244,426.
`
`Patented July 19,1881.
`
`In/ve/r0357"
`
` /Mmfleé
`
`AMX
`Exhibit 1023-00001
`
`

`
`UNITED STATES PATENT OFFICE. ‘
`
`ALEXANDER GRAHAM BELL, OF VVASHINGTON, DISTRICT OF (iOLUl\IBL5i.-
`
`TELEPHONE-CIAIRCUIT.
`
`SPECIFICATION forming part of Letters Patent No. 244,426, dated July 19, 1881.
`(No model.)
`-
`Application filed Juno 4, 1881.,
`
`To all whom. it may concern:
`Be it known that I, ALEXANDER GRAHAM
`BELL, oi‘ W’ashington, in the District of‘ Go-
`lumbia, have invented a ne\v and useful
`lin-
`provement in Tclephonic 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—forn1ing 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 effect 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
`substantially equidistant, 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 outcr 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
`
`the wires against each other when the conductor
`or cable is stretched.
`With parallel wires, side by side, 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 difference 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 diifcrence is
`only at small fraction of the distance of either
`wire of a strand to the nearest \vires of adja-
`cent strands, and the unneutrali'/.ed current is
`inappreciable, 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
`sill: or cotton soaked in paraf-
`finc) between the \vircs of each strand and sur-
`rounding the pair with a much thicker coating,
`(such as tarred rope, gutta-percha, pcrite, 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
`ofcach 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 effect.
`Figure 1 represents one of the strands of the
`cable, the View being in 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 Ct Z) of each strand are small
`copper wires, equal in size. They each have a
`coating, c, of cotton or sill: soaked in paraf-
`finc, applied in the usual way. After being
`twisted together they are surrounded with a
`layer, d, of tarred rope, gntt-a~percha, or other
`suitable insulating material. A number of
`these strands are formed into a cable. As
`shown, they are bound together by an outer
`
`AMX
`Exhibit 1023-00002
`
`

`
`244a'12($
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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 Wliiieh they are to
`be placed.
`Having now fully described the said inven-
`tion and the manner of carrying; the same into
`effect, I 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 oneofsaid disturbin,2;-Wi1*es;
`20 nor do I claim herein the twisting‘ of the insu-
`lated wires of the metallic circuit for the pur-
`
`25
`
`pose indicated, for these 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 I reserve them for that ELppllC£1~
`tion ; but
`What I do claim herein, and desire to secure
`by Letters Patent, is—
`A cable composed of a n umberofstrands each
`consisting of two insulated wires arranged as
`set forth, the wires of each strand beingequidis
`taut, or practically equidistant, from the wires
`of other strands. substantially as described.
`In testimon.v'\vhereof I have signed this 35
`specification in the presence of two subscrib-
`ing witnesses.
`
`AliE_\'ANl)1llt Gl’ulIlAM' BELL.
`
`Witnesses:
`PHILIP MAURO,
`D. P. COWL.
`
`AMX
`Exhibit 1023-00003