US864713A

US864713A - Telephone repeater system.

Info

Publication number: US864713A
Application number: US35403907A
Authority: US
Inventors: Nathaniel G Warth
Original assignee: Individual
Current assignee: Individual
Priority date: 1907-01-25
Filing date: 1907-01-25
Publication date: 1907-08-27
Anticipated expiration: 1924-08-27

Description

PATENTED AUG. 27, 1907.

NP G. WARTH.

TELEPHONE REPEATER SYSTEM.

APPLICATION FILED JAN. 25, 1907 FULL NATHANEEL @WARTH PATENTED AUG. 27, 1907. N, WAR TELEPHONE BEEPEATEE SYSTEM.

APPLIGATION FILED 5103.25, 1907..

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A2 xc amewtoz MWMATHANIEL G.WARTH UNITED sTArns PATENT, OFFICE.

NATHANIEL G. WARTH, O F COLUMBUS, OHIO.

TELEPHONE REPEATER SYSTEM.

No. sos'. -n a.

This invention relates to improvements in telephone current repeaters or relay re-inforcers and systems for their operation ofthe general character illustrated in the United States patents to Herbert E. Shreeve,.as

follows: Nos. 791,655 and 791,656 dated June 6, 1905,

and 835,037 dated November 6, 1906, and isa modified form of and analogous in its major principles to the repeater apparatus and system discolsed in my patent of the United StateaNo. 845,282, dated February 26,

' repeater for the purpose of preventing the local self-v action lrnown aslfhowling, or singing; efiecting The present invention like that covered by my patent above reierred toinvolves conditions of operation and" accomplishes beneficial results in providing a constant balance for the repeater apparatus, regardless of the staieof balance of the line circuits connected with the the elimination of auxiliary coils and condensers, de-

rived or balancing circuits, drc., which interfere with transmission by producing distorting reactive currents and cause an unnecessary dissipation of the current.

The important feature of my present improvement is thearrangement and location of the line repeating induction coil windings in the sectiohs oi the line cir' cuit, whereby direct through or original transmission from the transmitting station is reduced to a minimum.

This condition is also largely contributed to by my use of a very low resistance 3 bridge betweemthc two sides of the line, in which no repeater coils or windings are included, and which contains no repeater apparatus, but when the line circuit is also used for composited service, which combination is with this repeater syste'ih especially contemplated, a condenser may be included in the bridge. This arrangement, together with my combination of divided or bridged local circuits, effects a condition of minimum direct transmission across the repeater station of tlie system, thus insuring singlencss of action and giving a clear reproduction and amplified re-tmnsmission into the receiving end orsectionof the two sectionsohline circuit. This system, it will be noted, is also similar to that embi-aced in my patent mentioned above, in that the ire-transmission being divided is effectedsimultaneously in both directions or line circuit sections.

'Another important object of the present invention is to secure an equalized transmission toward each terminalstntion, and particularly to prevent a line section oi 'low resistance from taking a disproportionate amount in the retransmitted current, each line section thus re- Specification of Letters Patent, Application filed canary 25 1907. Serial No. 354,089-

Patented Aug. 27, 1907.

separately and equally in -each line or circuit section, 6=

and being confined therein by the low resistance bridge. The resistance of the associated circuit and its coils offers an additional barrier to overflow or direct transmission from line section to line section, and these conditions in association. with the dividedlocal circuits, 7;

to be described hereafter, practically prevents such action and also that of the initial or originating currents being conductively transmitted into the associated section of line circuit past the repeater. These conditions produce the hereinbefore mentioned singlcness of ac 7i; tion or effect upon the repeater-receiver, and effectually avoid echo like reaction currents,and distortions of the currents by the repeater apparatus.

While. the invention chiefly. consists in the above features it further consists in the provision of a 8O culisrly'arranged composite toroidal form of repeating induction and retardation coil, whereby and wherein reactnnce orret a-rding effects are minimized for the telephonic or voice currents, and also for any direct or through transmission of composited or superposed ofi currents applied to the same line wires. For the latter class of service the invention also consism in auxiliary apparatus an circuit arrangements associated with the composite coil whereby phantom circuit' or additional superposed currents, or service,

is especially provided for and enables the phantomed telephone (or simplex) transmission to pass the repeater station without interference and with no interference 5 to the other simultaneous transmissions. This special induction coil is the common or dualmeans for the operative association of the repeater apparatus with the line circuit or circuit sections for both the receiving and re transmitting currents. The secondary windings of the coil are preferably divided into four helices,

J'LWO of which are symmetrically disposed on quarter 10(':

sections, on each half of the ring core, each pair of windings being differentially but conductively connectcd together in the through line circuit serially,

. one winding or helix on each side of the bridge, on each side of the line. These windings are the secondary or main line windings oi the coil, and are traversed-by the 1 elephonig: or voice currents, the telephonicsignaling or ringing currents, and, when the circuit is utilized for superposed or composited sen-ice, also for those ii'urrents, whether they be direct, pulsating 0r alter 11G uating in charactr. r i I When ringing currents, composited telegraphic, or

signaling currents, are transmitted, either alone or simultaneously with the telephonic currents, the repeater apparatus being in circuit, is ordinarily subjected to more or less violent and undesirableaction. This action. or effect in my arrangement is practically overcome, or rather is avoided by the differential windings referred to above, and which will hereinafter hemore particularly explained in connection with other features of the arrangement of the coil and its cohnections.

A great desideratuni in connection with extending the range oi telephonic transn'iissien by means of a repeater, is the flexible use of the apparatus by the ordinary switching operators. whereby with a repeater apparatus installed in a cord circuit", operators may arbitrarily or without any fine discriminationas to the resistances or other peculiar conditions, connect two circuits togethcr. as rcadily is ordinarily the operation of connecting two lines; or with no more judgment or effort on their part than is usual when a connection is established by including an ordinary repeating coil in a through circuit. The equal division and predetermining of the division or (tree-- tion of the re-transinitting currents in the two circuit sections, together with the condition of constantly nmintained balance of the repeater receiving element against local action, renders my repeater arrangement highly eliicicnt and peculiarly adaptable to such general switching service.

For economic reasons "long distance circuits are frequently used for coirposite service, that is, telephoning. tclcgraphing, signaling, do, sinultancously over the same wires. Usually the telephone circuit is operate-(l as a metallic circuit, and the other or superposcd circuits as "grounded or earth-completed circuits. To adapt my repeater system and apparatus.

n u I with condensers inserted at the middle of-the secondary to such combined or composited service, and to do so with a minimum of mutual interference, and as a pro ict'iion to the repeater apparatus proper, it is desirable to affect the clliciency of transmission of the superposed currents as little as possible, and to shield the repeater apparatus from action by the non-telephonic currents. As. the repeating induction coil secondary windings are included in the line circuits in this instance, the superposed currents are transmitted there through. Such currents being usually of low frequency and great volume compared with telephonic currents, have time to quite thoroughly magnetize a core of the character used in such a coil. Such a core effect would caus the coil to seriously retard tht superposed currents, especially since they must traverse two windings, one on either side of the bridge. Such an effect would tor would not, according to the current frequency also set up or croatean undesirable action upon the repeater receiver-transmitter. Both undesirable ef ects 1 practically overcome by connecting the two windings non-inductively, or differentially, to the through superposed currents and without ai'hctin; the telephonic currents because their circuit is completed through the bridge and passes through the windings in their line circuit section side of the bridge onlytas will be more particularly explained. Certain other ad virntages also accrue in this respect by utilizing the various windings of the composite coil to render the non-telephonic currents harmless to the repeater apparatus. Ringing currents, as with the telephonic cuirents, are usually applied to the metallic circuit, and their violent action would operate the repeater injuriously. This effect can be practically avoided by connecting the two telephonic .windings of the coil, that is, one winding in each conductor on the same side of the bridge, non-inductively or differentially. Low frequency ringing currents in this in: stance'would produce a neutral field or core effect and not. set up a strong induced current to violently affect the receiver element of the repeater in its local circuit,

because the local windings are in neutral inductive relation to the secondary or telephonic windings. higher frequency telephonic currents however, due to the magnetic reluctance of the core, produce efficient converting action by reason of the windings creating The or elementary form and developments of that form to l the preferred form, such drawings being so made to facilitate an understanding of the physical and superposed circuitsand the composite coil connections.

Figure 1 is a diagram illustrating a compound circuit for a telephone repeater composed of two line circuit sections conductively ending at a repeater station in a repeating induction coil, with a winding each upon the same core and also representing a local or primary circuit with its winding upon the core; Fig. 2 is a diagram illustrating a similar compound circuit, but equipped windings of the repeating induction coil, conductively or physically separating the two sides of each line circuit section, and with inductance or retardation coils physically connecting the circuit sections on each side, thus providing for superposed direct or through transmission on each side of the compound circuit; Fig. 3 is a diagram illustrating such a compound circuit provided with a composite retardation and repeating induction coil and a condenser which together fulfil, in a simplified way, all the functions of the apparatus and arrangement shown in Fig. 2 for both the telephohic repeater and composite services; Fig. 4 is a diagram representing the invention, part cularly as to the telephonic or repeater conditions, illustrating my combination of divided repeater circuits, embracing the main or compound through circuits with the low resistance bridge; the repeater-receiver circuit in which the receiver is operated inductively by the initial transmission from the terminal telephones, and is in a state of maintained balance against, and inert to, its jown repeater-transmitter currents; and the split or divided repeater-transmitter circuit, having the battery or current supply, and'the repeater-transmitter element included in the dividing conductor of the circuit; Fig. 5 is a diagrammatic representation of a complete com pound repeater circuit arranged for composite service, and having asc iciated therewith the composite coil,

which fo clearneds is illustrated with each of the plural windings on separated sections of the .ring

core, the primary and the tertiary windings being the main line circuits of the system with the associated apparatus therefor, embraunia flexible cord-circuit and, in addition to the telepli nic, repeater and com.- posite circuits, an arrangementlior a phantom circuit, or a special simplex circuit, alsoinductance and inductive shunts around the epeater for particu lar operating and service purposes.

In Fig. 1, as in all the views, L and L signify two sections of a metallic telephone circuit, or two metallic circuits, which in each case are assumed to be inductively joined with a telephone-repeater apparatus. I

In Figs. 1, 2 and 3 the coil windings 0, G &c., represent the secondary windings for" the repeater and Po the primary windings. r W and W signify one side of the through circuit, and W and W the other side of the circuit; W and W and W" and W, corresponding to the L and L sections respectively, in all the views, offthe composite circuit. OX signifies the core of the repeating induction coil and is shown in dotted outline in Figs. 1, 2 and 3.

My invention, as the views throughout show, contemplates the division of the through compound circuit into two telephonic circuit sections, each section being complete and terminating at the repeater station,

wherever it happens to be connected or included in said through circuit by means of its repeating induction coil winding or windings, and this termination comprehends the connection between the windings when they are separated by a short conductor, which may include a condenser, :as is shown in Fig. 2.

In Fig. 2, Dreprcsents the short conductors and J and J 2 condensers in same, connecting the inner terminals of the coils 0, C and coils G 0, respectively. To adapt a circuit, so physically separated, to direct or through transmission across the repeater station, especially' for forms of direct current telegraphic service, the circuit sections L, L are connected together around the repeater apparatus or station, by the use of conductors A, A, in which suitable inductance or retardation coils F, F are included, as shown in Fig. 2. These coils F, F serveto preserve theseparation of the circuit sections telephonically yet permit the passage of direct or low frequency, &c., currents.

The condensers J, J are required to separate the two sides of the circuit when the composite service, by which is meant thesuperposed currents, is separately operated on the two wires or sides of the circuit, as is illustrated in Figa, 51 and 6. Suchcurrents, as is well known, are practically stopped by a condenser,

' but such condenser will permit the passage of high frequency, &c., currents. To simplify the apparatus for use in such combined service, and also for special adaptation to the fleriblc handling and use of the cirunits, as will he set fault in further description of Fig.

6, I prefcrto use the.a. rrangement shown in Fig. 3;.

In Fig. 3 the repeating induction coil has the windings O, C and (J C, pn eachhsidc respectively of the circuit, connected together to form therethrough a conductive through circuit, the windings so connected.

being differentially associated and serving'also as inductance coils in lieu of the coils F, F which arehere omitted. The short conductors D of Fig. 2 are, by this method of connecting the windings together, re placed by the short connection or bridge H, in which a single condenser J may be utilized to advantagein lieu of the two separate condeusersoifsaid view. Thus arranged the several circuits are oplatively as distinct" as when physically so. I

The coils in l, 2, and 3have cores of the usualv straight bai; or open circuit form, and while such coils are not ordinarily as effective as coils having the ring 7 or closed circuit form or" core, the bar or openform of core has, when provided with the separated sectional winding shown and, described, the same functions as my special toroidal type of coil, which is divided into distinct plural electro-magnetir;sections for independent sectional core effe cis. p

In Fig. 4, the two circuit sections L, L together with the terminal, stations S, SE and the repeater equipment at the intermediate station, comprise a complete telephonic system for long'distance communication requiring repeater service. In this view the coil windings are arranged inrcooperative relation and straight series connection; i

The flow of the currents are conventionally shown as follows: primary currents by short'solid arrows;

initial or repeating line currents by longsolid arrows;

and reproduced or repeated line currents by broken arrows. An initial transforming line current'being set up at the telephone S would at the intermediate or repeater station, traverse the repeating induction coil windings C 0, and the low resistance connection or bridge H, and would induce current (also indicated by long solid arrows) by means of the tertiary windings 'l T, in the half G of the repeater receiver ('l) circuit, 'thus energizing said receiver. Neither the initial currents from the line, nor the currents induced therefrom, in either. the primary or the tertiary windings or circuits, penetrate their respective associated like windings or circuits, by reason of the low resistance dividing cross-conductors 0r bridges H, P and TX, respectively. The receiver T winding, of the repeater apparatus It is connected into the bridge conductor TX, and the transmitter M of the repeater apparatus R, together with the local batteryB, are connected into the bridge conductor P. Thc'energizing of the receiver actuate-s the transmitter M, the two elements being in repeater relation to cornprise the repeater apparatus It, which varies correspondingly the resistances of the divided primary or local circuits and enables battery B to set up reproloo duced currents in facsimile, to flow through the four I circuit G, G.

would cause a current flow in the secondary windings of the induction coil SC upward (in the diagram), thence to the left in the line conductor W thence through'winding C of the repeating induction coil, thence to thejunction with the bridge conductor H, thrdugh the bridge to the junction with the line conductor W thence to the right to and through winding C of the repeating induction coil, thence to the point of starting at terminal telephone S The pass ing of the current through the windings C 0" would induce a corresponding current to flow oppositely (see the inner long solid arrows) in the associated tertiary windings 'l T, and that circuit as follows: Beginning at winding T at the top, flowing to the right thence downward, in the G2 circuit, thence to the left toand through winding T at the bottom to the junction with bridge conductor TX, through the bridge and receiver T therein, to the top junctiorr'of the bridge with the G circuit and to the right to and through winding T? the startirig point. The receiver T being thus energized and actuating'the transmitter M would set up a primary reproducing current flow as follows: Starting from the positive pole of battery B, in the bridgeconductor P upward to and through the transmitter M thence upward to the junction of the bridge with the B", B" sides of the primary circuit. At said junction the current divides, flowing to the right through the B circuit to and through the primary winding P associated with line windings C ll'lGllCO around to and through the winding P asse ciatcd with line winding 0 thence to the junction with the bridge P and thence to the negative pole of the battery. The other portion of the current flows to the left from the dividing point through the B circuit .to and through the primary winding P associated with line winding C, thence around to and through the winding P" associated with line winding C thence to the junction with bridge P. where it unites with the other current. The flow of this battery current through the primary windings induces a facsimile current in all the windings associated, and this induced current flows in the opposite direction to the inducing current (soothe directions of the broken and short solid arrows respectively). For the line circuits, the broken arrows are shown in the reciving or L section only. This particular secondary current is confined to that section of the circuit, the flow beingclearly shown by the broken arrows, as follows: Starting at winding C flowing? to the right to and through the bridge H thence to the left through coil thence through line conductor W to the terminal telephone at statioir S thence returning through line conductor W to and through winding Oto the starting point. A like flow occurs in the associated circuit section If, which under the circumstances is dissipated energy. Simultaneous and analogous inductive effects are produced in the divided tertiary The same broken arrows at the four '1 windings represent the induced current in this circuit.

It will be observed that the primary windings P, P in the B side of the primary circuit'are so connected that-the battery current flows to the left, as is also the direction of its flow in windings 1?,1", on the B side of the circuit, This arrangement, without changing the straight connections for the associated windings the L side of the repeater, produces a flow of the'iri} duced current in the tertiary circuits in the same direction, (see the broken arrows directed to the right at the top) down at the right and to the left at the bottom, thence up at the left and down throngh tho bridge TX and receiver T on the left side of the bridge conductor, thence up through the bridge and receiver on the left side of the bridge conductor. As the two sides of the circuit are balanced and the induced currents therein are also balanced, a condition of no difference of potential through the bridge is produced, resulting in no actual flowoi current in the bridge and the receiver '1, which neutral state, to the re-transmitted currents, leaves the receiver unenergized and silent, and the transmitter inert. It should be understood that the reciprocal of these current flows and effects occurs with each change in the direction of transmission or use of the line.

The arrangement of practical division of the main,

tertiary and primary circuits effectually prevents interfering reaction currents and effects, which in other repeater systems are present and cause distortion of the reproduced currents by out-of-phase or echo-like overflow or reactancc currents, due to direct transmission into the section of the circuit then receiving, hence each circuit section, main and local, and the apparatus as I describe it operates as independently as would be the case were the circuit sections physically separated, (which is also within the scope of my invention) and the resulting transmission is as directly induced into each line circuit as is the initially produced transmission at the terminal telephones.

Reaction currents and their interfering effects, as referred to herein, are particularly explained inflmy patent above referred to, as also are theconditions Fig. 5 is adapted particularly to an explanation of the composite repeating induction and reactance coil, and to the composite service conditions heretofore mentioned. This induction and reactance coil is-preferably of toroidal form with the core OX composed of a bundle of No, 22 annealed soft iron wires, as is now which crcatethe self-action effects producing howlingp usual with good forms oi repeating and induction coils,

and the coil should be closely covered with a soft iron shcll or casing to concentrate the stray field and for protcction against injury. The windings can ,be of 2 any gage of wire and number of convolutions adapted to the desired use. The primary helices P should be wound next the core, each of the four sections equally positionedon quarter divisions of the common core. For usual service conditions the "winding for each section should consist of about one hundred and fifty turns of N o. 19 gage double cotton-covered copper wire. The twoputr helices on each section may be so arranged that the tertiary windings are either outside or between the primary and secondary helices, or they may be alternately positioned if the number '0': turns around the core are compensated. Each helix should consist of about twelve hundred turns-of No. 27 wire, and the resistance through two windings inseries should not exceed one hundred and'fifty ohms. In said view the primary helices are-the inner or core windings, the secondary-windings C, G, G" and 0 are in the centerand the tertiary windings'are outside.

- 7 these small magnetic fields are made more intense and I efficient for this condition by the provision of theiron I local circuits. Across the diameter of the coil, at right angles to the before mentioned direction, the secondary windings on each side are also differentially connected, C with C and C with C, which provides for a minimum of inductive action to the repeater local circuits, and consequent vidleric'e to the apparatus, from strong currents circulating in either line circuit section, as previously explained. The four tertiary windings T correspond to thefour secondary sections, and as suggested above can therewith be interchangeably alternated or associated. The windings, however,- can under other circumstances be of larger wire, as their function isto operate the receiver T, which is in a low resistance local circuit. The receiver may also then be wound with larger wire with some advantage. The.

application of the tertiary windings to the receiver T 'circuits, is such, on each side of the bridge, theta telephonic-impulse :in its secondary windings irom a line circuit section, will induce a cooperative flow oi current in the two windings ('l"), the current being shunted through the bridge TX and receiver T by reason of the low resistance of the bridge. The local fields created in the coil by thetelephonic currents having been explained, it remains to be stated that shell referred to, which concentrates the stray field in each section by providing a short return circuit. This is true particularly with reference to the differential conditions. The four primary windings are also differentially connected on each side of the bridge, in this instance, bridge P, and the inductive "actions are similar owing to the rapid variation of current which the transmitter creates" in the battery circuitsB B and correspondingly energizing the windings.

The several local conditions and effects are similar to those described iii-connection with Fig. 4. While the differential connections are preferred, thrbughout the several ,c .uits, yet it is practicable to vary them without departing from the essential features of the invention, The primary windings may be connected cooperatively throughout or cooperatively on one side and differentially on the other, and-the tertiary windings maybe similarly vgried. With the receiving ele- I mont. T of the repeater apparatus R, I prefer to employthopermanent mag'netU for establishing its residual or initial magnetic field forsensitization, In this I {.iziiw the'superposed service is adirect cu'rrent telegraph circuit on each side of the through line circuit, which arrangement is usually termed composite as distinguished from simplex and phantom. The conductive separation of the circuit sides is effected at the repeater station by condenser J; at the terminal station S by condensers J, J; and at the terminal station 8' by condensers J, J, the telephonic circuit sections being, in this instance, the some as in Fig; 4,

with the exception of these condensers. The tel graphic circuits have cornmouground connections in E and E", and common sources of onergyin'batteries TB and T13 The lower circuit in this view is defined as follows: From ground E to and through bat tery 'll-l, thence to junction Y of the battery tap, thence to instrument h, line wire W, coils C, 0, line wire W, instrument K battery tap Y", T13 ground 15 and earth return. The upper circuit is similarly defined between Y and Y by way of the earth, thence from Y to instrument K, through line wire W, coils C, C, line wire W iustrumentnKi, and

thence to Y*.-

In Fig. 6 the repeater local circuits and apparatus are eliminated, as the scheme of this diagram has to do particularly with the conditions of circuit and appamtus for connecting the repeater secondary circuit into the line circuits and with the operation of the 8 superposed circuits past the repeater. The terminals of the two telegraphic circuits are omitted to avoid detail. 7 The flexible operation of the repeater by means of cord circuits is illustrated in this view, the outer terminals of the four secondary windings, G, C, 8 C, 6, being connected by cord conductors, Q, Q"), Q. Q, to plugs V, V, V", V, thence to thc line c0n ductors W, W W W, by means of the jacks 0, O 0", O, allrespectively. In practice the cords, plugs and jacks would be of the usual combined form for metallic irc'uits and similarly associated on each side the repeater, and with other equipment details well understood by those skilled in the art andv unneces sary to illustrate. For economy in apparatus and simplicity of operation it is preferred that the sec- 9 ondary coils and the cord circuit equipment shown in the view shall be withdrawn from the through line circuit, for composite service use, but when, the re pcater is not required for that same through circuit, I provide the auxiliary conductors A, A, and A, A, on each side of theeircuit. containing proper inductance coils F, F? By this arrangement the slow acting superposed currents may traverse both the repeating induction coil windings and the auxiliary coils on each side of thocircuit, thus securiug'a'more 1 efficient circuit, and when sensed such division of the superposed currents offers additional safety to the repeater apparatus. Should the secondary windings be required to operate cooperatively, or should it be desirable to prevent heating of the apparatus from the 1 strong superposed currents, such through currents may be caused to. be transmitted through the auxiliary conductors by inserting condensers in the cord circuits. The foregoing provisions of the cord circuit, and auxiliary apparatus, permits circuits to be ,used 1 for the ordinary long distance telephone service when not required for through or repeater service, and also permits various similar repeater connections to be established between circuits at a station having repeater battery equipment. In practice the line circuits may be terminated at a test board where the composite appar' tus is lpcated and connections are usually made and the lines then extended to the switchboard for the regulart'elephonic operation. The superposed telegraphic currents in this instance have their circuits, 12 b as explained in connection with Fig. 5,-excepting that at the repeater station they are passed through the secondary windings i the composite coil, and through the auxiliary conductorsi- ,At the terminal stations S and S, the receivers N,

N are connected at the middle of their windings with conductors X0 and X0 respectively, leading to apparatus X and X respectively, which, as herein stated, may be either telephonic or telegraphic apparatus operated by high frequency currents. If the apparatus used is telephonic, the connections leading out on the opposite side to the dead ends XE and XE respectively, would connect with another'and parallel telephonic circuit, while if the apparatus is telegraphic in character the connections may be with another circuit, or with the earth, or otherwise; sufiicc it to state that sucha superposed circuit is termed a phan torn circuit if telephonic or a simplex circuit if telegraphic in character. If a current impulse is set up at instrument X assuming it to have a positive flow through the system as shown to its corresponding station X, it will pass through the conductor X0 to the middle I connection with receiver N, where it dividesand flows differentially through the split windings of said receiver, and thence each half of the current will pass along its respective circuit as follows: The half passing upward through condenser J- will follow conductor W I to its junction with the auxiliary conductor 1 thence along that conductor passing through condenser .l in circuit in conductor I, to the junction of conductor Itwith line conductor W thence to and through condenser J 5 and the lower winding of receiver N, thence through conductor X0 and instrument X to XE, and finally completing its circuit back to X by any path that may 'he provided for it as indicated above. The other half of the current will find a likepath from receiver N" through condenser .l", line conductor W; auxiliary conductor I and its condenser 1 to and through line-conductor W, and condenser 1 thence telephone S or 8*.

posite apparatus.

differentially to the first half through receiver N to and uniting again with the first half. Such currents will not affcctthe telegraphic or telephonic apparatus, as already sufiiciently described herein, excepting as IfollowsrThe telegraphic apparatus first described is too sluggishin action to respond to the character of currents applied to this additional circuit, and such currents are unable to penetrate the retardation coils usually associated with the telegraphic apparatus (not sion into the receiving line circuit from either terminal; As an additional precaution against such action condenser .l in the bridge should be of ample clcctro-static capacity.

What I claim and desire to secure by Letters Patent 1. In a telephone system for the reproduction with increased power of the initially transmitted currents from terminal telephones, the combination of a telephone re pester receiyer-transmitter, a main circuit, and 'a bridge at the repeater station'dividing the main circuit into two circuits or two associated repeater line sections; u repeatingindnction coil at the repeater station having sectlonally divided plural secondary and local windings, and

semis having the secondary winding divided between the two sections of the main circuit with said bridge connected to each side of the main circuit between said divisions of the winding; 21 local circuit embracing, a part of said plural local windings for the repeater-receiver and a local circuit also embracing a part of said plural local windings for the repeatentransmitter, each said local circuit having a bridge dividing its plural windings, said plural windings being wound to correspond with the said secondary windings and adapted to produce substantially equal effects through said local circuit bridges, and all thewindings in each division of said coil being mutually inductive: the repeater-receiver and the repeater-transmitter being in circuit in the bridges of their respective local circuits, and a battery also in the local circuit containing the repeater-transmitter;

said repeater-apparatus being sensitive to the inducing initial line currents from each line section but insensitive and inert to its reproduced currents in the line sections, and to prevent local self action.

2. In a telephone repeater system, the combination of 11 repeater apparatus, a main telephonic circuit, a main bridge dividing said circuit, a repeating induction coil having its secondary in said circuit, windings of snid secondary being included in said circuit on each side of said bridge, local circuits for the receiver and transmitter of said repeater appnratusylocal bridges dividing said local circuits, the divisions thereof being electrically bulanced, and each containing local windings of the said 'coil associated with respective secondary windings thereof,

one of said local bridges containing the repeater-receiver and the other local bridge containing the repeater-transmitter and ubattery, means for rendering the receivertransrnitter operative inductively to the received currents, but inoperative to the local and reproduced currents.

3. In a telephone repeater system, the combination of 'a repeater apparatus consisting of a receiver and a transdnltter ln repeuter relation, a line circuit consisting of two circuit sections each inductively associated with said repeater receiver and transmitter, local circuits for the local self-action and against unbalanced line circuit e f:

fects.

4. The combination. in a telephone repeater system, oi.

a receiver-and transmitter associated in repeater relation,

a repeating induction coil having plural windings both secondary and local. a transmittingline having n section on each side of the repeater apparatus and inductively associated with the receiver-trunsmitter through said coil. the repeater-receiver being connected in circuit with the local .windings in a constantly maintained balanced relation whereby it is rendered insensitive to its own buttery currents but sensitive to the inducing currents from the line circuits and their associated secondary windings. the said secondary windings of the coil being divided between the line circuit sections, ihe'divisions in each cii= cult section being operative therewith individually io insure singlcncss of transmission effects and properdivision of current.

5. In :1 reciprocal telephone repeater system, the com bination of a inaimansmitting cil'cuii' divided at u repeater station into t o line circuit sections, terminal icle-' phones associated therewith to originate currents for reproduction. and a repeater apparatus comprising an electromagnetic telephone receiver and .a variable resistance transmitter associated in repeater relation to receive the telephonic currents from one of the circuit sections and to transmit facsimile currents of greater power to the associated circuit section and the terminal telephone apparatus therein, a repeating induction cell having plural secondary and local windings, said secondary windings being in the line circuits and divided between and appon i'ioned to the sections thereof, the repenter-receiver and transmitter both being connected ln'circuit with local windings of said induction coil and inductively ml clated thereby with the line sections to furnish the reproduced currents to each of said circuit sections simultaneously.

6. In a telephone repeater systemfthe combination of a' repeater receiver-transmltter, two line circuits, at repeat ing induction coll connected in the line and inductively joining the line circuits with both the repeater-receiver and transmitter, said repeating induction col] having a plurality of secondary windings divided between the two line circuits, and a plurality of local windings divided between the repeater-rece'iver and transmitter whereby they are in local relationship to the l jnecireuits, and both are in common inductive relationship with the secondary windings of said coil in the line circuits, and whereby each line circuit is supplied with the reproduced currents from the repea er by its individual secondary windings, and the repeater; :cciver is suppllethwith individual induced currents from eac line circuit.

7. In a telephone repeater system, the combination of av main telephone circuitcomprising two line circuit secreceiver and transmitter each being in circuit with sep araic local windings of the repeating induction coll, the

secondary windings being associated with ouch other and with the line as follows: a winding-for each circuit sec" lion on cach'side of the line, the windings being connected to each line coru'tuctor iiulividually at each side, the wind tags on each sidebavlng'their other terminals connected and the connected terminals coupled by a low resistance conductor, thus providing individual secondary windings for each line circuit section.

8. lo a telephone system for reproducing the initial currents with increased'powor for extending the distance of transmission directly, :1 through compound line circuit comprising two telephone line circuits terminating in a repeating apparatus at an intermediate repeater station, a repeating telephone consisting oi a receiver and a trailsmittcr associated in repeater relation and a repeating induction coil having plural secondary and plural local windings, a bridge of low resistance at: the repeater station connecting the two through line circuits :fnd terminating the line circuits; the secondary windings of said repeating induction coil being divided and apportioned to each line circuit.- bul said windings collectively being in operative relation with both the receiver and transmitter and receiving from and transmitting to the line circuits the telephonic impulses the repeater-receiver and transmitter being in circuit with the local windings of said coil and adapted to be actuated only by the currents in duced from each line circuit.

il. in a telephone repeater system, the combination oi a main line circuit, a repeater, said main line circuit being divided into two circuit sections at the repeater, local circuits tor the repeater receiver and lransmiii'er a rcpealing induction coil having secolulary and local wimi iugs. lilo second; v windings being a mortioucd'to two line circuit sections and the local windings apportioned to the local circuits, both said receiver and transmitter being in direct inductive relation to the secondary windings of said coil whereby said secondary windings serve in common for the inward and outward currents ol the repeater rc wielv and transmitter respectively, the secondary windings at each side being connected to their respective line conductors, and said windings on each side having their other terminals connected, and such connected terminals being coupled by a. condenser, forming a low resistance path for the teieplu'uiic currents to traverse between the main line circuit conductors.

bination of a. 11min telephone-circuiit, a ln'lligeconnection between the conductors thereof, a repeater apparatus comprising a receiving magnet and a variable resistance transmitter actuated thereby. a repeating induction coil interposed between said maincircuit and the sa id repeater apparatus, said repeating induction coil having a secondary 5 winding composed of four helices, each helix being wound over a separate section of a magnetic core, and'conneci'ed in the main telephone circuit so that two divisions of the wlnding w ill be on each side of said bridge connection. and eight local helices divided into two groups otfonr substan r tially equaldivisions and wound to correspond to thesaid secondary divisions, each section of ,the core thus having three helices; four local helices, one for each section of said corefa battery and transmitter circuit containing a bridge two helices being eounected'togcther on each side corresponding to the two secondary helices on each Side of said first named bridge, and eachpair connected together and to the last named bridge conductor by their remaining terminals, so that said bridge conductor, its battery, and

mary circuit to correspond to the divisions of the secondary circuit; a third bridge conductor containing said receiving magnet with which the four remaining local helices are similarly connected.

1]" In a telephone repeater system, a laminated iron ring core repeating induction and retardation coil, having four'electromagnetic sections, individual secondary and primary mutually inductive windings for each section} two secondary windings on each hall at the core across one sion with two terminals for connection to the',line, a.

bridge connected on each sidef to the Joined terminals of the two said halves, said bridge connection being made to form two halves of the coil across a diauieteralt right angles to the aforesaid diameter. of the core, the latter halves being composed of one coiloteacb of the former halves,

and tog ther constituting four overlapping secondary'ci r cults. adpted to be variously connected for inductive and non-inductive effects for single and simultaneous service. 12. In a telephone repeater system, a telephone repeater apparatus, comprising a repeater receiver and transmitter,

two main telephone circuits or circuit sections, a cord circuit joining them, saidiordectr'u it containing a repeating induction coil, divided secondary and local windings in each elrcult section when the cord circuit is in use, the

repeater receiver and transmitter being directly connected in circuit with the local windings of said repeating induction coil, and inductively associated with the secondary windings of said cell, and with nib main telephone circuits".

13. In a telephone repeater system comprising two sections of transmitting line. a Repeater apparatus and instrn=- ment circuits local to said llncnnd at an intermediate e a tion thereon, the combination of means within said local ctrreceiver. said means when operating as a balance being independent of the line to prevent the creation in the receiver of selfatction effects tending to disturb-the transmission and distort the-form ot the'orlginatlng currents,

initial telephonic currents in said main circuit from being transmitted directly beyond the repeater; a repeater apparntus'comprising a receiver and a transmitter in repeater relation, and a repeating induction coil, the secondary windings of which are in the'niain circuit sud the local' windings of which are in circuit with the said repeater apparatus.

.15. In a telephone repeater system, the combination of a main circuit and twomlocal circuits, each of which is divided to form separate circuits, a repeating induction 160 thevariable resistance transmitter, will divide this pri- 100 diameter being connected together for through transmis 110 said coilfn portion of said secondary windings being in 125 cults for establishing an electrical balance for the repeater said balancing means constituting-a part of suidinstrir being divided to form separate circuits to prevent the distorting currents, the

coil having its secondary windings divided between the divisions of themain circuit, and its local windings divided between'the divisions of the two local circuits, and

a telephone repeater apparatus directly associated with 5 the said local windings and inductively associated with the snidinain circuit secondary windings.

10. in a-telephone repeater stem. the combination of main and local circuits each divided to form separate circuits, a-coinpound induction coil for preventing reactive condary windings of which are divided in service between the sections of a main tale phone circuit. and the local windings of which are divided between the sections of the local circuits. a repeater apparatus associated with the local circuits. said coil being 5 the medium for both receiving; and retransmittin all the telephonic currents between said repeater apparatus and said main line. the repeater apparatus being connected in said local circuits in a constantly maintained balanced relation whereby it is rendered sensitive to the 0 received currents and inert to its own currents.

17. in a telephone repeater. a composite repeating induction and retardation coil having a plurality of secondary and local windings for transforming the telephone cur rents, .ich of said secondary winding-s being wound on a separate section of the core and connected in a compound metallic telephone circuit, the several secondary windings being, divided into conductively and inductively connected sections, the said sections being arranged to create overlapping magnetic fields and operative to create a conductive 0 differential condition in the coil for composite extra currents passing through on each side of the circuit, a bridging condenser connecting the conductively connected sections of the coil to form the inductively connected sections for the telephonic currents which terminate at the coil.

18. in a telephone repeater, the combination of an in ductlon coll o! ring core type, having four secondary wind lugs, each on a separate section of the core, two of which on either side are connected conductively but non-inductively together to form noiriiiductiive halves, -a condenser 0 joining, inductively said conductive halves to form two inductive halves. each oi which is composed of one coil of each of the conductive halves, and mutually inductive local windings similarly disposed on the same core for transformim: in connection with the secondary windings the 5 repeatertelephonic currents.

in. In a telephone repeater system. a telephone repeater apparatus including a local circuit in direct inductive assoiation with the line conductors of the mainline circuit, a bridge conductor dividing the local circuit, a battery and U a transmitter in circuit in the bridge conductor, and local windings in each side of the local circuit.

20. in a telcphorcrcprutcr apparatus, the combination with a local circuit. of a bridge conductor in said local cir- (2OIldllCt0i'.'l\ second local circuit, and a receiver in said second local circuit,

21. In a telephone repeater system, the combination oi a main line having two metallic circuit sections associated with a repeating induction coil, a telephone repeater re 0 ceiver-trnnsmitter ilrcircuit with the local windings of said induction coil and in direct inductive relation to the secondary windings oisaid coil, and said main line sections being in Circuit with the/secondary windings of said coil, the secondary wit'idincs being divided and apportioned to 5 said main line sections for respective individual operation therewith, .and auxiliaryconductors provided with inductanccs l' orml p shunts around the repeating coil .for the through transmission of slow-acting currents and for the protection of the repeater recciver-transmitlcr..

22. in a telephone repeater system. the combination of a main telephone circ it, the two conductors of which are separately and jointly adapted for the transmission of superposed currents. a telephone repeater station on said circuit, a bridge connection between the two conductors of 5 said circuitat' the repeater station, a repeater apparatus at said station comprising a receiving: magnet and a variable resistance transmitter actuated thereby, a composite rcpeuting induction anti retardation coil inductively associntlng said main circuit and said repeater apparatus, said coil having a. magnetic core. and primary or local and sec cult, a battery and transmitter in circuit in said bridge ondary windings, the secondary winding being divided into four helices each helix being wound over a separate section of the magnetic core and connected in said main telephone circuit so that two helices of the said secondary winding will be on each side of said bridge connection; two local circuits. one constituting: a tertiary circuit divided by a bridge conductor containing the receiving magnet, and the other constituting a primary circuit divided by a bridge conductor containing, the transmitter and a battery, each of said local circuits containing a division of said local winding, each division being divided into two groups, each group having four helices which are connected in pairs on each side of saidfbridge conductors, each group being wound to correspond in position to the helices of said secondary vvindin; each section of said magnetic core having three helices, and each section constituting a distinct inductive electromagnetic field; one helix from each of said divisions of said local winding forming one of said groups ot'hclices, one helix of which group being on each section of the core and connected in circuit with said battery, thus one .pair at helices on each side of the coil is in corresponding position to the two secondary helices on each side of said main circuit bridge connection, and the pairs beinr; connected to their local bridge conductor by their remaining terminals, so that the local circuit containing the battery and transmitter will be divided by its bridge conductor towel-respond to the said division and arrange-,

nicnt' oi the secondary circuit ot'ssaid coil, the other group of four local helices being connected in said tertiary circuit and arranged similarly to the first group; 'an auxiliary conductor containing an inductance connected around the said secondary windings to the line conductors on each side of the main circuit, and conductors containing conde'nscrs connected around said secondary windings tor shunting therefrom high frequency through superposed currents.

23. In a telephone repeater system, a, laminated iron ring coro repeating induction coll having four electromagnetic sections, individual secondary and primary mutually inductive windings for each section, two divided secondary windlngson each lialf of the core, across one diameter, being conductively joined together and having two terminals for connection to the line, said windings being adapted to he variously connected, it non-inductance bridge connected on either side to the inner or joined ends of the two said conductive halves'to form two halves inductively connected by a condenseracross asecond diamer ter of the ring core at right angles to the first mentioned diameter, said latter halves being composed otone coil of each 01' the conductive halves and both together constituting four overlapping secondary circuits.

:24. in a telephone repeater system, the combination of a main telephone circuit, the two conductors of which are separately and jointly adapted for the transmission of superposed currents, a telephonic repeater apparatusassociatcd with said circuit, a repeating induction coil induct ivcly connecting said main circuit and said repeater 11pparatus, the repeaterapparatus being connected in ctr-- cult withthe local windings of said repeating induction coil, the secondary windings of said coil being connected in the main vircuit with two windings in each conductor thereof, each two windings being in series relatidh but differentially connected, bridge containing a cotidenscr in terposed between the two main circuitconductors, and connected to said conductors between the two windings in each of said conductors, condensers included in each con-- ductor of the main circuit, shunting inductance-s connected in circuit around. the secondary windings of the coil on each side, and condensers connected around said secondary windings and inductances to shunt from the repeater high frequency through superposed currents. I

25. in a telephone repeater system, the combination of a main telephone circuit, the two conductors of which are jointly and separately adapted for the transmission of superposed currents, at telephonic repeater comprising a receiver and transmitter associated with sald'circuit, a re peatiucinduction coil in the main circuit inductively connecting said main circuit and said repeater apparatus, the

- repeater receiver and transmitter both being connected in circuit with the local windings of said repeating induction coil, and the secondary windings of said coil being connected in the in: in circuit with two windings in each conductor thereof, each two windings being in series rela tion' but diiferentially connected.

26. lo a telephone repeater system, the combination of a main telephone 'cuit, the two conductors oi which are separatl y and ointi v adapted for the transmission of superposed currents, a telephonic repeater apparatus comprising a receiver and transmitter associated with said circuit, a repeating induction coil in the main circuit inductively connecting said main circuit and said repeater apparatus. the repeater rcceiver-trausinitter both being connected in circuit with the local windings of said re peating induction coil, the secondary windings of said coil being connected in the main circuit with two windings in each conductor thereof, each two windings being in series relation but differentially connected, and a bridge containing a condenser interposedbetween the two main circuit conductors and connected to said conductors hetwecn the two windings in each oi said conductors L27. in a telephone repeater & stein, the :ombination of a main telephone circuit. the two conductors of which are separately and jointly adapted for the transmission of superposed currents, a telephonic repeater apparatus com prising a receiver and transmitter a soeiated with said circuit, a repeating induction coil in the main circuit inductively connecting said main circuit and said repeater apparatus, the repeater receiver-transinitter both being connected in circuit with the local windings of said repeating induction coil, the secondary windings oi said coil being connected in the main circuit with two windings in each conductor thereof, each two windings being in series relation but diilerentiailgconnectod, and a bridge conductor olf low resistance interposed between the two main circuit: conductors and connected to said conductors between the two windings in each of said conductors.

28. in a telephone repeater system, the combination of a main telephone circuit, the two conductors of which are separately and jointly adapted for the transmission of superposed currents. a telephonic repeater apparatus associated with said circuit. a. repeating induction coil indnctiveiy connecting said main circuit and said repeater apparuins, the repealcr apparatus being connected in circuit with the local windings at said icpeating induction coil, the secondary windings oi said coil being connected in the main circuit with two \viudino; in each conductor thereof, each two windings being in series relation, 2). bridge interposed between the two main circuit conductors and connected to said conductors between the two windings in each of said conductors, shunting iudueianccs connected in circuit around the secondary windings ot' the coil on each side, and condensers connected around said secondary windings and indtu anti-s to shunt from the repeater high frequency through suporposell currents.

Lll. in a telephone repeater sysle u, the combination of a mam telephone circuit, the two conductors thereof scpzr ratcljr and jointly adapted for the transmission oi superposrd currcnls. a telephonic repeater apparatus comprising a receiver and lransiuilier associated with said circuit a repeating lilrllu'lioii roll in the main (1 uit inductively courier-ting said main circuit and said rcpt-atelapparalus. ilurrpeatcr recoiver-transmitter both being connected in circuit will: the local windings of s id repeat inc; induction coil, the secondary windings o1 id coil a metallic cord-circuit, suitable plugs and jacks for connecting said cord-circuit between said main circuits at: Sdid station. an induction coil the secondary windings of which are in series eonncriioirin the conductors of the cort'i-circuit; a bridge connecting the two line conductors of said metallic cord-circuit, a local circuit. a local battery and a repeater appzniatus rompri 'ng' an electro-Inagnetic receiver and a variable-resisianco transmitter also at said station, both the repeater reccirer and transmitter and the local windings oi saidinduction coil being connected in the local circuits and in direct inductive associatitin with the line conductors of the main line circuit whereby they are operative to inward inducing currents from the main cireuit, but inoperative to the repeating local currents and the repeated or reproduced currents,

ill. In a telephone repeater stem, a cord circuit having appliances for connection between main telephone circuits atv a repeater station, an induction coil having" divided secondary and local windin associated with said cord circuit, the secondary wiudiu' s being in series connection in the cord circuit, a bridge connected to the two line conductors oi? said cord-circuit and between the divided secondary windings ol rid i1, circuits local to said serially connected secondary windings, a rcpeator-receiver in one oi aid local circuits and a rcpeatertrausuiiltor in another of said local circuits, said local circuits being in direct inductive association with the line conductors of, the main line circuit, and a local battery connected in the trans luitter local circuit with local windings of said coil, and the repeater receiver and transmitter being adapted to responsive repeater action to inducing inward currents from the main telephone circuit. and adapted to be irrcsponsive or inert to the r01 ting local currents, and to the repeated or reprot'iuccd currents sol up.

32. in a telephone repeater system, the combination of a main line circuit. a bridge dividing the circuit al a repeater station into two line circuit sections, a repeater station on said main line circuit, telephones at dis points on said line, circuit, said telephones or iuaiiug currents for reproduction at the repeater station. a re peatcr apparatus coiupriiug an clcclromaguclie telephone receiver and a variable-resistance telephone. tran mitter in repeater relation adapted to receive the said o Idling currents from one line circuit section and to reproduce for retransmission facsimile currents of increased power to the associated line rircuit suction and the telephone apparains therein, a repeating iuducliou coil iiuluclircly assocializig the line circuit. scrliops czuzb individually with both the repeater receiver and transmitter, llusecondary winding ol saidw'oil hating plural windings which are apportioned to the line circuit sections for individual and simultaneous operation. a cord circuit includin lid secondary windings, means associated with llu: rowlcirruil adapted for connecting, disconne ting and operating the Hill and repeater receiver and transmitter 1':ll'|l \vilh lhe said main line circuit, said ropcator l'llllY and trans miller cuch lacing in local circuit with primary windings ol the coil and the transmitter of said ropraliug' induction roll, a battery in circuit with primary windings ol' the coil and tho lrausiuiltcr, and local circuit means tor rendering the rcpetiler apparatus operative to the iuduciug currents from the line circuit sections liul. inoperative to its repro (lllt'ttl currents said rircuil moans also adapted to separatithe acti ns in the two circuit sections to prevent reinduccd rem-lion ciiects.

local NATHANIEL (i. \VAlt'llI.

\l'll bosses:

Bum). u l N i imucnn,