US628247A - Multiple telephony and telegraphy. - Google Patents

Description

Telcg-raphy, MetalliI "f Nb. 628,2471

t(N0 Model.)

` Patented July 4, |8994 M. HUTIN & M. LEBLANC.

MULTIPLE TELEPHONY AND TELEGBAPHY.

(Application led Dec. 30, 1897.)

5 Sheets-Sheet l.

ne mms rerum ro wma-1.1mm wnsnlnarn. n. c.

System'; Composite,

Teleg raphy, Metallic circuit.

No. 628,247. Patented luIy 4, |899.

M. HUTIN & M. LEBLANC. MULTIPLE TELEPHONY AND TELEGRAPHY.

(Application filed Dec. 30, 1897.)

5 sheets-smet 2.

(No Model.)

ms Param en. won fTuo.. msnmnmn, n c.

17s. TELEPHONY- l Syslems.4 Composite,

Telegraphy, Metallic circuit.

No. 628,247. Patented luly 4, |899. M. HUTIN &. M. LEBLANC. MULTIPLE TELEPHONY AND TELEGRAPHY.

(Appliention filed Dec. 30, 1897.)

(No Model.) 5 Sheets-Sheei 3.

gagne 61566.

me nonms "l-s m. summum@4 w smh-mm. u c

,A H xk e. S O D. ,m .0 NC O Hm D16 ma Ey TS a 7 Il' Teleg raphy, Metallc circuit.

No. 628,247.' Patented July 4, |899.

l M. HUTIN & M. LEBLANG.

MULTIPLE TELEPHONY AND TELEGBAPHY.

(Application led Dec. 30, 1697.)

I vaco/1g'- 5 Sheets-Sheet 4.

(No Model.)

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d7` TELEPHO N". DRAAFTSMAY Systems, Composite,

Tcslegraphy,y Metallic circuit.

NQ. 628,247. Patented July 4', :899.l

M. HuTm & M. LEBLANC.

MULTIPLE TELEPHONY AND TELEGRAPHY.

(Application filed Dec. 30, 1897.)

No Model.) 5 Sheets-Sheet 5.

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' UNITED STATES PATENT; OFFICE.

MAURICE I-lU'llN AND MAURICE LEBLANC, OF PARIS, FRANCE, ASSGNORS 'IO-THE SOCIT ANONYME POUR LA TRANSMISSION DE LA FORCE PAR LLEoTRrcIT, or SAME PLACE.

MULTIPLE TELEPHONY AND TELEGRAPHY.

AS1?'ECIFICA'IION forming part of Letters Patent No. 628,247, dated July 4, 1899. Application filed December 30, 1897. Serial No. 664,720. (No model.)

To @ZL wiz/0111, it may concern:

Be it known that we, MAURICE HUTIN and MAURICE LEBLANC, citizens of the Republic of France, and residents of Paris, France, have invented certain new and useful Improvements in Multiple Telephony and Telegraphy, of which the following is a specification.

Our invention relates to telephony and telegraphy, and comprises a method and apparo ratus of sending simultaneously over thesame line a number of telephonie or telegraphic messages, or both.

Our invention also comprises a new current-reinforoer by which we are enabled to i 5overcome and neutralize the resistance of a long line both in telegraphy and telephony and various other improvements to be hereinafter more specific-ally described and claimed.

2o In the drawings attached to this specification, Figure 1 is a general view of our improved system of telephony in a simple form. Fig. 2 is an elevation vof the commutatoi` or distributer and motor. Fig. 3 is an end View of the motor. Fig. l is a diagram of our improved system ot' telephony arranged in such la way that the telephonie cnrrents,.the synchronizingeni-rents, and the calling-currents may be simultaneously transmitted over the 3o same set of line-wires. Fig. 5 is a diagram of our system of multiplex telegraphy. Fig. 6 is a diagram of the preferred form of distributer, with connections, as applied to a system of telcgraphy or telephony. Fig. 7 is a view of our improved eurrent-reinforcer applied to a system of telephony. Fig. Sis a view of another form of the same. Fig. 9 is a View of one terminal station of a complete system arranged for transmitting simultaneously six 4o telephone-messages, six telegraph-messages, and' synchronizing-currents over a single pair of line-wires.

The arms 1 1', Fig. l, mounted on the shafts 2 2', (best shown in Fig. 4,) are supposed to be maintained inA synchronous rotation by the motors 3 3'. Each of these arms rotates about a six-part commutator or distributer 44' and serves to place the various segments of the distributor successively in connection with the line-wire 5 5. From each of the segments 5o of each of the distributers It 4' is carried a connection to a plug-terminal 6 6', while other plug-terminals 7 7' are connected to the ground-Wires 8 8'. -These ground-wires are connected to earth-plates 9 9', (shown in dot- 55 ted lines,) but may, if preferred, be joined by the return-wire 10 10. The tWo distributers are supposed to be located at different telephone central stations, in which case the plug-terminals 6 7 6 7 may be connected to 6o contacts-on the switchboard of the station. Ve have shown at one pair of `terminals at4 each station a pair of wires 11 12 11'. 12', leading to the subscribers stations, (indicated diagrammatically at 13 13' as compris- 65 ing each a telephone-receiver 14 14', an induction-coil 15 15', and a battery 16 16', with n a microphone-trasmitter 17 17' in the local primary circuit of the induction-coil.) The motors 3 3' may be constructed like ordi 7o nary rotary transformers and comprise each a field-magnet structure wound with coils 18 1S' and an armature 19 19'. The arma tures of these machines are wound like those nected, respectively, to commutatore 2O 20', on which bear brushes 2l 22 21' 22', supplied with'current from the direct-current genera tors 23 23'. The field-magnet coils 1S 18' are preferably excited in multiplewith the arma- 8o tures. Rheostats 24 2i are interposed in series with the direct-current sources 23 23', respectively. It will be seen that by theadj ustment of these rheostats it is possible to maintain the two motors in approximately 85 synchronous rotation. In order to render this rotation rigidly synchronous, we place on the shafts ofthe motors rings 25 26 25' 26', connected to diametrically opposite segments of the commutator, upon which rings bear the 9o brushes 27 28 27' 28', respectively. These latter brushes at one station are connected to the brushes at the other station through the line-wires 29 30. Fotthe circuit thus established the motors 3 3' act as generators of al- 95 ternati-ng currents operating to synchronize the rotation of the t'wo motors. If one of the motors tends to run in advance of the other,

of ordinary direct-current motors and conit will generate and furnish current to the other motor, tending to speed it up, While its own speed is thereby reduced. The alternating currents thus passing over the line 29 We call synchronizi11g-currents. It will be obvious that the wire 30 may be omitted an d an earth connection substituted, as indicated.

1 1', two at a time', for very brief intervals ofl time.

We have Verifiedexperimentally with referen'ce to such a s ystem, first, that this intermittentconnection does not prejvent the transmission of Vocal sounds when the interval of time between the successive contacts of the arms 11.' with any particular segment of the distributers 4 4' is notgreater than about one onehundredth of a second; second, that the passage of the brushes carried bythe arms l 1 from one segment to the other does not produce any parasitic sound in the telephone-receivers; third, that theintensit)` of the sounds transmitted diminishes very slightly with an increase in the number of stations simultaneously served and that with commercial telephonie apparatus placed in operative relation with a system thus constituted it is possible to exchange with the greatest facility at least live simultaneous conversations.

We have thus established the principle of a system of multiplex telephony which renders possible the utilization of existing linewires, switchboards` and other apparatus.

Figs. 2 and 3 show the practical construction ofthe comniutators and motors. In these gures 3is the motor, having its field-magnets excited by magnelizing-coils 13. The armature 19 is provided with acommutator 20, on which bear brushes 21 22, and with rings 25 26, on which bear brushes 27 28. In order .to assist in rendering the motors rigidly synchronous, weplace on the field-magnets, preferably at the polar extensions, a dax-screen 32, such as is described in our Patent No. 529,272, dated November 13,- 1894. As explained in the said patent, this linx-screen tendsgreatly to assist the maintenance ofsyn` chronism and to prevent violent oscillations or variations oflspeed. This motor drives the distrbuter 4, on which bears the brush l, corresponding tothe arm 1 in Fig. 1. Each segment of the distributer is connected to a ring 33 33, on which rings bear brushes 34 34, connected to the plug-terminals G 6. (Shown in Eig. 1.) The" shaft of the motor is supported on suitable bearings 35 35.

We find it preferable in practice to utilize the same 1ine-wires which transmit the telephonic currents to also carry the synchronizing-currents, which result We accomplish by the improved syst-em shown in Fig. 4. .'In this figure of the drawings 4 4' are the distributers, driven through the shafts2 2 by the motors` 3 3', as before. These motors are supplied with currents from the direct-current sources 23 23', here shown as storage batteries, and the regulating-rheostats 24 24'. .36 36 37 37' are the linefwires, extending' from one station to the other and connected at their ends, as shown, to each other and to the wires 38 38', so as to form a complete metallic circuit grounded at each end through the earth-plates 9 9'. Itis evident thata pair of line-wires thus connected may be the seat of two sets of currents, oneset passing in 4the closed circuit 3b 36' 37' 37 and the other set' passing from the-earth-plate 9 through the'j` wire 38, through 36 36' 37 37' in multiple, and to earth through the wire 38' and earth-plate 9'. We interpose in the conductor 36 36'the primary windings 39 39'and in the conductor 37 37' the other primary windings 40 40' of a pair of transformers and placein likeinductive relation to each pair of primaries 39 40 39' 40' a single secondary 41 and 4l', respectively, each connected at one end to one of the brushes 1 l', bearing on the distributers 4 4', and at the other end of the common returns 8 8', corres onding to the circles 8 8' in' Fig. l. We interpose in each of the six circuits leading from the brushes 34 34 34' 34',

bearing on the rings 33 33 33' 33'on the shafts of the dist-ributers, the terminals 6 6' 7' 7, which, as above explained, may be placed on the main switchboard of the station andconnected to the apparatus of any desired subscribers. The primaries 39 4U 39' 40' are so wound that theireii'ects upon the secondaries 41 41' or the effect of the secondaries 41 4l' upon them will be cumulative, so that current passing, for example, in the coil 41 will ind uce current which will flow by the path 39, 3H', 36', 37', 40', 40, v37, and 36 and generate in turn a corresponding current in the secondary 41', and vice versa. Ou the other hand, any current passing from the earthplate 9 through the wire 38 willdivide at the points 36 37 and will pass through the primaries 39 40 39' 40' in such a Way as to produce no effect whatever upon the -secondares 41 41'. This path may therefore be used for calling-current or for synchronizing-currents or for anyother purpose whatever. .The

.grounded line-circuit we place in inductive or conductive relation with the circuit including the rings 25 26 25' 26' of the motorgenerators 3 3', which furnish the synchro.

n izi ng-cu rren ts, and we are thus able to trans-4 mit simultaneously the telephonie and syn` chronizing currents over a single pair of cond uctors. In this particular gure of drawings the synchronizing-currents furnished by the motor-generators 3 3' are shown as being inductively transferred to the grounded linecircuit by the transformers 42 42'. We are thus enabled to use synchionizing-currents of high potential on the line, which is of ad vantage if the line has a high resistance. It

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will be noticed that any earth-currents tending to fiow in the circuit will also be divided, as are' the synchronizing-currents, between the primaries 39 40 39' 40' and will not affect the telephonie instrument. We thus obtain all the advantages of a complete metallic lcircuit as far as the telephonie interconnection is concerned. Another advantage of this arrangement is that it renders it possible to give a very high potential to the synchronizingcurrent without transmitting that voltage to the telephonie switchboard or to the subscribers stations. In'order that one of the central stations may be able to call the other, we place in the branch circuits 43 43' from the wires 38 38' the bells 44 44' and the callinggenerators 45 45', which may be-ot the A lldank Abdakanowitz type, well known in the art. In ord er to separate the callin g-currents from the synchronizing-currents and to force each to tlow in the proper branch, we render the branch circuits from the wires 3S 38', leading to the transformers 42 42' and to the bells 44 44', respectively, resonant, each to the frequency of the current which it is designed to carry, by the insertion therein of condensers or condensers and reaction coils, as'indicated at 46 47 48, thc. The action of a system thus constituted is as follows: Sup- 3o pose, for example, that one subscriber, as

13, wishes to communicate with another subscriber, as 13'. The subscriber calls in the usual way the central station to which he is connected and asks to be putin communication withg13'. The operator at this central station then calls the operator at the other central station by means of the callinggenerator 45. The current from this generator passes through the bell 44, the resona- 4o tor 47 4S, the wires 43 and 38, and divides,

flowing through the wires 36 36'and 37 37' in multiple without aiiecting the secondary 4l 41, and from 36' 37' passes through the'wires 38' and 43', through the resonator 47' 43', and through the bell 44', actuating this bell. From the bell the current returns through the generator 45' and the earth-plates 9' 9 to the generator 45. Having secured the attention of the operator at the second station, the

5o operator at the first station requests that the subscriber 13' be called in the usual way and plugged to whichever pair of terminals 6' 7' may happen to be free at that particular instant. At the same time the operator at the first station connects the subscriber 13 to the corresponding pair of terminals 6 7, as is clearly indicated in the drawings. These two subscribers are now in a condition to communicate with each other without interference 6o from or with other subscribers or with the synproper calling-currents, and all necessary synchronizing-currents simultaneously over the same pair of line conductors.

Although we prefer to maintain the comin utators or distributers in synchronous rotation by means of the apparatus above described, since this gives better results than any other method with which we are acquainted, it will be obvious that various other methods may be used with more or less success. Thus, for instance, the distributers at the two stations may be driven independently by clockwork or by synchronous tuning-forks and be corrected at intervals for differences of speed by synchronizing impulses, as is Well knownin the art; `but in that case the synchronizing impulses may by our system be sent over the same line which carries the telephonic and signaling currents simultaneously without disturbance of either by the others.

the telephonie apparatus hitherto described by telegraphic apparatus witho ut altering the operation of our invention; but the problem of multiplex telegraphy is in some respects simpler than the problem of multiplex telephony, particularlyfor the reason that in telegraph-work alternating currents are not necessarily employed. Fig. 5 shows one station of a sextuplex telegraph system arranged in accordance with our invention. In this figure 38 is the line-wire coming in from the distant station and leading to the distributer 49 through the brush 50. The distributer is driven by the motor 3, provided with a commutator 20 and supplied with current from the direct-current source 23 through the resistance 24, as in the systems above described. On the shaft 2 of the distributer 49 are placed a number ot rings 51 51, with brushes 52 52, similar to the rings 33 33 and brushes 34 34 in Fig. 4. From these rings wires lead to the telegraph-keys 53 53 and Sounders 54 54, and thence through the common return S to the telegraph-battery 55 and the earth-plate 9. A branch wire leads from the wire 33 through the condenser 46and self-induction coil 56, though the self-induction coil may be omitted when the self-induction of the motor is suiiiciently great, through the rings 25 26 of the motor-generator 3, and to earth at 9. The motor-generator 3 is in all respects similar to with direct current in any desired man ner, as explained above. The condenser 46 and selfinduction coil 56 form an electric resonator tuned to the frequency of thesynchronizingcurrents, which will prevent the passage of the telegraphic currents through the motorgenerator. In this arrangement we prefer to give to the synchronizing-currents a very high frequency in order that they may be eiectually prevented by the self-induction of the tel'egraphic apparatus from flowing through apparatus is placed. Where the transmissionline is very long and particularly where a large number ot' messages are to be transmitted over the same wire sim ultaueously, we

prefer to replace the Sounders 54 54 by sensi- It will also be obviousthat we may replacel those shown in Figs. 2 and 3 and is suppliedthe branch circuits in which the telegraphic IOO' IIO

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tive relays, 'as shown at 57, each acting simply t 'open and close the key 58 in a local circuit in which is placed a battery 59 and a sounder 60. -lVe omit in this figure the connections tothe switchboard, 85e., which will t-erable to multiply the number of segments, as shown in Fig. 6.

lu this figure, which represents the application-of a multiple-segment distributer to the system show'n'in Fig. 4, 36 37 are the line-wires, connected at one end to each other and to the ground-wire 3S. In these wires are interposed the primaries. 39 40, acting jointly on the secondary 41, as fully explained above. One end of the secondary 41 is connected to four brushes 1 1 1 1, bearing at equidistant points on the distributer 4. The various segments of this dis- .tributer are numbered 61ZL Glb 61d (ile (51.61b

61c 61d`61e, die. All of the segments numbered 61 are connected to the ring 33, on which bears the brush 34, and so on, and the various brushes 34a '34", the. are connected to plug-contacts 6, leading to the subscribers stations, while the plug-contacts 7 ,which form the` returns from the subscribers stations are connected, through the wire S, to the secondary 41. The operation of this dstributer as distinguished from that of the distributor shown in Figs. 1, 3, 4, ttc., is simply to render it possible to drive the apparatus at a lower speed and to reduce the resistance introduced by the rubbing contacts and also to reduce the variations of current d ue to any slight jarring of the brushes. In all other respects its operation is the same as that of the formsabove described.

We have stated above that it sometimes becomes advisable to relay the telegraphic.

currents. When the multiplexing is pushed beyonda certain limit, it also becomes advisable to relay or reinforce the telephonie currents, and we may use for this purpose the new and improved reinforcer forming part of our present invention. Referring to Fig. 7, in which the reinforcer is illustrated in connection with a simplex system of telephony, the line-wire 62 62', grounded at each end through the earth-plates 9 9', connects two telephone-stations, which stations consist, respectively, of the receivers 14 and 14 and the induction-coils 15 and 15', with microphone or other transmitters117 and 17 and batteries 16 and 16 interposed in the local circuits of the induction-coils, as usual. Our improved relay or current reinforcer (shown at63). consists of an armature (i4-of the directcurrent type connected to the commutator 65,` on which bear brushes 66. The field-magnet winding 67 of this reinforcer is connected in series with the brushes and with the line 6.2 62. The reinforcer, which obviously consists, as far as described., of an ordinary serieswound d ynamo-maehine of the direct-current type, is driven by any preferred source of power. by such a machine is known to beat all times proportional to the current flowing therethrough, supposing, of course, that theiron 'lhe electronotive force developed is properly laminated and sufficiently free from magnetichysteresis. Therefore the electromotive force of the reinforcer will be proportional to the current iiowing in the line, and the machine will act to strengthen 'the telephonie current and to increase the loudness of the sound. In order to neutralize the self-induction and the armature reaction of the reinforcer, we prefer to place on the fieldmagnets an additional neutralizing-winding 68, so designed and wound that the magnetomotive force which it generates is at all times exactly equal and opposite to the magnetomotive force of the armature. We have described and illustrated the preferred meehanical construction of such a machine in our pending application, Serial No. 664,719, -filed December 30, 1897. While obviously such a relay or reinforcer lnay be interposed in each one of the branch circuits shown in our multiplex system in which the telephonie apparat us is placed, it is preferable to use, as shown in Fig. 8, a single machine to reinforce all the currents flowing in the line. In this figure 36 36' 37 37' are the two'line-wires of the sys.- tem shown in Fig. 4, and 39 40 39' 40" are the primary windings leading to the distributors. The reinforcer. 63 consists of a series-wound direct-current dyn amo-electric machine with two windings on its armature, which windings are connected, respectively, to two commutators 65 65h, on which bear, respectively, the brushes 66 (36a 66" 66h. One of these commutators and one of the two equal series fieldwindings G7 67b is interposed in each of the line-wires 36 36' 37 37'. The field-.magnet windings are so arranged that the effect of the telephone-currents flowingin the complete metallic circuit 36 36' 37 37' will be cumula- IOO tive, while currents flowing in at 3S and. out i at 3S' will act differentially in such a Way as to produce no effect in the field-magnets. In the saine way the armature-windings are so disposed that the electromotive forces created by them will be such as to reinforce the current owiug in the path 36 36' 37 37', but-will not tend to 'cause any current to flow in the external circuit 38 3S. Ve may, if preferred, add to such a machine neutralizing-windings, such as are indicated in Fig. 7. y

As it has been shown that currents flowing in at 38 and out at38 in the system shown in Fig. 4 will have no eect whatever on the apparatus interposed in the circuits ef the' distributers 4 4", and as it has also been shown from the direct current or low-frequency rcversed current necessary for telegraphy, it follows that we'are able to use the same pairof line conductors both for multiplex telephony, 5 multiplex telegraphy, and synchronization.

One end of a system accomplishing such results is shown in Fig. 9. In this figure the line-wires 36 37, in which are introduced the primaries 39 40, are connected as in the syslxo tern shown in Fig. 4. From the secondary 41 a wire leads to the brush 1 of the distributer 4, and from the rings 33 33 wires lead to the plug-contacts 6 6. Other plug-contacts 7 7 are connected,`through the return-wire S, to

x5 the secondary 41. This'is obviously our system of multiplex telephony above described; but, if preferred, we mayintroduce in any of the subscribers circuits leading from the contacts 6 7 telephony relays. Such an arrangezo ment is shown connected to the plug-contacts 6 7. The relay 69 consists of a magnet connected in series with the subscribers line in operative relation with the diaphragm of a microphone 7 0. In series with the microphoneis placed a battery 71`and a telephone-receiver 72. One coil of an ilnductorium 15, whose other coil is in a local circuit with the battery 16 and the transmitter 17, is mounted in series with the relayGS; but this relay may-obviously be replaced by the current-reinforcer .63, (shown in Fig. 8,) in which case one reinforcer placed in circuit with the wires 36 37 will serve to increase the. sound of lall the telephonie receivers simultaneously, as described with reference to Fig. S. From the wire 3S, connected to the common point of the conductors 36 37, lead two 'branch circuits. The first passes through the tuningcondenser 4G, through the rings 25 26 on the 4o motor 3., through the self-induction coil 56, and to earth at t). The branch carries the synchronizing currents and is tuned therefor. The second branch passes to the brush of the distributor 49 and thence, by the 45 rings 51 51 and brushes 52 52, to the telegraphic apparatus 53 53 54 54 57, fully described above in connection with Fig. 5. The battery 55 is interposed in the return-wire 8 for the purpose above set forth.

5o As all the elements of this system have been described above, it is only necessary to here state-that each element performs its normal function without ai'ecting or impeding the normal functions of the other elements, it be- 5 5 ing understood that the self-induction of the telegraphic instruments is made so great as to prevent the passage of the synchronizing currents.

It will be obvious that a common return- 6o wire may be substituted for the earth connections 9 9' in all cases.

We do not limit ourselves to the specific forms herein shown and described, as it is obvious that they may be greatly varied with- 6 5 out departing from the spirit and scope of our invention; but

lV e claim as our invention and desire to se cure by Letters Patent- 1. ln a system of multiplex telephony or telegraphy the combination with a line-Wire, a distributer at each end thereof acting to connect the line intermittently and successively with a number of telegraphic or tele- -phonic instruu'lents, means for driving the distributers, and means for synchronizing the distributers, the said synchronizing means being controlled by current passing from the line at each end to ground, through a select- ,ive resonant branch.l

2. In a system of multiplex telegraphy a line, a distributer at each end of the line and a means for synchronizing the distributors, in resonant branches of the line, substantially as described.\

3. In a combined .system ot`V multiplex telephony and telegraphy, a complete metallic circuit consisting ot conductors connected together and grounded at each end, and affording two current-paths, one throughthe metallic circuit and one from earth to earth through the metallic circuit-conductors in multiple, a telephone or telegraph distributer at each end of the circuit, the distributers being connected together through one ofthe paths, and means for synchronizing the distributors by current passing through the other of said paths, substantially as described.

4. In a combined system ot' multiplextelephony and telegraphy, a complete metallic circuit consisting of conductors connected together' and grounded at each end, affording two current-paths', one through the metallic circuit and one from earthto earth through the conductors in multiple, a telephone-distributer at each end supplied with current through one of the said paths, a telegraphdistributer at cach end, supplied with cnr- 'rent through the other of said paths, and means for synchronizing the distributers by current passing through the conductors in such a way as not to aiect either the telephonie ortelegraphic apparatus.

5. The combination with two wires joined at cach end to each other and to the earth or other return, of four primary inductive windings, two in each wire, forming a pair for each end of the metallic circuit, and two secondaries, each in inductive relation to one pair of the inductive windings, a distributer in each secondary, and means for synchronizing the distributers, interposed in the ground or return wire, substantially as described.

6. The combination with a line composed of two wiresjoined together at each end and connected to the earth or other return, of four primary inductive windings, two in each wire, forming a pair for each end of the metallic circuit, and two secondaries each in inductive relation to one pair of primaries, a distributer in each secondary, a second distributer in a ground or return connection at each end of IOO IOS

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the line, and means lor synchronizing the dissaid motors, and connections whereby the two motorsv act as two alternating' current dy- .to each otherV and to earth, or to a common .Wilhafplurality of primary windings and a vcuits that acurrent iiowing from earth to earth will not affectthe secondaries, but that ary, and a distributer in each secondary circuit.

ai.' Metallic circuit.

tributers interposed in a ground or returnconnection. l

7. The combination with telephone central` stations, o'f a line connecting the same, adistribliter supplied with current from said line at each end, a continuous current motor for driving each distriburer, having,r connections between their armatures, whereby the same lnay operateas alte mating-current generators to synchronize each other, and connections from the distributers to terminals adapted to be connected to subscribers stations, other similar terminals, and connections from the last-named terminals to a common return.

8. The combination with a system of -multiplex telegraphy or telephony, of a pair of distributers, an electric motor of thedirectcurrent type for dri-ving each distributer, independent means 'for regulating,r the speed of name-electric machines in multiple, and tend to synchronize.

9. The combination of line-wires, con nected return, at each end, two transformers each common secondar ,the primaries of the transformers being so interposed in the line-ciran alternating current flowing,T in one secondary will produce current in the other second- 10. lIn a multiplex telephone system, a pair lvof enteringI line-wires, each including one primary coil of a transformer, a .secondary coilon the transformer, in cumulative induct ive relation to both of the primaries, a dis-- tributer in circuit with the secondary coil, and a common ground for both line-Wires through a device forcontrolling the rotation of the distributer, substantially as described. 11. In a multiplex telephone system, a pair of entering line-Wires; each including one primary coil of a transformer,a secondary coil on said transformer, in cumulative in ductive relation to -both of the'primaries, a distributer, supplying current to telephonie apparatus, in series with the secondaryl coil, and a common ground for both wires 'divided into two selective branches, one including means for synchronizing the distributer', and

the otherinclnding a callingdevice, substantially as described. 12. In a system of telephony, in which synchronizing and telephonie currents are carried by the same line conductors simultaneously, the combination ofa current-reinforcer on the line, consisting of a series-wound dynamo connected so as to be energized c xcle. sively by the telephonie currents and thereby selectively reinforcing the same, substantiallyas set forth.`

In testimony whereof We have signed our names to this specification in the presence of Y two subscribing witnesses.- MAURICE HUTIN. p MAURICE LEBLANC.y

YVitnesses': y

EDWARD P. MACLEAM, PAUL BoUR.

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