US810335A - Telephone party-line system. - Google Patents

Description

7 PATENTED JAN. 16 P. B. HALL & A. P. POOLE. TELEPHONE PARTY LINE SYSTEM.

APPLIOATION FILED SEPT. 23. 1901.

WITNESSES UNITEDCSTATES PATENT OFFICE.

FRANK- B. HALL AND ARTHUR nroonn'or WHEELINQ-WES VIRGINIA.

TELEPHONE PARTY-LINE SYSTEM.

Specification of Letters Patent.

Patented-Tan. 16, 1900 Application filed September. 23,1901. erial No. 76,154.

To all whontit may cncer n.- Be it known that we, FRANK B. HALL and ARTHUR F. P0oLE,of Wheeling, Ohio-county,

West Virginia, have invented a new and useful Party-Line System, of which the following "is a full, clear,. and exact description.

Qur invention relates to selective party'- line systems for telephonelines, and is de signed to overcome the 'disadvaritages incident to such systems as heretofore arranged.

These subscribersystems comprise two general classes. In the one class devices are employed at the stations which-respond to currents of dilierent strengths and polarity from the central'station- In this system a sent fromthe central station. This system necessarilylimited to a smallnumberof stations-oneach line and 'is faulty because of the 'delicacy'of adjustment required and the liability to get out of order. The other class comprises 'amechanically-o erated st'ep-by-step mechanism located at t esub- -stations and actuated by acommoi current' powerful current is necessary 'to operate all themechanisms simultaneously, as the stations usually are included in parallel relation. In our improved system only a small current is necessary to operate the selective devices, they being actuated se arately and- .3

successivel ."Thc system can e -applied to any partyine without any change 1n the orstatlon with a continuous line on oneslde' dinary telephone condition, and the mech-i anism at each station is aduplicate of that,

at all the others. The invention consists in connecting each and with a normally broken line on the other side. This system we consider, broadly, new, and it enables us to build up or comtern for locking out all other subscribers in' plete the broken line to any station desired,

and thus complete the circuit through such. station. The stations are normally 'connect-,

ed with the ground, and the invention further consists in providing automatic switch m'echanismat each station, which when actuated by a current sent over the broken line to ground will open the ground-circuit and connect the broken-circuit sections between the" several stations. to form a continuous metallic sidedline to the station de- Sired- -l 'The invention also consists in a new systhe party-'line'b the actof removing the receiver at'one o the stations.

The invention will be-inoreiully under/g wire F may be traced-through stood by rererrmg to the accompanying drawings, in Which F'gure- 1 is'a diagrammatic View of a partyline system constructed in accordance with our invention, and Fig. 2. is a detailed view of a lug and switch employed.

Li e characters of reference designate like parts throughout the. specification.

In Fig. 1 is illustrated a central station and four subscribin -stations A, B, G, and D connectedtherewit, although the number" of substations may be increased.' At each station is provided automatic switchin mechanism, which, as shown, consists 0 three electromagnets 2, 3, and 4, arranged in tandem; Armatures 5 and'fi are provided,

respectively, between ma nets 3 and 4 and.

2- and 3, said armatures being normally in the position shown in full lines. Each station is connected with a continuous line-wire F. and with a broken line-wire G. The magnet 4 serves to attract the armature 5 to its alternate position to disconnect the ground connection-at asubstation and to'establi'sh continuity of the broken line G.

The circuit through themagnet 4 may be traced'as follows: from the'wire G to the pivot 7 of armature 5,. to contactpoint 8,

through the ma net 2, through the magnet 4, to ground; V the armature thereof beingresponsive' to he magnet 2 is polarized,

only one direction of'current through the -magnet-winding. The circuit from the linethesubstation as follows: from the Wire to a point '21-, from whence two paths may be traced, one path leading to a point 20, to the primary winding 19 of an induction-coil, to transmit- I ter 18, switch-hook 17, contact 16, signalbell 15, contact-point l4, armature 6 when throughthis circuit magnet 4 becomes energized and responds to attract armature 5 to its alternate position, (shown in dotted lines,)

the'resultof this attraction being to open the ing contact 8 with the armature,

station. At the next portions of the lineG between substations ator 30. The'fstation-indicator consists of aareconneoted togetheruntil a complete -con tinuous line is established to the desired substation. p p

The equipment attire-central oifice con sists ofa signal controllin battery 24, 'a lamprelay 25, a lamp-26, a c caring-out drop 27, an operator's .circuit28, a station-indioator 29, a signaling-battery 57, and a generdial 60, a "pointer- 61, a ratchet wheel 62, mounted on the same shaft with'the pointer,

. a pawl 64, pivoted to an armature 65, said 1 to actuate the. ratchet-whee back by a s ring armature being adapted to I be attracted by an electromagnet 66. The

evil is disposed upon release of the armature, the armature being 'drawn' is connecte between binding-posts 32 and 33. Between binding posts 34 and 35 is placed the ordinary arrangement for supply ng talking which consist of -a""battery 68, impedance coils'69 for preventing the short-circuiting of voice-currents,

56,'to the tip and condensers for permitting ready transmission of voice currents.

'One side of the cordcircuit includes the clearin -out magnet 27, and when the plug is inserte in the ack the circuits to the linewires F andv G may be traced as follows: from one side of the battery 68 to binding post 34, to electromagnet 27,'to conducter 51 of the plug, to line F,throu h thesubstation apparatus to line G, to jac conductor 42, to ack-.th imble 36, theplugsleeve 53, conductor 55, binding-post 3 5, and

to the other side of the battery 68, talking,

- current being thus supplied to the substations. The operators circuit 28 may be bridged across the plug-circuit to enable the operator to supply current for the operators talking set.

The plug consists of a sleeve portion 53 and a tip portion 51, insulated from each other, a section of insulating material 52 intervening between the sleeve and the tip portions; This insulatin -section upon insertion of the plug in the jac serves to engage the end of spring 42 to disengage said spring from the contact 37. The clearing-out drop 27 consists of an electromagnet and an armature 38, acted upon by a retractile spring 39. Under normal conditions the armature 38 is at a sufiicient distance from the electromagnet to prevent attraction thereof by current flowing throu h the electromagnet, but will be retaine against the electromagnet upon being.

breaking of the circuit .t

e portion to the next sub station; magnet 4 is.

strands 55 and 56 of the cord circuit suppose that central wisl 'cating-electromagnet 66,

conductor 42', to

67. The electromagnet 66 'to armature 5, to contact 8, through electrocurrent to the transmitters,-

erases manually placed in such plpsition. Upon the ough said e1ectromagnet, however, the armature will be re leased'and pulled against the stop 40 by the retractilespring 39. The binding-post 32 of the indicator is connected to ground throu h a battery 57 and bindingspost 33 of the in icator, may be connected to the conductor 55 of the cordcircuit through a switch 43. The generator "39 may be bridged across time 3 means ofa-switch 45, one side of the generator connecting to, ground.

The: operation of the system is now appear-- ent. Starting with the line and apparatus in their normal condition, as shown in full lines, es to call station C. e-jack and presses She inserts herflplu 1n the following circuit:

the ke '43 to estab ish from t e negative side of'battery 57 to bind-- 0st 32 of the indicator, through the indito binding-post 33', through switch 43, to cord-strand 55, to the sleeve of thepl' to the test-thirnb le, jacke G, to armature-pivot 7,

magnets 2 and 4, to ground, and through the round-conductor at central to the positive side of battery 57. direction will not operate the olarized electroinagnet 2, but will energ ze magnet 4,

causing armature 5 to be moved to its alternateposition to enga tacts '23 and 9. As t tarily broken as armature 5 passes to ternate osition, the indicator-electromagnet 66. at the central station becomes momentarily deenergized to allow its armature to be attracted to revolve division-that is, to bring the pointer to position 1 on the indicator to show the operator that the connections at the first station have been successfully completed. Upon attraction of armature 5 at substation A the circuit through electromagnets 2 and 4 is broken, as also the ground connection, the

e the alternate concurrent from the line-wire G passing directly into the next section of the line-wire G, connectin station Awith station B, the same operation taking place at station B as has taken place at station A, and so on. Central now 0 ens the key 43 and closes switch 45, where y current from the signaling-generator 30 asses through substation C through the following circuit: from. generator 30 through switch 45, to cord-strand 55, to jackconductor 42, to line G, to contact 23 of station A, to line-Wire G, to contact 23 of station B, to line-wire G, to armature 5 at sta tion C, to contact 8, through magnets 2 and 4, to ground, and back conductor at central to generator 30. The current from generator 30 is alternating, and polarized electromagnet 2 will now be operated to attract armature 6, and armature 5 the ratchet-wheel 63 one,

Current flowing in this 1 ecircuit is momenits al-.

through the ground .55 substations with the exception of substation will also be attracted-to its alternate position; by electromagnet 4. The operatornow opens switch 45 and again closes switch 43 to bring the remaining armatures 5 on the line to their alternate position, whereupon -switch.43 .is', again opened. It will be'seen that there is now a complete metallic continuous lines between central and .the subscrib'erfs' signal-g ,in'g' apfparatus at substation ,Upon polo-q sure 0 switch 45 subscriber Omay now. be' signaled through the following circuit: fRorrP generator 30 through. switch 45, to 06rdstrand 55, plug-sleeve53, jaek-thirnble 36, jack-conductor 42, line-wire G, armature 5 and contact 23 at station A, armature 5 and I contact 23 at station B, to armature-pivot 7 at station C, to armature 6, contact 14, tsig- "nal-bell 15, contact 16, switch-hookfl7, transmitter 18, primary winding 19, to linewire F, to jack-spring 41, to plug-tip 51, cord- .strand 56, electromagnet 27, switch 45, and the other side of generator 30, This ci nit is entirely metallic, the grounds atall new substations having been removed bythd attraction of armatures 5 to their alternate; 0-

sition. Upon being thus signaled subscri r O removes the receiver irom the hook and; central connects .her talking-circuit to the line, the batte 3o 68 supplying current for both the subscri er and the operator, thecircuit hour the battery to-the subscriber after the-removal of the receiver from the hook be- ,ing 'traced as follows: from 5.ne side of the batter y 68 through the clearin' -o'u't electro- -magnet 27, through cord-fstranr 56, to jacks r1ng41, line-wire F, primary winding 19 of t e induction-'coil-at station 0, transmitter 18, switch hook 17, contact 11, contact 13, armature 6 line-wire. G, through contacts 23 anctarmatures' 5 at stations B and A, to jackconductor 42, cord-strand 55, and the other side of battery 68. All the other subscrib- 'ers on the line are prevented from listening-in on the line, as the armatures'fi at these other stations are out of engagement with the contaets 14 and 13, 'leadi'ng'to the substation signaling and-talking apparatus. Central havingascertained the party to whom the calling su scriber wishes to talk inserts the plug 72 in the 'ack of the called subscriber. Should the caliing subscriber desire'to talk to another subscriber- Whgi ,is party to the line to which he isconnected, he is notified byv central to press" the button 50, thus causing the break- .3 5 mg of thecircuit leading to substation C from the line -wire. F. Central now closes the -swit'ch 46 to connect battery 24 across the line-wires F and G. Electroma nets 3, which are bridged across the sides-oi the line,'are adapted to respond to current flowing from battery 24 to attract the armatures 5 to restore them to-their normal osition, whereby to break the continuity of t eline-wire G and Y to establish ground connections at each of the ta ily breaks the talking circuit 'as the.

spring 39 to restore the armature 38 to its them to their normal position, and the line is ;the alternating current from generator .30.

totheir normal C, which by res'sure of button has become discbnnected from the line.' Switch 46 is now open and switch 43 closed, whereby current from batter '57 is led' into, the ground and to line-Wire to select the party desired to be talked to by substation C, the circuits being the same as hereinbefore traced. After the subscribers have finishedtheir conversation the hanging up of the receivers momen- 7 switch-hookpasses from contact 16 to con-. 5 tact 11, and the clearing-out magnet 2-7, in cluded in the talkingscircuit, momentarily becomes deenergized, allowing the retractile normal position, thus indicating to the operator that conversation is ended},the operator upon such signal removing the plug from the jack. Theoperator now closes the switch. 46 to again apply current from battery 24 to the 5 line, and electromagnets 3, responsive to the current from said battery 24, attractithe armatures 6 and 5=at the substations to return 9 0 before outlined.

Asheretofore stated, the electromagnets '3 areiprovided with windings of high impedance an resistance, the impedance preventing I short-circuiting of-the talking-circuit. when 9 5 the magnet is connected across the limbs of the line and the highresistance preventing sufiicient energization of-the electromagnet by the talki'ngwurrent from the battery 68 or .100 The armatures 6 and 5 are only attracted by electromagnetfi when the battery 24 is d1- rect-ly connected across the line, the circuit through electromagnet 3 being traced as follows: from the positive side of the battery r05 24 through switch 46, to the line-wire F, to a point 21, through the electromagnet 3, to the alternate contact 9, to the armature 5-, to linewire G, through switch 46, and back to the negative side of the battery 24. Upon the no closure of the circuit just traced the electromagnets 3 become sufficiently energized to attract the armatures 5 and 6 to restore them osition. V

Tocall cent-ra it is only necessary for the 1 15 subscriber to remove the receiver from the switch-hook, whereupon the following circuit is established: f'romthe positive side of battery24, through relay 25, to the relay-armature 47, -to the spring-jack contact 37, to I20 jack-spring 41, to line-wire F, to the primary 19, to the transmitter 18, toswitch-hook 17, contact 11, contact 10, armature 5, contact 8,

the magnet 2, magnet 4, the ground, and

through the ground-conductor at central, to 1z 5 I the negative sideiof battery 24. Immediately on the'closure of this circuit the relay 25 becomesenergized and attracts the relar armature 47, whereby a local circuit is esta 1 lished, including the armature 47, signallamp 26, spring-jack contact 37, jack-spring battery 24, and relay 25, the lamp 26 be coming thus illuminated. Upon energiza-. tion of relay 25 the armature 47' becomes disengaged from the contact 48, thus breaking the contact of the battery 24 withthe linewire This is a very important feature, since it provides an absolute lockout'for all the other subscribers, and even if they should in take their receivers-from the hook to signal *central there would be nocurrent flowing through the substation to actuate the si n ing'device." Upon receiving the sigma the operator inse'rts' a plug in the spring- 'ack, whereby to disconnect contacts 37 "an 37 from the jack-conductor 42- and jack-spring 41, respectively, thus breaking the batterycircuit through the lamp 26, and the operator now proceeds to make the connections called for, as hereinbefore described.

The advantages of our invention will be obvious to those skilled in the art. The dithculties inherent in party-line systems heretofore devised are largely overcome, and man ofthe advantages of a separate line to eac station are obtained, and the system can easily be applied to existing party-lines with little expense.

We have shown and described the system 0 as applied to a so-called common-battery system, but do not wish to be limited tosuch application thereof, as it may be ap lied to a local-battery system with e ual adi antage; Many changes may also rea ily be made in 3 5 the apparatus and circuits employed without de arting from the spirit of the invention.

e claim as new, however, and desire to secure by Letters Patent I 1. In a selective party-line system, the 40 combination with a battery, -a continuous metallic line, normally open connections leading from said line to a series of stations, automatic switching mechanism at each station, and mechanism arranged to complete the circuit through said connection at any station v and then cut out the battery from the continuous line.

2. A central station having a. local signalcircuit, a continuous metallic line extending '50 from the-central station, connections leading from' said line to aseries ofstations, automatic switching mechanism at each station, mechanism arranged to complete the circuit at any station, a battery normally included in circuit with the continuous line, and meansadapted to cut out the battery from the continuous line and to connect it to alocal signalcircuit. r

3. A central station, a continuous metallic line extendin therefrom, a second line extending there 0m and broken at a series of stations, automatic switch mechanism for building up the Y broken line successively through each station, automatic switch mechanism at each station, including a polarized cuit at-each station, automatic switch mechanism for building up the broken line succes sively through eachstation, and automatic switch mechanism at each station, including a polarized magnet, and arranged to break the ground-circuit and connect the station to the metalliccircuit, and mechanism at central station for sending a reverse currentto actuate the polarized switch system at: any desired station; substantially as described.

5. In a tele hone system the combination with a central exchange, of lines extending 'therefromto a plurality of substations, telephonic apparatus at each substation, a polarized relay at each substation for controlling the corresponding telephonic apparatus, a non polarized relay at each substation for controlling the continuity therethrough of one of said lines, current-flow in one direction from the central exchange causing actuation of the non-polarized relays at the substations whereby the line controlled thereby'is made continuous to the desired substation, and means upon current-flow in another direction from the central exchange for causing the telephonic apparatus at the desired substation to be connected with the lines upon actuation of the polarized relay. v

6. In a tele hone system the combination with a centra exchange, of lines extending therefrom to a plurality of 1party-substations, signaling apparatus at eac substation, a polarized relay at each substation controlling the connection of saidsig'naling apparatus with the line, orie of said lines being normally broken at each substation, a non-polarized relay at each substation for controlling the continuity of the normally broken line, a source of current at the central exchange, current-flow fromsaid source through the lines in one direction causin successive actuation of the non-polarize substations whereby the normally broken line may be rendered continuous to a desired substation, means upon current-flow from said source through the lines in the opposite relays at the direction causing the actuation of the polarized relay at the desired substation whereby the signaling apparatus atsaid substation is connectedwith the lines, and-means at the central exchange for sendin signaling-current through the lines where y the signaling apparatus atthe desired substation may be selectively actuated.

7. Ina telephone system the combination with a central exchange, of

lines extending therefrom to a plurality of substations,- normally disconnected sections of line connect ing the successive substations, a rel a'y at each substation adapted upon actuation to close the line-sections terminating thereat, and means upon current impulse in one direction from the central exchange for causing actua-' tion of the successive relays at the substations whereb the disconnected sectionsmay be connecte together to offer a continuous line-to a desired substation, signaling appara- .tus at each substation normally disconnected from the lines, and a second relay at each substation controlling the connection of the 'sig- -naling apparatus with the line, current impulses from the central exchange in an oppostations.

- extending therefrom .to a plurality of partysite direction'caus'ing actuation of only the second relay at the desired substation where by the signaling-apparatus at this substation 15 connected with the central exchan e exclus ive of the si paling apparatus at ot er sub- 8, In a tele hone system the combination with a centra exchange, of telephone-lines,

substations, gone'of said linesbeing norma discontinuous at each substation,a relay at eachjsubstation for controlling thecontinuity apparatus at each substation, a second rela I forcontrolling the connection of said signa ing apparatus with the lines and with the thereat of the normally broken line, signaling central exchange',- means at the central ex: change for sendmgcurren't mpulse of one polarity into the lines and successivel serially through the two relays at each substas tion untilthe desired substation is reached,

= these current impulses causing the actuation of only the-first relays whereby said relays are disconnected from circuit and the normallybroken line rendered continuous to the desired substation, means at the central exchangefor sending impulses into the lines of opposite polarity torcause current-flow of op osite polarity serially through the two reays at the desired substation, the second-re;

, lay being responsive to this current-flow of Y opposite polarity wherebg the signaling apparatus: at the desired su station only is operatively connected with the lines.

I exchange, of 'telephone-lines' extending-therefrom to a plurality of partynon-'polari zed lines, a polara preceding sec-- vwith the lines, one of sai broken line and with the armature of the non-polarized relay, means at the cent'ral exchange for sending current impulses of onepolarity through'a normally broken line, whereby therelays at each substation are successively connected in, circuit,

said current-flow of one polarit causing ac- 'tuation only of the non-polarize relay where.- by the normally. broken'line is rendered continuous to the desired substation, means at the central exchange, when thede'sired substation is reached, for sending a current of opposite polarity over the built up -line, whereby both relays at the desired. substation are actuated and whereby the signaling apparatus at the, desired substation is connccted with the central exchange upon actuation of the polarized relay, and means at the central exchange-for sending a signalin -current through the-lines to actuate the se ected substation signaling. apparatus.

10..- I n a telephone system the combination with a central 'exc ange,.. of tele honeling; extending therefrom to a plura ity of party-substations, one of said l nes being normany-broken at eachisubstat on, a non-polarized rela on to close the normally broken y ateach substation adapted "uponactuati line thereat, signaling apparatusat each sub station norma y disconnected from the lines, a polarized relay at each substation controls ling theconnection of said si aling .apparams with the lines, said relays inginorm'all connected serially in circuit with t e prece ing section of-t'he normally broken line and with the armature of the non-polarized relay,

current impulse of one polarity through anorroc' means at the central e'xchangeior sending ma'llybroken line,whereby'the relays at each substation are successively connected in circuit, said current-flowiof one polarity causing actuation only ,of'* the non-polarized relay whereby the normally broken line is rendered continuous to the desired substation, means at-the central exchan e, 'whenthe desired .substation'is reached, or sending a current plolarity overthe' built-up l1ne,. t

of op osite where y bo relays at the desired substation are actuated and whereby the signaling apparatus at the desired substation is connected with the central exchange upon actui ation of the polarizedrelay, means at the central exchange for sending a signaling-current through the lines to actuate the selective substation signaling apparatus, and a'restoringrelay at each substation adapted upon actuaays and circu ts tion to restore the other re to their normal positions.

11. In a telephone system the combination with a' central exchange, of lines extend ing therefrom to a plurality of party-substathe connection of the si nali'ng apparatus lines being normally brokenat each substation, a second re- 1:? tions, signaling apparatusat each substation, a. relay 'at each substation controlling mall'y tion with a central exchange, of lines lay ateach substation adapted upon ,actuation to close the broken line;thereat,whereby the broken line may be rendered continuous to any desired. substation, a'restoring-relay at each substation adapted upon actuation to restore the switch mechanisms of the other relays to their normal positions. l 12. In a telephone system the combinaextending therefrom'to a plurality ofsubstatiens,

one of said lines being normally broken at each substation, a relay at each substation controlling thecontinuity of the normally broken line thereat, signalin apparatuslat each substation', a second .re ay controlling the connection-of said si naling ap aratus with the line, said first an second reiaysbeing connected serially in circuit, means upon current-flow in one direction from the central exchange into *the first-sectionot the norbroken line for causing current-flow. through the'first and second relays atthe first substation, meansfor allowing actuation of only the first relay, whereby the first section is directly connected with the following section leading to the second substation, whereby the normally broken line may -be rendered continuous to any desired substation, means at the central exchange for sendin current impulse of -o posite polarity through the built-u line an serially throu h the first and secon' relays at the desired su "station, said second relay being'i'esponsive to the connection of said si naling ap aratus with the line, said first ant second re ays being connected serially in circuit, means upon current-flow in one direction from the central exchange into the first section of the normally broken line for causing current-flow through the first and second relays at the first substation, means-for allowing actuation of only the first .rel'ay, whereby the first secthrough the builtup line ant serially throu tion is directly connected with the following section leading to the second substation, whereby, "the normally broken line may be rendered continuous to any desired substation, means at the central exchange for send-- ing current impulse of o posite polarity the first and second relays at the desired su station, said second relay being responsive to the current of opposite olarity,whereby the signaling apparatus att e desired substation exchange relay, actuation of t of saidsource.

is connected with the lines and with the central exchange, and a restoring-relay at each substation adapted upon actuation from the central exchange to restore the switch mechanisms of the first and. second relays to their normal-positions. v

' 14. In a telephone system the combination with a central exchange, of lines extending therefrom to a plurality of party-substations, telephonic apparatus at each substa-' tion, a source of current at the central'exchange, an indicator-relay at the central extus at any substation causing closure of a cir-' cuit through said source and said relay, actuatipn of said relay causing disconnection of said source from the line and connection of said source a local circuit including an indieatin '-signal. A v I 1 T 15. na telephone system the combinationwith a central exchange, of telephonelines extending therefrom to a pluralityof change, actuation of the telephonic appara I party-substations, telephonic apparatus at each substation normally disconnected. from the, line, .a relayat each sub stationcontrolwith the line, a source of current and indicating mechanismat the central exchange, actuation of the telephonic apparatus ata calling-substationcaming the closure of a-circuit through said relay, said source of currentland Saidsignaling apparatus, whereby the telephonic apparatus is connected in circuit by the relay, and means upon actuation of the indicating apparatus for causing disconnection of said source from the lines therebyto prevent connection ofthe telephonic apparatus with the line at other substations.

16, .Ina telephone system the c0mbina extend- -substasubstation with a central exchange, of lines ing therefrom to a plurality of part tions, telephonic apparatus at eac ling the action of said telephonic apparatus tion normally disconnected from circuit,-a relay at each substation controlling the co'nnec- I tion of said telephonic apparatus-with the lines, a source of current and a relay atthe central exchange, means upon actuation of the telephonic apparatus'at one substation for closing a circuit through said source of.

current to said substation-relay and centrale substationrelay causing connection of the telephonic.v

apparatus with the line and with the central exchange, and change relay causing disconnection thereby of said source from the line and connection of said source in a local circuit with an indicatlug-signal, the telephonic apparatus at other substations being prevented from connection with the lines upon disconnection therefrom '17; The combination with a central station, of a line running from said central station broken at a series of substations, electromagnetic mechanismcontrolled from the cenactuation of said central extral station adapted to build up a non-inductive circuit through said broken line to any "desired substation, a returncircuit from said substations to said central station, electric signaling apparatus at each of said substations, a second'line connecting all of said substations with the central station, and electromagnetic mechanism controlled from said central station adapted to connectthe saidsecond line with the signaling apparatus at anyof said substations, substantiallyas' described. v v -].8. The combination with a central sta-.

tion, of a line running. from said central stat1on broken at a series of substations, electromagnetic mechanism controlled from the cen-' tral station adapted to build up a non-inducti ive circuit through said broken line to any lines leading therefrom to a series of'substadesired substation, other electromagnetic mechanism controlled from said central stationadap'ted. to break said electric-circuit at said substations..a return-circuit from said substations to said'central station, electr'ic' signaling apparatus 'at each of said substations, a second line connecting all of said substations with' the central station, and electro--' magnetic. mechanism controlled from said central station adapted .to connect the said second line with 'the signaling apparatus at any of said substations, substantially as described. v

19. In combination, a central station, three tions, and electromagnetic selective apparatus at each of said substations adapted to be connected in series with one of saidlines, and adapted -to be connected in multiple with either of the other two lines,- substantially as described.

20. In combination, a central station, three lines leadingtherefrom to a series of substa- Y tions, one of said lines being normally broken at each substation, electromagnetic selective apparatus adapted to be connected in series with one of said lines and adapted to be con nected inmultiple with either of the other two lines, and electromagnetic mechanism adapted to automatically connect said selective apparatus in series with the broken line,

substantially as described.

21. In combination, acentral station, three lines leading therefrom to-a seriesoi substations, one of. said lines being normally broken .at each substation, electromagnetic. selective apparatus. at'eachof said substations adapted' to be connected in series with one of saidlines and adapted to be connected in multiple with either of the other two lines, and electromagnetic mechanism adapted" to. automatically connect said selective apparatus in series with the broken line and to automatically disconnect the multiple connection of said selective apparatus with one of the other two lines, substantially as described.

22. In combination, a central station,three lines leading therefrom to a series of substations, oneof said lines being normally broken. at eachsubstation, electromagnetic a paratus at each of said substations ada te to be connected in series with one of sai lines and adapted to be connected in multiple with 7 either of the other two lines, and electromagnetic mechanism controlled from the central station adapted to automatically connect said selective apparatus in series with the broken line, substantially as described.

23. In combination, a central station,three linesleadin'g therefrom to a series of'substations, one of saidlines being normally broken at each substation, electromagnetic selective apparatus at each of said substations ada ted to e connected in series with one' of said ines and ada ted to be connected inm'ultiple with either'o thejother two lines, andelectromagnetic mechanismat each of said-substations controlled from the central station adapted to automatically connect said selective apparatus in series with .the broken line, and to automatically disconnect the multiple connections of'said apparatus with one of the other two lines, substantially as described.

' 24. In combination, a central station,three I lines leading therefrom to a series of substations, one of said lines being normally broken at each substation, electromagnetic selective apparatus at each of said substations adapte\ to be'connected in series with one of said lines and adapted to be connected in multiple with either of the other two lines, and neutral electromagnetic mechanism adapted to automatically connect said sele'ctive'apparatus in series with the broken line, substantially as described.

said selective apparatus with one of the other two lines, substantially as described.

26. In combination, a central station,three lines leading therefrom to a series of substa tions, one of said lines being normally broken at each substation, electromagnetic selective apparatus at each of said substations adapte to be connected in series with each one of said lines and adapted to be connected in multiple with either of the other two lines,

and neutral electromagnetic mechanism con-' trolled from the central station adapted to automatically connect said selective a paratus in series with the broken line, su s antially as described.

27.- In combination, a central station,three lines leading therefrom to a series of substa-- tions, one of said lines being normally broken at each substation, electromagnetic selective apparatus at eachof said substations adapted to be connected in series with one of said lines and adapted to beconnected in multiple with either of the other two lines, and neutral electromagnetic mechanism controlled from the central station adapted to automatically connect said selective apparatus in series with the broken line and to automatically disconnect the multiple connections of said selective apparatus with one of the other two.

lines, substantially as described.

28. In a selective party-line telephone system, the combination with a series of substa- SUl)Sl-Liil ldlly as described. a

29. in a selective party-line telephone systions, electromagnetic selective apparatus at each of said substations, a connecting-line normally broken at each of said substations, a second line normally vconn'ectedto the selective apparatus at each of'said substations, a third line adapted to be connected in circuit with the selective, apparatus at each of said substations, and neutral electromagnetic mechanism adapted to automatically connect said selective apparatus in series with the broken line, means adapted to automat.- ically build up and restore said broken line and to break the normal connection with said second line and to connectsai'd selective apparatus in circuit with said third line, the selective z'tpparatus at any one substation being identical with that at all other substations,

tem, the combination with a series of substatrons, of electromagnetic selective apparatus at each of said substations, a connectingline normally broken at each of said sirbstatrons, a second line normally connected to the selective apparatus at each of the substations, a third lineadapted to be connected in circuit with the selective apparatus at each of the said substations, and electromagnetic means controlled from the centraLstation adapted to automatically build up and 're store said broken line and to break the nor'- mal connection with the said second line, and to connect said selective apparatus in circuit with saidthird line, the selective a iparatus at any one substation being idcntlcal with that at all other substations, substantially as described.

30. In a selective party-linetelephone s vs.

tem, the combination with a series of substations, of electromagnetic selectivejap 'mratus at each of said substations, a connectinglinenormally broken at said substations, a second line normally connected with the selective apparatus at each of said substations, a third line adapted to be connected in circuit with the selective apparatusat each'of said substations, and electroma 'netic means adapted to automaticallybufid up and restore said broken line and to break the normal connection with said second line and to connect said selective apparatus in' circuit withsaid third line, the selective apparatus at any one substation being identical with that at all other substations, substantially as described.

' 31. In a selective party-line telephone system, the combination with a series of substations, of suitable selective apparatus at each of said substations, a line connecting said substations normally broken at each of said substations, telephone instruments at each of said substations normally disconnected from said line, and means for connecting said telephone instruments in circuitwith said broken line, substantially as described.

32. ha selective'party-line telephone system, the combination with a series of substations, of suitable selective apparatus at each of said substations, a line adapted to connect said substations normally broken at each sub station, a second line normally connected to the selective apparatus at each of said sub-- stations, telephone instruments at each of said substations normally disconnected from said lines, and means for connecting said telephone instruments in circuit with said broken line, substantially as described. I

33. In a selectiveparty-line telephone system, the combination with a series of substations, of suitable selective apparatus at each of said substations, a line adapted to connect said substations but normally broken at each of said substations, asecond line ,normally connected with the selective apparatus at each of said substations, a third line adapted to be connected in multiple with the select- 'electric signaling apparatus at each of said substations, a second line connecting all of said substations with the central station, and

electromagnetic mechanism adapted to connect said signaling apparatus 111 clrcuit with two ofsaid lines, substantially as described.

35. The combination with a central station, of. a line. running from said central station broken at a series of substations, neutral electromagnetic mechanism controlled from the central station adapted to build up a non-inductive electrical path through said broken line to any desired substation, a return-circuitl from said substations to said ,v .with two .of

centralstation, electric signaling apparatus tric signaling tral electromagnetic mechanism controlled from the centralstation adapted to build upa non-inductive electricalpath through said broken Liane to any desired substation, elec-,-

tric signaling apparatus at each of said substations, a second line connecting'all of said.

substations-With the central station, and elec tromagneticmechanism'controlled from said station adapted toconnect saidsi centra naling apparatus in circuit W1th two of sa1d lines, substantially as described;

37. The combination with a central station, of a line running from said central station broken at a series of substations, electromagnetic mechanism c'ontrolledfrom the central station adapted to build up a non-inductive electricalpath through said broken line to any desired substation, a return-circuit from said substations to said central station,

. electric signaling apparatus at each of said tromagnetic mechanism controlled from the" substations, a second said substations with the centralstation, and electromagnetic mechanism controlled from said'central station adapted toconnect one a of said lineswith the signaling apparatus atany one of said substations, substantially as 'described.-

38. The combination with a central station, of a line running from said central 'station-broken at a series of substations' eleccentra station adapted to build up a non-in- .ductive electrical dpath-through said broken line-to any desire substation other electromagnetic mechanism controll central station adapted to break said electrical path at said substations, a return-cir- 7 cuit' from said substationsto said central station, electric signalingap aratus at each of said substations, a second e connecting all of said substations with the central statlon and electromagnetic mechanism controlled from the central station adapted to'connect one of'said lines with the signaling apparatus at any of said substations, substantially as described.

' ';39. The combination witha central station, of aline from said-central station broken at a series of substationsf' neutral electroma etic mechanism control ad from the centra station adapted to build up a noninductive circuit through said broken hne to any desired's'ubstation, a return-circuit from said substations to sa1d-central station, eleccentra line connecting all of.

ed from said apparatus at each of said substations, a secon line connecting all of said substations-with the troma netic mechanism controlled from said station adapted to connect. said si lnaling apparatus in circuit with two of sa1d mes.

40. The combination with a central station, of a linerunning from said central sta-l tion broken at' a series of substations, electromagnetic mechanism controlled from the centra station, adapted to build up a non-incentral station, and elecductive circuit through said broken line to any desired substation, other electromagnetic mechanism controlled from. said central station adapted to break said electric,

circuit'at' said substations, a'returncircuit from sa d substations to said central station,

electric signaling'apparatus at each of said substations, a second line connecting all of said substations with the central station, and electromagnetic mechanism. controlled from said central station adapted to connect saidsignaling'apiaratus in circuit with two of said lines, su s'tantially as described.- 4

41. The combination with a central station, of a line running from-said central station broken at a series 'of substations, electroma netic mechanism controlled from the centia station adapted to build up a non-inductive circuit through said broken line to any desired substation, other electromagnetic mechanism controlled from said central station adapted to break said electric circuit at said substations, a'return-circuit from said substations to saidcentral station, electric signaling apparatus at each of said substations, a second line connecting all of said substations with the central station, electromagnetic-mechanism at each of said substa tions' controlled from said central station adapted to connect said. signaling apparatus in circuit with two of said lines, substantially asdescribed. v i I 42: The eombinationwith a central station, of a line running from the said central StiltlOIl' broken at a series of substations, automatic mechamsm adapted to' buildup saidbroken line, a return-circuit from said substa- I -tions1 to said central station, electric signaling ap aratus at each ofsaid substations, a secon line connecting all/of said substations with the central station, and mechanism adapted to connect said signaling apparatus in a non-inductive circuit with two of said 'lines, substantially as described.

43. The combination with a central station of a l1ne running from said central sta} tion broken at a series of substations, electromagnetic mechanism adapted to'build up a-non-mductive electrical path through said broken line, retiirn-circuits from said substations to said central station, electricsignaling apparatus at each of-sa1d substations,- a second lme connecting all of saidsubstations described.

44. The combination with a central'station, of a line running from saidcentral station broken at a series of substations, electroma netic mechanism controlled from the centra station adapted to build up a non-inductive electrical ath through said broken line to any desired substation, a return-circuit from said substations to said centralstation, electric signaling apparatus at each of said substations, a second line connecting all of said substations with the central station,

and electromagnetic mechanism controlled from the central station adapted to connect 5 said signaling apparatus in a non-inductive circuit with two of said lines, substantially I as described.

45. The combination with a central station, of a line running from said central station broken at a series of substations, electroma netic mechanism controlled from the Y central station adapted to build up a non-induct'ive electrical path through said broken line to any desired substation, electric signaling apparatus at each of said substations, a second line connecting allof said substations with the central station, and electromagnetic mechanism controlled from said central station adapted to connect said signaling apparatus in a non-inductive circuit with two of said lines, substantially as described.

In testimony'whereof we-have hereunto

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