US1890480A - Telephone system - Google Patents

Description

1 3, 1932. B, w cg 1,890,480

TELEPHONE SYSTEM 3 Filed Feb. 24, 1950 Patented Dec. 13, 1932 uNiT S ATES A. LLACE, or CHICAGO, rumors, ASSIGNOR T KELLO G swnrcHBoARnAnn SUP-ELY COM ANY; on onioaeo, IIJZLIINOIS, A CORIBORATION oi'iLLIivoIsY T TELEBHQNE sYsgiEM 'a i a on fi d repr rjag, 1930. Serial No. 430,607.

inventionrelates to A a telephone eifecting communication between SubsCIlbe1S?;

linesby'ineans of a manual or semi-automatil y" p ai d, connect ng circuit, a d. pte W used. n x han es hlQh a e "connect both magneto and co nnionbattery subscribers lines. "The object of the invention is" to provide an improved system of the ab vecharact er adapted to completefcon -f nections either between subscribers having common battery type substations or between two subscribersone of whom has a common battery type substation. andthe other a mag;

neto type substation.

A feature of invention is a double disconnect cord in which certain of the same between a common battery and magneto necting disconnecting the operators listeningkcys to the line, the latter operation being. performed at the moment when the connection between the two substations has beeni con pleted thus providing for secret service.

.. Still another feature of my invention relatingtothe circuit as between a common battery and a magneto type substat ion isthe' provision whereby in the course of the dis connect and the recall operations the supervisory and the line lamps pert'ainingtoboth lines are put under. the control of the com nionbattery subscriber so as to keep the operator properly informed.

be more clearly pointed out in the ensuing specification appended claims. or a better un derstanding of the same reference may be had to the accompanying drawing in "which I have illustrateda preferred gin? bodi nent (r invention.

In th earer o e raw n a e. shown. a cord circuit (3 designed to eifect commu ni cation either from" a common battery 'substa{ tioIrA, shown to; the, left of the cord C, to

wa 9th r new Sub tati A,

shown'to the right of the cord C, or from a commonbattery type substation such as A shownalso to the right of the cord circuit.

Each of the substations A and A is connected to a respective line circuit LC or LC at the central of fice by a respective pair of lines 1, 2 and'lf, connected in multiple to a numberof jacks J and J 'which appear at a number of operators positions. Similarly the substation M is connected to its line cir cuit LO by lines 1 and 2 communicating withniultiple jacks J Each of the substations referred to is provided with a line relay LB, LB or L'R adapted to close the cirto a inagnet'o type substation such as .M

cuitfor a number of lamps L, L and L re I spectively. This is the usual "system employed to enable a plur lity of operators to be notified of the incoming call. Cutoff relays CO, CO. and'COare alsoprovided which, when actuated will deenergize the line relays LR, L11 and LE respectively. The cord circuit C is provided with an an swering plug AP, a calling. plug GP, and a four-pa'rty ringing keyPK, the latter being associated with the ringing generators G G5, Gfjand G vhich provide harmonic ring- 'ing current,jwhile,the generator G is for the purpose .of providing a revertive ringing toner An interrupter I intermittently cone nects the ringing current to'the'calledsub- IR. A repeating composed of four windings P1, P31? and P separated respectively. by two'condens ers D and D? is provided for the usual purpose. The above features, as well as others, will scribers line byalte'rnately closing and oplen- At the bottom of the drawing I have shown a circu't is established for the line relay LR",

traced from battery through relay LR. closed 7 contact 7 of cut-off relay CO,'line1, induction coil 8; closed switchhfook contacts 4,

WVhen the subscriber atuthe substation 'A'removes his receiver 5ffrfoin'the switchhook 6,

transmitter 9, line 2, normal contact 10 of relay CO to ground. Relay LR upon energizring attracts its armature ll'to complete a circuit for the line lamps L, traced from the battery through, the lamps L and closed contact 11 to'ground. The lamps L,;which are located at different operators positions are a lighted to indicate that a subscriber'is calling. One of theioperators will now insert an answering 'plug'su'ch: a'sthe plug AP of the cord C illustrated into'one of the jacks \Vhen the plug AP is inserted into the jack J, a circuit is completed for the cut-off relay CO which can be traced-from its grounded winding through the sleeve .contacts of the jack J and answeringplugAP, conductor 13,

tap 19, conductor 1 4, contact 18 of relay OCO,conductor 15, thewinding of the answering sleeve relay AS to battery thereby causing said relay AS toenergize. also. The control relay CR which is inmultiple on the same line does not'operate atthisvtime because ofits hi hresistancefwhioh isput in forthe purposeot not permitting the eneri gization ofany other operatorsset, should the latter try to connecther answering plug toflthe line after the operator at O has insertedhers." Relay COthereupon attracts its armatures 7 and 1O breaking the circuit for relay LR whose armature 11. returning to normal extinguishes the lamps L. The energization of relay AS as stated above, and closure of its alternate contacts, besides con- '-ne cting the terminals ofthe answering plug AP'to the line at cont-acts 20 and 29, causes also the en-ergization of the answering battery relay AB over a circuit which can be traced from battery through onewinding of said relay, through the winding P talking conductor 16, Closed contact 20 of relay AS,

' talking conductor 17, ring contacts of anl swerin'g plugjAP and jack J ,line 1, induction coil 8, upper cont'a'ct 4 of switchhook 6, l1ne 2, tip contacts of jack'J and answering plug battery B of the calling sleeve relay GS, normal contact 63, conductor 47, normal cont-act of relay OCO; conductor 51, closed contact 52 of relay AB, conductor 53, spring contact 54, peg cam relay PC, conductors and 34, normal contact 35 of relay O'CO, conductor 3'6, alternate contact 29,'conductor 22,

--coil P, relay AB to ground; The peg cam meter relay registers one count in the meter. I 653' relay-PC now looks up through its contact 54 v and completes a circuit for the meter relay 'M from the battery of the latter to ground. at alternate contact 54? of PC. By locking the The energizingof AS also connects the op- By closing their contacts the relays AB and 'relay OCO to ground;

erators set 0 to the line by a circuit which 7 can be traced fromthe lower contact 200i" AS, conductor 23, normal contact 24 ofrelay' OCO, conductor 25, condu'ctor 26 of the 'op erators set 0, condenser 27, conductors 28" and 29, operator head-set HS, conductor 31,

induction coil OI, conductors 32, 3 3, 34, coni to the line tact 350i? relay OC G, conductor 3.6 at closed contact29 of.relay AS; I v

The operator now talks 'togA and'learns of his Wish to talk to substation A, T hereupon she makes abusy test by touching the tip contact of plug GP to the sleeve contactof ljack 'J. If the latter isalready energizedby another operators cord, the first operatorwill phones due to the "energizationof the busy v receivethe characteristic cl1ck n herhead test relay BTR'I This energization is dueto the current flowing from anotheroperators V y 785 'nates in a battery simllar to battery Bassocord circuit, more exactly this current origi- .ciated 'with the control relay CR, which, as

can be readily seen communicates withthe sleeve contact ofplug AB. The correspondmg circuit can be-traced fromlone jack'J over lay IR, conductor '39, normal contact 40 of rBe lla ()CO, conductor '41'and busy test relay, it closes its contact thus completing a circuit to ground. The latter relay energizing from the battery 6 across the retard 'coils 42 b0 heavy conductor 37, springcontact 38 or reand 43, conductor 44, and induction coil and ground. The passage of current in the induc-I tioncoil 45 will cause theusual click inthe ope'rators head-phones in the usual manner.

7 If the party line A; is idle, the operator inserts the calling, plug OP into the jack J withthe result that the calling'sleeve relay CSand themarg-inal relays MS and MSare energized. The energizing circuit for the relays MS and CS can be. traced from bat-v f tery B of relayCR, normal contact 115, over conductors 57 and 58, relay MS,"conoluctor 59, relay CS, conductor 60, sleeve contacts of;

plug CP and jack J, relayv GO to ground.

7 The operation ofrelay MS causesthe energi-' zation ofthe auXiliarymarginal relayMS,

by current flowingfrom battery, winding of MS, over concluctor 61 contact 62 of relay MS.

to ground at closed As aresult of relay CS closing its contacts. the operators cut-off relay OCOis energized, I

the energizing circuit leading from battery B'ofCS, over alternate contact 63, lead 117,

Relay OCO, attracts itsgarmature and by opening contacts 24 and 35 associated with 7 leads 25 and'34 disconnects the operatorsset 0 from the line thus providing for secret serv- 1 ice. H The opening of a Contact 35 also inter rupts the circuit energizing the peg cam relay PC, as previously traced, restoring the same as well as the meter relay Mto normal.

The closing of relay MS completes'a' circuit for the calling 'supervisorylamp CL" tracedtfrom the battery B of relay CS,alt ernate contact, 63, conductor; 64, normalcontact 66 of; ringing disconnectjrelay RDR, conduc tor 6,7, closed contact 680i relay MS, conductor 69, normal contact 7 0 of relay IR, conductors 71 and 72-, normal contact 73 of relay RR,1anip CL to ground.

The operator next presses the proper ternate contact 63, conductor 64, normal con tact 66 of relay RDR,'c0nductors 67 and79, end spring ES, conductor 80, relay IE, to ground. After the end springs ES return to normal the'relay IR locks up over abranch circuit traced from the grounded winding of said relay over conductor 80, tap 81', conductor-8 3, alternate contact 84 of relay MS, conductor 85, alternate-contact of relay IR, conductor 69, closed contact 68 of relay *MS, conductor 67, contacts 66 and 63 of relays RDR and CS to battery B.

The locking of the interrupter relay IR completes a circuit for the ringing relay RR traced from the battery B. of relay CS, alternate contact 63, conductors 64 and 87 ringingrelay RR, conductor 86, normal end springs ES, conductor 85, and closed contact '82 to the interrupter I and its ground.

Relay BB is operated intermittently there by connecting ringing currentto the signal bell of substation A, from "the selected generator G through a circuit which may be traced on the cord side from the tip contact of the'calling plug GP, heavy conductor 87, closed contact 38, of relay IR, conductor 88, alternate contact 90 of relay RR, conductor 89, key 7 5, generator G generator common ground G1", conductor 95, alternate contact 94 of relay RR, conductor 93, closed contact 92 of relay IR, heavy conductor 195 to the ring contact of plug GP. On the line side the circuit can be completed fromthe tip vcontact of the calling plug GP over line 1 condenser C, closed contacts 4 of switch hook 6", call bell Cb, line 2, to the ring contact of the calling plugCP. Each time the ringing relay RE is energized to transmit ringing current to the called line the calling subscriber receives an audible ringing tone,

over a circuit which can be traced from, the revertive ringing tone generator G, through,

retard coil..30, condenser 111, conductor 74, alternate contact 65 of relay RR, conductors and 22, alternate contact 29, conductor 2land plugAP from whereitis transmitted to the receiver'at Am the usual manner,

If here is. no r sp nse fr m; A the subscriber at A abandons the-call and replaces the receiver, by doing so be breaksthe ener gizing circuit of relay AB, which deenergi ze's and opens its contact 12' which has-taken the place of contact. 18, now open,-but formerly: in the energizingcircuit of relay causes, the release also, of relay AS. By thesa-nie aft action relay, AB; causesthe energizationof;

the; control relay C3,,eurre1 t flowing; f iQnl batt ry B, h Winding of: r l y G ,I Qr el= contact 12 ofrelay AB,conductor- 1 3, sleeve contact of plug AP, relay COv to groundi By opening, its'lower contactrelay, GR "dis-; connects its battery B; from the'energizing i s e ays MSiand' G h ch res ore o n rm l releasing] at t e -m ti t eth relays: MS,IRa11d RRWhose circuits they control. The ringingthere-forestops and the" operator noticing the flash of the lamp AL,;

which had, been lighted bythe relay CR1 closing its alternate contact 115,[knows,;that the subscriberhas abandoned and; withdraws theplugstwhich brings the cord-circuit tov normal as subsequently described. However-it v the call isnot abandoned by Abut in answer to the signal the subscriberiat A removes his receiver 5 fromthe switchhook' a circuit is established for-the ringing disconnect, relay" RDR whichcan be traced from the battery and winding of said relay, over conductor 96,

ductor 195, ring contacts of: thecalling-plugx GP and jack J, line 2, 'switchhook. 6, in-,

duotion coil 8, line 1, tip contacts of jack Jf-and calling plug GP, heavy conductor 37, V

alternate contact 38, conductor. 88, normal contactv 90 0f relay'RR, conductor 99, closed,

vcontact 100 of relay'1MS,conductor 101 and relay RDR to groundf If" the subscriber answers during a ringing period .noaction, will take place due to the energizationiofi the 1 ringingrelay RR;as soon,as.the relay RR" restores"- its contacts 90 and 94 tonormal the; circuit for RDR is established. Upon enere gization relay RDR opens its contact-66 which as previouslyindicated forms a: link in: the energizing circuit of relay IR. The latter relay releases thereby deenergizing relay RR by breaking alternate contact/Z0 of'the energ zing circuit of the former and contact 82 of that of the latter. The ringing stops and the spring contacts 38 and 92 or relay IR, having returnedto normal, the "sub scribers are now able to converse, overthe heavily outlined conductors and through the repeating ooils,a ll intermediatecontacts bc. 1 ing closed, Anotherresult of the en rgi tion oiflrela y RDRis the clbsingof its-contact, 114 wh'lchconnects battery B in. parallel,

7 l ciated with'relay RDR; I

with battery B" of any on to" the holding I tact 63 of relay CS to battery B; Atthe' i eircuitof relay MS-andCS' Secret service is provided by the. fact that the'op'eratorsconnections to the line leading I 1;? from; the, c listening key LK over conductors 1O2'and 103, contacts 104 and 105 of relay M'S'and conductors 1 06 and 107 to the line have been broken by the energizationt 7- 1 y S/ J 1 v I 3* Assuming that thelconversation has beenc finished and thatthe subscriber at A is the first to replace his receiver, the latter action will cause the energizing circuit of relay AB m to be broken atthe switchhook 6.1 Relay AB 1 restores, to normal causing the release of relays AS and CO whoseenergizing circuits -origina'lly controlled by contact 18 of relay OCO have been transferred to contact 12 of s m relay AB after the energizationfof these two u, 2i) relays, With its release relay AS opens its contacts'20 and 29 associated with the tip "and ring contacts ofthe answering plug AP thus disconnecting thefsubscribersvfroin each other. Relay-CO releasing puts relay'LR in a 3i) of relay CO the corresponding portion of the circuit being the same as traced for the energization'of said last relay, which is not energized at this time because ofthe high resistance of relay CR. The energization ofrelay CR and the closure of its'alternate con= tactl115 causesthe'lighting of the answering V supervisory lamp AL, indicating that the 1 subscriber at A has replaced his receiver; and,

V through conductor 116, it connects the bat 46' tery B ofrelay CR to the energizing circuit of relayOCO, so that relay 060 will stay" energized when relay CS releases anddisconnects its battery'B from the energizing circuit of relay 000. A still further result 1 ofrelay CR closing its contact115 is the disc connection of'the battery B from the holding circuitof. relays MS and CS, leaving said relays under the control of battery B? asso- When the subscriber at substation A. replaceshis receiver the'circuit for relay BDR which as previously shown is controlled by the,,eontac-ts of switchhook 6,vis' broken thus opening contactsvll land 66." The first I of these disconnects the battery B from the energizing circuit of relays CS, MS and CO I which thereupon return toinormal causing also the relayj MS, which as has been india cated is lco nt-rolled by relay MS, tovreturn to 7 '69- normal, The release of relays MS and CS completes a circuit for the calling supervisory lamp jCL which can be traced from the lamp and its ground through "contact '73 of relay RR, conductors 7 2 and 71, normal con tacts 84 and 112 of relay MS, conductor 118,

readiness to flash' the lamp 'L' in case of recall.

fthe'battery B of relay CS over a portion of the circuit as just traced for lamp CL; conucomitantly relay CO having returnedto a normal, as above stated, puts the relay LR in readiness to flash. the lampfL in case of a.

recall by thesu'bscriber atA.

When the operator notices that both supervisory lamps are-glowing, she knows that the" conversationisterminated and removes the -5 plugs from'the jacks as resultof which-the V circuit as trace'dfor relay GR is broken at jack J, and said relayreturnsto normal opening its alternate contact 115, thu's extinguishing lamp AL and releasing relay 000. The

release ofrelay' OCO inturn causes the release of relay IRby opening alternatecon-- tact 50' forming a link'in .thelenergizin'g' circuit of said last relay as previously'traced.

ll the elements of cord C to normal. V If atterthe completion of a calland before the plugs have beenwithdrawnfrom'sthei-r; respective ackets the subscriber at A wishes to make a recall he will removehis receiver" I conductors "102 and 103,.closed contacts 104L- 9 a and 105 'ofrelay MS and conductors 106 and 107 which permits the operator to converse.

with the subscriber. ..Upon learning his de-l sire she will again actuate the proper ringing key PK. and upon the subscriber at Al re-Y 105 moving his receiver theoperation of the cord circuit will be reenacted as previously de-- scribed. r If after the completion of the conversation the subscriber at A has replaced his receiver while the subscriber at A has. not, the sub- 1 scriber at A can still resume the conversation because the line is held in readiness by. the battery B associated with 'relay 'RDR and the relaysCS, MSand MS controlled 5 bysaid relayfBDR which is not deenergized until the subscriber at A replaces his receiver. v s

The cord circuit Glmav also be .used to and another subscriberhaving a magneto type substation suchas M. In this case the initiation ofthe call by a, subscriber from a common battery substation such as A will be similar to the preceding ease up to. the mo-l merit, when the operator inserts'the calling I plug 'CPinto the magneto line'jack J7 In I this caseia circuit'is completed through the relays MS, CS and magneto line cut-ofi' relay C0 The latter having a high resistance will 180 have'now returned 907 reducethe-energiz-ing current to a margin whereof the three mentioned relays, only CS and CO? Will beenergized but not MS. The corresponding circuit can be traced from-the battery B of-relay CR, normal contact 115,

conductors 57 and 58, relay MS, conductor "59, relay CS,c0nductor 60, sleeve contacts of plug CP and jack-J relay CO? to ground;

As in the .previous'casethe energization of relay CS causes the energizationof relay 000. The operator now actuates the proper key of the party line ringing keys @PK as a, result of which the-end springs ES, by closing, complete an energizing circuit forthe relay IR traced from the battery 13 of-relay CS throughalternate contact 63, conductor 64, normal contact 66 of relay RDR, conductors 67 and 79, end springs ES, conductorSO, relay IR to ground. By-closing its contact 120 relay IR completes aicircuit for the relay RR traced tromthe battery B ofrelay-CS,

alternate contact-63, conductors 64 and 87,

relay RR, conductor 86., end spring ES, conductor 121, contact 120Uof relay IR, to ground. By closing itscontacts and 94 relay RR permits a ringing current to flow to the call bell of, the substation M over a circuit whose cord portion can be traced from the tip of plug CP over heavy conductor37, alternate contact 38 of relay IRxconductor V 88,'alternate contact 90. of relay RR, conductor .189, selected generator, generator common 9 ground Gr. conductor 95, alternate @contact :94

of relay BR. conductor 93, alternate contact 92 'ofrelay IR. heavy conductor 195 to the set to the :line by depressing the listening key LK through a circuit previously traced.

. However, the operators set-Oisdisconnected' from the calledasubscribers line-each time ringing current is applied thereto-by the .operatio'n of interrupter relay IR. w-When .the subscriber at M answers, the operator re,-

,-leases' the ringing key PK thus "opening the contacts-at ES as a result of which theener- .gizingicircu-itsio f 'IRand RRare interrupted,

said relays returning ,to normal :and-closing spring contacts 38 and 92 of relay, IR thus completing the heavily outlined circuitIin-the {drawing through which the subscribers are able to converse. v r

. 1 When, after the conversation has beenfin- ,ished Afhangs up his.receiver, he thereby breaks the energizing circuit of relay AB causing the releaseof the same as well as-of -.relay,AS and the energizationof relayQRas previously described. The relay CR ienerv. ,gi'zing breaks its contact 1-15 gthereby discon- Incase the call is being initiated by thesubcui t of relays andJQO? as previously traced. Italso. lights the supervisory lamp necting battery B from the energizingcin;

' AL to give adisconnect signal- Therelay .Co rreleasing puts relay LR? readiness tor- @flash the lamp L case ofj-recall ,by the subseriber at M. The release of CS causes the supervisorylampIOL to light and the relay IE. to -energize in the lsameln'anner as described in the .casepicommon battery to common 'batterycommunication. The remainder of the disconnect-operation is also similar. The entire disconnection is controlled by the calling common-battery station such as A.

scriber atM ,who desires TOCQIIVQISE with the l'subscriber at A, the former operates thehand generaito'rHM hich Will cause the .energi z,a-

' tion ofline relay LR? Zthe rusual nianner.

Thelatter attracts its-,arinatures 123 .and {125.

The attraction of armature 123 allows; the

-s pring l24 ted-rep downandas the relay LR is vdeenerg-ized, when the hand genera-tor HM is no. longer operated, the contact 12,5 returns to normal. .Gontact 123 is preventedfro n; returning .to normal bylthe construction of the spring124. circuit for the la-nipfL is now completed "and the samel-is lighted by a cur-' rent flowing tron; battery, Elamlp' L normal noticing the glowing :lamp1 TL an operator will insert an answering .plugAP-into one of thejacks J .A eircuitis now completed for ,rel aysfASand CO which ma yibe tracedirom battery throughrelay AS, conductor 15 norcontact 125 .to groundat spring 124, Uponthrough relay C0 The lattereneng nigfatsv tractsits =armature1-2 associated wit ,sp 124 which on nisingc'auses contact 123 tore-'1- turn and .exti,ngu'ishes,lam'p"L by interrupt ing its circuit :at :spring 12%. 'TheoperatOr .atrO is connected to the fca-l'ling subscniberfldue to the Operation Of rela ns and i Ia'bl'e to I talk to the subscriber through the circuit previously traced and tolearn ofhis wishes.

1 'llh e remainder otthe procedure andjoperation is the same as ;described"]inflthe case of munication.

common battery to common battery comv J r1 Ilhavesho. .n .thatat the time 'tliesubscrih.

.ersat AandM haveifinished their .conversa- "tion :the'subscriber at A-"by hanging his ,re-- I ceiver has :caused lbothlsuperyi'sory .larnp" 'AL and .CL to lightas. well; as the line ,l'ajrnpsfL j and. to vbeinf ,r,eadiness for :a r'recall. Of

the remainder ef relays, onlyQCR, .QCO and IR are .at this moment in ,operation, 'Iiinow' the subscriber at wishes to recall, he alter- :natel-y lifts andfldeposits his Ereceiyer, thus causing one or more short flashes of the line :lamp' L as a signal .to-theioper-ator. The latter new depresses her listening key LK "as a resultof which a circuit :is completed forthe -re ey$ nd 0,: saidhi fil' ll t e iggt '1 100 1 malffcontact 1*8,'.cond.uctor s Q14 {and Y13., sleeve V ucontacts of plug AP and jack ,J? toflgrofujnd j stood that '1 do notfdesirie tobe limited mule ames? for the initiation of'the callexcept neto type substations, a cord circuitl forc on- 7 that instead ofthe contact 18 ofrelayjOCO, which isrnow open, contact-130 of the listens ing keyLK is substituted, Relays AS, CO and *AB are energized'and relay CR deenelfgized, as previously" described. The rele'asef of the latter and'closing of its normal contact 115 causes theepergi'zation of relays CS and CO and the extinction of the supervisory lampsALand CL, While at thesame tlmllelay IR- is released thus once more complet ng the communication circuit between the two I "scribed including a plurality of subscribers" lines, some having common battery type sub stations and others having-magnetotype 's'ub- 33 stations, a cord circuit for connecting any: e two ofsaid-subscriberslines-in a 'conversaa subscribers, theintermediate operation "of the relays being as previously described.

I have showna n 140 incorporated in conductor 98 between contact'97 of relay ,MS and contact 9 1' of relay R-R'the purpose of which isto'damp the sudden rise of volt ageacross repeating coil P as a result of amomentary short "circuit which may occur during the shifting offspring contact 92 of relayIR, the: respective circuit comprislng :the'coil P,"-heavy' lead 131, alternate make before break contact 92, conductor 93, normal contact 94 of relay RlLresistance 140, altr- 3 a; 'conta ct 97 of relay Mspconductor 132 Resistance 14-1 incorporated -between contacts 1 O0-and of :relaysMS contact 38, of relay IR.

and RR performs the same service with re spect to repeating coil-P the momentary short circuit being liable to occur atspring lhavefshown also a contact 150 associated rfwunelay RR'the purpose of whichis to effect the discharge of the-energydue to the capacity of line duringthe ringing'operation when the line is alternately charged and discharged;

While""1'; have described a preferrediemexact [application as, illustrated and described", jbut intend ta-cover all such changes and, modifications as come within the sp rit f 1. A telephone system of the character de scribed including a plurality of subscribers f'lines,so meof said linesh'aving common battery substations and the remainder vhaving magneto ltype substations, a cord circuit prof v;de'd with means forinterconnect n'g any two ot' 'said lines, all of means operating m combination to providecommunication betweent-wo common;batterysubst'ations, and

some; oil-said means operating n combinat on to provide 1; communication between a common battery andf'a magneto type substafltionf J 23A telephone"systemfofjthe character de-:

"scribed including a plurality of subscribers lines, part being 'equipped rwith common" batte'ry type; substations andothe'rs with mag lines from saidjcord circuit.

' circuit provide sta-tion's, some of said relays being arranged to operate to completev a similar conversajtional circuit between a common batteryta'nd Y t "a magneto type substation, and means 'for: automatically disconnecting said subscriberis 1 lines-'from-'saidcordcircuit I 3. A'telephone'system of the character detion'al circuit, a set of cooperating-relays for i said cord circuitysome of said relays o'peratin'g'to' suitablyconnect and disconnectlthe e35 operatorsset associated with said cord circuit, and I means for causing the. disconnec ton to take place when the signalling circuit between two common battery subscribers lineshas been-Completed, and means- M1496 V automatically disconnecting said subscriberis V 4. A telephone system ofthe characteide- 7' -scribed including 'a plurality ofsubscrib'ers ilmes, part 'hav1ng"co1nmon battery and part magneto type i-subst'ation's, a cord,-circuit comprising" a set of cooperating relays for connecting'any two of said substations-into conversational circuit, a plurality "of-mam finally as well as automatically controlled ringing sources operating through"the"instrumentality ofsomeof said relays, a relay adapted a'utomatically to disconnect said I Y ringing sources and to maintain a major p0r-= i yt'ion of said conversational circuit intact'when aportion of the same,control1 edfromja con? i il ctedcommon' battery substation, has been i "interrupted; 1

" 5; In a telephonesystem ofthe characterl 'described'f including a calling js'u'b'scribers line-0f the common batterytypefland a called su'bscribers line of the magneto type, -a cOid.

necting means for sai'd'lines and with'two supervisory signalling 'means one for each line, and means whereby the common battery v subscriber at the end ofthe conversation; I

- automatically announces 1 disconnectfby ene'rgizingfbothsupervisory signals; j 6. A telephones stem of the characterderanged to i connect any two of said lines in 5 5 a conversational circuit, an operatofls set," V

automatic means for connecting and disconnecting: said "operators set tofand fromisaid t I cord c1rcu1t, individual 'automaticysuper-j.

visory signalling means for thecalling iand ff with automatic intercon- I i scribed including 'a cor d circuit,alplurality for the called subscriber, individual automatic recall signalling means for the calling and for the called subscriber, means enabling the subscriber at the common battery substation to automatically control his own supervisory and recall signalling means, and the supervisory means of the connected magneto type substation. r i

7. A telephone system of the character described including subscribers lines of the common battery type and subscribers lines of the magneto type, a cord circuit for interconnecting said lines, and disconnect sig nals for each line controlled over said common battery line. a

8; A telephone system including a'plurality of subscribers lines, part having common battery and part magneto type substations, a cord circuit for interconnecting any two of said substations, and disconnect signals for each of said lines, controlled solely by said common battery lines.

9. A telephone system including a plurality of subscribers lines, part having common Y battery and partmagneto type substations,

a cord circuit for interconnecting any two of said lines, and means controlled solely by the common battery lines for disconnecting said subscribers lines from said cord circuit.

10. A telephone system including a calling subscribers line of the common battery type and a called subscribers line of the magneto type, a cord circuit for interconnecting said lines, and means controlledby said calling subscriber for disconnecting said lines from said cord circuit.

Signed by me, at Chicago, in the county of Cook and State of Illinois, this 20th day of February, 1930.

BERT A. WALLACE.

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