US1770392A - Telephone system - Google Patents

Description

15, 1930. I 'r.-. F. cRocKER J 3 TELEPHONE SYSTEM 701 L BOARD v J6 a P1P ,3 AEZWM/F PS! PS4? PS 3| P6 4 Illllllll g lllllllll ill Imrsn ar Thumas F [Trucker July 15, 1930. 1-. F. CRO CKE R TE LEPHONE SYSTEM Filed Jan. 17, 1927 4 Sheets-Sheet 2 1m Thumas F." Cracker 5E 5N Q5 Sash 55: :3 SQ awk x5 July 15, 1930. RCROCKER TELEPHONE SYSTEM Filegl Jan. 17. 1927 4 Sheets- -Sheet 3 Inuanlnr' Thomas F Bracket PITT:

July 15, 1930. 1-. F. CROCKER TELEPHONE SYSTEM Filed Jan. 1'7, 1927 4 Sheets-Sheet 4 QE F pay station #4300. It is assumed that the connector C, and the automatic pay station APS are similar to the connector H and the substation A, respectively, shown in Fig; 3 of the drawings in the Wicks Patent 1,633,149, granted June 21, 1927. It is assumed further that the transmission selector repeater TSR issimilar tothe selector repeater shown in Fig. 2 of the above-mentioned drawings and hearing the general reference characters R, E, and F, except that a release trunk conductor is added to the trunk line comprising conductors 7 0 and 71 of the above-mentioned drawings. This conductor is an extension of the conductors connected to armature 17 8 of the release relay 152, and it is necessary owing to the fact 7 that the first selector F S is interposed between the transmission TSR and the jack J two-wire selector p r The lineswitches LS LS are assumed to be similar to the lineswitch O of the abovementioned patent, being of the ordinary rotary type.

It will be noted that a pay-station repeater PR has been inserted .between the bank of the lineswitch LS and the first selector F S This pay-station repeater is used primarily to collect or refund automatically a coin deposited at the pay station before a connection is attempted. t is assumed that the pay-station repeater PR and the'first selector F8 are similar to the pay-station repeater P and the first selector E in the drawings of the patent to WVicks No. 1,551,597, granted September 1, 1925.

It is assumed that there are a number of manual pay stations in addition to the automatic paystations. The lines from the manual pay stations terminate in jacks such as the jack J at the combined pay station and toll recordingboard. The calls bet-ween the manual pay stations and the automatic substations are handled by the pay-station operator, who is provided with a number of trunk lines extending to lineswitches, such as the lincswit-ch LS having access to regular first selectors. V

The trunk lines from'the tenth level of the regular first selectors extend to jacks such as the jack J at the combined paystation and toll-recording board. The operator at this board makes out the usual tickets concerning the desired connections and passes them over to the toll operator.

In order that the toll operator may set up connections involving the manual pay-station lines, transfer trunksare provided extending between jacks, such as J and J*, at the two boards.

Referring now to'Figs. 2-4, Fig. 2 shows the pay-station and tollrecording board. including the cord circuit CC the associated position equipment, the jacks J J and the selector repeater FS? is a standard line extending between the exchange and the manual pay station MPS. Fig. 3 shows the toll board, including the cord circuit CO the jacks J J and it indicates also the position equipment assumed to be similar to the'position equipment shown in Fig. 2. Fig. 4 shows the first selector FS terminating the toll line TL Detailed description The general descriptionof the system and the equipment having been given, a detailed description of the operation will now be proceeded with.

For this purpose it will be assumed first that a patron at the manual pay station MPS, Fig. 2, desires to converse with the subscriber at the automatic substation No. 4390, Fig. 1. V

OaZZ from pag station ill PS to Automatic Substation N0. 4390.

lVhen the receiver is removed at substation 'MPS,a circuit is closed over the associated line conductors for line relay 202 in the exchange. Line relay 202 operates and closes a circuit at its upper armature for the line lamp 204. At its inner upper armature it closes a circuit for the visual signal 205, and its multiples in other positions. Upon noting the lighted condition of the lamp 204, the operator inserts the answering plug of an idle cord circuit, for example the answering plug of the cord circuit (3C into the ack J When the plug has been fully inserted into the jack, a circuit is completed over the sleeve of the plug and jack for the sleeve relay 203, including the upper spring contacts of the jack J battery being connected in the cord circuit to the plug sleeve. Relay 203 operates and extinguishes the line lamp at its upper armature, at the same time closing a multiple circuit for the visual signal 205 and its multiples. At its inner armature, relay 203 disconnects relay 201, so as to prevent its operation at this time.

In the cord circuit, it will be noted that battery is supplied to the sleeve of the answering plug through the resistance 211, through the resistance 213 and contacts on relays 214 and 215 and 011 the talking and ringing keys, and through the supervisory lamp 212 and contacts on the relays and keys mentioned. The resistance of the upper winding of relay 203 is of suflicientvalue to prevent the supervisory lamp 212 from becoming lighted at this time. The operator now throws her talking key, whereupon the sleeve conductor of the plug is disconnected from relay 214 and the supervisory lamp 212 and is transferred to the position equipment. The resistance224 in the position equipment is sufficiently low to permit the marginal sleeve relay 203 to remain operated. As a further result of the throwing of the talking desireda'connectibn. fillponflearni'ng thattthe sig'z zogsea key, th'e "talking strands f the :cord circuit iare connected to the -tal:liing "conductors 1' of ithe oper'atoi'is head :set thro ughthe contacts of the ifollowing keys 2 iGollectvairswer, i-rRefund answer, Cut-01'1" answer, .and Dial call. The bperator HOW converses vvith 'thezsub- 's'criber and ascertains the :destination of the lIO the coin fall, the operatoriinsertsithe-'xzalling plu g of the :cordicircuit: into we 1 ack, :the ija ck ,J 1f -rgmmple, ofsaitrun'k rline iextending to a =line'sWi-tch.' UponYthelinsertio'nioi th'eipl ug into theijack .iT?, 2li'ClIiCui-t1lis :close'di a't the uper espringicontacts of the :jak 2 if-or Ithe, upper' windingiofithe relay 221, including the i'sieeviefoi thefplugiand j'ac'k. ilttitslinne'r upperiarmature,2relay22lLclosessa'ilcircuitrlfor :the:ipelariingwindingse'ftthe electropelarihed rrelayi222. This; winding .lisi composed of a relatively small number "of iturn's of Wire "lravingz-arconiparativly*high'lresistance; and rit i-a-lon e icannot therefore operati-vely energi ze ithe relay. At E its upper and lower armatures, relay1221 removes the a shunt from around ithe "talking condensers wand it closes a "bridge across the outgoing trunk conduc-.

itors including impedance '2231and the upper winding rofrrel'ay r222. The .curre'nt "Ifloxv in l the upper winding of relay 222 'now assists the 1 current flow in the lowerwinding,"- with the result that the relay operates and iconnects the lower 'w-inding of relay 221 between the sleeve of thev ljack and ground, thereby lowering't'he resistance of the sleeve circuit :suificiently to cause the supervisory lampfilfliinthe cord circuit'to'be'come lighted through :the lower "contacts of 1 the ringing key. The lineswitclfLS Fig. l,*n'ow Loperates and: seizes,f-'for"example," the selector'Fs The'operator' now throwsher Dial call-*ke'y in'herzpositioirequipment. v:Aztrits inner con- -ta'cts,,t'hiskeydisconnects the conduct-ors be- -:tween the' talking key and'the operatoi shead set, and-- at its upper'icontacts it" closes circhit througlrthelowertcontacts of the talking key :to'r the'c'o'r'd splittinghrel'ay 216. Relay 216 operates and closes'a connection' between t'he talkingvconductors Ofithe calling plug and thebperatorfsheadsetby wayi'otthe keys to thezriglitfdf the :Dial Icalh key, atith'e 'saine centimeters from he ri hehan' repeatingthe operators fhea dv'set,xoperates' .through the upperfcontactsofitheDial ieallekeyand shunts *0 the rasscciated meme-nee; rin f'the rcperator s talking conductors. v V c WVith the D al-foall-v-keywperated,fandfwith relay21 6 :(neerated, ggr'oilnd :Ifrom :the "lower :on the =fealling iplug, thereby Ishuntingipthe falls back, opening rthe bridge across the outgo1ngtrunk "conductors and openingithe circuitz otithepolarizing 'yvindingiof relay222 at the isarnezti'rne shunting the "talking moniden sers, ttherebyaconnecting the outgoingtrunk conductors Withatheitip: and zring' com :ductors ofathe ':calli1rg1 plug,' T which 'iareln'ovr connected: through their-ight h'an'd vkeysioffthe positio'nfequipment to? the loperators: head set; I

ith the .talkingicondenser '.in rthe: head-set shunted "byir!elayi 222 a "holding bridge exists in the OPGDELtOP- S' headset including norm ally closed "icontac-ts L on "relay 1223-, the balancing resistance; secon dary vvindi'ngs of the operators induction coil, and the: impulse springs -of1tlre :c'alling (device :-221. .Th-e linear-clay of the seized first selectornoW remainso'perated through this bridge. i w 7 The operator nowrmanifiulates the calling rdevice5f221c in accordance with the digits :in' the called r number 4390', With the result that the connection 'is extended from I the seized lfirst selector F3 :to the line extending "to substation 4390 through a second selector, the second :s el'ector SS, Fig.1-1, "forrexample, {and a connector, the -connector l "'for example. Upon being operated, the connector 0 'applies ringing current to the cal-le'dlinein the :usual manner. Y j Y :Afte'rshe has I finished? dialingqthe I nu inber ztheioperatorrestores the Dial call ke'y, thereby reconnecting the head set- With the talking conductors of the cord eircuitithjrough the 'springszof-theitalking key, removingground V fromithesleeve of the calling plug,=. and op ening-the 'circuit 'of relays 222 216. Relays.216;and 222- remain operated 1 for an interval=so as to holditheestablished 'connecxlish nentbf the bridge and the reoperation of relay 222 ,=-but it is relightcd when relayv 222 v operates and: closes the; circuitthrough the lower Winding of relay 221.

flavingfinishe d gdial'nglthe wett r-1150;;

crater nowi restores the-talking key. and turns to 'other duties. The-restoration of the talkingrkey eat this timeidees '1 not result in any relayoperation, as it-ni'erelyshifts the sleeve of-theanswerinplu-g iback torelay214; vand lamp 212.? in addition to-disconnecting. the cord ifrorn t-he common talkingieircuit. v

l'Vh'en the subscrib'ed -2at'-t-he .call'ed: substation cr Spo-nds :to the 'fringingxof 5 his h'ell iby v reir-iovin g his :re'ceiver, the iconneotor' Il re- "ver se's the :connectien abetween :itsiinceming itnunkzconductonszanidits batteryifeedfc'rrcuit,

1 therehyscausingqareversalrofzcurrent flew tin "'the circnitjrincliitling3rel9ky' 222, Figufiyasso- 'guished momentarily .pendi the ireestab ciated with the jack J When this occurs, relay 222 falls back and disconnects the lower winding of relay 221 whereupon the lamp 217 becomes extinguished as it does receive sufficient. current through the upper winding of relay 221' to remain lighted. When lamp 217 becomes extinguished, the

operator is notified thereby that the'called' subscriber has answered.

The two subscribers may now converse with each other as desired, and when the conversation is terminated they. both replace their receivers. WVhen the receiver is replaced at the called substation, the connector C reverses its incoming-trunk-conductor connections hack to. normal, whereupon the polarized relay 222, Fig. 2, reoperates, causing the supervisory lamp 217 in the cordcircuit CC to become lightedagain as a disconnect signal. l

Vhen the receiver is replaced at the man ual pay-station MPS, line relay 202 falls back and closes a lowresistance circuit between ground and the sleeve of the jackJ which circuit includes the lower winding of relay 203, normal contacts'ot relay 202, operated contacts of relay-203, and the upper springs of the jackJ \Vhen this circuit is closed, the lamp 212 becomes lighted, thereby giving the operator a disconnect signal from the calling station.

Upon perceiving the disconnect signal, the operator proceeds to take down the connection. Before doing so, however, she must collect the coin deposited at the manual pay station MPS. In order to do this she reoperates her talking key so as to connect the talking conductors associated with the answering plug to her position equipment through the left-hand 'keys'thereof, after which she operates her Collect answer key. \Vhen this key is thrown, ground is placed on thesleeve of the answering plug through the lower contacts of thekey, contacts of the talking key, and contacts of the ringing key. This shunts the'sleeve relay 203 in the trunk circuit associated with the jack Jflw'hereuponrelay 203 falls back and closesa'circuit for relay 201. Relay 201 operates and-disconnects line relay 202, at the same time shunting the associated talking condensers so as to give a clear circuit for the passage of the coin-collect current. At its remaining contacts, the Collect answer key disconnects the talking conductor from theoperators head set and connects them both to a source of positive current of substantially 110 volts potential. This closes a circuit which may include both sides of the line in case the receiver is oif at the called substation, but which includes only the upper talking conductor at this time, as the receiver has been replaced. This circuit includes the operating magnet at the pay station and this magnet is operated in the proper direc- ,usual manner.

tion to collect the deposited coin. When the key is restored, the coin control magnet at the pay station restores and it is thereupon disconnected from the talking circuit in the 'In' practice, 'tae operator is usually-pro vided with a supervisory relay in the coin control battery circuits so that she can reopcrate the key a second time to ascertain whether or not the coin has been actually collected, as the; magnet will still be con nected to the line if the coin has not fallen from the chamber.

lVhen the operator restores the collect key, ground is removed from the sleeve of the answering plug, permitting relay 203 to pull up and open the circuit of relay 201, whereupon relay 201 falls back and reconnects the line relay. Following this, the operator restores her talking key and pulls down the answering and calling plugs. QVVhcn the answering plug is removed, relay 203 fallsback and opens the circuit of the visual signal 205 and its multiples.

hen thecalling plug-is removed, relay 221 falls back and opens the bridge across the associated trunk conductors and opens the circuit of the lower winding of the electropolarized relay, whereupon relay 222 falls back and the connection through the automatic switches is released in the usual and well known manner. The entire connection is now released and the apparatus involved therein may be used to set up subsequent connection.

Call from pay station MP8 completed over to line TL It will now be assumed that a patron at the manual pay station MPS desires to con- ;verse with a subscriber in the exchange to which the. toll line TL extends. Accordingly, thesubscriber at substation M1 5 removes his receiver and gets intocommunication with the pay station and toll-recording operator, who makes a note of theparticular calling line and of the line to which the connection is to be extended. This note is made on what is known as a ticket, and the ticket is given to the operator at the toll board shown in Fig. 3. 1.

hen the operator at the toll board is ready to set up the connection, she inserts a plug of an idle cord circuit into the jack of a transfer trunk extending from the toll board to the pay-station board. In this instance it will be assumed that she inserts the calling plug of the cord circuit CC into the jack'J hen this occurs, relay 305 operates through the sleeve of the plug and ack, but lamp 213 is not lighted owing to the relatively high resistance of relay 305. Relay 305 closes a circuit through contacts of relay 246 for the signal lamp 2 1-5 associated with the jack J i i I swagger guishesthe-lamp 245. The-supervisory lamp 212' associated with" the answering-- .pl'ug-fof the cord circuit 6G is not lightedthis' time owing :to the fact-thatgroundpotential 15,-; other in the usual manner.

edg'out of'this timethat the: position equip ment at the toll board" isidentical with the position equipment at the pay-station and g5- plugsof the. cordare connectedtogether through. all theoperatOrs common keys in series until. the operator 1nanipulates-'one-of. the common keysto separate the-two plugs.

' has-been removed frointhe sleeve of jack' J? by the sleeverelay-305; of thejack J .The two operators now throw-their respec tive talking-keys and converse withea-c'h It may be;point-- toll+recording:board, except'that the branch conductor corresponding; to the one used forf operating-relay 243 is omitted in'the position equipmentofi'Fig. 3'. Wheneverthe operator at the tolllboard throws the talking key, the;

cordisplitting relay. 314 operates and the two Upon. learning that the toll operatorlis 1. settingupthe connection involving the manualipay: station MIPS, the pay-station operator: insertsthecal-ling plug of the cord circuit 06 into the .jackJ so as to reserve the line and prevent it from being'used in the ord i nary'manneruntil thetoll. call has been dis- 403- s snl s in,alish gy muit e g lo e posed ofthen theplug-is. inserted, relay 203. operates and shunts. its upper: windingthrougha circuit path including; its lower:

winding, the line relay 202 remaining normal.

for the supervisorylamp; 217-; The toll-recording and pay-station operator, however, does notsi'g-nai the subscriber at the manual pay stationi for. the; time being, but shevwaits 45.; until shev is-requested to do so by the toll.

operator.

The toll operator now inserts the answer-*- ing-p'lng ofithecord: oircuitCG into the jack of: anrid le-toll'. line, for example the toll line TL J; The-@busy or idle condition of the toll line, is indicatediby the conditionof the, visual 215 "vibrates several times in response to the busy; signal 303.. 'When the answering plug OfTthQzCOI'd' circuit CC? is inserted into the jacklflacficuit is closed over the sleeveof the. plugand. jack for the cut-off relay'302,

battery being, supplied to the. sleeve of the. plug, through; the resistance 311, and through the'resistance318 and: the lamp 315 by way-of contacts;otrclays-312and 3'131and ofthe talke ing'andring-ing-keys; Relay 302 disconnects the upper winding, of the. cut-off relay? .301

and; closes-a1 circuit forthe visu a1 signal 303.

' Theal-amp does aIIOUbQGOIHQ. lighted owing tel-the; relatively'high resistance; at relay. 302; 6e. Theoperaton new; throws: her" ringing key? and" the cumulativefefiect is that the relay operates and opens a further point in the" associated with theansweringplug, thereby projecting ringing current out over-thettoll' line T-Lv Itwill be notedthatthe ringing key also opens a point in the sleeve circuit; leaving abattery conneotionto thesleeve circuit onlythrough the resistance 311. This is for the purpose of'dropping back the sleeve" relay inthose circuits containing marginal andthat the called' subscriber responds, the originatingtoll operator then requests the called subscriber towaita moment while she gets 111 touch with the calling, subscriber. In

order to do this, the originating toll operator has two courses open. .She may withdrawand reinse'rt the callingplug of the cord circuit CC a' few times, with the result that each time she does so the disconnect lamp on the calling end of the cord circuit OC 'is flashed by the placing of ground potential on the sleeve of the when the sleeve relay 305 falls back. Asa-nalternative, thetoll opera tor may ring over the transfer trunk by operating the ringing hey associated with the calling end of the cord. This ringing key projects ringing current over the transfer trunk and inaddition opens a'connection in the sleevecircuit so that only the'resistan'ce' 317 isleft to supply battery to the sleeve.

The sensitive sleeve relay 305 associated with the jack J does not fall backwhen the ringing'key is thrown.

In the cordc1rcu1t 0C relay215 responds to the ringing current repeated through the repeating coil, windings and removes; the

shunt from around the winding of relay lar, which'copper collar is placed on the armature end of the relay core, as is indicated vRelay 214 it will be noted, has a copper-col- I by the .factjthat a solid black symbolisused. I The relay 214 is therefore slightly slow to r operate so as to prevent the lamp212fro'm being brought in in case a single stray impulse being received. :However, when relay ringing current, relay 214 has the short circult removed from around it several times shortcircuit, with the resultthat it remains operated after relay 215 has restored. At' its upper armature, relay 214 disconnect-stile lamp 212 from the sleeve circuit and connects it to groundwhereimdn the lamp 212 lights asacallingsignalf If desired, ground througha suitable interrupting clevlce instead of ground direct could be connected to one front contact of the upper-armature of relay 21 i so as to give a distinctive signal to the operator to lnform her that the lamp 1s lighted in response to the receipt of ringing current.

It may be that the ringingcurrent con-' not be depended on owing to the loss in the trunk circuit associated with the jack J owing to the line-relay bridge and the series talking condensers.

Upon noting the lighted condition of the lamp 212, the pay-station and'toll-recording operator throws her talking key and converses with the toll operator. Relay 21 i falls sack and the lamp 212 is extinguished when the key is thrown. Upon being informed that the connection is now ready, the pay-station and toll-recording operator throws her ringing key, associated with the calling plug, now in the jack J, whereupon ringing current is projected out over the line, and relay 203 falls back owing to the opening of the sleeve connection at the ringing key, this relay eing designed and adjusted soas not to hold up in series with the relatively high resistance 219. Upon falling back, relay 203 connects up relay 201, and this relay operates to disconnect line relay 202 and by pass the talking condensers, this operation being similar to that performed when the Collect-answering key was thrown to collect the deposited coin as hereinbefore described. As the line relay is now disconnected from in bridge of the conductors and as the talkin condensers are bypassed, theringing current base clear path to the manual pay station. lV hen the ringing key is restored, relay 203 reoperates and disconnects relay 201 whereupon the latter relay falls back.

When the call is answered at the manual pay station, the pay-station operator is notified of the answered condition by the extinguishing of the calling supervisory lamp 217. The operator now throws her calling key and she throws her answering Cut-elf answer key temporarily so as to prevent the distant subscriber from hearing her conversation with the patron at the manual pay station. The operator requests the pay-station patron to deposit coins of the correct number and value, being informed that he does so by the usual arrangement of gongs which are located in close proximity to the transmitter. After the coins have beendeposited, the operator throws her Collect call key,

whereupon the positive 110 volt source of cur- 7 rent is connected to'both sides of the talking circuit extending through the calling plug to the jack J and a ground potential is key the circuits are restored, after which the operator may restore her Cut-off answer key and inform the toll operator that the call ing subscriber is ready to converse. operator repeats this order to the subscribers and they proceed with the conversation.

lVhen' the conversation is over, the two subscribers replace their receivers. JV hen the receiver is replaced at the manual pay station, line relay 202 falls back and closes a low resistancejcircuit between ground and the sleeve of the ack J including the lower winding of relay 203. l Vhen this occurs, the calling supervisory. lamp 217 becomes lighted through the plug of the cord to give the operator a disconnect signal. lVhen the operator receives this disconnect signal, she throws her talking key and inquires whether the connection may be taken down; Assuming that the pay-station operator gets no reply, she throws the ringing key on the answering end of her cord, thereby projecting ringing current over the transfer trunk to the cord circuit (1C and also through the cord circuit C6 to the distant toll board. Relay 813 in the cord circuit CC responds to the ringing current and causes the operation of relay 312 which opens a further point in the previous shunt around itscwinding so that it remains operated after relay 313 has restored. Both toll operators throw their talking keys and the three operators converse with each other to be sure that the connection is not pulled down prematurely.

Upon ascertaining that the conversation is completed, the operators pull down the connection and restore their talking keys, where upon the apparatus reverts to the position shown in thedrawings.

Gall from substation ALPS completed over toll line T11 It will now be assumed that a patron at the automatic pay station APS, No. @300, in Fig. l, desires to converse with a subscriber in the exchange reached by way of the automatic toll line TL In this case the calling pays'tation patron removes his receiver, whereupon the lineswitch LS operates to select an idle first selector, for example the first selec tor FS When the calling device is operated in accordance with the digit 0 assigned to the toll recording operator, the first selector FS raises its wipers opposite the tenth level and selects an idle trunk line, for example he trunk line extending to the jack J shown in detail iniFig. 2. When this trunk line is seized, line relay 24% operates over the calling line and closes a circuit for release relay 2&3 and a multiple circuit for the lamp 241. Relay 243 operates and grounds the associated release trunk conductor at its upper arma- The toll sourceot ringing. current andtlie lower trunk I conductor This connection ncludesa condenser of a relatively small capacity with the result that aslight toneisplaced on the talking circuit-so as toinforni calling pay-m station patron thatthe toll.recording opera.-

tor is being signalled.v 1 This source or *inging.

' When this has been dne, the receiver is re in, I u a remalnsoperated i i-parallel witlrrelajy 242 cuit ()C into the jack J current is usuallythe; regular interrupted. source used in connectwn wlththe connecto switches,to s gnalcalled l nes;

hen the toll record ng; lighted condition ofthe la r the answeringplugofan idle co operatornotes the 2 11; $1. 6 l e chcirc'uit, for.

example the answering plug of .tnecord C11.-

When this; occurs,

a circuit is closed at the upper springcontacts of the aok J forrelay2 t2, whereupon relay.

2&2 operates and locksitselfrin multiple .with

release relay 243, at the same tiineientinguislk ing the lainp 24cl and disconnecting the tone source from the line.

Thetoll recordingoperator now throwsher talking key and converses with the calling} pay-station patron, rnaking out the usual ticket regard ng the desired connection.

place'dat the pay station, whereupon the re lay Qtfallsback. The plug maybe with fdensers; 1 Responsive drawn. from the jack J either; before or after this takes place. Assuiningthe plug'is with- 1 the jack J thefirstselector'FS 'is-prepared drawn before the pay-station patron hangs up, the original energizing circuit of relay 242 is opened at the upper. sprlngs oft-he geek.

and the answer ng supervisory lamp becomes lighted over the sleeveyotthe jacl' fand" the sleeveof the answering plug: 0 to,

sleeve of the jack by reley 244;; ,When the operator perceives this disconnect signalshe,

removes-the plug from thejaclt.

The connection won by the toll operator upon the receipt. the

the placing of a ground-potential on-fthe 1d ordinarily be up into the 'jack of an .idle'toll service trunlgz, for exarnple' the calling plug-of the-rordicrr;

serts the-calling pluggot'iane idle cord circuit cuit CC? into the jack J When this occurs, 5.

sleeve relay 82 l-operates over the sleeve the'tplug; and jack; and; throughftlie upper.

springs e f-the ack;the ground potential be ing suppliedto;the'gupper terminal of the reasto prevent lp ossible preliminary impulses due. to careless or-hesitant insertionsof the v plugs into-the jack. Relay; 32% closesa.

bridgeracrgoss theoutgoingt-runkconducto s5 including relay. 325- and the? nnpeuance win d 1I1g327 R-elay' 325; operates in this brldge' and connects relay 326 in inulti-ple iwith the lay; only after the: plug .is fully inserted so:

upper winding ofjrelay Relay 3200p 1 erates and shunts 1ts upper 'WiDClIDg. Relay.

32filisrprovid'ed'with a relatively highu-e-x sistan'ceiupper-winding so as to enableitto operateg quickly, and :thisfawinding. is shunt-W- ed 'soas to. permit the calling.supervisory.-.

lamp in, the-cord circuit to become: lighted at this: time through the lower windings of re-;

.lays 324D and. 326. Relay 326.- also. removes the shunt: from around. the associated? con? tothe closure oi thebridge across. the trunk conductors outgoingfrom I for: operation in the usnalfmannerp her talk.

The pay-station operator-throws;

ingkey in the cord circuitCG after which she throws her. Dial callzkey, resulting inth'e operation of, the cord splitting IBlay-QlUfiD'Cl lnthe placing of ground on the sleeve of 'the plug through contacts of the Dial call hey and contacts of relay 216.- v When this occurs; relays 32 lzian'd 326 associated with the v jackLJ both fallback, but relay 326- falls back sooner thanrelay 824' owing't'o its: mar

ticket callingfor theconnection, and a cord circuit such as-the cord circuitCC would be used. the pay-station and toll-record1ng operator However, in order to explain how',,

may help out the toll operator when the.

necessity rises, it will be assumed thatthe pay-station opera-tor handles the conneetzon ginal adjustment. Relaylti opens the bridge, but,'pri'or'to that, the bridgeis re f established-around the condensersassociated with relay 326; and includingthe right handkeysat the operators position equipment and the "operatorshead set conduc'tors,'- ref-- .flay 222having beenoperated in the manner previously'pointed out bythe upper contacts of the Dialcallkey to-shunt the associated condenser; The operator now manipulates her. calling device 1n accordance witlt the digits in the number of the-callingpay Station, whereupon the connection isset up" tothepay station through the'toll'train and -inay include jin addition to the first selector F82 justrecorded owing to a peakdeinand for] toll. connections. tions are located side by side and the pay- The. two operators 1 posistation and toll-recording operator may rea chover into the toll position with her own plugs and set up connections through the toll board;

with the pay-station cords. In this case, the. pay-eta tionv operator. in

able when needed'. 1

the connector C rent upon beingoperated, but the pay-station line is made busyto the other-connectorshavl ne Wlll he avai-L ing access toit so that the The pay stationo the. transmission selector repeater TSR and- I p I he connector-isarranged so-thatat does not startto apply ringingcurperator now inserts the l answering plug of the cord 'ci'rcuit @6 into the jack associated with an idle toll line in the groupto which the toll line TL belongs, the toll line jack J 6 for example. Vhen this occurs, relay 411 operates through its upper winding, and through the sleeve of the jack and plug, disconnecting the lower winding of the ring-up relay 412 from across the asso ciated talking conductors, and connecting the talking conductors 403 and 404 of the jack J with the corresponding conductors associated with the right-hand repeating-coil windings, at the same time removing the dialing connections from conductors 403 and 404. As a further result of the insertion of the plug into the jack, a circuit is closed at the upper conductor being connected to battery through the middle upper armature of relay 411 and the resistance 413. The distant impulse receiving relay, corresponding to relay 415, Fig. 4, operates and prepares the associated selector corresponding to the selector FS for operation in the usual manner.

The pay-station operator (now acting as the toll operator) has two courses open to her she may ring out over the toll line TL and have the distant operator set up the connection in any way she sees fit or she may dial the connection up through the distant automatic switches in case the called line is an automatic line. present case that she doesthe latter. In order to do this, the operator throws her talking key associated with the cord circuit (3C Fig. 2, after which she throws her Dial answer key, resulting in the operation of the relays 222 and 216 in the manner hereinbefore pointed out and in the placing of ground on the sleeve of the answering plug through operated springs of the talking key and normal springs of the ringing key. hen this is done, the cut-off relay 411, Fig. 4, falls back because its upper winding is shunted. At its middle upper armature it opens the connection through which battery wasinitially supplied to the upper limb of the toll line TL at the same time connecting up the dialing branches of the conductors 403 and 404, conductor 403 being connected to battery through resistance 413 and conductor 404 being connected to the upper limb of the toll line TL through the working contact and upper ar mature of relay 414. It will be noted that the efiect of this is that the bridge including Itwill be assumed in the the operators head set and dialing equipment shown in Fig. 2 is inserted into the battery feed to the upper limb or" the toll line across the gap opened at the middle upper armature of relay 411. It may be pointed out, of course, that the contacts of relay 411 are so adjusted that this change is made without a inomentary loss of current through the toll As the loop circuit over'the toll line TL now includes the impulse springs of the calling device221, Fig. 2, the operator may now dial the number of the distant subscriber, whereupon the distant relay corresponding to relay 415, Fig. 4, responds with the result that the connection is set up to the desired line. The operator may, of course, restore her dial answering key as soon as she has finished dialing, whereupon relay 411 operates again shifting the battery supply circuit of the toll line back to its original path through the middle upper armature of relay 411.

Assuming that the desired line is idle and that the called subscriber responds, the paystation operator requests him to wait a moment while she signals the calling subscriber. In order to signal the calling subscriber, the pay-station operator throws the ringing key of the calling end of her cord circuit CO whereupon the lamp 217 is extinguished and the marginal relay 326, Fig. 3, falls back owing to the disconnection of the supervisory lamp 217 from the plug of the cord, but the sensitive relay 324 remains operated so as to maintain the bridge including relay 325 and impedance 327 closed. when relay 326 falls back it shunts the associated condensers so as to permit sufficient ringing current to pass through to result in the calling line being signalled. These condensers are of small capacity so that in case a distant operator should ring over a toll line when this trunk is connected with the toll line the condensers will block the ringing current so as to prevent the premature signalling of the originating subscriber. When the operator restores her ringing key, relay 326 reoperates and the lamp 217 relights. The connector C responds to the ringing current and signals the pay station intermittently in the usual manner.

WVhen the pay-station patron responds to his recall, the current flow over the trunk conductors outgoing from the jack J 8 is stopped in the transmission selector repeater TSR, Fig. l, in a manner explained in the application hereinbefore referred to. WVhen this occurs, relay .325 falls back and disconnects relay 326, whereupon the lamp 217 becomes extinguished owing to the fact that it cannot glow in series with both windings of relay 324. The operator now requests the pay-station patron to deposit the proper coins, which are collected upon a momentary operation of the Collect call key and in a manner simliar to that described hereinbefore in connection with the call from the manual, pay station MPS. Itmay be pointed outthat relay 216 in the cord is operated, and that relay 324 restores responsive to the placing of a ground potential on the plug sleeve.

.After the collectingoperation, the two subscribers may converse With each other inithe usual manner.

VJ hen the conversation is terminated, the two subscribers replace their receivers. Nhen the receiver is replaced at the pay station, the currentfiow over the trunk conductors outgoing from the jack J isreestahlished,

Whereu on rela 325 reooerates and connects relay 326 in multiple with the upper winding 01" relay 324.. When this occurs relay .326 shunts its own upper winding the lamp 217 lights again as a disconnect signal.

Upon perceiving the disconnect signal, the operator listens in versation is over, and upon pulls down the connection.

the release or finding it is. she This results in normal conditions.

0.13am toll Zine TL to am No. 2,390 It will now be assumedthat the operator in. the exchange to which tllGYtOll-llIlQ TL extends receives a ticket calling for connection to be set upv to linelNop4-390, Fig. 1.

. this occurs, the bridged rela-y 415'in thefirst v of the toll line v v in the inannerhereinhefore explained n con- When the distant operator is ready to'setup this connection, she inakesa connection with the toll line; TL through a'jack similar'to the jack JG, Fig. 3, whereupon a source of current is placed across the two conductors TL at the originating end nection with the first selector F53 When selector FS operates and 'closes a circuit for release relay 416.v Release relay 416 grounds the release trunk conductor 406fat its upper armature, at the same time opening afpoint' in the circuit of releasemagnet 420 andfin circuit of relay414 At 1ts lower armature,

relay 416 prepares a circuit for vertical magnet 421. Signal 323 and its multiples become. operated over conductor 406 to ind cate the busv'condition oi the trunk line.

When the calling operator dialsithe 'iirst digit 4 in the desired nuinbenrelay 415 falls baclr jfour times. Each time does so it closes a circuit for. vertical magnet 421- throng-lithe series relay 417. Relay 417 O1)- erates when the first impulse-of current is dea liver-ed, and, being slow acting, it remains operated. until the last impulse is received. Upon operating, relay41'! prepares a'circuit, which is closed when the switch noves on normal, from the grounded release trunk conductor'406 (now grounded at the-upper armature of relay 416) for. relay 418thr'ough the associated ofi-nor1nal contacts. Belay to inake sure that the conthe automatic switches and in" the restoration of the other circuits to their 418 operates upon the closure of this circuit and closes at its upper armature a locking circuit for itself including the interrupter contacts of rotary magnet 422. At its lower armature, relay 418 prepares a circuit for magnet 422' V p Itusually happens that ring up relay 412 operates responsive to the first interruption in the line current, due to the self induction.

of relay 415; Relay 412 closes its locking circuit in the usual manner, but it is disconnected and falls back right, away due to the operationof relay. v411 through its lower winding by oiienorn al contacts of the selec tor. The'local toll operator is therefore not signalled. I

I When series relay 417 falls back at the end of the digit, it closes a circuit for rotary.

magnet 422'inc1uding the grounded release trunk conductor 406, whereupon magnet 422 operates and rotates the wipers 431433 one step; Near the end of its stroke,.magnet 422 opens the circuit of stepping relay 418, whereupon relay 418 falls backand opens the circuit of rotary magnet 422. Magnet 422 falls j back and closes its interrupter contacts again.

The further operation depends "upon whether the trunk line is busy or idle. If

this triuik line .is idle, it is immediately seized I tinues'gin the usual manner until. an idle'line s reached, which trunk line, it will he assu1ned, is the. one comprising conductors 434 -436 and extending to the second selector SS. -;Wl1en this idle trunk line, is reached,

relay 419, having'heen short circuited' previously by the ground potentialjencountered bytest wiper 432, being nolonger short circuited, now operates from ground on the release trunk conductor 406 and inser es with stepping relay 418 and .the associatedjoilnormaland interrupter contacts. Upon op:

crating, relay 419 opens apoint in the verti cal magnet circuit at its inner lower a'rmavture ;;opens a further point in the L'QSt' ClICllll] and grounds test-wipers 432 at its inner upper armature so as to make the seized trunkbusy immediately; and at its upper and lower armatures connects. up the wipers 431 and433: When the wipersare connected up, the line relay (not shown) otthesecond selector SS;

1, operates over conductors 434' and 436,

wipers .431and 433, upper and lower tures of relay419, left-handrepeating-coil windings, andthe .lower;armature of relay 41'5.- The second selector SS is thereby prepared for operation in the ,us'ualn'ifanner.' 5

When the calling operator dials the next digit 3 in the desired number, relay 415 of the first selector SS falls back three times. Each time it does so it opens the bridge across the wipers 431 and 433, with the result that the wipers of the second selector SS, Fig. 1, are raised opposite the third level in the usual manner, whereupon the selector proceeds to select an idle trunk. It may be assumed that the trunk selected is the one extending to the connector C Responsive to the dialing of the last two digits, 9 and 0, the connector C raises its wipers opposite the ninth level and then retates them into engagement with the tenth set of bank contacts in that level and auto matically appl es ringing current to the line of substation No. 4390.

hen the called subscriber responds to the ringing of his bell by removing his receiver, the toll operator at the distant exchange is able to converse with him, and she instructs him to wait on the line while she completes the connection.

The connection may be completed in the distant ofiice in any well known or desired manner.

- Vhen the connection is pulled down by the distant operator, relay 415 falls back. and opens the circuit of release relay 416 at its inner armature, and at its lower armature opens the bridge across the line wipers, with the result that the second selector SS and the connector C release in the usual manner. The release of the first selector S is effected by magnet 420 upon the falling back of release relay 416, the release circuit including the associated off-normal contacts, which open as soon as. the normal position is attained.

All z mmlcs busy at the first selector F8 but its operation is of no particular utility.

The eleventh rotary step contacts connect a source of busy signalling current across the talking conductorsso as to inform the calling operator or" the busy condition. 'The selector releases in the above described manner when the operator in the distant. exchange pulls down the connection.

Call from the toll Zine TL 250. the toll Zine TL Assuming now that the v operator in the exchange to which the distant end of the toll line TL isextended takes the toll line TL for use to complete a connection through the toll board shown in Fig. 3 to the exchange to which the toll line TL extends, the selector FS is prepared for operation in the usual manner. Instead of dialing, however, the calling toll operator projects ringing current out over the toll line TL whereupon relay 412, whose lower winding is bridged across the right-hand repeating-coil winding in series with a condenser, responds to the ringing current repeated through the repeating-coil windings. Upon operating, relay 412 closes a locking circuit for its upper winding at its upper armature, and at its lower armature grounds conductor 401, lighting the call lamp 321, Fig. 3. When the toll operator notes the lighted condition of the lamp 321, she inserts the answering plug of an idle cord circuit, for example the answering plug of the cord circuit CO into the jack J When this occurs, a circuit is completed over the sleeve of the plug and the sleeve of the jack for cut-ofi' relay 411. Relay 411 operates and unlocks relay 412. At the same time itdisconnects the lower winding of relay 412 from in bridge or" the talking conductors; connects said conductors with the branch leading to the jack; and disconnects said branch from the dialing conductors. Relay 414, it will be noted, is not operated at this time owing to the fact that its circuit is open at the upper armature of release relay 416.

The operator at the cord circuit 06 now throws her talking key and converses with the calling operator. Upon ascertaining the destination of the call, the toll operator inserts the calling plug of the cord circuit CO into the jack of an idle toll line leading to the desired exchange, for example the jack J of the toll line TI WVhen this is done relay 302 operates over the sleeve circuit and disconnects the upper Winding of relay 301, at the same time closing a circuit for the visual signal 303 and its multiples. The operator now throws the ringing key associated with the calling end of the cord circuit 0C thereby projecting ringing currentout over the toll line TL Relay 302 does not tall back at this time, as it is eesigned so as to remain operated in series with the resistance 317. 1

When the connection set up between the toll line TI) and TL is to be talren down, the op rator at the cord circuit (1C is in formed of this fact upon the receipt of ringing c .rrent over the toll line lL which ii current operates the ringing response Belay 313 removes the shunt from .round relay 312, whereupon relay 312 oper- .s and opens a further point in its previouslypnisting shunt, and at its lower armat re closes a circuit for the disconnect lai'np 315. The operator at the cord circuit CS reoperates her talking key, and, when told to do so, takes down the connection,

whereupon relay 411 restores.

l Vhen the distant operator pulls down her cord, relays 415 and 416 fall back and ground is removed from conductor e06, restoring the visual signals at the toll-board positions.

When an automatic subscriber desires to call to a manual paystation, he dials the digit 0, whereupon the connection'is extend-- ed to the pay-station and toll-recording board in the manner previously explained. The operator responds and completes the connection through a cord circuitsuch as the cord circuit CO Fig. 2. 9

It will be notedthat the usual monitoring key is shown in connection with the cord circuit CO This monitoring key is used in case the operator desires to listen on .a connection to discover whether or not the sube scribers arehavinganyditficulty in understanding each other, and it is arranged to in-' crease the impedance of the operators head set by operating relay 223 to place the rece1v'-.

er in s ries with both secondary windings of the operators induction coil. A similar key is providedat the cord circuit 0C What is claimed is: i In a telephone system, an operators switchboard, linkcircuits at said switchboarchaposition equipment at said .switch board arranged to supplement anylink cir cuit and including talking conductors having man repeating coil'in each link circuit'dividing the talking conductors thereofinto'two in. ductively coupled sections, m ans including a manually operable key individual to each link circuit for connecting one section of the talking conductors thereof to said position equipinenta relay individual to each link circuit and arranged to connect the othersection of thetalkin conductors thereof to said position equipn'ient, andan operating circuit for any one ofsaid relays including conta'cts oi one of the manually operable keys in the position equipment and contacts ofthe' said manually operable keyin the same link circuit.

2. In a telephone system, an operators switchboa rd link circuits at said switchboard, a position equipment at said-switchboard including talking conductorshaving' manually operable keys connected therein", a

the two sections of any split link circuit,-.an operators callingdevice associated with said.

ally operahlerkeys connected-therein, a

atelephone system, operatorslink common connections, and means for opening the common connection between said calling device and either'section oi said link circuit. a. In a telephone system, an operators link circuit, means for splitting said link circuit into two sections, circuit connections commen tosaid link circuit and to other similar link circuits for bridging the gap between thetwo sections, a calling device connected in circuit withthe operators headset, ci.r-

cuit connections betweenthe calling device and the operators head set and said common 7 equipment, and means in said common equipment for opening the connection between the calling device and the operators head set and either section of the connected link circuit.

-5. In a telephone system in which connec tions through automatic switches are set up through an operators switchboard, link cir, cuits at switchboard through which said connections are extended, a calling device common to said link circuits for controlling the'automatic switches, means individual to each link Cllclllt' for connecting said calling device to both ends of such link circu1t, and

7 means common to said link circuits fordis connectin said callin device'from either end of a link circuit in use while leaving it' connected to the other end of such link circuit.

' .6. In a telephone" system in which connections including pay stations are, set up through an operators switchboard, link circuits at said switchboard through'which said connections are extended, a position equipment at saidswitchboard common to'all said link circuits, means individualto each link circuit for associating the link circuit with said position e cpu'ip'mentand means in the" position equipment for disposing of'coins' depos ted said pay stations. In a'telephone system, an operators switchboard, link circuits thereat for setting 7 up talking paths between telephone lines, each link circuitcompr sing, two sections,

means including a talking key and a relay,

individual toeach link circuit for dividing the link'circuit into its two sections, circuit connections common to all said link circuits andcontrolled bj SalCl key and relay for by pass ng theopenpoint in any link circuit,

anda circuit for said relay extendin g therev to from said common equipment through;

contacts ofsaid key. v 8. In a telephone system,

swi.

an operators hboar'd, link circuits at said switchboard-including talking conductors, means for dividing anylink c rcuit into two secti'ons, an impulse' sending calling device,-

ineans for completing a connection froin thef operators' head set and the calling device to one section of a divided linkwandfor completing. a separate connection from said op e'rator shead set and the calling device to the, other section of such l1nk,a control key in one connection common to all the link circuits, and another control key in the other connection common to all said link circuits.

9. In a telephone system, an operators switchb ard, automatic switching apparatus, a plurality of link circuits at said switchboard for use in completing telephone connections via said automatic switching apparatus. a talking key individual to each link circuit, circuit arrangements such that when the talking key is thrown a connection is established'from the corresponding l'nk circuit to the operators head set and calling device, each link circuit comprising two normally connected sections, and means common to all the link circuits for enabling the operator to connect. her head set and calling device with either section of a link circuit at which the talking key is thrown to the exclusion of the other section of such link circuit.

10. In an operators link circuit, a supervisory lamp arranged to be lighted or not under the control of current flow over the sleeve conductor of the link circuit, a ringing current responsive device in said link circuit, and means for lighting said lamp when the said device responds to ringing current regardless of any flow of current over the sleeve circuit.

11. In a telephone system, a plug ending operators link circuit, a supervisory lamp connected to the sleeve of said plug, and means in said link circuit responsive to the receipt of ringing current for disconnecting said lamp from said sleeve and for closing a lighting circuit for the said lamp.

12. In an operators switchboard, a link circuit terminating in a plug, a cooperating jack. a supervisory lamp connected to the sleeve of the plug, a holding relay connected to the sleeve of said, jack, a supervisory re lay associated with said jack, circuit arrangements controlled by said supervisory relay for regulating the current over the sleeve of the plug and ack to control the lighting of the said lamp, and circuit arrangements ted with said plug for regulating the current flow over said sleeve to control said holding relay.

13. In a telephone system, an operators switchboard, a link circuit at said switchboard terminati g in a plug, a cooperating jack, a supervisory circuit including the sleeve of the plug and jack, a supervisory relay associated with said jack and arranged to be controlled over the talking conductors extending tromthe spring contacts thereof, circuit arrangements whereby the current flow over the sleeve circuit is controlled in accordance with the normal or operated state oitsaid supervisory relay, and means associated with said plug for controlling said supervisory relay over said sleeve circuit.

14;. In a telephone system, an opera ors switchboard, a jack at said switchboard, a line extending from said ack divided into two ind uctively coupled sections, a plug-ending link at said switchboard, and means in aid line controlled over the sleeve of the plug and jack "for bypassing or including the inductive coupling in the connection of said line at the will of the operator at the switchboard.

15. in a telephone system, a manual switchboard, an automatic switchboard, a trunk line extending from a jack at the manual switchboard to said automatic switchboard, said trunk line being divided into two inductively coupled sections, a switch-holding path con nected to the autoniatic-switchboard section of said trunk line, a callin device at said manual switchboard for controlling the switches in the automatic switchboard, a plug for associating said calling device with said trunk line through said jack, and means under control. of the operator for by-passing the inductive connections between the two sections of the trunk line and for removing the switch-holding connection fromthe second section of the trunk line so as to place the mechanism at the automatic switchboard under the control of said calling device.

16. In a telephone system, a manual switchboard, an automatic switchboard, a trunk line extending from a jack at the manual switchboard to said automatic switchboard, said trunk line being divided into two inductively coupled sections, a switch-holding path connected to theautomaticswitchboard section of said trunk line, a calling device at said switchboard, a plug for associating said cal ing device with said trunk line through said jack, and means controlled over the sleeve of the plug and jack under the control of the operator for by-passing the inductive connections between the two sections of the trunk line and for removing the switch-holding connection from the second section of the trunk line so as to place the mechanism at the automatic switchboard under the control of said calling device.

17. In a telephone system, a manual switchboard, an automatic switchboard, a trunk line comprising two inductively coupled sections extending from said manual switchboard to said automatic switchboard, means for setting up a connection through said automatic switchboard controlled. from the manual switchboard, the inductive connection be tween the two sections being of such a value as to bar the passage of ringing current, and means responsive to the operation of a ringing key at the manual switchboard for enabling ringing current to pass over the two sections. 7

18. In a teleghone systen amanual switchboard, an automatic switchboard, a trunk line comprising two inductively coupled sections extending from said manual switchboard to said automatic switchboard, means for setting equipment.

up a connection through said automatic switchboard controlled from the manual switchboard, the inductive connection between the two sections being of such a value as to bar the passage of ringing current, means automatically responsive subsequent to the completion of the above connection for by-passing said inductive connections to facilitate the flow of talking current, and means responsive to the operation of a ringing key at the manual switchboard for enabling ringing current to pass over the two sections.

19. In a telephone system, a manual switchboard, an automatic switchboard, a trunk line extending from a ack at the manual switchboard to the automatic switchboard, said trunk line comprising two inductively coupled sections, a calling device at the manual switchboard, a control circuit for the switches at the automatic switchboard in cluding the two conductors of the second section of the trunk line in series, and means for placing the calling device in series with one side of the second trunk-line section over a circuit path including the two sides of the first section of the trunk line in series.

20. In a telephone system, an operators switchboard, link circuits at said switchboard, each including a pair of talking conductors and an auxiliary .conductor, llnes terminating at sa1d switchboard having correspondmg conductors, operator-controlled means for connecting the said conductors of any one of said link circuits with the corresponding conductors of any one of said lines, a position equipment at said switchboard arranged to supplement any link circuit and including conductors corresponding, respectively, to the said conductors of said link circuits, means for connecting the said conductors of any link circuit with the corresponding conductors of said position equipment, a plurality of operators keys in each link circuit, and a plurality of operators keys in said position 21. In a telephone system, an operators switchboard, link circuits at said switchboard, each including a pair of talking conductors and an auxiliary conductor, lines terminating at said switchboard having corresponding conductors, operator-controlled means for connecting the said conductors of any one of said link circuits with the corresponding conductors of any one of said lines, a position equipment at said. switchboard arranged to supplement any link circuit and including conductors corresponding, respectively, to the said conductors of said link circuit, means for connecting the said conductors of any link circuit with the corresponding conductors of said position equipment, means operable at the will of the operator at said position for exercising control over the said conductors of said link circuit through the medium of said conductors of said position equipment, and means in each link circuit for sending ringing current out through either end thereof independent of said position equipment.

I 22. In a telephone system, an operators switchboard, link circuits at said switchboard eachincluding a pair of talking conductors and an auxiliary conductor, a repeating coil in each link circuit dividing the talking conductors into two inductively coupled sections, lines .terminc ting at said switchboard having corresponding conductors, operatorcontrolled means for connecting the said conductors of any one of said link circuits with the corresponding conductors of any one of said lines, a position equipment atsaid switchboard arranged to supplement any link circuit and including conductors corresponding, respectively, to the said conductors on any one of said link circuits, means for connecting the said conductors of any link circuit with the corresponding conductors of said position equipment, and means operable at the will of the operator at said position for exercising a control over the connected link circuit through the medium of her position equipment. I

23. In a telephone system, an operators switchboard, link circuits at said switchboard each including a pair of talking conductors and an auxiliary conductor, lines terminating at said switchboard having corresponding conductors and having coin-controlled equipment connected thereto, operator-controlled means for connecting the said conductors of said link circuit with the corresponding conductors of any one of said lines, a position equipment at said switchboard arranged to 7 conductors corresponding, respectively, to the I said conductors of any one of sa1d link cirsupplement any link circuit and including cuits, means for connecting the said conductors of any link circuit with the corresponding conductors of said position equipment, means including manually operable keys in said position equipment for exercising either of two controls over the said conductors of a line through a connected link circuit via said position equipment, and means responsive to said controls to collect and refund coins, respectively, at said coin-controlled apparatus.

24. In a combined manual and automatic telephone system, an operators switchboard, link circuits at saidswitchboard, a talking key for each link circuit, a calling device at said switchboard common to all said link circuits, operator-controlled. contacts individual to said calling device but forming no part thereof and being operable separatetherefrom, and means responsive to an operation of said contacts "for operatively associating said calling device with whichever link circuit contains an operated talking key.

25. In a combined manual and automatic telephone system, a plurality of link circuits each comprising two sections, a calling device, a manually operable key for each link circuit for determining with which link circuit the calling device is to be associated, means common to all link circuits and controlled by the operator for determining with which section of the linkcircuit the calling device is to be associated, means included in said connecting means for directly connecting the calling device with one section of a predetermined link circuit, and means including means individual to each link circuit and part of said 1 common means for connecting the calling device to the other section of a link circuit.

26. In a telephone system, an operators switchboard, link circuits over which talkmg connections are to be set up, a position equipment at said switchboard arranged to supplement any link circuits in a plurality of Ways, means for associating said position equipment with a link circuit and for operating the position equipment to supplement the associated link circuit in exercising any desired one of a plurality of controls over the connection extending through the link circuit, and means individual to each link circuit for projecting ringing current out over any connected line.

In witness whereof, I hereunto subscribe my name this 12th day of January, A. 1).,

THOMAS F. CEO CKER.

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