US1631351A - Automatic telephone system - Google Patents

Description

' V Y 1631] .1 June 7, J. wlcKs I AUTOMATIC TELEPHONE SYSTEM Origifial Filed May 6- 1920 '4 shuts-Shari Jnhn Hicks Q Q I 79 June 7, 1927. v J. wlcKs 1 631 51 AUTOMATI C TELEPHONE S YSTEM Original Filed May 6. 1920 4 Sheots-5heet 2 I7.'LUETL UPI- Jul-m Mafia %4: 77 T I:

J ne 7, 1927.

J. wxc s AUTOMATIC TELEPHONE SYSTEM Ofiginal Filed May 6. 1920 4 Shoots-Shut 3 any:

Jun 7 1927.

- J. WICKS AUTOMATIC TELEPHONE SYSTEM mwQ \w mum MMQUMH WN \W h.\\\

Original Filed May 6. 1920 Juhn lnficks HIT:

Patented June 7, 1 927.

tlwHTfD j sra'rss [JOHN WICKS,0F OAK rARK, ILIJINOIS,-ASSIGNOB, -BY MEs vE A SSIGNMENTS, '10 AUTO- MATIC ELECTRIC -INC.,-OF CHICAGO, rumors, .a-oom oan'rion OF DELAWARE.

- AUTOMATIC TE ErnouE sys'rniva,

original application filed May 6, 1920, Serial No. I 1921, Serial No. 458,174.

My invention relates in general to automatic telephone systems but is concerned more particularly with methodsof handlmg long distance'calls in'such systems; and the object of the invention, in general, is to pro- ;vide anew and improved toll service trunking system for connecting local subscribers in automatic exchanges with long distance lines, either as calling or called subscribers.

Toll service trunking systems of character have been known before, and reference is made to my U. S. Patent No. 1,315,444, issued on Sept. 9, 1919, which shows and fully describes a modern system of toll service trunks. Reference is made, furthermore, to my pending application, Serial Number 364,069, filed March 8 1920, which shows a toll service trunking system especially designed for use in a telephone system where the subscribers stations are equipped with coin collecting devices or paystations; and the system .of the present application may properly be considered .as an improvement on the system disclosed 1n the latter application. Thisapplication is a division of my application bearing Serial Number 379,217 filed May 6,1920, which issuedlVl-ay25 1926, as Patent "No/1,586,057.

More-specifically, then, the principalobject of the invention may be stated to be the provision of a new and improved toll service trunking system, containing suitable circuit arrangements and other provisions whereby the toll operators can connect with desired calling or called lines which are equipped with paystations, and can thereafter collect or refund deposited .coins as occasion requires. It. may be mentioned that the paystations intended to be used are f the type commonly known as Gray pay- .stations. which are shown and described in,

theU. S. Patentto-Forsberg, No. 1,043,219.

- i In addition, there'are a number of other improvements which have more to .do with the trunking system itself and are not especially connected with the measured service jleaturc. Those 11nprovem-cnts, however, are

perhaps of .a minor character and will be pointed out in the course of the detailed specification, which will now he proceeded with. v V i licferring to the drawings, comprising Fig-5.1, 2, '3 and .4, l' have shown therein by the above 379,217. Divided and-this application filed April 2,

Renewed. November :7, 1925.

, means of the usual circuit diagrams "the lap tion, station A,Fig. 4. This apparatus comprises the cord circuit, Fig. 1, located at a toll-operato "s position in a toll switching station or ofiice; the :two conductor trunk line extending from jack J in the toll 1 Fig. 2, in a main exchange of the system; the toll transmission repeater E; the toll second selector F, Fig. 3; andth'e combination' toll and regular connector .H, Fig. l. The-repeater, second selector, and connector "mentioned are in the same office or exchange as the toll first selector D,- which as indicated above may vbeone of the main offices "or exchanges of a large multi oflice system. i

In addition to the above I have also shown means which .is common ItO all the trunk lines extending from the "toll switchingoffice to the local office, and which is used to collect or refund deposited coins at* any switching ofiice to the toll first selector D,-

subscribersstation, suchas station A, which I is connectedwithvia the-toll servicetrunkmg system, This add tional means'or appzn-atus comprises the special cord circuit- TC), Fig. 1,'ithese special cord circuits being supplied "at the rate of one or two per-post t1on; the trunk line extending from jack in the toll switchingoffice 'to the local office; and the special connector M, 2,

in which the said trunk line terminatesand which has access, to all the tollfirstse'lec-u tors such asthe se'lector D.

In view of thefwell .known character of the 'apparatusan'd the descriptions thereof in the publications previously referred to, I will notdescribe such apparatus in detail inthexpresent application, bu'twill proceed at once to explain the operation of th eflcircuits with: aviewto pointing outthe new For this purposeit will p be assumed that. the subscriber Qat substa- V improvements.

"tion A, .FigJl, has 1 placed a long distance .call with a toll recording operator and that the ticket containing the usual data 0011-,

cerningtfhe desiredconnection .hasbeen for-1 wardcd to the toll'operator having the cord circuit 0, .Fig. 1, for completion;

ljl aving extended a connection to the desired distant exchange: over one of her toll tors 30 and 31 in series.

lines, as for example the toll line which terminates in jack J, Fig. ,1, and having ordered the proper local line'to be connected up in thatcxchange, the toll operator will next proceed to call the subscriber at substation A by way of the toll service trunking system. Observing that the toll service trunk terminating in jack J is idle, as indicated by the unlighted condition of the busy lamp L the operator will insert the calling plug of cord circuit O in the said jack J, the double throw listening and calling device key K being thrown to'calling position at the same time. Upon insertion of the plug in the jack J a circuit is completed for relays and 21 in series; and the latter relay, upon energizing, lights the busy lamp L at its armature 23, establishes a locking circuit for itself at its armature 24, and at its armature 25 prepares .a circuit whereby relay 22 may later be bridged across the trunk conductors and 31, this circuit being open for the time being, however, at armature 26 of relay 20,

which relay pulls up in series with relay 21. It is understood that the outgoing trunk jacks and lamps are multiplied at other operators positions in the usual manner, and the multiple busy lamps at the other positions are of course lighted in parallel with lamp L The key K being. in calling position, as before stated, the operators head set, including the calling device S in series therewith,

' will be bridged across the upper and lower strands of the. cord circuit, resulting in the closure of a circuit for the line relay 51 of the toll selector 1 over the trunk conduc- Upon the comple-- tion of this circuit the line relay 51 ,is energized and closes the circuit of the slow acting release relay 52. Upon energizing, the latter relay prepares the selector switch for operation in its vertical movement in the usual manner.

The toll. operator will nowoperate her calling device S in accordance with the telephone number of the subscriber at substation A. hen the calling device dial is operated in accordance with the first digit of the number, a series of interruptions is produced in the circuit of the line relay 51 of.

the toll selector D. The line relay 51 is thereforedeenergize-d a plurality of times corresponding to the digit called, and at each (leenergization sends a current impulse through the slow acting series relay 53 and the vertical magnet 56 to battery. By the operation of the vertical magnet the switch shatt is raised step by stop until the wipers, -73, inclusive, stand opposite the horizontal level of bank contacts which are terminals of trunk lines leading to the desired thousand group. The slow acting relay 53 is energized in series with the vertical magwhich they were raised.

net, maintaining its armature continuously attracted during the vertical operation of the switch, and at the first upward movement of the switch shaft closes a circuit for the stepping. relay 54. Upon energizing, relay 54 establishes a locking circuit for itself at its upper armature and at its lower armature prepares a circuit for the rotary magnet At the end of the vertical movement of the switch the slow acting relay 53 is de energized and completes the aforesaid circuit for the rotary magnet, which is accordingly energized and advances the wipers 70-73, inclusive, into engagement with the first set of bank contacts in the level opposite Near the end of its stroke the rotary magnet breaks the locking circuit of the stepping relay 54, which is ac-' cordingly deenergized to open the circuit of the rotary magnet. Both the rotary magnet 57 and the stepping relay 54 having decnergized, the operation now depends upon whether the test contact with which the test wiper 71 is in engagement is busy or is not busy. If this testcontact is busy, it will have a ground potential upon it and a'circuit will be established by way of the said test wiper whereby the stepping relay 54 is again energized to again close the circuit of the rotary magnet 57, which in turn operates to advance the switch wipers into engagement with the next set of bank contacts. This operation continues as long as the test wiper 71 continues to engage grounded test contacts. As soon as the first non-grounded test contact is reached, which we will assume to be the test contact 75 associated with the trunk line extending to the repeater D, the stepping relay 54 will not again be energized, and the rotary movement of the switch.

coming trunk line conductors and 31 from the windings ot the line relay 51 and extends them. by way of wipers 70 and 73 bank contacts 74 and 77, left hand windings of the repeating coil. R, and normally closed contacts of the relay 101'to the upper and lower windings, respectively, of the line re-' lay 104 of the toll transmission repeater R.

The line relay 104 is accordingly energized and closes a circuit for the slow acting release relay 105 which, upon energizing in turn, closes the talking conductors through the repeater by means of its 'arinatures 115 and 118, and also at its armature 116 completes a holding circuit in the usual manner which extends by way of conductor144 back to the selector D where it serves to maintain the switching rela 50 energized throughout the connection. round potential is also placed'on the multiples of test contact 7 5 by means of this circuit in order to make the selected trunk busy to other selectors.

When the line relay 1040f the repeater E was energized as previously explained, a con trol or operating circuit extending to the line relay 151 of the toll second selector F, Fig. was completed as follows: ground G armature 126 and its working contact, conductor 143, armature 160and its resting contact, and the winding of the line relay 151 ed by the line relay to battery. Upon the closure of the above circuit the line relay 151 is energized, and completes a circuit for the slow acting rethe usual manner. Upon lease relay 152 in 152 grounds the release energizing, relay trunk conductor 144 locally at its upper armature, and at its lower armature prepares the circuits of the selector for the vertical operation thereof. I

The toll operator may now operate the dial of her calling device S in accordance with the second digit in the number of the subscriber at substationiA. The interrupthis operation are repeat- 104 of the repeater D, and cause a series of deenergizations of the line relay 151 of the selector F. "While the line'rela'y 104 is repeating impulses to the line relay 151 it also sends a series of impulses throughjthe slow acting relay 106, which operates to disconnect the A. C. relay 121 and also to short circu'itthe lower hand winding o'tthe repeating coil R. These operations render the control circuits more efficient. The toll second selector F is very similar to theselector E and its operation therefore will nottbe des'crib'ed in detail. It will be sufii'cient to say that the dcenergizations produced by firms of the line relay 151 bring about the operation of the vertical magnet 156 through the medium of which the switch shaft is raised step by step untilthewip'crs 170-173,

inclusive, stand opposite the horiz'ontallevel of bank contacts which are'terminals of trunk lines lead ng to the desired group or connector switches. .The slowacting relay is energized in serieswith the vertical magnet-and at the first upward step of the shaft-"closes the initial energizing circuit of the steppingrelayf154 byway of the off normal contact springs 159. The stepping relay 154 looks itself as usual and prepares a circuit for the rotary magnet 157 At the end of the vertical movement of the switch, the SlOWQ'CtlDg relay 1531s deenergized and the switch wipers are rotated in searchof an idle 'trnnlcline by me-anscot the rotary I right v magnet 157, whichris controlled by the stepping relay 154 and the test Wiper 171. When an ldle trunk line is reached, Wl11Cl1 we Wlll assume to be the trunk line comprlsing'condoctors 178181',inclusive, the rotation of .the switch will cease, leaving the Wipers 170-172, inclusive, in engagement "with bank contacts 174-177, inclusive. The

switching relay 150is now energized and at its armatures 161 and 163 connects thetallo' ing conductors 141 and 145 with the line is included in the control circuit of the toll conductors 17 9 and 180. The conductor143 selector F, and when it is extended as above i mentioned, the linerelay 151 and'the release relay 152 of the selector are of course deenergized, the selector beingmaintained in operated position by the continued'energization of the switching relay 150, which is supplied with ground over the conductor 144 coming from the repeater E. 4 i

The switch control circuit having been extended, as above stated, to the conductor 180. it may be further traced by way of thesaid conductor 180, the upper winding ofthe relay 204 of the combination connector H, v Fig. 4, contact springs controlled by the back bridge relay 200. and the upper Winding of the line relay 201 to battery. Upon the extension of the control circuit over the above path, the line relay 201 is energized prepares the connector for vertical operation in the usual manner. At its upper armature 218, relay 202 connects ground G with the release trunk 'conductor'305, which con-.

ductor extends to and is multipled in the banks of the second selectors of the regularv exchange trunking system which have. access tothe combination toll and regular connector H. Conductor 305isthe release trunk conductor of the trunk line co1nprismg conductors 304, 305 and 306 which ter minat'e in bankcontacts 301, 302, an-d;303,

respectively, Fig. These bank contacts are assumed to be located 'in the banks of one ofthe regular selectors referred to,- and the ground potential upon conductor 305, and the test contact 302 and its multiples. endertheconnectorI-I busy, 7 r

A branch of conductor 305 may be traced from junction point 306. by way of conductor 305,.w-inding of relay'207, conductor 179, bank contact 175,,wiper 171, armature 162 and its working contact, conductor142, "armature 128i and its resting contact, and

the resistance 111 to battery. By current flow over the above circuit the/relay 207 is energized and at its armatures 236 and 237 prepares circuits for the Ting cut off relay 205 which will be explained later.v Relay 1207 also closes a circuit for the switching of enabling it to function as a toll connector rather than as a regular connector. hese circuit changes include the opening of the permanent locking circuit of the ring cut oil".

relay 205 at armature 225, the shifting of the locking circuit of the busy test relay 200 at armature 22 1, the disconnection of the regular trunk line conductors A and 306 at armatures 223 and 226, and the preparation of a supervisory signalling circuit for the toll operator at armature 223. These circuit changes and the results effected thereby will be mentioned more in detail hereinafter. Before proceeding further with the explanation a few more details concerning relays 207 and 204: may he inserted with benefit. Relay 207 is of relative 1y low resistance, and the circuit traced through its winding from the grounded conductor 305 to the conductor 179 and test contact 175 places a potential upon the said test contact 175 and its multiples, which sufficiently near to ground potential to render the connector H busy to the toll second selectors. Withregard to relay 20 1, the upper winding of the relay, which is included in the circuit of line relay 201, is of low resistance and is not necessarily strong enough to energize the relay by itself,

- but is strong enough to hold the said relay in operated position after it has been completely operated by the closure of the circuit through its lower winding. In order to reduce the impedance of the upper winding so as not to interfere with operating impulses transmitted to the line relay 201, the relay 204 is provided with a copper slug as indicated in the drawing. Theconnector H is now ready to be operated under the control of the calling device S, when the dial is actuated in accordance with the next digit in the number of the subscriber at the substation A. A series of interruptions is produced as before, which are repeated by the relay 104: of the repeater E to bring about a series of deenergizations of the line relay 201. At each deenergization the line relay transmits a current impulse through the vertical magnet 210 over the following circuit: ground at Glarmature 215 and its resting contact,

. armature 216 and its working contact, off

normal springs 222 and 220, winding of the slow acting series relay 203, and Winding of the vertical magnet 210 'to'battery. This is the circuit over which the first impulse is transmitted. At the first upward step of the switch shaft, however, the off normal springs are shifted, and the circuit extends from the working contact of armature 216' by way of off normal springs 222 and 221, armature 217-and its working contact, (relay 203 being now energized), winding of the relay 203, and the winding of the vertical magnet 210 to battery. By the operation of the vertical magnet the switch shaft is raised step by st-epuntil the wipers 2'70 272, inclusive, stand opposite the level of bank contacts in which the line of substation A is terminated, The slow acting relay 203 which is energized in series with the vertical magnet, maintains its armature. attracted throughout the vertical operation of the switch. lVhen this relay energizes at the beginning of the vertical ncrement it closes the following circuit for the ring cutoff relay 205: ground at G armature 218 and its working contact, armature 219 and its working contact, working contact of armature 237 and. the said armature, and the lower winding of the ring cut-off relay 205 to battery. Upon energizing, relay 205 opens contacts included in a later established signalling circuit at its armatures 227 and 229,-and at its armature 228 establishes a locking circuit for itself as follows: grounded conductor 305 working contact of armature 228 and the said armature, armature 236 and its working contact, and the lower winding of relay 205 to battery. At the end of the vertical movement of the switch, the slow acting relay 203 deenergizes and prepares thev connector for operation in its rotary movement.

The toll operator may now operate the dial of the calling device S in accordance with the final digit in the number of the subscriber at substation A. The interruptions produced are repeated as before through the medium of relay 104, and cause another series of deenergizations of the line relay 201 of the connector H. At each deenergization the line relay now sends a current impulse through the rotary magnet 212 over the following path: round at G, armature 21f and its resting contact, armature 216 and its Working contact, off normal springs 222 and 221, armature 217 and itsresting con tact, resting contact of armature 233 and the said armature, armature 246 and its resting contact, and the winding of the rotary magnet 212 to battery. In response to these impulses the rotary magnet operates to rotate the wipers 270-272, inclusive, into engagement with the particular set of bank contacts in which the line of substation'A terminates, these bank contacts being the contacts indicated .in the drawing by the reference characters 273, 274i, and 275. The slow acting relay208 is energized in parallel with the rotary magnet and retains its armatures attracted throughout the rotary movement of the switch. At its armature 239, relay 208 connects the test wiper 27].

to the winding of the busy test relay 206, and at lts arniature2 l relay 208' closes a shunt around armature 233lof'relay200and its resting contact to-guard against, the possibility of the said relay being momentarily energ zed wh le the test wiper 271 is passing over busy test contacts. 'In order to,

ford an opportunity to explain the operation of the busy test circuits. it will be assumed that when the line of substation A is called at this time it is busy. in such case the test contact 27% will be gl'OllHfilfiCland when the test wiper 271 makes connection with the said test cont-,act, th.e test relay 200 will be energized, the circuit being traceable as follows: grounded test contact 27 4, test w per 271, contact springs controlled, by armature 1 2&4; of relay 209, armature 2,39 andits worln ing contact, armature 2 43 and its resting contact, and the winding of the test relay 206. to'battery. The test relay is energized over the above. circuit and when. the slow acting'relay 208 deenergizes at the end of the rotary movement of the switch, the test relay becomes locked upby means of the following circuit: grounded test contact 274, test wiper 271, worklngcontact of armature 224 and the said armature, working contact of armature 230 and the said armature, con tact springs controlled by armature 239 of relay 208, armature 2&3 and its resting con.- tact, and the winding: of the test relay 206 to battery. The various circuit changes et fectedby. the operation of the test relay will now be briefly pointed out. Its locking circuit which is closed at armature 230 has just been explained. At armature 231 the circuit of the switching relay 209 is opened,

at armature 232 a shunt is connected aroundthe armature 236 of relay 207 and its workingcontact in order to prevent accidental deenergization of the ring out ofi relay 205 (by movement .of ringing key at the operr ato-rs cord circuit), at armature 233 the circuit of the rotary ,rnagnet 212 is opened in ,order to prevent the switch wipers from being rotated ofi the contacts of the called line, and at armature 235 a lead from the busy signalling machine Q is connected to however, removing the plug from jack J in order to prevent the busy tone from passing out over the'toll line, When key K restored the supervisory relay ,6 is connected I in bri'dgeot the trunk conductors and 31 in, place or the operators head setfand this I relay 6 would be energizged in series with I the line relay 1,04 of the repeater E were it hotter the fact that the connectorHis wait- 1 ingon a bnsv line, In order to nuake this clear a circuit will be traced which was conipleted. by the busy test relay 206 and which extends as follows 2 ground G resting contact of armature 2 11 and the said ari'naQ U-'9 a 'rmture and t r n contact working contact of armature 223mm the said armature,conductor 1 78, bank contact. 174, wiperv 170, working contact of arms ,ture 161 and'the said arn ature, conductor & armatu e 1.2 aud ts r n a t rmat e 1. and it W k n n a t; upper ig t andv W nche of peat g coil' 3 and the winding. of re ay 1.00 to battery.

en lew thf ab ve, l' ri er e to pel ate relay which closes a circuit forthe elay 10. Uro iener z ns the la te relay d sconnects the ncoming. trunk line cong ductors from, the windings of theline relay 1.04 and at the sa ne time closes a local ci'r cuit tor the upper winding ot the said line re ay- T e X a e batt s t ir e t y is q me t d fr m e t unk in a d ll be v dent, ac rdingly, ha he uperv r relay 6 willnot be energized and the lamp L will not be lighted.

lVhen the line o f substation A becomes idle, ground potential is re noved fro n the test contact 27,4; andthe locking circuitof the. test relay 206 is broken The test relay th r re l i e izesr li wnneets. t e bu y signalling machine opens the circuit oi? relay 10.0 at the repeater E a n d establishes a circuit for the. SWitGhing relay 209 wh ch may be traced as follow'sf grounded conu o 4 5, armat re contact, upper winding of theswitching relay 209, resting contact 0t armature 2 3 9. and

231 and 7 its resting h -sa d ar rr co ct plines co roll d 1 y ar a 2 4 t t W r ,2 l, test nta t 274;, winding of the switching relay 3l7 ol the individualline switch C, and ,the winding of the, stepping magnet-318m battery. Upon the, closure of the above Circuit relays 209ar1cl 1,7 a ene gized in seri nd th latter relay is operated to disconnect the line conductors 3 20w andl3'21 'frorntheir-norrnal connections inthe line switch. Belay 317, is not completely ,operated because of the ilfact that the line relay of the line switch has not been energized, and does not connect-the line conductors, with the wipers of the l ne switc I th .eqnne H, th el y 209 p en rg z a ep n the ci cu t o he tary magnet 2 12 at armature 246, establishes a locking circuit for itself at armature 2&5 ce n a round G tovth te t ipe I at armature 2%, thus closing the circr iit of the switching relay 3117 of the line switch over a new path excluding the upper windmg of relay 209 which was formerly Mk I cluded in the circuit, and at armature. 242

and 2&7 closes the talking conductors through to the line wipers 270 and 27 The connection has now been established w i th'the line of substation A. hen the busy test relay 206 is deenergizcd and the connector cuts through onto the called line as described in the preceding paragraph the circuit of relay at the repeater is broken as previously stated, and this relay and also relay 101. are deenergized. The incoming trunk conductors are therebyconnected again to the windings of the line relay 10d and current is supplied to the bridged supervisory relay 6 at the operators cord circuit. Relay 6 is therefore ener-- gized and lights the supervisory lamp L to advise the operator that the called line has become idle and that connection thereto has been completed.

The next operation is to ring the subscriber at substation A. For this purpose the operator throws the key K momentarily to ring ing position, thereby projecting ringing cur rent out over the trunk line with which the cord circuit 0 is connected, to operate the alternating current relay 121 at repeater E.

Upon attracting its armature 128, relay 121 breaks the previously described circuit of the relay 207 at the connector I-I. Relay 207 accordingly deenergizes and at its armature 236 breaks the locking circuit of the ring out oif relay 205. Relay 205 then deenergizes and at its armatures 227 and 229 opens the talking'conductors and establishes the usual signalling circuit which includes the ringing current generator Gen, and its own upper winding. There is no special novelty in the signalling circuit itself although it is be lieved that the provision of a pick up relay, which is rendered necessary by the fact that semi-selective ringing is used. is new in an. automatic system of this kind. As shown herein, the line of substation A is a party line, substation A being a so-called two bell station while substation A is a one bell station. The operations following the deenergization of the ring cut off relay. 205 may be explained more in detail as follows: .lVhe-n relay 205 falls back, a circuit is prepared at its armature 281 for the pick up relay 282, and as soon as the pick-up common conductor 285 becomes grounded during a silent period the said circuit is closed. Upon energizing, relay 282 locks itself at its armature 283, and at its armature 284 finally closes the signalling circuit, after which the bell at substation A. will be rung automatically as long as the receiver remains on the hook. During the ringing operation the operator is given the well. known ringing current induction, provided of course that she is listening on the line. to notify her that the ringing is proceeding satisfactorily. This is accomplished by means of the inductive path which extends from armature 247 of relay 209 by way of the low capacity condenser 299 to the resting contact of armature 235 of relay 206. Condenser 299 is of very low generator Gen, or by current from the exchange battery in series with the booster battery associated with the generator, and upon attracting its armature 228 will reestablish its former locking circuit, the operator having restored her ringing key by this time to permit the energization of relay 207. The ring out off relay also disconnects its own upper winding andthe ringing apparatus at its armatures 227 and 229 respectively, and closes the talking conductors at these same armatures. The transmitter at substation A is now supplied with talking battery through the winding of the battery feed relay 100 at the repeater E; This circuit will not be traced in detail but it will be observed that the lower line conductor extends uninterruptedly back through the connector H and the selector F to the lower ri ht hand winding of the repeating coil R, w ience it extends through the resistance 113 to ground, while the upper line conductor 320 extends back through the connector H and the selector F to the upper right hand winding of the repeating coil R, from which point it may be traced through the said winding and through the winding of the relay 100 to battery. Relay 100 is energizedby cur rent flow through the transmitter at substation A, and upon attracting its armature closes the circuit of relay 101, which again operates to close a local circuit for line relay 104i, and breaks the circuit of the supervisory relay 6 at the operators cord circuit, thus causing this relay to deenergize and extinguish the supervisory amp L The completion of the local circuit for the line relay, it will be noted, removes the release of the connection from the control of the op erator.

The operator will now come in on the line again by throwing her key K to listening position, and after ascertaining that the proper person is at the telephone, willrequest such person to deposit the correct coin When or coins to pay for his connection.

the coins are deposited the operator is given an audible signal over the telephone circuit in the usual manner so that she will know the toll service trunk system.

that' the right amount has beengdebosited, and also the polarized magnet of the paystationis connected to theline in order that the operator may thereafter either collect or refund the coins. 1

Everything is now in'readinesstor con versation to begin, at least so far as the connections to the party at substation A is concerned. rissuming'that the desired party as been obtained in the distant exchange, the operator will now complete the connection at her cord circuit and the connected parties can converse as desired. It will be observed that the connection includes twocon-ductor trunk line from the toll switching station to the main or local exchange (the trunk comprising conductors 30 and 31), which 1s a decided economy over tormer arrangements requiring at least' three, and

u sometimes cren tour conductor trunk lines.

Another advantage which may be pointed out is found in the arrangement by which the called subscriber controls the rel-ease 0t theconnecti'on, while his receiver is oil, through the-medium 0t relays and 101,

the latter of which controls a local circuit for the line relay 104;. This arrangement makes it possible for the toll operator to change cord circuits after a called party has answered without releasing the established connection.

Whenthe connection is finished both subscribers will hang up their receivers- Upon the replacement of the receiver at substation A, relays 100 and 101 at the repeater E are d'eene-rgized and the line relay 104 is again connected across the conductors: of the incoming trunk line. As a result the supervisory relay 6' at the operators; cord circuit is energized and the lamp ii is lighted to give the operator a disconnect signal. Before releasing the connection the operator will have to collect whatever coins were deposited, andthis plain-ed. v

[he trunk lgine extending from jaclnJ in the toll switching station to the connector M in the local exchange and comprising conductors 351, 3-52, and 3-53 is one of a limited number of similar trunks which are used exclusively for I collecting and refunding operations. Any one of these trunks may be made use of to collect or refund at any,

subscribers station in the local exchange in question which has been connected with via When the toll operator gets ready to collect, then, 'on the connection just described, she will insert the plug of special cord circuit 0 in the drawing is the one taken for use. .lVhen the jack of an idle collect trunk. and we will assume that the trunk line shown in the plug is inserted in jack J? circuit is completed over the sleeve of the ack which includes the calling device S and the relay operation will now be ex 350 in series. Upon energizing; relay 350 lights the busy lamp L and its multiple lamps at other positions '(not'shown), and

also closes a circuit over trunk conductor which includes the line relay 360 of the connector M at the distant "local exchange.

Upon energizing relay .36'0'closes a circuit for the slow acting release relay 361 which the toll service trunk line inuse in the connection forwhich it is desired to collect, it being, understood that all the toll service trunks extending to the local'excha'nge' in question are numbered consecutively in accordance with the bank numbering otthe connector M and associated connectors. Assuming that connector Misaone hundred line switch, it may have access to one'hundred toll service trunks numbered from 01 to 99. To proceed, when thecalling device S. is operated in accordance with the first digit-of the number, therelay3'50 is deenergized' a plurality of times, causing alike plurality of deenergi'zations ot the line relay 36.0 of the connector The latter relay controls the connector M in substantially the same way that the line relay 201 con trols the combination conn'ector;H"'and on that account, the explanation :Will not be given in detail. Briefly, at each deene'rgiza tio-n, line. relay 3'60 sends a current impulse through the vertical magnet 367 which operates to raise the switch shaft step by step until the wipers 370, 371,-and 372 stand opposite the level in which is terminated the branch line which-is a multiple of the particular-toll service trunk to be collected over. Theslow acting series relay 362 is energized in series with the vertical magnet,

maintains the vertical magnet circuit intact after the 'ott normal springs have shifted at the first upward step of the shaft; and att'he end of .the vertical moven'ient' deenergizes and shifts the operating circuit to the rotary magnet 368.

When the calling device S is operated in accordance with the next and last digitin the number, theline relay 360sends a series of current impulses to the rotary magnet 368 which in response thereto operates to rotate the wipers 370-372 inclusive, until they. come to rest in engagement with bank contacts 373-375, inclusive. At the first rotary step the rotary oii norma'l'springs 369, which are included in the rotary inagnetcircuit, are separated, but the. magnet circuit is maintained closed by theslow acting series relay 3% unt l the la t rot y pu se s 1e trunk line will be easily understood.

ceived after which the said relay deenergizes and the magnet circuit is opened.

An independent connection has now been established wit-l1 the toll service trunk by way of the collect trunk and the connector M. \Vhile the toll operator is operating the dial of calling device S to establish the branch connection she has her listening key K in the cord circuit in operated position and as soon therefore as the connector M establishes connection with the branch comprising conductors 300, and 31, and the slow acting relay 363 has deenergized, the operator is given an audible high frequency tone which notifies her that she has connected with the proper toll service trunk. This tone signal'is provided to prevent any error in collecting which might arise due to faulty manipulation of the calling device or faulty operation of the connector M, either of which would cause connection to be established with some other toll service trunk.

than the one over which it is desired to col- 3 lect. If the operator does not hear the tone 7 she will know that something is wrong and facts 373375, inclusive, the secondary of the induction coil is bridged across the branch conductors 30, 31, resulting in the transmission of an audible signal to the operator as stated.

Having perceived the O. K. signal, the operator will immediately operate the collect key in the cord circuit 0. By this operation the exchange battery at the toll switching station is bridged across the trunk conductors 351 and 355 and a flow of current is produced in the winding of relay 365 and the lower winding of the electro-polarized relay 364, these relays being bridged across conductors 351 and 353 at the connector M. When this current flow is established, relay 364 is not operated, due to the opposition of its polarizing winding; but

relay is operated and closes the following circuit: from the positive pole of ground battery B through the resistance lamp in series therewith, resting contact of armature 381 and the said armature, armature 382 and its working contact, winding of marginal relay 366, wiper 371, bank contact 374, conductor 300, armature 63 and its working contact, wiper 7 2, bank contact 7 6, conductor 130, winding of relay 107, and the high resistance 199 to ground. Current flew in the nects conductors 141 and 145 to conductor 130. A relatively low resistance branch path to ground is thus established which is in parallel with the relay 107 and resistance 109 and which may be traced readily by way of conductors 141, 178, and 320 to the substation A, through the polarized magnet of the paystation mechanism to ground. Battery B is a high voltage battery and produces a current flow in the above traced branch circuit which is in the proper direction to operate the polarized magnet to collect the deposited coin or coins, the paystation mechanism be ing reset at the same time. When the branch circuit through the polarized magnet is established the resulting current flow is suflicient to operate the marginal relay 366 and this relay upon attracting its armature 383 substitutes an interrupted tone signal for the continuous tone signal, thereby advising the toll operator that the collect circuits are all right'and that presumably the coins have been collected. The collect key is now restored and relay 365 is thereby deenergized. whereupon the battery 13 is disconnected andrelays 366, 107, and 108 are deenergized. Also, since the paystation mechanism at substation A has been reset by the polarized magnet, when the battery 13 is disconnected and the polarized magnet is thereby permitted to restore its armature thesaid magnet is disconnected from the line. The toll operator will now operate her collect key once more, thereby again connecting battery B to the line of substation A as before described. This time, however, since the polarized magnet at the paystation has been disconnected the marginal relay 366 will not be operated and the operator will not get the interrupted tone back on the line. By this the operator knows that the collecting operation has been successful and she will again restore the collect key.

If the operator desires to refund a deposited coin rather than collect it she may do so by operating the refund key instead of the collect key. Assuming the same circuit conditions to exist as in the previous case, where the operator collected the coins, if the refund key is operated the exchange battery is connected in bridge of trunk conductors 351 and 353 as before, except that it is reversed, and as a result the electro-polarized relay 364 at the connector H is operated as well as the relay 365. It follows that battery B will be connected to the line of substation instead cf battery B and battery whence the circuit extends B" being of the opposite polarity, the deposited coins'are refunded instead of 001-1 lected. Except as pointed out, the refunding operation is the same as the collecting operation, and the operator is given supervision by means of the interrupted tone 1n the same 1 way.

The special collect trunks are used only for collecting or'refunding, which takes but a few seconds, and are at once restored to common use. When the plug is removed from jack J relay 350 is deenergized and has replaced his receiver. In order to'exk plain this fully, .it will be assumed that the plug is removed from jack-J" before'the subscriber at substation Ahashung up. By

the removal of the plug the circuit of relay 20 is broken and this relay is deenergized,

but-' relay 21remainslocked up. The busy lamp L and its multiples are thus kept lighted to indicate that the "trunk is'bu'sy, It will be noticed alsoithat relay 21 main- 1' tains a test potential on the sleeve of jack which permits the usual audible busy test' circuitsto be used in theoperatorsfcord circuits if desired. Now .when the called subscriber hangs up his receiver relays 100 and 101 at the repeater E are deenergized and; theline relay'104; is connected across the incoming trunk conductors as explained heretofore in considering thecontrol'ofthe supervislon. The effect of thls' 1s to energize the slow acting relay 22 which was bridged across the trunk conductors 30 and 31 bythe deenergizationof relay 20. Upon energizing, relay 22 breaks the locking cir-. cuit of relay 21, and this latter relay, 'upon deenergizing, disconnects ;relay,22 from in bridge of the trunk.v Relays 22 and 104 are therefore deenergized.

energized and the connector H is restored by means 7 manner. When the relay 105 at'the re-' peater E deenergizes it removes'ground from the conductor 144, thereby permitting the switching relays and 150 of;selectors D and F. respectively, to deenergize. There upon these switches are restored by means of their respective release magnets and 155 and all the apparatus will have been re-' A by said cut oil relay: ifdisc'onnectlon-is I turned to normal position.

The'description ofrny improved tO11 r;v-

The latter relay breaks the circuit of the slow acting release relay 105 and also breaks the operating cir-. cuitv extending to the connector H; By the latter operation relays 201 and202 are deof release magnet 213 inthe usual ice trunking system is now believed to be complete; "at leastjall the various features which have to dowiththe invention are .be-

lieved to have been covered. It is truethat the operations of the combination toll and regular connector Hwhen used by a local subscriber rather than bya toll operator have not been gone into,but these operations have no especial connection With the present invention, and, besides, they have already been described in certain of my prior fapplications previously referred a), therefore it is believed to be unnecessary to gointogsuch further details rnow.

, l Vhat I claim as my invention: A 1. In a telephone system, a first exchange,

a second exchange, a trunk line having. only V two conductors for connecting SaJdf .ex-: changes and terminating in a ack in 581d first exchange, a cordcircuit for extending a-connection between said exchanges by way of said trunk line, and Ineans operativeif disconnection is effected at said first exchange while the trunk is still held at said second exchange for maintaininga busy po-v tential on said jack untilthe called sub;

scriber replaces his .receiver.

2. Ina telephone system, a a second exchange, a two conductor trunk line connecting said exchanges and terminating ina jack in said first exchange, means for extendinga call from said firstexchange first exchange,

to said second exchange over said trunk line, a

means operative to maintain av busy poten ti'a-l onsaid ack in case disconnection is effected at; said first exchange while thetrunk is'still held at the second exchange, and means controlled over thetalking conductorsfiof said trunk line for removingthe busy potential when disconnection is efieeted at the second exchange. i g 1 i 3. In a telephone system, a first exchange,

a' second exchange, a two conductor trunk 11 "line connecting said" exchanges and "termi nating in a jack in said first exchange, a

I cord circuit "for extending a call from said firstexchange tosaid second exchange over) said trunklin'e, means for placing abusy potential on saidjack'whenthe cord circuit is connected therewith, and a relay operative tonnaintain av busy potential on said jack indefinitely in case disconnection isefl'ected at 'sald' first 'exchangewhile the trunk is still' held at said second exchange. I y

In atelephone syste1n, a first exchange, a second exchange, a trunk line connecting saidexchan'ges' and terminating'in 'a jack in I said first exchange, acordflc rcuit for extending a connect1on' froma'said: first 1 ex: f

change to said second exchange over said trunk 11116,?L'Ctlt off. relay. connected to the sleeve of said ack energized over the sleeve of said cord circuityand means controlled V trun kis, still held at said secondexchange torfplacinga busy potential on the sleeve of saidjack.

5; In a telephone system, a trunk line outgoing from an operators' position, means including said trunk line and a series of automatic switches for extending a connection to acalled line, means for making the trunk P line busy when the operator hrst takes the trunk line'for use, means operated upon the response .of the called subscriber for preventing-the release of said'switc'hes if the operator clears the trunk before the called subscriber hangs up,s'elt locklng'means for maintaining the trunk in busy condition while the release of the switches is held up,

and means operated when the called subsc r iberhangs up for unlocking-said locking means to remove the busyconditlon from the" trunk and y for causing the release of said swltches;

6. In 'a telephone; system, an outgoing trunk line extending from a multiple jack at "an"operators position to an automatic SW1tCl1,2t lamp signal, a lockmgrelay energized when the operator plugs'into said ack to "light said lamp,"other switches, means wherebythe operator can control said first switch and a plurality of said-other switches to extend the connection. to a'called line, means operated upon-the response of the called subscriber whereby the called subscriber assumes control vover therelease of "said switches, a second relay, -means for bridging. said second relay across-the trunk linewhen the operator pulls downt-he con- 'ne'ction, aL-release control circuit completed over said" trunk line and through the second relay'when the called subscriber hangs up, the said second relay being energized to unlock said locking relay, and contacts controlled by said locking relay for breaking said release control circuit'by disconnecting said second relay from in 'bridge'of said switches. means for controlline the operation f '01: said firstselector over the two conductors of said trunk line in series, a line relay in said repeater controlled also over the two conductor-so t said trunk line in series, and flllClllt' connections whereby said line relay controls said other automatic swltches over conductors separate from the talking condoctors." V l i -8. In a telephone system, a toll service trunking system for connecting a to'll'line 1 with alocal 'linefanestablished connection through said system including a two conductor trunk outgoing' from a toll operatorls position, a first selector, a repeater, anda plurality of other automatic switches, a line relay in said selector controlled over the two conductors of said trunk line in series, a line relay in said repeater controllei'l over the two conductors of said trunkline in series after the selector is operated, a line relay in each of said other switcher-i, and circuit connections whereby the repeater line relay controls the line relays or said other switches over conductors separate from the talking circuit. V r

9. In. a telephone system, a toll service trunking system for connecting a toll line with a local line, an established connection through said. system including a two cons" doctor trunk outgoingfrom a toll 'operators positio1i, a ffirst selector, a repeater, and a pluralityvott other automatic switches, a line relay, in said selector controlled over the two conductors of said trunk line in series, a lineire'lay in s a-id repeaterc controlled over the" twoconductors of saidv trunk line in series after the selector is operated, a line relay in each of said other switches, circuit connections whereby the repeater line relay controls the line relays of said other switches over conductors separate from the talking circuit, arelay in said repeater for supplyingtalking current to the'called'local line, and means controlled by said last mentioned relay, for disconnecting said repeater line relay fromsaid' tru'nkline during conversa- 10.1111 a telephone system, a toll service trunking systemifor connecting a toll linev with allocal line, an established connection including an operators cord circuit, a firstselecto r, arepeater, and a plurality of other automatic switches,zline relays in'said first selector and repeater connected vsuccessively in-bridge'of said trunk lineas the connection is established, the selector line relay controlling-the said selector and the repeater line relay controlling the said other switches, a relay in said: repeater operated, on therespouse otthe called subscriber, and means controlled by saidxlastmentioned relay for disconnecting said repeater line relay from the trunk line during conversationf 1-1. In atelephone system, a toll service "trunking; system for connecting a tollaline with a local line, an, established wconnecti on -including-an operators cord. circuit, a first selector, a repeater, and a plurality of other automatic sw1tches,l1ne relays 'insaid first selector-and repeater connected. successively inbridge of said trunk line as the connection isestablished," the selector line relay controllingthe said selector and .the repeater line relay controlling the said other'switches. a relay in said repeater operated onthe response of the called subscriber, means. controlled by said last mentioned relay for dis lee ' connecting said repeater line relay from the same and extinguish said lamp.

trunk line during conversation, and means also controlled by said last mentioned relay for maintaining a local circuitfor'said repeater line relay to prevent the release of the connection. .v i

12. In a telephone system, a toll service trunking system for connecting a toll line with a local line, an established connection including an operators cord circuit, a first selector, a repeater, and a plurality of other automatic switches, line relays in said firsti selector and repeater connected successively in bridge of said trunk line as the connection is established, the selector line relay controlling the said selector and the repeater line relay controlling the said other switches, asignal at the said cord circuit, a supervisory relay in bridge of the cord circuit energized in series with said repeater'line relay. after the connection is established, means in said repeater effective uponthe re sponse of the called'subscriber for disconnecting said repeater line relay froin'the trunk line to deenerg izesaid supervisory relay, and 11162111SWl16I'8bY said supervisory relay controls said signal.

3. In a telephone system, a toll service trunking system for connecting a toll line gized in series with the repeater line relay after the connection is established, said lamp being lighted by said supervisory relay, and means in said repeater for stopping the current flow in said supervisory relay when the called subscriber answers to deenergize the 14. In a telephone system, means for connecting a calling and called line comprising an'operators cord c rcuit, a repeater, a trunk line between the cord circuit and repeater,

and a plurality of automatic switches, a

.line relay in said repeater connect-ed in bridge of said trunk line and controlled thereover for operating said switches, a supervisory lamp at the cord circuit, a supervisory relay at the cord circuit energizedin series with the repeater line relay after the connection is established, said lamp being lighted by said supervisory relay, and means in said repeater for stopping the current flow.

in said supervisory relay when the called subscriber answers to deenergize the same and extinguish said lamp.

. 15. In a telephone system, means for con- 'iiecting a callingjand'called line comprising' an operators cord circuit, :trepeater, a trunk line between the cord circuit and repeater, and a plurality. of automatic switches, a line relay in said repeater con nected in bridge of said trunk line and con-' trolled thercover for operating s aid switclies,

a signal at the'sai-d cord circuit, a-supervisory relay in bridge of the cord circuit en-. ergized in series with said repeater line relay after the connection is established, means in said repeater efiective upon the response of the called subscriber for disconnecting saidrepeater line relay from the trunk line to deenergize said supervisory relay, and

means whereby said supervisory relay controls said signal. I v I 16. In a telephone system, a 'first exchange, a second exchange, a trunk connectj mg said exchanges and terminating in a jack in said first exchange, a visual busy signal, a cord circuit for extending a connection between subscribers of said exchanges by way of said trunk line, and means operative if disconnection is effected at the first exchange while the trunk is stillheld by the subscriber of the second exchange for main taining a busy potential on the sleeve of said jack and for maintaining said visual signal operated.

17. In a telephone system, a first exchange, a second exchange, a trunk connecting said exchanges and terniinating'in the tipand ring elements oi? a jack-at the first exchange, a sleeve element of the jack associated with but not connected tothe trunk, a visual busy signal at the first exchange, means for'extending a connection between said exchanges by way of said trunk line, and means operative if disconnection is ef- 'fected at the first exchange while the trunk is still held at the second exchange for .maintaining a busy potential on the sleeve of said jack and for maintaining said signal operated. a

18. In a telephone system, .a first ex} change, a second exchange, a" trunk connect ing said exchanges and terminating in a jack at the first, exchange, a visual busy signal at the first exchange, a cord circuit for ex tending connections betweensaid exchanges,

means in said trunk responsive upon the con nection being made for causing the operation ofsaid visual sign al, andmeans for maintaining saidv signal operated after the connection has been broken at the. first vexu b said second exchange.

19. In a telephone system, two exchanges, a trunk line terminating in an automatic chan e while the connection is' being held at switch at one exchange and in a jack at theother exchange, a sleeve on said jack elec-j trically disassociated-trom connection 'with' the trunk line, a visual busy signal also electrically disassociated from said trunk: line,

a eord'cireuit for connecting subscribers of 00rd has been disconnected from sairlirunk said exchanges via said trunk iine means in line. i i said. trunk operated When the cord is con In Witness whereof, I hereunto subscribe 10 nected thereto for operating said visual eigmy name this 23rd day of March, A. D. nal and for placing a, busy potential on ihe 1921. v

sleeve of said jaclg andmeans for maintuin- V I ing the visual signal operated after the V r JOHN VVICKS.

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