US1223349A - Telephone system. - Google Patents

Description

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F. W. DUNBAR.

n TELEPHONE SYSTEM.

APPLlcMIoN man umso. 19m.

l* Patented Apr. 17,1917.

q2 Inventor.

17711;@ W `Dunbar/r' B LA y tty.

Witnesses:

F: w. nuNAR,` TELEPHONE SYSTEM ArPLlcATloN HLEIJ necfao. i904. Patented Apr. 17, 1917.

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TELEPHONE SYSTEM. APPLICATION FILED DEC.30 1904 Witnlesses: a. (QJ/ n ,um MM A.

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F. W. DUNBAR; TELEPHONE SYSTEM. APPLlcAlon man nzc.30. 1904 r Fm .w wm., 1. N W D .w.

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UNITED s'rArEs :PTENT FEANCIS'W. DUNBAE, OE CHICAGO, ILLINOIS, As'sICNOE, BY MES NE AssIGNMEN's,-fro

`KELLOoe SWITCHEOAED a; SUPPLY COMPANY, A CORPORATION OE aILLINOIS.

`TELEPHONE SYSTEM.

Specification Of Letters Patent.

To all whom it may concern.'

Be it known that I, FmNc-Is lV. DUNBAR, a citizen of the United tates,` residing at Chicago, in the county of Cook and State ot Illinois, have` invented a certain new and useful Imlin'ovenient in Telephone Systems, of which 'the following is a full, clear., concise, and exact description, reference being had to the accompanying drawings, torming a part of this specification.

My invention. relates to telephone cxchange systems, and has for its object the simplification of operators line equipment present upon the operator-boards,` and also has for its object the provision of improved distribution of the ilistrumentalities employed for uniting' sul'iscribers for converst tion whereby theetiiciency ot the equipment may be greatly increased. My invention is practised by providing answering-jacks (either in the sense such term is used in multiple switch-board practice or in the sense of any jack used with which cord circuit connection is made to answer a calling` subscribcr) for a plurality of telephone lines and selective switching mechanisn'i in circuit relation with the lines whereby these jacks may become connected with calling tele phone lines, whereafter suitable cord con* necting apparatus, such, for example, as 'conmuiuly employs two plugs to each cord outfit, may be used tor uniting a calling'` line with a called subscribers line, the answering; plug` of an operators cord circuit being for the purpose engaged with the jack selectively connected with a calling line, the `linejaclt, preferably permanently connected, ot' thc called line receiving;r the connecting plug.` Reference is here made tomy copending almlication, Serial No. 237,445, tiled ])eccmber 1i), 1904. The present application differs from said (xo-pendingr application by connectingv the selective switches with the answering"jacks. There are con'lparatively yfew answering-jacks as compared with the group of telephone lines with which they are associated and there may he as many cord circuits as there are answeringjacks or` the cord circuits may be son'icwhat in execs.; ot' the number of 'answering-jacks provided to `allow tor inunl'rlnel'it ot' such cords. The jacks are-desirably in the forni oi. sleeves or thimblcs, behind which are vthe cord circuits with calling lines.

fore, use the term answering-jaclts 'and disposed springs tha; Uconstitute the jacks spring jacks and tle elements of the cord circuits that are des gned for engagement with these jacks are `formed into correspond-4 ing plug ever, to the shape oi the jacks nor to the shape ot' the answel ing` .ends of the cord circuits that are maiually applied theretol' For example the ans wering-jacks might in the form of plugs n'iounted upon thefoplerators board and the; answering-,plugs might be inthe form of sleeved elements to` ride over the yansweringljacks, in the form ot plugs, to etiect thi deslredfconneotion of I, thereanswering-plugs in the broad 'snse here indicated, as I do no i wish to be 'limited to the meclianical constfuction of the answer` ing-Jacks. nor to the mechanical construction of the answeringf -ternnnals of the cord circuits manually manipulated by the operi ln `multiple switcl' -board prac-tice 'eyerv. `ciitort has been made to provide room upon, the multiple boards for as many jacks as possible, To this enl the jacks have been placed on three-tent is inch centers verti-A cally and lmrizontally, while the lamps in association with the answering-jacks have -v been placed on centers three-tenths of an inch apart horlzontzlly and one-halfen inch apart vertically. In the present Switchf,

board practice there are from three hundred to tive hundrit answering-jacks and as many line-signals to each' three position section of a multiple Y ioard, which obviously take` up a great deal if room that would be very desirable for lir c-jacks.

1t isoae of the ol'uectsot my invention,

as hitherto stated, torcducc the operators line equipmcut'and l Vaurenabled by means ot :my uwention to du pense `with most ofthe j, answering' jacks and line signals? asjby,l ,in eans ot my inventio 1 thirty jacks, whether of the sleeved or' p ug construction, may

Pate Lited pr, 17,1917.

I do not v .ish to be limited, how- L Y serve yforeach-section of the switchboard and face of the board.

Another object of my inventiony is to simplify mechanical inter-relatlon of the cord circuits and the answering-j acks, which object is accomplished by having the selectwith multiple the lines ing mechanism associated with from left select the jacks in their order, say

to right rather thanpromiscuously, so that the answering-ends of the cords will lead to the answering-jacks in an orderly fashion one after the other, instead of being indiscriminately distributed into association with the answering-jacks of the switchboards according to present practice, for switch-boards now in use the 'mdiscriminate distribution of the answering-ends of the cords is accompanied by an inter-weaving of these cord ends, so that it is diiiicult in effecting disconnection to pick out the connecting ends that mate with the answering ends, which confusion isgreatly lessened, if not altogether dispensed with, by means of my invention.

In accordance with another feature of my invention the lines, the answering-jacks and the selective switching mechanism controlling the association of the answering-jacks with the lines, are so inter-relatedv that the operators at one section -of the board are n fully supplied to their capacity before the operators at an ensuing section are employed, the operators at said ensuing section being fully supplied with work before the indicators and -jacks are 'I erent sections of the loperators at the next section are employed, and so on throughout the system, whereby the "most economical method of operating the exchange is provided. i

In multiple switch-board practice it is well understood by those skilled in; the art that each line has in addition to the multiple jacks distributed throughout the boards of the system, an answering-jack and a line-indicator, the answering-jack and indicator of each line being collocatcd. These distributed in quantity among the difswitch-board, so Vthat there is disposed at all operators positions thesame number of answering-jacks andthe same number of line-siglials. It is, of course, apparent thattelephone operators possess varying degrees of skill and speed in handling calls. The uniform distribution of answering-jacks and line-indicators renders it difficult and impracticable, in accordance with present practice, to apportion work to suit the capacity of the different operators. can properly. attend to two hundred seventy oups of uniform business at board, so as The ordlnary skilled operatory calls in an hour, if the calls be uniformly distributed throughout the sixty -minutes The average time or length of each call is, approximately, one minute twenty seconds, thus allowing each cord circuit to complete forty-five calls per hour, if kept busy throughout the sixty minutes. Six cord circuits kept uniformly busy throughout the hour can, therefore, handle two hundred seventy calls during the hour-the work of the ordinary operator. Certain operators can, however,W handle in a proper manner more than two hundred seventy calls per hour, while others, less skilled, are unable to handle properly as many seventy. I preferably provide means whereby one or more answering-jacks at each operators position may be thrown out of operation or out of operative relation with respect to the lines, whereby each operator .may be given as many answering-jacks in operative relation to the line-circuits as can properly be attended to by'her. Thus, certain operators may have but three or four answering-jacks in operative condition while others, highly skilled, may have eight, nine or even ten answering-jacks placed in operative relation to the lines. By this means each operator may be kept as busy as her degree of skill will permit and paid according to her ability or skill, the number of answering-jacks which she can attend to efficiently being a correct gage or measure of the number of calls which she can handle efiiciently per hour.

It may be properly assumed that oneeighth of the total number of calls made during the entire twenty-four hours ofthe day will occur during the busiest hour. The switch-board must be designed to handle the all hours of the day. Consequently board is determined. by the number ofvoperators required to handle the business during the busiest hour. If duringr this busiest hour or moment, each operator be emanswering jacks and calling signals throughout the various sections of switchto cause as uniform a distribution as possible of the calls during this busiest hour or moment. At best, however, owing to the daily iiuctuations in the amount of business from certain groups and from all classes of lines, it is impossible to distribute the said jacks and calling signals so as to secure more thana rough approximation to a uniform distribution of calls.

By means of my invention, however, a

as two hundredthe number of sections of switch-v i 50% or more distribution of calls may be automatically secured, such that when thenumber of answering-jacks inoperative relation with the calling lines is properly proportioned among and accordingr toy the'slill of the individual operators, each operator vvill be Working at her maximum efficiency not only during the busy hour but at all hours. Consequently the necessary number of sectionsof switch,- board will .be decreased. and fewer operators at all hours of the day will be required.

In all present systems of telephony the calls at all hours of the day are distribuir-edil throughout the entire switch-board, `this re quiring the presence ofone or more opentors at each sectionof the board at all times, save certain of the night hours, when the business i.' so slack that from one yto ten operators-depending upon the size of theexchange-can handle the entire number of calls `by walking from section to section and liiicking up vthevarious calls they may come in. At all such times the efiiciency of the operatorsreckoned on a .basis of num ber of calls answered per hour-is very low, the result being that the average number of calls handled per operator per houx-through` out the twenty-four is less than half the numbl` Which the average operator is able to handle efficiently were she kept uniformly busy. tf',

By means of my invention l amenabled to distribute the calls so `that during the night hoursall the calls will. appear at the first section of the sWitch-board-oi.' at the first two or three-dspending` upon the size of the exchange and. the volume of night business, so. that, as the business increases, operator" after operator ina,y be added as rcquired--thc first or lowerfnumbered sections being always busy and the higher numbered sections coming' graiilually into pperation as the busy l'iours approach. I aml .thus abled.. to secure the same average number of calls answered per operator per hour throughout` the twenty-four as is secured.

during the busiest hour of the day-resulting in a decrease in operating expense of l. do` not contemigiilate, however, in large exchanges providing the neces-` sary switcliinp; facilities, so that each line y may be connected with any one ot all the answering-jacks, altl'lough in smaller switch boards it would he pre'lerable` to do large exiithangcs I prefer to divide the lines into groluis of several hundred each and divid e the a uswering-j a che into a min'lfesl'ionding number of groups, so that any line in a acrtain. group .l'nay` be connected 'with any answe )Hek assigneiil to that griimp, if `the lower. numbered answering-jack of that group'alrea( f be busy. lf that particular one be not hi y, the first :idle answering-jack thus selected, will automatically make connection with a calling subscriber.

For example I will assume an exchange of'four thousan d five hundred lines and pro- `videfa group oE thirty answering-jacks for .eachfive hund red lines, thus .making two `hundred seventy answering-jacksin all, di- ,vided. equally between nine sections of switch-board, fr thirty answering-jacks to the section (inszead of'threehundredrto five hundred as hitherto) and ten tothe opera- "than ythree calling lines simultaneously con nected in conv irsation-in which case the fourth line of thatygroup making a "call While the other three call-ing parties of :the same group We c still connected, would i'ndicate at the fir 4t position of the second section. A fifth c lll from the same group occurring while t 1e other four `Were still convel-sing, would z ppear at the second position of the second section and would necessitate the operator lea vingher position at the first section to atterd toit. Such a condition 90 would not be apt, however, to arise, as it Woul.cl"i'equi1e (assuming one operator only was needed for the business at this time) five`-sixths of tl e total business which this single operator could efficiently handle, to originate in a group containing only oneninth. of the tot: `l number of lines.

.'[nthe `example chosen as an illustration, I would. employ thirty selector switches for each group of ive hundred lines, each `se 100 lector switch including five hundred sets of line terminal contacts.

In the embodiment of my invention herein specifically set forth, the answering-jacks are each provi( ed with a pair of moving 10.5 terminals (the switch-bimrd illustrated being a metallic s vitchboard, the application of the .iilyention to grounded. lines being. well undcrsti'iod by tlose skilled in the art) and motor mechanisn jointly controlled b y the 110 answering-jack :ujn'iaratus anda calling subscribers apparaus for effectingengagement Abetween these terminals,-ivhich l shall call answering-jack terminals and the. terminals of a callin.; line. nism has such-an assoc. 'ation with the answeringjack circuit. and apparatusthat only `the idle answer ugr-jacks areautomatically .prise traveling sivitchearms adapted to pass over terminals cf telephone lines and may, 130

This motor mecha- 115y eration by a calling 1ngjacks. Themotor controlled switching mechanism, which may easily be set `into opsubscriber, 1s so lnterv related with the answering-jack circuits and electro-magnetic mechanism governing the operation of the motor mechanism actuating the answering-jack terminals, that only such answering-jack terminals that are associated with idle answering-jacks are operated by the motor mechanism in mechanical relation therewith. In other words, in the embodiment of the invention herein specifically set forth the calling subscriber causes the motor mechanism associated with the answering-jack terminals of an idle answering-jack to bring said terminals into connection with the terminals of a calling line. Upon such connection of the traveling terminals of an idle answering-jack with a calling line, the lnotor belonging to the answering-jack is caused to stop, preferably by means of electro-magnetic mechanism whose circuit conditions are changed upon this establishmentof connection between an idle answering-jack'and a calling line, such electro-magnetic mechanism thereupon effecting the stoppage ,of the motor, which result is accomplished where the motor is an electric motor, preferably by altering the circuit of said motor. The lmotor controlled switching mechanism governed by a calling subscriber, is preferably common to each group of lines, there being as many such switching meclianismsas there are groups. I'do not wish, however, to be limited to such an arrangement. Where such motor controlled switching mechanism is made kcommon toa group of lines, conductors from all the answering-jack circuits belonging to a particular group are placed in tiontherewith and said switching mechanism is caused to travel over terminals of these conductors. The 'electrical condition of' these terminals kdepends upon the condition of' use ofthe answering-jacks. If the answering-jacks are idle, the electrical character of the terminals is such that when the motor controlled switching device comes into contact with the first of such terminals assoeiatcd with an idle answering-jack, the

.electrodnagnetic mechanism is operated to whereby said answering-jack terminals cor- I responding to the answering-jack motor are electrical associai caused to .engage the terminals of a calling line, whereupon said answering-jack motor is thrown out of action. lVhen the terminals engaged by the motor controlled switching Adevice have their associated answeringjacks busy, the electro-magnetic mechanism immediately governing the operation of the answering-ack motor has no operative effect upon said motor, which thereby remains quiescent. I shall term the motor controlled switching device governed by calling subscribers the subscribers governor motor and the motor which directly operates the answering-jack terminals the. answeringjack motor, as such terms have previously been used.. In order that special line signals will be dispensed with, a signaling device, preferabl7 a signaling lamp, `is associated ywith each answering-jack and suitable governing apparatus whereby it may manifest a signal to the operator when a. calling subscriber initiates a call. A call having been initiated, the operator manually associates the answering endof a cord circuit with the answering-jack of a calling line and manually associates the connecting end of the same cord circuit with a line-jack of the called subscribers'line. This provision of a line-jack to each line to the terminals of each line that are multipled together and are associated with the traveling answering-jack terminals, is an important feature of my invention, inasmuch as by its provision the connecting end of each cord circuit` may in conjunction with its connecting plug, be under the manual control of the operator; The traveling answcring-j ack terminals move over their companion sets of line -terlninal contacts (which latter contacts are, as stated, multipled together) when their corresponding motors are set into operation. Thus, in the example specifically chosen, each line has thirty sets of line lterminal contacts in coperative' relation with the traveling terminals of thirty answering-jacks and each answering-jack has its traveling terminals in coperative relation with five hundred sets of telephone line terminal contacts.

I shall term the conductors th at extend bein addition tween the different groups of lines A and the answering-jack at the second operatorvs po' sition of the first board, the third answeringjack circuit having its answering end connected with the answering-jack at the third operators position of the first board, the

itsl

fourth answering-jack circuit having its answering end connected with the answering-jack at the lirst operators position of the second section of the hoard, the fifth answering-jack circuit having its answering section,` the sixth` answeringjack circuit havingits answering-end connected with the answering-jack at the 'third operators posi# rtion of the' econd section, and so on.

I have indicated ten answering-jacks at each 0];)erators position, and, in order that no operator may receive calls to such an ex tent. that she cannot attend to them, provision is made whereby answering-jack circuits may be made to correspond with busy answering-jack circuits artificially, in order that when a less -eilieient operator has reached her capacity, her answering-jack circuits which havebeen incapacitated will not be connected witha calling line, but, on the other hand, connection will` be effected between saidy calling line and an idle an i11gjacl: circuit at another operator-s position. It will be seen that if each of the thirtv'answerinU-'aclt circuits is worked to.

its maximum efficiency, said circuits will be capable of taking care of torty-five callsl per hour,y or a total oi one tl'iousaml thi'ee hum d red fifty calls during: the busy hour, represei'iting an average of calls` per subscriber during the busy hour, or 21.6 per subscriber per day. Ample margin is thus present for a retfluction in the total number ol. Vansweringjaek circuits in service to an average of seven or eight' per operator, whereby facilities are furnished for handling a greater number of calls per day than will originate in an average exchange of the chosen 1 invention to-.sucl'ipractice.

I will explain my invention more fully by .reference .to th. accompanying drawings illustrating vthe. thereof, in which-n l" igures 1, 2, 3 and 4 illustrate smnewhat fullytelephone exchange systems equipped with 'the al'iparatus of my invention.

Fig. 5 is agi-,neral diagrammatic view illustratil'lg one distribution of the answering-jack circuit: which may be varied to preferred einhmlinlents i suit different exchanges. l

iigures.

Fig. G is a view :llustrating another coni struction of line-jack and answering-plug.

Like parts are in( icated by Similar characters of reference t 1roughout the Adiiferent Each subscriber-s station A-fB :is provided with customary common battery subscribens apparatus, a switch-hook at each station servingl operatively metallically to unite the sides oi the line when the receiver is removed. I do not deemV a detailed description of the subicribers station apparatus to be essential, as the illustration is sufficient to make the` s: une understood by those skilled'in the art. Although I have illustrated one arral'lgenient of subscribers station apparatus,`it will be obvioustothose skilled in the art trat other4 arrangements may be employed -at :he substationgand 'I do not wish to be limited tothe arrangement and l. apparatus shown, mo do I wish to be hunted in all embodiments of the invention. to its application to a ctmmon battery system. The subscribers lines indicated are metallic lines and each extends vin two branches to the exchange, where ;hey terminate in armaturee l-1 of a cutiti' relayQ. The, alternate contacts' of th e armatures constitute terminals of the office end Vof the line which lsupplied with the line-jacks 3 that I have spoken of. The :em illustrated` being a multiple switcl1-boarl system, there are also provided upon othel sectionsefthe hoard than where jack 3 is located, other jacks 4 in connection with ,he said alternate contacts and the oiiice rnd ot the line similar to the connection of jack Multipled terminals 5*:5 and nu ltipled terminals (S-G are provided for each line which are connected with the alternate contacts of the cut-ofiA relay switches and form what I have herein spoken of as the telephone line terminal contacts when the armatures 1`.--1 of said relay are attracted. The contact buttonel or terminals 5--6 are desirably arranged in circular rnvs over which sweep the answering-jack terminals 7-8 and VM-S', which answering-jack terminals are desirabl y not normal ly col'mected. with the answering-jack, but `vhich` as indicated in connection with the terminalsj78, are caused to form contil' nations of the answering-jacl' circuit upon the operation of an arnnlture-switch inch ding a tipv switch con-A tact f) and. a sleeve switch contact l() gov erucd in, `their movement by a relay 11 under oircumstalu'es to i be herelnattcr set forth.

vThere is also an additional circular row of contact buttons 1 2 over which sweep contact arms 1l13 that take part in controlling the` motion li'vthe terminals` 7-8 and 7-8'. The nun ber of contact buttons 5 and also 5', the nun berof contact buttons and also and the nlu'nberof contact buttons l2andxa1so 12', each equalsthe num.-

ber of telephone lines to which a group of answering-Jack circuits hasY been assigned. For example, if thirty. answering-jack circuits have been assigned to a group of five hundred linesJ the contact buttons 5 numberY ing a shaft 14 forming a part of the common prune mover upon which it may be understood the arms 7, 8 and 13 arer mounted. There are thus as many prime movers as there are answering-jack circuits. The

' prime mover 15 illustrated upon the left of each of the drawings is composed of a spring motor 16 in driving engagement with the shaft 14 and a wheelv 17 upon said shaft, -which wheel isprovided with a` plurality of off-set teeth 18-19 arranged in peripheral rows, across which teeth the polarized armagture 20 of the motor is adapted to oscillate by the agency of the field windings 21 and lthe source ofalternating current 22 when said source of current is included in a closed circuit with said windings. The said armature in operating is removed from engagement with one tooth 18 into the path vof an ofi-set tooth 19, whereupon the spring motor may move the wheel a step, whereafter the armature is oscillated to its initial position into the path of a new tooth 18 that is olfsetv'with respect to the previously engaged tooth 19, whereupon the spring motor may move the wheel 17 another step, and so on, until theQ source of current 22 `has the circuit including the same opened.

In the motive device shown upon the right of Figs. 1 and 2, a source of direct current, as the common battery 23, may be employed to operate the'ield winding 2,4, lwhich isV alternately energized and denergized, so that the armature 25 may be attracted from engagement with the teeth in the row 26 and brought into the path of the teeth in the row 27 offset with res )ect to the teeth 26. Upon this attraction o the armature, the circuit through the magnet 24 is opened, whereupon the spring 28 restores the armature to its initial. position. In this way a spring motor, which is assumed to be in driving engagement with the Wheel bearingl the teeth 26-27, may cause the answering-terminals of the answering-jack circuit to move from one line-contact to the next, upon the denergiza'tion of the magnet 24, and as the result of the retraction of the spring 28.

I will explain the circuit arrangements ofYV the magnets 21-22 and the apparatus by which such arrangements are controlled more fully hereinafter. 4

, When a subscriber initiates a call, the answering end of an idle answering-jack circuit, in this case the first, is automatically connected with a set4 of terminal contacts, as the contacts 5 6, for example, this automatic connection being occasioned by the operation of the said answering-jackcircuits motor. Only one answering-)ack circuit motor, that correspondin to an idle answering-jack circuit, is pre erably operated in automatically effecting the movement of the answering-terminals' of said answering-jack into contact with the terminals of a calling line. To' this end I preferably employ selective mechanism, consti-IV tilting an electric motor, that serves to select the answering-jack circuit motor that is to be operated, which selecting motor may be termed the f calling subscribers governor motor and there is preferably only one such motor common to a group of telephone lines. Referring again more'particularly to the systemillustrated in Fig. 1, this governor motor includes in one embodiment of the invention a traveling switch 29 operated by the armature of an electro-magnet 30, as will hereinafter vbe particularly set forth, which switch 29 rides overa series of contact buttons 31, constituting terminals of conductors extending to the various answering-jack circuits of a group, there being as many contacts 31 as there are answering- 100 jacks of a particular lot assigned to a group of lines; there are in the example chosen thirty such contact buttons 31. A complete conductor 32 is shown extending-from one of the contact buttons 31 to the answering- 105 jack circuit that is shown uniting the subscribers stations A and B." Normally, that is, when-its answering-jack circuit is idle, this conductor32 is connected with the grounded battery 23 by way of the switch 110 33 governed by the relay 11. The switch-29 is normally disconnected from ground, but,

vas will hereinafter be more fully set forth,

ture-switch 35, constituting a terminal of 12o.

the generator 22, is attracted to complete the circuit through'the magnet v21 and said generator, the switch 36 controlled by magnet 11, then being upon its grounded contact.

When, therefore, the switch 29 is moved vby a 125 calling subscriber into connection with a conductor that is 'completedat 33, the answering-jack circuit motor of the answering-jack circuit' correspondingto saidV conductor is set into operation. y But where the switch 29 encounters the terminal of a con ductor 32 that is open at 33, as is always the case where the corresponding answering- ]ack clrcuit has been lautomatically con- I nected with a calling dine, said switch is caused to pass said opened conductor and to continue its operation until it encounters ay conductor that is closed at 33 that is, a` place similar to 33. lVhen the switch 29 encounters the terminal of a conductor V,32 that is sociated` with the calling telephone line,y

the magnet 11. becomes energized in a manner more fully hereinafter to be set 'forth, to operate the armature switches- 910, to complete the connection of the answermg-Juclcwith the said line-terminals, to open the conductor at 33, to open the circuit of the answering-jack circuit prime' mover at 36, and to close a subsidiary path through the winding of` magnet 11 to main tain it energized irrespective ot' subsequent changes occurring in the apparatus associated with the calling line, the armatllre switch 37 engaging its contact, which is a pivoted one. before said contact breaks connection with the contact it in turn noclnally engages. As one of the results of these cir-` cuit changes, the answering-jack circuit motor ceases 1ts operation, so that the answering end of the. selected answering-jack cir- `against'.their grounded contacts, 39 being preferablygrounded before 40. The switch 3f) connected with a conductor 4l that is common to all of the lines and which eX- tends to the switch 29 and which is the conductor that is grounded in order to cornplete the circuit containing the conductor 32, when said latter conductor is closed at 33 as heretofore set forth, whereby results that have hitherto been specified are accon'iilished. This salnc conductor 4l has a branch 42 that is connected with the grounded battery` 23, which conductor 42 includes the winding of the motor 30, the switch-arm 43 governed` inits operation by the arma` ture of said motor 30 and thearmature 44 an extension of switch f:

.switch to its normal or initi position.

vwith its Contact, said latter armature belonging .to the relay 45. 'Tl us, the switch 29 '1s not only grounded at 39` but the magnet 30 is included in a ground ed h'cireuit, whicl1 circuit is intermittently op cned `by the separation of the lazy arm 43 from its contact,1 due to the operation of the armature of the magnet 30 and the coperasion of an exten-y sion of said armature beiweenthe bifur-l cated ends of said armi The arm 43 is forced away from its cont actfupon the attraction of the armature ly the magnet 30 and is restored to engagement with its contact by the springin con! ection4 with Said armature, the said armata 'e being thus intern'iittently attracted as l( ng as the circuit i containing the magnet 30 is otherwise closed. Said armature cooperates "vith the teeth of whereby the said switch is caused to tr: `vel as the armature is intermittently attr acted. The dog 46 engages the said teeth t) prevent the restoring spring47 from operating until required, so that the switch 129 is maintained in any position, for the tim c being, in which it has been placed by the inotor 30. When the switch 29 encounters a conductor 32 that is closed at 33, circuit whrough the magnet 45 is obviously closed the winding of this magnet being includel in the 'conductor 41, whereupon the ar. nature 44 is at tracted to bring the` catch 48 into-.connection with the catch upon the dog or detent 4G preparatory (but not at this time in connection with the system siown in Fig.v l) to releasing the said detert from mechanical locking engagement with the switch 29 to permit the spring 47 tc restore the said The c magnet 45 remains energized until the circuit containing the conduc .101*32 is open at 33, which only is accomr lished when the answering-jack circuit mot r selected by the subscribers governor moto: i has brought the answering-contacts ot' its a ;soc`iated answering-jack circuit into conne( tion with calling line terminal contacts. T 1e connection of the answering-jack circuit with the calling telephone line having thus been effected, circuit through the magne.` 45 is opened at 33, whereupon the spring lll lifts the dog or det-ent 4G, permitting the s )ring 47 ,to withdraw or restore the switcl 29 to its initial position. In order that tl e switch 29 may not through some fault in the operation of the apparatus, or in case al 'answering-jacks arebusy, pass all of the co itacts 31 without causing the selection of a 1 answering-jack circuiti and thereafter be not restored, I1" provide a supplemental cintact buttonl50` which is engagedby the brush 29V on reach ing the limit of its excursion, whereupon circuit is completed that m: ty be traced from y the ground at 39 occasioned by `the calling subscriber, the magnet 45, he switch 29g/,the

"minal switch 8, the ground at the cut-off ref lnormally grounded at 56.

contact button 50 and the grounded batter 23, whereupon Athe armature 44 is attracte with the results hitherto specified, the circuit through the magnet 45 is opened at 51 and the springxfl) is permitted to withdraw the detent 46, whereupon the spring 47 restores the switch 29. In order that some of the answering-jack circuits may be rendered inoperative, so that work assigned to less eflicient operators may be reduced, the conductors 32 may each include a switch 52 that may produce a break in said conductor similar to that produced at 33 when the magnet 11 is energized, so that the switch 29 will not pause at a contact terminal of said conductor, but will pass the same as if the answering-jack circuit associated therewith were busy. In order that my invention may ,be effectively practised, the magnet 11 (which is the one that determines the connection of the selected answering-jackvcircuit with the calling t'elephonelline, determines the continuity of the circuit including the governor motor, and controls the electrical character of the butt-ons 31 by controlling the conductors 32 and 33) is referab'ly included in a circuit that is istinct from the talking circuit, which circuit includes a conductor 53 that terminates in the armature-switch 40, there being one such armature-switch 40 and one such conductor 53 for each telephone line. This conductor 53 is connected with the contact but;- tons 12-12, etc., associated with the answering-jack circuits, there being, as hitherto stated,`as many such contacts 12 and as many such-contacts 12, as there are telephone lines in a 'particular group. The switch-arm 13, for example, coperates with the contact buttons 12, the said switch-arm moving with the switch-arms 7-8 until it encounters the conductor 53 that is grounded at 40 by the calling subscriber, whereupon circuit is closed from said ground at 40 through the grounded battery 23 by way of the switch-arm 13, the button 12 engaging the same and the pivoted switch-contact 54 engaging its normal ycontact The magnet 1l is thus energized to bring the switcharms 9-10 into connection with the contacts of the calling-subscribers line, while the armature-switches 33, 36 and 37 are moved by said magnet when thus energized, whereby the said magnet is .included in a circuit containing the battery 23, the contact 54, the switch 37, and the conductor 56 Circuit is also established from the grounded battery 23 through the answering-jack circuit relay 57, the sleeve side of the answering-jack circuit, the armature-switch 10, the answering terlay 2 and also the ground at the relay 58 `that is connected with the tip side of the answering-jack circuit and which ground is met 593.

vthe agency of the plug that brings reached over the subscribers line by way of the answering-terminal 7 and the armatureswitch 9. The operation of relay 57 permits relayll to continuously hold its armatures attracted, since when the armature of relay 57 is attracted, it engages its alternate contact, and when breaking connection 56, 56', completes a maintaining circuit for relay 11, through contact 5 592, attracted armature ofrelay 58, signal 59,relay 89', to ground, the armature of relay 58 bein attracted in time to prevent retraction of t ose of relay 11. The magnet 11 will thus be unresponsive to any change in the position of the switch 40 and the cut-oii' relay 2 will be energized, whereupon the armatures 1-l will be attracted and the switches 39-40 restored to their normal positions, whereby the connection between an idle answering- I jack circuit and a calling line is completely established. Upon such completion of the connection of auseleeted answering-jack circuit and a calling line, the calling indicators 59-60 are operated in a manner to be spe'ci- 'f' fied, whereupon the operator connects the answering-plug 58 of an idle cord circuit with the answering-jack connected with the calling line. This answering-jack may be of the form commonly in use or it may be 'i of the form illustrated in Fig. 6. I do not, therefore, wish to be limited to the construction of the answering-jacks or the construction of the plugs designed for association with the jacks, nor to a plug that is adapted for insertion within the jacks as contra-distinguished from jacks that are adapted to be received by the plugs as indicated in Fig.

A6. I use the term jack, therefore, in the broad sense of a'switch element adapted for association with cord circuits, and have used the term plug in the broad sense of any manually operated switch part belonging to a Cord circuit adapted for engagement with the contacts of the jack. When the plugs are out of engagement with the jacks and an answering-jack has automatically been connected with a calling line,- a part `of the circuit through the calling signal' 59 is made up of the pivoted contact 59I-.engaging the contact `592, the contact 59 being then removed from the grounded con- When the operator engages the answering-plug with the selected answeringjack, circuit through the line-signaling apparatus is broken at 592, but the contact 59 engages the grounded Contact 59 through the contacts 59 and 59" together and thereby separates the contacts 59' and 592. The ground 593 is placed upon the conductor 56 before it is ,removedl at. 592, so that circuit through the magnet 11 will/still remain intact for the purposes that have been specified. After the o )erator'has engaged the answeringplug with an answering-jack, she ascertains jas cuit Ato be 4ve the connection desired, inserts the connecting;` plug companion to the answering-plug into the jacl"-of the called for subscriber, and signalsfftliecalled "for subscriber "with any suitable apparatus; such as that inch'- cated and which is, so well lunderstood.by those skilled in the art as to need-n o including the supervisoryapparatusftl `.t:I have shown is so well understood by ose skilled inj the art that a description thereof would be superfluous. 'lliecirci'iits incliiding and 'controlling calling signals 59-"60 will be'lapparent and need` n'otfbe described.

Iftheca'lling subscriber had restored his telephone before the operator inserted the answering-plug, circuit through magnet 58 would have been opened at the calling subscriber's switch-hook` so `thatcirmitthrough the magnet 11 would hare beenopened at the released armature of magnetS.' After the operator, however, vhas inserted the answering-plug, the control ofthe; magnet 11 is hadl by he' at 59-593. t The' operator when breaking connection between calling and called subscribers, withdrawsthe plugs of the cord circuit to open'f'circuitI through 'magnet 11 at l59' 'and 5933, tliearmat'ure of magnetS beingr then unattracted because of the opening;r m the clrcuitot said magnet o coon the deconnection withj 'a Y toothl 26. his th answerlngiend otttheansaemn g" Sub 1b in ndcs'fsiinlar-armatureiswi 10 SS the anaivering.te-Iim'i'nalfcontA df@- script-ion.` Theentireicord circuit' apparatus A in the left of th( drawing. The magnet 71 operates the arm: ture-switches 9 1() for the same purpose that the magnet 11 operates its alimilture-swit:hes 9-.-10. The magnet 24 is included ina c'1cuit1-that contains the bat- 72 when rnor motor upon the rrangement to that f the drawing, like both governor mocharacters of referparatus and circuits :heirlght (if-Fig'. 1 that have y Qirangeiiients corresponding )arte uponfthe left of the ligure,

y are also glien, similarcharacters of reference.l though in solne cases the mechanical association may not be absolutely identical. After circuit through the conductor has beenclscd upor thfeselcction of an idle an swering-`jack cil cuit switch by the calling subscriber (now speaking of the apparatus upon theright) thejmagnetf is operated to attract armature and complete circuit throughvthe magnet 'Q15 which may be 4traced fr@ 1i tlie1-,gro11n led batteryA through the d contact.- After each attracjiirelfl, circuit through the yut'he separation of the whercbY tl a li'ature'Q is released and is thereuponremofed toa reverse position by the spring 28, w lich spring at the same time causes therestoratione'f the lazy arm toits initial positi' whereupon circuit through the magnet i inst closed, which operation' is vcon lnutd until the answering-jack circuit `n iotor lafs operated the answering ends of the idle .a'lisyeringjack circuit, to bring'- tjhexsaiifie intoj connection with a L'ca-lling subscribers `1lineY terminal contacts. .lVhen thisfresuf t is achieved,V the arm 13 is grounded by way of. the arnniture-switch Vl() of ,the calling s Ibscriber,. whereby the mag'- net 71-isrin`cluo ed in a. circuit that may be traced Yfrom 'he grounded battery 23 throughthe ma guet 24, the armature 35, its

'contactgrpthegmag net 7l', the switch-arm 13, to .thegrounded armature-switch 40, whereby `the arif f magnet i4@ whe reby'the'magnet 71 is ener,

ture '25 remains attracted by.. the

gized. Tiee'norgization of the magnet 7-1 l mental circuit for the a mature 7l of magnet t 71, the armature i lictorv 5G that has a' groun 065 es't'fb ish `'Yt'h'ereupon 'After a. calling` li1 ie l 1 a Selectedjan idle/"answeringvTits I grounded conta ct, "l

rfi

.l energized until' the cord again becomes idle.

Another result of the energization of the magnet 71 is apparent in the denergization of the magnet 34, whereby thegovernor motor may berestored Without the danger of lbeing re-stepped at the end of a connection.

Theprovision of the circuit afforded by the armature contact 75 and the ground 56 upon conductor 56 is for the purpose of maintaining circuit through the winding ol magnets 71j and 24, which otherwise would be broken upon the disconnection of groundfrom the armature-switch upon theoperation of the armature-.switches 9-10 which cause in the manner heretofore set forth, the operation of the cut-off relay and the consequent removal of the armature-suitch 40 from ground.

Should there be two or more subscribers in any group calling at the saine time, it is gp parent that the answering-jack circuit tiareling switch of the first idle answering-jack would select and make connection with the first of the calling lines which the arms 7 8 and 13 encountered and that the switch 29, being then released, would immediately select the neXt idle answering-jack circuit, owing to the ground still present on conductor 41, this operation continuinguntil all of the calling subscribers in a group have been answered.v

A feature of-my invention'resides in. the provision of the supplemental Sets of contacts 1212 in addition to the talking terminals of each telephone line in` conjunction with the switch-arms 13-13 coperating with said contaiixts, all operating in conjunction 'with the answering-jack circuits.

A. very use-inl ieaturc of my invention is the proiisioii ci" .local circuits including subscriberoperated switches, as 40, desirably located at the exchange and adapted to include a switch-arm, as 13, in circuit when placed in engagement with one of the said supplemental line, contacts, 12, vand apparatus included' by said arms in any local circuit thus established, 'which apparatus Will 'serve' to 'effect the restoration of the answer- .ing-jack selecting mechanism, so that said mechanism may be used in perfecting other connections;

/In the precise embodiment of the invenv' tion illustratedthei'e are, as has been stated,

i' se as manysupplemental line contacts l2 and as many supplemental line contacts as there-aire telephone lines. in a particulfn group. There are asmany'sets of ,these con-- tact's12 -'-12 and arms v'1-3--13 as there are an'siy'eisingzjacks assigned torsuoh` group. In

the embodimentof'the inyention illustrated, there are thus maiy more subscriber operfor the local cirf'.

ated switches 4:0 provided spends in function torelay 58. 83-84 correspond in function-to the .lampsl 559-60. The contacts A85--86 cooperate with j connected j in -the cuits than there are sets of contact buttons 12 12 and arms 13--13, but the said arms and contact buttons are adapted to be in eluded. in local circuit with switches 40 of calling lines. I do not wish tol be limited, however, to the precise arrangement illus-v trated. l

The system illustrated in Fig. 2 is similar in general respects to that indicated' in Fig. 1: The system illustrated in Fig. 2 has as a. modification of the system shown in Fig. 1- additional sets of subscribers contacts 76-*76 equali'ng in number the contacts 5-5, 646', etc., the provision of switch-arms` 77-77 for sets of added contacts 76-76" and circuit conductors 7 8--79, in which conductor 78 there is included an auxiliary armature-switch 8() and relay 8l and in which conductor 79 there is included the cut-olf relay 2, the conductor 79 being extended to the multipled spring-jacks, the particular system shown being a multiple switch-'board system, wherebythe cut-olf relay may be operated'froin any section of the board as Well as upon the connection of the answering en`d of an answering-jack circuit with a callingl line. In the system shown in Fig. 1 a side of the talking circuit is, employed in the operation of the relay .2, whereas in the system illustrated in Fig. 2 the-"conduc-- tor that establishes the circuit for the relay 2 is not a section of the talking circuit,

illustrated in Fig. 1, ai'egiven similar ref erence characters. In general, the functions performed by the added conductor are similar to the functionsperformed by one of the talking conductors shown in the system of Fig. 1. The relay 81 corresponds in flinction to the relay 57. The relay82 corre# The lamps'- each otherin opening and closing the cirvcuit -of the magnet 82. The circuit ofV the magnet 82 is iireferably traced from the grounded battery 23 through the winding '82, the contacts SCi-85, the sleeve strand of' the answering-'jack circuit, throughthe subscribei"s line, back to the tip strand o-f said circuit, to the tip line spring andthegrojind.

87 engaging said line-spring when the plug 58 `is withdrawn, soithatthe circuit con-- taining said magnet 87, -Whereby sa id 82 is not only opened4 at 85--86,'but is also opened at the groundl magnet B2 is enti-rely dis= system shown` in'iFig. rather than beingV connected With one iside` the line terminal, as is the cese of'magnet \of the system shown in Fig. 1. Upon the inser ion of the answering-plug 5S within an ans tering-jack, a circuit that is maintained during the presence of such plugin said jack, is established for the magnet 11 and Whichjmay be traced from the grounded battery `through the helix of said magnet, the armature switch 37, the conductor 5G, :to the ground 88 thrown into connection with the contiguous and pivoted contact terminal of said conductoi-.SG by the answering-plug and elements of "the answeringjack operated thereby; this circuit being establislied for the same purpose as that for which circuit was established through magnet 11 of the system shown in Fig. 1 atml, the grounds-88 and 5,93 having-similar functions.' In order that the calling 'signal 83 may positively be disconnected from the line, an auxiliarycircuit opening. and closing switch 89 is provided. 4In each of the systems of Figs. 1 and2 a relay 85) is included in-circuit with the signnls?) and 83, respectively, for operating the auxiliary calling lamps 60 and 84, respectively, whose circuits wi-ll readily be understood by an inspection of the diagrams. iThe cord circuit apparatus illustrated in Fig. 2 including theY answering-plug 58 and connecting plug 61 corresponding to similar plugs of the system of Fig. 1', is well understood by those skilled in .the art and a description of the instru' mentalities comprising the same would be superfinous.v I have indicated in Figs. 1 and-` 2" hose systems that are most commonly employed,.throughout the United States in' large exchanges, the two beingr illustrated in order that `the wide applicability of my inven't'ioninay be readily understood. I do not deem'itessential to illustrate further systems and the application of my invention thereto; U In-thiejsystem illustrated in Figs. 3 and th 'sainefrgeneral systemsY havebeenillus# tra-tedfthnt are shown in Figs. '1 and 2 re-' spectively.

' It W'll have been observed thatthe .mainfunction '-.ofi `the switch Q29 and the elements' in` coipera'tive relation therewith has been 50, performed as soon as an-answering-jack circuit'rnotor corresponding to an idle 'answering-jack circuit has been set into operation. the said-switch 29 being restored to its initial. condition `as soon as the selected answeringjack` circuitl `motor has brought Ythe answering end of .thejansWeIi'ing-jack associated therewitl into connection with the contacts of a call; ine, `soth'at another subscriber i i Switchininitiating another ndicated one sucht switch 2S) eft ofA the draw-ing and another lit i thedrawing for: the purss battiti-,is understood4 that 1only'on`e such Vorgan-ization m. 1

In the system illustrated in Figs. 3- and 4 the subscribe "s governor motor is restored once in a condition to ,be used by another' calling subsc'iber, this arrangement being preferred to 1hat illustrated in Figs. l and 2 in which tile governor motor is thrown out of servic( until the answering-jack circuit motor selected by it has finished its operation in connecting the answering cud of the selected answering-jack circuitwith the line terminal contacts of a callingsubscriher. In the arrangement'illustrated in Figs. fland 4 the answer ing terminal contacts of the answering-jack circuits have initial pt sitions to which the," are restored whentlicir answering-jack circuits are disconnected and placed ou* of service, this arrangement differing from that illustrated 'in Figs. l and 2, Where the traveling answering ends oi" thc answering-jack circuits remain in the positions Where they were last used. By this arrangement it is apparent thatseveral answering-jack .ircuit motors corirsponding to a group of t1 flephone lines may hdsucccssively started before the controlling ground at the switch t!) is removed. It will be apparent that by this apparatus the governor motor common to a plurality of lines -niay be operated in v( ry quick succession as' it is released after s1 arting anI,answering-jack ci rcuit motor without having to be maintained in the positior to which it has-heen actuated by acalling s'ibscriber until the answering-V jack circuitmi tor has effected connection he- 'tween a calliig sl'ibscriber and an idle ansWering-Jack circuit. Several answeringjack circuit nl otors may thus be operating at the same time, therst selected idle an-` swering-jack circuits hav-ing connection eifected with calling lines. That is` the idle answering-jack circuits are connected with calling telephone lines inthe order in which thcyhave been selected by the 'subscribeWs governor motor-,those started by the governor motor in excess of the number calling, which are the last to be started. returning to their normal positions.. Bv thislarrangement the ansiferingends of the answeringjack circuits ii sweeping over the line terminal contacts of a' number of calling subscribers. stop ft thenearest calling'line terminal contacts independently of the answering-jack, circuit .startedby calling subscribers. '.hat is, Vofa` number of calling subscribers in;` i groupv oftelephone lines. one

subscriber may 4causeonei'answering-jack cirl cuit motor to start, ywhich answering-jack circuit motor may eifectconnection of another lower nu nibered calling subscriber with an idle Ia-nswe'ing-jack circuit Referring niw more 'particularly to Fig. 3, .reach sl-ibscribers station, A--B, is prov-ided with the customary common battery subscribers apparatus, a switch-hoch at each station serving operatively metallically to unite the sides of the line when the receiver is-re'moved. I do not deem a detailed description of the subscribers station apparatus'to be essential, as the illustration is suflicient to make the same understood by those skilled in the art, and other arrangements ,may be employed at the jsub-station. As in the fcase of the systen'is shown in Figs. lf'and 2, the system indicated need not be limited to common battery practice. Each si'tbscribers line indicated is a lnctallic'line and extends in two branches to the exclmnge where it terniinates in contact-s 1--1 of a cut-ofi1 relay 22. These contacts are normally engaged by the armatures oi said cuto'' relay and are preferably pivoted contacts and are swung upon their pivots by said armatures when unattraeted, to discontinue, the. telephone line at the contacts 1-1 The upper armature 13 of the relay constitutes avterminal thereof and grounded. The lower arn'iature l4 constitutes a terminal ot the, magnet 38. rThe system illus-,1 trated being-a multiple switch-board tem, the contacts 12 constitute terminals of the ofticeend of the line, which end is supplied with the line-jacks 3and there are also i provided uponother ysectionsof the board than where jack 3 is located,othc r jacks .4 in connection with the 'saidcontacts ift-12. Multiple terminals 5 andmultiple terminals 6 6 are Connected with-the term'fi-l'ials 12-12* and `constitute the telephone Y line terminal contacts, as will be understood.

The' contact buttons or terminals 5 6 are arranged in circular rows over wl'nch sweep the -answering-terminals 7--8 and 7-8,-

which answering terminals are normally connected with the answering-jack associated therewith, but which connection is pref'- erably broken at the armature-switches 9 1() in -thecou'rse .of the selection of an answering-)ack-circuit, so that the apparatus illus- A trat'ed' may be effective for the purpose of 'the "invention, the said armature-switches 9%.'-10 being included in the tip and sleeve sides'of the answering-jack' circuit, respec- Y tively, and being serially included 'in cir- .With the switch-arms 7 8 and the conn" ction/.with said switch-arms. There are alsoprovided the additional rows of contact buttons12 '12 whose general'purpose is s'rnilar to the ,purpose of the correspond- Varg1-ry:

designated contacts of Fig. 1, but whose circuit relations are somewhat modi`v fedjin View of thealtered character of the system of Fig. 3.v The contact or. switch.-

a'rms 13,-13". sweep vover` Contact =buttons 12%12?, these contact. arms being provided forthersame general purpose for which the correspondingly designated contact arms, of

1?--12'when said contacts are in con- Fig. 1 are provided. 'lhesearms are pivoted at the centers of their circular rows oi contacts and are preferably flared or enlarged at their free ends, so that they will ma same time, so that one button willnot be freed from connection with a corres].)ondng arm until, after the succeeding button has been engaged thereby. In the system shown in Fig. 3 it may be understood, for example, that thirty answering-jack'.circuits have been assigned to a group of live hundred lines, that the contact buttons number five hundred, one connected with each line, that the number of contact buttons G equals five hundred, one connected with each line, `and that the number of contact buttons 12 equals live hundred, one for each line. The contact brushes 7, 8 and 13 constitute a set and there are as many sets of Contact brushes as there are answering-jack circuits assigned to a group of telephone lines. Said contactarms of each set are desirably operated by a common prime mover 15; that is, there one prime mov-er provided for each ot said sets, which prime mover may include the shaft 14E upon which said brushes orarms 7, and 13 are mounted, the spring motor 16, the wheel 17 upon shaft'l, the said wheel carrying teeth 18 19, arranged in peripheral rows, across which teeth the polarized armature 20 of the motor is adapted to oscil- -late by the agency of the field-windings .21'

and vthe source of alternatingcurrent 22 when said source of current is" included in' a closed circuit with said windings, this prime mover being similar inits operation to the prime mover illustrated upon the left hand of Fig. 1..

VVhe-n a subscriber initiates a call, the answering end of an idle answering-Jack circuit, 1n thls case 'the first, 1s automatically connected with a. set of .terminal contacts,

i this automatic connection being occasioned by the operation of the said answering-jack circults motor.' In order that the subscribers governor motor nia-y immediately 'be used after causingan answering-jack cir- I cuit motor to start, so'that another answering-jack circuit motor'maybe'4 soon started by another calling subscriber withoutwaiting for the rst 'answering-jack circuit inotor to complete its operation in selectingan (e contact with adjacent buttons at. the

idle answering-jack circuit, the arrangement.

illustrated .isl preferably employed'. "TT-he ..120 governonmotor shown upon the letti-and that' shown opona-the rightech includes a switch 29 operated' .by the armature of an electro-f i magnet 30, as will be .hereinafter more articularly set "forth, which switch 249 rides ,over a. series of' contact buttons 31 constitutingterminals of' conductors extendi'ngto .the

various answering-jack 'circuits of a group,

there being as many contacts 31 las there are answering-jacks ofsa particular lot assigned to a group of lines, ple chosen thirty such contact buttons. A complete conductor 32 is shown extending from.. one of the contact buttons 31 to the answering-jack circuit that is shown uniting the Subscribers stations A-B. Normally, that is; when its answering-jack circuit is idle, this conductor 32' is connected with the grounded battery 23 by way of the switcharm 13 whose normal position is -upon they -this larmature-switch being attracted to effect connectionwith said ground because a circuit is established by said subscriber through the magnet 38 operatings\\'itch 3f) when he removes hisI telephone. for the purpose of making a call,` which'circuit may be traced from the grounded battery 23, through the winding of magnet 38', the armature l, over the subscribers telephone l-ine to 'the contact 12, tothe grounded armature-switph 13. The subscribers goyerno'r inotor includi ing the switch 29, the operating magnet 30 g l5 serving toeattlact 1 gagcthc hook t8 'w1 Vder that the sprm;`

and associated parts, is similar to the subscrlbers governor motor described particu- .larl in connection withFio'. l and a re ieti tion of this description will not, therefore, be required. A callingl subscriber in initiating a call. effects the travel of the switcharni 2f) over the contact buttons 31 until a contact button that is connected wit-h a con# ductor $52 that is associated with an idle'ans\\'ering-jacl{ circuit is encountered, whereupon the motor corresponding to said ans\\"eringjacl circuit is set into operation, 'as

A will he hereinafter set forth. As soon as the answering-jack circuit motor is set into op eration; that 1s, as soon as a vcontauict 31 corres )ondin'f to an idle answcrjnffack circuit b n .l

(inthe case ofthis system the first idle ansuernJg-jack circuit becoming associated with the switch-arm 29) is engaged by the s\\itcl;1-arm or switch 2!) said armis immediately reciprmaited to its initial position because the said switch-arm is pe1flli;l|it .|ltly grounded through the; winding oa magnet l5. circuit through said magnet 4being there forecompleted whena conductor 252,`grouud l ed, aszzhas been specified. at the. battery 2., 1H

connected with the elelnel 4t2!)l tl in"witlulra'wiugthe(v ment 4with the ser there being in the exam- -result is accon circuit Vmay. be t faced vfr switch 29, the circuit established through the magnet by the switch 29 must be open, yso that the sail spring will not be counteracted by the at :raction of said magnet. This plis-hed by the'niovement of the switch-urn.. as 13.. operated by the corresponding ai swering-jack circuit motor from the cont: ct `of the conductor 32 'normadly/engaged bysaid switch-arm, therebydisconnecting the battery 23 from said 75 cond ctor tu `open the circuit including thehiugn-et 45', whereafter the spring 49 may lift the dftent 46 by pulling the'eatch whereupon the switch 29 may be resturedby t he spring +7. after an answringv-jack circuit 'motor'has been started to operate by a governor motor operated by a calling subscriber. the said governor motor is released, permitting it to act without de ay in-starting another an- $5 swering-jack ci lcuit motor in case another subscriber of the group to which the governor motor has leen assigned initiates a call. A supplementa contact is provided so that the switch arm 2!) may be restored in 9c case all the conductors 32 are associated with busy answering-jacks or the switch-arm29 has otherwise tlareled its full course without having stalted an ans\\eringjack circuit Inotor. The contact button 5() is con- 95 nected by way of the switch 51 with the grounded Ybattez-y so that. when the switch 29 engages said button 50;..circuit throughthe mag net 45' willl be completedto draw up the arn ature 44 and effect engage 10g' lnent of the catcrlS with the detent 46, immediately when -after circuit through `the magnet 45, is opi-.ned at 51 so that said magnet 45 is deinergized aud spring 49 is free to lift the detenl 4.6 by the elevationvof the 1.95 catch 48, whereupon the spring/17 reciprocally4 moves` the switch 29. The switch-arm 13 operated b'y t ie selected motor, together with the companion `switch-arms 7 -'8, sweep about' their assoc tacts until the co ltacts corresponding to the calling.,r line are thereby engaged. Prior to the connection ol the talking terminal Icontacts 7-8 at the answering end of an answerinY-'aclc circuit with a callin" sub- 115 h l y r scribers line. the armatare-switcliesll() are attracted bythe magnet -11 through which circuit is at ont-e establi 'l h [m 't battery QSItIn-oug rthewr ndilsr mag 12u net 1 1', to the tl en unattracted armatureswitch il() of magnetl. to the contact button in'eugagement w th the selected conductor 32, to the ground it the magnet 45... Inthe system `illustrated in Fig.3 each ofthe con- 125 t (its. s normal ly' groundedslat tv .f

Thus, directly gc i `ated circular rows of conr11o which occurs when a subscriber first initiates a call, the? ground at 92 being restored as 'soon aS the cut-off rrelay/l2 is ei'iergized` There is thus only'a briet interval in which venting the magnet 11 from becoming enerstored gized when the ground 92 has been re- The energization of magnet 91. is effected by the closure otytlie circuit that may be traced from the grounded batteri7 23,

through the winding of said magnet 91, the sleeve side of the answering-jack circuit, the armature-switch 10,*thc arm S, the winding of the cut-ofi` relay 22, to the ground of said cut-off relay. Upon such energization, the arinature-switch 90 is operated to open the circuit containing the magnet 11. When the magnet 11 is energized, its armature-A switclr is grounded to set the selected answering-jack circuit motor .in operation. Such. energ-ization, as has 'been stated, is efected'iininediately upon the engagement ofthe switch 29 with a. button 31 that is in connection with a switch, such as 13, in cirH cuit with an armatureswitch 90 that is unattracted because of the associ-ation of its operating magnet 91 with an idle answeringjack-circuit. In. this way the selected an sweri'ngljack circuit motorjs started to operate at once when the subsribei"s governor motor has performed its function. said governor motor thereupon beingr released as has been specified. lVhen 'the inagnetll has its 'circuit`ope1ied. the priiiie mover or an i swering-jack eircuitinotor 15 is thrown out of service, as the circuit of the windings 20 is thereupon opened at This opening of the circuit-occurs and is maintained, as hasbeen stated, lby the attractionof the arn'iature-switch '90 which is occasioned Lipoiithe coiinection'of the grounded cut-oli' relay- 2 with the magnet 5l,.wliich latter result is not occasioned until the calling siibscribers line is connected .with an answering jack circuit.

groiindcdciit-otf relay with the winding` of magnet 91. cannot occur until thc switch l() has beenA released bythe magnet 11'. This release yis effected whentlie armatarc-switch 90 included in circuit'with the'inagnet 11 has its associate arm4 1.3 come into contact: with the'but-ton 12 of a calling-line from whihthe ground at 92 is at this particular Obiiously, such connection of the instant removed, the circuit through the winding 11 being thereby opened at 92. This ground 92, as hitherto stated, is restored to the contact 12 engaged by the arin 13 when the c.ut-off relay is included in circuit, but the magnet 91 has in the meantime operated the switch 90 to open the circuit including the winding 1l,. so that the switches 9-0 are permitted now' to remain in their unattracted position during connection, while at the saine time the motor wind ings 21 are caused t0 remain passive because their circuit is opened at 35, whereby the aiiswering-terininals of theausii'ering-jack remain in engagement with the selectediline contacts of a calling subscriber. The call? ingr signal relay 93 is now brought into circuit that is completed byl way of the subscribers switch-hook and which`circuit incliides the grounded battery 23, as will be apparent.l saidv relay thereupon being energized to attract its armature and close. auf other circuit containing the calling lamp 94 and the relay 94 governingr the circuit including the auxiliar) or pilot signal lai'np SH2. The operator in response, to this signal, inserts the answering-plug 58 into .the se; lected ansv.'eiing-jach alid thereby opens at 95 the circuit containing the elements SMWQLL. The operator in. response ,to the signal at 94, ascertains the connection desired and effects connection with the called subscriber in a manner well understood and which need not be described, nor need the cord circuit apparatus, with the aid of which she is able to perform -her Work, be de' scribed, as the apparatus illustrated and lts functions are well understood by those' skilleiliii the art. Prior to the insertion of the answering-plug, the,A calling subscriber may effect a restoration of the motive apparatus associated with the answering ends of the aiis\\'eiiiig-jacl that have been moved into connection with bis line, as `will be understood Aby the descriiition shortly to be given. `After the answering plug has been inserted, howerer, the restoration of the appara-tus is within the control of the operator. In orde-r to effect the. restoration ..0 the traveling ends of the answering-jack circuits, the switches 7,"8 and13 continue in their previoiis, .direction ot' rotation, 'but the polarized armature 20 for this purpose must again be' set into motion, to which 'end ther . magnet 1,1 .must now be. energized to ground I his result 'is accompllshed the switch 35. by the operator on withdrawing the answering-plug 58" by closure of the contacts 95,' the contacts 9G being closed because of the denergization of the magnet 93 occurring iipon, the restoration of the receiver upon the switch-hook at the calling subscribefs station. never been inserted, such energization of the magnet 11', would be occasioned at the con- Correspondingly, if the plug 58 had y tacts 9G, the contacts 05 beine; then closed, the calling subscriber. ot course, having restored his telephone upon its switclrhook. (,ircuit thus established at S15-0o may be 5 traced from the grounded battery 28, to the switch ',r the contacts Sla-M6, the magnet 95. the arinature-switeh 00, to the ground at U2 now present. The armature of magnet 05 is thereupon ittracted. whereupon the 2o grounded catch lllz'engaees the armature oi said magnet 95. whereb)v circuit through magnet 11 is established for the purpose specified. which circuit may be traced .from the grounded catch 102i the armature of magnet 05', the windingotniagnetll, to the grounded battery 23, whereupon the wind ings 21 othe alternatin currentinotor are set into operationcircuitthrough winding 11 being inaintainedfmeeliaiiicallit at 102'7as the arm 13 in being restolf'ed might enconnter the ig'ribunjdless contact Uien the initial po'siti-onsl "e been reached, the pin 103 strikes-an `il lated!finger projecting from the pivoted contact or catch 102, there- 25 by witlnlrawing the said catch from engagement with the arlnatureof magnet 05 to open the circuit ot magnet 11 and thereby cause a cessation ofthe polarized armature. Q0. so that .the switch partsT` 8 and 13 reinitial or no rlnal positions.

i gpfo'nf lthe .lower right similar in .elecine! respects is nst'ru'c'tion from l lhe'ilallns 7. I82 4and 132 correspond in function heal-ins 7, 8 and 13, lult the, former 'a-l y.are designed for rectilineal travel, to which end certain `modifi- 43 cation is required in the prime lnover or answering-jack ,circuit Vmotor that effects the travel of si `d"a`rrns,it`or they n lust be adapted vfor reciprocation instead ot' travel in a continuous direction to effect their .pui-pose.

4a .lhe contatlt 72, 2 and 132 are similar in. function to the contacts provided in association with the arms 7, S-and 13. respectively. There is,

however, a 5G 106 forciilf with th( `answeri'ngjack circuit equipped 'li-1s should tra velt-heir fullest ex- ,ting the Aconnection of a callingfliue, said arm 82 i he restoration `of Y ,A s ini-lar, to that 'the left and similar parts are upon t sh own a. n gagetLb-a'switchtftli-lfmlglihtlle magnet 107 is ircuit may be traccd flgom the `battery 23, through the. winding i' thcialrlnatnre,switch108, the

Vcuit through the winding llpiis o 'n d `operate the arinat llre-switch 11'5- v -niay be restored by the spring 122 n1 edfupon the left ofV buttons associated with the arms additionallnlt `ground contact ma 72, 8? andl, so that in case '523, toithe magnet 101', the parts -1-1- 1i to the ground upon part 117;@Thc .spring l 122 4restores the ausw eringjack circuit motor haracters of reference. When' switcharn1 132, tha conductor 32, theswitcharin 29, to the grnund at magnet' 45" with results'that will V)e understood 'in 'y1 w of the description of the left hand subscribers governor motor. The arlnatureswtchl 109 70 is thereby operated to close circuit ythrough the winding 110 of the motor operating Athe switch-arms 7 2 8L and 132 in a manner that is obvious when thi wayin which theswitch'-V u arm is operatel is understood from the 75 description previously given, and I Vwill not, therefore. describe the` motor operating. ineclwnism except to describe certa-in circuit l changes that occuito change itsoperativccondition. When in answringfjck circuit has been connecte( with a callinggline, cir- 109 similarly to tl le opening offth throughthc windings 20`at`35'; lione tailed description of theI oplei-litio magnet 107 will n'ct be given? -vl'lhye jo tor 111 that includ s the magnet same circuit relations, confie changes in connecnions thatt'h 113 has; therefore, when the scriber has been co nnectc-d with iug-jack circuit, thi` magnet 112 u to close circuit through theinaig,i

connection of the catch 1,16 with 117` so that the sp ringv118 'may said catch .and feifent'the withd detent 117, rso "that the V arms 'i'2 through the in agnel 11-1 may be traced-from the ground thrownrupon the urinatllre 119 upon the' energizition 4of magneti 112, through the winding.,lr of said ina'gxietolll, over a conductor 12) in association w'itlitlie answering-jack circuit selected correspondingto conductor lill, the upper-armatureswitch of magnet 12, to the grounded"battely 23. Vhle the magnet 111 is energized only when the switc hes 72, 82 and-13l are to, be restored, the mag net 112-is energri "d gifm'- V110 n'lediately upon the connection of'a calling line with an answeri rig-jack circuit, whereby the circuit including the magnet 10ft'^ Vis opened, at 10Sto maintain lnagnet'lOTfde energized until disconnection. The engage-` ment of the. parts-116 and 117,4 (occurring los , upon disconnection as above described,)= part 117 being'gounded, circuit through inagfnet 107, willie may4 ,be traced fron, the,` grounded eifccts'the closure` of il, t v ,l

switch-arms when th dog 117is withdrawn. Although such circu t is established-it will now have no control if the winding 110,'cir# 'i j cuit throufrh which winding' .isopec'd at g 115. but tl, switches 9-10 will be' moved to disconnect the. connecting end of thelanswering-jack circuit from the callinglin'e 139 ,izo 4

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