US1391586A - Electric translator - Google Patents

Description

r. M. sLousn. HECTRIC TRANSLATOR. APPLICA TION HLEP JUNE 23, T911- 1,391,586. PatentedSept. 20,1921.

3 SHEETS-SHEET I.

INVENTDH' F. M. SLOUGH.

ELECTRIC TRANSLATOR.

APPLICATION FILED JUNE 23 I917.

1,391,586,. PatenmdSept. 20, 1921.

3 suns-suing.

WWJNTOR UNITED VSTIATEYISTPIATENT OFFICE.

FRANK 1vr. snouen, or ROCHESTER, NEW on'mns'srenon. 'ro'rHE STROMBERG-CARL- son TELEPHONE MANUFACTURING COMPANY, or nocHEs'rER, NEW- YORK, '11

CORPORATION OF NEW YORK.

- ELECTRIC .TRANSLATOR.

Specification of Letters latent P t t t. 1921 Application filed June 23, 1917. Serial No. 176,502.

T 0 all whom it may concern Be it known that L'FRANK a citizen of the United States of America, residing at Rochester, in, the county of Monroe and State of New York, have invented certain new and useful Improvements in Electric Translators, of which the following is a specification. Y My invention relates to a system for controlling the movements of selective switches, such as are commonly used in automatic telephone systems, and more particularly to se-.

lective switches operated by asuccession of current impulses. 1 f 'It is one of the objects of my present invention to. provide means which will control the operation of automatic step-hy-step switches to select a given one of a number of telephone lines by the mere. closure of a multi contact switch, which may be a manual or an automatic switch. This is accomplished in the present instance by providing meanswhereby the closure of such a switch introduces into the electric. circuit of what I term the translator, resistance coils arranged in a definite way with respect to the circuits of the said translator, and each hav ing certain values of ohmicresistance.v f

This and other objects and the features of my invention will be more clearly understood by reference to the following description in which the complete operation of a system embodying the features of my 'invention is described. j

In the accompanying drawings, Figures 1 to 3 inclusive taken together show a com plete circuit connection between a calling station A shown in Fig. 1 and a called station A- shown in F ig. 3, in a system embodying the 1 principles of my invention. The typical automatic telephonesystem represented herein is of the well-known type of system embodying individual or line switches for the stations, selectors and connectors, the connection shown being established through the medium of the line switch C, first selector E, second selector F and connector H. As shown herein, the station A comprises the usual receiver 2 and transmitter 3. I

The means whereby this station A is en'- abled tocall other stations of the system, for instance the station A, are shown in Fig. 1 wherein are shown keys'K K and K of a series of keys, the-others notbeing M. SLOUGH,

shown, each key of which in theembodiment illustrated when operated will close five pa rs of contacts individual to the operated key.' Also in connection with. these keys in Fig. 1 is. illustrated the electric translator system comprising electric circuits and apparatus, the object of which is to translate the several units of resistance included in the circuit of the translator by the operation of the keys just mentioned into the de sired succession ofcurrent impulses to operate the selective switches necessary to be tion A. v I

, The electric translator shown in Fig. 1, comprises relays h, i, y and 76, together with theirassociated controlling relays Z, m, 'n ando to include atthe proper time in the operation of the system, the proper resist- 1 of one of the pairs of contacts of the balance" relay J will operate. the relay a, and the closure of the other pair of contacts of the balance. relay J will. operate the relay 6. Furthermore, the relays a and b have their circuits interlocked so that one of the relays having been operated it remains operated until'after the other relay is fully operated. The circuits of the electromagnets c and d. are arranged to include resistance coils and a source of 'current,'the electromagnet 0 being adapted to contain in its circuit the 'difi'erent reslstance coils of which ever of the keys K K K etc, as may be operated under the control of the controlling relays; and the effect of theelectromagnet 0 upon the armature of the balance relay J is adaptedto be counter-balanced by the effect operated in order to call the desired staof the electromagnet d inthe circuit of which is included variable resistance containing resistance coils 11 to 30 inclusive, of the current impulseoperated stepby-step rheostat L shown in the-upper part of Fig.

1. This contains a plurality of relays, each a capable of short circuiting a resistance unit in the circuit of the electromagnet d of the balance relay J.

An interrupter I is also shown in Fig. 1

' and performs the double function of simul-.

taneously operating the step-bystep rheostat L to decrease the effective resistance of its resistance coil, and also to cause the contacts 31 of the relay f to be operated to produce these contacts are adapted-to be operatedunoperation following: 2 5

der the control of th'e translator of Fig. 1 to produce the same effect as would a dial of the usual automatic station.

' The invention will perhaps be better understood from the detailed description of the Assuming that the operator of thestation A desires to converse with station A, or for any other reason desires to make telephonic connection with the station A, the operator A will remove the receiver 2 from the switchhook' causing the switchhook to close contacts 34 in the'circuit of the line conductors 141 and 142 leading to the line switch C of Fig. 2, establishing a bridge across the line conductors141 and 142 through the receiver and transmitter of the station, and through contacts 31 of the relay f of the translator.

The closure of this bridge across establishes an energizing circuit for the line relay139 of the line switch C. The relay139, upon energizing, operates toclose a circuit of'the operating winding 140 of the magnet 220,

which upon energizing, attracts the plunger arm 207 and cutoff armature 206, whereby the line conductors 141 and 142 are extended through the line'switch bank springs 143 and 144, and 145 and 146 to the selector E,

and the line relay 139 is disconnected from the line. .WVhen the connection is extended to the selector E its line relay 147, which'is normally bridged across the line circuit of the switch in serieswith the battery, becomes energized and operates to close the circuit of the relay 148. The relay 148, upon energizing, operates to close the circuit of the holding winding 149 of the line switch C before the line relay 139 breaks the circuit of the operating winding140, and'to extend a guarding'ground potential over the conductor 150 to the connector private bank contacts of the calling line, upon which is located the station A. The apparatus ofthe first selector hl'is now adapted to be operated by the opening and closing of. contacts 31 of the relay f underthe control of the transla- We will assume that the operator desiring to call a certain number consisting of four digits, operates the key K closing contacts 35, 36, 37, 38 and.39. Theclosing ofthe contacts 35 will cause ,a circuit to be closed, in-

fcluding the source of current G, the conductor 45, the winding of the relay 6, the conductor 46, and the contacts 35 to the ground pole of the source of current G. Current flowing over this circuit from the source G will energize the relay 6, causing it to attract its armatures for purposes laterto be dc scribed.

Up to this time the retractile spring 47 attached to one'side of the armature 48 of the balance relay J has caused it to close con tacts 49. 7

When the relay 6 is operated a circuit is closed including the winding of the relay a which may betraced as follows :'from the ground pole of battery, the armature 48 of the balance relay J, the normally closed contacts 49 thereof, circuit conductor 50, the

winding of the relay a, circuit conductor 51, circuit conductor 52, and the now closed con-;

tacts 53 of the relay e to the negative pole ofbattery G.' The relay (1 will therefor be energized, attracting its armatures, aflec'ting circuits to be'later described.

The contacts 44 of the relay 0 being closed, complete a circuit for the winding of the electromagnet d traced as follows ':from the negative pole of'the source of battery G, circuit conductor 41, the winding of the electromagnet d, circuit conductor-42, theiresistance units 11 to 30 inclusive serially connected by conductors extending between them, to circuit conductor 43, circuit conductor 54, and the contacts 44 of the relay 6' to the ground pole of battery. The electromagnet d will be energized to a degree which depends'upon the amount of resistance contamed 1n the circuit of its winding, and

, which contains resistance unitsll to 30 inclusive. The effect of this energization would be to keep closed the contacts 49 of the balance relay J were it not for theother circuit changes which will now be related. Also-the relay at having beenienergized as before described, attracts its armatures operating contacts and causingcircuit changes as follows. The contacts 60' will be broken,

and the breaking of these contactswill' have no effect-upon the circuits as constituted at this stage of the operation. V Contacts 61 willbe closedforming a looking circuit for the. relay at including contacts 62 of the relay b as follows :from the ground poleof'battery, contacts 62 of the relay 2;, contacts 61of the relay a, the Wind ing of the relay a, circuit conductors 51-and 52, and contacts 53 of the relay 6 to the negative pole of battery G. This locking circuit will maintain for the moment the 65 tor to produce results later to bedescribed. relay a operated even though the contacts 49 may bebroken, or until the'contacts 59 of the balance relay J are closed as will be later described. The contacts 63 'of'the relay a, will also be closed completing a circuit for the slow releasing relayg as follows from the ground pole of battery, the source of battery G, circuit conductor 64, the winding of the electromagnet g, circuit conductor 65, and now made contacts 63 of the relay a to the ground pole. of battery. This will cause current to flo-wover the circuit and en. ergize the relay g, which will attract its armatures breaking the pairs of contacts 66 and 67" which at this stage of the operation will have no'positive effect upon the circuits. The contacts 68 of the relay a will also be broken, and will have no positive effect at this stage of'the operation. Likewise the contacts 69 of the relay 0; will be broken, the

breaking of these contacts having no positive effect at this stage of the operation.

It will beseen later that the relays aand (Z ar operated a number of times at different stages of the operation of the system, and that on subsequent operations the contacts which have been impotently operated at the present time will be effective to control circuit changes.

. At the time the relay e was operated,also

the contacts 40 were closed completing a circuit including the winding of the electromagnet c and the resistance coil 54' over a circuit as follows :--from the ground pole of battery, the source of current G conductor 55,'the now closed contacts 40 of the relay 6, circuit'conduct rf 56, the normally closed contacts 57 of therelay h, circuit conductor 58, contacts 36 of; the key K and the resistance coil 54 to the ground pole of battery. Curr nt will flow over this circuit including the winding of the electromagnet c, and will energize the electromagnet a to a degree depending upon the resistance of the coil 54. The first resistance coil of each resistance coil 54 being the first of the group included in the circuitiby the operation of thekey K indicates in which tens of thousands group the connector of the, called-for line resides. life will assume that the ohmic resistance of the resistance unit 54 is such that it represents vthe'digit 5, andtherefore in order to produce the desired result it will cause the calling interrupter contacts 31 to be opened five times, which it will now do in a manner to be described.

The electromagnet cbeing energized over the circuit just described will close contacts 59' of the balance relay J overpowering the effect of .the electromagnet d, for-the time being. Thecondu-ctor' 59 being closed will complete a circuit for the relay 1) traced as follows :-from the round pole of battery, the armature 48 of t e balance relay J, contacts 59 thereof, circuit conductor 70, the

winding of the relay Z), circuit conductor 52,

and the now closed contacts 53 of the relay 6 through the source of current G to ground.

lurrent flowing over this circuit will cause the energization of the relay 5, operating closed contacts '66 and 67 to normal positions of closure. e

A locking circuit for the relay 5 will be formed by the closing of contacts 71 of the relay b,.'the locking circuit being traced as follows :'from the ground pole of battery, the now closed contacts of 'the relay 5, the normally now closed contacts 60 of the relay a, the winding of the relay 5, circuit conductor 52, now closed contacts 53 of the relay '6 to the source of current G to the ground pole of the said source. This circuit will maintainv energized therelay b whether or not the contacts 59 should be opened or previou'sly opened, and until contacts 49 are closed as will be later described to break thisv locking circuit.

The contacts. 74 of the relay 1) will be closed completinga circuit for the relay l. as follows :-from the ground pole of battery, the contacts 74 of the relay circuit conductor 75, the normally closed contacts 68 of the relay (1, the normally closed contacts 76 of the relay h, conductor 77, relay Z,-circuit conductor78, circuit conductors 51 and 52, the now closed contacts53 of the'relay e, and the source of current G to the ground pole of battery, Current from the said source will flow over this traced circuit energizing the relay Z, which will close its contacts 79 conditioning a circuit for the relay h, but which circuit will not now be operative to energize the relay it, due to thefact that the ground pole of battery is applied on both sides of the winding-of the relay 71,, thereby short circuiting this. relay. The

contacts 73"of the relay 5 are also closed completing a circuit including the interrupter I and source of current, and the winding of the relay f, said circuit being traced as follows :-from the ground pole of battery, the

source of current, the interrupter I whose tion thereof normally closed contacts 69 of the relay a, circuit conductor 84, and the now closed contacts 7 3 to the of battery. v

The circuit of the relay f thus being closed through the interrupter I, the relay 7 will be operated as long as this circuit remains closed intermittently each operation causing a momentary opening of the contacts 31, which will cause circuit changes to be later related. Also each operation of the relay 7 will cause a momentary closure of the .contacts 85, completing a circuit for successive relays of What I have termed the electrical current impulse operated rheostat L. The effective first circuit closure between the revolving segment and the brush 81 produces the first opening of the, contacts 31, and also the first closing of the contacts 85, which latter closure will complete a circuit traced as follows :from the ground pole of battery, the now closed contacts 85 of the relay f, circuit conductor 86 which conductor may be termed the impulse wire, the now closed contacts 87 of the relay 88, circuit conductor 89, the winding of the relay 90, circuit conductor 91, the normally closed contacts 66 of the relay 9, circuit conductors.

51 and 52, the now closed contacts 53 of the relay 0, and the source of current G, to the ground pole of battery. Current will flow over this circuit through the relay 90 operating the relay 90, and closing contacts 92 and 93. Theclosure of contacts 92 will condition a circuit for the relay 88, but this circuit will not at present be operative to energize the relay 88, because of the short cir-- cuit'now introduced about the winding of the relay 88 by the placing-of a connection to ground on each side of the winding, by

the contacts 85 of the relay f on theone side,

and by the contacts 92 over circuit conductor 94 on the other side; 7

Contacts 93 upon being closed will" short circuit the resistance unit 21 serially connected in circuit with the electromagnet d of the balance relay J, and the short circuiting of this resistance in the circuit of the electromagnet (l will increase the energizaa definite predetermined amount. However, under'the assumptions we havemade, the ene'rgization will not be sufficiently increased' in the electromagnet d to close its contacts 749'. Therefore, at this time no consequent circuit change will be instituted. J a V V The interrupter I continuing to revolve will cause a breaking of the circuit between the segment 80 thereof and the brush 81, and therefore will cause the circuit of the relay f to be interrupted. and a deenergization of the relay will ensue; the relay restoring its contacts to their normal position, the contacts 31 being restored toa ground pole of the source I the contacts 31' will not now be-described,"

but itcwill be understood that the contacts closed condition, and the contacts 85 being restored to their normal position. 1

The circuit changes due to the reolosmg of 31 are operating as would the usual calling dial ofan automatic telephone; and that such circuit changes as would be produced in anpautomatic systemby the usual calling dial will be produced by the contacts-31 as will be therefore related later.

The release of the contacts 85 willyremove the ground which has'been described asbeing placed about the one side of the relay 88, and the energizing circuit of the relay 88 will-be operative, the circuit being traced as follows F-from the ground pole of battery, conductor 94, contacts 92 of the relay 90, the windingof therelay 88, circuit con- 7 ductor 89, thewinding ofthe relay 90, cirf cuit conductor '91, the normally'closed contacts 66 of the relay g, circuit conductor 51, circuit conductor 52, now closed contacts 53 of the relay 6, and source of current G to the ground pole of battery. The relays 88 and 90 are thus operated, their windings being serially connected with'the source of current. The relay 88 being operated will attract its armatures, operating contactsas follows :-contacts 87 will now loe broken a interrupting the circuit of-the impulse wire 86, the impulse wire extending by means of the now closed contacts 100 to operative connection with the relay 95 through conductor 96, the normally closed contacts" 97- of the relay 98, and circuit conductor 99.

' The contacts'501 of the relay 88 will now be closed short circuiting the'resistance unit 20 in the circuit of the electromagnet d of the balance relay J thereby increasing the energization of this relay a definite "predetermined amount. "Under our present assumptions however,rit-is arranged that this energization shall not be sufficiently in creased at this time to cause the electromagnet "03 to close the contacts 49.

The interrupter I continuingits rotary movement will again close a circuit-between its segmentSO and'its brush 81, and complete afcircuit for the'relay '95 as follows mally made contacts 67 of the relay'g,'-the' 31, and again close contacts 85, this being the second operation of these contacts.

circuit the resistance unit 19 in the circuit of theelectromagnet d, thereby increasmg The contacts 85 being again closed will. complete a circuit over the impulse wire'86, whichas has been described is now extended; by conductor 96, contacts 97, the conductor 99 tothewinding of the relay 95, and v battery at either side of the winding by the I contacts 85 of the relay f on the one side, and by the circuit conductor 94 and con tacts 502' on the other side. I H

The contacts 503 beingoperated will short circuit a resistance unit 22in the circuit of the electromagnet d, thereby increasing the energization of this electromagnet a definite contacts 510 and 511. The contacts 510 being closed will condition a circuit for the predetermined amount, but under our assumptions msufficlent to cause 1t to close the contacts 49.

The interrupter I continuing to rotate will now break the connection between its segment 80 and the brush 81 in'the circuit of the relay 7, thereby again restoring the contacts of the relay 7 to normal the contacts 31 thereforebeing again closed, and

the contacts being therefore again opened. The contacts 85 being'again opened will' remove the short circuited ground connection from about the one side of the winding of the relay-98, and'will permit the relay 9810 be energized over a circuit as follows fro1'n the ground pole of battery, conductor 94, contacts 502 of the relay 95, the winding of the-relay 98, conductor 99, ther winding of the relay 95, circuit conductor 91, normally closed contacts 66 of the relay g, circuit conductors 51 and 52; now

closed contacts 53 of the relay 6, and the source of current Gr to the ground of the said source. Current will flow over this circuit energizing the relay 98 which will at-;

tract 4 its armatures operating contacts as follows: .7

Contacts 97 will be operated interrupting the circuit of the impulse wire 86 as extend- .ed by the" conductor 96, and will again extend it by means of contacts 504, and conductors 504and 505 tothe winding of the relay 506, through the normally made contacts 507 of-the relay .508, and'circuit conf ductor 509..

The contacts 510 being closed will short the energization of the electromagnet d a definitepredetermined amount, but. which amount according, to our present assumptions will be insufiicient to cause it to close contacts 49. 7 I r The interrupter I continuing to rotate will again cause a connection to be made between its segment 80 and its brush 81 again completing the energizing 'circuit'of the relay 7 which as has been previously described energizes the relay f which will attract its armatures, and for the third time opening contacts 53 of the relay 6, and the source of r current G to the ground pole of said source.

This circuit being completed current will flow over thesameenergizing therelay' '506 which will attract its armatures and close winding of the relay 508, which circuit will be at present impotent to operate the relay 1508, because of short circuiting ground being placed about the winding of the relay 508 in amanner like that described for the relays 98' and 88 in the like stage of their operation. v Contacts 511 being closed will shortcircuit resistance unit 23 in the circuit of the electr'omagnet 01, thereby increasing the energ'ization of this electromagnet a definite predetermined amount, and which amount under our present, assumptions will be insufiicientto' cause it to close the contacts 45 of the balancerelay J.

The interrupter I continuing to revolve will cause itssegment and brush toseparate opening the circuit of the relay 7 which will restore its contacts to their normal position, contacts 31 being restored to their normal closing position and, the contacts being restored to their normal opened p osition. Contacts 85 being openedwill remove the short circuiting ground from the 1 one side of the winding of the relay 508, and the relay 508 will be operated over a circuit including the winding of its associated relay 506, said circuit otherwise being like unto that of the relays 98 and 88,

and which circuits have been previously so well described it is believed unnecessary to describe it, particularly for the relay 508. The. relay 508 being operated will operate itscontacts Contacts 507 being broken the impulse wire 86 as extended 'by conductors 96 and'505 will be again extended by contacts 512'and conductor 513 to'the winding of the relay 514 over contacts 515 of the relay and circuit conductor 517. The contacts 518 of the relay 508 being closed Wlll short circuit the resistance unit 18 in the circuit 'ofthe electromagnet d and will encrgizevthe electromagnet d a definite predetermined amount, but which increased energization according to our present assump- Vtions, will be insufficient to close contacts 45.

wire as extended as described, and the relay 7 514will be operated closing its contacts 519 and 520; The contacts 519 being closed'will condition. a circuit for the relay 516, said circuit being at present inoperative because of the short circuiting connections to ground on either side of its winding. The contacts520 being closed will short circuit "the resistance :unit 24 in the circuit of the electromagnet d, and therefore the energination of this electromagnet Wlll be again 1n-' creased a definite predetermined amount,

but which amount will be insufiicient according to our present premises to cause the electromagnet d to close the contacts 49 of the balance relay J. g

- The-interrupter I continuing to revolve will again cause its segment 80 to break connection with its brush and thereby cause the breaking of the circuit of the relay fre- .storing its contacts to their normal position,

contacts 31 being restored to a closed position, and the contacts 85being restored to an opened position. The opening of'the contacts 85 will remove the ground on one side of the winding of the relay 516 and the rela 516'Will be operated, the circuit of this windingv including the serially connected winding of the relay 514 but which circuit need not now be traced it being like unto the-circuit of the relay 508, also of the relays 98' and 88 which circuits have been previously well described. a v .r I

The relay 516 being operated will operate its'contacts, the contacts of the relay 516 connecting the extended impulse wire to the relay 514 being broken, and the impulse wire, 86 as extended'by conductors 96, 505 and, 513 will again be extended by contacts 521 and conductor 522'to the winding of the relay 523 over contacts 524 of the relay 525 and circuit conductor 526. The contacts 527 'short cireuit about the resistance unit 17 in the circuit of the electromagnet cl, and the electromagnetd will have its energization ohmic resistance of the resistance unit 17, but the increased energization of the electromagnet d will not besufiicient according to our present premises to cause it to close I j the contacts 49 of thebalance relay J.

The interrupter I continuing to revolve will again cause its segment'80 to make contact with its brush 81 again reeestablishing the circuit of the relay f, and forthe fifth time will separate its contacts 31 and will close its contacts 85. The contacts 85 being closed will reestablish the ground connection to the impulse wire 86 which is now connected in circuit with the winding of the relay 523 bythe extended circuit of the said '80 impulse wire as previously described, and

Contacts 529 being closed will short circuit l the resistance unit 25 which is included in the circuit of the electromagnet d ofthe balance relay'J, and will therefore increase the flow of current through the balanced increasing its energization a definite predetermmed amount, the increased energizatlon,

depending upon the particular predetermined value of ohmic resistancein the resistance coil 25! p 7 Under our present premises we w ll 'assume that the short circuiting of thisres'istance unit'in addition to the short circuiting of resistance units 17, 18, 19, 20, 21, 22, 23 and 24, all in the circuit ofthebalance relay (Z, produces an aggregate increased current flow through and thereby increased the energization of the electromagnet cl 'suflicient' to cause the balance relay d to' overcome the effect of the electromagnet c and to withdraw the armature from the position of proximity to the pole of electromagnet c, and to cause the armature to close the con-' tacts 49 of the balance relay J. The closing of the contacts 49 as will be seensignifies the endingof the first train of current impulses instituted by the opening and closing of the contacts 31, which contacts'as has been seen have been" opened five times in rapid succession. J

The contacts 49 of the balance relay J g now being closed complete a circuit includ- .of the ,relay1516be1ng closed will establish a ingthe winding ofthe relay a, the circuit being traced as follows from the ground pole of battery, nowlc'losed contacts 49 of the balance relay J \circuitc'onductor 5 0, the

winding of the'relay a, conductor" 51, com ductor 52, the now closed contacts 53 of the relay- 6, and the source of'current G to the ground pole of battery. i.

Relay a willnow be energized attracting its 'armatures, switching contacts for purposes which will'now be described. The contacts 60 of the relay a'will be broken interrupting the locking circuit of the relay 6, and the relay 5 will therefore be decnergized restoring its contacts to their normal position. The contacts'61 will now be closed and will complete a locking circult for the relay at, including the contacts 62 of the relay -b which are now restored to their normal position ofclosure; This locking circuit has been previously described, and therefore the description will not need to be repeated.

Contacts 63 of the relay a, will also be 3 closed, closing the circuit of the relay 9 which relay is a slow releasing'relay, and the relay 9 will be energized over this circuit which-extends fromthe source of current Gthrough the winding of the relay g,

the conductor and the contacts 63 of the relay a to the ground pole of the source, and will attract its armatures breaking the contact 66 and the contact 67, the contacts 66 interrupting the common battery conductor 91 supplying connection tothe negative pole ofbattery for the windings of the relays of the electrically operated rheostat L, and these relays which have been operated as has been described including the relays 88, 90, 98, 9,5, 508, 506, 516, 514 and 523 will'all be restored to their normalor deenergized con-' dition, restoring all of :the contacts controlled therebyto their normal position.

The. contacts 67 of the relay g' being broken will interruptthe circuit of the interrupter I and the impulse relay f, so that the relay f will cease to operate under. the control of the interrupter I, and contacts 31 of the relay will be restored to their normal position of closure, and the contacts will'be restored to their normally'opened position.

The'contacts 68 of the relay a upon being.

broken-will removethe short circuit which had been placed about the relay 7?, by the contacts "(9 ofthe relay Z,- and the contacts- 74 of'the relay 6 and'the relay it will thereupon be operated over a circuit traced as follows :-from the ground pole of battery, contacts 79 of the relay Z, the winding of the relay h, the circuit conductor 77, the Winding of the relay Z, circuit conductors 78, 51 and 52, the contacts 53, and the source of current G to the ground pole thereof. Current'from the saidsource will flow over the contacts 530 and 531 which will-be closedfor purposes to be described. I

said circuit through-the winding of the relay h energizing this relay which will attract its armatures, operating its contacts 7 6 and 57 which contacts will be broken, and operating The contacts 68 of the relay a are preferably given such an adjustment asfto' cause The contacts 59 but slowly. V I Contacts 69 of their opening prior to the operation of the rest of the contacts of the relay a whenthe relay a is operated;

-m'agnet c,circuit conductor 55, contacts 40. of the relay 6, circuit conductor 56, the now made contacts 531 of the relay h, circuit conductor 533, the normally made contacts 534 of the relay 6, circuit conductor 535, the

contacts 37 ofthe key K and resistance unit 532 to the ground pole 0f battery. Current flowing over circuitlincluding the said resistance coilwill be of such a strength as to cause the contacts 49 of the balance be again closed;

being closed will complete the above described circuit for the relay 6 including the said contacts 59 of the balance relay J, and the relay 6 Will be operated as before, and'asabove will release the relay a which in turn will release the relay g. The release of the relay w is caused by thebreakingiof the contacts 62 in the locking circuit thereof previously described,

and the release ofjthe relay 9 isaccomplished by the breaking of the contacts 63 of therelay a. The other contacts of the relays a4 and g, as well as the now operated relay '7), will be operated as will be now related. The relaysaand g are slow releas- 'relay' J to be opened, and the contacts 59 to ing relays, and take a relativ ely longtime to restore their contacts to normal afterthe relays have been once energized, and there 7 fore these relays will restoretheir contacts the relay a and 67 of the relay 9, and the closurefof'the contacts 7 3 of the relay b again places the impulse relay f under the controlof the interrupter I over the circuit which has previously been traced forithis interrupter and relay,and the'relay fwill again be operated intermittently by the relay i until a balanced conditionof the relay J again occurs as will be described. 7

The contacts 66 of the relay gbeing closed will again restore 'the connection from the negative pole ofbattery to the re-' laysof the electrically operated rheostat L.

by means of the conductor 91 whose circuit has been previously described, and these relays will therefore again be conditioned for operation. T

Theclosure of the contacts 74 of the relay b, and the: closure of the contacts 68 of therelay a'completes a circuit for the relay m, the circuit being traced as follows from the ground pole of battery, contacts 7 4 contacts 536 of the relay 2', the winding of the relay m, circuit conductor 78, circuit conductors 51 and 52', the closed contacts 53 of the relay 6 to the source of. current G, and from thence to the ground pole of the said source. The relay m will be operated by current flowing over the circuit just traced, and will close its contacts 537 conditioning a circuit for the operation of the relay 6, but which-relaylwill not now be operated due to the presence of the short circuited ground connection on the opposite side ofthe relay 2', from the contacts 537 through the contacts 74 of the relay 1). These circuits are now'in condition to translate the value of the second resistance unit included in circuit of the key K namely,

the resistance unit .532 into the corresponding numberof impulses, which in'the present case we will assume to be but one impulse, or in other words, that the second digit of the called-for number is to be the numeral l. I

.The relays a and 91 being slow releasing, as has been said, have caused the contacts 31 of the impulse sending circuit to be closed for a relatively long time, thereby performing a. circuit changing function required in the operation of automatic apparatus as illustrated in, Figs. 2 and 3 asvwill be subsequently related. 'i i The interrupter I now revolving will cause contact to be made between its segment 80 and'its brush 81, closing-a circuit including a source of current and the winding of the relay f which circuit has previously been traced, and Will cause the operation of therelay f, which being operated will attract its armatures breaking the contacts 31 in the impulse sending circuit of the station J A," and closing the contacts 85, thereby connecting the ground pole of battery to the impulse wire 86 leading to the electrically operated step-by-step rheostat L;and just as was the case as previously described in the -first operation of this rheostat the relay 90 will first beoperated over a circuit'traced as follows :.-from,the groundpole of battery,

contacts 85' of the relay f, circuit conductor.

7 '86, contacts87 of the relay :88, circuit conductor 89, the winding of therelay 90, and the circuit conductor 91 to the negative pole of battery through contacts66 of the relay g, circuit'conductors 51 and 52, and contacts *firstnzimed contacts conditioning a circuit for the relay 88. justas in the before de-' scribed case, and the second pair of con tacts short circuiting the resistance unit 21.

-- '53 of the relay 6. Current flowing over this circuit will cause the'operation of the relay 90, and willclose its contacts 92 and 93; the

We will assume that the consequent. current flowing over the circuit of the electrQ- and brush 81 restoring the relay f to itsv normal deenergized condition, whereupon the contacts 31 will be restored to their normal position, and the contacts 83. will be opened. This Will cause the operation of the relay 88 in series with the relay 90 as vI before described after theprevious opera.- tion of these relays, and as before described the resistance unit 20 will be short circuited by contacts 501 of the relay '88 and thus. cause a sufficiently increased flow of current over the circuit including the un-short-circulted resistance units of the group 11 to 30 inclusive to cause a sufficient energization of the electromagnet (Z to take place and cause it to close the contacts 49 ofsthe' balance relay J.

From now on the operation of the relays mentioned will be as before described after the sending of thefirst train of impulses,

the relay i'being' previously operated just as was the relay h followed 'by an operation of the relay a just as was the case ofthe relay m previously described, and the resistance coil' 538 will next be included in circuit with. the electromagnet 0 instead of the resistance c0il532, and after a relatively long closure of the contacts 31. The

circuits have been sufficiently described in connection with other previous operations that it is believed unnecessary to again re- I peatthis operation.

The resistance unit 538 is subsequentlyincluded in circuit with the electromagnet 0, the circuit being traced through contacts 539 of the controlling relay y','circuit conductor 540, now closed contacts 541 of the relay" i, circuitconductor 533, now closed contacts 531 ofthe relay h, circuit conductor. 56, now closedcontacts40 of the-relay e, the wlnding of the electromagnet c, and'the' source of current G to the ground pole of said source.

The connection of this resistance unit we will assume controls the operation of the impulse sending. relay f so as tocause two operations of this relay, and therefore two openings of the contacts 31 inthe impulse sending circuit of the station 'A before a sufficient number of resistance units in the circuit of the counter-balanced electromagnet d have been shortcircuited to cause this counter-balanced electromagnet d to overcome the power of the electromagnet c in whose circuit is included the resistance unit 538and to close the contacts 49, thereby dis-:

establishing the energizing circuits of the.

resistance of theresistance unit 538 is such as to control the translator apparatus to produce just two such openings. I

In like-manner we may assume that'the fourth resistance unit 542 of the group in-z cluded by'the key K will aftera sufficient closure of the contacts 31 controlthe-operation of the relay f, say for .four full operations of this relay after which the balance relay J will again be operated to close the.

contacts 49 having previously been described closing the contacts 59, and the circuit operation from this time on including the dis-. establishingof the battery supply circuit of the rheostat L, and the subsequent operationof the relay 0 in a manner similar to the operation of the relays n and m will now be understood. .The operator therefore having transmitted four trains of impulses corresponding to the tens of thousands, the thou-1 sands, the hundreds and the units of the called-for number will restore the 'key K I have previously described how the operator of the station A desiring to make telephonic connection with the station A, and having removed the receiver-2, from the switchhook causing the switchhook to close contacts 34 in the circuits of the line con.-

' ductors 141 and 142,thereby caused the circuit of the station A to be extended to the first selector E ofF-ig; 2,. and it has heretofore been stated that hereafter the apparatus of. the first selector E was thereupon established tobe operated by the opening and closing of the contacts 31 of the relay f under the control of the translator. Subsequently the operation of the system to cause the opening and closing of the contacts 31 "of the relay f torproduce successive trains,

of current impulses was described.

A general description; of the operation of the apparatus of Figs. 2 and 3 will now be explained to show how the connection is extended from the calling to the called station.

When the contacts 31 of the relay '7 were first operated for the first .digitof the called number which is assumed in this description .to be5124, the contacts 31 of the'relay f are.

extendin springs 1 1 and 172 and private magnet 125 separated twice momentarily, thereby caus ing the selector line relay 147 to-be twice momentarily deenergized. 'Each time. the. relay 147 deenergizes, it closes a circuit through the vertical magnet 151. Since the digit called is 5, the vertical magnet 151 operates five times to raisethe switch shaft and its wipersfive steps, after which the side switch passes to second position, and

causes the rotary magnet 152 to operate in the usual manner'to rotate the shaft wipers onto the contacts of a-n idle trunk line leading-to a second selector F. The said switch thereupon passes to third position and, through the medium of its wipers 153 and line circuit and extends the line conductors through the shaft wipers 155 and 156 and the contacts upon which theyhavebeen rotated to the second selector The line re- ;lay 157 of the second selector thereupon be-i-g the trunk conductors. 158 and 159 to an idle connector H which has access to the group of lines to which that of the station A belongs. lVhen the [connection is, thus extended to the connector H, its line relay 116, which is normally bridged across the conduc- 154:, disconnects the line relay 147 from the y tors 158 and 159 in series with the battery, I

becomes energized. The relay .116 upon energizing, closes the circuit of the relay 126. Whenthe calling station causes the contacts 31 to be operated for the third digit, 2, of

the called number, the circuit of the line relay 116 of the connector is broken twice momentarily. The relay 126 being a. slowacting relay does not havetimeto deenergize during the momentary interruptions of its circuitby the line relay, and there- .fore, each time the relay 116 de'e'nergizes, a

circuit is closed from ground Gr throughv the spring 166 and its back. contact, spring 167 and its front contact, relay 127, verti-- cal magnet. 114 and side switch wiper 124 to the battery lead 170,, and thence'through i battery B to ground G''. Since the digit called is 2, the vertical magnet receives 2 impulses over this circuit and operates to raise the switch shaftand wipers .111, 112 and-.113 two-steps. The relay 127, which is energized in series with the vertical magnet, 1s EL'SlOW-fiCtIHg relay and, upon being energizedby the first impulse, remains in its energized positionuntil after the last impulse is delivered'to the vertical magnet. The relay 127, upon energizinz, completes a circuit from ground G through the and relay 128 in multiple to the battery lead 170. The relay 127 deenergizes and breaks the circuit of the private magnet and the relay 128 shortlyafter the last impulse is TII bv -Wlien the contacts '31 of the relay f of the calling station are caused to be operated for the last digit 4, the circuit of theline relay 116" is broken: four times. Since the side switch is nowin second position, each time same manner as for the previous digit to maintain the circuit'of the private magnet 125 and the relay 128 closed during thef entire time the rotary magnet is operating.-

The circuit of the private magnet 125 and therelay 128 'is'broken shortly after the last impulse is delivered to the rotary magnet, and the private magnet 125 u'pon deenergizing permits the side switch to pass to third position. The side switch Wiper 123, upon reaching third position completes; a circuit from ground to Gr through said side switch wiper, shaft wiper 111, connector-,= private bank contacts and the cutoff windingf 174 of the switch '0 to the battery lead 170." The winding 174, upon energizing, attractsthe armature 175 which-operates to disconmet the battery from the line at the switch C.

The passage of the side switch wipers 121 and 122 to'third position, and the closing iof the contacts 176 and 117 by the deenergization of the relay 128 finally completes a connection between the calling and the called lines. a The passage of the sidefswitch Wiper 124 to third position completes the circuit of theringing relay 129. This circuit extends from ground G through the interrupter 178, relay 129, springs 179, and

cuit branches, one branch passingthrough e the side switch Wiper 124 to the battery lead 170. The relay 129, upon energizing disconnects the calling line from the called line, and connects the ringing current generator M With the called line through the ringing relay springs 181 and 185 and their front contacts, contacts 177 and 176 ofthe relay" 128 and the wipers 113 and 112. The relay- 128 which'controls the contacts 177 and 176, is a slow-acting relay and therefore does not permit its contacts to close, 'until shortly' after'the side'switch has passed the third position and closed the circuits of the cutoff winding 174 of theline switch C. will-thus be seen by the aid of the relay 128 it is impossible for ringing current to be ap plied to the called line until "after the cut-' off winding 17 4 has had'sufiicient time to enthe springs 1'80, conductor 191, private wiper 192 of the selector '5F,si de switch V ergize and disconnect'the line relay225from talking circuit of the called station is bridged across the line and as soon thereafter as the ringing relay'129 deenergizes,

over acircuit extended from ground G at the connector release relay 126, through the sprin s 180, theright-hand windingvof the backridge relay 118, side switch wiper 122, ringing relay springs '181 jand 182,

; springs177, thence to and through the sta tion A andback overthe line 184, wiper 112, springs 176, sprin s 185 and 186, side switch wiper 121 andtheleft-hand winding of the back-bridge relay 118 to the battery said station is provided with talkingcurrent lead 170. Therelay 118 upon energizing, i

closes the circuit of the relay 187. This circuit extends from ground-G through the side switch wiper 123, springs 188 and relay 187 to the battery lead 170. The relay 187 upon energizing-operates to open the circuit of the ringing relay 129 at the springs 179 and, by closing contact between the springs 189 formsa locking'circuit for itself independent of the relay 118, so as not to deenergize again when the called subscriber'hangs up his receiver;- In"the-draw-,

ings the complete talking circuit between"- the calling and the called lines is outlined-- by heavy conductors- 1 After the conversation is completed, the entire connection is released by the hanging up of the receiver at the calling station] During the time the connection is-being maintained, the release relays 190 and 148 of the selectors F and E, respectively, are maintained energized over a circuit extend-' ing from 'groundGr at the connectorthrough wiper 193 and spring "194,Whence the cirthe relay 190 to battery,"while the other fbranch passes through the side switch Wiper ing, breaks the circuit of the relay 1126. [The relay 126,'upon deenergizin'g, closes the circuit of the release magnet 117, saidcircuit extending from ground Gr through the spring 166 and'its back contact, spring 1677 and its back contact, spring 120 and release 1 magnet 1 17tofthe battery lead 170. The

' magnet 1 17, upon energizing,--immediately restores the shaft and side switch Iof'the connector to normal position,andtheswitch breaking of the circuits of the relays 190 and 148 permits the said relays'to dee'nergize so as to close the circuits of their respective release magnets 195 and 196, which, upon energizing, cause the switches F and E to be 20 restored tonormal position. The relay 148,

upon denergizing, also breaks the holding circuit of the holding winding 149 of the switch C, causing said switch to be restored to normal position.

In the foregolng it has been assumed that the line of the station A was idle'when called from the station A. In case said line had been busy, the connector II Would'not have completed connection therewith, and the calling subscriber would have been given a busy signal in the manner set forth in the patent to F. Newforth, Jr., No. 1,078,690, and which need not be described herein, it

being well understood in the art "how the busy signal in an automatic system is produced.

In the foregoing description it was assumed that the operator at station A desir ing to call a line upon which is located the station A operated the'key K Now if some other'station than the station A ofv the system was desired to be called, the operator would depress one of the other ke s,

such as the key K orrthe key K there y' associating With the circuits of the translator resistance coils having different ohmic resistance characteristics in one or more of the resistance units of the group included, and therefore, successive trains of impulses differing from the trains of impulses cre-; ated by the depressal of the key-K,' will be produced, and a different line will thereby be selected; and therefore the operator by selecting the particular key to call a given station can predetermine the characa teristics of the successive trains of impulses produced by the translator, and whichcontrols the operation of the automatic apparatus illustrated in Figs. Qand 3 to select the desired line. V

. While I have illustrated my invention in connection with a particular type of automatic telephone system, it will, of course, be understood that the features of my in- .vention are capable of broader use'and that my invention contemplates the use of the various novel features of my invention'in connection with anautomatic system of any known type, or in connection with a semiautomatic system.

What I claim as my invention is 2- '1. In an electrical translator, the combi I nation with a resistance unit, a controlling relay, means to include in a circuit witha source of current the said resistance unit and the sa d controlling relay, an interm1t-' tent circuit breaker,an electrically operated step-by-s'tep rheostat, means under the control of said controlling relay to include the said circuit breaker and said rheostat in circuit with a source of current whereby said electrically operated rheostat is operated under the control of said circuit breaker, the said resistance unit limiting the extent of operation of said rheostat by said' circuit breaker, contacts adapted to be intermittently made and broken during the opera tion of said rheostat, a selective "switch, and means to include said selective switch and said contacts in circuit with the source of current whereby said contacts control the operation of said switch.

2.'In an electrical translator, the combination with a resistance unit, a controlling relay in the circuit of said resistance unit, the said circuit including the source of current, an electrically operated step-by-step rheosta-t, said controlling relay being under the joint control of said resistance unit and said step-by-step rheostat, said controlling relay controlling the operationof said rheostat, a pair of contacts adapted to be inter-' 'mittently operated duringthe operation of said rheostat under the control of said controlling relay, the said resistance unit limiting-the extent of operation of saidrheostat by its control of the said'controllingrelay to an extent depending upon the ohmic resistance of the said resistance unit, a selec-' tive switch, and means to variably operate said selective switch under the control of the said contacts.

3. In an electrical translator, nation with a selective switch, a pair of contacts included in'the circuit of said selective switch together with a source of current to H operate the said selective switch, a step by step rheostat, means to operate the stepbystep rheostat, means to cause said contacts to be operated during the operation of said rheostat, a controlling relay, a resistance unit, and means whereby the said controlling relay limits the operation of said rheostat, the said means including the said re 1 sistance unit.

4. In an electrical translator, the combination with a resistance unit, an electrically operated rheostat, means to operate the same, a pair of contacts adapted to make and break a circuit including a selective switch and a source of current, the degree of the combioperation of the SZLlCliIlIQOSCtIt depending upon the ohmic resistance of the said resistance unit and thc'number of operations of sa1d contacts and the degree of'operation of sa1d selective switch depending upon the extent of operation of said rheostat. V

5. Invan electrical-translator, the conibi I nation with a pair of contacts adapted to make and break a circuit, a selective switch and a source of current included in the sa1d circuit, sa1d pair of contacts variably controlling the said switch, a resistance unit, a

step-by-step operated rheostat, means to cause the said rheostat to operate under the;

control of said resistance unit, the degree of opera-tion of said rheostat depending upon the ohmic resistance of said resistance unit,

' and the-number of operationsot' said con- 7. In an electrical system, the :combina-- tionwith a reslstance unit having a definite ohmic res1stance,;a pair of contacts adapted to intermittently make and break a circuit including an electrical lresponsive device, and a translator to translate a measure of the, ohmic; resistance of the said resistance unit into'a definite number of operationsof,

said pair of contacts to variably operate the electrical responsive device.

.8. In anelectrical system, the combina tion with a resistance unit having a definite ohmic resistance, a pairof contacts adapted to intermittently make and break acircuit including an electrical responsive device, a

translator to translate a measure of the ohmic reslstance of the saidres1stance unit into a definite number of operations of said pair of contacts to variably operate the electrical responsive device, a second resistance unit, an automatic switch toeifectivelyinclude the second resistance unit in the circuit of the said translator to control the same and to exclude the first resistance unit from the said circuit, and means to cause the continued operation of sa1d pair ot contacts to cause a second train of operations thereof under the control of the second re sistance unit,

9. In an electricaltranslator, the .combi n-ationwith an electrically operated step-bystep rheostat, means to operate the same, a

pair of contacts controlled by the said means during the operation of the said rheostat,

and controlling means including a resistance,

unit and a balancing device to; cause the saidrheostat to operate causing a definite number of operations of the said contacts, l

said contacts under the manuals the number dependingup'on the ohmic re sistance l 4 i 10 Inan electrical'system, the combina: tion'w'ith an automatic telephone system ineluding selective switches to select adesired line, a pairof contacts adaptedto control the operat ioni of the said switches, a resistance unit, and an electrical translator, said translator controlling the operation of the the said resistance unit.- 7 v v 11. I-n an automatic telephone system, the combination with a selective switch containing a movable} contact and alplurality offixed contacts, aplurality of telephone lines connected to the fixed contacts, means to variably operate the said movablecontactto make co'nnect1on ,with a desired fixed contact, a pair of controlling contacts for thel sa1d selective switchcontrollingthe movement of'ith'e said movable contact, an electrictranslator, a plurality ofresistance units,

primary control of.

switch contacts to include a desired one of the said resistance units in circuit with the said translator wherebythe said translator controls the operation of the said contacts variably according to the particular resist:

ance unit used, to variably control the oper- I ation'of said selective ,swi tch..

1-2. In an electrical system, the combinaf tion Wlth-a plurality of groups of resistance units, each group consisting of alfplurality of resistance units, each resistance ;unit "havmg a defin te predetermined ohmic resist-' ance, an electric translator, a pair of contacts adapted to beoperated thereby, a selective switch under the control of thesaid' conta cts to make connection betweena first circuit and a desired onezof a plurality 015 other circuits,switchingflmeans to associate all of the resistance units of a group in circuit withthe said translator, means to include in sequence the different resistanceunits of the.

associated groupin circuit withsaid translator, whereby thetranslator is variablyop' erated under the control-of eachof the re sistancennits in turn, thezdegree of operation in each case depending upon, the ohmic resistance ofthe particular-unit, the-opera tion of the 3 said switching means thereby,

causing successive trains of operations of the said contacts. t

13. In a telephpne systennthe combination with a plurality: of telephone lines extending by their limbs from stationsto an exchange,

1 a plurality offixed switch contacts for the said lines at the said exchange, a movablc contact adapted to be brought into connec-' tion with any of the said fixed contacts whereby connection is adapted to be made between the said movableicontact and any of thesaid lines-a source of current, an elec-' tromagnet and a pair of contacts cont-rolllng the same tocause variable operation ofthe said switch, an electrical translator adapted a desired line.

to variablycontrol the said contacts aplu rality of resistance units: for the said trans lator, and means to include av desired one of the said resistance units 1n circuit with 14. In an electrical system, the combination with a pair of contacts adapted tomake and break a circuit, a selective switch, a source of current in the said circuit, an'electrical. translator, and electrically operated rheostat therefor, means to operate the same,

a plurality of resistance units adapted .to be associated with the said ftranslator, means to cause one-0f the said resistance'units to control the extent of operation of the-said rheostat to be included in the circuit ofthe said translator tov control the extentof oplator, the said pair of contacts being, adapted to be operated a proportionalnumber of times to the extent of operation :of the said rheostat, circuit connections and apparatus limiting the extent ofthe operation ofsaid rheostat to a degree depending. upon the ohmic resistance of the said resistance unit, the said selective switch being variably operated depending upon the ohmic resistance of the particular resistance unit included in circuit with the said translator;

15. In an automatic telephone system, the combination with a telephone line leading from a calling station to an exchange, selector and connector switches at the exchange adapted to make connection with other lines leading thereto, a plurality of resistance units, each having definite ohmic resistances,

a translator to translate in sequence the ohmic resistance of the different resistance units, each into a definite number of oper-.

ations of thesaid pair of contacts, a source of current associated with the said automatic system adapted to produce under the control of said contacts during the said 'successive operations of the same successive trains of current impulses, and electromagnetic means associated with the said selector and connector switches to variably operate the said switches, the'degree of operation of said switches depending upon particular values of ohmic resistances of the said resistance units.

16. In an electrical system, the combina tion with a resistance unit having a definite ohmic resistance, a pair of contacts adapted to intermittently make and break a circuit including an electrical responsive device, a

translator to tr'anslate'a measure of the ohmic resistance of the said resistance unit into a definite number of operations of said pair of contacts to variably operate the electrical responsive device, a second electrical responsive device, a second resistance unit,

and means to subsequently supersede the first resistance unit with thei'second resistance Iunit, and to subsequently'translate the measure of the ohmic resistance of the second resistancennit into a succeeding definite numberv of operations of said-pairof contacts to operate the said second electrical responsive device. V

17.. In an electrical system, the combination witha plurality of resistance units having definiteohmic resistances, a pair of contacts to, intermittent ly' make. and break. a'

resistance units in the group, means toclose the switch contacts of a resistance unit in each group, a pair ofcontactsadapted to intermittently make and break a circuit including a step by step responsive device, a translator, automatic means responsive to the closure of said switch contacts to suecessively operatively associate the said translator and the difier'ent resistance units whose switch contacts have been previously closed, and means to cause the said translator tov operate the said pair of contacts under the having a diflerentresistance fromctherj successive control of the different associated resistance units.

19. In an electrical system, the combina tion with a resistance unit having a definite ohmic resistance, a pair of contactsin a circuit including a source of current and a current impulse operated device, a transla tor interlinking with said resistance unit and the said pair of contacts, the said translator operating under the control of said resistance unit to cause the said contacts to operate a definite number of times depending upon the ohmic resistance of the said resistance unit, and to cause the said current impulse operated device to operate a predetermined number of steps.

20. In a telephonesystem, the combination with a plurality of groups of resistance units, each having a definite ohmic resistance, a switch contact in the circuit of each resistance unit, each resistance unit of the group having a different resistance from other resistance units in the group, means to close the switch contacts of a resistance unit in each group, a pair of contacts adapted to intermittently make and break a circuit including a step by step responsive device, a translator, automatic means responsiveto the closure of said switch contacts to successively'operatively associate the said translator and the different resistance units whose switch contacts have been previously closed, meansito cause the said translator to "operate thesaid pair of contacts under the successive control of the different associated resistance'u'nits; a movable contact associ- 10 ated with the said step by step device, a plurality of stationary contacts'f therefor, and means, responsive to the intermittent closures of the said contactsunder-the control of the said resistance units tof 'opera- 1'5 tively connect the saidmovable' contact in an electrical circuit with a desired one of the said stationary contacts.

21.1111 an-electrical system,a progressively operable switch arranged to occupy a plu- '2'0 rality of selective positions, twocircuits cooperating-in the control of said switch, means for directively including resistance units in one circuit,,means to include resistance units in the other circuit as said switch is bein advanced, and means for stopping said swltch When'the resistance values of one circuit bears a certain relation to the resistance values of the other circuit;

said switches.

plurality of selective positions, and circuits "and resistance units arranged as :a' Wheatstone bridge to .directively controlfthe set ting of said switch.

23. In anelectrical system, a plurality of circuits, means including link'circ'uits and directively operable switches for inter-connecting apair of circuits and othe'r'circuits' and V resistance units arranged as a Wheatstone bridge to directively control the setting of .24; In an electrical-systempa pluralityof V circuits, mean's including link circuits' and v directively operable swltc'hes fOI IHfiGT-COII- V necting a pair of circuits, controlcircuits, resistance-units, means for directively in-' cluding saidYresist-ance units in certain of said circuits,v means to include resistance units in'ano ther of said control circuits as said switchesare bemg advanced and means forfstopping said switches when theresistance values of one circuit bear a certain relation to the resistance values of the other I circuits. a v

In Witnessvvhereof, I hereunto subscribe my name" this 22nd day of JunefA. D; 1917.

FRANK M, sLoUGH

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