US1443494A - Telephone automatic trunking apparatus - Google Patents

Description

' Jan. 30, 923. 1.443,494

T. G. MARTIN. TELEPHONE AUTOMATIC TRUNKING APPARTUS.

ORIGINAL FILED JAN. I7, 1907. 4 sI-II-:FIs-sHI-:ET l

II I. I

Jan. 30, 1923.

T. G.MART 1N. TELEPHONE AUTOMATIC TRUNK Ne APPARATUS.

4 sHEET$-sHEET 2 ORlG NAI. F| LED JAN. 17. 1907,

4 www 'T. G. MARTIN. TELEPHONE AUTOMATIC TRUNK Nc; APPARATUS.

4 SHEETS-SHEET 3 0R G l NAL Fl LED JAN. I7 1907.

T. G. MARTIN TELEPHONE AUTOMATIC TRUNKING APPARATUS.

ORIGINAL FILED JAN. I7, 1907. 4 SHEETS-SHEET 4 503171472 @A5/54951 65.2% f ff I W Patented Jan. 39.19.23;

UNITEII TA'I'ES Parent TALBOT o. MARTIN, or CHICAGO, ILLINOIS, assIsNon, 'er IansNnAssIGNivinNrs, To `AU'roivIATIcnnncfrnrcCOMPANY, A conroeafrIoN or ILLINOIS.

TELEPHONE AUTOMATIC TRUNKING APPARATUS.

yApplication led January 17, 1907, SerialfNo. 352,894. Renewed .Tanuary'28, 1918. Serial No; 214,252.

` To @Hamam/ may concern.' K

Be it known'that I, TaLnorG. I/LIRTIN, a citizen ot the United States of America, and resident of Chicago,`Cool C n1i1ity,Illi `5 nois, have invented a certain new and useiu'l Improvement yin Telephone uton'iatic 'Ilrunking Apparxrtumot which the tollowing' is aspecitication.

My invention relates to Atelephone er-I change systems in general, but more particularly to automatic `or semi-automatic sysw tems, and especiallyto` common battery tele- `phone .exchange systems in which provision is made for enabling` the'calling subscribers to automatically trunk betweentwo distant exchanges, or between different divisions oi the same exchange.

.Inmy Patent No. 1,185,522, granted May 30, 1916, I have disclosed a combined selec- L torand repeater,vandias tar as'this yfeature ot my `present invention is concernethit is in the nature of an improvement on said `previous application. As 'hereinafter described, 'I now provide ya combined selector and repeater-which vis adaptedfor use in trunking in one and the same directionthat is to say, which has the 'functions ot' both a selector and arepeater torftrunlring to another exchange,or to theother division ofthe same exchange. A herein disclosedv embodimentof my present invention com-k prises, for example, a first-selector which is individual to the calling subscribers line, which is provided with means tor automatically selecting an `idle trunk line, and which is further provided with means 'by which its line relays have the additional function of: then acting as repeater relays tor `controllingone or more automatic switches at the other exchange. or at the other division ot the same exchange. ln another embodiment ot' my invention, as herein described and illustrated, I provide `seconthselectorswith which Vthe calling sub-- seribers make connection through the medium of first-selectorsor 'other suitable automatic switches, and which second-selectors are adaptedto serve as both selectors and repeaters for automatically trun'lring vto and `then vcontrolling the operations ot the switches at the Aother exchange. or at. the other `division of the same exchange. In these/as wellvas in other obvious embodiment-s of my invention, it will "be seen that I provide `a system and apparatus ot 'such character rthat the calling subsc 'iber may 7 tiene@ transmit electrical impulses foroperatinp;

an automatic selector switch containing means by whichk all subsequent impulses transmitted 'from the callingv substation are not employed I'or directly controlling -the switch ror switches at the other exchange, or at the other division ol` the same exchange, but to the contrary `are employed for merely actuating a pair ot linerelays which repeat the impulses and thus directly control the operations of vthe next or succeeding-switch or switches. In other words, I provide an automatic` trunk-selectingswitch having a pair of line relays adapted to first control the operations ot' the said switch, and, atter'theproper selection thereby of an idle trunk line, then repeat to the y next or succeeding ,switch or switches yall subsequent electrical impulses transmitted byv 'the calling` subscriber. y'In thisway the said line relays have Athe double function controllingtheir allotted switch mechanism and servingas repeater relays for controlling` other automatic switches. rFurthermore, andas a `feature of special improve ment, these` relays not only lhave the double function of .controlling their allotted selectors and repeating impulses to the subse quentswitoh or switches, but also have the additional function otserving as resistance and impedance elements for feeding ,talks ing current from the battery or other cen` tralized source to the calling subscribers line for talking'.purposes-that is to say, `for charging theimicrophone transmitter at the 'fallmg subscribers substation.` Vith these andsuch other 'features and 'Combinations as may appear from Vthe following,- description and accompanyingdrawings,- I Iind.v that a. considerable saving' is accomplished. especially with respect to the kcost 0I' in-vv stallingi and maintaining;` the apparatus` well as with respect to the primarycost ot (.-onstruction or manufacture. I

` In the accompanying drawings, Yl `igares 't and 2 'taken together show diagrammatically an established connection between a calling and a called substation, in a system f embodying the `principles of my "invention, The telling substation is shown at and the called substationat A. vFor-thebroader purposes of my invention,` 'the subscribers may `be considered. allotted to either the.

, same or different exchanges; butin `this'mise iolv ` .by many well-known features. For example: The subscribers lino vor `individual switch C is an improvement on the selector shown in Patent No. 815,321.. grunted March 13, 1906,to Keith, Erickson and lhfickson. The said switch (l, in additionto performing` the ordina-rv functions ot the selector, also performs the functions oil a repeater, as will be explained. Thus l combine in one switch the features ot a selector and a repeater for use in trunking or calling in one and the same direction. f

The selector F is a modified form of selector, being used in the system asa secondselector; and the connector D is an improvement on the connector shown in Patent No. 815,176, granted March'18, 1906, to Keith, Erickson and Erickson, being an adaptation or' such connector for common battery work. The switch E of the called line-is, ot course, the same 'as' the switch C ol the calling line; and the substations are also, oi course, all the same; but where only one battery is used for two or more exchanges aV battery lead must ot necessity be extended from the battery office to the other central oiiices. This, however, isusually undesirable in most cases, and one battery is therefore provided for etiche-Xchange, as shown in the drawings, where battery B is allotted to eXchanget1 and grounded at G, and where battery B is allotted to exchange and grounded at G.

Fig. 3 of the d rawings shows the switch C used in a different position in the system-- that is, after the selector .l-and is therefore used as a second-selector. The said selector J is also of the type-disclosed iu the.y

said selector patent.

Fig. 4 shows the switch C diagran'unatically and in perspective.

The substations A and A may be of any suitable or approved type. A- comprisesl a receiver 2, switch-hook 3, in-

duction-coil 4 which consists of the primary winding 5 and secondary winding 6,v transmit-ter 7, condenser 8, ringer 9, impulse wheel 410 which has the usual vertical impulse teeth 11 that are adapted to operate the vertical impulse spring 12. The impulse wheel carries 'the rotary impulse tooth 13 The substation which operates the rotary impulse spring 14. The switch-hook has radiating from its body a number of cam arms 15, 16 and 17, and is pivotally secured to the keyboard (not shown) by the screw 1S about which it moves when the receiver is removed.V The movement is produced by a spring (not shown), and the switch-hook is pushed up for the purpose ot changing certain circuit connectionsto be disclosed. The cam arm 15 controls the so-called locking arm 19. After the dial is rotated the locking arm 19 occupiesthe position shown at substation A. rlhe mechanical operations by which this brought about are well known. vrllhe' cooperating groiind springs 2t) and 21 engage, thus placing the groundpost in contactwith the substation ground ti. whereby when the subscriber releases the dial, as dcs'cribed, the vertical impulseteeth 11 will then cause the vertical. impulse spring 12 to' come into Contact with the ground post 22; and immediately following, the rotary 'impulse toothvr 13 causes the rotary impulse spring' 14 toco-me into contact with the same ground post 22. When the switch-hook is down the cam arm 17 maintainsa contact between the springs and 24, thereby bridging the condenserl 8 in series with the ringer 9 across the line. The springs 25 and 26 are then disengaged, and thel primary circuit, including the winding 5' in series with the transmitter 7, is interrupted by the separation of the springs 25 and 26.' The signaling device whereby a subscriber may' signal another after a connection has been established comprises a push-button 28 and a spring 29, which latter normally engages the contact point 30; but whenthe push-button-28 is pressed, the spring 29 leaves the contact point 30`and engages the Contact point 31 which is connected with the substation ground G. Means whereby the subscriber may release the central station apparatus brought into service comprises three springs 32, 33' and 34 known as the release springs, and so controlled bythe cani arm. 1G that when the switch-hook descends thc three release springs are brought'into con.- tact, thereby grounding both the subscribers line conductors simultaneously.

.lhetirst-selector switch C, shown in Figs. l, 3 and 4, embodies, among other details. the vfollowing 'well known devices and circuits: A switch-shaftJ 38 which carries the vertical and rotary line wipers 39 and 40, respectively, and. the private wiper 41. The said wipers are adapted toengage the banks K and L. The side switch M is well known and comprises the side switch wipers 42, 43, 44, 45 and 35 whichmay be designated vertical, rotary and private f side switch wipers, and the rotary magnet side switch wiper and pole-changer wiper, respectively. rlhe side switch is under the controlo? the llt Mii

. ent is omitted in the selector' F. cal line relay 64 controls the vertical magprivate magnet 46. Through the medium of the vertical line relay 47, and while the side switch is in iirst position, the'subscrbercontrols the vertical magnet 48 which latter operates toraise the shaft and shait wipers 39,4() and 4lrvertically. By means of the rotary line relay 49, and while the side switch is in vtirst vor seco-nd position, the subscriber controls the private magnet 46 and, therefore,.the side switch. While the side switch is in second position the rotary magnet 50, which carries the shaft and shaft wipers `in a rotary or circular direction, is energized. The vertical and rotary line relays 47 and 49, acting conjointly, vprovide means whereby the subscriber controls the release magnet 5l while the side switch is in First, second or third, position.` The polechanging relay 3G is provided for shifting the lead of the'rotary line relay 49 from main battery to the ground terminal of the battery when talking battery current is provided bythe connector. Ilurthermore, the shaft 38 is provided with the vertical and longitudinal teeth 52 and 53, respectively, which are adapted to be engaged by the rotary and vertical armature pawls 54 and 55 when their respective magnets become operatively energized-- The normal arm 56 controls the springs 57 and 58, The function of the coil spring 59 is to return the sha'tt 38 to normal position after the said sha'tt has been released by the operation ot the release magnet 51. The lamp 60 is provided tor indicating tothe switch attendant whether or not the switch isin an operated position. It will be noticed that through `the condenser 6l the subscribers incoming verticalline conductor is transposed to the outgoing rotary line; similarly, through the condenser 62 the subscribers incoming rotary line conductor is transposed to the outgoing vertical line` The differed tial relay 63 controlsthe release magnet circuit, and when the side switch M is in third position the said relay controls the energizing circuit ot the pole-changerrelay 36.

The Lsecond-selector F has the vertical and rotary line relays G4 and 65, but insteadot being connected to the battery lead through the ln'idge-cut-ot springs, said relays are connected direct to the battery lead. The ln'idge-cut-oit relay of the said selector patrihe vertinet (36, and the rotary line relay 65`controvls the private magnet G7, which latter in turn controls the side switch. The two line relays 64 and 65, acting conjointly, provide means whereby the release magnet 68 may become energized. The release relay 69 controls the releasing ot the switch after the side switch has passed to third position and established connection with a connector switch. li'luthcrmore, therotary magnet 7 O,

when the side switch is in second position,

operates to give the shaft wipers 7l, 72 and 7 3 a rotary or circular motion. i

The connector l) is ot the type disclosed in my latent No. 1,382,226, granted `March `2, 1920. The vertical and rotary `line relays 74 and 75 operate to impart to the shaft wipers 7G, 77and 78 their vertical and rotary motion, respectively-` While the side switch is in rst position, the vertical line relay 7 4 controls the vertical magnet 7 9, and when 'the side switch passes to second position the rotary magnet comesunder the control` ci the said relay; and similarly, when the side switch is in third position the ringer relay 8l is placed underfthe ycontrol ot the vertical line relay 7 4. The connector rotary linerelay 75, as is well known, controls the private magnet 82, which'latter in turn operatesto shift the side switch wipers 83, S4, and 86 'trom iirst to second po-VK sition and from second to third position. The two line relays 74 and 75, acting conjointly, provide means whereby the release magnet 87 may be energized to relea'sethe said switch. rThe `diiierential relay 88 controls the energizing circuit of the lbackbridge relay S9, throughwhich Vlat-ter the called substation recevies battery current for talking purposes. Said relay 89, uponenergizing, closes a circuit which in turn pro vides the calling substation with battery los the switch-hook 3 and operating the dial for.

, the iirst digit 2, the vertical and rotary line conductors 90 and 91 are alternately ground ed, the formed ytwice and the latter once,V

upon the return motion ofthe dial. Grounding the vertical line conductor 9() closes an energizing circuit through the vertical line relay 47 ot the lselector (l, said circuit `temling from.ground Gf through the ground springs 2() and 2l, ground post 22' impulse spring l2, conductor Sii/),conducto'r 92, vertical line relay 47, windingfl otthediti'erential relay to the battery lead 94, thence through battery B and to ground Gr.` Each time that the 'vertical line relay47 operates,

iis

an energizing circuit is established.through the vertical magnet extending froml ground G2 through the springs 95 and 9G, conductor l7, -side switch wiper 42,A contact point 9S, through the vertical magnet 48,

fil (l conductor 99, private magnet. springs v100 and 101, conductor 102, springs 103 and 104 to the battery lead 94. thence throughbattery B and to ground G. The vertical magnet 46 `in turn operates to raise the shaft and s-hattwipers 39, and 41 two steps. Following 4the vertical impulse the rotary line relay 49 becoi'nes energized over a cir,- cuit extending from ground G, impulse spring 14, rotary line conductor 91, conductor 105, rotary line relay 49, winding 106` Vofthe diiizerential relay 623, through the springs 103 and 104 to the battery lead 94,l tllence through battery B and to ground G. The rotary line relay 49, upon operating, presses the springs 95 and 10T into contact, wliereby au energizing circuit is closed through the private magnet '46 eX- tcnding from groundjGz, springs 95 and 107, conductor 106, side switch wiper 43, contact point 109, conductor 110. pr- 7ate magnet 46 lto the battery lead 94, thence through battery B and to grounc G. The private inagnet, upon o 3er-ating, releases the side switch M to second position, w viereby an energizing circuit isset up through the rotary magnet 50. Said circuit extends trom ground G3 lthrough the side switch wiper 45, contact point- 1'11, conductor 112, interrupter springs 113', rotary magnet 50 to the battery lead 94, thence through battery B and to ground G. The rotary magnet is energized one step, and the shaft wipers 39, 40 and 41 are carried into engagement with bank contacts that constitute the terminals of a trunk line the conductors ot which are similar to the trunk conductors 113 and 114 leading from the tenth set ot contacts of the second level, and which conductors 113 and 114 terminate in the switch F at the exchange #2. But it the i'irst trunk line is busy the iirst private bank contact is, of course, grounded, and an energizing circuit is established through the private magnet 46 when the L rivate wiper 41 strikes the grounded private ybank contact, thereby retaining the side switch in second position and maintaining the energizing circuit through the rotary magnet 50. The rotary magnet, by continuing to rotate the wipers, breaks the energizing circuit ot the private magnet 46 as soon as an idle trunk line is found, and as soon as the private magnet de-energied the side switch is 'tripped into third position; but if there are no busy contacts to be passed over, the rotary magnet 50, as is'well known, trips the side switch to third position. It', iowever, the iirst nine trunks are busy the shaft will' b erotated onto the tenth set ot side switch wipers 42, 43, 44, and engage their respective contact points 115, 116,

11'?, 113 and 119, thus extending the subscribens line conductors and 91 to the se-l lector F. Also, since the side vswitch wiper 44 engages the grounded contact point 11T, a guarding potential is established at the private wiper 41 tor protecting the seized trunk line trom being molested by any other switch. Furthermore, on the iirst vertical step' of the shaft the normal arm 56 permits the normal springs 57 and 58 to engage. thereby closing a circuit through the signal lamp 60 as follows: from ground G1 through the springs 57 and 5S, lamp 60 to the battery lead 94, thence through battery B and to ground G. The lamp, upon glowing, indicates to the switch attendant. that the allotted switch is in anv operated position. The subscriber, upon grounding the line conductors 90 and 91 tor the second digit 2, energir/.es the vertical and rotary line relays 4T and 49 as before, since the line rel ys are permanently bridged acrossthe line; but. the said relays upon energizing in turn operate to ground the trunk conductors 113 and 114, as will be explained. Now, since the side switch v4 has passed to thirdl iosition, the impulses are repeated to the vertical and rotary line relays 64 and 65, respectively, ot' the selector switch F which is located in the central office .71722. The vertical line relay 4T energizes and operates as stated; but when the springs and 96 engage, an energizing circuit is closed through the vertical line relay 64 at the selector F over the itollowing circuit: From ground G2, springs 95 and 96, conductor 97. wiper 42, contact point` 115, conductor 120, springs 121 and 122, conductor 123, shaft wiper 39, trunk conductor 113, side switch wiper 124, contact point 125, vertical line relay 64 to the battery lead 126, thence through battery B and to ground G. The vertical line relay 64 upon energizing places the springs 127 and 128 in contact, thereby closing an energizing circuit through the vertical magnet 66 extending trom ground G5 through the springs 12T and 123, private springs 129 and 130, vertical magnet 66, 'thence to battery lead 126, and 'from battery to ground G. rhe vertical magnet v,operates to carry the shalt wipers T1, 'i' 2 and 73 two steps opposite the bank level in which are located the terminals ot the trunk lines leading to' the connectorD, Fig. The rotary line relay 49 of the selector C upon energizing places thesprings 107 and 95 in contact, .,Vhereby an energizing `circuit is closed throughthe rotary line reiay 65 ot the selector switch F. This circuit extends from ground G2 through the springs 95 and y107, conductor 108, side switch wiper 43,

contact point 116, conduct-or 131, springs 132 and 133, conductor `134, shaft wiper 40, rotary trunk conductor 114, side switch wiper 135, contact point 136, rotary line relay 65 to 'the battery lead 126, thence through battery Bto ground G. The rotary line relay 65, upon energizing, closes an energizing whereby an energizing circuit is closed through the rotar" magnet extendinol o M t x 2,-; trom ground (J, Contact point 108, side switch wi'ier 139 interruater sorinos 14() through the rotary magnet mito the battery leady '126, thence through battery B to ground G. The rotary magnet, upon'operating, rotates the shaft wipers, as is well known, onto an idle trunk line. 'Vhen the idle trunk line is seized the side switchV wipers pass to third position, thus extending the calling' subscribers line conductors 90 and.` 91 to the conductors 141 and 142 which, it will be assumed, lead to the connector D. Furthern'loro, when the side switch wiper 143 passes to third position, a guarding potontial is established at the private wiper 7K1 (which latter has engaged the conductor I4/1 rlor. protecting the seizedy line against being molested byother switches. The et'- t'ect out grounding the line conductors 90 and 91 for the last two digits (naught and naught) is directed toward the connector D bjr' the selector switch C in the manner in which the second digit operation was directed toward the selector switch F. Grounding the verticalline conductor 99 'ten times for the third digit operates the vertical line relay 47 ot the selector switch C ten times, aspreviously explained; the said relay inturn repeats the ten impulses, grounding the vertical trunk` line conductor 113 ten times, which conductor is now extended to the connectorvertical line relay 74. The connector vertical line relay 74, therefore, becon'iesenergized over a circuit extending from ground G2 at the selector C, as explained, to the conductor 113, thence through the side switch wiper 124, contact point 145, conductor 141, vertical line relay 74,through the winding 146 ot the ditlerential relay 8S to the battery lead 126, thence through battery 13A to ground G. rThe relay 88, of

course, becomes energized, since the winding .146 is in series with thel relay 74; but the energization o't the said'diliercntial relay at this time is without effect.

Each; time that the vertical line relay 74 is energized the line relay springs 147 and 148 are pressed` into contact, thereby closing an energizing circuit` through the vertical magnet 79 over the following path: From ground G tothe springs 147 and 148-, private magnet springs l149 and 150, side switch wiper S6, Contact point 151, vertical magnet 79 to the battery lead 126, thence throngh battery B to ground G. The vertical mag`- niet, thus energized, operates to raise they shaft and shaft wipers one step at a time until the said wipers arecarried ten steps 1 to the bank level in which are-located the terminals ot the line al1-2200. lVhen the rotary line conductor 91 is grounded the r0- tary line relay of the switch@ is energized, which in turn operates to ground the rotary trunk conductor 114, whereby the connector rotary line relay becomes energized through the following path :from ground G2 to the rotary trunk line conductor 114, as eplained, side switch wiper 135, contact point 152, shaft wiper 72, trunk conductor `142, rotary line relay75, winding 153 of the differential relay 8S, springs 154 and 155 to thebattery lead 12G,`thence through battery B to ground G. Since the winding'153` ot the differential relay 88 is in series with the rotary line relayl 75, the difterential relay 88 becomes operative, but' at this time `it is without effect. The energiza.- tion of the rotary line relay 7 5 causes the energizationy of the private niagnet 82 over a circuit extending 'trom ground G through the springs 147 and 156 to the private magnet 82, springs 154 and 155 to the battery lead y126, 'thence through battery B t()` ground G. released from first to second position, thus placing the wipers 83, 84, 85 and 86 ink connection with the contact points of Lthe second position. The last digit beingnaught, the subscriber operates the dial, as previously described7 grounding the vertical `linelconductor ten `times and the rotarylineconductor 91 once. The vertical and rotaryline relays 74 and 75 are opera-ted over `previously traced circuits. However, when the connector line relay springs 147 and 148engage, a circuit is closed throughthe rotary magnet 8O instead of through the verticali As a result the side switch is` magnet 79. `The energizing circuitextends from ground G through the springs 147 and 148, private magnet springs 149 and 15,0, side switch wiperSG, contact point 157, `rotary magnet S9` to the battery.` lead126, thence through battery B to ground G. time that the rotary magnet is energized it operates to rotate theshatt and shaft wipers 7G, 77 and 78 one step at time until the Each said wipers are carried into engagement with the normal conductors 159, 159 and 1GO. the 'toriner two ot which load to the line ,terminals of the desired: subscriber. V

operation is brought about inthe welk" lsnown` manner.v Assume the former result to occur and the side, switch to pass to' third position, tlnis'placm'g-the side switch wipers 83, 84, 85 and 86 in contact with their i ispective fontact points in third position. Furthermore, when the side switch passes to third'position a guarding potential. is established for protecting the called line. This potential extends from ground G7, contact point 161 to the side switch wiper 85, switch shaft wiper 78, which latter engages the private contact of the called line. The said guarding potential also closes an energizing circuit through the pole-changing and cutoff relay '162 of the selector E. To signal the called subscriber the calling subscriber presses the signaling button 28, placing the contact 29 in contact with the substation ground, thereby energizing the selector vertical line relay 47 and in turn the connector vertical line relay 74. The path of the energizing circuit extends from ground Gr through the springs 2O and 21, contact point 31, spring 29, springs 26 and 25 to the vertical line conductor 90, thus energizing the selector vertical line relay 47, as explained. r1`he said relay repeats the impulse from ground G2 to the conductor 113, side switch wiper 124, contact point 145, shaft wiper 71, conductor 141, through the vertical line relay 74, winding 146 of the differential relay 88 to the battery lead 126, thence through battery B and to ground G. It will be remembered that the connector side switch has passed from second to third. position, and that the side switch wiper 86 is in engagement with the contact point 168, thereby placing the vertical line relay 74 in control of the ringer relay 81 in the same manner in which the rotary magnet 8O came under the control of the vertical line relay when the side switch passed from first to second position. Therefore, when the vertical line relay presses the springs 147 and 148 into Contact. the ringer relay 81 is energized by a low of current from ground G through the springs 147 and 148, private magnet springs 149 and l150, side switch wiper 86, contact point 163, ringer relay 81, springs 164 and 165 (bearing in mind that the differential relay 88 is energized) to the battery lead 126. thence through battery B to `ground G. The ringer relay, upon energizing. shifts the spring 166 out of contact with the spring 167 and into engagement with the spring 168.` and the spring 169 is shifted into engagement with the spring 170. This `results in bridging the terminals of the ringer vgenerator lil across the called subscribers line'. A signaling current is therefore sent from the generator H to the ringer relay springs 170 and 169, side switch wiper 88, contact point 171, shaft wiper 7 6,

normal conductor 158, vertical line conducA tor 172, condenser 173, ringer 174, springs 1.7 5 and 176 to the rotary line conductor 17 7, rotary normal conductor 159, shaft wiper 77. cotnact point 178, sied switch wiper 84,

ringer relay springs 166 and 168 back to the generator H. As soon as the calling subscriber ceases to press the signaling button 28 the ringer relay 81 becomes de-energized and the springs 166 and 169 resume their normal positions. The subscriber at substation #2200, in response to the signal, removes the receiver 179 from the switch-hook 180, which allows the springs 181 and 182 to engage, and the springs 175 and 176 to disengage, thereby removing the ringer 174 from across his line. The engagement of the springs 181 and 182 closes a series energizing circuit through both windings of the relay 89 at the connector D, said circuit extending from ground G7 to the contact point 161, side switch wiper 85, winding 1.81 of the relay 89, through the ringer springs 167 and 166, side switch wiper 84, contactk point 178, shaft wiper 77, rotary normal conductor 159, rotary line conductor 177, primary winding 182, transmitter 188, through the signaling device of the called substation, through the springs 181 and 182', vertical line conductor 172,'normal conductor 158. shaft wiper 76, contact point 171, wiper 83, through the winding 184 of the relay89, springs 185 and 165 to the bat tery lead 126. thence through battery B and to ground G. The relay 89, upon energizing, operates to shift the spring 154 from the spring 155 (which latter is connected to the battery lead 126) to the spring 186, which is in turn connected with ground. This reversal of the polarity of the spring 154 sets up a circuit which energizes the pole-changing relay 36 of the selector C. Thiscircuit may be traced from ground G7 to the contact point 161. side switch wiper 85, through the springs 186 and 154, winding 158 of the differential relay 88, rotary line relay 7 5, conductor 142, shaft wiper 72, side switch wiper 135, rotary trunk line conductor 114. shaft wiper 40, conductor 184 (Fig. 4). sin-.ings 186 and 187, contact point 119, side switch wiper 85, conductor 188, through the pole-changing relay 86, conductor 128 to the vertical line shaft wiper 39, vertical trunk conductor 118, side switch wiper 124, Contact point 145, shaft wiper 71, conductor 141, rei-tical line relay 74, winding 146 of the differential relay 88 to the battery lead 126. thence through battery B and to ground G. The relay 86. upon energizing, operates to disengage the springs 121V and 122 and. springs 182 and 188, and to shift the spring 108` out of Contact with the spring 104 which latter is connected with the battery lead 94) into engagement with the spring 189 which is in turn connected to ground. This operation of the relay 36 closes a cirruit which provides the calling subscriber with battery current for talking purposes. The/'said circuit extends from ground G3 through the side switch wiper 45, Contact point 118,` conductor 190, springsV 189- and 103, through the winding 106 of the differential relay 63, rotary line relay49, conductor 105, rotary line conductor 91, primary winding 5, transmitter 7, springs 26 and 25, vertical line conductor 90, conductor 92, vertical line relay 47, winding 93 of the differential relay 63'to theJ battery lead 94, thence through batteryr B and tov ground Gr. The two substations being thus provided with battery current for talking purposes,

communication may now be carried on overl thecircuit shown `by the heavy lines in Figs. 1 and 2. n l

The release ofthe 'switching apparatus is brought about when the calling subscriber restores the receiver 2 tothe switch-hool 3, thereby pressing the release springs 32, 33 and 34 into engagement for a moment. The Contact ofthe said release springs grounds the vertical andl rotary line conductors 90 and 91 simultaneously from ground G" to the releasespr1ng32, thence through the n springs 33 and 34 to the rotary and vertical line conductors. The grounding of' the roi tary line conductor 91produces a short-circuiting or shunting of the rotary line relay 49 in series withthe winding 106of the dif'- ferentiall relay 63, extending from ground G3 to theoside switch wipe-r 45, contact point 118,1springs 189and 103, winding-106 of the differentialrelay 63, rotary line relay 49 tol the rotary line conductor 91, to therelease springs 33and 32 to groundG". Therefore, since the winding 93 of the differential relay 63, alone 'carries current, the said relay be comes energized and attract-s its armature,

'which shifts thespring 187 out of contact with the spring 186', and places the springs ,191' and `192 in engagement. The disengagement of the springs 186 and 187 destroys the energizing circuit through the relay 36, and the-spring 103 passes out ofengagement with the spring 189 rand into contact with the spring104, which removes the said shortcircuit froin the rotary relay 49 andvvind- `ing 106, establishing an venergizing circuit instead extending from xthe` substation ground G"through the release springs 32 and33 to the rotary line conductor 91,relay 49, winding 106 of the differential relay 63',"

tln'ough thesprings 103 and 104 tothe batter); lead 94,'thence through battery ll and to ground G. The rotary relay 49 now operates and the sprngs 193 and 194 come into Contact, whereby an energizing'eirouit is established through the releasemagnet 51 of the selector (l. inpassing through the winding 106, as above stated', aids the winding 93 in maintaining the springs 191 and 192 in Contact. The

energizing circuit through the; release mag-- net51 extends from ground @2te the springs 193 and 194;! release magnet 51, springs 191` and 192 to the battery lead 94, and through However, the current `now battery to ground G. rllhe release magnet energizes and remains in readiness to release cuit is broken. Both the vertical and rotary line relays47` and 49 being energized simultaneously, the trunk line conductors 113 and 114 leading to the sub-central station become grounded simultaneously over circuits previously pointed out. The grounding of the rotary trunk conductor 114 produces a short-circuit of the rotary line relay 7 5 `in series with theI winding 153 yof the differental relay 88 .extending kfrom ground Gr7 tof the contact point 161", side switch Wiper 85', springs 186 and 154, winding 153`of the -differential relay 88, rotary line relay to` the rotarytrunk conductor 142, shaft wiper 72, Wiper 135, rotary trunk` conductor 114l and to ground G2. Therefore, since the winding 146 of the differential relay 88 alone carries current the said relay becomes energized and attractsits armature, which shifts the spring 165 out of contact with the spring 185 and,l into contact with the spring 164.

The `disengagement of thel springs 165 and 185 destroys the energizing circuit through the relay 89, and the spring 154 passes out of engagement with the spring 186 and into contact with the spring 155, which removes the said short-circuit from the rotary relay 75 and winding 153, and establishes an enerwizing circuit instead extending from ground 2 at the selector C to the battery lead 126' and then to ground G', as explained. The

` rotary relay 75 now operates and the springs 195 and 196, release magnet 87, springs 164 y and 165 to the battery lead 126, thencethrough battery B and to ground G. Vhen the connector release magnet 87 is thus supplied with current it 'energizcs, and

' the selector switch when the energizing cirsofi as a result the switch-shaft and side switch y l are restoredfto normal positiointhus bre-ak,- inggthe connection between the connector `switch-,shaft wipers 76; 77fand" 78 .and the normal cond'uctors158, 159 and 160. The back-release relay 69- of the selector F being in the sameecircuit with the release magnet cnergizes simultaneously with the'latter, and opera-tes to closea circuit through the selector release magnet 68 by pressing; the backrelease springs 198' and'199together, The circuit through the saidV release'magnet 68- stored.

extends troni ground Gl through the springs 198 and 199 to the release magnet (55, therme to the battery lead 126 and through battery llto ground G. W hen the ground to the line conductors 90 and 91 is interrupted all the magnets involved in the release are deenergized and all the switches are fully re- 1t.v will be understood, of course, that when the connector switch l) is released and the wipers 76v and 77 disenga-ge from the normal conductors 158 and 159.,.the backbridge relay 89 oi'f the connector D is re-,

stored and the spring 15d-,controlled by said relay returns into normal engagement with the non-grounded battery spring 155, thus cutting orf talking battery/,current iirorn the calling line. Il: the called` lineplt2209. is busy at the t'rne that the calling subscriber .#5000 attemptsto establish connection, the

f connector D `is released by the last impulse to the rotary trunk conductor 11d as itollows: 'l'he said' impulse energizes the rotary line relay 750i? the connector l), which relav in turn energizes the private magnet 82, pie-ssing the private springs 299 aml2G1 into contact after the private wiper 78 has been carried onto the grounded privatevbanlr contact. Of course, itis understood that whenever a line is busy the connector private bank contacts connected with the private normal 160, shown at theselector E, are all connected to ground. Therefore, since the connector side switch is in second position, when the private springs 290 and` 201 are brought into contact an energizing circuit is established through the releasemagnet 87 irorn the said grounded private bank contact to the private wiper 78',.thence to the side swtch `wiper 85 (which is in second position), to the private magnet springs 200 and 201, to the release magnet-87, springs 16% and 165 to the ,battery lead 126, thence to batteryli and to ground GC The connector s itch-shalt and side switch are thus released in tlie manner disclosed in the said` connector patent, and connection is not es` tablished wth the called line, Anor is there anyliabi'lity of the back-bridge relay 89 energizing, thus makingv it impossibleI for the calling line to receive talkingbattery current. The busy signa-l is established when thesul'izuariber presses his signaling button 2b, aliter he has completed the calling oper ations. and,ot course, after the connector is released, as described. The connector side switch being in first position, as explained, when the vertical lineconductor is grounded by pressing the signaling 'button spring 29 onto the ground contact 31, the connector.'

vertical line relay 74C 'is then 'energized as before. Therefore, the line relay springs 14-7 and 148 are brought into contact, and the vertical magnet 79 is operated to raise the switch-shaft, whereby the ott-normal springs 202 and 208 are brought int-o contact and a busy signaling currentis sont to the callingsubstaton Yfrom the busy coil l through the springs 203 and 292 to the side switch wiper 841, ringerrelay springs 166 and 167, condenser 218 to the rotary trunk conductor v114, Condenser 61 of the switch C to the vertical line conductor 90, thence through the primary winding 5 to the rotary line conductor 91, and through the condenser 62 oi' the switch C tov the vertical trunk conductor 113, line relay 74 of the connector l), and winding 146 of the .differential relay 88 to thefbattery lead 126, and to the busy coil l, When the subscriber hangs up his receiver after receiving the busy signal, he grounds the line conductors 90 and 91 simultaneously, energizing the line relays of thev selector' C and connector' D simultaneously, asalready explained, thus producing the releasey of the y switching apparatus as liollo'ws i Y As soon as the vertical and rotary line conductors 90 and 91 are ground-ed, the vertical and rotary line relays l? and 19 and the differential relay 68 ot the switch C are energized,v whereby the line relay springs 193 and 194C are brought into Contact at the same time that the differential relay springs 191 and 192 are brought into contact; thus an energizing circuit is established through the release magnet 51 over circuits that have already been pointed out. At the same time the line relay springs 96 and 107 are, or" course, carried onto the ground spring 95, and as a result the trunk conductors 113 and 1.14 are grounded simultaneously, whereby the vertical and rotary line relays 74 and 75 and the differential relay 88 are energized simultaneously, causing the release magnet 82 of the connector D and the.,

back-release relay 69 of the switch F to be energized simultaneously.A As a result of the energizing oi the said release magnet the connector is released, as already eX- plained; buty the remaining` release circuits and rmechanisms are retained in readiness to perform the `linal releaseoperations as soon as the ground circuits are removed from the line conductors, at which time a release of' all switches follows in the inanner already explained. The selector C, in addition to establishing connectionv in a distant sub-central` may also be used` in establishing connections iu the local central ollice; thatv the subscriber at substationl A may call other subscribers whose telephone lines terminate inthe saine olice. ln that event the shaft wipers 89, l0 and l1 are raised and rotated into engagement with contacts of those bank levels in which conductors lead to selector switches located in the sarne ollice, one of which 'is diagrammatically shown at N in Fig. 1. I do not conine. niv improved selector switch (C to the exact location in a central oice shown in Figs. l and 2; for as shown in l? ig. 3 the callingy substation i is ma. have. alloted thereto a selector switch d of the type disclosed in said selectorv patent, and the selector C may beemployed as the second switch on the line from which the impulses delivered to theselector switch C are repeated (as explained) to the next switch, which latter may be in a distant subfcentral exchange, ormay bein the same local office as ktheselector C. lt will be understood that when the selector switchC is used in this manner the normal conductors 204, 205 and 206, shown in Fig. l, leading to the yselector C then lead `to the selector J, Fig. 3, since the latter is allotted to the line l#5000, and the selectors C are employed on a percentage basis-that is, to a group of one hundred first selectors there may be allotted a group of ten selector switches C; and, also, they trunk-release spring 193 which was formerly connected to ground then leads to the private wiper bank of the switch J and to other vbanks in multiple. As shown in Fig. 3, the selector switch {lcoinprises the vertical and rot-ary line relays 207 and 208 which receive battery 'current through the springs of the bridge-'cutoff relay 209. The said line relays are `adapted to operate the Vertical magnet 210, privatel magnet 211, and both relays acting' conjointly provide means whereby the calling subscriber may energize the release magnety 212 while the side switch wipers are in firstor second position. Asis well lrnown, the rotary magnet 213 imparts to `the shaft wipers 214, Lliand 216 their rotary or circular motion. The release relay 217 provides means whereby the selector may be released after connection has been established by `way of the shaft wipers ,214 and 215 with the next Y switch. As shown in said Fig'. 3, the selector J has `established connection with the selector C,iand the selector Chas in turn seized al trunk line which may lead to another central yotlice. Furthermore, the selector switch .may be operated to engage trunk lines which lead to other selector switches N, said selector switches being similar to the selectors F or C. Similarly7 the switch C is not conned tothe function of establishing distant trunking connections, but is adapted to perform the usual functions of selectorswitches. It will be noticed by comparing); selector J with selector F that another modification or special yfeature in the said switch F consists in the provision of two line relay release springs 219 and 220, so that if it becomes necessary to release a connection before the side switch of the said switch Fpasses to third position the release magnet 68 will be energized `directly by the operating of the linerelays (Stand 65, which relays upon thus operating press the said springs 219 thereof.l

and 220 into Contact, establishing a circuit` throughl` the release magnet 68 ,from ground i5 through the saidsprings` 219,*` and 220, and through the releasemagnet to battery.

The various `rela-ys may be ofany ,suitable resistance, but goed results "have been obtained when the vertical and rotary line relays 4,7 and 4:9, are wound tok aresistance of five hundred ohr-os each; the relayv 36 to a resistance ot tive hundred ohmsg'end the windings ot the differential. relay 63 .to a resistance of two hundred and fifty ohms each. A o

ln either embodiment of my. invention therefore, as shown in Figs. l and `3, proing' talkin current from the battery or other centralized source to the callingisubscribers line to charge the microphone transmitter lt will be seen,` of course, that these. relays also have more or less todo with they releasing` of thein allotted selector mechanism, in the manner explained. With such arrangement a pole-changing relay is provided for the calling subscriber, pas, for

example, in a combined iselector and repeater, and another pole-changing Vrelay is provided forgthe called subscriber,.as, for example'7 in the common battery connectorf. The current for charging thecallingsubscribers microphone transmitter is received through the line relays of a selector switch,

while the current for charging the kcalled subscribei"s microphone transmitter is received through the windings of a connector relay. Thus the combined selector and repeater C is adapted for the double function of selectively trunking and repeatingin one and the same direction` and is adaptedfor controlling' yand regulatingv the 'flow of talkingcurrent to the calling subscriber7 regardless of whether it is employed `inthe position `shown in. l, or in the manner shown in Fig. 3. In either case. ras erh plainechit will be seen that the calledy subscriber controls the operations by which the battery. is switched into the `bridge betweenl the two line relays of the said selector and repeater C to supply talkingn current tothe calling subscriberA The trunk-selecting and impulse-repeating :functions of ,the switching' machine Care however, controlledby the calling subscriber before the called subleo anyiautomatic switch mechanism for connecting with the other end of said trunk line, aline relay allotted to and controlling said mechanism, another line relay allotted to and controlling the said automatic switch, a circuit by which the first relay controls the second relay over the trunk line, a circuit for energizing the first relay to cause the said switch mechanism and automatic switch to be controlled rsuccessively thereby, a mo- Jcor magnet for said mechanism, a circuit for said magnet extending through contacts of said first relay, and means for operating said automatic switches by a varying number of impulses.

2. In a telephone exchange system, the combination of a calling telephone line, an automatic switch, an idle trunk line leading to said switch, a selector switch mechanism for extending connection from the calling telephone line to the said idle trunk line, a pair of line relays for controlling said selector switch mechanism and adapted to control the operations thereof, means by which the calling subscriber also employs said relays for controlling the operations of the said automatic switch, means for feeding talking current through the windings of said relays to the calling subscribers substation, a motor magnet for said mechanism, and a circuit fo-r said magnet extending through contacts of one of said relays.

`3. In a telephone exchange system, the combination of an idle trunk line, an automatic selector switch mechanism for making connection with said trunk line, a pair of line relays for controlling` said selector switch mechanism, an automatic switch responsive to said relays and forming the terminal of the other end of said idle trunk line, means for causing said pair of relays tio successively control the said switch mechanism and automatic switch, means for feeding talking current through the; windings of said relays to the calling subscribers substation, a motor magnet for said mechanism, and a circuit for saidy magnet extending through contacts of one of said relays.

4. In a telephone exchange system, the combination of trunk lines, an automatic trunk-selecting switch for extending connection over any one of said trunk lines, a pair of relays for controlling said trunksele-cting switch, an automatic switch at the ofl'lher end of each trunk line, each automatic switch being responsive to said relays after connection is made with the trunk line allotted to such switch, a calling subscribers impulse-transmitting device by which said relays are caused to successively control the said trunk-selecting switch and an idle one of said automatic switches, means for feeding talking current through the windings of said relays to the calling subscribers substation.y a motor magnet for said first switch Vand a circuit for said magnet extending telephone line, and suitable instrumentali-` ties for supplying talking current through the windings of said relays to the calling Subscribers line, and through the said automatic switch to the called subscribers line.

6. An automatic selector switch provided with a pair of line wipers, a pair of crossed or transposed line conductors permanently connected to said wipers, means including a relay for causing a step-by-step operation of said wipers; trunk line terminals adapted to be engaged by said wipers, automatic means for preventing the wipers from engaging the terminals of busy trunks, magnets by which a subscriber operates the said switch, circuits for said magnets independent of said line conductors, and switches at the end of said trunk Vlines adapted to be controlled by the said first relay.

7. The combination of a line, a plurality of trunks, a trunk selector in which Asaid line terminates, automatic switches in which the said trunks terminate, a pair of line relays associated with the said trunk selector` and adapted to control the trunk-selecting operations thereof, and means by which said relays are caused to repeat switch-operating impulses from said line to an idle trunk after a selection of the latter is made, a motor magnet for said trunk selector, and a circuit for said magnet independent of said line and trunk extending through contacts of one of said relays.

8. The combination of a subscribers line, a suitable trunk, switching means individual to said line for connecting with said trunk, a second switching means responsive to said first switching means and located at the end of said trunk, means for using said first switching means to operate the second switching means after the line and the trunk are joined together, means in said switching means to supply current for talking purposes, motor magnet for said first switching means, and a circuit for said magnet directly controlled by said last means.

9. ln a telephone exchange system, the combination of a calling telephone line, a called telephone line, means including a selector switch and a connector switch for joining the two lines together, a pair of line relays for the selector for Vcontrolling` the operation of said selector to extend a connection, a pair of resistance windings for the connector, two common batteries or centralized sources of'current supply, means for switching one battery in series betweentl'ic two windings yof thev selector relays toy sup ply 'current to the calling telephone line, and means for including the` other battery in series betweenthe resistance windings ot' the connector to supply talking current to the called telephone line.

10. inria telephone exchange system, a pair of condensers, a line having the two sides thereof terminating in said condensers, a pair of line wipers, trunk line terminals tor said wipers, a pairoifcrossed conductorsv connecting saidI condensers with said linev ywipers, a pair `of relaysbridged across the line relays, a trunk line having a terminal temporarily engaged by said line wipers, means operated by` the energizing or said pole-changing relay'tor switching the battery in seriesbetween the two line relays, and means 'or'supplying current over the said trunk liney and through the said wipers to energize said pole-changing relay.

12. In 'a telephone exchange system, the combination of a selector provided with a pair of line wipers and a pair of line con ductors suitably connected therewith, a polechanging relay bridged across the said line wipers, a `pair of line relays bridged across the said line conductors, a battery having one pole `normally connected between said line relays, a trunk line `having a terminal tem porarilyengagedby said line wipers, means,l

operated by the energizing ot said polechanging relay for switching the battery in series between-the two line relays, means for supplying current over the saidtrunlr line and through the said wipers to energize said pole-changing relay, and means by which a `called subscriber controls thefenei'gizing ot said pole-changing relay.

12%. 'An automatic selector switch compris-v ing a pair of line wipers, a pole-changing relay bridged across the said line wipers, a

iair oi' lineconductors suitablyconnected l .f

with' said line wipers, a pair ot line relays bridged across said line conductors, abattery having one polenormally connected between said'line relays, a differential relay havingl two windings'each of which is connected in serieswith one of the line-rel`ays, an energizing circuit for the pole-changing relay `controlled `bysaid diderent era-ted by the encrgizin ing relay tor switching the, in series between the-.windings-ot the differential relay and the line relays, a trunlrline temporarily seized by saidV line wipers, a'source of ei'iei'gizing current, and means 'for connecting said source oi? current with the other end ot' said trunk line to supply current backy through the said wipers and through the winding of the pcie-changing relay to operatively energize the latter. e

f '14. in a `telephone exchange system, the combination ot' a' caliing telephoneuline. a called telephone line, a `selector switch iicyided with crossed or transposed line c ductors, a connector switch by which t= "called telephoneiine is temporarily seized,

suitable trunk line connection between the two switches, relay means in the selector for controlling its own operations as well as i the' operations ott tl e connector switch, `and suitable instrumentalities or supply: talking 'current through the said relay. mea oi.' the selector switch to the"callingtele` phone line, and through the coiniector switch .to the called telephone line.

15. ln a telephone system, subscriber-s line, a plurality of trunk lines, a selector switch individual to said subscribei"sy line for selecting an idle one oi'said trunlr lines, and means in said .selectorswitch for repeating impulses over said trunks.

16. In a telephone system, al pilurality oit subscribers lines, a connector switch for connecting with a called line, a switch in` dividual to said called line, and a pole` changing relay' in said indii'iidual switch yadapted to be energized when said connector connects with the called line.

17. ln a telephone system, subscribeiAv line, an automatic switch individual thto, a' pair ot line relays bridged across line for controlling the operation `oit` switch, land a differential relay having winding connected in series with eachu of said linerelays tor controlling the release oiI said switch.

18. In a telephone system, a calling and a `called subscribers line. means including a selector switch operative in `accordance. with thefiirst digit ol the called numb i foi-'Tex` tending the connection `trom acalling to called line, a pair ot line relays tor said selector, a pole-changing relay for said relector, and ineansiior energizing said relay when the called subscriber answers for profl vidiiig talking current to the calling suh.

soribers line through said line relays.

19. In a telephone system, a'pluralityot subscribers lines,y means' including a' selec tor switch allotted to each of said lines operative in accordance with the 'first `digit o't thecalled number in establishing stalki... circuit betweena calling and a called subilo Cil

1, ribei.; relays in each or said switches 'for pplying talking current to the talking ci rcuit, a motor magnet tor each oit said switches, and a circuit tor each or said mag nets extending throughcontacts or one of the `associated relays.y l v 20. ln a telephone system, a plurality oi subscribers lines, means including iirst rselectors and second selectors for establishing a talking circuit between a calling and a called. line, relays tor controlling; said second selector, means for supplying talking current to sait hing circuit-through said relays, a motor magnet for said second selector, and circuit 'for said magnet entend-y ing through contactsv of one oi said relays.

21. ln a telephone system, a calling and called line, an automatic connector switch for connecting with a called line, a plurality oi.l switchesr tor extending' connection from calling line to said connector to thereby establish a talking circuit between a calling and a called line, relays for controlling one of said switches, means for supplying talking current to said talking circuit through said relays, a motor magnet for said switch,

and a circuit for said magnet extendingl through contacts' of one of said relays.

22. ln a telephone system, a plurality of subscribers lines, means including a` selector switch having line relays operative in aca x v E cordance With theiirst digit oi the called number for establishing a talking connection between a calling and a called line, and

, means for supplying talking current to the line through said relays when the called subscriber answers.

23. ln telephone system` a subscribers line, a combined selector and repeater provided with a ver ical line relay connected to battery at one side and permanently con nected direct to the subscribers line at the other side, a rotary line relay connected to Vbattery at one side and to the subscribers Y hist-selector and repeater provided with progressively movable step-by-step side switch` Wipers and line relay springs, said Wipers permanently connected directly to the line relay springs, respectively, and switching means responsive tothe same when used as a repeater.

25.' In a .telephonefsystein in which thev subscribers are divided into groups, means having one motion to select groups and an other motion to connect With the called lineV found in the selected group, a combined rst-selector and: repeater providedA With Vprogressively movable step-bystep side,

switch wipers permanently connected dir .1y to the line relay springs, respectively', and switching means responsive to the saine when used as a repeater.r

' 26. ln a telephone system in `ahicl'i the subscribers are divided into groups, means having one motion to select groups and an-v other motion to connect vwith the called line found inthe selected group, a combined selector and repeater for each subscriber, other switches whereby any subscriber may obtain connection with any other subscriber, a pair ot condensers in opposite sides othe vtalking .:ircuit, each said coi'nbined selector and repeater includin' apair of line shaft means rcontrolled by said relays -for then repeating` impulses over the seized trunk.

28. ln an automatic telephone exchange trunliing system divided into groups, a combinedhist-selector and repeater provided with side switch Wipers, and line relay springs, said Wipers permanently connect ed directly to the line relay springs, respectively, and switching means responsive to the same When used asY a repeater, said selector having one motion to select groups and another motion to automatically select an idle trunk in the selected group.

29. ln an automatic telephone exchange trunling system divided into groups, a combined selector and repeater for each subscriber, other switches whereby any subscriber may obtain connection with any other subscribe-r, a pair of condensers in opposite sides of the talking circuit, each said combined selector and repeater including a pair eli line shaft Wipers permanently connested with the subscribers line through said condensers, said selector having one motion to select groups and another motion to automatically select an idle trunk in the selected group, as set forth.

30. A telephone system, means ior establishing a talking circuit, comprising trimhr lines, an automatic trunk selector, a connector having vertical motion to select groups and rotary motion to connect with a line in the selected group, a called subscribers `telephone line adapted to be seized by' said connector, a calling` subscribers telephone line, a relayv individual to the calling l il() line to which,tliefselector land connector are sucres vely responsivesaid selectorrespon` sive tosaid relay viacirciiitsexcliided'trom said talking circuit, Asaid-relay associated with `and yincluded in said selector.

3l. l'npa telephonelsysteni, a calling ytelephone line, acalled telephone line, means including an autoii'iatic trunk selector for extending la talkingcircuit'tc thecalled telephone line, havingi.verti: al motion to select groups and rotaryniotion to connect with aline in the 'selected group, :said selector having` a controlling relay permanently connected `to thetalking circuit and operating magnets controlled over ycircuits excluding said talking circuit, `a source oi talking ciir rent, and means in said` selector responsive to the calledvsubsciibei toi ieeding talking current to the calling line.

di, telephone system, means for establishing a talking circuit comprising a truuk having an automatic switch at one :end thereof, lresponsive to-ealliiig iii'ipulses sent over said trunk, anda combined trunk sevlector and `repeater mechanism tor seizing y tliewotli'er end of said trunk, when the latter is idle, having means yior transmitting the said kcalling impulses to operate the said automatic switch, said mechanism comprising a. relaypermanently connected to `the (Y, circuit andoperating magnets controlled over circuits excludingsaid talking circuit. f

38. lira `trunl'nng system in `vvhich the talkin@ Avtrunks are `in, groups, means for establishing a talking `circuit comprising a ,trunk line ran automatic sivitch includinot a )air ot line relays to which the said trunk line leads,a second pairfof ,line relays connected to said talking circuit,ineans associated with saidsecond relays and controlled there 'by over circuits excluding said talking cir- `cuit for extendingconnection tolsaiid-t-runk line, elccti'oiiiagnetic,.means `ior said switch, i

and means by whichl a calling subscriber con'- ti'ols the energizingof said electromagnetic means through the medium ot said second relays, said switch having vertical motion f toselect groups and rotary motion to conneet withlthe, desired line in any predeter mined group.

34.1n a trunking system in` which the trunks are in groups, inea-ns for establishing motion toautomaticallyselect anidle trunk in any predetermined group. i

3 5. ,A te-lephOneeSyStem, vmeans tor estao-` lishingaftalking circuit comprising trunk lines, an autoiiiatictrunk selector, anwautd iiiaticsivitcli for eaclitrunk line, said trunk selector including a pairoil linek relays, and

`an automatic progressively movable Step-bystep auxiliary switch to ena-ble said relays to control the connector Aafter the selectorilias been operated,y the relays controlling the selector over circuits excluding the said talkingcircuit. f j y 86. ln a telephone system,a calling telephone line, a called l'telephone line, trunk linesconimon to said lines, a battery, an :iin-

pulse/sender in the calling line, an auto-v matic trunk selector forselecting anidle i one ot' said trunk lines to extend ,a talking circuit` toward i the called telephone line, operating'magnets for said selector, aiiiag net controlling relaygin lsaidsselector,` circuits for controlling `said magnets eizcliid ing the talking circuit, va sourceo'l talking current, 'and a progressively inovz'ible step-by-step electrounagnetically f controlled switch and a relay in said selector responsive currenttcthe calling line. i i

37. a telephone jsystemincludiiig a call` ing" telephone line, `directive switching means at the substation thereof, 'a directively controlled rstep-by-step seleetor'connected with said line, operatingrelays Vfor i said selector responsiveto said means, driving magnets for Aadjusting said selector' responsive to said*` relays, trunk circuit including a pairoi' individual trunk conductorsioiily,multiple contacts vat one endot `said circuitl at said selector and selectable thereby when said circuit is idle, .trunk relays connected Wit-h said conductorsat-the other end of said circuit, armature switch niechanism ol" therela-ys of` said selector conductivelyfcon'nected `with ysaid last-mentioned relays on selection made ot ysaid circuit, whereby thefrelays of said selector, operating' responsive to said substationvineans,

vto the called `subscriber "for feeding talking f,

directly control said trunk relays, and a ,i i

trunk selector for said circuit at said other end having operating electromagnets rcontrollable by said trunk relays.

38. A telephone system including a calling telephone line, directive switching means at the substation thereof, a selectorconnected With said line` operating relays for said se lector responsive to said means, magnets for adjusting said selector responsive to said relays, a trunk circuit including a pair of individual trunk conductors only, multiple contacts at one end of said circuit at said selector and selectable thereby when said cirf cuit is idle, trunk relays connected With said conductors at theiother end of said circuit, armature switch mechanism of the relays of the substation thereof, a selector connectedy with said line, operating relays for said selector responsive to said means, magnets tor adjusting vsaid selector responsive to said v'relays, a trunk circuit including a pair oit individual trunk conductors only, multiple contacts at one end of said circuit atsaid selector and selectable thereby when said circuit is idle, trunk relays connected with said conductors at the other end of said circuit, armature switch mechanism oit the relays or" said selector conductively connected with said last-mentioned relays on selection made of said circuit, whereby the relays of said selector, operating responsive to said substation means', directly control said trunk relays, a vtrunlr selector for said circuit at said other end having operating electromagnets tcontrollable .by said trunk relays, means for simultaneously energizing said trunk relays responsive to current impulses transmitted over said conductors by said selectorl relays when disconnection is desired, and a release `circuit of said trunkl selector operated responsivev to the simultaneous energization of said trunk relays. 40. A telephone system including a calling line, a directively controlled step-by-step selector` at the exchange having operating relays connected with, and responsive to directive currents over said line, traveling coritact-makers for said selector, a link-circuit havingtwo individual conductors only Jfor conductive connection to the contact-makers of said selector, said conductors being selectable by said selector responsive to said relays, link-circuit relays conductively connected with said conductors and operable responsive to currents transmitted by said operating relays on selection made, a selective switch for said link-circuit having driving magnets connected with armature switches of said link-circuit relays and operable thereby, and a release circuit for said switch responsive to' current changes produced at said selector in said individual conductors to release said selective switch when disconnection is desired.

41. In telephony, a trunk circuit for automatic telephone systems including a pair oi trunk conductors only, multiple terminals of said conductors, a. directively controlled stepby-step'selector at a iirst exchange for selecting said terminals, driving magnets for said selector and operating relays 'for controlling the same, trunk relays for said trunk circuit at an exchange at the distant end of said conductors, arma-ture switches ofsaid `operating relays conductively connected to said trunk relays when said selector selects said teiniinalswhereby said trunk relays are.

rendered directly controllable by said operating relays, a selective switch operable by said trunk relays,-and means for restoring said switch responsive to circuit changes produced in said trunk conductors at said selector. f

Signed by me at Chicago, Cook County, Illinois, this 11th day of January, 1907.

TALBOT e. MARTIN.

lVitnesses: f A

EDWARD D. FALns, ARTHUR B. SPERRY.

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