US1268069A - Automatic common-battery telephone system. - Google Patents

Description

ET D. FALES.

AUTOMATIC COMMUN BATTERY TELEHONE SYSTEM.

APPLICATIN HLED NOV. 5 T906- RENEWED SEPT, 19| '91T- 1,268,069. Patented May 28, 1918.

2 SHEETSWSHEET 2. 7.-

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UNITED STATES PATENT OFFICE.

EDWARD D. FALEB, O CHICAGO, ILLINOIS, ASSIGNOB, BY MESNE ASSIGNMENTS, TO

AUTOHAT ELECTRIC COMPANY, A CORPORATION 0F ILLINOIS.

AUTOMATIC COMMON-BATTERY TELEPHONE SYSTEM.

Speolnoation of Lettere ratent.

Patented May 28, 1918.

Application tiled November 6, 190B, Serial No. 342.959. Renewed September 19. 1917. Serial No. 191831311.

To all whom. it mmf emma-rn.'

Bc it. known t iat I, Row/inn D. FALns, o citizen of the United States of America, and resident. of Chicago, (look county Illinois, have invented a certain new and useful Improvement in Automatic Commonllatterv '.lolephone Systems, of which thc following` is a specification.

My invention contemplates an improve.- ment on the common battery telephone system disclosed in mv prior application Serial No. 336,353, tiled September 26, 1006,

'lhe ohjeet of my present'l invention is to `provide certain features of improvement, t et nils ot construction. eomhimitions ot" elements and circuit. arrangements tending` to improve the general etlieiency of an antomatie eonnnon battery teleihone exchange system, as well as to still nrther improve and simplil'y the connectors thereof.

To the tmegoinglr and other useful ends` my invention consists in matters hereinafter desorihed and claimed.

la the aeeompanyiiu;` drawings. Figure 1 is a diagrannnatic perspective view of one eniiaaliment of my improved connector.

Fig. 2 shows diagrammatieally a calling and a ealled substation (-.onneeted hy means ot a central olliee equipment., in a system embodying the prinei )les of my invention.

in the said otliee tie. calling lsubstation .#500 has allotted to it the first-seleetor (l ol' the. general type disclosed in United States Patent No. t-tll. issued March lll` ltltlt. to Keith` liriehson & liriekson. it will he seen that the eentral battery ll has its `osit-.ivo terminal preferably grounded at (i. The operating relays are.. as hereinafter e.\plained` normally eonnerted to the non-froumled terminal ol' the said hattery` so that the suhseriher hy grounding his line emulnetor may operatethe said switches. as is usually the custom in systems ol'4 this class. ln addition to the said lirstseleetor (l there. is shown mv im roved eonneet-.or switch 'D and another lrst-seleetor (1' allotted to the ealled lino. Also. at ifi is `shown n lalsy-signalin f machine. and at. l" a ringer generator is s town. Suhstation #500 is shown as having operated the eentral otliee switches and established eoinieetion with the substation #120. which is shown in its normal position. 'Ihe substation A may be of any suitable or approved type. rPhe one. in eonneetion with which I have elected to illust-.rate my invent-ion is an improvement. on the substation disclosed 1n United States Patent No. Llulh r rranted .Tune 30, itil-t, to Keith` Erickson and Erickson, and comprises a receiver t3, a switch-hook for controlling the suhstat ion circuits., which eonturollini.'` operations are accomplished through the medium of an suitable lneans` sueh as the eam arms 5, and 6. The said snhstat ion eomprises the usual transmitter 'i'. indnetioncoil 8 having the primary winding.r tl and secondary windinplt). the ringer ll` and condenser 12 in the ringer eirenit. Heine; an automatic substation it is provided with thc usual vertical and rotary impulse springs 13 and l-t and the release springs 15, 16 and 17, Said solist-ation is. of course` provided with a dial which is not shown hut. which is secured to the shaft. 18. together with the locking dog;` 19. Fiirthermom, there is a locking;` cam 20 that loeks the dop` 19, while the receiver is on the s\vitelihook` to prevent. a rotation of the dial. 'l`he suhstation ground circuit. is normally broken between the ground springs .ll and 3:2 hy the cani arm t; lint when said springs are permitted to engage. laronnd eonneetion is provided to the ground post' :ttl and to the release sprin r i7'. as is well known in telephones ot this type. ltor o nratinrir the impulse springs J3 and l-l tie substation is provided with an impulse wheel il secured to the shaft 18 that earries on its periphery the so-ealled vert-leal teeth .25 and one rotary impulse tooth 26. 'lhe said impulse teeth are so arranged that. when the dial is drawn down the impulse springs 14 nml 13 arc not carried into eontaet with the ground est. 23; hut as the dial returns the vertical teeth engaeo the vertieal impulso spring: 13. and a ter they have eompiet-ed their work the rotary impulse. tooth .tl o crates the rotary impulse spring: lvl. In t is operation the suhserilnn"s rertieal lino conductor .27 is tirst. I,fii'eu n numher of ground impulses alnl then the rotary line eondnctor 28 is iven one "round impulso. lt will lie notieed that. as lian: as the dial is out ol` normal position the eonstruetion is snrh that the dog lll permits the primary circuit sprin 29 and 30 to separate, thus preventing t e impulses that are delivered to either line conductor from passin to the other. The rin g device of su station A comprises a pus button 31 secured to the spring 32. In addition the springs 33 and 34 are so adjusted that when t e button 31 is pressed the springs 33 and 34 engage before the springs 32 and 33 disengage. Furthermore, it will be observed that when the button 81 is pressed and the springs 33 and 34 engage, the rotary line conductor 28 is then grounded instead of the vertical line conductor. Furthermore; the selector C and the selector C are identical and are of the general t pe disclosed in the reviousl mentioned atent No. 815,321. he only iiference between the selector C and the selector disclosed in said patent is that the selector C has two springs in series with the release relay and private wiper. These springs are so controlled Vby the release magnet that when the latter becomes energized its. armature operates to disengage the said springs, thereby disconnecting the release rela from the private wiper. The object of t is provision will be explained in connection with the release of the central oiiice switches. In the drawing both selectors are similarly represented. he line wipers and 36 and the private wiper 37, which are carried by the switch-shaft,-arc shown; also the side switch wipers 38, 392 40 and 41. In normal position the said wipers engage the contact points 42, 43, 44 and 45; 1n second position the contacts 46, 47, 48 and 49; and in third position the contact points 50 51, 52 and 53. The operations of the switch while a call is being made are, of course, controlled b the vertical and rotary line relays 54 an 55, which in turn control the vertical magnet 56, private magnet 57, rotary magnet 58 and release magnet 59. After the side switch passes to third position the release of the selector, as is well known, is controlled through the so-called back-release relayl 60. As soon as the switch 'is operated the switch-shaft permits the oil-normal springs 61 and 62 to come into contact, whereby a arding potential is established by way o the private normal conductor 63 to the private bank contacts of the connectors to prevent another subscriber from interferin with the line establishing connection wit the said line by way of the normal line conductors 64 and 65. When the oil-normal spring 61 is in normal osition, however, it rests in engagement with the spring 66, whereby the brdge-cut-ofl' relay 67 is retained in connection with the private normal conductor 63, so that whenever the line is called the said bridge-cut-oif relay 67 is enerized, whereby the line relays 54 and 55 are 66 isconnected from the battery and from The general mechanical details are very much the same, althou h the circuits are materially different. he usual switchshaft 68 of said connector is provided with the line wi ers 69 and 70 and the private wiper 71 w ich have allotted to their use the line and private banks 72 and 73. Said shaft is alsoY provided with the cam 74, lon 'tudinal teeth 75, circular teeth 76, norma post arm 77 and coil sprin 78. Said connector-switch is also provide with verso tical and rotary line relays 79 and 80 and the vertical and rotary magnets 81 and 82 and release magnet 83, rivate magnet 84, ringer relay 85, and the ack-bridge coil 86 which is composed of the windings 87 and 35 88. The side switch H performs the usual functions through the medium of the side switch Wipers 89, 90, 91, 92 and 93. The operation of the system ma be more clearly understood if each step uring a call is followed up in detail, as in the following:

It will be assumed that the subscriber at substation A wishes to call the subscriber at A', the number of which latter it will be assumed is 120. When the receiver 2 is 95 removed from the switch-hook 3 the cam arm 5, upon leaving the spring 94 which it normall engages, permits the s ring 94 to leave t e spring 95, thus brea ing the ringer circuit, and the same operation ermits the primary circuit springs 29 an 30 to come into contact. The first digit bein 1 the subscriber operates his dial accor ingly, and as soon as the dial is drawn down the ground s rings 21 and 22 come into 105 contact, estab ishing a ground connection from the substation round G' to the ground post 23. As t e dial returns, the

1m ulse wheel 24 thrusts the vertical impu se sprin 13 against the ground post 23 110 once, and t en thetrotary im ulse tooth 26 in a similar mannercarries t e rotary impulse s rin 14 onto the ground post 23 once. he e conductors 27 and 28 are, therefore,`each grounded once, and as a result the vertica 4line relay 54 of the selector C is first energized by a flow of current from the substation ground G through the ground springs 21 and 22, to the vertical impulse s ring 13, thence to the vertical line con uctor 27, side switch wiper 38, contact point 42, vertical line relay 54, bridge-cut-o relay springs 97 and 96 to the battery lead'98, and through battery B Vto ground G. The vertical line relay 54, upon ener izing, presses the line relay springs 99 an 100 into contact, thus energizing the vertical magnet 56 once by a i How of current from ground G2 through the springs 99 and 100, private springs 101 and 130 102 to the vertical magnet 56, thence to the battery lead 98, and from battexy B to lrround (i. The vertieallnagnet t5 thereore, operates to raise the shaft wi ers 35, 36 and 37 to the first level, in a wel -known manner. This operation having been aeeomplished, then when the rotary line conductor 28 is rounded the rotary lino relay on is energize and this in turn operates the privato ina net 5T, which latter then tri s the side switch to second osition, estrablis iing an energizing circuit tirongh the rotary magnet 58 for rotating the wipers onto sonne trunk line. The energizing circuit through the said rotary line rela 55 extends `from the substation ground i to the ground post 28, thence to the rotary impulse sprin 4, rotary lino conductor 28, sido switc i wi er 39, contact point d3, rotary line relay 55, rid e-cut-ol relay s wings 103, tl'i' and 96 to the iattery lead 98 tiience through hattery ll to ground (i. 'i`he said rotary lino relay upon pressing the spring lll-t onto the spring 99 closes an energizing circuit through the private ma net 5T, as aiready stated, from ground (1 through tho springs titl and 10i to the said )rivale magnet: 5i. thence to the battery cad 98 and through battery B to ground (l. The private magnet upon operating permits the sido switch to pass to second position, at. which time the side switch wiper l0 engages the grounded contact point i8, whereby the euergizing circuit for the rotary magnet 58 is closed lroin ground (ii to the contact point iH. side switch wiper it), interruptor springs |05. rotary ma net 5S to the battery lead 9S. thence througi battery B to ground (l. 'lhe rot-ary magnet is then energized. and the wipers 3?. :ttt and 3T are carried into engagement with the lrst trunk. lt the said trunk is not iulsy. the armature ol' the rotary muguet 5H. as is well known. hy nicchanieally operating the armut-ure of the private magnet 5T, releases the side switch to third position: hut il' the said trunk is husy the privato magnet'. energizes at the same time thatI the private armature is depressed and at. the instant that the privato wiper 37 engages the grounded contact'. so that the .side .switch is held in second position and un energizing circuit is maintained through the rotary magnet 58 until the private wiper 37 is carried onto the terminal ol' au idle trunk and tho energizing circuit'l |`or the private magnet destroyed. .'\l the suino `instant the side switch. of course. passes to third position and the wiper itl leaves the contact; point i8. thus breaking the energizing circuit l'or the rotary magnet .GH and bringing the selector to a stand- Istill. 'lho passage of the sido switch to third iosition carries the side switch wi ers :its an :itl onto the contact points 5t) antltil. and the line cominci-ors 27 and .28 are placed in connection with the line wipers B5 and 30 whieln'having already entered into connection with the trunk conductors 106 and 107 that lead to the connector l), place the said conductors 27 and 28 in connection with the said connector l). The passage of the side switch to third ostion, furthermore, establishes a guar in potential at the private wiper ti'i' when t lo side switch wiper -tl engages the grounded contact point 53. 'This guarding potential arrives at, the said private wiper 3T from the ground (l to the contact point titi, through the wiper Ytl bach-release relay titi, s wings 16:2 and 16: to the private wiper 37, tuts protecting tho trunk conductors 106 and 10i from heilig seized for the time being. The line conductors 9T and 28 having been thus extended to the conductor D the succeeding impulses from the substation A are directed to said connector D. The second digit being 2 the subscriber operates his dial accordingly, groundingr the verticali line conductor 2T twice and the rotary line conductor 2S once, as ulread' explained. llach time that the vertical lino conductor is grounded the verl ical line relay Tt) of the connector l) is euergizcd by n low of current from the sulistation "round G' to the vertical line conductor 2i', tronco through the selector side switch wiper 33 to the contact point 50, vert ical line wiper 35, vertical trunk conductor 10G to the vertical line relay 79, thence through said relay and through the side switch s winer Utl contact point 10S to the hatt-cry lead tibi, and from battery l5 to ground G. 'lho vertical line relay 75h eac-h time that it attracts its arnniture. lorces the line relay springs ltlt) and il() into contact. sending an impulso each time through the vertical magnet ril l'rorn ground ti through the said springs tuti und llt), conductor ill (Fig. l). privato springs ll. and liti. conductor il-l` sido switch wiper liti. contact point; lili to tho vertical magnet Si, thence to batter lead HH, and through haltery li to ground (i. .\s disclosed in the aforesaid patent the vertical magnet when energized operates to raise the swilcleshull und wipers. 'l`he vertical mugnet Hi heing ener *ized twicethe wipers (it), T0 und Tl are raised` to the second level. '.lho ground im misc to the rotary line conductor :23. after t le switch-shaft 11H has thus heen raised. energizes the rot ary linz` relay Sti of the connector. which in turn operates to euergize the privato muguet Hi. 'lhe circuit over which the .said rotary line relay Ht) is energized extends from the suits-lation ground tl to thc rotary line conductor 2s, thence to the side switch wiper :iti of the selector t. contact point hl, rotary line wiper titi. rotary trunt conductor itl? to tho said rotary liuc relay Sti, thence, to hatten-y lend tti. und through liattery li to ground (i. 'llu` rotary line rc ay Htl. upon attracting its armature, forces the ring 116 onto the spring 109, whereb a ow. of battery current is sent throug the private magnet 84 from ground G", through the springs 109 and 116, conductor 117 to the private magnet 84, thence throu h conductor 118 to the side switch spring 9 contact point 108 to the battery lead 98, thence through battery B to ground G. The private ma et 84, upon attracting its armature and t en denergizing, operates, of course, to release the side switch H from first to second posltion. The effect of the shifting of the side switch is to substitute the rotary magnet 82 for the vertical magnet 81, bringing the former under the control of the vertical line relay 79 when the side switch wiper 92 leaves the contact point 115 and engages the contact point 119. The side switch is so constructed that the wiper 93 engages the contact point 108 when the side switch H is in Iirst and second poistions. The contact point 108 is connected with the battery lead 98 and the contact point 120 is connected with the private wiper 37 and, consequently, with ground, when the connector is engaged. With a side switch wiper such as 92 there is a possibility that the wiper might overlap the contact points 108 and 120. Accordingly, to meet this possibility, the wiper 93 is twisted, as shown, and the contact made by the said wiper with the said contact points, instead of being a sliding contact as is the case with the wiper 92, is like the make-and-break contact between the ordinary relay contact springs. The third digit being 0, when the vertical line conductor 27 is grounded ten times corresponding to the digit 0, upon the operation of the dial the vertical line relay 79 then energizes ten times over circuits that are now known. Said relay 7 9 in turn causes the energization of the rotary magnet 82 step-by-step. The energizin circuit through said rotary magnet extends from ground G through the line relay springs 109 and 110, conductor 111, private springs 112 and 113, conductor 114, side switch wiper 92, contact point 119 to the rotar magnet 82, thence through battery lea 98, and through battery B to ground G. The rotary magnet 82 bein energized ten times the shaft 68 is rotate ten steps, in a manner disclosed in said patent, whereby the wipers 69, and 71 are carried into engagement with the tenth terminal of the second level, from which terminal lead the normal conductors 123, 124 and 125 that extend to the selector C of the called line, the former two of which conductors continue through to the called substation #120. After the connector has thus been operated the ground impulse to the rotary line conductor 28 energlzes the rotary line relay 8O of the connector over circuits that are already `well known, which relay in turn oplerates the private magnet 84 as bef fore. he said private magnet upon energizin if the line is busy, will close a circuit t rough the release magnet 83 that will release the switch; but it will be assumed for the present that the line is not busy and that the side switch H passes to third position when the private magnet 84 deener 'zes As soon as the side switch passes to tiird osition a guarding potential is cstablishe at the private wiper 71, when the side switch wiper 91| en ages the grounded contact point 126. T is guarding potential prevents any other subscriber fromca ling in on the-line #120 for the time being. This guarding potential, furthermore, sends a flow of current through the bridge-cut-o' relay 127 oi. the selector C for energizing said cut-oli' relay from the private wiper 71 to the private normal 125, thence through the switchshaft springs 128 and 129 to the bridge-cutoff relay 127, thence to the batter lead 98, and through battery B to oun G. The said relay 127 upon energizing separates the springs 130, 131 and 132, disconnecting the line relays 133 and 134 from the battery lead 98 and from each other. The side switch wiper 93 upon passing to third position engages the point 120, which changes the polarity of the conductor 135 from batter to ground, thereby completing a circuit w ich givcs battery current to` the Acalling subscriber for talking `purposes. This circuit extends from groun G* at the selector C, through the side switch wiper 41, back-release relay 60, springs 162 and 163 to the first-selector sha t wiper 37, conductor 136, contact point 120, side switch wiper 93, conductor 135, vertical line relay 79, trunk conductor 106, shaft wiper 35, contact point 50, side switch wiper 38, vertical line conductor 27, springs 30 and 29 to the springs 32 and 33, transmitter 7, primary windin 9 of the induction-coil 8, rotary line con uctor 28, side switch wiper 39 and contact point 51, shaft wiper 36, trunk conductor 107, through the rotary line relay to the battery lead 98, thence through battery B and to ground G. This talking battery current in passing through the line relays 79 and 80 energizes said relays. The said relays 79 and 80 upon energizing operate to close in contact the springs 109, 110 and 116, and the springsv 137 and 138, and to disengage the springs 138 and 139. When the springs 109 and 110 engage an energizing circuit is closed through the ringer relay extending from ground G through the springs 109 and 110, conductor 111, private magnet springs 112 and 113, conductor 114, side switch wiper 92, contact point 146, conductor 147, through the ringer relay 85 to the battery lead 98, thence through battery B and to ground G. The ringer relay upon energizing shifts the springs 165 and 164, through the release magnet 59 to the battery lead 98, thence through battery B and to ground G. 'lhe release magnet 59 upon energizing attracts its armature, which discngages the springs 162 and 163, thus breaking the energizing circuit; through the release relay 60 and the release magnet 83, whereby the armature 166 resumes its normal position and releases the connector. The release relay 60 also deenergizes and the springs 164 and 165 disengage, thus destroying the energizing c ircuit through the release magnet 59 which now operates in a Wellknown manner to restore the first-selector C. It will be understood that the release mechanism of the connector, comprising the release magnet 83, release armature 166, release link 140', double dog 158, is the same as that disclosed in the selector patent cited-that is, when the release armature 166 is attracted the link 140 latches the double dog 158, and when the release magnet 83 denergizes, the double dog 158 is then withdrawn from the shaft 68, which latter falls to normal position, and the said double dog at the same time restores the side switch H to normal or first position through the medium of the double do releasin arm 159, as is well known. Wlen the re ease magnet 83 andthe backrelease rela 60 of the selector C energize in series, as escribed, the release ymagnet 59 of said selector C attracts its armature, which latter is provided with the springs 162 and 163 which are adapted to separate when the armature of the release magnet is attracted, as explained. It Will be evident that when the release magnet 59 ener gizes it causes a denergization of the connector release magnet 83 producing the release of said connector, and at the same time the denergization of the release relay 60. The latter then permits the deenergization of the release magnet 59, which magnetat once drives the selector side switch to first position, permanently destroying the trunk-release circuit by removing the side switch wiper 41 from the grounded contact 53, and there also follows a release of the selector switch-shaft, which breaks the connection between the selector C and connector D. As is Well known, busy lines are protected by guarding [potentials and if the called line appens to e bus when the private magnet 84 is energized or the last time, as already explained, the connector switch D will be released at the instant that the private springs 167 and 168 are brought into contact, since the private Wiper 71 is then in engagement with the grounded contact. The release circuit extends from the grounded contact to the private wiper 71, thence to the side switch wiper 91, contact oint 169, private springs 167 and 168, reease magnet 83, conductor 177, side switch wiper 93, contact point 108 to the battery lead 98, thence through battery B and to ground G. The release magnet 83 upon en ergizing releases the connector switchshaft and side switch, as is well known, and, of course, the release circuit is broken as soon as the private wiper 71 leaves the grounded contact point. The subscriber at the callin substation then, upon prcssin r the signaling button, receives a busy signal-` ing current from the busy machine E, over the conductor 171, normal sprin fs 172 and 173, ringer relay springs 174 an 175 to the vertical conductor 176, condenser 160, trunk conductor 106, shaft wiper 35, side switch wiper 38, vertical line conductor 27,' springs 30 and 29, through the signaling device, transmitter 7, primary winding 9 of the induction-coil 8, rotary line conductor 28, side Switch wiper 39, switch shaft wiper 36, trunk conductor 107, through the rotary line relay 80 to the battery lead 98 and back to the bus signaling machine E. The subscriber wil then hang up his receiver, grounding both line conductors 27 and 28 and as a result simultaneously energizing the line relays 79 and 80 of the connector D, thus bringing the springs 137 and 138 into contact. An energizing circuit is established through the release magnet of the connector in series with the release relay of the firstselector C. The energizing circuit extends from ground G4, as previously traced, to the shaft wiper 37, conductor 136, through the trunk-release springs 137 and 138, through the release magnet 83, side switch wiper 93, contact point 108 to the battery lead 98, thence through battery B and to ground G. The release of the central oiice switches is then brought about, as previously explained-that is, the selector C is disconnected from the connector D and the latter is fully restored; and if the subscriber continues to retain the release springs 15, 16 and 17 in contact for an extended length of time, then as soon as the selector side switch is drawn into first position by the dee'nergizaf tion of the selector release magnet the line relays 54 and 55 of the selector energize simultaneously over circuit that are known, again energizing the release magnet 59 by pressing the line relay sprin s 99, 100 and 104 into contact. Of course, t e engagement of the line relay springs 100 and 104 energizes the private magnet 57, which latter connects the release magnet 59 with the line relay spring 100, and the enga ement of the line relay sprin 100 with t e ground spring 99 energizes t e release magnet 59, as is Well known. This energizing circuit through the release magnet is, of course, broken when the subscribers release springs 15, 16 and 17 separate. From the description of the circuits it will be seen that if the called subscriber hangs up his receiver beond motion to connect with a line in a se lect-cd group for extending connectlon to a called line, a grounded source of current, and' means operated by current from said source responsive to said device for ap lying signaling current to the selected ca led line, as set forth.

9. In a telephone exchange system, acommon battery connector having `vertical and rotary switching motions and signaling and releasingr and current-feeding operations, .a pair oi' line relays having complete and d1- rect control of all of said operations, and means for switching a battery in series with and between said relays, as set forth.

10. An automatic trunking switch provided with a trunk-release circuit, a release relay in said circuit, a release magnet controlling said circuit` a release magnet energizing circuit controlled by said relay, and means for supplying talking current over a portion of said trunk-release circuit.

11. In an automatic telephone exchan e system, a selector provided with a trun. release circuit, a release relay in said clrcuit, a release magnet provided with normally closed contacts controlling said circuit, a release magnet energizing circuit, said relay provided with normally open contacts controlling said energizing clrcuit, and means for supplying talking current over a portion of said trunk-release circuit.

12. In an automatic telephone exchange system, the combination of automatic switches, a talkin circuit, a trunk-release circuit between switches, and means for supplying electric current over a portion of said trunk-release circuit to the talking circuit.

13. A telephone exchange system provided with subscribers lines and release trunks, and means for supplying battery current over the release trunks to the lines for talking purposes.

14. In a telephone exchange system, the combination of a release trunk, a release circuit, a telephone, a tele hone circuit, and a source of current, sai circuits including said release trunk and source of current.

15. In a telephone exchange system provided with subscribers lines and selectors and connectors, whereby talkin circuits are established between calling an called subscribers, means for supplying batter current through selectors and connectors y devices therein not included in the talkin circuits, and then over said circuits to cling lines and also to called lines.

16. In an automatic telephone exchange system provided with subscribers lines and automatic connectors means under the con- :nl of the callin subscribers for supplying talkl current rough the connectors to the ca ling lines, and release trunks over which the talking current is supplied.

17. In a telephone exchange system, a subscribers telephone, a selector aprovided with a private wiper, a source of t current and a circuit including said telep one and private wiper and source of current in series.

18. An automatic telephone system comprising a connector provided with a release magnet, a side switch, a couple of ener 'zing circuits for the said release magnet, eac circuit comprising a iirst and second switch point, each of said energizing' circuits havmg one of the switch oints thereof open and the other closed whlle the magnet is deenergized, the open switch point of the rst of the said energizing circuits being provided by a p-air of springs, and the open switch point of the secon of said energizing circuits being provided by a second pair of springs, and means for operating said springs, the closed switch points for the said circuits being provided by the springs of the side switch, as set forth.

19. In a telephone system, a trunk line, a trunk-selecting switch for selecting said trunk, a single-wound release relay therefor controlled over said trunk, and means for supplying current through the windin of said relay to the talking circuit for tal 'ng purposes.

20. In a telephone system, a trunk-line consisting of a tpair of talking conductors and a third con uctor associated therewith, and means for supplying current over the third conductor to one of the talking conductors for talking purposes.

21. In a telephone system, a trunk-line consisting of a pair of talking conductors and a third conductor associated therewith, and means including said third conductor for bridging a common battery between the talking conductors of the tru -line.

22. In a telephone system, a battery, a telephone line, a connector common to the system, an individual trunking switch for said telephone line, and means including portions of said individual switch constituting a battery bridge across the talking circuit at the connector.

23. In a telephone system, a connector having one motion to select oups and another motion to find the ca ed 11ne in any selected group, means including an automatic trunk selector for extending a trunk side switch whereby in its final osition the said current source is connecte to supply talking current to the calling line.

25. In a telephone system, subscribers lines, means including a final connector switch controllable over a calling line for extending a connection to a called line, a central source of talking current connected in bridge of the calling line upon the completion of the connection and before the called subscriber answers, and a progressively movable side switch in said connector for closing said bridge.

26. In a telephone system, subscribers lines, means including a selector switch and a connector switch controllable over a calling line for extending a connection to a called line, release magnets in said switches, a release relay in said selector controlling the circuit of its release magnet, an energizing circuit including the said relay and the release magnet of the connector in series under the sole control of the calling subscriber, and means including a relay denergized responsive to the opening of the calling line for closing said circuit.

27. In a telephone system, an established connection between a calling and a called line including an automatic connector switch, a relay in said connector energized over the two sides of the calling line in series during conversation, a release magnet in said connector, a circuit for said magnet open at a single point under control of said relay, and means at the calling substation for opening the line at the termination of conversation whereby said relay is denergized to close the circuit of said release magnet.

28. In a telephone system, subscribers lines, means including a connector switch controllable by separately grounding the two sides of a calling line at the substation for extending connection to a called line, means for supplying current to the talking bridges at the calllng and called substations, and releasing means in said connector under the sole control of the calling subscriber and operative responsive to the opening of the talking bridge at the calling substation to release the connection.

29. In a telephone system, means for connecting a calling and a called line including an automatic connector switch, a relay in said connector energized upon the completion of the connection to close the talking conductors, a second relay energized over the two sides of the calling line in series, a source of signaling current, means at the calling substation for denergizing said second relay and circuit connections whereby upon the denergization of said second relay the said first relay is denergized to connect said source with the called line.

Signed by me at Chicago, Cook county, Illinois, this 1st day of November, 1906.

EDWARD D. FALES.

Witnesses:

ARTHUR B. Srmr, Hammam* M. MERRIAM.

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