US1345054A - Automatic telephone system - Google Patents

Description

B. D. WILLIS. AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED APR.8.1914. RENEWED AUG. 1, 1918. 1,345,054, Patented June 29, 1920.

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AUTOMATIC, TELEPHONE SYSTEM.

APPLICATION FILED APR. 8. I9I4. IIENEwED AUG. I. 191s.

1,345,054. 'Patented June 2.9, 1920.

2 SHEETS-SHEET 2.

ffl 3 IIIIIIIIIIIIHII' UNITED STATESA :PATENT OFF-ws BERNARD D. WILLIS, 0F CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, AOOB'PORATION ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

T 0 (ufl whom t may conce/rn.'

Be it known that I, BERNARD D. WILLIS,"

a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented certain new and useful y means for controlling automatic switcheswhich include plurality of operating magnets, together with means for successively switching the operating magnets into operative position, which operating or motor magnets are controlled by impulses of one character, while the switching operations are controlled by impulses of a different character.

In the accompanying drawings I have illustrated my invention in connection with automatic selector and connector switches of well-known types, and while I have shown but a single selector switch for extending connection to the connector, it will, of course, be understood that second selectors controlled in a manner similar to that of the first -selector could'be inserted between the first selector and the connector. In the drawings Figures 1'and 2 taken together show a complete'circuit connection between a calling substation A and a called substation A in a system embodying the principles of my invention.

Fig. 3 is a view showing a portion of the impulse-transmitting mechanism. l

Referring to Fig. 1, there is shown a subscribers substation A, the line conductors of which terminate inthe individual or line switchC. This line switch is one of a group of similar line switches, the plungers (not shown) of which engage a shaft and are controlled by the operation of the master switch D in such manner that they are, when in normal position. held directly in front of the terminals of an'idle trunk line leading to a selector E. The selector E is the means for extending the connection to Specification of Letters Patent. l kvPai-,enilnl une 29, 1920, Application filed. April 8, 1914, Serial No. 830,399. RenewedAugust 1,v 1918. Serial No. 247,862. v

scribers'line A. c l

The subscriber-s substation Amay be of any suitable or approved type and comprises the usual receiver 2, transmitter 8, ringer 4 and condenser' 5. It is also provided with a suitable impulse-sending device similar to that shown and described in British Patent No. 29,654 of 1910, issued to S. G. S. Dicker, except that two-extra impulse springs are added, together with means for controlling the same. Referring Yto the substation A, the impulse-sending device comprises a pair of impulse springs 6 and 7, apair of auX- iliary impulse springs 9 and 10 and an impulse wheel 8, whichv latter is controlled .through the medium of a finger hole dial fthe connector switch II (Fig. 2), which4v completes the connection to the called sub- (not shown) in such a manner that the impulse springs 6 and 7 may be momentarilyl separated a number of times corresponding to the digit called to transmit a plurality of impulses over the line, and which impulses are then followedby one or more rapid impulses transmitted by the impulse springs 9 and 10. Referring to Fig. 3, a pawl 12jis securedvto therotatable portion 11 of the dial, one end of which pawl is held in normal position against the pin 13 by a spring 14. When the dial-is rotated in a counter-clockwise direction, the pawl v12 strikes the, spring 10 in such a manner as to tilt the said pawl downward, thus allowving it to pass the spring 10`without causing it to 'break Contact with the springV 9; but

when the dial is released and the rotatable portion 11 rotates back to normal, one or more impulses are transmitted over the line conductors by means of the impulse springs `6 and 7; then, just before the dial Vhas returned to normal position, the pawl 12 engages the spring 10 (as shown in Fig. 3)

.and iexes it to the right until the pawl- 12 has passed beyond the said spring. The instant the pawl 12 releases the spring 10, it flexes to the left. and separates from the spring 9, sending one or more quick or high frequency impulses. It is, of course, understood that any suitable dial or call-sending device may be used and that I do not wish to limit myself tothe exact construction shown herein.

. rvThe subscribers individual switch C is of the general type of subscribers switch shown` in Britishpatent to R. W. James No.

' "eral 'type of Yselector switch disclosed in ing to a selector switch E. Each trunk line' 26,301 of 1906, being, however, of the particular type shown in British patent to T. Gr. Martin No. 1419 of 1910. This line Y so constructed that -the magnetic circuit of the windings 18 and 19 is separate from that ofthe windings 20 and 21. AThe winding 18 operates both theplunger arm 15 and the cut-off armature 16, while the winding 19 is only strong enough to operate the cutp' armature 16 and to hold the plunger arm 15 in its operated position. Vhen the plunger arm 15 is operated, the plunger is forced into a bank of contact springs, forcing the springs 23, 24, 25 and 26 into engagement with the springs 27, 28, 29 and 30, respectively. VAlthough Vonly one set Yof springs (23-30) is shown, each line switch is provided with a plurality of such sets, eachset forming the terminal of a trunk line leadjis connected in multiple with the corresponding springs of all the line switches ofl function of the master switch, as is well kn'own,ris to maintain the plungers of all the idle line switches 1n positlon to engage the terminal `of an idle trunk line.

The first selectorswitch E is of thegen- United States Letters Patent No. 815,321,

lgranted luarch 13, 1906, to Keith, Erickson and Erickson, except vthat the so-called side y ries.

switch is omitted and the'circuits Vare modified to adapt the switch to operate in a system in which it is controlled by impulses delivered over the two sides of the line in se- Among other details, the seelctor E comprises a bank of contacts arranged in rhorizontal rows or levels, which contacts are y switch are .controlled through the medium of 'the double-wound line relay 36. Means Vfor permitting the switch to be restoredto normal position is provided in the release magnet 37, which, upon energizing, withdraws the retaining pawls from the shaft in the well-known manner. Springs 38 and 39 are also provided, which springs close only when the switch shaft has been raised one ormore steps from its lowest position. The circuit of the release magnet 37 is controlled by the relay 40, which relay is a slow acting relay, c., it is slow to energize when its circuit has been completed. The said relay will not respond to ordinary impulses of current, but requires a steady flow of current to operatively energize. When the line relay 36 energizes, it closes the circuit of the relay 62, which is connected in series with the relay 63. This latter relay, however, is normally short-circuited by the springs 41 and 42 of the line relay36. The spring 41 is so adjusted and constructed as to follow the spring 42 when the relay 36 is energized.

Should one or more impulses of ordinaryY duration be transmitted through the line relay 376, the springs 41 and 42 will operate in 42 will be separated for an instant due to the fact that the spring 41 is unable to follow the'rapid vibrations of the spring 42. The relay 62 also controls the circuit of a relay 88, and a switching relay 86 is provided for cutting the connection through to the wipers 31,32 and 33. The construction and operation of the switch will be hereinafter more fully explained in connection with the description of the manner in which a connection is established between a calling and a called line. I

The connector switch l-l (IF ig. 2) is of the same generalV type of connector switch as disclosed in United States Letters Patent yl\lo.,81' ,176, granted March 13, 1906, to

Keith, Erickson and Erickson, the circuits, however, being vnfiodilied to adapt the switch to operate in a system inV which .the central oiiice apparatus is controlled by impulses delivered over the two sides of the line in scries. Like the selector, the connector is provided with a shaft (not shown) carrying the wipers 45, 46 and 47, which shaft controlled by the vertical magnet 48 and the rotary magnet 49V which are in turn controlled bythe line relay 52. The usual side switch comprising the wiper 50 controlled by the private magnet 54 in the usual well'- known manner. The magnet 51 is the usual release magnet. The line relay 52 is con.- nected with the line through the reversing springs of the so-called back-bridge relay 53, through the windings of which latter relay the called line is provided -with talking current. The springs and 56 con trolled by the line relay 52 operate in the' there is shownk the battery B having one armature.

same manner as hereiiibefore described for termina-l grounded -at G. At Q there` is shown a busy signaling machine which pro` vides a busy signal, said busyL signal being applied to the calling line through the mediumo'f the busy relay 60 in case the called line is in use. i

The substation shown at A 'and' the line switch C are similar in all respects to the substation A and the line switch C'.

Having given a general description of Vthe apparatus, in order to give a clearerunder- Y standing of the operation of the system, it

will now be described inV detaill how the calling subscriber at substation A may obtain connection with the subscriber at the called substation A. We will assume that the number of the called substation is 220.

Upon the removal of the receiver at the substation A a circuit is closed through the line winding 21 of the individual switch C, thereby attracting the line armature 22.

The armature 22, uponxbeing attracted,`

closes a circuit through the'pull-down coil 18 in series with the auxiliary windingV 20. The pull-down coil, upon energizing, at-

tracts the plunger arm 15 to force the plunger into the bankof springs 23 to 30, inclusive. It also operates the cut-olf armature 16, thereby disconnecting the line winding 21 from the line, The armature 22 does not fall back immediately, however, owing to the fact that the winding 20 is still in series with the pull-down winding 18. Upon the plunger arm 15 being attracted, the

ysprings 61 are brought into engagement to short-circuit the auxiliary winding 20, making the same slightly slow acting. The armature 22 being slow to fall back allows suliicient time for aholding circuit to be closed in the switch rahead for the cut-off or holding winding *19.v The engagement oit the springs 23 and 26 with the springs 27 and 30, respectively, extends the subscribers line to the line relay 36 of the selector switch -The line relay 36 oi the selector switch E is thereupon energized,iclosing a circuit through the relay 62. 4The circuit extends from' ground G through the springs 43,

42 and 41, springs 64 and 72 of relay 63 throughthe said rela, 62 to the battery lead 100, thence throng battery B to ground G. The relay 62, upon energizing, closes the relay 88 extends `from ground the above-mentioned holding circuit through the cut-oil1 winding 19 of the "line switch C.' This circuit extends from ground G3 through the contact of springs 67, 66 and 65, springs70 and 69,'bank springs 28 and 24 and the said holding winding 19 to the battery lead 100. The winding 19, upon energizing, holds tlie.,arinatu1'e 16 and the plunger arm 15intheir operated positions after the circuit or' the pull-in`w1nding is 'broken by the falling back of the line arinature 22. Af guarding ground potential 4is supplied to the connector private bank con- Y tacts ofthe calling line as soon as the relay 62 is energized. the circuit justV traced to the .bank spring 24, thence over the conductorv 71 to said private bank Contact. A further result of the cnergization'of the relay 62 is to close a locking circuit for itself and` to close a circuit through the relay 88. The locking circuit `for the relay 62 extends from ground G3 through the contact lof springs 67 and 66, springs 73, springs 42A and 41, springs 64yand 72 and the said relay 62 tothe battery lead 100. The energizing circuit for G3 through the contact of springs 74 and 75 and the relay 88 to the battery lead 100. The relay 88, upon energizing, closes a locking circuit for itself `after springs 39 are closed, extending from ground upon the release trunk 77, springs 78, off-normal springs 39, springs and 81 and through the said relay 88 to the battery lead 100. The'apparatus is nowl in readiness to digit,

The calling subscriber now operates his calling device for the firstV digit 2 of the called number, whereby the substation impulse springs 6 and 7 are separated twice,

receive impulses for the first followed by one or more high speed impulses transmitted by the impulse springs 9 and 10. The line relay 36, responding to the two impulses sent by the impulse springs 6 and 7, denergizes twice, which operation transg mitsv two impulses of current through the vertical magnet 34.v The circuit for these impulses extends from ground G4 through i the contact oi'springs 83, springs 84,.springs and the said vertical magnet 34 to the battery lead 100. It will be seen that the relay 40 receives impulses at the same time, but it is not operated, as it takes a steady flow of current to operatively energize the said relay. The vertical magnet, receiving the two impulses over this circuit, operates to raise its switch shaft and wipers two steps opposite the second row or level of bank contacts. The high speed impulses which ol low the two impulses just transmitted by the impulse springs 6 and 7 cause the armature of the line relay to vibrate very rapidly. As hereinbefore stated, this causes the This circuit extends 'overY`v springs 41 and 42 to be separated for an in- 130 41 and 42 come to rest.

stant, which causes the relayv 63 to be operthrough the contactof springs 67 and 66,

. springs 73, relay y63 andthe relay 62 to the battery lead 100. The relay v63upon energizing, opens the shunt around itself at the springs 72V and64, `thus preventing it from again becoming shunted when the springs A further result due to the energization of the relay 63 is to close a'locking circuit for itself, shortcircuit the relay 62 and place a new holding ground upon the trunk-release conductor 77. The said locking circuit for the relay 63 extends from ground G. through the contact of springs 43fand 42, relay 63 and the springs 72 and 71 to the battery lead 100. The short-circuiting of the relay 62 causes the same to denergize, thereby closing a circuit through the rotaryl magnet 35. This circuit extends from ground G5 through the contact of springs 68 and 69, springs 78, off-normal springs 39, springs 80 and 81, springs 75 and 76, springs 79 and the-said rotary magnet 35 to the battery lead 100. The rotary magnet, upon `energizing, rotates the Wipers one step, and by opening the springs `79 and 78 disconnects ground G5 from itself and from the relayy 88. It the first trunk line of the second level is idle, the relay 88 denergizes immediately, but if this trunk line is busy, the private wiper 32 inds the contact with which it engages provided with a guarding ground potential which istransmitted to the relay V88 through 'the springs 80 and 81, thereby preventing it from denergizing. The rotary magnet, however, denergizes when the` springs 79 disengage, regardless of whether the relay 88 remains energized or not. If the relay 88 remains energized, the circuit of the rotary magnet will be again closed as Vsoon asthe armature drops vback far enough to close the springs 79. The rotary magnetwill therefore operate in the manner of a buzzer to advance the wipers step by step over the contacts until they nongrounded contact of an idle trunk line is reached by the wiper 32, whereupon the relay 88 denergizes. The relay 88, upon deenergizing, whether after one or several operations of the rotary magnet, permanently breaks the circuit ofthe magnet 35 and closes the circuit of theswitching relay 86. The circuit through said relay extends from ground G5 through the contact of springs 68 and 69, springs 78, off-normal springs 39, springs 80 and 482 and the said relay 86to the battery lead 100. The relay 86, upon energizing, extends the calling line through the wipers 31 and to the line relay 52- of the connector H and disconnects the line relay 36 from the said calling, line.

VrThe line relay 52, upon energizing, closes a circuit through the relay 87. This circuit 54 and to also prepare a circuit for the vertiextends from ground VGG throughV the contact of springs 57, 56 and 55, springs 89 and the lower winding of the relay.87.,to battery B. The relay 87, upon energizing, closes a holding circuit lor .the relay 86 of the selector@ and the holding winding 19 of the line switch G. The said circuit for the-relay 86 extends `from ground G7 through the contact'of springs 103 and 104, springs 93 and v94, conductor 91, wiper 32, springs 80 and 82 andthe said relay 86 to the batteryA lead 100. The holding .circuit for the holding winding 19 extends over the circuit just traced to the wiper 32, thence through the orf-normal springs39, springs 78, bank springs 28 and 24 andthe said winding to the battery lead l100. The adjustment of the relays 88 and 63 is such that the relay 87 or' the connector H will be energized and provide a holding ground 'for the trunk-release conductor 91 before the relay 63 denergizes. A further result of the energization of the relay 87 is t0 close a locking circuit for itself and'vfor the private magnet cal magnet 48 by the closureof the springs 95. The said circuit extends from ground G7 through the contact offsprings 104 and 103, Y and the springs 94,93 and 96. Here the circuit divides, one branch extending through the upper winding of the relay 87 to battery Y B, and the other circuit extending through the contact of' springs 97 and the private magnet 54 to battery B. The apparatus is now in readiness for the operation of the dial atv the calling substation for the second digit 2. lhe calling subscriber now operates his calling device for the second digit 2 of the called number, whereby the substation im- 105 pulse springs 6 and 7 are separated twice, followedby one orl more high speed impulses transmitted by the impulse springs 9 and 10. The line relay 52,.responding to the two impulses sent by the impulse springs 6 and 7, is denergized twice, therebysending two impulses through the vertical magnet 48. Thiscircuit extends from ground G6 through the springs 58, springs 95, .vertical magnet 48 and the side switch wiper 115 50 (in first position) to battery B. The relay 99 also receives impulses of current at this time, but it is not operated, as this relay does not respond to the impulses of Vcurrent. The vertical magnet being thus operated steps the switch shaft and wipers up two steps opposite the second row orlevel of bank contacts. The high speed impulses that follow cause the armature of theline relay 52 to vibrate very rapidly, which op- 125 erationgcauses the springs 55 and 56' to separate for an instant in the mannerV heretofore described, whichoperation allows 'the Vrelay 101 to energize. The circuit for this Contact of springs 57 and 56, relay 101 and'r the lower winding of the relay 87 to battery B; The relay 101, upon energizing, opens the shunt itroin aroiindfitsel'f at the springs t9 and opensthe circaiitoiE the private magnet ilat the springs 97. rllhe private magnet 51, upon deenergizing, allows the side switch to advance from first to second position. yThe movement` oi the side switch wiper 50 from vlirst to second position transfers the battery connection from the vertical magnet L18 to the rotary magnet49. The calling subscriber now operates his calling device lor the last digit 0, in response Ate vwhich the coiinector'line relay operates to transmit tenl impulses through the rotary r agnet L19 to battery B. The circuit of the.'

relay 101 'is opened upon thel irst denergization of the relay `The relay 101,Y

upon deenergizing, again closes a circuit through the private magnet 54 at the springs 97 and places a shunt around itself at the Y springs 89Q The rotary magnet, responding (saV to Vthe ten impulses transmitted by the line relay 52, operates to rotate its wipers onto the contact or the desired`-liiie.

ture ot the line relay152 to vibrate very rapidly, thus causing the springs and 50 `to separate 'for an instant, which allows. the relay 101 to again energize. The relay 101, upon energizing,V opens the shunt around itself at the springs 99 and opens the circuit et the private magnet 54'at` the springs 97. The private magnet A5&1, upon deenergizing,allows the side switch yto advance one more position, .je., from second to thirdposition. By 'the engagement of the side switch wiper 50 with its third-posi- 'tionV contact point, a circuit is closed eX-f tending ironi'ground G7 through the contact of springs 104 and 103, springs 93 and 9i, springs 106, relay 107, lower winding` oit tl'ieielay ,G0 and the iside switch wiper 50 'third position.) to batteryB. The relay does not receive sufficient-current when connes ,ed inserieswith the relay 107 to operativelyr energize. The relay 107v extends the calll through cut-oft winding 111 extends' from` ground Gllthrou'gh thecontact of springs 109 and 110, privateV wiper 4117, conductor 115 and thesaid eut-oil winding 111 to battery B.

.The ,circuitr'forythe ringing relay extends :trom vground G11 through the,V Contact of springs 109 fand 108, springs 116 and'119,

ringing relay 112-and the interrupt'er 117 to batteryB. 'The ringing-relay, upon energizing," disconnects the calling line from'` The high speed impulses .that follow cause the armarent generator 'R acrossthe .called line t0 signal the called subscriber.

the medium of the interrupter 117. Uponv the, response of the called subscriber his line is provided with talking current throughV the windings of the back bridgev relay 53, which relay, upon energizing, closes a cir-V cuit through the upper winding of the relay (30. This circuit extends `fromground G12 through thevcontact of springs 118, throughfthebupper winding of said relay and the side switch wiper 50` (in third position) vto battery B. The two winding of the relay 60 assist eachother and the said relay is operatively energized. The relay 60, upon energizing, opens the'circuitpof the ringing relay 112 at the springs 116 and 119 and closes ya locking circuit for The ringing relay is energized intermittently through itself through the springs 116 and 120 in# is completed, 'theA4 connection isreleased by the hanging up of the receiver. at the calling 'substation in the following manner: VVhen'tlie receiver at the substation A Ais restoredtotheswitchhook, the separation of the"hookswitch i Y springs destroys the energizing circuit ofthe connectorr line relay 52,. The line relay 52, vupon, denergizing, closes a circuit through" the relay 99, which relay is slow to energize.

The said circuit extends from ground G through the Contact of springs 58, oft-nor-` mal springs 121 and, the said relay 99 to bat-r tery The relay 99, upon energizing, closes a circuit through the release magnet 51 from ground G7 through the contact of springs' 104 and 105 and the said releasey magnet 51 tobattery B. The magnet, upon energizing, restoresthe switch shaft and sideswitch wiper to normal position and its own circuit is broken by the denergizing of theY relay A99, which is caused by the separation ofthe off-normal' springs 121 when the shaftreaches its ,lowest position. A furlther result due to the energization of the relay 99 isthe-opening of the circuit of the relayf87 at the springs 104'and 103. The relay 8,7, upondeenergizing, opens the holding circuit forthe relay 86 ,of the selector E and the. holding` winding .19 of the line switch Cif The relay. 86, upon denergiz'ing, closes a circuit through the release relayA 410'. This circuit extends from ground G4 through `thencontact of springs S3, springs 84,01%

Ves

net 37 to the batteryy lead 100. The selector E releases, breaking the circuit of its own release magnet when theshaft reachesits lowest position. The winding 19 o f the line switch C, upon becoming denergized, allows the plunger arm 15 to return to normal position It no'w having been explained how one subscriber establishes connection and `releases thesame, it will be explained 'how' a connection is prevented from being made with a busyy line and :how the calling subscriber receives a'busysignal when calling a busy number. If the number called 1s busy, thererwill be ar guarding potentialV upon the connector private bank contact, justas explained in connection with theY line switch C. The connector private wiper, upon engaging this guarding contact and at the instant the side switch passes to third position before the circuit of the private magnet 541 is broken, completes a circuitthrough the relayL 60. This circuit extends from ground on the said private. wiper 47 through the contactof springs 110 and123,

the lower winding of said relayOfand the side switch wiper 50 to battery B. The relay 60, upon energizing, closes'a locking circuit for itself extending from ground G7 through the contact of springs 1011 and 103,l

springs 93 and 94, springs 124 and 120, up-

per windingof the relay 60. and through the side switch wiper 50 (in thirdposition) to battery B. y rA further result due to the energization of the relay .60 is the giving of the busy signal to the calling subscriber. 1 This upon the hook, thereby releasing the connection in the manner above described.'

It will thus be seen that lI "have devised a very efl'icient tele hone system in Vwhich the A automatic se ector and connector switches are provided with motor magnets controlled by Vas'eries of impulses ofL one character, while the Vswitching operations of said switch are controlled by impulses impulses are 'transmitted tothe automatic switches over two sides of metallic line circonnection with certain vtypes ofautomatic switc'lie s,'it will, of course, be understood that invention is notv limited to Vswitches y sively bring said operating magnets under v eration of said second magnet. of a different character. Further-more, these intacta f of this type, but is equally as well ladapted for use in connection with other systems which require separate and distinct operations over a single circuit. Y

What I claim as my invention is :mi 1. In atelephone system, an automaticV switch having a plurality of operating magv nets, means for switching a connection from one to the othery of said operating magnets, means including an yimpulse controller and an impulse circuit over which current flows when closed for controlling said operating magnets by impulses of one character over said circuit, and for controllingsaid switch- L ing operation by impulses of a second Vcharacter kover said circuit, the resistance of the circuitwhen thus closed being the same in both operations.v

.2. In a telephone system, an automatic switch having a plurality of operative movements, and means for controlling the operation of said switch by va series of impulses of one frequency, followed by one or more rapid impulses. j j

, E. In'v a telephone system, `an automatic switch having a plurality of operating ele! ments, means for switching the connection from one to the other of saidoperating elements, means forl controlling said operating elements by impulses of one frequency, and means for controlling said switching operations by one Yor more rapid impulses.

4, In a telephone system, an'automatic switch, a trunk line extending thereto, said.l switch including a line relay anda plurality of operating magnets, means foroperating. said line relay by impulses' of one character vto control the voperation of sadswitch, and means for operating said line relay by impulses oi. a different character to succesthe control of said relay.. y Y o 5."In a telephone system, an automatic switch, a trunk line extending thereto, a line relay, a pair of operating magnets,'means for transmitting` a plurality of ,impulsesVV through said line relay to control the operaf i tion of one of'said operating magnets, and` meansl for then transmitting one or more rapid impulses through said vline relay fto bring said second operating magnet under;V the control of said line relay, said iirst means orfthen transmittingone or more impulses through said line relay to controltheop- 6.,-In a telephone system, an automatic switch including a plurality of operating magnets,`as`ide switch Vfor successively con-V trolling the circuits ofsaid magnets, means for controlling the operationorsaid mag-12H5V I nets by impulses of one character, and means Y for controllingthe operation of said side switch by one ormore rapid impulses. y l7. In'a telephone system, a line circuit,`

an automatic switch having a 'pluralityof-l operating magnets, means for switching a connection from one to theother of Vsaid operating magnets, means including an iml p ulse'controller and an impulse circuit over which 'current flows whenclosed for controllingsaid operating magnets by the impulses of one characterover saidcircuit, and for controlling ksaid switching operation by impulses of'a: second character `over said circuit, said impulses 'being transmittedoverk two sidesof said line circuit in series, theV resistance of the circuit when thus closed being the same in both operations.

8.111 a 'telephone system, a line circuit,

an automatic switch having a plurality ofV operative movements, and means forcentrolling the operation of said switch by a series of impulses of one frequency, followed vby one or more rapid impulses, said impulses being transmitted over twQsides of said line circuit in series. i

9. In a telephone system, a line circuit, an automatic switch having a plurality of operatingk elements, means for switching the connection from one to the other of said operating elements, means for controlling said operating elements by impulses of one frequency, and. means for controlling said switching operations by one or more rapid impulses, said impulses being transmitted, over two sides of said line circuit in series.

10.111 a telephone system, an automatic a switch, a 4trunk line extending thereto, said i switch including a line relay and a plurality of operating magnets, means for operating said line relay byimpulses of one vcharacter to control lthe 'operation of said switch, and meansy for operating said line relay by im'- pulses of ab different character to 'successively bring Vsaid operating magnets under the control'of said relay, said impulses be#` ing transmitted over a circuit including two sides of said trunk line in series.` j i 11. In a telephone system, an automatic switch, a trunk line extending thereto, a

line relay, a pair of operating m.agnets,

means for transmitting a pluralityo'f impulses through said line relay to control the operation of one of said operating magnets,

said magnets by impulses of one character,

and means for controlling the operation of said side switch by one or more rapid im pulses, said impulses being transmitted over two sides of said line circuit in series. i

13.111 a telephone system, `a conductor and a source of current forming a iii-cuit, a

ltelephone for said circuit, an impulse sender for said circuit, line, a telephone .for said line, an automatic switchy associated with f said circuit, a relay and propelii'ngmagnets for said switch, means including said'sendei for variably affecting the frequencyof energizations of said relay for controlling said magnets to build up a talking circuit vbetween'said circuit and said lin-e and means forfdisconnecting said relay vand for substituting another relay through which current for talking purposesis supplied to the said talking circuit. i Y

14. In a telephone system, an automatic switch having a plurality ofoperating inag-r nets means for switching a connection from one'to, the othervoffsaid ope ating magnets,

means for controlling said 'operating magnet by impulses 'of onecharaeter, means for controlling said switching operation by im-` pulses of4 a second character, and means for producing said impulses by breaking the .line circuit. f

15. In atelephoneexchange-system, the combination with an. automatic switch, means for directing the action of said switch in response to-curreut impulses ofv acertain frequency, of meansfor said switclil responsive to current impulses of a, different fre?- quency for shifting the directive means, substantially as set forth.

VlG.In a telephone system, a subscribers line, a plurality of automatic switches, an impulse transmitterat the station on rsaid line adapted to control the-variable setting of said switches by impulsesproduced in the line circuit andl to cause the change over from one of said switches to the next by an vimpulse of shorterlduration thanthe setting impulses. wv i li'. In a telephone system,a subscribers line, a plurality of automatic switches, an

impulse sender at the substation 'on Vsaid yline adapted'to produce a uniform series of interruptionstherein to control the variable setting of said switches and to cause the change over from one switch to the next` by a short interruption following each se'- ries.

18. In atelephone system, an automatic switch having a plurality of operative pinovements, and means for controlling the operation of said switch by a series of impulses of uniform duration, followed byan impulse of shorter duration. Y'

v19.v InA a telephone system, an automatic switch having 'a plurality of operating elements, means for switching the connection from one to the other ofsaid operating elements, means .for controlling` said operating elements by' impulses of a certain length, and means for controlling said switching means by an impulse of lesser length.

20. In a telephone system, an automatic switch having azplurality of operating ele-Y ments, means lor switching the connection from one to the other oit said operating elefor producingsaidv impulses by breaking4 the line circuit.

21. In a telephone system, a subscribers line, means l'or extending said line comprising an automatic switch, primary and secf ondary operating magnets V in said switch, meansI for producing successive series of iinpulses of a particular duration inthe line Vcircuit to cause the successive operation of said magnets, andv meansv for causing the change over from one magnet to the other by an impulse. ofl shorter duration than the operating impulses.

22.111 a telephone system, an automatic'.

switch having primary and secondaryV oper- Y ating magnets, a'contiol relay anda circuit therefore, meansxfor transmitting successive i series oimpulses over said circuit, whereby said magnets'may be successively.;operated.

undercontiol of said relay, means for transmitting anL impulse l of shoiter `duration sponsive to said short impulse for shifting -the control fof saidrelayf-from one magnet to the other.y Y Y 23.y In `a telephone system, subscribers lines, an automatic connector switch, means for'o'perating said switch toconnect with a dcsired called line, test andv switching relays in said :connector adapted, respectively, to

give the calling subscribera busy signal and to complete connection to a called line, means for ycompleting a-circuit through said relays in' series after the connector has operated, said test `relay being normally unresponsive thereto, and Va test Wiper conoperating with` the test contact ol the called line -tocause the Venergization of one orftheV iiected to the junction of said relays and cof other of said relays, depending onwhether prising talking conductors, means for operat-ing said `switch to connect said-conductors with a desired called line, aswitching relay in said connector controlling contacts in n said conductors, a Vtest relay, acircuitcomis established f the yjunction ol' said relays, test contacts lor said,V lines, anda busy potential onthe testKY contact o' thercalled lineif-the saine is :in

use, whereby the saidrswitching relay will be short circuited andthe said test relay will be energized by way ofsaidjtest wipeiz 25. In a i telephone system, subscribers lines, anyvautomatic connector switch, means for operating said switch to conii'ectwith a desired called line, test and switchingrelays '-gized thereafter .to close a circuitthi'ough than the*A operating impiilses,'and means re said relays in series,and atest wiper'connectcd to the, junction 'of said relays and coL operating withV thc test contact of the calledV line to cause the energization of either the-' said test relay 'or the saidswitching'relay,

depending on whether the called-lineiis busy or idle.

' Signed by me at Chicago," Cook. county,

Illinois, this 2nd dayV of April, 1914.'-

llVitnesses:

HERBERT W. KRACKE, ,y B. GARBER.

BERNARD, D; WiLLis,

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