US1664011A - Automatic telephone system - Google Patents

Description

March 27, 1928.

J. WICKS AUTOMATIC TELEPHONE SYSTEM Original Filed July 6, 1921 3 Sheets-Sheet ,1-

w Inuen or" John Imhcks March 27, 1928.

' J. WlCKS AUTOMATIC TELEPHONE SYSTEM Original Filed July 6, 1921 2 s 6 e h s s t e e h S 3 March 27, 1928.

J. WlCKS AUTOMATI C TELEPHONE SYSTEM Ori inal Filed Julv 6. 1921 s eet's --Im.ran ur- John Dhaka Patented Mar. 27, 1928.

UNITED STATES PATENT OFFICE.

JOHN WICKS, or onreaeo, ILLINOIS, assrenon 'IO AUTOMATIC ELECTRIC INC., on

CHICAGO, ILLINOIS, A CORPORATION or DELAWARE.

AUTOMATIC TELEPHONE SYSTEM.

Original application filed July 6, 1921, Serial No. 482,765. Divided and this'ap'plication filed December 7,

. 1925. Serial No. 73,553.

The present invention relates in general to automatic telephone systems, but is more particularly concerned with methods of handling long distance calls in such systems; and the general object of the invention is to provide a new and improved toll service trunking system for connecting local subscribers in automatic exchanges with long distance lines either as scribers.

A special object of the invention is the provision of a new and improved toll service trunking system containing improved circuit arrangements whereby the toll operators can connect with desired calling or called automatic lines which are equipped with p'ayStat-ions, and whereby such operators can thereafter collect or refund depos-.

ited coins as the occasion requires.

This application is a division of Patent #1,633,149 issued to me on June 21, 1927. Those features ofthe invention which-relate generally to the toll service trunking system are claimed herein, while the paystation features are claimed in the prior application referred to. r I

Referring to the drawings, comprising Figs. 1, 2 and 3, there is shown by means of the usual c rcuit diagrams the apparatus required to establish a complete connection from a toll lineterminating in the jack J, Fig. 1, to a local subscribers station A, Fig.

3. This apparatus comprises the cord circuit 0, Fig. 1, located at the toll operators position in a toll switching station or ofiice;

- the two conductor trunk line extending from jack J in the toll switching ofiice through the relay group D, which is a form of repeater associated with the jack J and its multiples and which is used. for translating ground impulses sent by the operators callin device to ordinar 7 two wire im ulses to the transmission repeater E, Fig. '2, in a.

main exchange of the system; the toll first selector F, Fig. 2; and the toll rotary connector H, Fig. 3. The repeater, first selector and connector mentioned are allin the same office or exchange, which as indicated above may be one ofthe main oflices or exchanges of a large multi-ofi'ice system.

Fig. 4 shows certain connections of the test contacts in a certain level of the connec tori-i which are necessary in order to enable calling or called sub-' H will be operated into connection with the first set of contacts. Should thefirstline be busy. the connector will be automatically .operated until connection is made with an idle line in the group. If all the lines'in the group are busy the connector will not operate but will maintain itself associated with the first set of bank contacts, transmitting a busysignal to the calling party, and as soon as one of the grounded lines become idle the connector will then operate to selectit.

As has been pointed out hereinbefore, a

feature of the invention is the provision of suitable arrangements whereby thetoll operatorcan collect or refund coins deposited to pay for a toll connection, and it shouldbe explained that the subscribers"stations, or some of them. at least, are provided with coin collecting devices, or paystations, of'the well known type which is described in the U. S. Patent to Forsberg, No. 1,043,219. Paystation equipment of this type is shown diagrammatically in connection with the substation A, Fig. 3.

In so far as the measured service features of the present 'case is concerned it may be considered as an improvement on the system shown in Patents No. 1,616,402 and No. 1,586,057, issued to me on February '1, 1927, andMay 25, 1926, respectively. In respect to certain other features of the toll service trunking system the present system is closely related to the system disclosed in Patent No.

1,604,372, issued on October 26, 1926. In

y W desired distant exchange over one of her toll.

lines, such for example asjthe toll line which terminatesi'nthejaclrl'hig. 1, and having "ordered'the'- proper local line to be connected 'up" in that'exchange, the toll operator Will neXtp1-oeeed to call the subscriber at sub- 's't'ati'on A by 'ingfl-s'ystem. Observing that the toll trunk iby'fthenormalposition of the visual 30, the 4" operat'or will insert the calling plug 1?" of "the cord'circ'uit into the'jack'J, the call fing deV'ice key K being thrown shortly 7 after. "Upon'the insertion of thieplug P" intothe jack J",'a circuit is completed which exterids'fronrground, by way of the springs "29 'of'the keyK, sleeve of the plug 'P, "sleeve'of the jack J, through the resistance 75, and thence through the winding of the- 1i'ne1relay42 of the repeater D to battery. """The'li.'ne'relay 42 is energized overthis circuit and, 1 upon operating, completes the cir-' cuit of the slow acting relay 45. Relay 45, "upon energizing, prepares a circuit for relay in the repeater D 'atarmature 66, and at armature 65 completes the circuit of the visuals such as 30 and 31-before the various toll operators in order to inform them that the *ztssociated toll trunk is now in use.

' WVhen'the line relay 42 energizes, abridge W is completed across the trunk conductors 70 "which energizes'the line relay'151 of the selector F, Fig.2 over' a circuit which may be traced'asfollowsz'From battery through the upper winding of the line relay 151, "armature 17 3and'its backcontact, normally cl''osed'fsprings controlled by armature 117,

normally closed springs controlled by armature 122, upper'left'hand winding of the 'i repeating'coil R, conductor 70, normally closed springs controlled by armature 54, winding of the polarized relay 44, armature 53 and its'front contact, trunk conductor 71, flower left hand winding'of the repeating c'oil R, and thence through the normally closed springs controlledby armature 123 to" ground. Theline relay 151 of the toll first selector F, Fig. 2, is energizedover this circuit and, upon operating, completes the circuit of the 'slow' acting' relay 152. Relay 152', upon energizing, prepares the impulsing circuits 'of'the first selector F in the usual" manner. VVh'en thefcalling device key *K is operated the impulse springs of the calling device S are included in the above way of the toll 'service'trunl-:-'

traced circuit of the line relay 42 of the repeater D. v

The toll operator will now operate her calling device S in accordance with the telephonenum'ber'of-the subscriber 'a't substation A. When theral'ling device dial is operated in accordance with the first digit of thenuinber, a series of interruptions is produced'in the circuit of the dine relay 42 of the repeater D. The line relay 42jdeenergizes a plurality of times in response to these interruptions, each time opening the previously traced bridge across the trunk conductors and 71 at its armature 53. Tn this nianner the-first series of. impulses are repeated to the line rela'y 151 of the toll first selector F. At each retraction of; the terminating in jack J is idle, as indi'cated' armature 52 of the line relay'42, an impulse of current is sent to the slow acting relay 40. Upon energizing, relay 4O provides v a bridge across the trnnkconductors 70 and 71 at its armature 51*whi'ch does 'not include the windingiof the polarized relay 44, and at itsarmature 50 places a direct bridge across 'the abox' ementioned trunk conductors on the left ha'nd'side of the condensers soas to prevent the discharge from the condensers,

due toldialing, being heard by the toll oper- "ator. 'By' the removal of the polarized relay 44 fromin bridge of'the trunk conductors the'in'ipulsingcircuit of the line relay 151 of'the first selector F is greatly improved.

In the first selector F the circuit of the line relay 151 being opened a. plurality of times by the operati'on of the relay 42 the repeater Dthe former relay will retract its armature 166 a corresponding number of times, each time sending an impulse-ofcurrent to the vertical magnet 1'15 of the selector F in series with the slow acting :re and 71 of the outgoing-toll serv1ce.trunk" lay 153. Magnet 175 operates to raise the switch wipers 183486,inclusive. step by step untilthey are placed opposite the level of bank contacts in which are terminated trunk lines leading to the desired group of' connector switches: Upon the first off normalstep-of the first selector F the off normal springs are shifted and a circuit is completed which extends from ground, way ofoff normal s rin 171 and its workin contact through resistance 138, and thence through the polarizing winding of the electropola-rized relay 103 to battery. Theelectrowinding. The slow acting relay 153is energiz'e'd in series with the vertical magnet, and

upon the first vertical step of the switch shaft, completes a circuit which extends from ground on release trunk conductor 17 6,

by way of front contact and armature 168, oftnormal spring 170 and its'workingcontact, and through the winding of the stepping relay 154 to battery. Relay 154, upon energizing,'establishes a locking circuit for itself at its armature 169, and at armature 170 prepares a circuit for the rotary magnet 180. Shortly after the termination of the vertical movement of the switch, the slow acting relay 153 deenergizes and the circuit of the'rotary magnet is completed,'this extending from ground on release trunk conductor 176, by way of normally closed springs controlled by armature 168, armature 170 and its front contact, and thence through the winding of the rotary magnet 180 to battery. Magnet 180 operates to rotate the switch wipers 183- 86, inclusive, into engagement with the first set of bank contacts in the selected level and at the same time opens the locking circuit of the stepping relay 154, which deenergizcs, opening the circuit of the rotary magnet, which deenergizes also. i

Assuming-that the trunk line, with which the switch wipers are now in engagement, is busy, there will be a ground potential present upon the test contact engaged by the test wiper 185, and a circuit will be completed which extends from the said grounded test contact by way of test wiper 185, armature .162 and its back contact, back contact and armature 179, off normal spring 170 and its working contact, and through the winding of the stepping relay 154 to battery. Relay 154, upon energizing, establishes a locking circuit for itself and completes the circuit of the rotary magnet. The rotary magnet operates to rotate the switch wipers into engagement withthe bank contact associated with the next trunk line in the selected level and at the sametime opens the locking circuit of the stepping relay 154, which deenergizes, opening the circuit of the rotary magnet, which deenergizes also. The alternate operation of the stepping relay 154 and the rotary magnet .180 will continue until an idle trunk is found, which, we will assume, is the trunk line terminating in the bank contacts 187190, inclusive. WVhen the switch wipers are rotated into engagement with this trunk line, there will be no ground potential present upon the test contact-189 engaged by the test wiper 185 andno circuit will be completed for the stepping relay 154.

As theswitching relay 150 is no longer short.

circuited, the said relay will be energized over a circuit which may be traced from ground on release trunk conductor 176, through the winding of relay 150, back contact and armature 179, off normal spring 170 and its working contact, and thence through the winding of the stepping relay 154 to battery. It may be mentioned at this point that the relay 150 is of sufliciently high resistance to prevent the energization of the stepping relay 154 in series with it.v Relay 150, upon energizing, completes the energizing circuit peating coil R, upper winding of the electropolarized relay 103, back contact and arma ture 121, upper right hand winding of the repeating coil R, normally closed springs controlled by armature 111, back contact and armature 130, armature 160 and its front I contact, front cont-act and -,armature16 5,

wiper 183, back contact 187, trunk conductor 191, normally closed springs controlled b armature 235', armature 215 and its bac contact, through resistance 220, and thence through the upper winding of'the line relay 201 to battery. The electropolarized relay 103 in the repeater E is not energized at this time as the current flowing in its upper winding is not in the proper direction. The

line relay 201 of the connector switch H is energized over this circuit, and, upon operating, completes the circuit of the slow acting relay 202. Relay 202, upon energizing, prepares the operating circuits of the connector H at armature 225 and at armature 224 completes a circuit .for the ring cut off relay 208. Relay 208, upon energizing,

establishes a locking circuit for itself at armature 256,*which may be traced from ground at the transmission repeater E, by

way of armature 111 and its back contact, armature 161 and its front contact, wiper 184, bank contact 188, trunk conductor 192, armature 256 and its front contact, and

thence through thewinding of the ring out off relay to battery. Anotherresult of the energization of relay 208 is that the ringing circuit. which would normally be operative immediately upon the connector H connecting with the called line, is opened, and, by

means ofthe previously'traced locking circuit, placed under the control of the toll operator. It will be noted that the trunk conductor 193 is the release trunk conductor and that it has ground placed upon it from the slow acting release relay 152 of the toll first selector F. It will. also'be noted that the switching relay 150 of the selector F, upon energizing, did not open the circuit of the line relay 151 and therefore this relay remains under the control of the. line relay 42 of the repeater D. It will be remembered that the previously traced circuit of the line relay 201 of the connector H includes the armature 165 of the'line relay 151. Y

It will .now be apparent how the connector H is controlled. When the toll operator operates her calling device in accordance with the-next digit of the subscribers number atsubstation A, a series of interruptions isproduced in the circuit of the line relay 42- and the repeater D and these are in turn repeated to, theiline relay 151 of the first selectorvF. Ateach retraction of its armature 165, the circuit of the line relay 201 is opened and. the impulses are thus sent to the line relay 201 ,of, the connector H in. order :tocontrolits operation. At each retraction of the armature 221 ofthe line relay 201,-. a circuit is completed which extends from ground, by way of back contact and armature 217, armature 221 and its back contact, armature 225 and its front contact, 01f normal springs 228 and 227, through the .winding of,the vertical magnet262, and

thencethroughthe Winding of the slow acting-relay 207, to battery. The above is the circuit" over which the first impulse to the 'vertiealcmagnet is transmitted. Upon the first vertical stepofztheswitch, the oif normalsprings are shifted and the remaining venticalmagnet impulses traverse a different circuit, which is the same as the one previously traced, except that it includes the tains its armature attracted throughout the vertical movement of the switch and at the termination thereof deenergizes and prepares the impulsing circuit ofthe rotary magnet 260.

The toll ,operator may 110w operate her callingdevice in accordance with the next and final digit of the called subscribers number. As before, the line relay 42 of the repeater D and the line relay 151 of the selector F, operate and transmit series of impulses corresponding to the last digit of the .called numberto the line relay 201 of the connector H. Relay 201 deenergizes a plurality of times in response to these interruptionseaeh time sending an impulse of current over the following circuit: Ground. by way of backv contact and armature 217, armature 221 and its back contact, armature 225 and its front contact, off normal springs 228 and 229, armature 253 and its back contact, back contact and armature247, through the winding of the slow acting relay 206, armature 242 and its back cont-act, and thence through the winding of the-rotary magnet 260 to :battery. The rotary magnet operates to rotate the switch wipers 270- 273, inclusive, into engagement with the set will-be completed for the test relay Then, following the deenergization of the slow acting'relay 206,, a circuit may be traced extending from ground, by way of front contact and armature 223, back contact and are mature 245, lower winding of the switching relay 203, back contact and armature251, test wiper 271, test contact 275, winding of the switching relay 280 of the line switchand thence through the winding of the motor magnet 282 to battery. Relays 203 and 1280 are energized over this circuit. However, due to a mechanical interlocking device con trolled by the armature of the line relay 281, which is now normal, the switching relay 280 only partially attracts its armatures, that is, enough to disconnect the line of the called substation, A from its normal battery and ground connections in the line switch C. Relay 203, upon energizing, locks itselfto ground on release trunk conductor 19.3 at

armature 237, prepares the circuit of the rev lav 200 at armature 238,]and at armatures 235 and 239 r es t c nne tion f the line rely 201 with regard to the trunlg eonductors 191 and 194. the current flow is now reversed in the upper winding of the electropolarized relay 103 in the, transmis- .7

sion repeater E which is included in the'circuit of the line relay 201, this relay will be operated. Relay 103, upon energizing, establishes a locking circuit for itself at armature 120, atarmatures 122 and 123 reverses connections of the line relay 151 of the first selector F with regard to thetrunk conductors 70 and 71, and also at armature 122 ,connects the alternating current relay 104 across the trunk conductors 70 and 71. The normal current flow over the conductors 7.0 and71 being now reversed, the polarized relay in the repeater D is energized. Belay 44,1ipon operating, completes the circuit of the relay 43. Relay 43, upon operating, establishes a locking circuit for itself at armature 56, atarmature 55 places an additional ground upon the conductor which extends, to the visuals and 31.and at armatures 5'4 and V 58 short circuits the condensers which are normally included in the trunk conductors and 71, atv the same time removesthe polarized relay 44 from in bridge across these conductors. The condensers in the trunk conductors 70 and 71 having been short circuited by the operation of the relay 43 in the repeater D, the relay 14 in the bridge of the cord circuit O is energized in series with the line relay 151 of the toll first selector F. Relay 14, upon energizing, completes a circuit for the supervisory lamp L at its armature 25. By the operation of'this signal, the toll operator is notified that connection has been established with the desired line. l

Returning now to the operation of the electropolarized relay 103 in the repeater E, another result of its energization is that the circuit ofthe line relay 201 of the connector H is opened at armature 121 and at the front contact of this armature and the front contact of armature 124 the battery feedtrelay 102 is connected to the conductors 191 and 194 inorder to supply talking battery to the called subscriber when he answers. It will be seen that ground through the upper Winding of relay 102 stands against ground through the line relay 201 and the battery through the lower winding of relay 102 stands against battery through the line relay 201 hence relay 201 will deenergize. The line relay 201, upon deenergizing, completes the circuit of the relay 1200. Relay 200, upon energizing, disconnects the line relay 201 from the trunk conductors 191 and 194 at armatures 215 and 219 thereby providing a direct metallic circuit to the called line from the repeating coil R in the repeater E, and at armature 216 opens the original energizing circuit of the ring cut off relay 208.

The next operation is to ring the subscriber at substation A. For this purpose the toll operator momentarily operates her ringing key K thereby projecting ringing current out on the trunk line comprising conductors 7 0 and 71 which operates the alternating current relay 104 in the repeater E over a circuit extending from the free pole of the generator G by way of normally closed springs of key K normally closed springs of key K working contact and spring, 27 of key K ring of the plug vP, ring of the jack J, armature 54 and its front contact, conductor 7 0, upper left hand winding of repeating coil R, front contact and arma ture 122. At this point the circuit divides, one path extending through the winding of the alternating current relay 104 to the left hand winding of the repeating coil R,trunk conductor 71, front contact and armature 58, tip of the jack J, tip of the plug P, spring 28 of key K and its working contact to ground. A second path extends'through the high resistance relay 100 to ground by way of armature 116 and its back contact, and the third path extends by way of armature 131 and its back contact, through the resistance 139, armature 115 and its back contact, through the lower winding of the line relay 151 of the first selector F to ground.

conductor The relay 100 is of very high resistance and will not be operated bythis-ringing current. The alternating current flowing through the lower winding of the line relay 151 of the first selector F has no effect on it asfa circuit for its upper winding is completed from ground at the working] contact of spring 28 of key K in the cord circuit, 0. The alternating current relay 104 is operated over the previously .traced ringing circuit, and, upon attracting its armature 129, completesthe circuit of the relay 101. Relay 101, upon energizing, removes ground from the ringing control conductor 192 at armature 111. This operation opensthe locking circuit of the-ring cut off relay 208 in the connector H. The latter relay, upon deenergizing, completes the ringing circuit of the called subscriber. The subscriber at substation A will now be intermittently signalled until he responds. When thereceiver is removed at the called substation the ring out off relay 208 is energized over the called subscribers line loop an'd,'upon operating, reestablishes its former locking circuit to ground on the ringing controlconductor 192, the operator having restored her ringing key by this time to permit the deenergization of the relay 101. Relay 208',

upon operating, locks itself energized atarmature 256, and at armatures255 and 257 opens the ringing circuit and at the'front contacts of these armatures' finally com.- pletes the talking connection. Talking. battery is now supplied to the transmitter at substationA from the windings of the battery feed relay102 in the repeater E. This circuit will not be traced in detail but it will be observed that the lower line extends uninterruptedly back through the connector H and the selector F to the lower right hand winding of there'- peat-ing coil R from whenceflit extends through the lower windingof the battery .feed relay'102 to battery, while the upper line conductor 191 extends back through the connector H and the selector F to the upper right hand winding of the repeating coil R from which point it may be traced through the said winding and through the upper winding of therelay 102 to. ground. Relay 102 is energized by the current flow over the called line loop, and, upon attracting its 'armature'114, places an additional ground upon the ringing control conductor 192. Another result of the energization of relay 102 is that the high resistance relay is placed in bridge of the trunk conductors 70 and 71. This bridge may be traced from trunk conductor 70, upper left hand winding of the repeating coil R, front contact and armature 122, winding of the high resistance relay 100, armature 116 and its front contact, resistance 125, armature 123 and its front contact, lower left hand. windof therepeating coilR to trunk conductor ' of relay 102 is that the line relay 151 is disconnected from the trunk conductors 7 0 and 71 and a local circuit is completed for it, which extends from ground through the lower winding of relay 151, resistance 136, armature 117 and its front contact, back contact and armature 173, and thence through the upper winding of the line relay 151 to battery. The line relay 151 having been disconnected from the trunk conductors 7 O and 71 no battery will be present thereon and there-will be no circuit for the relay let in the operators cord circuit for which relay will deenergizeto 'eiface the supervisory mp I a The operator willnow come in on the line by throwing the listening key K? and,

after. observing that the proper person is at the telephone,- will request the called party to deposit the coinor coins to pay for his connection. llVhen the coins are deposited,

; the operator is given an audible signal over the telephone circu1t in the usual manner so that she will know that the correct amount has been deposited, :and also the polarized magnet of the paystation apparatus is con- ,nected to the line in order that the operator may thereafter either collect or refund the depositedcoins. I

Everything is now in readiness for the conversation to begin, at least so far as connection to the subscriber at substation A is concerned. Assuming that the desired party has been obtained in the distant exchange the operatorwill nowcomplete the connection at her cord circuit and the connected parties can converse as desired. Itwill be observed that the connection I includes the two. conductor trunk. line from the toll switching station to the main or local ere,

change (the trunk comprising conductors and 7 1) which is a decided economy over former arrangements which sometimes require three or four conductor trunk lines. Another advantage which may be pointed p out is in the arrangement by which the station A called subscriber controls the release of the connection while his receiver is off through the medium of the relay 102 which controlsthe local circuit of the line relay 151 of the first selector F. This arrangement makes it possible for the toll operator to change cord circuits after the called party has answered without releasing the established connection.

When the conversation is terminated both subscribers will replace their receivers. Upon the replacement of the receiver at subthe relay 102 in the repeater E is deenergized and theoline relay 151 is again connected to the trunk conductors 70 and 71. As a result, the supervisory relayl l in the operators cord circuit is energized and the supervisory lamp L is lighted to give the operator a disconnect signal. Before releasing the connection the operator will have to collect whatever coins were decommon to all the cord circuits at the oper- 1 ators position and, when thrown, serve to connect either ofthe high voltage batteries B or B to the generator leads extending to the various ringing keys in the cord circuits. By the operation of the ringingkey K the high voltage battery B is connected to the trunk conductor 70 from whence it flows through the upper left hand" winding of the repeating coil R, front. contact and armature 122, through the winding of the high resistance relay to ground by way of armature 116 and its back contact. The relay 100 is operated by the high voltage current from the battery B, and, upon energizing, closes the circuit of the slow acting relay at its armature 110. Relay-105, upon energizing, completesa localcircuit for the upper winding of the line relay 15.1 at armature 133 so as to maintain the selector F and connector H in their operated positions, connects the trunk conductor 7 0 direct to the trunk conductors 191 and 194k by way of the armatures 131, 130, and 13 1, over the talking conductors and wipers of the selector F and at the same time connects the conductors 191 and 194 to ground by means of the resistance 1 10 and the condenser at armature 132. Current now flows from the battery B, through the low resistance relay 32, springs of key Kiworking contact of spring 27 and the said spring, ring of plug P,ring of jack J, conductor 70, frontcontact and armature 131, front contact and armature, 1'30, armature 160 and its front contact, front contact and armature 165, wiper 183, bank contact 187, conductor 191, front contact and-armature 257, armature 239 and its front contact, armature 219' and its front] contact, wiper '273, bank contact 277 and. thence through the polarized magnet at the subscribers substation to groundi The current from the battery B flows in the circuit of the polarized magnet inthe proper direction to operate it to collect the deposited coinor coins, the paystation mechanism being reset at the same time.

lVhen the circuit through the polarized magnet is established the resulting current flow is sufiicient to operate the relay 32in series with the matter lead from the battery B and this relay, upon operating, closes the circuit of the supervisory lamp L thereby collected. The supervisory lamp L is common to all the cord circuits at the position and notifies the operator of the successful collection or refunding of coins.

While it is true that the alternating current relay 104 will energize momentarily due to the charging of the condenser 159 the momentary operation of the armature 129 will have no efiect as the relay 105 operates at once andground is removed from the armature 129.

' In order to assure herself that the coins have been collected at the subscribers substation apparatus the toll operator will operate the key K twice. If everything is functioning properly the coins at the substation will be collected upon the first operation of the key K and, upon the restoration of the key to normal, the polarized magnet at the substation will be disconnected from the line. When the key K is again operated there will be no circuit for the relay 32 and consequently the lamp L will not be lit. As this signal does not operate the toll operator will know that the coins deposited have been collected and she will restore her ringing key to normal and also the master collect control key K If the toll operator desires to refund the deposited coin rather than collect it she may do so by operating the master refund key K and then her ringing key K Assuming that the same connection exists as in the previous case where the operator collected the coins, if the master refund key K is operated the battery lead from the battery B is connected to the conductor 70. This is a high voltage battery the same as the battery B but it supplies current of the opposite polarity and it follows therefore that the polarized magnet at the substation A will be operated in the opposite direction to refund the deposited coins rather than collect them. Except as pointed out the refunding operation is the same as the collecting operation and the operator is given supervision by means of the lamp L in the same manner as was before described.

Under certain conditions the toll operator may find it desirable to collect or refund de posited coins at substation A before she connects the two parties together for conversation. She may desire to refund'the deposited coins in order to assure herself by a repetition of the usual audible signal when the coins are placed in the coin box that the proper'amount has been deposited. This operation will now be briefly described. The receiver at substation A being off the switchhook the battery feed relay 102 in the repeater E will be energized and the high resistance relay 100will be placed in bridge of the trunk conductors and 71. Now when the toll operator goes through the regular operation of refunding by operating the two trunk conductors 70 and 71 in series.

As a result of the operation of relayflOO a circuit is completed for the slow acting relay 105 and the refundingoperation from this point on takes place in thesame manner as was before described.

The release of the main connection over the toll service trunk is brought about by the removal of the plug P from the jack J at least this is true if the called subscriber has replaced his receiver. In order to explain this more fully it Will be assumed that the plugis removed from the jack J before the subscriber A has hung up. By the removal of the plug P, the circuit of the line relay 42 ofthe repeater D is opened and this relay will deenergize but the relay '43 remains locked up. The busy Visuals 30 and 31are thusmaintained operated to indicate that. the trunk is busy. Now, when the called. subscriber replaces his receiver, therelay 102 in the repeater E is deenergized and the line relay 151 of the toll selector F is connected across the incoming trunk conductors V 70 and 71, as was explained hereinbefore in connection with the control of the supervision. The effect of this is to energize the slow acting relay 41 which was placedin a bridge across the trunk conductors 70 and 71 by the deenergization of the slow acting relay 45, the latter relay having deenergized shortly after thedeenergization of the line relay 42. Relay 41, upon energizing, opens the locking circuitof the relay 43. Relay 43,

upon deenergizing opens'the circuit through the visual 30 and 31 thus rendering the trunk line idle and also disconnects the slow acting relay 41 from in bridge of the trunk. 'Re 7 lays 41 and 151 are thereby deenergized. The latter relay breaks the circuit'of the slow acting relay 152 and also breaks the operating circuit extending to the connector H. The slow actingrelay 152, upondeenergizing, completes the release magnet circuit of the selector F at armature 167 and atarmature 178 removes ground from the release trunk conductor 192 thereby allow- 1 ing the relay 203 in the connector H to deenergize. Relay 155 is energized in multiple with the release magnet 181and is therefore operated during the restoration of the switch. Relay 155 opens a point in the circuit of the upper winding of the line relay 151 at armature 173, and at. armature 174 opens a point in the locking circuit of the relay 154 so as to prevent the relay 154 energizing and looking shouldthe test wiper'185 encounter any grounded test contacts during the release of the switch. At the connector H, relay 203' upon deenergizing, opens the circuit of the relay 200. The latter relay, upon retracting 'its armature 2-17 closes the circuit of the retures attractedafter having been operated by the reversal of battery from the connector H, is openedat the oil normal springs 171 of the selector F. In this manner all the apparatus-used in'the connection is restored to I normal.

-Return-in g now to the operation of the connector H when engagement was made with the bank contacts associated with the line of the substation A it will now be assumed that-this line was busy. Under these conditions, there will be a ground potential presentupon the test contact 275 engaged by the test wiper 271. A circuit will thereby be completed for the test relay 205. Relay 205,

upon energizing, prepares a lockingcircuit for ltself at armature 246 to ground on the said-test contact which is effective immediately' following the deenergization of the slowacting relay 206, and at armature 248 places the busy tone from thebusy-machine on the upper heavy talking conductor 191.

Having called the digits corresponding to the called subscribers number the toll operatorwill restore her key K to normal. As the supervisory lamp L .is not lighted at this time the toll operator will operate her listening key K in order to ascertain whether or not the desired line is busy. The busy tone which was placed upon the upper heavy talking conductor is now audible to the toll operator and she will restore her listening key to normal and busy herself with other connections while waiting for the desired line to become idle.

I When the line of the substation Abecomes idle, ground will be removed from the test contact 275-and the test relay 205 will be 'deenerg-izedto remove the tone from the up-,

per heavy talking conductor and at the same time complete the circuit of the switching relay203.' Relay 208 will be energized as before described and will operate to reverse the battery over the incoming trunk line. By this'oper ation the-electropolarized relay 103 inthe repeater E is energized and operate-sin the usualmanner to establish a locking circuit for itself and prepare a circuit of the battery feed relay 102. Another result of the energization of relay 103 is that the battery is reversed over the conductors and 71 inthe usual manner and the polarized 'relay in the repeater D operatedto short circuit the condensers normally included in these trunk conductors. By this'operation the bridged supervisory relay 14 in the operating cord circuit is energized to light the supervisory'lamp L, thusinotifying the toll operator that the desired line has become idle. In the connector H the relay 200 is energized and a metallic circuit provided back to the repeating'coil R; The operator at the toll board notlng the operation of the lamp L will now operate her ringing key and the called line will be signaledas before described. When the called party responds the battery feel relay 102 will be energized over the called line loop andoperate to disconnect the line relay 151 from the trunk conductors 70 and 71. p This latter operation,

cause-s the supervisory lamp L in thefoper-v ators cord circuit to be extinguished and she will be notified that theconnection is completed. The subsequent operations inwhich in the manner shown in Fig. 4. F ig-.'4- represents a level of bank contacts-havingprivate lines and grouped lines, the lines of the group being fourth, fifth, sixth, and seventh bank contacts. These lines are all listed under one number in the directory and when connection is desired with one'of these lines the connectorH is rotated into engagement with the first line of the group. busy and if there is-an idle-line in the group the connector H will operate to automatically select it. However, if all lines in the group are busy the connector will remain with its wipers in engagement with *the fourth set of bank contacts transmitting a busy signal to the calling subscriber until one of the lines becomes idle. WVhen this occurs the connector will then voperate as Ifthi-s is previously mentioned. This operation of the Y connector H will now be described. For this purpose it will be assumed that the line of the substation A is the first'one of the group of lines and isbu-sy when the connector H is rotated into engagement with the bank contacts 274-277, inclusive. "As there is a ground potential present upon the test contact 275, the test relay-205 will be energized. As* the test contacts 275 "and 276 will be connected together there will also be a ground potential placed upon the test ;contact 276. Then, following the deen'ergization of the slow acting relay-206 a-circuit may be traced extending from the said grounded test contact by way oftest wiper 272, armature 250 and its back contact, armature 265 and its back contact, armature 249 andits front contact, through the winding'of the stepping relay 204 and thence through the winding of the slow acting re lay 207 to battery. Relay 204, upon energizing, establishes a locking circuit for itself at armature 240' and at armature 241 completes a circuit for the rotary magnet 260. Rotary magnet 260 operates torotate the switch wipers 270273-, inclusive, into engagement with the next set of bank contacts and also to open the locking circuit of the stepping relay 204 which deenergizes opening the circuit of the rotary magnet which deenergizes also. If this next line is busy the test relay 205.will beflmaintained energized and the stepping relay-willopen ate, as before described, to complete the circuit of the rotary magnet and-the switch wipers will be rotated into engagement with V the next set of bank contacts.

'When the switch wipers 270273,Iare rotated into engagement with a set of bank contacts which are idle there will be no circuit for the test relay 205. Then, following the deenergization of the slow acting relay 205, the switching relay 203 will be energized and the-same operations that havecbeen described before will ensue.

The relays 300303, inclusive, are associated with the test contacts of the various lines of the group and are in multiple with the private normal conductors extending. from each test" contact. Therefore, as each line becomes busy the associated relay will be energized and, when all the trunks of a group become busy the connectionbetween the test contacts associated with the first line of the group will be opened and should the switch I wipers of the connector H be rotated into engagement with the first set of bank contacts of a group of lines under these condition'sthe connectorwould operate in the same manneras if engagement were made with a private line. As soon as one of the lines of a group becomes idle. the associated relay such as relay 301 would deenergize and complete the connection of the two test contacts 275 and 27 6. The connector would then rotate into engagement with the idle line, all the foregoing operations taking place in the usual manner. Itis the usual practice in automatic telephon'esystems to take the trunk lines which extend to the private branch exchanges from the bank contacts accessible to rotary'con nector switches. The toll connector- H has access to certain of these trunk lines and should the toll operator desire to connect with asubscriberin a private branch ex change she will operatefhercalling device in to the operations of the calling device" the connection would be set up in thesame manner'as' was described hereinbefore and it will be assumed that the switches .D, E, F and H are the ones selected foruse in extending the connection to the t ejsire'd private branch exchange trunk line. When the connector -H is operated into engagement with the first trunk line going to the branch exchange, if this trunk is busy the connector will automatically operate to select an idle one of the group of. trunk lines. Upon being rotated into engagement ,with an idle trunk the switching relay 203 will be energized and will operate to reverse the battery back over the trunk line'comprising conductors 19,1 and 194 and the electro-polarized relay 103 in the toll transmissionrepeater E will be operated. Relay 103, upon operating, reverses the battery over theitoll service trunk whereby the polarized relay 44 in the repeater D is operated, as is the supervisory control relay "14 in the operators cord circuit; Relay: 14, energizes to light the supervisory lamp L thereby notifying the toll op.-

erator that the connection hasbeencompleted. The" above operations take place in the sameman'ner as was before described;

however, the trunk lines going to the branch exchange are] usually: provided :with .a'

bridged signal across the'trunk. This being the case, the battery feed relay 102 in the repeater E will be immediately energized :over theconnected trunk line, and, vupon opcrating, will complet'ea-local circuitfor the line relay 151 of the toll first selector F and place an additional groundon the: ringing control conductor 192. In addition, by the operation of relay. 102 battery is removed from the toll service trunk comprising conductors 7 Oand v7 1 and the bridged supervisory relay 14 in the operators cord circuit is deenergized tofl'extingui'sh the supervisory I 'la'mp- L.. Ordinarilythe efiacement ofzthis lamp serves to notify the operator that the called subscriber has answered. M However, the operator will remember that she has "called a private branch exchange and she vwill thenioperat e the ringing key K in the windings of the repeating coil R ,are :dis-

connected from thetrunk conductors extending to the connector at armatures 111 and 112 and the battery feed relay-102 Would deenergize wereit not for the fact that thereisa localflcircuit' completedfor it which extends from ground by way of front contact andarmature 114, through resistance 187, frohtcontact and armature: 113.- through the lower right hand Winding of the repeating" coil R, armature 124'a'nd its frontcontact, and thencetln-ough the'lower winding of the relay 102 to battery. As therelays 101 and 102 are now both energized ringing current from the generator G is connected to the trunk line extending to the private branchexchangein order to V operate the bridged ring down signal thereat. The subsequentoperations wherein theconnection is completed to the/desired called subscriber in the private branch'exehange, the conversationcompleted, and'the connection released willtake'place in'tlie usual manner-and need not be described herein;

' Having fully described and ascertained the features of the invention what; is con; sidered to be new aml desiredto have protected by Letters Patentwill be pointed out in theappended-claims.

I claim: 7 i V 1. In a telephone'system, a series ofautomat-i0 switches and interconnecting trunk lines for-'- extending'a talking connection to; a called line, one of said switches being a final connector switch, a controllingrline relay in said'connector in bridge of the associated trunk line, means for automatically reversing the line conductors of said trunk line i when the connection to 'the called 1 line iscom'plete'd, and means responsive" to said reversal for disconnecting said line relay.

2. In a telephone system, a series otautomatic switches and interconnecting; trunk lines for extending-a talking connectiorrtio a called line, one ot said switches bein-ga fin-al connector switch a controlling line re lay in said connector in bridge of. thevassoelated trunk l1ne, means for" automatically reversingtl'i'eline conductors :of said trunk line when the connection to the called line is completed, a battery feed relay in another of'said switches, means responsive to said reversal for connecting said. battery feed relay across/the extended; talking circuit,- andmeans responsive to the connecting up of said battery teed relay Yfor disconnectin'g said line relay.

3 In a telephone system, a seriesiot automatic switches and" interconnecting trunk lines for extending a talking connection-to a called line, one of said switchesbeingra' final connector switch, a controlling line'relay insaid connector in bridge of the associated trunk line, means for automatically reversing the line conductors. of saidtrunk line when the connection tov the called line is completed, a bat teryteed relay in another of said switches,-' means responsive to said reversal for connecting said battery feed relay across the extended: talking. circuit: in-

opp'osition'to' said line relay, thereby causing-saidliner'elay to deenergize, and an-' other relay responsive to the deenergizat-ion of said line relay for disconnecting said line relay.

1", In a teleph'one system, a" series. of? auto,- matic switches and interconnecting trunk lines for extending a talking i connection :to acalled" line, one 01 said! switches being a final connector switch, a controlling :line "relay insa'id connector inbridge of th'eqassocia-ted trunk line, means for automatically reversing the line conductors of said trunk line when: the connection to the called; line is completed, means responsive to said reversal for disconnecting said. linerelay, and means in another; ofsaid switches for preventing the release 03% said: connector valter said line relayhasbeen" disconnected:

5'; In a tOll" service. trunking. system, meansz'for extending-a connection from a toll operatoris switchboard to. a 'subscrihers line,saidi connecti'oncomprising three inductively connected: sections, means for re 7 'versin-g'thecurrentifibw' in the last section when the connections is: completed to the called line, means responsive to said reversal for: reversing the current inwthe intermedi ate section and means responsiveto-the second! reversal for condiictively connectingthe first-section and the interm'ediate v section together. 1

6. In a; toll-L service-trunking: system, means for; extending: connection vfrom-a toll-1 opera-tors. switchboard. to: a subscribers line, sail connection comprising three inductively connected sections, imeainsfor reversing the current fl ow 1 in" the last, section when. the connection is." completed to the called line, means: responsive toEsaid; reversal for reversing the-v cu rre'nt in the intermediate section, means responsive to thev second reversal i01 coii'cluctively connecting 1 the first section and .theintermediate section; to-

gether, a-si nalat the SWltChbOZIP-drOPQIZfllZ-Bd by current; how over thet-wo united sections, and means operated'i when the called" -subscriber answers: for stopping-- the: current flows. over, the: said :unrted' sections to etface saidsign al v 7 Ina telephone system, a main exchange and a branch exchange, a trunk. line connecting. said exchanges and, terminating in a repeaterr 'in the branch exchange, meansin cludingsaid; trunk: line 'anda connector switch int-he branch exchange fo1';co11nectinga calling; line in the main exchangewith a called line in the branch exchange, a switch control relay in said connector, a battery feedi relay? in said repeater, means for connecting said relays in a parallel; bridge 7 across the called end of the said trunlc'npon a connection toa called lineebeing completed,

and means forrthendisconnecting said switch control relay. 1 f 8. Ina telephone- .system, aseriesof auto matic; switches and interconnecting trunk lines for extending atalking connection to; a calledi'line, one of said switches beinga final connector switch, a controlling-line relay in said connector in bridge of the associated trunk line, means for automatically reversing the line conductors of said trunk line when the connection to the called line is completed, means responsive to said reversal for disconnecting said line relay, and means for preventing the release of said connector after said line relay has been disconnected.

9. In a telephone system, a connector, a switch control relay in the connector controlled by the operator to cause said switch to select a subscribers line, open contacts at said'connector in the conductors leading to the wipers thereof, and a relay automatically controlled by the said switch control relay when the connection to the subscribers line is completed to disconnect said control relay and close'said contacts.

10. In a telephone system, two exchanges, a trunk line connecting said exchanges and terminating in a repeater in the first exchange, means including said trunk line and a connector in the first exchange for connecta trunk line connecting said exchanges and terminating in a repeater in the first exchange, means lncludmg said trunk line and a connector in the first exchange for connect-,

ing a calling line in the second exchange with a called line in the first, means for autoy matically reversing the line conductors of said trunk when the connection is completed,

a line relay in bridge of said trunk, a battery feed relay, and a polarized relay responsive to such reversal to cause the battery feed relay to be substituted for the line relay.

In witness whereof, I hereunto subscribe my name this 23rd day of October, 1925 JOHN WICKS.

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