US1108194A - Coin-controlled automatic telephone-exchange system. - Google Patents

Description

W. W. LBAGH. COIN CONTROLLED AUTOMATIC TELEPHONE. EXCHANGE SYSTEI.

APPLICATION FILED NOV. 1. 1906. v

Patented Aug. 25, 1914.

' men/wry ZQc'nfa'eZrZ 6122mm m, M 8 W WINFIELI) W. LEACH, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN.ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS. v

COIN-CONTROLLED AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Aug. 25, 1914.

Application filed November 1, 1906.- Serial No. 341,517.

tem wherein the interconnection of subscribers lines is governed by the tentative payment or deposit of a coin at the calling station, and the final disposition of such coin is determined by the response or non- .response of the called subscriber.

My invention contemplates an arrangement of circuits and apparatus whereby a subscriber initiatin a call is required to deposit a coin in a com collector at his station in orderto bring the calling device at his substation into the control'of the line selecting mechanism at the central otlice toconnect such line with the desired or called line. lVhen such selecting mechanism has connected acalling line with a called line, and the'called subscriberresponds by removing his telephone from'its hook, electromagnetic mechanism is placed in operative condition to automatically effect the final deposit of the coin in the collector at the calling station when the calling subscriber at the termination of the conversation hangs up his telephone. is busy, or the line is free and said subscriber fails to answer, means are provided whereby the calling subscriber may obtain the refund of the coin tentatively deposited. To this end I may provide a refund key which is operative to refund the coin only when the telephone at the calling station has been replaced on its hook after an unsuccessful attempt to obtain a connection, and which, when operated, transfers the coin into a refund chute leading to a refund tray on the outside of the coin collector.

A feature of my invention consists in the provision of means whereby when a calling line has been connected with a called line, the individual line selecting mechanism of said called line will be automatically disconnected from said line, and from the circult of the interconnected subscribers, In

In case the called subscribers line--- carrying out this object, I may provide a cut-off relay in association with each line, arranged to be operated only when the line is a called line, and only during connection of said called line with the calling line to disconnect the individual selecting mechanism of such called line therefrom.

I will describe my invention more particularly by drawing, w ich represents diagrammatically an automatic telephone exchange system embodying my invention, reserving, however, for-the appended claims a statement of the parts, improvements and combinations which I deem novel with me.

Referring to the drawing, two telephone lines are shown extending in limbs 1, 2, from substations, A, B, respectively, to a central office, where each line is provided with line selecting and connecting mechanism. I will describe in detail the circuits and apparatus associated with the line of station A, it being understood that the line of station B is equipped in exactly the same manner; and for convenience of description I will consider station A as the calling station and 'station B as the called station.

At the substation is provided the usual telephone apparatus in a bridge of the limbs 1, 2. A calling device 3 is provided at the substation, comprising a springactuated arm 4 adapted to be set in a position representing the number of the line wanted, or a digit thereof, and to be returned under the influence of a spring to operate a gear 5 ,tocause the same to intermittently close a pair of contacts 6, 7,a number of times according to-the adjustment of the arm 4. The arm 4 while away from normal position maintains open a pair of contact springs controlling the substation bridge of the line.

The contacts 6, 7, control the operation of the central office line selecting mechanism, these contacts being in turn controlled by a pair of normally-open contacts 8, 9, within the coin collector C,.which are closed by a coin when tentatively deposited by a subscriber. The contact spring 7 is connected to earth, and the contact spring 6 is connected with a conductor 10 which leads through contacts 8.

v 9, within the collector,-

to the limb 2 of the line. The coin collector shown, which forms no part of the present invention, is provided with an electromagnet 11 in a branch 12 exreference to the accompanying tending from the limb 1 of the line to earth. The said magnet is arranged to be unresponsive to the central office battery current, bu t to require a high voltage current for its operation. Said magnet is provided with an armature 13 mounted upon the return. pole piece 14 of the magnet before the core there of. The armature carries on one side of its pivotal point the coin-controlledcontacts 8, 9, while on the other side of said pivot the armature is provided with a pin 15 connected with a retractile spring 16,- the contact pins 8, 9 projecting within the coin chute in the path of a coin. A pin 17 also projects through a slot in the wall of the coin chute, and together with pin 8, is adapted normally to support a coin placed within the collector. Said pin 17 is mounted upon a flexible support 18 which may be attached in any desirable way to the frame of the collector, said support 18 being adapted to be engaged by the plunger or refund key 19. The plunger 19 is maintained in its normal position by a spring 20, and while in such position said plunger closes a pair of contact springs 21, 22 included in limb 2 of the line.

When a coin is placed within the collector, it engages the pins 17, 8, forcing said pin 8 into engagement with its contact 9, to complete the branch conductor leading to the interrupter. In case the coin is to be depos ited, the magnet 11 in attracting its armature 13 removes the pin 8 from the path of the coin, which thereupon falls into the chute 23 leading to the cash box. On the other hand, if a coin is to be refunded, the plunger may be operated and will engage and move the flexible support 18, removing pin 17 from the path of the coin, allowing the coin to fall into the refund chute 24. If the calling subscriber, after receiving a connection, attempts to regain his coin by pushing in the plunger, the initial movement of said plunger opens the contacts 21, 22 in the limb 2 of the line, which as hereinafter explained, will cause the operation of magnet 11 to deposit the coin.

At the central oflice, the limbs 1, 2 of the line pass through the armatures 31, 32, respectively, of cut-ofi relay 33, to the contacts 34, 35, upon the rotatable selector arm 36, the limb 2 extending through a condenser, armature 37 and its normally-open front contact of relay 38, through the armature 39 and back contact of relay 40, to the selector contact 35, while the limb 1 extends through a condenser, armature 41, and back contact of relay 40, to the contact '34. The third terminal 42 upon the selector arm is connected with a conductor 43 leading through the winding of relay 38 to ground, said relay 3 being preferably sluggish in its action. The contact arm 36 is arranged to sweep over terminals which may be connected with the telephone lines or with trunk lines leading to other selecting mechanism; In the present case, I have shown the terminals as representing telephone lines, that is, each line is provided with a set of three terminals, terminal 44 being connected with the limb l of the line, while the terminal 45 is connected with the limb 2 of the line. The local terminal 46 of the set is connected with the conductor 47, which leads through the cut-ofi? relay 33, to the free pole of grounded battery 48. The limbs 1, 2 of course are multiplied to contacts upon the different selectors S in the exchange.

The selector arm 36 is mounted upon a vertical rotary shaft- 49 provided with a ratchet 50 adapted to be engaged by a stepping pawl 51 operated by an electromagnet 52, said ratchet being provided with a retainin pawl 53 operated by a magnet 54. After the selector arm has been moved to the position opposite the desired set of line ing mechanism, is provided in a bridge 57 of the limbs 1, 2, of the line, said bridge also including a battery 58, having its negative pole grounded, and a relay 59, said battery being interposed between the relays 56, 59, with its positive or free pole connected with the limb 2 of the line. When the telephone is removed from its hook at the calling station A, a circuit is completed by way of the bridge 57 for the relays 56, 59 and current also flows from the tree pole of battery 58 through bridge 57, limb 2 of the line, through the substation bridge closed by the telephone switch 60, to limb l of the line, and thence to earth through branch 12, which includes electromagnet 11 of the coin collector. Such current, however, doesnot affect the magnet 11 of the coin collector. The relay 56 is provided with a sluggish armature 61, which is adapted when attracted to close a shunt 62 about the cut-off relay 33 of the calling lineto prevent its improper actuation if such line should be selected and tested by another line during conversation.

Line selecting 0pemt-i0n.The armature 63 of relay 56 controls the circuits of the selectin mechanism, the armature being connecte with the conductor 64, which extends to the free pole of battery 58, while the front contact of said armature is connected with a conductor 65, which leads through the retaining magnet 54 and stepping magnet 52 in series, through normally closed contacts 66, 67, controlled by relay 55, through the armature 68 and back contact of busy test relay 69, to earth.

A branch conductor 70 leads from conductor 65 through the winding of connecting magnet 55, through a pair of contacts 71, which are intermitt ntly made and broken by the armature bf the stepping magnet in its operation, back to the con ductor 65. Said contacts 71 are arranged to prevent, while being rapidly made and broken, the energizaticn of the connecting magnet55, but when the stepping magnet 52 remains energized for a period longer than the interval between steps, as when selection has been completed, the back contact 71 will slowly follow up and make contact with the front contact 71, and thereby reestablish the circuit through the connecting magnet 55, which, since the circuit is also closed through the armature 63 of the relay 56, causes the connecting magnet 55 to be energized. It is to accomplish the closure of the contacts 71 upon a prolonged energization of the relay 52, as just described, that the back contact 71 is arranged pivotally mounted as indicated upon the drawings. The magnet 55 is provided with an armature 72 connected by a conductor 73 with the said conductor 70.-

Said armature, when attracted, forces the shaft 49 downwardly, and engages spring 67 to separate the same from'its anvil 66,

to thereby complete, a circuit for magnet 55 independent of the contacts 71.

The calling subscriber at station A, in initiating a call, deposits a coin in the collector 'C, which falls upon the stops 17, 8, closing the contacts 8, 9. He thereupon operates the calling device to make and break the contacts 6, 7, a predetermined number of times, according to the number of the line desired, and a circuit is intermittently mad'e and broken for the relay 56 at the central oflice, said circuit extending from the free pole of battery 58, through relay 56, bridge 57, limb 2 of the line, contacts 8, 9, closed by the coin, through the contacts 6, 7, of the calling device. Relay 56, in vibrating its armature 63, intermittently makes and breaks a circuit cxtending from the free .pole of battery 58, conductors 64 and 65, through retaining magnet 54, and stepping magnet 52,

through the springs 66, 67, through the armature 68 and back contact of busy test relay 69 to earth. The retaining magnet 54 is operated to throw the pawl 53 into engagement with the ratchet 50, and also the stepping magnet 52 operates to rotate the shaft 49 and bring the selector arm into po sition opposite or over the set of terminals representing the line desired. \Vhen the contact arm 4 of the calling device returns to normal position, after operating contacts 6, 7, it closes again the metallic circuit of the limbs 1, 2, maintaining the relays 56, 59, energized, and current flows from the free pole of grounded battery.58 through con ductors 64, 65, 70, through connecting magnet through the contacts 71, which are now at rest, back to conductor 65, and thence to earth through the armature 68 and back connected with the limb. 1 of the line.

contact of relay 69. Su'liicient current now flows in this circuit to operate the connecting magnet 55, which attracts its armature 72, forcin the shaft 49 downwardly, and bringing the terminals 34, 35, 42, into engagement with the terminals 45, 44, 46, representing the called line.- The'armature 72 also engages contact spring 67 to separate the same from its anvil 66, and completes a completed from the free pole of grounded battery 48, through cut-ofi" relay 33 of the called line, conductor 47, terminals 46, 42, upon the selector, conductor 43, to earth through relay 38. In case the called line is free, the relay 33 is operated and disconnects from the called line its individual line selecting mechanism, but if said line is busy, by virtue of its being a calling line, the cutofl relay 33 will not be operated, due to the presence of the shunt 62 thereabout closed by its line selecting relay 56. In case the called line is already in use as a called line, the relay 33 will, of course, already have been operated.

Busy z est.The limb 2 of the line is normally open at the armature '37 and front contact of sluggish relay 38, which is included in the circuit above traced, and a testing conductor extends from the terminal 35 upon the selectorarm, through the limb 2 of the line to the armature 37 of relay 38, whose back contact is connected with a conductor 74 leading through a winding 75 of the busy test relay to earth. In case the called line is busy there will. 'bepotential upon the terminal 44 from the central ofiice battery 58 by way of the substation of the line, and current will flow through the testing conductor and winding '75 -of busy test relay. 69 to earth and energize said relay before the sluggish relay 38 has had time to respond to the current in the local circuit- 47-43 before traced. The relay 69 when thus energized 'attracts its armature v68, opening the circuit 6465-707365 of the connecting magnet 55, and allowing the selector mechanism to be restored to normal condition by means of a suitable spring. Said relay 69 is also provided with an armature 76, which is connected with a conductor 77 leadin to the front contact of an armature '78 o? relay 56, said armature 78 being The front contact of armature 76 of relay 69 is connected with a conductor 79 which leads through the winding 80 of relay 69, through the secondary winding of a busy tone apparatus 81, to the free pole of grounded battery 82. And when said relay 69 is energized, due to said testing current, and the armatures are given their initial attractive movement, current flows from the free pole of grounded battery 82 through the winding 80 of said relay, armature 78 and front con-- The subscriber, upon hearing the busy tone in his telephone, hangs up his receiver and thereby causes the deenergization of relay 56, which retracts its armatures, the armature 78 opening the locking circuit of the busy tone relay 9 and restoring the same to normal position.

Calliny a free h'nc where subscriber (mswers.-In the present condition, when the contacts upon the selector rest in engagement with the terminals of the called line, there is no potential present upon the contact terminal 44, and the testing conductor receives no current; the sluggish relay 38, however, which is included in the local circuit 43-47, completed by contacts 42, 46, is operated, and cuts ofl? the conductor 74, which includes the winding of the test relay, from the limb 2 of the line, at the same time completing the continuity of said limb. The relay 38 is provided with an armature 83 which is connected to ground, the front contact of said armature being connected with a conductor 84 which leads through the relay 40 to the free pole of a grounded battery 85, and said relay 38,

' when attracted, in case the called line is free, completes a circuit to operate relay 40, which thereupon attracts its armatnres 39, 41, whose front contacts form the terminals of a conductor 86, including a ringing generator 87 and the winding 88 of a relay 89. Thus, when the relay 40 1s energized,.ringing current flows from the upper pole, for example, of'the generator 87 throu h the armature 41' and front contact of re ay 40, line conductor '1, contacts 34, 45, upon the selector, limb 2 of the called line, thence through the bell at the substation of the called line, back over limb 1 of'the called line, through the contacts 44, 35, of the selector, limb 1 of the calling line, armature 39 and front contact of relay 40, through the winding 88 of the relay 89, to the lower pole of the generator 87. The relay 89 is arranged to be unresponsive to the current flowing in the circuit just traced, owing to the high resistance in the line at the substation, but when the called subscriber responds by removin his telephone from its hook, a shunt is esta lished about the bridge containing the bell and condenser at the substation, and the winding 88 is enabled to energize the magnet 89 sufliciently to attract its armatures 90, 91. The armature 90 of relay 89 is included in a conductor 100, which leads from the free pole of grounded battery 85, through a low resistance winding 92 of relay 89, while the front contact of said armature is connected with a conductor 93, which leads through the armature 94 and front contact of relay 59 to the bridge 57 and earth. The conductors 100, 93 and 57 act as a shunt about relay 40, to cause the same to retract its armatures 39,

'41, and break the ringing circuit above traced, the relay 89 being locked up by means of its winding 92 included in said shunting circuit. A bridge 95 of the limbs 1, 2, of the line is provided between the condensers and the contacts upon the selector, said bridge containing a battery 96 between impedance coils to furnish the talking current required by the called station for transmission purposes.

Deposit of the coin.-The armature 91 of the relay 89 is arranged to be sluggish in its movement, said armature being connected,with a conductor 97 leading through the back contact of armature 78 of relay 56 to the limb 1 of the line, while the front contact of said armature 91 is connected with a conductor98 leading through a generator 99 to earth. when the relay 89 is operated upon the response of the called subscriber, the armature 91, in responding, places" the generator 99 in condition to operate the magnet 11 to deposit the coin when the calling subscriber at the termination of the conversation hangs up his telephone. lVhen the calling subscriber hangs up his telephone the relays 56,59, are deenergized to break the locking and connecting circuits above traced, including the locking circuit of relay 89. But the armature 91 of relay 89, being sluggish, remains in its attracted position for an instant after the retractive movement of the armature 78 of relay 56, whereupon current flows from generator 99 by way of conductors 98, 97, limb 1 of the line, through the electromagnet 11 of the coin collector to earth. This current causes the electromagnet 11 to attract'its armature 13, removing stop 8 from the path of the coin, which thereupon falls into the depositing chute 23.

Refund of c0z'n.1n case the called subscriber is busy, or fails to answer, the calling subscriber may hang up his telephone and operate the plunger 19, which will engage the flexible support 18 and remove pin 17 from the path of the coin, which thereupon falls into the refund chute 24. If the calling subscriber, after the called party answers, attempts to regain his coin by operating the plunger, the initial' movement of said lunger opens the springs 21, 22, break: ing t e line circuit and causing the denergization of the relay 56, whose armature 78 in its retractive movement completes a circuit from the generator 99 by way of con ductors 98, 9?, limb 1 of the line, branch 12 to earth through the coin collector magnet 11, which thereupon operates to deposit the coin.

It will be understood, of course that various forms 'of coin collectors may be used with the system of my invention. It should also be stated that while several batteries are shown, for convenience of illustration, a single central battery-may be employed.

I claim:

1. The combination with a calling and a i called telephone line extending from substations to a central oflice, of a toll device at the substation of the calling line, auto matic means at the central oflice for uniting said lines, operable from the'calling station, upon the tentative operation of said toll device, and automatic means for finally comleting the cycle of operations of said toll (evice, controlled jointly in the response of the called subscriber and in the replacement of the calling subscribers telephone.

2. The combination with a calling and a 4 called telephone line extending from substations to a central oflice, of,a toll device at thecalled subscriber,

the substation of the calling line, automatic line selecting mechanism at the central ofiice operable upon the tentative operation of said toll device for uniting said lines, a magnet for said toll device connected with the calling line adapted to finally complete the cycle of operations of said toll device, a relay at the central oliice, an operative circuit for said relay controlled in the response of a source of current for operating said ma net, and means controlled jointly by said relay andin the restoration of the calling station apparatus to normal condition, for connecting said source of our rent with the line to operatesaid magnet.

3. The combination with a calling and a called telephone line extending from substations to a central office battery, of a switch at each substation controlling the line circuit thereof, a toll device at the substation of the calling line, automatic line selecting mechanism at the central oflice, operable upon the tentative operation of said toll device for uniting said lines, a magnet for said toll device connected with the calling line adapted to finally complete the cycle of operations of said toll device, a source of current. for operating said magnet, a relay in the calling line circuit responsive to said substation switch, an armature for said relay, a relay having a sluggish armature, an operative circuit for said relay completed upon the response of the called subscriber, and

means actuated upon the attraction of the sluggish armature, and the retraction of the armature of said first-mentioned relay, when said substation switch is opened, for connecting said source of current with said line to operate said magnet and complete the cycle of operations of said toll device.

4. The combination with a calling and a called telephone line extending from substations to a central otfice battery, of a switch at each substation controlling its line circuit, a relay at the central oflice in the line circuit of said calling line, a toll device at the calling station, automatic line selecting mechanism at the central. ofiice operable upon the tentative operation of said toll device, for uniting said lines, an

elctromagnet for said toll device connected with the calling line and adapted to finally complete the cycle of operations of said to'll device, a relay at the central ofiice operative upon the response of the called subscriber, a source of current for operating said electro-m'agnet, a conductor for connecting said source with the line to operate said electromagnet, and contacts for closing saidconductor, actuated upon the operation of said last-mentioned relay and the quiescence of the relay in the calling line circuit.

5. The combination with a calling and a called telephone line extending from substations to a central office, of a toll device at the substation of the calling line, automatic line selecting mechanism at the central oflice, operable from the calling station upon the actuation of said toll device thereat, a source of ringing current, automatic mechanism actuated when said lines are united for applying said ringing current to the called line, and automatic means operated upon the response of the called subscriber, for cutting off said ringing current from the called line.

6. In a telephone exchange system, the combination with a calling and a called telephone line extending from substations to a central oflice, of a tolldevice at the substation of the calling line, automatic line selecting mechanism at the central oflice operable from the calling station upon the operation of said toll device at the calling station for uniting said lines, a source of ringing current, and means automatically actuated when said line selecting mechanism connects with the called line for applying said ringing current thereto.

7. In a .telephone' exchange system, the combination with a calling and a called telephone line extending from substations to a central oflice, of a toll device at the substation of the calling line, automatic line selecting mechanism at the central ofiic'e operable from the calling station upon the operation of said toll device at the calling station for uniting said lines, a source of ringing ourrent, means automatically actuated when said line selectin mechanism connects with the called line tor applying said ringing current thereto, and means automatically operated upon the response of the called subscriber for cutting off said ringing current from the'line.

8. The combination with a calling and a called telephone line extending from substations to a central ofiice, of a toll device at the station of the calling line, automatic line selecting mechanism at the central oflice operable from the station of the calling line upon the tentative operation of said toll device thereat for connecting said lines, a source of ringing current, means automatically operated when connection is made with the called line for connecting said ringing current wit-h said line, means operated in the response of the called subscriber for cutting oii said ringing current, and means controlled in the response or non-response respectively of said called subscriber to govern diiferent final operations of said toll device.

9. The combination with a calling and a called telephone line extending from substations to a central office, of a toll device at the substation of the calling line, automatic line selecting mechanism at the central ofiice operable from the calling station upon the tentative operation of said toll device thereat for uniting said lines, a source of ringing current, means automatically operated upon the connection of said lines for applying said ringing current to the called line, means operated in the response of the called subscriber for disconnecting said ringing current from the called line, means controlled jointly by the response of the called subscriber and the restoration of the apparatus of the calling substation to normal position for finally completing the cycle of operations of said toll device, and a refund key operative in case the called subscriber fails to answer or his line is busy.

10. In an automatic telephone exchange system, the combination with a calling and a called telephone line extending from substations to a central ofiice, of a toll device at the station of the calling line, automatic mechanism at the central office for uniting said lines, controlled from the calling station upon the tentative operation of said toll device, and means, actuated upon the replacement of the telephone at the calling station, at the termination of conversation, for efi'ecting the final operation of said toll device.

11. In an automatic telephone exchange system, the combination with a calling and a called line, of a toll device at the station of the calling line, automatic mechanism at the central oflice for uniting said lines controlled from the calling station upon the tentative operation of said toll device, means controlled in the response of the called subscriber for determining the final operation of said toll device, and means operable by subsequently replacing the receiver on the hook at the station of the calling line for efi'ecting such final operation of said toll device.

12. In an automatic telephone'exchange system, the combination with a calling and a called line extending from'substations-to a central oiiice, of a toll device at the substation of the calling line, automatic means.

at the central otlice operable from the calling station upon the tentative operation of said toll device for uniting said lines, automatic means for controlling the completion of the cycle of operations of said toll device upon the response of the called subscriber, and a refund key 'for producing such final o eration of said toll device when actuated a ter the response of the called party, and for producing a different operation of said toll device when operated prior to the respone of the called party.

13. The combination with a calling and a called telephone line extending from substations to a central office, of a toll device at the substation of the calling line, automatic line selecting mechanism at the central ofiice, a'toll deviceat the substation of the calling line, means controlled by the tentative operation of said toll device at the calling station for governing the operation of said selecting mechanism by the calling subscriber to connect said telephone lines, automatic means controlled in the response of thecalled subscriber for finally completing the cycle of operations of said toll device and manual mechanism operable independently of the receiver hook at the substation of the calling line for controlling the final operation of said toll device, said mechanism operating as a refund device when actuated prior to the response of the called party.

14. In a telephone exchange system, the combination with a calling and a called-telephone line extending from substations to a central ofiice, of a toll device at the substation of the calling line, automatic line switching mechanism at the central office, for uniting said lines, operable upon the tentative operation of said toll device, a source of ringing current, means automatically operated when the switching mechanism unites with a called line, for applying said ringing current thereto, means automatically operated when the called party responds, adapted to cut oil said ringing current, and mechanism controlled jointly by said means and by the calling party for completinggthe cycle of operations of said toll device.

15. In a telephone exchange system, the

combination With a calling and a called tele phone line extending from substations to a central office, of a toll device at the substation of the calling line, automatic line switching mechanism at the central office, for uniting said lines, operable upon the tentative operation of said toll device, a source of ringing current, means automatically operated when the switching mechanism unites with a called line, for applying said ringing current thereto, a relay in said ringing circuit unresponsive to the normally high resistance at the called substation, and responding to the decreased ,resistance in the circuit when the called subscriber answers, means controlled by said relay, for cutting off said ringing current from the called line, and means actuated by said relay for controlling the completion of the cycle of operations of said toll device at the calling station. i

16. In a telephone exchange system, the combination with a calling and a called telephone line extending from substations to a central oflice, of a toll device at the substation of the calling line, automatic line switching mechanism at the central ofli'ce, for uniting said lines, operable upon the tentative operation of said toll device, a source of ringing current, means automatically operated When the switching mechanism unites with a called line, for applying said ringing current thereto, a relay in said ringing circuit operated upon the response of the called subscriber, for cutting off said ringing current from the line, a locking circuit for said relay controlled jointly by said relay and the callin partys telephone hook, and means actuate by said relay for controlling the operation of said toll device.

In Witness whereof, I hereunto subscribe my name this nineteenth day of October WINFIELD WV. LEAOH. Witnesses:

IRVING MACDONALD, ALFRED H. MOORE,

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