US1502877A - Automatic telephone system - Google Patents

Description

Jill 29 1924; 1,502,877

A. J. RAY

AUTOMATIC TELEPHONE SYSTEM Filed Feb 23. 1921 4 Sheets-Sheet 1 53 W in 15 34/ Inuan mr.

July 29. 1924.

A. J. RAY

AUTOMATIC TELEPHONE SYSTEM I Filed Feb. 23'.

1921 4 Shg ts-Sheet 2 fi'zuenlmr 'Hf'fhur JHE July 29 192$.

7 AV .1. RAY

AUTOMATIC TELEPHONE SYSTEM 4 Sheets- Sheet 5 Filed Feb. 23. 192] Imafi 1:1r

July 29 1924. 1,502,877

A. J. RAY I AUTOMAT I C TELEPHONE SYSTEM Filed Feb. 23, 1921 4 Sheets-Sheet 4 Patented July 29, 1924.

UNITED TEES PATENT OFFICE.

ARTHUR- J. BAY, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Application filed February 23, 1921. Serial No. 447,011.

To all whom it may concern:

Be it known that I, ARTHUR J. RAY, a citizen of the UnitedStates of America, and a resident of Chicago, Cook County, and State of Illinois, have invented certain new and useful Improvements in Automatic Telephone Systems, of which the following is a specification.

My invention relates in general to an improved automatic telephone system, and more specifically to improved apparatus for use in a system where multiparty lines are employed and where the lines are provided with repeating coils individual thereto. In such a system, it will be seen that it is necessary to disconnect the repeating coil from a line when a call is extended thereto and to provide a direct path for generator cur rent to the bells of the called line.

Among the objects of my invention are, therefore, to'provide improved circuits and devices for accomplishing the above result without the use of complicated mechanism such as has been used in the past, and to provide certain details and minor features of improvement in connection with the above features which will be pointed out more clearly in the following specification.

I have chosen to illustrate my invention in connection with a multiparty line system of one specific type, but it should be under stood that the features of this invention may be applied as well to any well known type ,of party or straight line telephone system in which it may be desired to disconnect certain apparatus such as a repeating coil from a line when connection is made therewith.

In the drawings I have shown, in Figures 1, 2, 3, and 4, sufficient of the circuit diagrams and apparatus to fully illustrate my invention.

Fig. 1 shows a selector-repeater B which is individual to a line having connected thereto substations A and A. It will be understood that although only two substations are shown there may be 10 or 12 on a line each having its individual code signal which will later be described. The selector repeater B is of well known type but modified to illustrate the features of my invention.

Fig. 2 shows a connector which is of the well known Strowger type being modified to operate in conjunction with code selecting and ringing equipment shown in Fig. 3.

Fig. 3 shows a code selecting switch F, a code interrupter I, and a code ringing swltoh K Fig. 4 shows my invention applied to a simple repeater D on the called line, which repeater is controlled over a simplex circuit. This repeater is individual to the called subscribers line and between the line and its line switch C. The line switch C is of a well known rotary type although the Keith type might be used. The subscribers stations are of the same type as shown in Fig. 1 having the magneto for calling parties on their own line.

I will now point out the features of my invention by describing the operation of the system when a call is extended from one line to another. Let us assume that a subscriber at substation A (Fig.' 1) wishes to communicate with asubscriber at substation E (Fig. 4). The subscriber at A would remove his receiver thereby allowing his receiver-hook to assume an intermediate or listening position in contact with only spring 62, whereupon the subscriber would listen in to ascertain the condition of the line. Should he hear conversation on the line he will hang up the receiver without interfering with the conversation of the other party on the line. Should he have removed the receiver during a period between codes of a call being extended on his line, he would hear an audible signal or occupancy tone and would know that a call was already being eXtended-on his line, whereupon he would hang up his receiver. Now should he remove his receiver and find the line idle he would operate the arm N to allow the receiver hook to also engage with springs 21 and to cut in the talking circuit, and

extend ground over both sides of the line to the line relay of the selector repeaterB, over a simplex circuit. traced as follows: ground, springs 85 of the calling device (CD), springs 21, windings of the ringer magnets 22 in parallel over both sides ofthe line, break springs of relay 2, windings 3 and 5 of the induction coil, conductor 54, winding of relay 6, to grounded battery. Relay 6 will energize over this circuit, thereby closing a circuit for relay 10, traced from ground, springs 26 and 24, springs 31 of relay 4, windingof relay 10 to battery. Relay 6 also closes one point in a bridge of the talking circuit at springs 7 8 and 29 which will later be extended to the line relay 100 of connector H (Fig. 2). Relay 10 in operating closes a point in the vertical magnet circuit at springs 61 and extends ground to the private normal conductor 80 at working cont-act of springs 86 to make the line busy to other lines.

Assuming-that the substation wanted is number 12345. The subscriber will now operate his calling device to send out the desired numbers of impulses, thereby opening the circuit of the relay 6 at springs 85 the desired number of times. Each time relay (3 falls back a circuit is completed for relay 12 and vertical magnet 16 in parallel to step the switch to a desired level. Relay 12 is slow acting and therefore remains energized during the series of impulses. Relay 14 also energized immediately after the energization of relay 12 over a circuit traced from battery, winding of 14, oif normal springs 36 (the off normal springs having closed after the first vertical step) break springs 37 of relay 8, springs 33 and 32 of relay 12, and springs 35 of relay 10 to ground. A locking circuit for relay 14 isnow completed which may be traced from battery through winding of said relay, otl' normal springs 36, springs 38 of magnet 18, springs 46 of relay 14, and springs 53 of relay 8 to ground. Upon cessation of the series of impulses the relay 12 will fall back and in so doing will close a circuit for the: rotary magnet 18 which may be traced as follows: grounded battery, winding of magnet 18, make contacts 39 of relay 14, break springs 32 and 34 of relay 12, make springs 35 of relay 10 to ground. This circuit for the rotary magnet 18 is broken as soon as relay 14 falls back, the relay 14 having its locking circuit opened at springs 38 upon the operation of magnet 18, although springs 38 will again close springs 46 will remain open. The single rotary impulse of magnet 18 caused the wipers 41, 40 and 42 to be brought in contact with the first of a group of trunks leading to a group of connectorssimilar to the connector H, shown in Fig. 2. .If the first trunk is busy there will be ground present on th private wiper 40 which will furnish a new circuit for relay 14,-traced from battery, winding of relay 1.4, off normal springs 36, break springs 38 of magnet 18, springs 43 and 44 of relay 8, wiper 40 to the busy or grounded trunk. It will be seen that each time relay 14 energizes a circuit will be again completed for magnet 18 as before, each time that magnet 18 is energized the circuit of 14 will be broken at springs 38 of magnet 18. This action will continue until an idle trunk is found after which relay 1'4 willremain deenergized and the rotary motion of magnet 18 will be dis continued.

lVhen such idle trunk is reached relay 8 -144-146, inclusive.

which has previously been short circuited by ground on busy trunks, energizes over a circuit traced from battery, winding of relay 14, oft normal springs 36, springs 38 of magnet 18, cam springs 47, (cam springs are operated on eleventh rotary movement only) winding of relay 8, springs 35 of relay 10 to ground. Relay 8 is of higher resistance than relay 14 and therefore relay 14 does not energize at this time. Relay 8 in energizing operates to complete a circuit for relay 100 of connector switch H (Fig. 2) over a circuit traced from battery, upper winding of said relay, upper break contacts of relay 100, conductor 58, contact 49, wiper 41, springs 48, 29 and 78, windings 7 and 0 of the repeating coil, conductor 52, wiper 42, contact 55, conductor 69, lower break springs of relay 109, lower winding of relay 100 to ground.

The calling subscriber may now operate his calling device in accordance with the second digit of the desired number, and in so doing will again open the circuit of relay 6 the predetermined number of times. Relay 6 while operating maintains the relay 12 in operated position closing springs 51 to provide a direct bridge across the talking circuit, shunting the windings 7 and 9 of the repeating coil. Each time relay 6 deenergizes, the circuit of relay 100, which may now be traced through the direct bridge including the springs 51 of relay 12, is opened at springs 7 8 and 29.

At each interruption at the springs 78 and 29 the line relay 100 falls back and operates the vertical magnet 102 in series with relay 103, raising the switch shaft and wipers to the second level. Slow acting relay 103 is accordingly energized, and, in conjunction with the switching of the vertical otl' normal springs on the first vertical step, shifts the path of the impulses from the armature 151 of the line relay 100 so that they come through armature 124 and its working contact. lVhen the slow acting relay 103 deenergizes after the series of vertical impulses the impulsing circuit is shifted from the vertical magnet 102 to the rotary magnet 110.

In response to the calling of the third digit 3 of the called number, the rotary magnet 110 rotates the wipers 141-143, in elusive, into engagement with contacts Slow acting relay 114 is energized in multiple with the rotary magnet and remains energized during the entire operation. The operation now de pends upon whether the called line is busy or idle. If it is busy ground is present on test contact 145 and busy test relay 118 energizes over the following circuit: from grounded contact 145 through wiper 142, armature 115 and its working contact, armature 134 and its resting contact, and relay 118 to battery. When the slow acting relay 114 falls back, said relay 118 remains locked up over a circuit that includes its armature 130. The test relay 118 also opens the rotary magnet circuit at armature 111 in order 'to prevent further rotation of the wipers in case the calling dial is again manipulated, and at armature 119 completes a connection from the busy signalling machine to-the lower line conductor. This operation gives the calling subscriber an audible busy signal to inform him that the called line is busy, and he will hear the signal and replace his receiver.

Let us assume, however, that the called line is idle when the connector H is operated, as before explained, to establish connection therewith. Under these circumstances as soon as the slow acting relay 114 deenergizes upon the cessation of the rotary movement, the following circuit is completed: from ground through the working contact of armature 120 and said armature, armature 130 and its resting contact, upper winding of relay 117, resting contact of armature 115 and the said armature, test wiper 142, test contact 145, switching relay 271 of the called line switch C and through the stepping magnet 273 to battery. Relays 117 and 271 e11- ergize over the above traced circuit. Relay 271, upon enrgizing, removes the line relay bridge at the line switch C, while relay 117 locks itself to ground, completes at armatures 133 and 137 the connectionto the line wipers 141 and 143, and closes a circuit for relay 116 which operates to shift the operating circuit to conductor 176 leading to the code selector F.

In response to the fourth digit 4 of the called number the vertical magnet 201 of the code selector F receives four impulses over operating conductor 176. The first impulse comes through vertical off normal springs 211 and 209, slow acting relay 202 and vertical magnet 201 to battery. Upon the first vertical step the 0H normal springs operate and relay 202 energizes and completes a new path for the impulses as follows: from conductor 176 through off normal springs 211 and 210, armature 238 and its working contact, relay 202, and vertical magnet 201 to battery. The vertical magnet and the slow relay 202 receive three more impulses over the new circuit which stepsthe switch shaft and wipers up until they stand opposite the fourth level of bank contacts. Soon after thelast vertical impulse the slow acting relay 202 deenergizes and when it does so it switches the impulsing circuit to the rotary magnet 203 over the following path: armature 238 and its resting contact, armature 227 and its resting contact, slow acting relay 204 and through rotary magnet 203 to battery.

The calling subscriber may now operate his calling device in accordance with the last digit 50f the desired number. A series of impulses, as before, come over the operating circuit. In response to these impulses the rotary magnet operates to step the wipers 234 and 235 into engagement with the fifth set of contacts in the fourth level, opposite which they were previously raised. Relay 204 is energized in series with the rotary magnet 203 and at armature 225 closes a circuit for relay 205 which energizes and locks itself to conductor 173 and thence through the resting contact of armature 128 and said armature, armature 123 and its working contact to ground. At armature 227 relay 205 opens the circuit for the rotary magnet; however, relay 204 at armature 224 previously closed a multiple circuit so that the rotary magnet circuit is held closed until the end of the last impulse when it is opened by the falling back of relay 204, which prevents further rotation of the wipers in case the calling subscriber should again operate his calling device. Relay 205, upon energizing, also closes at armature 223 a circuit for the interrupter I. Relays 261, 262, and 263 receive a momentary impulse. Relays 263, 262, and 261 open the circuits of relays 262, 261, and 263, respectively. Relay 261, being of the ordinary quick acting type, falls back first and closes again the circuit for relay 263. Relay 263 remains energized for a time and holds the circuit to relay 262 open. Relay 262, upon deenergizing, closes again the circuit for relay 261 which operates and breaks the circuit for relay 263 which, upon deenergizing, closes again the circuit for relay 262. This operation continues until ground is removed from conductor 239 and, as relays 262 and 263 are both slow to fall back, the relay 261 is e11 ergized and dcenergized at intervals, thus sending out interrupted ground at armatures 212, 219, and 220.

Relay 204, upon deenergizing after the last rotary impulse, completes the following circuit: from interrupted ground, conductor 213, through the resting contact of armature 221 and said armature, working contact of armature 222 and said armature, and stepping magnet 214 of code sending switch K. As soon as ground issent over this circuit the stepping magnet 214 energizes and when the ground is removed magnet 214 deenergizes. Stepping magnet 214, upon deenergizing, advances the switch wipers 236 and 237 into engagement with the first set of contacts 227 and 228 of their associated banks. Vipers 236 and 237, upon. reaching contacts 227 and 228, complete the following circuit: from grounded contact 228 through wiper 237 conductor 206, wiper 236, conductor 240, relay 231, and resistance R to battery. Relay 231 energizes over the above traced circuit and locks itself to ground over ground conductor 173. Relay fifth contact set current flows from- 231 upon energizing completes the following circuit for the slow relay 286 of the repeater D, to provide a direct, circuit for ringing current to the called line, ground spring 233, conductor 17 5, upper winding of 'ring-cut-ott' relay 125, spring 126 and its back contact, springs 133, wiper 1 11, contact 1 11 conductor 117, springs 284C and 285 and relay 286 to battery. Relay 125 does not energize over this circuit due to the high resistance of relay 28b. Relay 286 upon energizing disconnects the windings 279 and 280 from the called line and closes a circuit including springs 288 and 289 and their front contacts including the condenser 290 thus preventing the ringing current from passing through the repeating coils. hen ground comes again over conductor 213 it operates stepping magnet 211 over its previously traced circuit and also operates ringing relay 217 over the following circuit: from ground over previously traced circuit to armature 222 and thence t-hrough the resting contact of armature 215 and said armature, armature 216 and its working contact, and relay 217 to battery. When relay 217 operates, its armature 218 shifts conductor 174 from ground at the signalling device Y to ground through generator G. Ringing currentfrom generator G flows over conductor 174, through the resting contact of armature 129 and said armature, armature 137 and its working contact, wiper 1&3, contactv 14:6, line conductor 148, spring 288 and its front contact through the stations E-E etc. in multiple, and back through spring 289 and its front contact, condenser 290, over line conductor 147, contact 1 14:, wiper 14t1, working contact of armature 133 and said armature, armature 126 and its resting contact, upper winding of ring cut-off relay 125, conductor 175 and armature 233 and its working contact to ground. All the bells on party line X are operated but relay 125 is not operated, due to its design and adjustment. Vhen ground is removed from conductor 213, relay 217 deenergizes and shifts conductor 17 1 back to ground through device Y'and the stepping magnet 211 deenergizes to step the wipers onto the second set of contacts. hen ground is again placed on conductor 213 relay 217 operates to connect generator on the called line and the stepping magnet attracts its armature and when the ground is removed from conductor 213 relay 217 shifts its armature from generator to ground and the magnet 211 releases its armature to step the wipers 236 ant. 237 onto the third set of bank con- 'tacts. This process continues until the bells on party line X have been rung four times and the magnet 214 has been deenergized to step the wipers from the fourth to the fifth set of contacts. hen the wipers reach the grounded conductor 206 through wiper 236, the fifth contact in the bank of said wiper, conductor 265, contact 243 in the fifth set on the fourth level of the bank of code selector F, wiper 23 1, and relay 232 to battery. Relay 232 energizes over this circuit and at armature 215 opens the circuit to ringing relay 217. Vhen ground is again placed upon conductor 213 stepping magnet 21 1 operates as before but obviously relay 217 cannot operate, as its circuit is open at armature 215 and therefore, the bells on party line X are not rung. However, when stepping magnet 21s: deenergizes and steps the wipers 236 and 237 into engagement with the sixth set of contacts relay 232 falls back and reestablishes the circuit for relay 217. W hen ground is again. placed upon conductor 213 the bells on the called line are rung as before. The effect of energizing relay 232 is to cause a time interval of break to occur in the regular periodical rings sent out to the called line so as to distinguish between the first digit of the code and the second. Now it will be seen that the bells on party line X have been rung four times and after a short interval they have started ringing again. As pointed out, the bells are rung while the wipers are on the sixth set of contacts and they will continue to ring each time the interrupter I places ground on conduct-or 213 until the eleventh contact set is reached, when the bells will have been rung live more times thus completing the code call l-5. When the wipers are stepped onto the eleventh contact set current flows from grounded conductor 206 through wiper 236 and the eleventh contact in its associated bank, conductor 2G6, contact 2 1% in the bank of the code selector F, wiper and resistance R to battery. This circuit shunts the relay 231 and allows it to fall back and when it does so it opens its locking circuit, opens the circuit of ringing relay 217, and at arn'iature places battery on conductor 175 through resistance R. It will be seen that when relay fell back the circuit of the slow relay 286 of repeater D was opened at spring and said relay will deenergize after an interval and restore the connections of the repeating coil windings 279 and 280 to the called line. Also when relay 217 deene'rgizcs, ground is fed to the called line through a winding of an induction coil in the device Y to place a significant tone on the called line. This is done to indicate to any subscriber who may listen in at this time that a call is in progress and the line in use. This occupancy tone is placed on the called line through the windings Y278 and 277 of the repeater D and through condenser 282. Relays 281 and 286 being both deenergized at this time. Vhen the stepping magnet energizes and deener-- gizes again the wipers 236 and 237 are advanced to the twelfth contact but the bells on the party line X are not rung because the circuit for ringing relay 217 is open and it cannot, therefore, place generator on the line. In case the called subscriber does not respond immediately, the code sending switch K continues to rotate step by step and repeats the code as it passes over the remainder of the contacts, because the first contact is multiplied with the thirteenth, the second with the fourteenth, etc. The switch K will continue to rotate step by step and the proper code will continue to be sent out on the party line X until the called subscriber answers.

If the called subscriber answers at the end of the code the relay 231 will at that time be in deenergized condition and the.

following circuit for the relay 281 will be closed at springs 291 of the called line, ground through the calling device, springs 291, the coils of the ringer in parallel, two sides of the line and windings 279 and-280 in parallel and through relay 281 to battery. Relay 281 upon energizing closes the following circuit for the ring cut-off relay 125. From ground through resting contact of armature 218 of relay 217, of switch F, conductor 174,- springs 129, springs 137, wiper 143, contact 146, repeating coil windings 278 and 277, springs 283 and 284, conductor 147, contact 1 1 1, wiper 141,.springs 133, springs 126, relay 125, conductor 175, springs 233 and its resting contact to battery through resistance R. Relay 125 energizes over the above traced direct current circuit, locks itself at armature 127 to grounded conductor 177, extends the called line to the back bridge relay 109, and at armature 128 it disconnects conductor 173 from grounded conductor 173.

As soon as the wipers 236 and 237 are stepped onto either the twelfth or the twenty-fifth contact set in their associated banks, no ground will be present on conductor 206, for the energization of relay 125 removed ground from conductor 173.

Relay 205 accordingly deenergizes, removes ground from starting conductor 239, opens the interrupter ground at armature 222fin case the interrupter I should be operating due to some other call, and closes at armature 226 and its resting contact a point in the release circuit.

Returning now to the. connector, when the called line is extended to the back bridge relay 109 the talking circuit is completed. Relay 109 is energized while the receiver at E remains off the hook and reverses the direction of current flowing in the dialing loop of selector repeater B. This operation is of no utility in the present disclosure, but on'account of its being a standard operation the circuits are shown in this Way.

I Conversation may now take place over the established connection and when it is finished both subscribers replace their receivers. The release of the equipment is brought about by the replacement of the receiver at the calling substation A which opens the circuit for the line relay 6 at springs 21. Relay 6 upon deenergizing opens the circuit of relay 10 and closes one point at springs 26 and 27 in the circuit of release magnet 20 which circuit is completed when relay 10 falls back and closes'spring 61 with its back contact. Release magnet 20 energizes and restores the selector repeater B to normal. Relay 6 upon deenergiz'ing also opens the circuit of relay 100 of the connector H at springs 78 and '29. The falling back of relay 100' is followed by the deenergization of release relay 101 which removes ground from the release circuit for connector H andcode selector F The deenergization of these relays completes a circuit for the release magnet 190 of connectorH and for release magnet 221 of the selector F. This circuit may be traced from ground through armature 151 and its resting contact, armature 122 and its resting contact, conductor 171, resting contact of armature 226 and. said armature, conductor 172, and in multiple through 011 normal springs 208 and 207 and release magnet 221 of code selector F to battery, and off normal springs 107 and 108 and release magnet 190 of connector H to battery. The release magnets 190 and 221 energize overthe above traced circuit and restore their respective switches to normal.

It could be shown how any one of a plurality of combinations is sent out, but it is thought that with the explanation already given, an examination of the drawing (Fig. 3) will clearly show how many codes may be sent out on any party line that appears in the banks of connector H.

As previously pointed out, during the time that the relay 231 of code selector-F is energized, the return path of the generator is connected to ground at armature 233. Ring cut-off relay 125 of the connector H, included in the circuit of relay 286 and' for ringing current, can energize only when direct current of a definite value flows through it, and since relay 231 does not deenergize until the end of the code, suflicient direct current cannot flow through the circuit due to the high assistance of relay 286, and the ring-cut-oif relay cannot energize to break the ringing current. As before pointed out, the deenergization of relay 231 ends the last digit of the code and upon deenergizing, it connects battery at armature 233 through resistance R to the circuit, so that should the called subscriber have hisreceiver off the hook or if he removes it before relay 231 energizes again to repeat the code, direct current flows over the circuit previously traced for relay 125, which energizes and completes the talking circuit in a manner already explained. The code ringing switch K, however, does not stop as soon as the called party answers but continues to advance step by step until the wipers reach one of their normal positions. Should the called party answer before the end of his code, all the bells on the line will continue to ring until the code is completed, due to condenser 290 preventing them from being shunted at the called station. Upon the code being completed relay 2S6 falls back to extend the talking circuit to the called stationand to allow the energization of relay 281 to complete the previously traced energizing circuit of the ring-cut-ott relay 125.

It the called subscriber does not respond, the calling subscriber will hang up and he is likely to do so while the code is being sentout. It the code should be stopped immediately when the calling subscriber hangs up, many times the last code would be that of some other subscriber and not the one that is wanted. In the present disclosure, however, the code will be completed even though the calling subscriber does hang up his receiver before its completion. Upon referring to the drawings, it will be seen that neither the connector H nor the code selector F can release and that code sending switch K cannot stop until relay 205 of se lector F deenergizes. Now when the calling subscriber hangs up and allows relays 100 and 101 to deenergize ground is removed from conductor 173 at armature 123, but ground is kept on conductor 1'73 from wiper 237, over conductor 206, working contact of armature 228 and said armature. This ground holds relays 117, and 205 energized until the wipers of switch K reach the twelfth. or twenty-fifth contact set. IVhen they do so the code has been finished, ground is no longer present on them, relays 117 and 205 deenergize, and switches F and 11 release in the usual manner.

It should be understood that, although the calling line here shown is equipped with a selector repeater individual thereto and the called line has a repeater and a line switch individual to it, any line may be equipped with either type of circuit desired and will operate in the manner contemplated by my invention, that is, the repeater D is in all respects similar to the corresponding parts of the selector repeater B except in one case a line switchis directly controlled by the repeater, while in the other case a selector is directly controlled by the repeater. I will now describe in general the operations ensuing when a call is made to a line such asthat having sta tions A, A, etc., merely to show the similarity of the two repeaters.

In case a call is made from any other line in the system to the line A then a connector, similar to H will make contact with normals 79, 80 and 81 or line A in the same manner that connection was extended to the normals 144:, 145 and 14-6 of the line X, ex cept of course that the code selecting mechanism would be operated in accordance with the code of the line A. In this case, relay 2 of the selector repeater B will be operated when the relay 231 of the code selector F energizes. Relay 2 operates to close the springs 13 and 15 and springs 23 and 82, thereby disconnecting the repeating coil windings 3 and 5 from the called line and providing a direct path for signalling current from normal conductor 79, through condenser 83, springs 15 and 13 through the ringers of the stations in parallel and back over the other side of the line through springs 23 and 82 and to the other normal conductor 81.

It will thus be seen that I have provided a very simple arrangement for cutting off the repeating coil from a line when connection is made thereto, without the use of tuned relays or other complicated mechanism, and for providing a direct path for ringing current to the bells of that line with no shunting paths to weaken the strength of the ringing current.

Having fully described and ascertained the featuresand aspects of my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

lVhat I claim as my invention is:

1. In a telephone system, a line, a connector switch having access to said line, means for operating said connector to extend a connection to said line, a relay in said connector and a relay individual to said line, said individual relay energized in series with said other relay by direct current, means in said connector for supplying ringing current to said line through the winding of said relay in the connector, and contacts on said individual relay for closing the ring ing circuit.

2. In a telephone system, a line, a connector switch having access to said line, a relay in said connector, another relay, a winding of said first relay acting as a conductor for ringing current supplied to said line by said connector, and at the same time acting as a conductor for operating said other relay, contacts on said other relay for extending a ringing circuit to said line, and a third relay operative when the called subscriber answers to permit the operation of said first relay.

3. In a telephone system, a called subduring the ringing perlod.

4. In a telephone system, a line, a repeat ing coil having windings normally in bridge of said line, a connector for seizing said line, a ring cut ofl relay in said connector, a second relay connected in series with said cut oil relay when the line is seized and adapted when operated to cut off said repeating coil and to complete a ringing circuit to the called line, and means operative when the called subscriber responds for cutting off said second relay and for completing an operative circuit for said first relay.

5. In a telephone system, a line, a repeater individual to said line, a connector for seizing said line, means associated with said connector for applying ringing current to the line when called, a pair of relays associated with said repeater, a ring cut off relay included in the ringing circuit, means for rendering one relay of said pair responsive to the seizure of the line to disconnect said repeating coil and to complete the ringing circuit, and the other relay operative on the response of the called subscriber to complete an operating circuit for said cut oil' relay.

In witness whereof, I hereunto subscribe my name this 9th day of February, A. D., 1921.

ARTHUR J. RAY.

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