US1721748A - Automatic telephone system - Google Patents

Description

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AUTOMATIC TELEPHONE SYSTEM Original Filed July 8. 1921 3 Shletkshew um .E MM@ wm mm MW www@ mlm E WJ G. RICHARDSON ET M. MM'MW AUTOMATI C TELEPHONE SYSTEM my w,

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AUTOMATIC TELEPHONE SYSTEM 3 Smets-sheet wh En Original Filed July 8. 1993 Ear ne? ENF:

Patented July` 23, 1929.

UNITED STATES A 1,721,748 PATENT OFFICE.

RODNEY Q. RICHARDSON AND JOHN E. GARDNER, OF CHIOAGO, ILLINOIS, ASSIGNORS, BY RIESNE ASSIGNMENTS, TO .A UTOMATIG ELECTRIC, INC., OF CHICAGO, ILLINOIS,

.A OOBPORATION OF DELAWARE..

AUTOMATIC TELEPHONE SYSTEM.

Application tiled. July 8, 1921, Serial No. 483,333. Renewed February 19, 1926.

The present invention relates in general to automatic telephone systems, and is more particularly concerned with such systems as are usually installed in mercantile`- establishments and the like, and which are commonly known at private automatic exchanges.

More specically, the invention relates to the rovision ol improvements in the socallenl passing or transfer call service which Ila is used in systems of 'this character. Heretoiore, a nber ci assing call schemes have heen designed em odying a number of diderent principles of operation, and in the present invention still other novel operating lti principles are proposed which it is believed will render these systems more eihcient and practical and add to their commercial value.

'llhpere are other objects ci the invention not now speciiically mentioned which, to-

t@ ether with the foregoing, will be described ereinaiter with reference to the accompanying drawings. v

Referring now to the drawings, comprising Figs. 1, 2 and 3, therein -is shown b @t means of the usual circuit diagrams su cient of the apparatus of an automatic telephone system to enable the invention to be' readily understood. lin Fig. 1 is shown a two way trunk line comprising conductors au 50 and 51 incoming to a private automatic exchange from the main office. This trunk line extends through the repeater D and terminates in the incoming connector H, Fig. 2. The relay group D is a form of repeater at which is associated with the incoming connector H, and is used when a call is transferred from one party to another in the private. automatic exchange, and is also used on outgoing calls over the trunklne comtu prising conductors 50 and 51 to the main exchange.'

The incoming connector H, Fig. 2, is a switch of the usual Strowger type, the circuits of which have been slightly modified in accordance with the features of the present invention. The connector H has access to local subscribers lines, two of which are shown at A, Fig. 2, and A', Fig. 3.

These substatlons are of the usual. autoll matic type and are provided at the-exchange with the individual line switches C and C.

These line switches are of the well known rotary type, and in common with the other line switc es have access to trunk lines leading to local connectorswitches, one of these trunk lines being shown in the drawings terminating in the local connector H', Fig. 8.

The connector H', like the connector H, is of the well known Strowger type, and has the usual set of 100 bank contacts divided into ten rows, or levels. From the iirst nine levels of bank contacts the connector H has access to local subscribers lines in the same manner as has the'incoming connector H. From the tenth level the connector H has access to trunk lines such as the trunk line comprising conductors and 5l, Fig. 1, extending to the main exchan e. ln addition to the above, the connector is adapted to operate as a finder switch under certain conditions as will appear fully hereinafter.

@alle from/,the maia exchange to the private cinematic eme-harige.

Having briefly described the ap aratus shown in the drawings, a detailed description of its operation will now be given. For this purpose it will be assumed that a calling subscriber in the main exchange desires to call the subscriber at substation A, Fig. 2, in the private automatic exchange, and it will be assumed further thatthe callin subscriber has operated a series of se ector p latter relay, upon energizing, at its armature 139 .prepares the operating circuits of the incomingconnector H and at armature 138 places ground u on the release trunk conuctor 187 whic extends to multiple bank contacts in the banks of the local connector switches, such as bank contact 32() accessible to the connector H', whereby the two way trunk line comprising conductors 50 and 51 is prevented from being seized for an outgoing call to the main exchange.

The calling subscriber in the maia exchan may 110W Gperate his calling device 1n accor ance with the next digit of the desired number. By this operation a series of interruptions is produced in the circuit of the line re- 'an im ulse of current over the followin path: rom ground by way of armature 13 and its back contact, armature 139 and itsfront contact oi normal springs 169 and 168, through the winding of t e vertlcal magnet 166, and thence through the Winding of the slow acting relay 128 to battery. The

above is the circuit over which the first verti cal magnet impulse is sent, but u pon the first vertical. step of the switch the oil' normal springs are shifted and thefremammg 1mpulses tol the vertical magnet traverse a new circuit which is the same as the one rev1- ously traced, except that it includes t e o' normal springs 169 and 134, and amature 142 and its front contact, relay 128 being now in operated position. The vertical magnet 166 operates to raisel the switch wipers 170 to 173, inclusive, step by ste until they are placed opposite .the level o bank contacts in which is located the contact set associated with the line of substation A. The slow acting relay 128 is energized in series with the vertical magnet and retains its armature attracted throughout the vertical movement of the switch, and at the termination thereof deenergizes and transfers the operating circuit to the rotary magnet 167.

The calling subscriber may now o crate his hcalling device for the next and tina digit of his desired number. As before, a series of interruptions is produced i'n the circuit of the line relay of the selector repeater in the main exchange and these are 'repeated to the line relay 126 of the connector H. The line relay 126 retracts its armature a plurality of times in response to these interruptions, each time sending an impulse of current from ground by way of armature 137 and its back contact, armature 139 and its front contact, off normal springs 169 and 134, armature 142 and itsfback contact, through the winding of the slow acting relay 132, armature 149 and its back contact, back contact and armature 158,

and thence through the winding of the rotary magnet 167 to battery. The rotary magnet 167 operates to rotate the switch wipers 17 O to 173, inclusive, into engagement with the set of bank contacts associated with the line of the called substation A, which, we will assume, are the bank contacts 174` to 177, inclusive. The slow acting relay 132 energizes in series with the rotary magnet and operates at its armature 151 to connect the test wiper 171 to the test relay 131.

Assuming that the desired line is busy at test contact by way of the said test wiper,

conductor 102, back contact and armature 77, conductor 103, armature 151 and its front contact, and through the winding of the test relay 131 to battery. Relay 131, upon energlzing prepares a oint in its locking circuit at arniature 148 wliich is closed immediately upon the deenergization of the slow acting relay 132, and at armature 153 places a busy tone from the b machine on the lower heavy talking con uctor. The calling subscriber, being informed by this signal that the desired line 1s inaccessible at the present time, replaces his receiver, thereby releasin the operated switches in a manner which will be described hereinafter.

The above is the normal operation of the connectbr H when the called line is busy, provided that this line is not one of a group of lines. Should the line of substation A be one of a group of lines listed under the same telephone number, it will be necessary to change the circuits of theconnector H so 1as to enable it to select an idle line in the group of lines, or if all lines of the group are busy to return the busy signal to the calling subscriber. In order to effect these circuit changes the test contacts such as test contacts 175 and 176 of all the lines in the group except the last are connected together. Now when one of these grouped lines become busy there will be a ground potential present upon both the test contacts, such as 175 and 176. In order to describe the operation of the connectrr H under these conditions, it will be assumed that the line of substation A is one of a group of lines and it will, therefore, have its test contacts 175 and 17 6 connected together. Under these circumstances, immediv ately upon the connector H being operated into engagement with the bank contacts 174 to 177 inclusive, there being a ground potential on both the test contacts 175 and 17 6, the relay 131 will be energized as before described. Then, upon the deenergization of the slow acting relay 132, a circuit is completed which may be traced from grounded test contact 176, test wiper 172-, armature 150 and its back contact, back. contact and armature 156, armature 168 and its back contact, through the winding of relay 130 and thence through the winding of the slow acting relay 128 to battery. Both relays 128 and 130 are energized over this circuit. Relay 130, upon operating, establishes a locking circuit for itself at armature 146 which includes the interrupter contact 168 of the rotary magnet, and at armature 147 completes the rotary magnet circuit. Magnet 167 operates to rotate the switch wipers 170 to 173, inclusive, into engagement with the next set of bank bank contacts.

maintain the test wiper 171 1n engagement4 with the test relay 131. Should the subscribers line, associated with the next set of bank contacts, be busy also, the test relay 131 will be maintained energized. If this line is not the last one of the group the connector switch wipers will be rotated in thesame.

manner as was before described. However, if this line is the last one in the group no circuit will be completed for the stepping relay 130 as there will be no ground potential present upon the test contact engaged by the test wiper 172 and the connector l-l will remain in engagement with this set of bank contacts an transmit a busy signal to the calling subscriber.

llt will now be assumed that the line of substation A is idle, when the connector H is operated into engagement with its associated Under these conditions there will be no circuit completed for the test relay 131. Then, following the deenergization of the slow acting relay 132, a circuit is completed which may be traced from ground on conductor 169', by way of normally closed springs controlled by armature 141, armature 149 and its back contact, lower winding of the switching relay 133, back contact and armature 151, conductor 103, armatures 77 and 83 in multiple, conductor 102, test wiper 171, test contact 17 5, private normal conductor 29'?, through the winding of the switching relay 211 of the line switch C, and thence through the winding of the motor magnet 212 to battery. Both the relays 133 and 211 are energized over this circuit. However, due to a mechanical interlocking device controlled by the armature of line relay 210, relay 211 only partially attracts its armature, that is, enough to disconnect the line of substation A from its normal battery and ground connections in the line switch C. Relay 133, upon energizing, establishes a locking circuit for itself at armature 157, places direct ground upon the test contact 17 5 at armature 155, and at armatures 160 and 158 completes the ringing circuit. Ringing current from the generator lead is now intermittently applied to the line of substation A until the subscriber thereon responds. When this occurs, the ring cut-cti relay 129 will be energized over the called subscriber-s line loop. Relay 129, upon operating, establishes a locking circuit for itself at armature 144, at armatures 143 and 145 cuts oil the ring and at the front contacts of these armatures finally completes the talking connection. Conversation may now take place between the calling subscriber in the main exchange and the called subscriber at substation A, talking being su plied to the called subscriber from the win ings of the back bridge relay 125. Ill`he back bridge relay 125 is, of course, energized over the called line loop and operates to complete the circuit of the slow acting relay 61 in the associated repeater D. Relay 61, upon energizing, prepares certain circuits the operation of which will be described shortly.

Tram/ier of calla. Under certain conditions the called subbattery scriber at substation A may find it necessary to call another subscriber in the private automatic exchange for the calling party. As suming that it is necessary to call the subscriber at substation A', Fig. 3, the subscriber at substation A will go through the same procedure as if initiating a local call, that is, he will replacehis receiver upon the switehhook and remove it and listen for the so-called trunk tone. The calling subscriber, upon hearing this tone, will operate his calling device for the two digits which constitute the number of the other private automatic exchange subscribers line, which operations will now be described. When the receiver is replaced at substation A the back bridge relay 125 is deenergized. lUpon dcenergizing, relay 125 opens the circuit of the slow acting relay 61. After the deenergization of the back bridge relay 125 and before the deenergization of relay 61, an impulse of current is sent to the slow acting relay 60. Relay 60, upon energizing, establishes a locking circuit for itself at armature 85, and at armature 84 prepares a point in the circuit of the relay 59. When 'the receiver is again removed at substation A, the back bridge relay 125 is cn- 'ergized and a circuit is completed which may be traced from ground byway of front contact and armature 135, conductor 106, armature 84 and its front contact, lower winding of relay 59, common conductor 95 and thence to battery by way of armature 97 and its back contact. Relay 59, upon energizing, establishes a locking circuit for itself at armature 7 8 which includes its upper winding and that of the common relay 96. Relay 96, upon en ergizing, removes battery from the common conductor 95 so as to prevent any interference in transferring calls, as will be apparent later. Another result of the energization of relay 59 is that ground is removed from conductor 186 which terminates in the bank contact 321 in the set of bank contacts associated with the outgoing multiple of the two way trunk line, comprising conductors 50 and 51, which is accessible to the local connector H. Another result of the energization of relay 59 is that at armature 81 a release circuit is prepared for releasing the connector H. A still further result of the energization of relay 59 is that at armature 7 7 ground is removed from the test contact 175 but as relay 59 also opens the locking circuit of the slow acting relay at armature 8O ground is replaced upon the test contact 175 after a short interval.

During the interval that ground is removed from the test contact 175 the relay 211 in the line switch C deenergizes and as the receiver is removed at substation A the line relay 210 immediately energizes. Relay 210, upon operating, at armature 214 completes a circuit which includes the switching relay 211 and the motor magnet 212 in series, and at its armature 215 connectsV the test wiper 221 t0 the above circuit at a point midway between the switching relay and the said motor magnet. The operation ofthe line switch C now depends upon whether the trunk line, the bank contacts of which its wipers are associated with, is busy or not. If this trunk line is busy, the test contact engaged by the test wiper 221 will be grounded and the motor magnet, being supplied with direct ground via the said test wiper, will operate as a buzzer to advance the switch wi ers 220 to 222, inclusive, step by step until t eyare rotated into engagement with an idle trunk line. However, it will be assumed that the trunk line with which the switch wipers are associated when the line relay 210 energizes is idle, and it will be assumed further that this trunk line is the one shown in the drawings terminating in bank contacts 223-225, inclusive. Under these conditions the relay 211 will be energized. Relay 211, upon operating, disconnects the line yconductors 205 and206 of the substation A Jrom the winding of the line relay 210 and :Ercan ground, respectively, and extends them by way of armatures 216 and 218, wipers 220 and 222, bank contacts 223 and 225, trunk conductors 189 and 191, normally closed springs controlled by armatures 262 and 263 to the up er and lower windings of the line relay 251 oi) the local connector H. During the interval that the line switch C is operating the relay 60 in the repeater D is deenergized and a ground potential will be replaced upon the test contact 175, this serving to maintain the switching relay 211 energized after the deenergization of the slow acting relay 210.

The line relay 251 of the local connecter H is energized over the line loop of the substation A and operates at its armature 264v to complete the circuit of the slow acting relay 252. Relay 252, upon energizing, at armature 288 prepares the operating circuits of the connector H and at armature 266 places ground upon the release trunk conductor 190 extending back to the line switch C through the winding of the slow acting relay 269. However, switching rela 211 is held energized by the ground potential on the private normal conductor 207 and as relay 269 is short circuited it will not energize in series with the switching relay 211 of the line switch C.

A circuit may now' be traced extending from ground by way of back contact and armature 295, armature 265 and its front contact, back contact and armature 348, s ring 346 and its resting contact, and t rough the winding of t-he vertical stepping relay 253 to batteryly Relay 253, upon energizing, at armature 268 sends an impulse of current over the following circuit: from ground by way of front contact and armature 268, ofi normal sprin s 273 and 272, through the winding of the s ow acting relay 256 and thence through the winding of the vertical magnet v306 to battery. Magnet-306 operates to raise the switch wipers 315 to 318, inclusive, one ste and at armature 348 opens the circuit of t e stepping relay 253, which deenergizes, openin the circuit of the vertical magnet 306, w ich deenergizes also. The stepplng relay 253 will be immediately energized again and will operate as before to again complete the vertical magnet circuit. However, the circuit over which the vertical magnet is energized is slightly difierent than before traced inasmuch as the oi normal springs are now operated and the circuit for the vertical magnet includes the oii normal springs 273 and 274 and armature 286 and its front cont-act, relay 256 now being energized. The alternate operation of the stepping relay 253 and the vertical inagnet 306 will continue until the switch wipers are raised opposite the tenth level of bank contacts. The springs 345 to 347, inclusive, are shaft springs which are adapted to be operated when the switch wi ers are brought opposite the tenth level o bank contacts. This may be accom lished by any suitable cam arrangement. en these springs are operated the circuit of the stepping relay 253 is opened and the vertical operation of the connector H ceases. It will, of course, be un- 'nsy derstood that the slow actin relay 256 maintains its armatures attracte throughout the vertical movement of the switch. By the engagement of spring 347 with its working contact a circuit 1s completed extending from ground by way' of sprlng 347 and its working contact, through resistance 278 and thence through the upper winding of relay 254 to battery. Relay 254, upon ener ing, completes a circuit which may be traoerom ground by way of front contact and armature 266, front contact and armature 277 ,f armature 285 and its front contact, back contact and armature 308, and thence through the winding of relay 258 to batter Relay 258, upon energizing, establishes a ocking circuit for itself at armature 292, and at armature 293 prepares the rotary ma et circuit. Short y after the termination o the vertical movement of the switch the slow acting relay 256 deenergizes, thereby completing the -rotary magnet circuit. Magnet 307 operates to rotate the switch wipers 315 to 318, inelusive, into engagement with the first set ot bank contacts in the tenth leve1 and at armature 308 opens the circuit oi' the stepping relay 258. The slow acting relay 257 is energized in series with the rotary magnet and operates at its armature 290 to connect the tcst wiper 317 to the test relay 258. lt will be noted that all the conductors associated With the incoming trunk line similar to conductor 186 are normally grounded in the repeaters, such as D. However, in the repeater D the relay 59 is energized and ground is removed trom the multiple bank contacts in which the conductor 186 terminates which in the switch itl is the bank contact 321. llt the lirst trunk line in the tenth level with which the switch Wipers 315 to 318, inclusive, are novv associated is other than the multiples ot the one shown in Fig. 1, there will be a ground potential present upon the test contact engaged by the test vviper317 and the stepping relay 258 vvillbe again energized. ltelay 258, upon energizing, completes its locking circuit at armature 292 and at armature 293 completes the circuit ot the rotary magnet. 'lhe rotary magnet 307 operates to rotate the switch Wipers into engagement with the neat set ot bank contacts in the tenth level and at armature 308 opens the locking circuit of the stepping relay 258 which deenergizes opening the circuit ot the rotary magnet which deenergizes also. 'llhe alternate operation of relay 258 and the rotary magnet 307 will continue until the switch "Wipers are rotated into engagement with the bank contacts associated With the outgoing multiples ot trunk line shown in lig. 1, the test contact 321 ot Which is ungrounded. When the switch Wipers are brought into engagement with the bank contacts 319 to 322, inclusive, there will be no circuit completed tor the stepping relay 258. rl`hen, following the deenergization of the slow acting relay 257, a circuit is completed which may be traced i'rom ground by Way ot' the iront contact and armature 266, armature 292 and its back contact, lovver Winding ot the switchingrelay 260, back contact and armature 290, normally closed springs controlled by armature 296, test Wiper 317, test contact 321, conductor 338, conductor 186, conductor 110, armature 79 and its front contact and thence through the Winding of the slow acting relay 58 to battcry. Both relays 58 and 260 are energized over this circuit. Relay 58, upon energizing, establishes a locking circuit for itself at armature 71 to ground on conductor 110, at armature 7 0 completes the circuit ot the slow acting relay 63, and at armature 71 completes a circuit which extends from ground by Way oft front contact and armature 7 d, armature 81 and its front contact, conductor 111, ed normal spring 124; and its Working contact, and thence through the Winding ot the release magnet 165 to battery." Ma et 165 operates to restore the connector l to normal.

The line and release relays 126 and 127 however remain energized as long as the calling subscriber in the main exchange has his receiver oit the hook. The `spring 123 is adapted to be controlled by both the vertical and release magnets, that is, as soon as the vertical magnet operates spring 123 engages its Working contact, while as soon as the ren lease magnet enerizes the spring 123 breaks away trom its woifking contact. rlhis maybe accomplished by placing the sprin 123 on the double dog or the connector llpon the spring 123 breaking away trom its Work 111g contact, the locking circuit ot the rela" s 129 and 133 are opened and these relays eenergize, thereby disconnecting the Wipers trom their connections in the connector lll. litelay 63, upon ener izing, removes ground trom the normally c osed springs controlled by armature 72 ot' relay 58 so as to enable the local connector ll to be released under certain conditions, as will more fully appear hereinafter. as soon as the relay 157 in the incoming connector l-ll deenergizes, the ciru cuit of the back bridge relay 125 is opened and this latter relay then deenergizes. lUpon i'etracting its` armature 136, relay 125 opens the circuit oit the slovv acting relay 61 and before the latter relay deenergiaes sends an impulse oi' current to the slow acting relay 60. rll`he operation ot relay 60 is but momentary and has no function at this time. lltelay 61, upon deenergizing, transfers the locking circuit oi relay 58 to the release trunk conductor 109 at armature 87 and at armatures 88 and 89 prepares certain circuits Whose function will appear later. Returning now to the operation of the local connector lil", when the svvitch Wipers were raised opposite the tenth level the spring 34.5 engaged its Working contact thereby preparing a circuit for the relay 250. Relay" 260, upon ener-- gizing, establishes a locking circuit tor itselt at armature 301, also at this same armature short circuits the relay 269 included in the circuit which supplies ground to the holding circuit for the line switch C in order to pre- A vent the relay 269 energizing immediately upon the release ot the incoming connector' l-l, and connects ground to the test Wiper 317 115 at armature 300. Another result of the en gagement et armature 301 with its Working contact is that the circuit of relay 250 is completed. The latter relay, upon energizing, disconnects the local trunk conductors trom 12o the windings ot the line relay 251 and extends them by Way ot armatures 262 and 263, Wipers 315 and 318, bank contacts 319 and 322, conductors 336 and 339, conductors 185 and 188, conductors 101 and 113, to the upper and 125 lower windings of the line relay 56 of the repeater D. Relay 56, upon energizing, completes the circuit of its associated slow acting relay 55. The latter relay, upon energizing, prepares the operating circuits of the con- 130 tery.

nector H at armature 65 at armature 67 opens the locking circuit of t e relay 59, and also that of the common relay 96, and at the front contact of this armature places ground upon the conductor 110 thereby establishing a holding circuit for rela s 260 and 250 in the local connector H and a so the relay 211 in the line switch C in order to maintain the connector' und line switch in their operated positions. As the circuits of relay 59 and 96 are now open these relays will deenergize. Relay 96, upon deenergizin again places batter upon the common con uctor 95, thereby al owing any other party to pass a call. Relay 59, upon deenergizing, laces an additional ground upon the con uctor 110 at armature 79 and its back contact, which may be traced from ground by way of armature 88 and its back contact, armature 72 and its front contact, back contact and armature 79 to conductor 110, and at armature 61 opens the circuit of the release ma et of the connector H.

The above operations wherein the line switch C selects an idle local connector and that connector switch operates as a finder to ind the particular incoming trunk line takes but a very short interyal of time, and, immediately upon the line of the subscriber at substation A' being extended to the line relay 56 of the re eater D, a trunk tone is given to the subscriber from the trunk tone machine by way of normally closed springs controlled b armature 159, conductor 112, normally closed springs controlled by armature 92, through the lower winding of the line relay 56 to conductor 188; This tone is audible to the subscriber at substation A and notifies him that everything is in readiness to pass the call.

The subscriber at substation A may now operate his calling device in accordance with the first digit of the desired local subscribers number, which in this case it will be assumed is that of the substation A. By this operation a series of interruptions is produced in the circuit of the line relay 56 of the repeater D and this relay deenergizes a plurality of times in response thereto. At the retraction of its armature 69 an impulse of current is sent over the following circuit: from ground by way of armature 69 and its back contact, armature 65 and its front contact, back contact and armature 91, conductor 104, oii' normal springs 169 and 168, winding of the vertical magnet 166 and thence through the windin of the slow acting relay 128 to batn the same manner as was before described, the magnet 166 operates to raise the switch wipers 170 to 173, inclusive, step by step until they are placed opposite the level of bank contacts in which is terminated the line of the desired substation. Slow acting relay 128 is energized in series with the vertical magnet and being slow acting maintains its armature attracted throughout the vertical movement of the switch, and at the ter'- mination of thevertical operation deener- 'zes and transfers the impulsing circuit to t e rotar ma net 167.

The su scri er at substation may now operate his calling device for the next digit of his desired number. As before, the line relay 56 retracts its armature a plurality of times in response to the interruptions in its line circuit but this time the successive deenergizations of the line relay 56 are e'ective to send impulses of current to the rotary magnet 167. Magnet 167 now operates to rotate the switch wipers into enga ement with the bank contacts associated wit the line of the desired called substation, which we will assume are the bank contacts 178 to 181, inclusive, associated with the line of the substation A. The slow acting relay 132 energizes in series with the rotar magnet and v operates to connect the test wiper 171 to the test relay 131.

Should the desired line be busy, the test relay 131 will be energized and will operate as before described to give a busy tone to the calling subscriber. Upon being informed by this tone that the desired line 1s inaccessible, the subscriber at substation A may converse with the calling subscriber and ascertain if another line will do. Should this be the case the subscriber at substation A will then replace his receiver upon the switchhook, thereby opening thecircuit of the line relay 56 at the repeater D. The latter relay, upon deanergizing, opens the circuit of the slow acting relay 55 which deenergizes after a short interval, thereby completing a circuit which may be traced from ground by way of arma ture 69 and its back contact, armature 65 and its back contact, armature 75 and its front contact, back contact and armature 89, conductor 111, 0E normal spring 124 and its working contact, and thence through the winding of the release magnet 165 to battery. Magnet 165 operates in the usual manner to restore the connector H to normal, the line and release relays 126 and 127 remaining energized as previously pointed out. Thelocal connector H and the line switch C are not released at this time as conductor is supplied with ground by way of armature 72 and its front contact over a circuit which may be traced from ground by way of armature 88 and its back contact, armature 72 and its front contact, back contact and armature 7 9 to conductor 110. When the subscriber at substation A again removes his receiver the line relay 56 will be energized to complete the circuit of the slow acting relay 55 in the usual manner. The connector H may nov: be reoperated by th f-f subscriber at substation A in the same manner as was before described, it being noted that immediately upon the slow acting relay 128 energizing that the locking circuit of test relay 131 is opened and the mamas busy tne removed from the lower heavy talkino conductor.

hould the calling subscriber hang up during the interval when the subscriber at substation A had his receiver' upon the switchhook the line relay 126 would deenergize and open the circuit of the slow acting relay 127. llelay 127, upon deenergizing, would remove ground from the release trunk conductor 109 and at armature 140 would complete the circuit of the release magnet 165. By the opn eration or magnet 165 the connector lll would be restored to normal. As ground is removed from the release trunk conductor 109, the locking circuit ol the slow acting relay 58 in the repeater l) is opened and this relay would deenergize opening the circuit of the slow acting relay 63. During the interval alter the deenergization el relay 58 and before the deenergization of relay 63 ground is removed trom the conductor 110. llpon ground being removed from holding conductor 110, the relays 250 and 260 in the local connector ll would deenergize as would the switching re- `lay 211 of the line switch C. llpon relay 250 deenergizing the connector H would be re stored to normal by the release magnet 309. Relay 63, would deenergize after a short in terval and again Iround conductor 110. ln`

this manner all t e apparatus would be released.

However, it will be assumed that when the connector ll is operated into engagement with the bank contacts 178 to 181, inclusive, the associated line is idle. llnder these conditions there will be no ground potential present upon the test contact 179 engaged by the test wiper 171 and no circuit is completed for the test relay 131. Then, following the deenergization of the slow acting relay 132, the switching relay 133 of the connector ll and the switching relay 341 o'l the called line switch C', Fig. 3, associated with the substation A', are energized in series. Relay 341 operates in the usual manner to disconnect the line of the substation A from its normal battery and ground connections to the line switch C. Relay 133, upon energizing, operates 1n the usual manner to establish a locking circuit for itself and complete the ringing circuit. Another result of the energization of relay 133 is that the trunk tone is removed from the line of substation A so as not to interfere with the conversation. li the subscriber at substation A fails to answer, the subscriber at station A may of course replace his receiver and release the connector H 'the same as in the case when the called line is busy, after which he can reoperate the conlay 125 is energized over the called subscribers line loop and operates to complete the circuit of the slow acting relay 6l. Relay 61, upon energizing, transfers the locking circuit of the slow acting relay 58 from the release trunk conductor 109 to the holding trunk conductor 110 at armature 87, and at armature 88 removes one ground from the trunk conductor 110. However, as the relay is energized at this time this removal of ground at armature 88 has no eect. 'lhe conversation may now take place between the calling subscribers in the main exchanee and the subscribers at substation A and su station A.

Should the subscriber at substation' A desire to retire from the conversation at any time, he may do so by merely replacing the receiver on the switchhoolt. Upon so doing, the circuit et the line rela 56 is opened and this relay deenergizes andl opens the circuit of the slow acting relay 55. Relay 55, upon deenergizing, removes ground from the holding trunk conductor 11() at armature G7. By this operation the circuits of the relays 250 and 260 in the connector H and the relay 211 in the line switch C are opened and these relays deenergize. As before, relay 250, upon deenergizing, completes the release magnet circuit of the connector switch lll.

ln this manner the connector ll and line switch C are restored to normal. As ground is removed from the holding trunk conductor 110, the locking circuit of the slow acting relay 58 is opened and this relay deenergizes and opens the circuit of the slow acting relay 63. The latter relay, upon deenergizing, again places ground upon the conductor 110. When the conversation is iinally terminated between the calling subscriber in the main exchange and the second called subscriber at substation A', the calling subscriber will replace his receiver upon the switchhook and release the connector H as before described and the operated switches in the main exchange will be restored to normal in the well known manner.

1t will be apparent that the subscriber at substation A after being called by the subscriber at substation A can, after the subscriber at A has retired from the connection, in turn pass the call in the same manner as was before described.

Should the subscriber at substation A be very busy he might not have the time to transfer the call to another private automatic exchange subscriber and under these conditions he will hang up his receiver and remove it again and wait until he hears a *rival nn tnw 'nnlfxinlfx lxn m11 v'nnnnnl- #La calling subscriber to call the private automatic exchange subscribers number to which the call is desired to be transferred. By these operations the connector H will be rethe desired number.

leased by the subscriber at substation A and 1re-operated under the control of the calling wsubscriber in the usual manner.

It will be remembered that during the interval that the local connector H was operating as a finder the relay 59 in the repeater l) was energized in series with the common relay 96. Now should another party in the private automatic exchange attempt to pass the call during this interval he will be una o do so'until the connector H has established connection with the trunk line. This operation will now be brieiy described. For this purpose it will be assumed that the relay 96 is energized when the subscriber at substation A attempts to pass the call. When the subscriber at substation A replaces his receiver the relay 60 is energized as before described and operates to establish a locking circuit for itself and to prepare the energizing circuit of the relay 59. When the receiver is again removed at substation A the relay 59 is not energized as there is now no battery on the common conductor 95, the relay 6() therefore remains locked energized. The line switch C does not operate at this time as the relay 59 is deenergized and the test contact 175 remains grounded. Now as soon as the local connector operating as a finder iinds the incoming trunk line, the relay in the associated repeater which corresponds to the relay 55 in the repeater D will energize and open the circuit of the relay similar to relay 59 and that of the common relay 96. When relay 96 deenergizes battery is again supplied to conductor 95 and the rela 59 will be energized and the operations will proceed as before. During the short interval that the apparatus is not functioning the subscriber at substation A hearing no trunk tone will not operate his calling de-v vice. The relay 96, therefore, prevents any interference which might arise should two local connector switches be operating as iinders at once.

LocaZ connections between subscribers in. Hw private automatic escolta/nge.

Having described how calls incoming from the main exchange may be transferred from one party in the private automatic exchange to another, the manner in which certain local connections in the private automatic exchange are established will now be briefly described. For this purpose it will be assumed that the subscriber at substation A desires to call the subscriber at substation A. Under these conditions the subscriber at substation A will remove his receiver and operate his calling device in accordance with the digits of When the receiver is removed at substation A the line switch C operates in the usual manner to extend the associated line to an idle local connector switch, which, we will assume; is the connector switch H.

The line relay 251 is immediately energized over the callin line loop and operates to comlete the circuit of the slow acting rela 252.

elay 252, upon energizing, prepares tile operating circuits of the connector H at armature 288 and at armature 266 com letes a holding circuit for the line switch which may be traced from ground by way of front contact at armature 266, through the winding of the low resistance slow acting relay 269, release trunk conductor 190, bank contact 224, test wiper 221, armature 217 and its front contact, through the winding of the switching relay 211 and thence through the winding of the motor ma net 212 to battery. It will be understood t iat this holding circuit is completed before the slow acting rela 210 has had time to deenergize. A branc of this holding circuit also extends by way of the private normal conductor 207 to multi led bank contacts in the banks of the local an incoming connector switches which have access to the line of substation A whereby the said line is protected from intrusion in the usual manner. Relay 269 is ener ized in series with the switching relay 211 o the line switch C and operates at armature 295-to open the circuit or' the stepping relay 253 and at armature 267 closes the circuit of the slow acting relay 259. The latter relay, upon energizing, at armature 296 cuts o' the test wiper 317 and places the test wipers 316 into operative relation with the switch circuits, and at armature 298 connects the trunk tone to the callin subscribers line. Before proceeding furt er, it will be well to note certain adjustments of the armatures on the slow acting relay 252and the armatures on the slow acting relay 269. Armature 266 is adjusted to engage its working contact a short interval before the armature 265 engages its working contact, while on the relay 269 the armature 295 is adjusted to break away from its resting contact before the other two armatures are operated. The reason for this adjustment is to prevent the stepping relay 253 from energizing and starting the automatic vertical operation of the switch.

By the trunk tone si al the calling subl scriber is notilied that e may now operate his calling device. By this operation a series of interruptions is produced in the circuit of lthe line relay 251 and this relay retracts its armature 264 a plurality of times each time sending an impulse of current over the following path: from ground by way of the said armature and its back contact, armaturel 261 and its back contact, armature 288 and its front contact, olf normal springs 278 and 274, through the winding of the slow acting relay 256, and throu h the winding of the vertical magnet 306 to atter The above is the circuit over which the rst impulse to the vertical magnet is sent, but upon the first vertical step of the switch the off normal springs are shifted and the remaining impulses are sent lll weaves to the vertical magnet over a circuit which is the same as the one` previously traced except that it includes the ed' normal springs 27 3 and 27d and armature 236 and its iront contact, relay 256 being now energized. Magnet 306 -operates in the usual manner to raise the switch wipers 315 to 313, inclusive, step by step until the are placed opposite the desired level or ank contacts. I'lhe slow acting relay 250 is energized in series wit-h the vertical magnet and operates in the usual rent to the rotary magnet 307. Magnet 301" operates to rotate `the switch wipers step by step until they are placed in engagement with the set of banlr contacts associated with the line ot substation A", which we will assume are the bank contacts 3274330, inclusive, 'llhe slow acting relay 25?l is energized in series with the rotar magnet and operates toconu nect the test wiper 313 to the test relay 253.

lf the desired line is busy, relay 253 will be energized in the usual manner; Relay 253, upon operating, prepares a point in its locln ing circuit at armature 292 and at armature 29d places the busy tone on the lower heavy talking conductor. ly this signal the calling subscriber is notilied that the desired line is busy and he may replace his receiver upon the switchhook, thereby releasing the operated switches in the usual manner.

lt will now be assumed that the line ol substation ll is idle, when the wipers of the conu nector ll are brought into engagementwith the bank contacts 327-330, inclusive. Under these conditions therewill be no circuit comn pleted for the test relay 253. Then, lcllowing the deenergization ol the slow acting relay 257, the switching relay 260 is energized in series with the switching relay 341 oil the line switch C. Relay 34:1 operates to disconnect the line of the substation il trom its normal battery and ground connections in the line switch C. Relay 230, upon energizing, establishes a locking circuit tor itself at armature 301, 'at armature 30d removes the trunk tone from the subscribers line and at armatures 305 and 303 completes the ringing circuit. 'lhe slow acting relay 269 remains energized throughout the connection as the armature 301, upon engaging its front contact, cannot short circuit the relay as the slow acting relay 259 is energized. Ringing current from the generator lead is now intermittently applied to the line of substation A' until a response is obtained. -When the called Y subscriber answers the ring cut-oil relay 255 is energized over the called line and operates to establish a locking circuit for itself at armature 280 and at armatures 279 and 281 cuts oli' the ring and at the lliront contacts of these armatures finally completes the talking connection. Conversation may now be carried on between the calling and called sub scrlbers over the heavy talking conductors, talking battery being su plied to the calling subscriber from the windings ol the line re lay 2 51 and to the called subscriber trom the widings of the bach bridge relay 25d.,

hen the conversation is completed both subscribers will replace their receivers upon their respective switchhoolrs. lllhen the rem ceiver is replaced at substation it the con nector lil is released in the usual meer, an is the line switch C.

Ucmcctioaa ,from the 30M/vate automatic can change to the mai/n, ewcltcagc..

Having described the operation ol the connector ll when a local subscriber is called, its operation when a call is made to a. subscriber 1n the automatic main exchange by way ol one ot the incoming two way tr lines will now be described brielly. lor this purpose it will be assumed that the subscriber at substation A desires to entend a connection to a subscriber in the main exchange. its the outgoing multiples ot these trunlr lines terminate in the tenth level oil bank contacts in the local connector switches he will remove his receiver and operate his calling device lor the digit 0. When the receiver is removed substation A,1ine'switch 1G operates in the man..I

ner previously described to entend the line oil' substation t to an idle local connector switch, which, we will assume, is the connector switch l-l. l'n response to the operation ol the call ing device tor the digit 0 the wipers ot the connector switch l-l are raised under control of the line relay 251 and the vertical magnet 306 until they are brought opposite the tenth level ol bank contacts. lllhen 4the switch wipers are brought opposite the tenth level the springs 345 to 3l?, inclusive, are operated inthe usual manner. lBy the engagement ot spring 3/1-7 with its worlring contact relay 25d is energized and, as the slow acting relay 256 is also energized, it operates to complete the circuit of the stepping relay 253. Shortly alter the termination ont the vertical movement ot the switch the slow acting relay 256, which was energized in series w1th the vertical magnet, deenergizes and completes the circuit or the rotary magnet 307. Mag net 307 operates to rotate the switch wipers into engagement with the set ot bank contacts associated with the rst trunk line in the tenth level. 'llhe trunk selecting operation of the connector H will take place in the usual manner, that is, the stepping relay 253 and the rotary magnet 30'? will be alternately energized until the test wiper 316 engages the ungrounded test contact, which we will assume is the test contact 320 of the contact dll llldl lllll lllli llltl set 319 to 322, inclusive. When this occurs there will be no circuit completed for the stepping relay 258. Then, following the deenergization of the slow acting. relay 257, the switching rela 260 is energized over a circuit which may e traced from ground by way of front Contact and armature 266, ar1.na ture 292 and its back contact, lower winding of the switching relay 260, back contact and armature 290, front contact and armature 296, test wiper 316, test contact 320, conductor 337, conductor 187, armature 138 and its back contact, conductor 105 and thence through the winding of the slow acting relay 62 to battery. Relays 260 and 62 are energized over this circuit. Relay 62, upon energizing, disconnects the 1ncoming trunk conductors 50 and 51 from the windings of the line relay 126 of the incoming 'connector H at armatures 90 and 93, and at armature 92 places direct ground on the conductor leading to the lower Winding of the line relay 56 of the repeater D.

Returning to the operation of the connector H', relay 260, upon energizing, establishes a lockingcircuit for itself at armature 301 and at the same time completes the circuit of relay 250. Relay 250, upon energlzing, disconnectsthelineconductors of the callingsubstationA from the windings of the line relay 251 and extends them byl way of armatures 262 and 263, wipers 315 and 318, bank contacts 319 and 322, conductors 336 and 339, conductors 101 and 113, and the upper and lower windings of the line relay 56 of the repeater D. Relay 56, upon energizing, completes the circuit of the slow acting relay 55 at armature 69. Relay 55, upon energizing, places ground on the release trunk conductor 109, thereby establishing a holding circuit for the connector switch H and the lineswitch C. A Another result of the energization of relay 56 is that a bridge is completed across the trunk conductors 50 and 51 which may be traced from the trunk conductor 50, arma ture 90 and its front contact, armature 68 and its front contact, winding of the impedance coil 57, and thence to trunk conductor 51. Upon this bridge being placed upon the trunk conductors 50 and 51 the line relay of the incoming switch in the main exchange is energized.

When the calling device at the calling substation is operated in accordance with the remaining digits of the main exchange subseribers number successive series of interruptions are produced in the circuit of` the line relay 56 of the repeater D. Byl means of armature 68 and its front contact these are repeated to the switches in the main exchange in order to completel the desired connection. The operation of the switches in the main exchange takes place in the usual manner.

When the connection is completed and the conversation terminated the subscriber at percatado eq; essaie.: cui 'V uop'eisqnsv the line relay 56 is opened and this relay de-t,

energizes opening the bridge across the trunk conductors 50 and 51 at armature 68 and at armature 69 breaking the circuit of the slow acting relay 55. By the removal of the bridge across trunk conductors 50 and 51 the release of the switches in the main exchange is initiated. Relay 55, upon deenergizing, removes ground from the release trunk conductor 109, thereby causing the release of the connector H and the line switch C.

Having fully described the features of the invention, what is considered to be new and desired to have protected by Letters Patent will be pointed out in the appended claims.

What we claim as our invention is:

1. ln an automatic branch exchange, incoming and local directively controlled connectors for use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange by means of one of said incoming connectors, and means including one of said local connectors for enabling the called subscriber to release and reoperate the incoming connector in use to transfer the call.

2 In an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange to one of said lines by means of one of said incoming connectors, and means including the line switch of the called line and one of said local connectors for enabling the called subscriber to reoperate the incoming connector in use to transfer the call.

3. In an automatic branch exchange. subscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to brahch and local connections, respectively, means for completlng a call from the main exchange to one of said lines by means of one of said incoming connectors, means including the line switch of the called line and one of said local connectors for enabling the called subscriber to reoperate the incoming connector in use to transfer the call, and means whereby the subscriber first called can disconnect his .line fromthe transferred connection after the sccond called subscriber has answered. V

4. In an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange to one of said lines by means of one of sai-d incoming connectors, means including the line switch llO avances vuse in establishing main to branch and local connections, respectively, means for complet-Y ing a call `from the main exchange to one of said lines by means ot one ont' said incoming connectors, means including the line switch of the called line and one ot said local connectors tor enabling the called subscriber to reoperate the incoming connector in use to transfer the call, and means tor enabling the called subscriber to transiter' the call to another line in case no answer is obtained tromv the line to which it is rst attempted to transiter the call.

ti. ln an automat-ic branch exchange., subscribers linesand individual line switches therefor, incoming and local connectors for use in establishing' main to branch and local connections, respectively, means for completing a call from the main exchange to one ot said lines by means ot one ot said incoming connectors, means including the line switch ot the called line and one of said local connectors for enabling the called subscriber to transfer the call, and means whereby the subscriber lirst called can disconnect his line trom the transferred connection after the second called subscriber has answered.

7. ln an automatic branch exchange, subscribers lines and individual line switches therefor', incoming and local connectors tor use in establishing main to branch and local connections, respectively, means for completing a call trom the main exchange to one oit said lines by means of one of said incoming connectors, and means whereby the called i subscriber can operate his. line switch and one of said local connectors to connect with the incoming connector in use in order to transfer the call.

8. ln an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors tor use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange lo one of said lines by means ot one of said incoming connectors, means whereby the called subscriber can operate his line switch and Ione of said local connectors to connect with the incoming connector in use over a new path, and means whereby the called subscriber can then release and reoperate such incoming connector to transfer the call.

9. ln an automatic branch exchange, sub- Yscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to branch and local connections, respectively, means tor completing a call trom the main exchange to one of said lines by means of one of said incoming connectors, means controlled automatically by the switch-hook at the called station for operating the line switch of the called line and one of said local connectors to connect with the incoming connector in use over a new path, and means whereby the called subscriber can reoperate such connector to transiter the call.

10. ln an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to branch and local connections, respectively, means for completing a'call trom the main exchange to one of said linesby means oli' one ot said incoming connectors, means responsive to the removal, the replacement, and the subsequent removal ont the receiver at the called station for oper ating the line switch ot the called line and one otn said local connectors to connect with the incoming connector in use over a new path, and means whereby the called subscriber can reoperate such connector to transt'er the call.

ll. ln an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors tor use in establishing main to branch and local connections, respectively, means tor completing a call 'trom the main exchange to one ot said lines by means ot one ot said incoming connectors, means whereby the called subscriber can operate his line switch and one ot said local connectors to cnnect withl the.

incoming connector in use over a new path, means whereby the called subscriber can then release and reoperate such incoming connector to transfer the call, and means whereby the subscriber lirst called can Idisconnect his line from the transterred connection by releasing his line switch and the local connector 1n use.

l2. ln an automatic branch exchange, sub scribers lines and individual line switches therefor, incoming and local connectors tor use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange to one ot' said lines by means ot one of said incoming connectors, means whereby the called suhscriber can operate his line switch and one of said local connectors to connect with the incoming connector in use over a new path, means whereby the called subscriber can then release and reoperate such incoming connector to transfer the call, means whereby the subscriber first called can disconnect his line from the transferred connection by releasing his line switch and the local connector in use, and means whereby the subscriber on titl the line to which the call has been transferred can operate his line switch and another local connector to connect with their incoming connector in use in order to transfer the call a second time.

13. In a telephone system, a connector switch, called lines accessible thereto, line switches associated with said calledI lines, trunk lines leading to other connector switches accessible to said line switches, means for operating said first mentioned connector switch into connection with one of said called lines, and means including the line switch associated with the called line and one of said other connector switches for releasing the rst mentioned connector switch.

14. In a telephone system, a connector switch, called lines accessible thereto, line switches associated with said called lines, trunk lines leading to other connector switches accessible to said line switches, means for operating said iirst mentioned connector switch into connection with one of said called lines, means including the line switch associated with the called line and one of said other connector switches for releasing the first mentioned connector switch, and means for reoperating said first connector switch nto connection with another of said called mes.

l5. In a telephone system, telephone lines, automatic switches, means including a series of said automatic switches controlled from a calling one of said lines for establishing a connection with a called one of said lines, means including another series of said switches for releasing said first established connection while maintaining a connection with said calling line, means Yfor then extending the connection to include another called one of said lines, and means operative thereafter for releasing the first one of said called lines from said connection.

16. In an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange to one of said lines by means of one of said incoming connectors, means whereby the called subscriber can operate his line switch and one of said local connectors to connect with the incoming connector in use `in order to transfer the call, and means for giving a signal to the called subscriber to notify him when the incoming connector is connected with.

17. l:[n an automatic branch exchange, subscribers lines and individual line switches therefor, incoming and local connectors for use in establishing main to branch and local connections, respectively, means for completing a call from the main exchange to one of said lines by means of one of said incoming connectors, means whereby the Y called subscriber can operate his line switch and one of said local connectors to connect with the incoming connector in use in order to transfer the call', means whereby the called subscriber can reoperate the incoming connector to accomplish the transfer, and means for giving the called subscriber an audible signal to notify him when the said connector is ready to be reoperated.

18. ln a telephone system, a telephone line having an individual line switch, a cut-olf relay for said switch, a connector switch for connecting with 'said line, a private wiper in said connector and a circuit established thereover for energizing said cut-olf relay and means controlled by a single actuation of the switch-hook at the station on said line for opening said circuit momentarily to deenergize said relay while maintaining said connector in connection with said line.

19. ln a telephone system, a telephone line having an individual line switch, a cut-olf relay for said switch, a connector switch for connecting with said line, a private wiper in said connector and lracircuit established thereover for energizing said cut-off relay, means controlled by the switch-hook at the station on said line for opening said circuit momentarily to deenergize said relay while maintaining said connector in operative relation with said line, other connector switches accessible to said line switch, said line switch being responsive to the deenergization of its cut-ofi' relay to connect with an idle one of said other connectors, and means for operating such connector to connect the said line with said first connector over a new path.

20. In a telephone system, automatic switches, means whereby calling subscribers can control said switches as connector switches to connect with desired-called lines, and means whereby called subscribers can control said switches as finder switches to connect with predetermined trunk lines.

2l. In a telephoneA system, automatic switches, means for directively controlling said switches from calling stations to connect n with desired called stations, means for initiating the operation of one of said switches from a called station, and means foroperating the started switch as a finder switch independent of directive substation control to connect with a predetermined trunk line.

22. In an automatic branch exchange, a group of trunk lines connecting with a main exchange, directively controlled local connectors for use in setting up connections between lines in the branch exchange, and means responsive to the removal of the receiver at a local station for operating one of said connectors automatically to connect with one of said trunk lines.

23. In an automatic branch exchange, a group of trunk lines connectingwith a main exchange, local connectors for use in setting up connections between lines in the branch exchange, means whereby a calling local sub scriber can directively control one of said connectors to select said group of trunk lines, the connector operating automatically thereafter to connect with the first idle trunk line, and

. means whereby a local subscriber who has been called over one of said trunk lines can l,operate one of said connectors as a finder switch to connect with the particular trunk over which such subscriber has been called.

24. In an automatic branch exchange, a group of trunk lines connecting with a main exchange, local connectors for use in setting' up connections between lines in the branch exchange, said connectors having primary and secondary movement, means whereby a calling local subscriber can cause a directive primary and automatic secondary movement of one of said connectors to connect with an idle one of said trunk lines, and means whereby a called local subscriber can cause automatic primary and secondary movements of one of said connectors to connect with a predetermined one of said trunk lines.

25. In a telephone system, two automatic exchanges and an interconnecting trunk line including a repeater, and means in one exchan e for operating said repeater to ,repeat switci controlling impulses to automatic switches in either exchange. A

accessible thereto, a subscribers line having a lineswitch individual thereto, means in said lineswitch controlled by said associated line for automatically connecting said line with said connector regardless of whether said line is initially calling or engaged in a call as a called line, and means in said connector responsive to the seizure by said line when said line is engaged in a call for automatically selecting a trunk line.

28. In a telephone system, a connector switch, subscribers lines and trunk lines accessible thereto, a subscribers line having a lineswitch individual thereto, means in said lineswitch controlled by said associated line for automatically connectin said line with said connector regardless w ether said line is initially calling or engaged in a call as a called line, means in said connector operated when said connector is seized by said line when said line is initally calling for extending the call to a desired subscribers line under directive control of said calling line, and means in said connector responsive to the seizure of said line when engaged in a call for automaticall selecting a trunk line.

29. In a telephone system, an established connection between a calling and a called line including a trains of switches and a trunk line, connector' switches having access to subscribers lines and to said trunk line, a lineswitch individual to said called line, means in said lineswitch controlled from said called line for actuating said switch to seize one of said connectors, and means in said connector responsive to the seizure for automatically establishing connection with said trunk line.

Inl witness whereof, I hereunto subscribe my name this 30th da of June, A. D. 1921.- RODNE G. RICHARDSON.

In witness whereof, I hereunto subscribe my name this 30th day of June, A. D. 1921..

JOHN E. GARDNER.

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