US1627930A - richardson - Google Patents

Description

May 10 1927.

. 1,627,930 I R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Original Filed May 26. 1920 2 Sheets-Sheet 1 f fiudns rflglglardsu fin-2% May 10 1927.

- R. G. RICHARDSON AUTOMATIC TELEPHONE SYSTEM Inuen DI" I Rodney fl fi L lfrcfsun Ori Fi led May 26.

. confhictors.

Patented ill, lQZT/i l nen err.

RODNEY G. RICHARDSGN, OF CHICAGO, ILLINGIQ, ..A$SIGI-IOR, BY MESNE ASSIGNMENTS, TO AUTOMATIC ELECll-lli) INC, 015 CHICAGQ, ILLINGIS, A CQRPORATIDN 0F DELIL WARE AUTOMATICC TELEPHONE SYSTEM.

Application filed May 26, 1920, Serial No. 38%,353. Renewed July 21, 1926.

My invention relates in general to automatic telephone,systems, but more particularly to such systems as comprise main and branch exchanges which are intercmmected by trunk lines, the branch. exchanges being of the type at present used in large numbers to supply telephone scr ice to nianu'tactnn ing astablishments, department stores, and the like; and the nfincipal object 01? the in vention is to provide a new and improved arrangement whereby main to brunch er;- chan e calls may be transferred anioniath caily from one stetion to another at a branch exchange while the calling main exchange subscriber waits on the line.

A nui'nber or systems having the general c1 .aracterifnic described above have been designial hetore this, and have become more or lees wid ly known in the art under the name of transfer call or passing call ems. "lhese prior systems. however. have been rather complicated, and on this ziciizonnt have been expensive to instalh and are subject to HUHJQIOUS troubles in praclice and have not, therefore gone into as ez-ztci'niled a i niblic use as might otherwise have been the case. in particular the oil cnits used heretofore involve such a radical e over. the oi 'inary switch circuits pructicuhy inn ossible to modify orix 'ete automatic excha; 'e to e trai t bout cntirclv rebiaiding the vswitches which often renders the adoption 0: such circuits oi doni' ediency A )roved {v "*il'l (ilSClOSPll herein, th nicoiiiingz. connectors which are the ice in which the main to branch trunks terminate at the latter point, which have access to the branch er:- e lines. may be of any approved or depe, and require practically no H105lior change. Calle are transferred in instance through the medium of the connectors. one of which is taken for any called party who de:-;ires to transall. end the control oi such local connector heir texercised throne! the ntiedium oi a special two way repeater associated w th the incon'iing connector in use and connected thereto by mii' ium number of Ti ere t er cell. may be transierrcd as other desired, the incom ng;

connector and the same or any other idle local connector being operated alternately. Entirely new circuit arrangements are required in order to permit the use of the local connectors in transferring calls, including among other things a special arraugen'ient whereby directive impulses may be transmitted back from a local connector by rapidly reversing the direction oi? current how in the trunk line; and in view of these facts, while the main object of the invention is, as stated the production of a new and improved transfer call system, this being the specific en'ibodiment of the invention shown herein, it is conceived that certain features of the invention will be found to be of value for other purposes and in other systems, and these features therefore are not to be restricted to the specific uses hereinafter described.

Referring now to the drawings, comprising Figs. 1 and 2, l have shown therein by means or the usual circuit d awings sutiicient of the equipment in a private automatic exchange to illustrate the invention.

In Fig. l the reference character 1) inucates an incoming connector which, as stated, may be of any approved or desired type. although it is here shown in simple form in order not to complicate the explanetion. This connector the terminal ot the main to branch exchange trunk line c'orn prising conductors l2 and 13 and const I r tes the means whereby such trunk line may be connected with any local line in the branch exchange. Associated with the incoming connector D is a group of relays indicated by reference character E. This group of relays is one 01 the special repeaters pre viously referred to and is used in transferring calls initially completed by means of (ill through the medium of individual rotary line switches two of which, the line switches individual to stations A and A", are shown and are indicated by reference characters C and C The line switch C is a similar line switch which is assigned to the repeater E, and which is provided for the purpose of giving a called subscriber access by way of the said repeater to the local connectors. Any vacant line switch may be used for this purpose, and usually there will be suiiicient extra line switches available, although if they are all in use some additional ones will have to be provided.

Having described in general terms the scope of the invention and the character of apparatus involved I will now explain more in detail the operation of the circuits, which can best be done by explaining the process of blishing a main to branch exchange connection and the process of t1-ans.cri'i11g and retrans'lin'ring such connection to various local stations. it will be assumed that substation A is the station to which the connection is to be extended in the first instance. The main exchange may be of any modern two wire type and the main to branch eX- change trunk lines may be taken off from some second or third selector level, repeaters being used in the trunks as is customary. The calling main exchange subscriber, then, may obtain access through the medium of his individual line switch and two or more selector switches to an idle trunk line extending to the branch exchange. The line switch is of course operated automatically when the receiver is removed while the selector switches are directively controlled b calling the proper digits on the calling cevice at the calling station. When the trunk to the branch exchange is connected with, the line and release relays in the repeater pull up and the latter relay closes a holdin circuit in the usual manner to maintain tie main office switches in operated position. At the same time, a bridge is closed across the two conductors of the trunk line on the outgoing side of the repeater. Assuming that the trunk line comprising conductors 12 and 13 is the one connected with, the closure of this bridge completes a circuit for the line relay 14 of the incoming connector D, which relay, upon energizing, closes a circuit for the slow acting release relay 15. The latter relay, upon energizing, prepares the connector for operation in its vertical movement.

The subscriber in the main exchange may now call the two lastdigits in the desired number, these last two digits being the digits in the local number of substation A. When the dial is operated a series of interruptions is produced in the circuit of the line relay of the main exchange repeater, which the said line relay repeats into the circuit of the line relay 14 of the connector D by producing alike series of interruptions in the bridge across trunk conductors 12 and 13. Line relay 14 is accordingly deenergized a plurality of times and at each d-eenergization transmits a current impulse to the vertical magnet 21 over the following circuit: ground at G armature 24 and its resting contact, armature 25 and its working con tact, oif normal springs 43 and 41, winding of the slow acting series relay 16, and the winding of the vertical magnet 21 to battery. The above is the circuit over which the first impulse is transmitted. Atthe first upward movement of the shaft the oil normal springs are shifted and the circuit is completed over a new path as follows: armature 25 and its working contact, off normal springs and 42, armature 27 and its working contact (rclay 16 being now energized), winding of relay 16, and the winding of the vertical magnet 21 to battery. By the operation of the vertical magnet the wipers (SO-{32, inclusive, are raised step by step until they stand opposite the .level of bank contacts in which are located the contacts associated with the line of substation A. The slow acting relay 16, which is energized in series with the vertical magnet, maintains its armature attracted during the vertical operation of the switch,

and at the end of the vertical movement deenergizes and transfers the operating circuit from the vertical magnet 21 to the rotary magnet 22.

The calling subscriber may now operate his calling device in accordance with the final digit. As before, a series of interruptions is produced at the repeater in the bridge across the trunk conductors 12 and 13, and the line relay 14 is again deenergized a number of times, transmitting impulses to the rotary magnet 22 over the following circuit: ground at G armature 24 and its resting contact, armature 25 and its working contact, off normal springs 43 and 42, armature 27 and its resting contact, resting contact of armature 32 and the said armature, armature 38 and its rest-ing contact, and the winding of the rotary magnet 22 to battery. Responsive to these impulses the rotary magnet is operated to rotate the switch wipers into engagement with the particular set of bank contacts which is associated with the line of substation A, being the bank contacts indicated in the drawing by reference characters 63-65. inclusive. T he slo acting relay 19 is ener ed in parallel with the rotary magnet and remains in operated position during the rotation of the switch. At its armature 3-1 relay 19 connects the test wiper 61 with the testrelay 18, and at its armature 35 relay 19 closes the operating circuit over path which is independent of the arn'iature 32 controlled by the test relay 18 in order to guard .inst the possibility of the latter relay being momentarily neemao energized while the test. wiper 61 is passing over busy test contacts. Assuming first that the line of substation A is busy when called above described, when the test wiper 61 com-s to rest in engagement with test contact (it, it will find a ground potential there on and the test relay 18 will be energized. hen the slow acting relay 19 deenergizes an instant later, a locking circuit will be established for relay 18 as "follows: ground at 3: armature 26 and its working contact, conductor 51, armature 134 and its resting contact, conductor 52, armature 31 and its working contact, contact springs controlled by armature 34-, and the winding of relay 1.8

to battery. In energized position the test relay opens the rotary magnet circuit at its armati'ufe 32 and at its armature 33 connects a lead tromthe busy signalling niarhine (.1. to the lower talking conductor. By this latter operation the calling subscriber is given an audible busy signal, and being ad'vizcd thereby that the desired branch exchange line is tor-the time being inaccessibio, he will replace his receiver.

Having described the operations which take place when the called line is busy, it.

now be assmned that the called line is Ui'ider these circumstances, when the wiper e1 comes to rest in engagement 1) test contact (34:, it will find no ground E111 and the test relay 18 will not be will idle.

one: red. Then when the slow acting relay 1-9 (eenergizes the following circuit will be completco: ground at G armature 26 and its right wmlrng contact, armature (36 and. its resting co..tact, upper winding of the switaih ng relay :20, resting contact of armature 1 1 and the said, armature, test wiper 61, contact 6 winding ot' the swhchiug relay '33 of line switch C, and the winding ot the stepping n'iagnet i to battery. Upon the closure of the above circuit relays 2O l 7 3 are energized in series and the latter l :'.y-' operates to disconnect the line of substation A from its normal battery and ground connections in the line switch C. it is noted. that the relay 73 operated only about halt way, due to the tact that the line relay ot the lil" e switch has not been energizecb and the line conductors are not con nected through to the line switch wipers. A! the connector D when the switching relay 0 energized it establishes a locking circuit for itself at. its armature 89, opens the rot ry magnet circuit at its armature 38, connects ground G to the test. wiper 61 at its armature 3?, and at its arnuitures 36 and closes the talking conductors through to the line wipers of the connector.

The connection having been finally completed, ringing current from the generator Gen is projected intermittently out over the line oi" substation A in the usual manner to operate the bridged ringer at the substation. it will be noticed that the return path tor the ringing current includes the upper winding of the ring cut-oil relay 1?; il hcn the called subscriber responds by removing his receiver the ring cut-oft relay is energizet and establishes a locking circuit for itself at its armature 29. The ring cut-oil relay also opens the ringing circuit its aru'iatuiies 28 and 30, and at the working contacts of? these same armaturcs finally com- I J energizing closes a circuit Relays 101 and 1052 remain ing relay 102. energized throughout the conversation, 3 without ctl'ect unless the call t be transierred.

The complete talking connection between the calling substation in the main e2; iange and the substation it in the branch e2:-

change has now been established and the,

calling and called subscribers can converse as desired. o will now assume that for some reason or other it becomes desirable to transfer the call to another local sul'istation in the branch exchange, for eXan'ipl-e, substation A Fig. 2. The transfer is accoin plished by the called subscriber at substation A who tells the calling mainexchange subscriber to wait a moment and then operates his calling device in accordance with the digits in the telephone number of substation A the digit 1 being prefixed t the number. The operations which take place in transterring the call will now be explained. When the calling device at substation 1 opera ed for the digit 1 the back bridge relay 101 in the repeater his dceuergiacd i'i'ion'ientarily and at its armature 11s closes a circuit for relay 103. Upon energizing, relay 103 closes av loc. circuit for i c at its armaturelQO; prepares a circuit for relay at its arn'iature 101., and at its armature 119 prepares a bridge across the heavy outgoing talking conductors 1 11 and 1 12 of the repeater which is closed by the back bridge relay 1.01 when it pulls up utter the momentary deenergization. This bridge may be traced as follows: conductor 1&1, armature 112 and its working contact, armature 119 and its working contact, winding 0? polarized relay 106, and winding of impedance coil 1&0 to conductor 142.

The conductors 1%11 and extend to and terminate in the rotary line switch C and it ill) will be obvious that the closure of the bridge across these conductors will complete a circuit tor the line relay 151 of the line switch. Upon el'iergizing, the line relay completes a circuit extending through the switching relay 150 and the stepping magnet 152 in series at its armature 157, and at its armature 156 connects the test wiper 161 to the above circuit at point midway between the switching relay and the said stepping magnet. The operation now depends upon whether the test contact with which the test wiper 161 is in engagement is busy or is not busy. it this test contact is busy it will have a ground potential upon it, the switching relay 150 will be short circuited, and the stepping magnet 152, which interrupts its own circuit, will operate as a buzzer to advance the switch wipers 160162, inclusive, step by step in search of a trunk line extending to an idle local connector. This operation will continue as long as the test wiper 161 engages grounded or busy test contacts. However, we may assume that in the present case the connector H is idle when the operation of the line switch is initiated and the test contact 16 4. therefore is not grounded. Under these circumstances, when the line relay 151 is energized, the switching relay 150 is energized immediately afterwards, with the result that the trunk conductors 1 11 and 142 are disconnected from the winding of the line relay 151 and from the winding of the impedance coil 159, and are extended by means of armatures 153 and 155. wipers 160 and 162, bank contacts 163 and 165, and conductors 166 and 168 to the upper and lower windings of the line relay 214: of the local connector H, Fig. 2.

In'imediately upon the extension of the closed trunk circuit as above described the line relay 21 1 will be energized and will close the circuit of the slow acting release relay 215. Upon energizing, relay 215 prepares the circuit ot the connector for the vertical operation in the usual manner, and at armature 226 completes a holding circuit extending back to the line switch C over the following path: ground at G working contact of armature 226 and the said armature, conductor 167, test contact 16 1, test wiper 161, armature 154C and its working contact, winding of the switching relay 150 and the winding of the stepping magnet 152 to battery. It is understood that the above holding circuit is established before the slow acting line relay 151 has had time to deenergize. The holding circuit also serves to maintain a ground potential on test contact 1641 and its multiples in order to make the connector H busy.

Having called the digit 1 with the result that the outgoing trunk from the repeater E has been extended by means of line switch C to the local connector H, the subscriber at substation i may now finish the operation by calling the two digits which compose the local number of substation A. At each operation oi the calling device the back bridge relay 101 is deenergized a plurality of times in accordance with the digit called, and at its arn'iature 112 produces a series 01' interruptions in the bridge across conductors 1 11 and 14-2, thereby causing a like series of deenergizations of the line relay 214 01 the local connector H. At the same time relay 101 sends av series of impulses through the winding of the slow acting relay 100, which relay '5; energized at the lirst impulse and remains in operated position during the series of impulses. At its armature 111 relay 101) opens the lower heavy talking conductor at the repeater and closes the bridge across conductors M1 and 142 over a direct path which extends from conductor 1 11 by way of arn'iature 112 and its working contact, working contact of armature 116 and the said armature, and the working contact of armature 111 and the said armature to conductor 1 12. These circuit changes produced by relay are the usual provisions adopted to obtain a more etficient control circuit for the local connector. Relay 100 also connects resistance 14 1 across the conductor-s 12 and 13 ot the incoming trunk line from the main exchange. This is done in order to prevent any disagreeable sound in the receiver at the calling main exchange telephone while the called party at the branch exchange is operating his dial. The shunting effect of the resistance eii'ectually prevents this, and at the same time permits the main exchange subscriber to hear what is taking place.

To proceed with the explanation, the interruptions in the bridge across conductors 141 and 1 12 produced by the back bridge relay 101 cause-dcenergizations of the. line relay 214.- of the local connector H, as stated, and the local connector is operated responsive to the calling of the two digits in the local number of substation A to establish connection with the line extending to such substation. In view of the fact that the local connector is substantially like the incoming con nector D, whose operation has already been described, it will be unnecessary to repeat the explanation in detail; but it will suiiice to say that the line relay 214 responds to the calling of the first digit to transmit a series of impulses through the slow acting relay 216 and the vertical magnet 221 in series, the vertical magnet being operated to raise the switch shaft step by step until the wipers 260-262, inclusive, stand opposite the desired level of bank contacts. The slow acting relay 216 then deenergizes and transters the operating circuit to the rotary magnet 222; and when the next and final digit is called the rotary magnet is operated to tion A".

rotate the wipers into engagement with the particular set of bank contacts in which the line of substation A terminates, these bank contacts c-eing indicated in the drawing by reference characters 2%, 26a, and 265. The slow acting relay 219' is energized in parallel with the rotary magnet and maintains its aru'lature attracted during the rotary movement. hen the test wiper 261 comes to rest in engagen'ientwith the test contact 26% it the called line is busy the test wiper will find a ground potential on said test contact and the test relay 218 will be energized, establishing a locking circuit for itself when the slow acting relay 219 falls back. The test relay 218 connects a lead from the busy signalling machine Q to the lower heavy talking conductor and thereby transmits the usual audible signal to both subscribers to advise them that the line of substation A is busy.

While the busy signal can be heard by both parties it does not prevent them from talking together and we will assume now that the subscriber at substation A will ask the main excl'iange subscriber to wait a little longer while he tries the number again. The connector H is released from the busy line by hanging up the receiver at substation A. This operation causes the back bridge relay 101 to deenergize and open the bridge across coiiductors 1 11 and 1 12, thereby permitting the line relay 214 and the slow acting release relay 215' at the connector H to deenergize. The deenergization of these two relays closes the circuit of release magnet 223 and the connector H is restored in the usual manner. Line switch C is also restored by the breaking of its holding circuit at armature 226 of relay 215. At the repeater E the deenergization of relay 101 is followed by the deenei'gization of slow wxtlng relay 102, and the latter relay breaks the locking circuit of relay 103 at arma ture 115.

The receiver is hung up only for an instant and when removed relays 101 and 102 are again energized. Since relay 103 has dc energized, ho wever, nothing further happens until the subscriber at substation A begins to call again. The same number or any other number may of course be called now, but for convenience it will be assumed that the number of substation A is tried over VJ hen the calling device isop'erated in ac cordance with the digit 1 the relay 103 is locked up, the bridge is closed across trunk conductors 141 and 1A2, and the line switch C is again operated, Assuming that the connector H is selected as before, this connector may now he reoperated to again establish connection with the'linc of substa- This time, it we assume that the line is idle, when the test wiper 261 comes to rest in engagement with. test Contact 264 it.

will find no ground potential and the test relay 218 will not be energized. The slow acting relay 219 now dee'nergizes and closes a circuit for the switching relay 220 in series with the switching or cut-oil relay 273 of the line switch C The latter relay is operated p way to disconnect the line ot sul station A i'rorn its normal battery and ground connectionsin the line switch. Relay 220 is energized also and closes a locking circuit for itself, opens the rotary magnet circuit, grounds the test wiper, and closes the talking conductors through to the line wipers. The usual signalling circuit is now established and thebell at substation A is rung autoiinatically to notify the sub-'- scriber that he is being called.

In case no response is secured the subscriber at substation A may of course hang up and release the connection in order to try some other number, the release being accomplished the same as in the previous case where the called line was busy. In view of this fact, no further explanation need be made as to this feature, and it will be as sumed that the subscriber at substation A answers when his bell is rung. When the receiver is removed the ring cut-oil relay 217 is cnergizec'l and locked up, the ringing circuit is broken, and the talking circuit through the connector H is finally completec The transmitter at substation A is now supplied with talking battery through the windings of the back bridge relay 200 0'1 connector H, and this relay, upon energizing, reverses the direction of currentflow in the trunk coming from the repeater E. As a result, the polarized relay 106, which is included in the bridge at the repeater and which heretofore has remained inoperative, now operates its armature to close the circuit ot the line relay 107. The latter relay, upon energizing, closes the circuit of slow acting relay 108 which upon energizing in turn prepares various circuits which will be discussed later.

The calling main exchange subscriber, the branch subscriber at substation A, and the branch subscriber atsubstation A are now all connected together in a three cornered talking circuit. They may converse together if desired, or the subscriber at substation A can hang up his receiver to permit the subscriber at substation A to release the connection and call another number. However, in order to proceed with the explanation, it will be assumed that the subscriber at substation A hangs up now, leaving the main exchange subscriber and the branch subscriber at substation A to converse between then'iselves'. at substation A relays 101, 102, and 103 are deenergized as before described, but the connection to substation A is not released because the bridge across conductors 141 and When the receiver is replaced lit) 142 is not broken, this bridge having been completed over a new path by means of armature 130 of relay 108. Relay 102 ha ring deenergized, a circuit is completed for relay 1.09 as follows: ground at G armature 526 and its working contact, conductor 51, a rma' ture and its resting contact, working contact of armature 129 and the said armature, and the winding of relay 109 to battery. Upon energizing, relay 109 locks itself at armature 138, closes the bridge across the trunk at a new point at armature 135, removes ground G from conductor 52 by means of armature 13 1- (this unlocks the switching relay 20 and the ring out off relay 17 of the incoming connector D), and at armature 136 closes a circuit for the release magnet 23 of connector D as follows: ground at G, armature 11S and its resting contact, working contact of armature 136 and the said arinatures, armature and its resting contact, conductor 49, off normal springs 44-, and the winding of the release magnet 23 to battery. the operation of the release magnet 23 the connector D is restored in the usual manner.

It. will be assumed now that for some reason of other it becomes necessary to transfer the call to the third substation in the branch exchange. This may of course be any other substation but for convenience it will be assumed that the call is to be transferred back to substation A. T he retranster is accomplishedby the subscriber at substation A who operates his calling de vice in accordance with the digits in the local number of substation A, the digit 1 being prefixed to the number as in the previous case. lVhen the digit 1 is called the back bridge relay 200 is decnergized mo nientarily and momentarily reversethe direction of current flow in the trunk and in the winding of polar relay 106 in bridge thereof. The polar relay responds by momentarily interrupting the circuit of the line relay 10. which, upon deenergizing, closes a circuit for the slow acting relay 105 at its armature 128. Relay 105 is accord iagly energized and prepares a circuit at its armature 126 for the slow acting relay 104: which is closed by the line relay 107 atarmaturc 12'? when it pulls up an instant later. Relay 10 1. upon energizing, brea (s the original energizing circuit of relay 105 at the resting contact of armature but immediately closes an alternative circuit for said relay at the working contact of the same armature, and we now have all three slow acting relays. relays 104, 105, and 108. energized. in parallel from the grounded armature 127 of the line relay 107. Other circuit changes produced by relay 10 1 are the following: The conductors 51 and 52 are again connected at armature 121. the release circuit opened at armature 125, an operating circuit for connecior 17 is prepared at armature 122, and a circuit for the slow acting relay 100 is prepared by means of z'n'n'iature 124..

The apparatus is now ready for the trans-- mission of operating impulse v to th corn ncctor l). lVhen the calling device at substation A? is operated in accordance with the first digit in the local number he bacl: bridge relay Q00 deenergizcd a plurality of times and produces a series of 'crsals in the currentflow in the trunk. The polar relay 106 is thereby caused to vibrate its armature and brings about a series of dcen ergizations of the line relay 10'? which at each deenergization sends an impulse to the vertical magnet 21 of the connector D over the following path: ground at arn'iature 118 and its resting contact, armature and its resting contact, armature 131 and, its working contact, armature 19.2 and its worl-: ing contact, and conductor 50 to oil normal spring 13, where it joins the previouz-ily traced operating circuit and continues through the series relay 1G and the vertical net magnet 21 to battery. The vertical ma is thus operated substantially the se...

already described to raise the switch shalt step by stop until the wipers stand opposite the proper level. of bank contacts. At he same time series of impulses is tranrunitted to the slow acting relay 100 by ill? armature 12?. and this relay accorci glv is operated and remains in ope tion I I UL- 1 while impulses are being transmitted over the main operating circuit. Relay 100 performs substantially the same functions in the present case as in the case where the call *as being transferred for the til, i tine, except that since relay 102 s deen ml 1 c a and its armature 116 is retracted position the polar relay 100 is not cut out of the bridge, out only the impedance coil 140.

The calling device at subs i ien .fi" operated in accordance with the last and as before a series of r0 duced in the current in the of i e 10 which reversals the polar relay 1 l and interrupts the circuit of the line r:la 107. The line relay now nsinits a series of impulses over the operating circuit including concuctor to the rotary magnet 22 and the wiper; of the connector D are rotated and finally brought to rest in engagement w th the burl contacts 5" ociated with the line of subs... ion A. lf tpe line s found to be busy the test relay 1?- will b energized and both r2iab'- -'cribers will he the busy signal. The transferrin who iu will be remembered is the at substation A can new release the connection and call the same or any other nuin or over again if he so desires. The release is accomplished by he in; up the receiver in the custon'iary manner, as was done under similar conditions when thecall Was being transferred in the other direction. hen the receiver is replaced the back bridge relay 200 falls back the current in the trunk line is reversed back to its normal direction of flow and the polar relay 106 opens the circuit of line relay 0?. lrhcn the latter relay decncrgizes the three slow acting relays 101-, 105 and 108 are permitted to fall back also and relay a!v disconnecs ground troin conductor as at ts arn'ic-i e l and also close the release ci lit at its armature 1235. "lhe connector l) is thereupon restored to normal position as already described. it is noted that relay 10$} remains locked up when the release takes place in order to maintain the bridge across the trunk intact The same or any other number may now be called again when the receiver is removed again at substation A the digit 1 being prefixed as before. Assuming that substation A is called again and that the line is found to be idle,- the connection will be completed and the bell will be rung in the manner already described. When the subscriber answers thering cut-oti' relay 1? will energize to cut oil the ringing generator and close the talking circuit. Theback bridge relay 101 now pulls up and closes the circuit of the slow acting relay 102. Upon energizing, relay 102 breaks the locking circuit of relay 109 and this relay falls back, restoring the circuits it controls to their original condition. 1 i I 1 p All three subscribers are new again connected in athr'ee cornered talking circuit similar to the one first described. Either party in the branch exchange may noW hang up and leave the other two parties to con verse and it the subscriber at substation A hangs up'the subscriber at substation jfiwill be free to release the connector D and call another number: However, it will be assumed that the subscriber at substation A who is the party that last transferred the call hangs up and'leaves the main exchange subscriber to converse with the subscriber at substation A". In this case the connection through the line switch C and connector H is released. When the receiver is replaced at substation A the back bridge relay 200 is deenergized, the current in the trunk is reverse'dyand the polar relay 106 breaks the circuit of linerelay 107. The line relay and slow acting relays 104i, 105. and 108 new fall back. lVhen relay 108 deenergizes, the

bridge across conductors 1 11 and 1 12 is,

broken, for relays 109 and 108 are both at normal and the connector H and line switch G are released and restored to norm-alas bel'ore explained. All theapparatus is now in the same condition as when the subscriber atsubstation A was originally c2 lled by the subscriber at the main exchange. If desired, the call can again be transferred, and in fact the transferring operations can be continued as long as necessary} the incoming connector and an idle local connector being operated alternately as explained.

When the calling subcriber in the main exchange hangs up, any connection whirl llll I have been established in the branch on changeis released, Whether established by means of the incoming connector or by 1" cans of one of the local connectors. When the switches in the main exchange are released, which isbrought about in the customary and well known manner, the bridge across the trunk conductors 12 and 13 is broken and the line relay 141 of the incoming connector D is deenergized. Aninstant later the release relay 15 will fall back and in case the connector is in operated p'osition the circuitof the release magnet 23 Will be closed and the connector Will be restored. hen relay 15 deenergizes it also removes ground from conductor 51 and in case a connection is up on one of the local connectors the locking circuit of relay 109 Will be broken (it this relay is energized) and also the circuit of relay 108 will be broken. This insures the opening of the bridge across the trunk conductors 14:1 and 1 12 and the local connector and line switch C are accordingly released.

Having described-my invention What 1 consider to be new and desire to have protected by Letters Patent Will be pointed out in the appended claims;

What I claim is:

1. In an automatic branch exchange, incoming and local connectors, means for corn pleting a call from the main exchange by means 01 one of said incoming cormectors, and means for transferring the call by means of any one of said local connectors.

2. In an automatic branch exchange, incoming and local (JOnDGCtCI'S, means for completinga call from the main exchange by means of one of said incoming connectors, and means for repeatedly tr sterrinn' the same call by means oi a plurality of said lo'cal connectors.

3. In an automatic blallcl'l exchange, incoming and local connectors, means for cornpleting a call trend the main exchange by means of one of said incoming connectors, means for operating any idle local connector to transfer the call, and means for then releasing the incoming connector Without releasing the local connector.

4:- In an automatic branch exchange, incon'iing and local connectorsnneans for completing a call'from the main exchange by means of one of said incoming;c'onnecto 4-, and means for operating any local connector and the incoini'i'i'g connector in use alternately to transfer and retran fer the call.-

l 5. In automatic branch exchange. a grou o local connectors and means for operating thein to complete local calls n-iginating in the branch exchange, a group of incoming connectors, means whereby a main exchange subscriber can operate one of said incoming connectors to establish connection with a desired local line in the branch exchange, and means whereby the called subscriber can operate one of said local connectors to transfer the call to another local line in the branch exchange.

6. In an automatic branch exchange, a group of local connectors and means for operating them to complete local calls originating in the branch exchange, a group of incoming connectors, means whereby a main exchange subscriber can operate one of said incoming connectors to establish connection with a desired local line in the branch exchange, means whereby the called subscriber can operate one of said local connectors to transfer the call to another local line in the branch exchange, and means whereby the subscriber first called can release himself from the connection without breaking the connection to the second local line.

7. In an automatic branch exchange, a group of local connectors and means for operating them to complete local calls orig inating in the branch exchange, a group of incoming connectors, means whereby a main exchange subscriber can operate one of said incon'iing connectors to establish connection with a desired local line in the branch exchange, and means for operating one of said local connectors and the said incoming connector alternately to transfer and retransfer the call.

8. In an automatic telephone system, a main exchange and a branch exchange, a group of incoming connectors at the branch exchange accessible to subscribers in the main exchange for use only in completing main to branch exchange connections, a group of local connectors at the branch exchange accessible only to subscribers in the branch exchange for use in completing local connections and also for use in transferring calls initially completed by said incoming connectors, and means whereby when any connection from the main exchange is completed the incoming connector in use and one or more local connectors can be operated alternately to transfer and retransfer the call.

9. In an automatic branch exchange, a local connector and means for operating itto complete local calls originating in the branch exchange, an incoming connector for completing main to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a desired local line in the branch exchange, means whereby the called subscriber can operate said local connector to transfer the call to another local line, and means whereby the subscriber first called can disconnect himself without releasing the transferred call.

10. In an automatic branch exchange, a local connector and means for operating it to complete local calls originating in the branch exchange, an incoming connector for completing main to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a desired local line in the branch exchange, means whereby the called subscriber can operate said local connector to transfer the call to another local line, and means for releasing the incoming connector when the subscriber first called hangs up his receiver.

11. In an automatic branch exchange, a local connector and means for operating it to complete local calls originating in the branch exchange, an incoming connector for completing main to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a. desired local line in the branch exchange, means whereby the called subscriber can operate said local connector to transfer the call to another local line, means for releasing the incoming connector when the subscriber first called hangs up his receiver, and means whereby the second called subscriber can reoperate the incoming connector to transfer the call to a third local line.

12. In an automatic branch exchange, 10- cal connectors and means for operating them to complete local calls originating in the branch exchange, an incoming connector for completing main to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a desired local line in the branch exchange, means whereby the called subscriber canoperate one of said local connectors to transfer the call to another local line, means for releasing the incoming connector when the subscriber first called hangs up his receiver, means whereby the second called subscriber can reoperate the incoming connector to transfer the call to a third local line, and means for releasing the local connector when the second called subscriber hangs up his receiver.

13. In an automatic branch exchange, local connectors and means for operating them to complete local calls originating in the branch exchange, an incoming connector for completing main to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a desired local line in the branch exchange, means whereby the called subscriber can operate one of said local connectors to transfer the call to another local line, means for releasing the incoming connector when the subscriber first called hangs up his receiver, means whereby the second line.

called subscriber canereoperate the incoming connector to'transfer the call'to a third local llne, means forreleaslng the local'connector 14. In-an automatic branch exchange, local connectors accessible only to branch exchange subscribers tor completing localcalls, an incoming connector initially accessible onlyto main exchange subscribers for completing main to'branch exchange call-s, means whereby a main exchange subscriber can operate said incoming connector'to connect with a desiredlocal line in the branchexchange, means whereby the call ed subscriber can operate one of-said local connectors to transfer the, call to another local line, and means whereby the calledsubscriber canrelease the local'connector and call again ifthe line called is busy.

15. In an automatic branch exchange, a local connector accessible only to branch exchange subscribers for completing local calls, an incoming connector initially accessible only to main exchange subscribers for completing main-to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a desired local line in the branch ex change, means whereby the called subscriber can operate one'ot said local connectors to transfer the call to another local line, and means whereby the called subscriber can re lease the local connector and call another number if no answer is obtained.

16. In an automatic .branch exchange, a local connector for completing local calls, an incoming connector for completing main to branch exchange calls, means whereby a main exchange subscriber can operate said incoming connector to connect with a desired local line in the branch exchange, means whereby the called subscriber can operate one of said local connectors to transfer the call to another local line, means for releasin g the incoming connector, means whereby the second called subscriber can reoperatc the incoming connector to'translier the call to a third local line, and means whereby the second called subscriber can release the incoming connector and call again if the line called is busy.

17. Inan automatic branch exchange, a local connector for completing local calls, an incoming connector for completing main to branch exchange calls, means whereby .a

main exchange subscriber can operate said incoming connector to connect witha desired local line in the branch exchange, means whereby the called subscriber can operate said localconnector to transfer the call to another local line, means for releasing the tors to transfer the call to incoming connector, means whereby the second called subscriber can reoperate the incoming connector to transfer the call to a third'local line, and means whereby the second called subscriber can releasethe incoming connector and call another number it no answer'is obtained.

18. In an automatic branch exchange,'loca1 connectors and means for operating them to complete local connections originating in the branch exchange, incoming connectors for completing connections from the main exchange, and means associated with each incoming connector whereby a local connector can be used to transfer a call.

19. In an automatic branch exchange, local connectors and means toroperating them. to complete local COIIHECtlOllS originating in the branch exchange, lncomlng connectors for completing connections from the mainexchange, and means associated with cachincoming connector whereby any branch subscriber called from the main exchange can operate one of said local connectors to transferthe call to another branch subscriber.

20. In a telephonesystem, a main exchange and a branch exchange, a trunk line extending from the main exchange and terminating in an incoming connector in the branch exchange, means whereby a calling main exchange subscriber can obtain access to said trunk line and operate said connector to extend a connection to a called l ne in the branch exchange, connectors in the branch exchange accessible only to branch exchange subscribers for completing local connections originating in the branch exchange, and means associated with said incoming connector whereby the subscriber on the called line can operate an idle oneot' said localconnectors to transfer the call to another called line in the branch exchange.

21. In an automatic branch exchange, local connectors for completing local con nections, incoming connectors for comp-leting connections from the main exchange, and switching mechanism comprising a repeater and a line switch associated with each incoming connector whereby any branch subscriber called from the main exchange can select and operate one of: said local conned another branch subscriber.

22. In an automatic branch exchange, local connectorsfit'or completing local connections, incoming connectors for completing connections from the main exchange, an automatictrunkingswitch individual to each incoming connector, means responsive to a single interruption of a called line circuit whereby any branch subscriber called from the main exchange can operate the trunking switch associated with the incoming connector in use to select an idle local connector, and means for then operating the se lit) lected local connector to transfer the call to another branch subscriber.

23. In an automatic branch exchange, local connectors for completing: local connections, lDCOIHlDQ: connectors for completing; connections From the main exchange, an automatic trunking); switch individual to each incoming; ((lllllPOi'Ol", means whereby any branch subscriber called from the main exchange can operate the trunking: switch associated with the incoming connector in use to select an idle local connector, means for then operating the selected local connector to transter the call to anothe branch subscriber, means tor releasing the incom ing connector in use, and means whereby the second branch subscriber can reoperate such incoming comiector to rans-tor the call to a third branch subscriber.

2-4, In a telephone system, a trunk line extending from a main exchange to a branch exchange and terminating; in an incoming connector, means for operating; said connector to complete a call from the main e1:- change, local connectors at the branch exchange, and means for establishing a branch connection from said trunk line around the incoming connector to any idle one of said local connectors. V

25. In a telephone system, a trunk line extending from a main exchange to a b anch exchange and terminating; in an incoming connector, means for operating said connector to complete a call from the main exchange, local connectors at the branch exchange, means for establishing a branch connection from said trunk line around the incoming connector to any idle one of said local connectors, and means for operating the local connector to which the branch has been extended to transfer the call.

26. In a telephone system, a trunk line extending from a main exchange to a branch exchange and terminating in an incoming connector, means for opeiwiting' said connector to complete a call from the main exchange, local connectors at the branch exchange, means tor establishing a branch connection from said trunk line around the incoming connector to any idle one of said local connectors, means tor operating the local connector to which the branch has been extended to transfer the call, means for releasing); the incoming: connector, and means whereby the party to whom the call has bee transterred can transmit directive current impulses back over said branch to reoperate said incoming connector to rctrans'l'er the call.

27. In a telephone system, a repeater and a connector permanently associated with each other, means for temporarily associating another connector with said repeater, and means in said repeater for then operatinpsaid connectors successively to connect with subscribers lines while maintaining the said other connector in association with said repeater.

28. In a telephone system, a trunk line accessible to a calling line and having two branches term nating, rwpectively, in a connector and in a repeater, means for completing the connection to a called line by means of said connector, and means for extending the connection to another called line under control of said repeater while maintaining the first established connection.

2f). In a telephone systen'i, a trunk line accessible to a calling; line and having two branches terminating, respectively, in a connector and a repeater, means For operatingsaid connector to extend the first. branch to it called line while maintaining the repeater in normal condition, another connector, and means for operating said last connector by means of said repeater to extend the second branch to another called line.

30. In a telephone system, a trunk line accessible to a calling line and having two branches terminating, respectively, in a connector and a repeater, means for operating said connector to extend the first branch directly to a called subscribers line, a plurality of other connectors having access to said called line, an automatic switch for connecting said repeater with an idle one of said other connectors, and means for operating the connector so connected through the medium of said repeater to extend the secont branch to another called subscribers line while maintaining the connection through the first connector.

3i. In a telephone system, a truul: line accessible to a, calling line and having; two branches terminating, respectively, in a connector and in a repeater, means whereby the subscriber on the calling line can control said connector to connect with 21 called line, another connector. and means whereby the subscriber on the called line can control the said other connector by means of said rcpeater to connect with another called line.

32. In a telephone system, a trunl: line accessible to a calling: line and having two branches terminating, respectively, in a conhector and in a repeater, means whereby the subscriber on the calling line can control said connector to connect with a called line, another connector, means whereby the sub scriber on the called line can control the said other connector by means ot said repeater to connect with another called line, and means whereby the subscriber on the second alled line can control the said first cor aector by means of said repeater to connect with a third called line.

In a telephone system, a trunk line accessible to a calling line and having two branches terminating, respectively, in a conlot) llll

1 ill) reafneso nector andin a repeater, means whereby the subscriber on the calling line can operate said connector" to completethe connection to a called line, another connectonaccessible toisaid repeater, andimean's for operating said connectors alternately under control 01 staidrepeater to transfer and retransfer the call.

Set. In a telephone system, a trunkil'ig connect ion terminating at opposite: ends in automatic connector switches, a repeater and a trunlc selecting switch included-in the con nection, means for initially operating one of said connectors to connect with a called subscribefis line, and: means whereby any called subscriber whose line has been connected with'by either of said connectors can operatesaid repeater to control the other of said connectors to connect with another subscribers line;

1 35,. In a telephone system, a connector and a repeater permanently tiedt'ogether, means including' said' connector forcompleting a connectionfrom a calling to a calledline, other connector 5, and means for transferring the calhto another calledline with any idle one of said'othercoiniectors andunder control of said-repeater.

36.. In a telephone system, a trunk line divided at. one end and terminating in a connector; and; a repeater, means including an automatic trunking; switch and another connector. for extending the repeater brancl'i into, connection with aca-lledline, means for transmitting impulses back. over the extended connection to the repeater, and means in said repeaterresponsiveto said impulses for controlling the saidconnector to extend means for establishing a flow 0t direc the connector branch into connection with another called line.-

3.7. In a telephone system, a trunk line, a icpeater in said trunk line adapted to: repeat impulses in either direction, fillfltlEOr inatic/ switch at each end otithe trunk. line 'responsiveto; impulses from said repeater,

number, and an automatic directivcly controlled switch operated responsive to said current reversals.

39. In a telephone system, a trunk line, an automatic connector switch forextending said'trunk line into connection with a subscribers telephone line, meansfor establishing a flow of direct current in said. trunk line, and subscriber controlled means tor repeatedly reversing the direction ofasaid Cl'l rectv current flow in saic ltrunk line to openatc-saidiconnector toestablish the connection 40. In. a telephone system, a closed line circuitincluding a source of direct current, an automatic switch, means for producing a series of reversals in the current flow in said circuit in accordance with a digit in a telephone number, and a polar relay in said circuit responsive to saidreversals for directively controlling said switch.

, In a. telephone system, a trunk line, means: for establishing flow 01 direct current ov-er thetwo sides of said trunk line in series, meansttor transmitting impulses over said trunk line by producing. momentaryreversals in the direction of current flow, and an automatic directively movable switch responsive to said impulses.

42. In a telephonesystem, a trunk line, means for establishing. a flow oiicurrentover the two sides 01 said trunk line in series, means for transmitting impulses over said trunk line in one direction by producing momentary interruptions in the circuit, meansifor transmitting impulses in the 0pposite direction by producing; momentary reversals in the direction of current flow, and automatic directively movable: switches responsive to the two kinds of impulses ,respectively. r i

43. In a' telephone system, a trunk line, means for establishing a flow of current over the twoisides of saidtrunhv line in series,

inean-s for interrupting the circuit at one end inaccordance with the digits in 2 called number, means for reversing the. direction 'ot'icurr-ent flow atthe other end'in the same way, and automatic directivelv movable switches responsive to the IIItQII'U'PtIOJAS' and reversals, respectively.

4A. In telephone system, a series of automatic switches including: final connector for completing a connect-ion between a calling and called-line, means in'said connector for feeding battery back through one or more of said switches inthe'direction ot the calling line, a reversing relay controlled the called subscriber, and another autothe said branch, and a polarized relay in said branch responsivetosuchcurrent rc' versals to operate-said first connector to connect with another subscriberslinep 7 46. In a telephone system, a trunk line Ill) tit)

having an automatic connector switch at one end, means including another connector switch for extending the other end of said trunk line into connection with a subscribers line, a relay in said second connector controlled by the called subscriber for reversing the direction 0t current flow in said trunk line, and a polarized relay responsive to such current reversals for operating said first connect-or to connect with another subscribers line.

47. In a telephone system, an automatic switch having a line relay, a trunk line and means for extending the conductors thereof to said line relay, a bridge across said trunk for energizing said relay, manna lly controlled means for producing momentary interruptions in said bridge, the said relay being responsive thereto for operating said switch to connect with a called line, and means con trolled by the called subscriber for closing a second bridge across said trunk line to prevent the release said switch in case said first bridge is permanently opened.

48. In an automatic branch exchange, agronp of local connectors for completing calls between branch subscribers, primary line switches individual to the branch exchange lines and having access to said connectors, a group of incoming connectors, means whereby a main exchange subscriber can operate one of said incoming connectors to establish connection with a desired branch subscribers line, a line switch individual to each incoming connector having access to said local connectors in common with said primary line switches, means responsive to a single momentary interruption of the called line circuit whereby the subscriber on the called line can operate the line switch associated with the incomin connector in use to connect with an idle local connector, and means whereby the called subscriber can then operate the selected local connector to extend the connection to a second called line.

49. In an automatic branch exchange, a group of local connectors for completing calls between branch subscribers, primary line switches individual to the branch exchange lines and having access to said connector a group of incoming connectors, means whereby a main exchange subscriber can operate one oft said incoming connectors to estal' ish connection with a desired branch subscribers line, a line switch individual to each incoming connector having access to said local connectors in common with said primary line switches, means whereby the subscriber on the called line can operate the line switch associated with the incoming counector in use to connect with an idle local connector, means whereby the called subscriber can then operate the selected local connector to extend the connection to a second called line, and means whereby the second called subscriber can reoperate the incoming c011- nector in use to transfer the call to a third called line.

50. in an automatic telephone system, calling and called stations, a trunk line for extending a connection from a calling station to a called station, a repeater accessible to said trunk line, numerical switches having access to called stations, means for temporarily inter-posing said repeater between two of said switches, and means for alternately operating said switches into connection with called stations.

51. In an automatic telephone system, calling and called stations, a trunk line, a repeater accessible to said trunk line, switches having access to called stations, means controlled. trom a calling station for extending a connection to a called station via said trunk line and one of said switches, and means conrolled from said called station for temporarily inter-posing said repeater between two of said switches to transfer said call to anotiier called station.

52; In an automatic telephone system, calling and called stations, a trunk line, a repeater accessible to said trunk line, automatic switches having direct access to called stations, means controlled from a calling station for extending a connection to a called station via said trunk line, and means controlled from said called station for temporarily interposing said repeater between two of said switches to transfer said call to another station.

53. In an automatic telephone system, calling and called stations, a trunk line, a repeater accessible to said trunk line and associated with a non-numerical selecting switch having movement in one direction only, automatic switches having movement in two directions and having direct access to called stations, means controlled from a calling station for extending a connection to a called station via said trunk line and one of said two-directional switches, and means controlled from said called station for routing said extension to another called station via said repeater and said non-numerical selecting switch.

54- In an automatic telephone system, calling and called stations, a trunk line, a repeater accessible to said trunk line and associated with a non-numerical selecting switch having movement in one direction only, automatic switches having movement in two directions and having direct access to called stations, means controlled from a calling station for extending a connection to a called station via said trunk line and one of said two-directional switches, and means controlled from said called station for routing said extension to another called station inst-@20 via said repeater and said non-nunierical selecting switchnnd via another one of said two directional switches.

In an automatic telephone system, an,

established connection between a calling and a called station, said Connection incl'i'idingn trunk line and a mimerical two-dimensional switchindividual tolsaidtrnnkline,"a repeater, a second numerical t wo-dimensional switch 'nm'mally -inaccessible to said trunk line, means in said repeater operable from said called. station torinterposing said repeater between said switches, and means in said repeater operable from said called station for operating said second two'-dimen- Sional switch into connection with a second called station. '56. In a telephone system, an established connection between a calling and a first calledstation,said connection including atrunk line *and a first numerical switch, a repeater, a second numerical switch normal ly inaccessible to said 'trunkline, means for interposing said "repeater between said switches, and'means for operating said second numerical switch into engagement with a secondcalledstation. I 57. In a" telephone system, I an established connection between a calling and a first called station, "said "connection including a trunkline and a first numericalswitch, a repeater, a second numerical switch normally inaccessible to said trunk line, means for interposin'g said repeater between said switchesyand means :t'or'operating said second numerical switchinto engagement with a second called station, both said means being under control of said first called station. I 58. In atelephone system, calling and called stations, a' trunk line,-a-first automatic switch normally accessible to said trunk line, means controlled from a calling station for operating said switch into engagement with a called station, a second automatic switch normally inacessible to said trunk line, and

means controlled from said called station for connecting said second automatic switch to said trunk line for the purpose otextending thecall to anothercall'ed station. 59. In a telephone system, calling and called stations, a' trunk line, a first" automatic switch normally accessible to said trunk line, means controlled from a calling station for operating saidswitch into'en'gagement with acalled station, a second automatic switch normally inaccessible to said trunk line, and meanscontrolled from said called station during a connection for making said second automatic switch accessible to said trunk line.

60. In a telephone system, calling and called stations, a trunk line, a first automatic switch normally accessible to said trunk line, means controlled from a calling crating said switches into engagement station 'for operating said switch into en gage'ment witha called station, a second auplurality of automatic switches at said second exchange, said trunk line terminating in said repeater, means for interposing said repeater between two of said automatic switches, and means in said repeater for alternately operating said switches into connection with called station's.

62.- In an automatic telephone system, calling and called stations, atrunk line for extending a connection from a callingstat-ion to a plurality of called stations, a repeater, automatic switches, said trunk line terminating in said repeatenmeans torinterposing said repeater between two of said switches, and means in said I'GPGQYCQTfOI alternately operating said switches into engagement with called stations.

63. In an automatic telephone system, calling and called stati0ns,a trunk line for extending 'aconnection from a calling'station to aplurality of called stations, a repeater, said trunk line terminating in said repeater, a first 'an'd a second automatic switch, means for interposing said repeater between'sald switches, and two repeat ng elements in said repeater for alternately opwith called stations.

64.1n a11 automatic telephone system, calling and called'stations, a trunk line for extending a connection from a calling sta tion to'a plurality of called stations, a repeater, said trunk line terminating in said repeater, a first and a second automatic switch, means for interposing said repeater between said switches, means in said repeater responsive to rapid successive current interruptions for operating said first switch, and means in said repeater responsive to successive current reversals for operating second switch.

In an. automatic telephone system, calling-andcalled stations, a trunk line for extending a connection from a calling st ation to a plurality of called stations, a re-v peater, said trunk lin'eterminating in said repeater, a first and a second automatic switch, means for interposing said'repeate'r between said switches, means in said repeater responsive to rapid successive current interruptions for operating said first switch, means in said repeater responsive to successive current reversals for operating said sec ond switch, and means for operating said means alternately to effectconnections with called stations.

66. In an automatic telephone system, calling and called stations, a trunk line for extending a connection from a calling station to a plurality of called stations, a repeater, said trunk line terminating in said repeater, a first automatic switch operable in response to successive current interruptions delivered to said repeater, a second automatic switch operable in response to successive current reversalsdelivered to said repeater, means for interposing said repeater between said switches, and means for alternately effecting the operations of said switches to establish connections with called stations.

67. In an automatic signalling system, calling and called stations, a trunk line, a repeater, automatic switches, said trunk line terminatin in said repeater, means for inter-posing said repeater between two of said switches, and means for alternately and successively operating said switches to establish temporary connections with called stations.

68. In an automatic signalling system, calling and called stations, a trunk line, a repeater, automatic switches, said trunk line terminating in said repeater, means for interposing said repeater between two of said switches, means for alternately and successively operating said switches to establish temporary connections with called stations, and means in said switches for signalling said stations.

69. In an automatic signalling system, calling and called stations, a trunk line, a repeater, automatic switches, said trunk line terminating in said repeater, means for interposing said repeater between two of said switches, and means in said repeater for alternately and successilvely operating said switches to establish temporary connections with called stations.

70. In an automatic signalling system, calling and called stations, a trunk line, a repeater, automatic switches, said trunk line terminating in said repeater, means for int-erposing said repeater between two of said switches, means in said repeater for alternately and successively operating said switches to establish temporary connections with desired called stations, and means in said switches for transmitting signals to said stations.

71. In a telephone system, a trunk line associated with a repeater, an automatic switch at each end of said trunk line, telephone stations accessible to said switches, the talking conductors of said switches being conductively separated from the talking conductors of said repeater but inductively united therewith, two repeating elements in said repeater, means for operating one of said elements by rapidly interrupting the circuit over the talking conductors of one of said switches, and means for operating the other of the said elements by rapidly reversing the current flow over the talking conductors leading to said other switch.

72. In a telephone system, a trunk line associated with a repeater, an automatic switch at each end of said trunk line, telephone stations accessible to said switches, the talking conductors of said switches be ing conductively separated from the talking conductors of said repeater but inductively united therewith, two repeating elements in said repeater, means for operating one of said elements by rapidly interrupting the circuit over the talking conductors of one of said switches, and means for operating the other of the said elements by rapidly reversing the current flow over the talking conductors leading to said other switch, the operation of said repeating elements serving to operate said switches.

73. In a telephone system, a trunk line associated with a repeater, an automatic switch at each end of said trunk line, telephone stations accessible to said switches, the talking conductors of said switches be ing conductively separated from the talking conductors of said repeater but inductively united therewith, two repeating elements in said repeater, means for operating one of said elements by rapidly interrupting the circuit over the talking conductors of one or said switches, and means for operating the other of the said elements by rapidly reversing the current flow over the talking conductors leading to said other switch, the operation of said repeating elements serving to operate said switches into engagement with telephone stations.

74. In a telephone system, a trunk line associated with a repeater, an automatic .switch at each end of said trunk line, tele phone stations accessible to said switches, the talking conductors of said switches being conductively separated from the talking conductors of said repeater but inductively united therewith, two repeating elements in said repeater, one of said elements being operable by rapid current interruptions over the talking conductors of said trunk line, and the other element being operable by rapid current reversals over the talking couductors of said trunk line, means for operating said elements, and means responsive to the operation of said elements for operating said switches.

75. In a telephone system, a trunk line associated with a repeater, an automatic switch at each end of said trunk line, telephone sta- Six tions accessible to said switches,'the talking conductors of said switches being conductively separated from the talking conductors of said repeater but inductively united therewith, two repeating elements in said repeater, one of said elements being operable by rapid current interruptions over the talking conductors off said trunk line, and the other element being operable by rapid current reversals over the talking conductors of said trunk line, means tor operating said elements, and means responsive to the operation of said elements for operating said switches intoengagement with telephone stations.

76. In a telephone system, a trunk line associated with a' repeater, automatic switches accessible to said repeater, telephone stations accessible to said switches, means for operating said repeater by rapid current interruptions oversaid trunk line, means for operating said repeater by rapid current reversals over said trunk line, said means being applied alternately under control of a telephone station, and means in said switches responsive to said means to operate said switches.

77. In a telephone system, a trunk line associatedwith a repeater, automatic switches accessible to said repeater, telephone stations accessible to said switches, means for operating said repeater by rapid current interruptions over said trunk line, means for operating said repeater by rapid current reversals over said trunk line, said means being applied alternately under control of a telephone station, and means in said switches responsive to said means to operate said switches into connection with telephone sta' tions.

7 8. In a telephone system using a trunk line terminating in a repeater, the method of transferring a call from one called station to another called station, consisting in temporarily interposing said repeater between two connectors having access to called stations. 79. In a telephone system using a trunk line terminating in a repeater, the method of connecting a calling station with a plurality of called stations, consisting in temporarily associating said repeater with a plurality of connectors having access to called stations.

80. In a telephone system using a trunk line terminating in a repeater, the method of connecting a calling station with a plurality of called stations, consisting in temporarily associating said repeater with a' plurality of connectors having access to called stations and of operating said connectors alternately into engagement with called stations.

81. In a telephone system using a trunk line having a repeater and associated with connector switches at each end having access to telephone'stations, the method of op erating said connectors into engagement with stations, consisting in alternately operating said repeater by rapid current interruptions over said trunk line and by rapid current reversals over said trunk line, respectively.

82. In a telephone system using an interollice trunk line associated with a two-way repeater, the method of repeating operating currents in one direction by sending rapid current interruptions to said repeater, and of repeating operating currents in the other direction by sending rapid current reversals to said repeater. s

83. In a telephone system. using an'interoliice trunk line associated'with a two-way repeater, the method of repeating operating currents in one direction by sending rapid current interruptions to said repeater, and of repeating operating currents in the other direction by sending rapid current reversals to said repeater, consisting in the provision of repeating elements in said repeater susceptible to said interruptions and to said current reversals, respectively.

84;. In a telephonesystem using a trunk line terminating in an automatic switch having access to called stations, the method of transferring a call to another called station, consisting in temporarily associating with said trunk line a second automatic switch which is normally not accessible thereto.

85. In a telephone system using a trunk line connecting a first exchange with a second exchange and terminating in said second exchange in an automatic switch having access to called stations, the method of transferring a call to another called station, consisting in temporarily associating with said trunk line a second automatic switch which is normally not accessible thereto but provided for calls within said second exchange.

86. In a telephone system using a trunk line terminating in an automatic switch having access to called stations, the method of extending connections to a plurality of called stations consisting in temporarily associating with said trunk line a second automatic switch which is normally not accessible thereto.

87. In a telephone system using a trunk line terminating in an automatic switch havingaccess to called stations, the method of extending connections to a plurality of called stations consisting in temporarily associating with said trunk line a second automatic switch which is normally not accessible thereto, and of alternately operating said switches into engagement with called stations.

88. In a telephone system using a trunk line connecting a first exchange with a second exchange and terminating in said second exchange in an automatic switch individualto said trunk line, the method of extending connections to a plurality of called stations, consisting in temporarily associating with said trunk line a second automatic switch which is normally not accessible thereto but provided for calls within said second exchange.

89. In a telephone system using a trunk line connecting a first exchange with a second exchange and terminating in said second exchange in an automatic switch individual to said trunk line, the method of extending connections to a plurality of called stations, consisting in temporarily associating with said (trunk line a second automatic switch which is normally not accessible thereto but provided for calls within said second exchange, and of alternately operating said switches into engagementwith called stations.

90. In a signalling system wherein is pro vided a trunk line terminating in an automatic switching device individual thereto, the method of successively transmitting; nals to a plurality of stations, consisting: in temporarily associating with said trunk line a second automatic switching device which is normally not accessible to said trunk line, and of alternately operating said devices into engagement with called stations.

Signed by me at Chicago Cook County. Illinois, this 20th day of May, 1920.

RODNEY G. RICHARDSON.

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