US1306826A

US1306826A - Assictob

Info

Publication number: US1306826A
Authority: US
Publication date: 1919-06-17
Anticipated expiration: 1936-06-17

Description

a. n; WILLIS. SEMI-AUTOMATICTELEPHONE SYSTEM. TION FILED )ULV LING- NENEWED APR. 23, 1919- MfPLlGA R n AR. W E? QM 7 mm rm? Mm W 4 mm 4%? n P o 93 w Q95 a s WM .Vb M w B. DQWILLIS. SEMLAUTOMATIC TELEPHONE'SYSIEM. APPLIQA'HON FILED l-ULY 7. I9l3- RENEWED APR. 28, H9.

Patent/ed June 11?, 1939.

2 Mznwsam 2.

nnnnn n. WILLIS, or CHICAGO," nitmois, nssieuon; To AUTOMATIC ELECTRIC COMPANY, or CHICAGO, ILLINOIS, ecoiaronnrion or. ILLINOIS. 1

SEMI-AUTOMATIC TELEPHONE naoegeee.

. specification of Letters Patent. v Pattem thgd June 1W3, 19119..

Application filed an 7, 1913, Serial in, 777,659. Renewed April as, 1919. Serial rm. 2,343.

To all whom it may concern: f

Be known that I, BERNARD D. .Wnms, a citizen of the United States of America, and resident of Chicago Cook County, Illinois, have invented certain new and useful Improvements in Semi-Automatic Telephone Systems, of which the following is a specification.

My invention relates to improvements in semi-automatic telephone systems in which automatic district exchanges are employed with a manual main exchange. In such systems, certain of the subscribers lines, instead ated to connect with the called line. It will" thus be seen that in such a connection two trunks between the district and main ofiices were employed;

It is the object of my present invention to provide means whereby the talkin tion between two subscribers of a single district office is confined entirely to apparatus- -located at this district oflice, thetrunk line extending to the main exchange or manual switchboard only being employed for talking purposes when thecalling subscriber desires to establish a connection with a subscriber whose line terminates in some other exchange.

By my' present invention a calling subscriber, upon initiating a call by removing his receiver from the hook, operates. his individual line switch to select'an idle trunk.

which has a branch extending to the manual switchboard. Upon the seizure of this trunk a signal is displayed upon the switchboard to indicate to the operator that a connection is desired. The operator then plugs in and,

conne'c- Ceiver 180, transmitter 181, hook switch .182

condenser 183 and the ringer 184.

back over the same trunk to operate automatic switches in the district ofliceand thus establish connection with the called line.

My invention will be more clearly understood by reference to the accom anying drawings, in which I have illustrate my in v connection with automatic (Fig. 1) and a called substation A (Fig. 2) a in a system embodying the principles oi my invention.

In Fig. 1 there is shown a', subscribers substation A the line conductors ofwhich terminate in the individual or line switch D. The line switch shown at D is one of ajgroup or similar line switches the plunger (not shown) of which engage a shaft and are controlled bythe. operation of the master switch shown at E in such a manner that they are, when in normal position, held directly in frontof the terminals of a trunk line leading through a group of relays F to a selector switch H. At C there is shown a manual operators cord circuit to which is added a calling device L. At ll (Fig. 2) a connector switch is shown which is one of a group of connectors to which the selector H has access. At 1) a line switch is shown which is similar. in all respects to the one shown at D. The substation A is in all respects similar to the substation shown -at A. The apparatusshown in both figures, with the exception of the cord circuit C, is located in a district or sub-exchange, while the cord circuit C is located in the main exchange.

Thesubstation A is of the usual common battery manual type, consisting of the reline and master switches disclosed in Brit- 1% ish Patent No. 26,30L of 1906, issued to c; R. W. James, being, however, of the particular type shown in British patent to '1. G.

-Martin No. M19 of 1910. As herein represented, the line switch D comprises among; ion

other details a plunger (not shown) attached to the end of a so-called plunger arm 10 which is controlled by a magnet 11. The

magnet also controls the armatures 12 and13 and is composed of t ur windings, namely, a 11a pull-down winding 14, holding or cut-ofi' winding '15, a'line winding 16 and an auxiliary winding 17. The magnet 11 is suitably mounted on a bracket '18 on which are pivoted the armatures 10, 12 and 13. The magnetic circuit of the two windings l4 and 15 is kept separate from that of the windings 16 and 17, so that the armatures at one end of the magnet are not affected by the ener- .bank of contact springs, forcing the springs 2, 4, 6 and 8 into contact with the

springs

3, 5, 7 and 9, respectively. Although only one set of springs (29) is shown, each line switch D is provided with a number of such groups, each groupforming the terminal of a. trunkline leading to a group of relays F,

which relays" are in turn connected directly to a first selector H. The relays 21 and 2-2 are bridged across the trunk line leading to the relays F in series with battery and become energized upon the operation of the line switch plunger upon the calling sub-- scriber removing the receiver from the switch hook. These relays are themeans of supplying battery current to thecalling sub.- scriber. The relav 23 is a slow-acting relay the springs of which, and the springs of the line-switching relay 24, control the circuit of the line signaling relay 25. The circuit is traced through the relay 26, the function of' wh1ch is to repeat the impulses created by the calling device springs L. A condenser 27 is inserted in one line conductor (Fig. 1). The complete operation of the group of relays F will be explainedlater.

Theselector H consists of the usual verti cal and rotarv magnets 19 and 20 for the purpose of raising'and rotating the shaft wipers 35, 36 and 37 onto an idle trunk lin'e leading to the connector l, the line relay 26, the release relay 29 (which is slow acting), private magnet 30, private relay 31, line switching relay24 and a rotary interrupter relay 32. The selector H is also provided with the usual side switch consisting oftwo side switch wipers 33 and 84. t

'The connector I is somewhat similar to that disclosed in United States Letters Pat out No. 815.176, granted March 13, 1906, to Keith, Erickson and Erickson, the circuits, however, being modified to adapt the switch for use in this particular semi-automaticsys tem. Like the selector, the connector is provided with a shaft (not shown) carrying the

wipers

38, 39 and 40, which shaft is controlled by the vertical and rotary magnets 41 and 42 through the medium of th line moaeae relays 51- and 52. The side switch, consisting of the side switch wipers 43, 44, 45 and 46, is controlled by the private magnet 47 in the usual manner. The connector is provided with a so-called back-bridge relay 48 through which the called subscriber is supplied with talking current. This relay is also the means of energizing the ringing cutoff relay and closing the circuit of the relay 76 in the cord circuit C (Fig. 1) when the called subscriber takes his receiver ofi the switch hookto answer the call. Ringing current is sup-plied to the called line by means of the ringing relay 51. current is sentback over the line to the calling subscriber by the energization of the busy relay 53. 54 and 55 represent the usual release magnet and relay, the former operating to release the connector switch in the well-known manner.

The line switch D is exactly the same as the line switch D and although the master switch for controlling the group. of line switches to which the switch D belongs is not shown, it can be of the same type. as the master switch E.

' Having given a general description of the apparatus lnvolved in my invention, 1 will now explain how a subscriber at the substation A obtains connection with a subsoriber at the substation A. We will assume that the number of the subscriber at the substation A is 220.. Upon the subscniber at the substation A taking his receiver off theswitch hook, a circuit is closed through the line winding 16' of the individual switch D from ground G through contact of the springs 57 and 58, conductor 59, through the telephone and back over the conductor 60, through contact of the springs 61 and 62 and through thewinding 16 to battery B. Upon the line winding becoming energized, the armature 12 operates to close the springs 63 and 67, thereby closing a circuit from ground G through the pulldown coil 14 and through the auxiliary winding 17 and the contact 200 to battery B and to ground G. The winding 14 energizes and attracts the plunger arm 10, together with ,the armature 13, which latter breaksthe contact of the springs 61 and 62, 57 and 58, thus opening the circuit of the line winding 16, the armature of which, how.- ever, does not fall back at this time, because the auxiliary winding 17 is still energized in series with the winding 14. Upon the plunger farm 10 being completely drawn down, the plunger of, the line switch is thrust into the bank terminals, pressing the springs 2, 4, 6 and 8 'into contact Withthe springs 3, 5, 7 and 9, respectively. By the same operation the springs 64 and 65 make contact to short-circuit the auxiliary winding 17, which allows its armature to fall ba k, opening the cir uit of the pull-down A busy tone this time they are stillopen.

winding 14. This does not take place, how-. ever, until after the hold-down coil 15 has been energized by a circuit over the release trunk 66 from ground G Upon the sprmgs 2, and 4 making contact with the springs 3 and 5, the line connection is extended to the two line relays 21 and 22'- of'the group of relays F, which thereupon energize. The relay 21, upon energizing, operates its springs to complete the circuit of the holding coil 15' from ground G through the contact ofthe springs 67, springs 7 and 6 and through the winding 15 to the battery lead 100. The relay 22, upon energizin closes a circuit through the slow acting re ay 23 traced from ground G springs 152, and relay 23 to the battery B. Upon the energization of the relay 23, a 'cir-. cuit is closed from the battery lead 100 through the springs 68, springs 69 and'70,

relay 26, conductor 91, contact of the answering jack J and through the pilot relay 25-to' ground G Upon the relay 26 energizing, the circuit of the relay 28 is closed from ground G, contact of springs 78' and through the relay 28 to the battery lead 100. The relay 28, uponenergizing, operates its armature to close the circuit ofthe slow-acting relay 29, which in turn operates its springs to prepare a circuit for the vertical and rotary magnets 20 and 19, the former through the contact 151-and the latter from ground G through the contacts 153 and 154 and through the interrupter relay 32 'to the rotary magnet These c1rcuits will be mentioned again later, as at relay 25 energizing, the circuit of the pilot lamp 74 is closed, thus displaying the'same to indicate to'the operator that a subscriber desires to make a call. 'The energization of the slow-acting relay'23 also connects an:

additional ground connection to the holding trunk 66 and the line switching relay 24 from ground G through the contact 150. No circuit is closed through the relay 24 at this time, owing to the side switch wiper 33 being in the first position at this time. The relay 23 prevents the release of the connection as 'far as it has gone should the calling subscriber operate his receiver hook up and down while the operator at the main oiiice is making the call, for this relay being slowacting does not deenergize as quickly as theline relay 21, and thus maintains the circuit of the holding winding closed.

Upon the signal 74 being displayed, the

operator inserts the plug Pinto the jack J in the usual manner, operates the listening key K and asks the calling subscriber the number of. the desired line. Upon the plug.

P being inserted into the jack .l, the circuits of the relays 76 and 191 are simultaneously closed and the lamp 74 is extinguished by.

the deinergization of the relay 25. if the Upon the' desired number, which we have assumed to be 220, is in the same semi-automatic subexchange as the calling; subscriber, the oper- 'ator operates, the calling device key K,

which cuts the relay 76 out of the circuit and cuts the calling device springs L into the circuit, and then proceeds to call in the usual manner. As soon as the key K is operated to include the calling device L in the circuit,

the relay 76 deenergizes, allowing its armature to drop back and again closing the circuit of. the lamp 174 at the contact 175. The operator then operates the calling device to open and close the springs L twice to thus send the impulses for the first digit 2 over the line to operate the first selector H. The

.circuit of the relay 26 is thus bro-ken twice,

which in turn twice breaks the circuit of the relay 28 at the contact 78. The armature of the relay 28 falls back a corresponding -number of times. The relay 29 being -slow-- acting does not deenergize during the mo mentary deenergization of the relay 2'8 and a circuit is closed twice extending from ground 6- through the private relay. 31 in series with the vertical magnet 20 and through the side switch wiper 33 to battery and thence to ground. The vertical magnet 20 operates to raise the shaft wipers 35,36

and 37 two steps, opposite the rowof contacts in which terminate the trunk lines leading to the connector 1. After the last of the vertical impulses has been delivered, the

slow-acting relay 31, in series with the vertical magnet, deenergizes, thereby breaking the circuit of the private magnet 30. The armature of the magnet falls back to release the side switch from first to second position,

to open the circuit of the relay 26 to thus balance the line and to cut the negative and positive lines through to the connector I, energizing the two line relays 51 and 52. The circuit for the latter relay extends from ground G through said coil, conductor 80,- line wiper 36, springs 81, conductor 90, through the jack and plug of the cord circuit- C and through the relay 191 to the b'attery B The circuit of the former extends from, ground G (Fig. 1) through the relay 75, calling device s rings L and the key K, through the plug and the jack J of the cord circuit, conductor 91,-springs 82, conductor 83. side switch wiper 43, springs 85 and through the line relay 51 to the batteryB. Upon the side switch wiper 34(Fig.

1) passing tolthirdeposition, ground ten-.

' 'tial from ground .G is placed on al the ftained closed the entire length of time the plug P is inserted into the jack J (Fig. 1). Therefore, saidjrelay is energized, retaining itsarmatiire and springsin operated position. Upon the-relay'51 energizing, a circuit is closed from ground G through the contact springs 93 and 92, 'contactsprings 94. of the relay 52 and through thesloW- acting releaserelay 55 to" the battery B.

When the relay 55 is once energized, it

7 forms a locking circuit for itself from ground G through the-contact 106 of its own springs 'and...through; jthe contact of' springs 94, thence through ,its' own winding to the battery 13. Upon the springs of the calling device again being opened twice momentarily, the line relay; 51%.is denergized;

a corresponding number. of timesto operate the vertical magnetin the usual manner to raise the

shaft wipers

38, 39 and 40 two steps. The slow-acting;private' relay 95 is 47 allowing the side switch to pass machine 102 to .mittently energizing the relay 51 to dlsconin series with the verticalmagnet /41- and upon the last impulse of this series being delivered, this relaydeenergizes, thereby breaking the circuit of the private ma rom first 'to second position and transferring batterycurrent from the vertical'magnet to the rotary magnet. Thecalling device is now operated for the third dig 1t 0,, transmitting ten -impulses over the line'and operating the rotary magnet 42 to rotate the

shaft wipers

38, 39 and 40 around ten steps. After the last impulse'of the series has'been delivered, the private magnet again dener .gizes and the side switch passes to third position. At this time the shaft wipers are resting on the desired contact, and upon the side switch wiper, '46 passing to third posit1on, the circuit through the bridge-cut-ofi relay 98 of the line switchcl) is closed, which energizes and presses together the springs 99, thus completing the connection 'to the substation A. 'Upon the side switch wiper 44 passing to third position, a circuit is closed from battery B through said side switch wiper, contact of the springs 101, and through therelay 51 to the interrupter ground G thereby internect the calling line from the called line at the springs. of said relay, and to place the ringing generator Macross the called line.

hook tb answerthe call; the back-bridge relay is energized in the usual manner to close 1 switch wiperj45,-through the 11%P6pWlIldil'lg .the same'more fully in this specification.

neoaeee The ringing generator M sends ringing current; over-the called subscribers line to ring the bell at the substation. -When the operator has finished cal1ing, she restores the key K- to its-normal position, thereby cut- 70.

ting out of the circuit the resistance coil 7 5 and cutting in the cord circuit relay 76. Since'tlie slde switch ,wiper 43 (Fig; 2') is inthird osition, the circuit including the relay 76 1s open at the springs 155 of the back-bridge relay 48. Therefore, the con-- tact spring 175- remains closed and the line lamp 174 remains lighted. Upon the called subscriber taking his receiver off the switch the circuit of the ringing cut-ofi relay 50. The circuit of the relay 48 extends from ground G through thecontact 106, through.

the lowerfwinding of the relay 48, contacts [107 and 108, through the called subscribers 5 telephone, contact 99, :contacts 110 and 111 of the relays 51 and 47, respectively,'-side of the relay 48 and through attery B'to groundfG. The circuit of the relay 50 exitendsufrom ground G over part of the circuit alreadytraced, through the contact and relay 50 and the side switch wiper 44 to the battery B. When once thisrelay is energized it remains locked by the springs 114 making contact. This lockin'g'circuit is to preventthe called subscribers" bell from ringing again should he hang up his receiver before the calling subscriber has re placedhis receiver. Theenergization of the back bridge relay also operates its springs [to close the circuit through'the line relay 76 in the cord circuit of the main office (Fig. 1), said circuit extending from ground G 106 throu h said relay, f'key Kf, plug P and the jackcontact 82 ofthe relay 24, conductor 83, side switch wiper 43, contact 155 and through the elay 51"to battery'B. Therefore, it .is seen that as soon as the called subscriber answers the call, the operator is notified of this fact by the lamp 174 being extinguished.

Should he called subscriberslrne be busy,

there will be a guarding ground potential 115 on the contact on which the private wiper- 40 comes to rest, retaining the private magnet in an operated position to keep the lines open at the contacts 107 and 111. The busy relay 53 is energized and the usual busy tone I from the busy machines is thrown back over the callin subscribers line. The busy circuit just re erred to iswell known in the art and it is thought unnecessary to describe To release the connection after the conversation has been completed, the called subscriber gives the operator at the main ofli'ce the disconnect signal in the following man- "per; Upon returning his receiver to the we conductor 83,.side switch wiper 43, springs anew switch hook, thcircuit ofthe back-bridge relay 48 is broken at the springs 170. This 7 6 of the cord circuit C (Fig. 1) is deenergized by the breaking of the contact springs" 155. This circuit extends from ground G through. the line relay 76,-key K, plug P..-

and the jack J, conductor 91, springs 82,

155 and through the line relay 51 of the connector to'battery'B. Upon the relay 7 6 nal is received by the operator, whereupon in the cord circuit (3 deenergizing, the lamp 174 is lighted and the usual disconnect sigtaken from the line switching relay 24, v

which deenergizes to disconnect the line conductors at the springs 82 and 81. At the same time a circuit is closedat the springs 159 of therelay 24, through the release magnet 160 and off-normal springs 161 to the battery lead 100. Upon .the' release magnet 1G0 energizing, the switch shaft 11s returned to its normal position, and as soon as it reaches its normal position it'opens the contact of the ofi'normal springs 161, thereby allowin the release magnet to deenergize.

Also w en the springs 150 of the relay 23 break contact, the circuit of the holding coil 15 of the line switch D isbroken,,wh1ch deenergizes and allows the plunger arm .10 to return to its normal position, together with. the plunger, thereby breaking the line extension at the bank springs 29. Upon the selector H thus being released, the llne relays 51 and 52 of the connector switch I are deenergized, the springs of the latter breaking their contact to openthe circuit of the release relay 55. This relay, as in the selector II, deenergizes to close the circuit of the release magnet 54,. releasing the switch in the well-known manner and-leavin the line in readiness for further use.

n the foregoing it has been explained how the operator calls back over the same trunk line over which the signal is received in order to call the subscriber called for when his line terminates in the same sub-exchange as that of the calling subscriber. If. the subscriber called for had been a subscriber of the main exchange, the connection would have been completed by the insertion of the calling plug P of the cord G into a multiple jack of the line in. the usual manner.

In a system of the character described herein there would be-suitable trunk lines,

in addition to those shown, leading from the ing the operator and for transmitting the departing main exchange to automatic switches in the sub-exchange for the purpose of establishing connection between calling subscribers of'the main exchange andcalled subscribers'of the sub-exchange. As trunks for this pur ose are known and do not form a feature 0 the present invention, itis not thought necessary'to illustrate the same herein. I It will thusbe seen that I have devised a very eflicient form of semi-automatic district 5 i system in which each trunk to which the subscribers individual switches have access has a branch leading to the operators switchboard, as" well as a branch leading to an individual selector switch in the district exchange. It will furthermore be seen that the trunk lines which are employed for ex' tending the talking connection are the same trunk lines which are employed for signalimpulses back from the operators board for the purpose of operating the automatic switches'to connect with a called subscriber; While I have ill'iis'trated and described my invention in connection with a semi-automatic system of a particular type, it wilhfof course, be understood that I do not wish to r limit myself to the articular system shown and described, but t at many other forms of automatic switches and operators cord circuits can be employed without. in any way from the spirit and intentof my invention.

'VVhat I- claim as my invention is '1. In a telephonesy'stem, a" trunk line, having two branches having a common terminal, means for extending a talking connection from said terminal over either of said "branches, an automatic switch associated 'ing two branches having a common terminal,

means for extending a talking connection from said terminal over either i of said branches, an automatic switch associated with one of said branches, said switch having contact arms-normally disconnected from said trunk, a relay normally connected with 1 said trunk, means for transmitting impulses back overthe'other branch to operate said relay, means controlled by said relay for controlling the operation of said switch, and means controlled by the operation of said switch for connecting said switch arms with said trunk and for breaking the circuit of said relay.

3. In a telephone system, a manual switchboard, an automatic switch, a trunk line havp terminal, and lines divided into groups ex- -tending from said automatic switch, sad

ing two branches having a common terminal, one of said branches leading directl to a jack in said switchboard and the 0t er said automatic switch, means for selzing said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side of said condenser, a signal at said switchboard controlled-by said relay, and'means for transmitting impulses back over said trunk from said manual switchboard to opcrate said automatic switch.

4. In a telephone system, a manual switchboard, "an automatic switch, a trunk line hav- 111g twobranches havlng a common terminal,

'one of said branches. leading directly to a jacklin said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay bridged across said trunk on one side of said condenser, a signal at said switchboard controlled by said relay, a second relay connected with said trunk on the other side of said condenser, means at said manual switchboard for intermittently energizing said second relay, and means controlled by the operation of said second relay extending a talklng connection over .either of said branches, a signal associated with said jack adapted to be displayed upon seizure of said trunk, means for rendering said sig" nal moperative when the cord circuit is con-' nected with said jack, means in said cord cir cuit for transmitting impulses back over said trunk to operate said automatic switch while said connection is extended to said common switch having motion in one plane to select roups and motion in a plane at right angles iereto to find a line in a selected group.

6. In a telephone system, a plurality of subscribers lines, a trunk line, a manual switchboard, means for extending a connection from one of said subscribers lines over another of said subscribers lines, means at said trunk to said manual board, means for extending said connection from said board to a second of said subscribers lines, automatic switches for extending a connection to said manual board for transmitting impulses back over said trunk to operate said switches, and lines divided into groups extending from said automatic switches, said switches having motion in one plane to select groups and motion in a plane at right isoaeae angles thereto to find a line in a selected group.

7. In a telephone system, a trunk line having two branches having a common terminal, means for extending a talking connection from said terminal over either of said branches, an automatic switch associated with one of said branches, a relay connected with said trunk, means for transmitting impulses back over the, other branch of said trunk to operate said relay, means controlled by the operation of said relay for operating said automatic switch, means controlled by the operation of said switch for breaking the circuit of said relay, and lines divided into groups extending from said automatic switch, said switch having motion in one plane to select groupsand motion in a plane at-right angles thereto to find a line in a selected group.

8. In a telephone system, a trunk line having two branches having a common terminal, means for extending a talking connection from said terminal over either of said branches, an automaticv switch associated with one of said branches, said switch having contact arms normally disconnected from said trunk, a relay normally connected with said trunk, means for transmitting imi pulses back over the other branch to operate said relay, means controlled by said relay' for controlling the operation of said switch, means controlled by the operation of said switch for connecting said switch arms with said trunk and for breaking the circuit of said relay, and lines divided into groups extending from said automatic switch, said switch having motion inone plane to select groups and motion in a plane at right angles thereto to find a line in a selected group.

9. -In a telephone system, a trunk line having two branches having a common terminal,

means for extending 'a talking connection 7 from said terminal over either of said branches, automatic switches associated with one of said. branches, a condenser in said trunk, arelay connected with said trunk on one side of said condenser, means for transmitting impulses back over the second branch of said trunk to operate said relay, means controlled by the operation of said relay for controlling the operation of said automaticswitches, and lines divided into groups ex I tending from said automatic switches, said switches having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a selected group.

10 'In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leadingdirectly to a jack in said switchboard and the other to said automatic switch, means for seizing said common terminal for extending a connection over either of said branches, a

assesses condenser in one side of said trunk, a relay connected with said trunk on one side of said relay to control the operation of said automatic switch, whereby a talking circuit is set up over the said common terminalthrough the medium of said manual switchboard, and lines divided into groups extending from said automatic switch,said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line ina selected group.

11. In a telephone system, a manual switchboard, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading di rectly to a jack in said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a relay brid e across said trunk on one side of said. condenser, a signal at said switchboard controlled by said relay,

means for transmitting impulses back over said trunk from said manual switchboard to operate said automatic switch, and lines divided into groups extending from'said automatic switch, said switch having motion in one planeto select groups and motion in a plane at right angles thereto to find a line in a selected group.

v12. In a telephone system, amanual switchboard, an automatm switch, a trunk line having two branches having a common terminal, one of said branches leading directly to a jack in said switchboard and the other to said automatic switch, means for seizing said common terminal, a condenser in said trunk, a'relay bridged across said trunk on one side of said condenser, a signal at said switchboard controlled by said relay, a second relay connected with said trunk on the other side of said condenser, means at said manual switchboard for intermittently energizing said second relay, means controlled by the operation of "said second relay for controlling the operation or said automatic switch, and lines divided into groups extending from said automatic switch, said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a selected group.

13. In a telephone system, a subscribers line, a plurality of trunk lines, a trunk-selecting switch adapted to make connection with an idle one of said trunks, each of said trunks having two branches, asprmg jack at the end of one of said branches, an automatic switch in which the other branch terminates,

a cord circuit associated with said spring jack having means for transmitting impulses back over one branch to operate the automatic switch associated with the other and motion in a plane at right angles thereto to find a line in a selected group.

14. In a telephone system, a subsciibers line, a plurality of trunk lines, a trunk-so lecting switch adapted to make connection with an idle one of said trunks, each of said trunks havingtwo branches, a spring jack at the end of one of said branches, an automatic switch in which the other branch terminates, a signal associated with each jack, means for displaying the corresponding sig nal when said trunk-selecting switch makes connection with one of said trunks, means associated with said selected. jack for trans mitting impulses back over one branch of the selected trunk to operate the automatic switch associated with the other branch of said trunk to extend 'a connection over said l common terminal, and lines divided into grou s extending from said automatic switc said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line, in a selected group.

15. In atelephone system, a subscribers line, a plurality of trunk lines, a trunk-selecting switch adapted to make connection with an idle one of said trunks, each of said trunks having two branches, a spring jack at the end of one of said branches, an automatic switch in which the other branch terminates, a signal associated with each jack, means for displaying the corresponding signal when said trunk-selecting switch jmakes connection with one of said trunks, a cord circuit with a plug adapted to be connected with said selected jack, means controlled by the insertion of said plug in said jack for rendering said signal inoperative, an impulse transmitter associated with said cord circuit for transmitting impulses back over one branch of said'sele'cted trunk to operate the automatic switch associated with the other branch of said trunk, and lines di- 'ided into groups extending from said automatic switch, said switch leaving-v motion in one plane to select groups and motion in 'a plane at right angles thereto to find a line in a selected roup.

branch 'operated when a cgnnection is extendedthereover.

17 L In a telephone system, a local exchange and a distant exchange, a trunk line having controlled by the 0 eration of said switch two branches, having a common terminal, means for extending a talking connection from said terminal over one of said branches to the subscribers of the local exchange and over the other branchto the subscribers of the distant exchange, automatic progressively movable switches associated with one of said.

'branches,'means for transmitting impulses back over the, other branch to operate said automatic switches, and a signa'l associated with said other branch operated when a connection is extended thereover. I

18. In a telephone system, a trunk line having two branches having a common terminal, means for extending a talking connection from said'terminal over either of said branches, anautomatic switch associated with one of said branches, a relay connected with-said trunk, means for transmittin impulses back. overthe other branch of said trunk to operate said relay, means controlled by the operation of said relay for operating said automatic switch, means for breaking the clrcuit of said relay, a signal associated with one of the branches,

and means under the control of the automatic switch in the other branch for rendering said signal inoperative over the trunk. 19. In a telephone system, a trunk line having two branches having a common terminal, means for extending a talking connection from said terminal over either of said branches, an automatic switch associated with one of said branches, said switch having contact arms normally disconnected from said-trunk, a relay normally connected with said trunk, means for transmitting im pulses back over the other branch to operate said relay,- means controlled by said relay for controlling the operation of said switch, means controlled by the operation .of said switch for connectin said switch arms with said trunk and for breaking the circuit of said relay, a signal associated with one of the branches, and means under the control of the automatic switch, in the other branch for rendering said signal inoperative over the trunk.

20. In a telephone system, an automatic switch, a trunk line having two branches having a common terminal, one of said branches leading -.to said automatic switch and the other of said branches terminating ina spring jack, an operators cord circuit adapted to be, connected with said jack, means for seizing said common terminal for extending a talking connection over either of said branches, a signal associated with the branch terminating in said jack adapted to be displayed upon seizure of .said trunk,

isoaeae means forrendering said signal inoperative when the cord circuit is connected with said jack, means in said cord circuit for transmitting' impulses back over said trunk to ,operate said automatic switch, lines divided into groups extendin from said automatic switc said switch aving motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a s elected group, and means under the control of said automatic switch in the other branch for rendering said signal inoperative over the trunk.

21. In a telephone system, a trunk line having two branches havingv a common terminal, means for extending a talking connection from said terminal over either of said branches, 'an automatic switch associated with one of said branches a relay connected with said trunk, means 'or transmittin impulses back over the other branch of sai trunk to operate said relay, means con-.

trolled by the operation of said relay for operati said automatic switch, means controll by the operation of said switch for breakingthe circuit of said relay, lines divided into roups extending from said automatic switc said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a line in a selected group, a signal associated with one of the branches, and means under the control of the automatic switch in the other branch for rendering said signal inoperative.

overthe trunk.

22. In a. telephone system, a trunkline having two branches having a common terminal, means for extending a talkincr connection from said terminal over either of said branches, an automatic switch associated with one of said branches, said switch having motion in one plane to select groups and motion in a plane at right ngles thereto to find a line in a selected group, a signal associated with one of the branches, and means under the control otfi said automatic switch in the other branch for rendering said signal inoperative over the trunk,

23. In a telephone system, a trunk. line having two branches having a common terminal, means for extending a talking connection from said terminal over either of said branches automatic switches as'ociated with one of sald branches a condenser in said trunk,

relay cohnected with said trunk on one side of said condenser, means for 'transmittin' impulses back over the second branch of sai trunk to operate said relay, means controlled by the operation of said relay for controlling the operation of said automatic switches, dines divided into groups extending from said automatic switches, said switches having motion in one plane to select, groups and motion in a plane at right angles thereto to find a line in a selected group, a signal associated with one of the branches, and means under the control of an automatic switch in the other branch'for rendering said signal inoperative over the trunk;

24. In a telephonesystem, a subscribers line, a plurality of'trunk lines, a trunk-selecting switch adapted to make connection with an idle one of said trunks, each of said trunks having two branches, a spring jack at the end of one of said branches, an automatic switch in which the other branchterminates, means associated with said spring jack for transmitting'impulses back over one branch to operate the automatic switch associated with the other branch of said trunk whereby a talking circuit is set up over the said common terminal through the medium of the manual switchboard, lines divided into groups" extendin from said automatic-switch, said switch aving motionin one plane to select groups and motion in a plane at right angles thereto to "find a line in a selected group, a signal assoat the end of one of said branches, an automatic switch in which the other branch terminates, a signal associated with .each branch terminating in a jack, meansfor displaying the corresponding signal when said trunk selecting switch makes connection with one of said trunks, means associated with said selected jack for transmitting im-' pulses back over one-branch of the selected trunk to operate the automatic switch associated with the other branch ofsaid trunk, lines divided into groups extending from said automatic switch, said switch having motion in one plane to select groups and motion in a plane at right angles thereto to find a group, and in under the control of said automatic switch in the other branch for rendering said signal inoperative over the trunk.

26. Ina telephone system, a subscrirs -matic switch in which'the other branch terminates, a signal, associated with ach branch terminatingin a jack, means for displaying the ccrresponding si al when said trunk-selecting switch ma es connection with one of said trunks, acord circuit with a plug adapted to be connected with said selected jack, means controlled by the insertion of said plug in said jack for rendering said signal inoperative, an impulse transmitter associated with said cord circuit for transmitting impulses back over one branch of'said selected trunk to o crate the automatic switch associated wit the other branch of said trunk, lines divided into groups extending from said automatic switch, said switch having motion in one 1 plane to select groups and motion in a plane at right angles thereto to find a line in a selected group, and means under the control of said automatic switch in the other branch for rendering said signal inoperative over the trunk.

27. In a telephone system, a trunk line having two branches having a common terminal, means for extending a talking con nection between two subscribers via said terminal over either of said branches, auto matic progressively movable switches associated with. one of said branches, means for transmitting impulses back over the other".

branch to operate said automatic switches, a signal associated with one of the branches, and'means under the control of an automatic switch in the other branch for rendering said signal inoperative over the trunk.

28. In a telephone system, a. local exchange and a distant exchange, a trunk line having two branches, having a common termeans under the control of an automatic switch in the other branch for rendering said signal inopprative overthe trunk.

Si ed y me. at Chicago, Cook county, Illinois, this 28th day of June, 1913.

I BERNARD D. LIS.

itnesses:

A. Anon, Gr. Wane a 1 minal, means for extending a talking con-