US1292522A - Semi-automatic telephone system. - Google Patents

Description

M. SCHWARTZ.

SEMI-AUTOMATIC TELEPHONE SYSTEM. I APPLICATION FILED NOV. H), 1913. RENEWED JUNE 15, 1918.

Patented Jan. 28, 1919.

2 SHEETS-SHEET I.

m. SCHWARTZ. SEW-AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILED NOV. [0. 1913. RENEWED JUNE 15. I918.

- '1,%92,522\ Patented Jan. 28, 1919.

2 SHEETS-SHEET 2.

' particularly :to a private branch exchange systemthat is, a system in which small UNITED STATES PATENT OFFICE.

MICHAEL scnwnnrz, or LOS niveanns, CALIFORNIA, AssIGnoR T0 Aurel/liners ELEc'rnIc COMPANY, or CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS.

SEMI-AUTOMATIC TELEPHONE SYSTEM.

- Specification of Letters Patent.

Application filed November 10, 1918, Serial No. 800,163. Renewed June 15, 1918. Serial No. 240,251

T 0 all whom it may concern Be it known that I, MICHAEL SoHwAR'rz, a citizen of the United States of America, and

resident of Los Angeles, Los Angeles' following is a specification.

My invention relates to improvements in semi-.alutomatm telephone systems, and more manual private branch exchanges are employed in connection with automatic or semiautomatic systems.

Ordinarily in such systems therelease of the connection irom moaning-subscriber of a private branch exchange'togthe main exchange is controlled by the'operator at the private branch exchange. Since in smaller exchanges the operator generally has other I duties to perform than attend to the switchboard, she does not always promptly respond to the disconnect signals, and consequently the line of the called subscriber may be tied up for a considerable time after the subscribers have signaled fora disconnection.

Connector switches which maybe released by the called subscriber have heretoforebeen devised, but they are open to certain objections. Accordingly the object of my invention is to provide means whereby the ordinary form of connector switch which is released by the calling subscribe-r can be employed in these privatebranch exchange systems, and whenso' usednre released by the called subscriber hanging-up his receiver that is, when these connector switches are employed for establishing a connection between two lines, in which connection no private branch exchange is involved, then the connector is released-in the ordinary way by the calling subscriber hanging up his receiver. When, however, a call is made through a. private branch exchange, then it is not necessary to-wait for the exchange operator to release the connection, but the connection is released immediately upon the called subscriber hanging up his receiver.

My invention will be more clearly understood by reference to the accompanying drawings, vcntion in connection with a semi autoin which I have illustrated my inmatic telephone system of a particular type. I have there indicated a private branch ex change consisting of a cord circuit of a wellknown type, with a trunk line extending to a main automatic exchange, in which automatic exchange I have indicated an automatic connector switch in which the trunk line terminates. This connector switch is adapted to make connection directly with the called su'bscribers line. As-orclinarily constructed, this connector switch has access to but one hundred subscribers, and it will, of course, be understood :that where larger exchanges are employed the ordinary method of inter osing first and second selectors between e connector witch and the trunk line extending to the private branch exchange will be employed. The manner in which these switches are interposed in the trunk line and their operation are well understood in the art, and as they form no part of my present invention, it is not thought necessary to illustrate the same.

Figures 1 and 2 represent a complete connection between a calling manual telephone M and a called automatic telephone A in said system.

The telephone M (Fig. l) is an ordinary manual telephone'comprising a receiver 2, transmitter 3, switch-hook 4, ringer 5 and condenser 63. At the central office the line of thetelephone M is equipped with the usual line relay 7, line lamp 8, cut-ofi' re- Patented Jan. 28, 1am.

with the automatic exchange extends from the jack J (Fig. l) to the connector H (Fig. 2). The drop14 is normally bridged across the trunk atthe jack'J for use when a call is extended from the main to the branch exchange. board the trunk is also provided with a slow acting neutral relay loand a polarized lJ ll At the manual switch-- An :mtemetic eniQ-"mdi11g (1e else provided, thm git. the meu'ch the operator may control switches at the automatic exchange in erder 1'0 eistuoiieh the desired cmmectim.

This; calling device may be of any desired type sue/11,, for example that shown in. British patent to S. k}, S. Dicker N0. 29,-- (551 of 1910, and is herein represented elmply by pair of impulse springs 17.

The switch C (Fig. 2) is of the general. 'ype of subscribexs individual switch shown in British patent to R. WV. James N 26. 301 ef 1,906, more eleeely resembling, how ever the particular type shown in British mtent $0 T- (at. Martin Nu L419 075 1910. his'switch is controlled in the usual H1211!- ner by a master switeh (not shown} which would, be similar to the master switch 1) which eentrols the line switch (1 of the u; Had line, Whih line switch is eimilar to the swiitclg-l Ck Y The mmtieetor H (Fig fl) isnf the gem e1": eonnectexr switch diselos (Yin Lettee Patent Ne. 815,1?6 r441 13,- 1906, to Keith, Erieksen teen, the circuits howeve'n eeing e'lodiit'ied in a. nmzmer similar t0 that sshOWn tn staid British patent to T G. Martin No. L419 0t 1910, 50 as to adapt the switch 11 amezfetien. in a system in which the cent .1 attic-e :qppa ntns controlled by imflelivered oven: the two sides of the The connector is providei shaft (not shown) marrying the -14; and 45 and is contra 'SQC by i erient magnet: 46 and the rotary meg- -17. Th2 usual] side ewteh cemgnisifig 4?, -19, and 51 is emztmiled t0 nmgnet 52 in 31 weflitmmm The-magnet the usual we Benet. (Che tine why is'eened with the iine thruugh the revere} A wings 0t :1 Lwt eilii'fl! heck-bridge relay 'mzgzh the vindir s of which the (M ti t GHQ is; proviecu with Bathing CHITHEEQJ.

U We 5G and ii? are slow :mtin Aft B there ehewn :1 ringw Qenee ringing for k he 021N041 s11. ihm: it Q there'e she. {a busy sigmzi: 5;; veerent cenipmsmgzj en indm'hon mi 58 Mar ime w nter J nutenmtiv tr I is; fiimihw t0 mmmi teephene In! (Fig. 1) with the z xi 0 veltsemtingg (1e t; me)? be the line. after Wlzieh one pm 4 preferably ene A genera flee/rip tmving been ;g. u, it H. new (zoln'xeetm'a may he, manual telephone M. :1 A phone A, and 110W said released by the hanging at the called telephene.

71m. SWitfihjllg eppe :utus lifieios 7 general Welt knewn in the em scribed in the 'ymblimfiene 1511 e t0 its ope-Mien Wm exp 01 less generr-fl mamsmz t, pen, t of the receiver fi'em 'ii'xe switch 1 s11 bstat ion M prep-ms! the talking 001162.15: the line why I circuit of the A1116 emit-0r. The 01 the plug P key K to fine and med.

m stem the.

ends by in gmmm then 121111;; t0 batten .L energizmg, discormeets the Y J I step? is previded Wit? t:e "m;g "'N'Iiflltfl (We-1; r emit extend: t winding: of the thence we): the h UUC'HHE". the subr'.

4 0 her suite of i and the seeend coil to the lun'egrrvwue B. The relay 1 a shunt meme z'ee 'mnee (33. [been vt infra itmm 52:

After lean-n1 ping into Hi we eelmm'ieu dim-01111001". me hm v" a; the same time the tt'erci-(i into n e t. thetyunk commet rate? 1W Upon proper direction to maintain the contact of springs 76 and 77 closed. while the relay 15 is short-circuited by the circuit passing through the springs 76 and 77. The r lay winding 81 (Fig. 2), upon energizing, attracts the armature-21 to close the circuit of the operating winding 89, which attracts the. plunger arm 18 to extend the connection through the bank springs to the connector H and the cut-oil armature 20 to disconnect the line relay from the line. Before the armalture 21 drops back to open the circuit of the operating winding 89 after the line winding 84 is disconnected from the line, the holding winding 86 is energized in the following manner to hold the switch in its operated position. When the connection is extended to the connector H through the springs 22 and 26 and and :29 by the operation of the switch the line relay 51 is energized by reason of the closed bridge across the trunk through the relay 16 (Fig. 1). The relay 54:. upon energizing, closes the circuit of the relay 56, which, by forcing the springs 88 into contact. completes a circuit extending from ground G through said springs and through the line switch after the winding 89 is deenergize'd.

bank springs 27 and 2.3 and the winding 86 to the battery B. The energization of this winding serves to hold the plunger arm and cutoff armature in their operated positions guarding potential is also extended from ground G at the connectorthrough the springs 88, 27 and 23 and over the conductor 90.to the connector private bank contacts 30 in the bank of each connector which has access to the trunk line. Upon the closure oi the springs 2-1 and 28 of the switch C", the master switch operates in a wellknown manner to move the pluiigers of the idle switches of the group to a position opposite the terminal of an idle trunk line. The

-' operator now operates the key K (Fig. 1)

to open the bridge across the-trunkthrough the relay 16 and substitute therefor'a bridge through the springs 17 01" .b en calling dev1ce.

She now operates said calling device for the respective digits of the number of the called substation, which will be assumed to be 20. Upon the operation of the calling device for the first digit 2. the impulse springs 17 (Fig 1) are separated twice momentarily. each time breaking the circuit of the line rclav 51 of the connector H. Therelay 56 of the connector being slow acting does not dci nergize during the momentary interruptions of its circuit by the relay 54. and consequently each time the said line relay dcenergizcs in response to said impulses. an impulse is transmitted over the circuit ex tending from gronudii" through the spring 112 and its hack conta t. spring l13 iand its front Contact. relav -7. vertical nuigncr 4:6 and the side sw tch wiper 31 to the bat-' tery lead 85. The magnet 46 operates in response to the two impulses received'over this circuit to raise the switch shaft two steps, while the slow acting relay 5'? is energized to close the circuit of the private magnet and to maintain it closed continuously until after the la impulse for the digit is transmitted. After the last impulse is transmitted, the relay 5? deenergizes and opens the circuit of the private magnet 52, which, upon deenergizing. permits the side switch to pass from first to second position in a well-known manner. The movement of the side switch wiper 51 from first to second position transfers the battery connection from the vertical magnet 46 to the rotary magnet 47. The operator now operates the calling device for the last digit 0, whereby a series of ten impulses is transmitted through the rotary magnet 4:7 in series with the relay 57, whereby the shaft wipers are rotated onto the contacts of the desired line. The relay 57 operates in response to the impulses for this digit to again close the circuit of the private magnet 52. W'hen the relay 57 deenergizes after the last impulse for the last digit is transmitted. the private magnet 52 denergizes also, if the called line is idle, and per mits the side switch to advance from second to third position, whereby. through the medium of the side switch wipers 1-8 and 49. the connection is completed through the shaft wipers 43 and 44 to the called line. The side i switch wiper 50, upon passing to third position, provides a guarding potential for the connector private bank contacts of the called line and energizes the cut-off windingll-t of the switch C to disconnect said switch from the line and close the contact 115 in the talking circuit. The side switch wiper 51 of the connector, upon passing to third position. closes the circuit of the ringing relay 116 through the interrupter 117. The

relay 116 thereupon begins to operate to in- A the tall by removing his receiver. the called substation is provided with talking current over the circuit extending from ground G at the connector through the back-bridge relay 5:"). contact of Splllllls 118 of the privatc magnet 52. thence over the heavy conductors to and through the substatioi-i A and back over the otlu-r side of the line,

. I s to again com ch01;

anti? aft reaches its estm' amnion m :5 switch mu the relax.

cmmu I u (11: r

zmreiease md its brusk com act 1 is inim'rzmted at Th1 var, when gne "Quitv nit hen. the S11 raw;

tt'ery lead.

izing, (-4 i112 com'icctor switch to its; normal p0- fxs awn sir nowe, I}

ed cont (m spm ng 113 'na'ft-con'troll 1). e cross the tr G thr unmet,

13 to the b i act posihnn 11 0mm? wmchn m- .pmn't 1; fin: and

This

9 will cause the line d a a-ngement for 1 If the J before us reumvsr,

the same ned by the Idem that 110 111 nnmtm; 1)

same manner 'Was'; ()blll'ififfid *mth. the ,5

leciim H, passing cwer hers de- .aViSG mags up hlixp 10, Wilma the plugs P ackx m gize and rees 111 s ope 1:; systmn. may sysfiu (1 mm" may than 120 trunk and any the operator :1 9b

"xchangaa to the used as well for :11 SWlilfihhOflld nt drop 14: (Fi 'li'n'nngh 121m '0, "iahe'opwrz subs hm? deiinergjlzes and 1'0- give when (1 f1 15 rm'wsved from he ed subscrliimr wanking of the i the (30111 CA to ,the

sari

the

mpon m the 3 idge across the trunk 0 d (3 tm to define! :wiltch unk ed before, the trunk .2113

a the n' :16 \he aut- (f mid the L in thc b QUITE L around hangs up may tum m) and k n 111a 'X m ing (1 mam] seen that I have (k M 0 ml, m0;

non Hmh.

5. been man 13., calls 1" [I opp hushe the 211 1 oumt p ch in .1

nutonmti s (161141 Jew mmmc:

Q I l 15 trol of the calledsubscriber, which control is independent of any action on the part of the operator at the private branch exchange. Thus it will be seen that the connection will be released either by the operator taking down the connection, or, 'if she should neg- While Ihave illustrated and described my invention. in connection with automatic apparatus of a particular type, it will, of course, be understood that my invention is not limited to such use, but that it is adapted for use in connection with other forms of automatic apparatus.

What I claim as my invention is 1. In a telephone system, a plurality'ot subscribers lines.,an automatic switch for establishing connection with one of said lines. a trunk for extending a connection to said switch, inductive means separating the calling side of th trunk from the called line. and means in the calling side of said trunk controlled by the called subscriber-for releasing said switch. y

2. In a telephone system, ,Zt- 1)l1l1'2Illt of subscribers lines. an automatic switch "for, establishing connection with one of sa d lines. means including a trunk for extending a connection to said switch, inductive means separating the calling side of the trunk from the called line. a bridge across the calling side of-said trunk. and means controlled by the called subscriber for controlling said bridge to release said switch.

3. In a telephone system, a plurality of subscribers lines. an automatic switch for establishing connection with one of said lines, means including a trunk for extending a connection to said switch, inductive means separating the calling side of the trunk from the called line. a bridge across the calling side of said'trunk, and means controlled bythccalled subs riber hanging up his reccivcr for controlling said bridge to release said switch.

4. In a telephone system, a plurality of subscribcrs lines, an automatic switch for establishing connection with one of said lines, means including a trunk for extending a connection to said switch, means controlled by the called subscriber for reversing the current in said trunk, and meansin said trunk responsive to said reversal of current for controlling the release of said switch.

In atclephone system, a plurality of subscribers lines, a, connector switch for esrablishing connection with one of said lines, means including a trunk line for extending a connection to said'switch. inductive means separating the calling side of the trunk from the called line, a bridge across the calling side of said trunk, means controlled by the caliedsu bscriber for opening said bridge, and means controlled by the opening of said bridge to release said switch.

(3. In a telephone system, a plurality of subscribers lines. a connector switch for establishing connection with one of said lines, means including a trunk line for extending a connection to said switch, a bridge across said trunk, means controlled by the called subscriber for reversing the flow of current in said trunk, means controlled by said reversal of current for opening said bridge, and means controlled by the opening oi said bridge to release said switch.

7. In a telephone system, a plurality of subscribers lines, a connector switch for cstablishing connection with one of said lines, means including a trunk line for extending a connection to said switch, a bridge across said trunk, a baclcbriclge relay in said connector, means controlled by the called su'bscriber hanging. up his receiver for deenergi zing said baclcbridge relay, means controlled by the deenergization of said relay for opening said bridge, and means con trolled by the opening of said bridge to release said switch.

S. In a telephone system, a plurality of gizing said back-bridge relay, means con-.

trolled by the deenergization of said relay for reversing the current in said trunk, means controlled by said reversal of current for opening said bridge, and means controlled by the opening of said bridge to release said switch. v

9. In a telephone system, a plurality of subscribers lines, an automatic connector switch for establishing connection with one of said lines, means including a trunk line for extending a connection to said switch. inductive means separating the calling side of the trunk from the called line; a bridge across the calling side of said trunk, means controlled by the called subscriber for temporarily opcn-ing'said bridge, and means controlled by the opening ofsaid bridge to release said switch.

10. In a telephone system, a plurality of subscribers lines, an automatic connector switch for establishing connection with one of said lines, means including a trunk line for extending a connection to said switch, a bridge-across said trunk, means controlled by the called subscriber 'for reversing the polurizou relay acting relay lgo, moans v open said 1 1y the opening in ality 11a plied 1119s, an

1 inolud 4 r x connection Y means in said tion of said to a called e of 321 id. Hunk con snlisomlior for releashone. system, a plurality of oir'ouit adapted to one 01 mid limos, an autosivitoli, merino including a oni'onding a cm'mestion from (i swim- 1, means in said trunk i ration of said switch to a, ()fillfid lino, z calling side Eiil. line, abridge id trunk, and subscriber for Laseamid switch, plurality of circuit adapted to oi said Ii 19-5, on ontomoons il'iclnding a; g o, COI'IMQCiLlOH from ;'.,.h, moan. n mid trunk .1 operation of said switch connection. .10 :1 called line, o muollmii by the called subscriber for (jiiilfil'ii said trunk, and

" .z-yosponsivo to said refor controlling the release am, a. plurality of oiro'uis adapted 0 of said lines, an 2 -1to- 1;: l'noans including a, tomiiug' connection from v21s 11 said trunk n of vmid switch to a, sailed line, the calling sizle line, a, byido'e if ii we for. con- 1113; 83nd bridge, oml moanswnti'oilocl lw tho @Pfinlllg 01 said bridge to release ml. m'i'itflll,

imam; controlled by a; i

for opening said bridge, and means mmso trolled by the opening of mid bridge for releasing said switch.

17, In a telepholo system, a almwaiity of subscribers limos, u z-ox'rl (rim-nit adapted to he mnnovtecl with ono of, said limo, an 85 automatic oonnevtor switch, means inolucling a trunk line for extending a connection from id cord to said S\\'ll-1ll, means in said trunk. for controlling the ope m'aion said swim-i1 110 vompleto a. connection to called 9'0 line, inductive means si apornting tho calling side of the trunk from the called line, a bridge across the. nailing side of said trunk, moans controlled by the olled sulmcriloer for temporarily opening said. bridge, and means coi'itrollod by the opening of said bridge to release said SWit-(lL 18. In a telephono system, a plurality of subscribers lines, a cord circuit adapted to be. connected with onoof said linoo, an :iutrr mantis connector switch, means including a trunk line for extending a (-onnectvion from said cord to said switch, means in said trunk. for :ontrolling the operation of mid oil to complete a cormovtion to :1 mliml. line, means controlled by the called subsx .ilror for reversing the current in said trunk, means 1.9 In a tqlophone system, a pin 'alit y of subsc' l ms 1m. autonmtm switch for ostdl'iiisi iing connection with one of said lines, a trunk, 11 nonq'mmerical automatic switch for connecting said trunk with amid first switch, and means in said trunk vootrollod by the called subscriber for rco10'a.-;ing said first switch.

20. In, a fielephone system, a plurality of" 1212 subscribers lines, an aufon'mvtic Switch for establishing connection with mm of said lines, a trunk, a non-numerical. aufolnatio switch, means including said trunk and switch for extending connection to said first 12'? switch, a bridge across Enid trunk, and means controlled by the, called subscriber for controlling said bridge to relenso said firstswitch,

22. In a telephone system, a plurality of subscribers lines, an automatic switch for establishing connection with one of said lines, a trunk, a non-numerical automatic switch, means including id trunk and switch for extending count; on to said first switch, means controlled by the, called subscriber for reversing the eurrent in said trunk. and means in said trunk responsive to said reversal of currcn't. for controlling the release of said first switch.

23. In a telephone system; a plurality of subscribers lines, a connector switch for establishing connection with one of said lines, a trunk, a non-numerical automatic switch, means including said trunk and switch for extending connectionto said first switch, abridge across'said trunk. means controlled by the called subscriber for opening said bridge, and means controlled by the opening of said bridge to release said first switch. 1

24. In a telephone system, a plurality of subscribers establishing connection with one of said lines. a trunk,-a non-numerical automatic switch, means including said trunk and switch for extending connection to said first switch, a bridge across said trunk, means controlled by the called subscriber for reversing the flow of current in said trunk. means controlled by; said reversal of currentfor opening said b idge. and meaiis con trolled by the opening of said bridge to release said first switch.

25. In a telephone system, a plurality of subscribers lines, a connector switch for establishing connection with one of said lines, a trunk, a non-numerical automatic switch, 7 means including said trunk and switch for extending connection to said first switch. a bridge across said trunk. a. backbridge relay in said connector,'means controlled by the called subscriber hanging up his receiver for energizing said back-bridge relay, means controlled by the cnergizaion of said relay for opening said bridge. and means controlled by the opening of said bridge to release said first switch.

26. In a telephone. system, a plurality of subscribers lines, a connector switch for establishing connection with one of said lines. a trunk, a non-numerical automatic switch. means including said trunk and switch for extending connection to said first switch, a

bridge across said trunk, a back-bridgc relines, a connector switch for lay in said connector. means controlled by the called subscriber hanging up his receiver for energizing said back-bridge relay, means controlled by the energization of said relay for reversing the current in said trunk, means controlled by said reversal of current for opening said bridge. and. means controlled by the opening of said bridge to re lease said first switch.

27. In a telephone system. a'plurality of subscribers lines, an automatic connector switch for establishing connection with one of said lines. atrunk, a non-numerical automatic switch. means including said trunk and switch for extending connection .to said first switch, a bridge across said trunk. means controlled by the called subscriber tor temporarily opening said brie and means controlled by the opening of said bridge to release said first switch. 8

28. In a telephone system. a plurality of subscribers lines, an automatic connector switch for establishing connection with one of said lines. a trunk, a non-numerical automatic switch, means including said trunk 9 and switch for extending connection to said first switch. a bridge across said trunk. means controlled by the called subscriberfor (cm-- porarily opening said bridge, means con- I trolled by the called subscriber forreversing the current in said trunk, means controlled by said reversal of current for temporarily opening said bridge. and means controlled by the opening of said bridge. for releasing said first switch.

29. In a telephone system, a pluralityof subscribers lines, means including a connector switch for establishing connection with one of said lines. a trunk. anon-numerical automatic. switch, means including said trunk and switch for extending connect-i611 to said first switch. a bridge including a piolarizcd relay across said trunk, a. slow acting relay adapted to be included-in said bridge. means controlled-by the called subsllv scribcr for controlling said relays to monien' tarily open said bridge. and means controlled by the opening of said bridge to release said first switch.

30. In a. telephone system. a plurality of subscribers lines. a cord circuit adapted to be connected with one oi said lines. an automatic connector switch. a trunk line, a nonnumerical switch, means including said trunk line and non-numerical switch for eX- 129 tending connection from said cord to said first switch. means in said trunk for controlling the opcration of said switch to complete a connection to a called line, and means in said trunk controlled by the called subscriber for releasing said first. switch.

31. in a telephone system, a plurality of subscribers lines. a cord circuit adapted to be connected with one of said lines. an automatic connector switch, a trunk line, a non- 30 subscrilw fines, o cord dd: L be conncc vdo 1 id in; as, on a utm E'INLUC ccnmcctor switch, 2L twink n nnmcl'ic. switch, mcmiac. i fl 1112: {inc and ncnnumerica tending connection from said first swimh, means in said is; for m tloi iin'g the opcmtim'l of said sswnch to con.-.-- plate a connection to :1 called Hue, n'muns con."- troElcd by the coiled subscriber for reversing the current inoaid trunk, n; d me: Q, in said trunk responsi'vc to said rc *crszd of (311?! n; for control iing the rei'ca e. of said first: switch.

33. In a tc iephone a morality of subscribers lines, a cord circuit ndaph-zd to be, connected with one of, asdd limos, an cum matic connector switch m-trmxk line. a; nonnumcricai switch, means iz'icluding said trunk line and non-numwiczd swi ch for my tcnding; connection frcm said cord to said first switch, mcm'as inscid trunk for confroh ling hc operation of said switch to compl. a (UIIIIQCHOH to a coiled line, :1 bridgeacross snfid trunk. mcanscontrolled by the mfflcd subscriber for opening said bridge. and means controlled by the opening of said bridge to whose said firsi; switch.

34-. In a telephone sysficm, a pduzudity cf snbsc fibers lines, 1:- cord circuit, adapted. to be connected with one of said lincsyaxk aut0- matic connector switch, a trunk line, :1 m numerical switch, means inci'uding said trunk fine and non-numerica1 switch for c icndiog conncction fronmsaid cord to said firstswidch means in. said trunk for control iingthc operation of said switch to completc a connection to :1 called line, means com troliod by the coiled. subscriber for reversing thc flow of current in said trunk, means c0n-- frol'lcd by said reversal of current for ope/1' ing -snid 'b'ridge, and means controlled by, the opening of said bridge: for releziming said first switch.

353. In telephone systcs'n, l, plumiity 0;

1 1'01 waging and 11 plumlr'iky 5cm] switch, nacz'ms Including said c mews iuchn'io non-m1 mcmc: switch id cord to cmtion by said m. opening said 33 Y 9 opening of mid h d first switch.

phone systcm, a iny; and. mas iliuzi'mf'ing a hunk: lino h hzwifi g "am-tic i and U R'iUfiOYla cont. ,c we!" the two dos of said. trunk inc in for connect-- and moans unnoociaitcfi with m Hm (m KAXU In :1 c called 7' 1311c mconmmc sa'wiiidmzt; cow 1c two mdcc of mid firms called Hm, 111cc g Enid con-- 'jhom 3y atom twc umlnmgcs, meeting rsxvid cxchcngcm, a I? in ihc first (exmrgrc, ccalled c'imd cwxchangc, no autoirmd witch for mcnns in d" fimt; ox thc cidlcd H11 for re.

4:1. In a icicydmnc systcutl, n'm'miz 11 change, an automatic cziclumgc a trunk E cou'nc wing: said QKfhflUgfiS, o mm g c c i thc manna exchangc, 11 calicd Zinc in the on tomatic exchange, mcnns including mk: 1111c and :omaiiic m i-cl MOM):

nm' omdiic Kiwi-n and mc change, an automatic exchange, a trunk line connecting said exchanges, a calling line in the manual exchange, a called line in the automatic exchange, means including a cord circuit, said trunk line and an automatic -switch for connecting said lines, a bridge across said trunk line to prevent the release of said switch, means controlled by the operator for opening said bridge, and means controlled by the called subscriber for opening said bridge.

43-. In a telephone system, a manual exchange, an automatic exchange, a trunk line connecting said exchanges, a calling line in the manual exchange, a called line in the automatic exchange, means including a cord circuit, said trunk line and an automatic switch for connecting said lines, and mechanism associated with said trunk line whereby either the operator at the manual exchange or the called subscriber in the automatic exchange is enabled to restore the said called line to normal condition by releasing the connection.

44. In a telephone system, a calling and a called line, means including a trunk line and an automatic switch having vertical and rotary motion controllable over the two sides of said trunk line in series for connecting said lines, and a relay, associated with said trunk line and controllable from the called line for releasingsaid connection.

45. Ina telephone system, a calling and a called line, means including a trunk line and a plurality of automatic switches controllable over the two sides of said trunk line in series for connecting said lines, a bridge across said trunk line to' prevent said switches from releasing,.'and a relay congrollled over the called line for opening said 465i In a telephone system, two exchanges, a trunk line connecting said exchanges, a

connection.

47. In a telephone system, two exchanges, a trunk line connectlng said exchangesfa calling line in the first exchange, a called line in the second exchange, an automatic switch for completing connections'to the called line having vertical and rotary motion, means including said trunk line and said switch for connecting said lines, and a relay in the first exchange controlled over the connected called line for releasing said switch.

48. .In a telephone system, a manual exchange, an automatic exchange, a trunk line connecting said exchanges, a calling line. in the manual exchange, a called line in the automatic exchange, means including said trunk line and an automatic switch in the automatic exchange for connecting said lines, and a relay in the manual exchange controlled over the called line for releasing said switch.

49. In a telephone system, a plurality of subscribers lines, an automatic switch for establishing connection with one of said lines, a trunk line including a pair of talking conductors for extending a connection to said switch, indiictive means separating the calling side of said trunk line from the called line, a bridge across said talking conductors on the calling side of said trunk line, and means-controlled by the called suliscriber for controllingsaid bridge to release said switch.

Signed by me at Chicago, Cook county, Illinois, this 3rd day of November, 1913.

MICHAEL SCHWARTZ. Witnesses HARRY E. Hnnsnnr,

RAY SToxaLY.

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