US1038037A - Telephone system. - Google Patents

Description

ft WEBSTER, TELEPHONE SYSTEM.

APPLIATIGH FILED NGV. 27,19%A

i SHEETS-SHEET l.

muur

Fatente Sep. I0, 19m.

H. G. WEBSTER.

TELEPHONE SYSTEM.

APFMGATION HLM Novia?, 190s,

fi, G. WEBSTER.

Tmsmom SYSTEM.

APPLICATION FILED NDV. 27, 190B.

' Patented Sept. 10, 1912.

4 BHEETH-SEEBT 3.

L G. WEBSTER.

TELEPHQNE SYSTEM.

' PPLITON FILED NOV. 27, 1903. Patented Sept. 10, 1912.

4 SHEETS-SHEET onirica,

HARRY Gr. WEBSTER., @E CI--SO, LLINQIS, ASS'IGNR, BY MESNE ASSIGNMENTS, T0 KELLOGG SWTCHBOARD & SUPPLY CMPANY, A CIRPORATION F ILLINOIS.

TELEHONE SYSTEM.

Specicaton of Letters Patent.

Batentcd Sept 10, 1912.

To all 'whom it lnoo/ 1,1 cof/wem:

Be it known that l, HARRY G. Vnssfrnn, a citizen of the United States, residing in Chicago, county of Cook, `State of lllinois, have invented new and useful Improvements in Telephone Systems, of which the following is a specication.

'My invention relates to systems of a kind generally known as automatic ringing systems, the characteristic feature of which is found in the tact that ringing current applied to a called telephone line to ring the telephone bell intermittently or continuously until the called subscriber' answers, whereupon the act oi' answering serves to automatically terminate the connection "of the ringing circuit with the line at whose substation response has been made.

The object of the present invention is to secure an improved and simple structure oi the character described and is .found in certain simplified circuit arrangements forcontrolling; the current cut-oil device for which l preferably employ an` electromagnetic relay.

Referring to the drawings, l have shown in Figure l. an application of iny invention to a trunk cord-circuit adapted tor use with two-wire multiple switchboard; Fig. 2 shows an application of my invention to a local operators cord for use in connection with a two-wire multiple switchboard; Fig. 3 shows a nioditied torni of the invention applied to a local opcrators cord-circuit for use in connecting subscribers lines in a three-wire multiple switchboard; `and Fig. fi illustrates the invention applied to a ylocal cord-circuit' for connecting subscribers lines iii a three-wire multiple suf'itch'tuiard, the tfiirrent-disccnnecting relay being` so arranged that but a single winding required therefor, where-as in the preceding' figures each such relay has two windings.

Referring first to Fig'. l, at A is illustrated a subscribers substation circuit con-I nected by a metallic circuit with the exchange and there vnovided with the custo/ni.- ary linerelay 1 which controls call signal 2, the cut-oit' relay 53, and the line jacks oi: the line, of-which a pair only shown .i in

\ 1 s I local operatorls corn-circuit is illustrated,

ing; current to lwhile the comprising the answering plug 5 and the calling plug 16 having lrip and sleeve contacts, the tip contacts being connected by a suitalile conductor in which is inserted the condenser 9, while the sleeve contacts are also connected together, having the condenser connected in the conductor uniting them. Associated with answering plug 5, are the supervisory relays 6 and 7, controlling, as usual, the supervisory signal S; while in association with thecalling plug 16, are the supervisory relays 11 and 12, controlling, usual, the supervisory signal 13. Suitable ringing key connections are illustrated, as are the listening-key levers 15, a test relay 14, and an operators talking set indicated as a whole at L. The particular line and cord-circuits just referred to are of a character well known in theart and further specific reference to their arrangenient. is unnecessary. l have illustrated a pair of multiple trunk jacks 17 connected by suitable trunk conductors with a trunking operators cord-circuit M which may loe assumed to be at a distant exchange. This cord-circuit- M includes the usual repeating coil windings 19 having the high resistance trunk relayY 2O connected between the windings at the answering end of the cord, said relay 20 controlling the guard or disconnect lamp g in the usual manner. The signaling devices at circuit M include also a key lamp l arranged to warn the operator whether or not ringingcurrent has been applied to the called line as hereafter explained, and the calling superyisory lamp C connected in circuit in sugliy uayls to advise the operator of the response-ot thccalled\subscriher. The ringing relay lnnd the sleeve relay 97, associated with the trunk plug 31, are partieularly concerned in the control of the ringing current.x The relay 23 is provided with two windings, one, a, serving to operate the relay toc-anse the connection ot ringconnected telephone line, other, is so connected with respect to the winding a and a suitable source ot energizing current as to serve at thej proper time to prevent the continued efficacy of tflie--windinir c, in which operation the rct es asa-n cnerative-lsimt ,et

the Winding c. in a manner which will be more fully explained when the detailed cir cuits are described in connection with their operation. t

The invention is adapted for use in connection with selective party line ringing and I have accordingly illustrated at the right hand of F ig. l a party telephone line having connected to it the substation H, while taps at H2, H3 and H indicate the connections of other substat-ions similar to H. The said substation may, as indicated, be provided with tuned harmonic bells ot any of the well-known commercial types. The harmonic generators G', G2, G and (it, shown asociated with cord-circuit M, are arranged for connection with the cord strands by the operation of the ringing key plunf ers p', p2, p and p". Thus if the operator depress plunger p', the generator G will be connected to the cord and will project ringing current thereover and over any connected line of a frequency to ring a substation whose bell is attuned like that of H". When plunger p2 is operated to connect generator Gr2 with the cord, ringing current will be projected to ring a substation bell attuned to the second. frequency, and so for the plungers p3 and 794. Each plunger has an insulated end adapted to close a corresponding contact 37', 372, 373 orl 37'", and carries its respective rigid cam member said cani members having suitable engaging pins upon the slidably movable rod 34; controlling the contact spring 3S. `Each generator G has its appropriate continuously rotating interrupter I divided into two segments, one segment of each interruptor being connected to its respective generator, while the other segments have a common connection extending to the battery B having its negative pole grounded. Further, ach interruptor I has a brush connected to the alternate contact 37 of its appropriate generator. Thus, as any interruptor l rotates, it will alternately connect its respective generator G to the respective alternate contact 37 and then substitute for the generator the battery B', this operation being continually re cated at intervals of a few seconds, where Ey the customary periodic ringing is secured.

V "When any plunger 7) is depressed, its cani 35 first shifts rodcflcdownward suthciently to free the cam of lanypreaiously depressed plunger Whose springfwillfrestore it tonormal.l The actuating plunger then closes its contact 3 7, and thee downward stroke is completcdthereaftcr moves rod still farther to close contact 23S-39. The plunger ,'u, after being fully depressed, is released by the operator, and its asf' elated spring moves it lLiacliWa-rd to the idicating7 po sitio; wherein the hoolir t its cani 35 holds it by engaging its ed pin on rod Sit.

A t this time., 'the contact 37 will be closed, but contact 39 will. be open, a momentary impulse through the latter bein all that is necessary for the operation o the system.

In a complete system, there will of course be any required number of line circuits and the usual lesser numbers of local and trunk cord-circuits for interconnecting the lines.

Assuming subscriber A desires to talk with subscriber ll', the removal of the re ceiver at A. operates line relay l to close circuit through and light line lalnp Q, Whereon the operator, answering. will insert plug 5 in an answering jack 4, relays 6 and El then operating in series by current over the sleeve plug and jack contact. The attracted armatures of relay 3 open the circuit of line relay l and' lamp 2 is retired. Said armatures also connect relays 6 and 7 to the line limbs and relay 7 operates by current over the line, preventing at this time the display of supervisory signal 8. The operator, depressing levers 15, 15, learns that the calling subscriber Wishes to converse with subscriber H. in the distant exchange and by order Wire, indicated at 40, advises the trunk operator at M of the number of the subscriber wanted. The trunk operator then assigns the trunk to be used, that one shown in Fig. l, and the local operator inserts )lug 1 6 into the trunk jack 17 before her. lltelay ll then operates by current to ground through impedance 18, and the supervi,C ry lamp 13 is accordingly displayed and the tip cord strand is cour pleted. Current also finds its Way through relay l1, sleeve contact at 16, 17, Wire t, trunk relay Q0, of high resistance, say, tive thousand ohms, returning over Wire t and to ground through relaylQ, which latter, however, because of the'i resistance at 20, tails to operate at this time, allowing lamp 13 to continue lighted. telay 20 atvM, however, operates and displays guard signal g by current to ground at normal contact 28, unless the trunk operator has already inserted plug 3l in jack 4t of the called line. Before doingso, the operator tests the called line in the usual. way, the common test relay 30 being provided for the purpose.

4Assuming the called line idle, the inser tion of plug 31 in a jack thereof operates relays -7 of thel cord and relay 3 of the called line in series by current from batter B to ground over the sleeve plug and jar( contact. Relay 3 then connects the line limbs ci," substation H to the jack contacts, While relay 27, byarmature 2,9, completes the tip cord strand and, by armature 28,` opens a contact in the circuit of guard lauip g, 'putting it out, and closes a Contact in the cir-culs of lamps K and C, which both light. The operator at M noyr actuatcs plunger yi to connect the proper frequency generator G and, as previously mentioned, such actuation results in a continued closure of contact 37 and a momentary closure of contact 38-39. The closure of the latter contact energizes relay 23 by current from ground at relay 3 of line ll. over the sleeve cord strand, contact 23S-39, winding a, and to negative battery at B, it being observed that relay 27 is in shunt of this circuit. Relay 23, by armature 25, locks itself to the sleeve cord strand and, by armature 24, puts out lamp K, whereby the operator knows that the relay 23 has properly operated and that the called subscriber is being rung up. Obviously, had the operator failed to actuate plunger p completely to close contact 38-39, the continued display of the key lamp K would warn her of the fact. Owing to the attraction ot armature 26 and the closure ot contact 37, the interrupter I now avails to alternately connect generator G and positive battery at B through winding Z) of relay '23, alternate contacts 2G and Q9 and the tip plug and jack contact with the limbs of line H, across which the harmonie ringers are bridged as before described.

AUntil a response is made at the called sta-- tion, current from source B is inell'ective because of the substation condenser-s. Generator current from G is, however, effective and passes through the four substations in parallel, actuating the bel'l at H only. The return path of said generator current is traced through sleeve contact at ee--bh through alternate contact Q5, winding a, and t0 ground through the circuit of battery B. Since the twol windings or' relay 23 are unidirectional, the alternations from generator G have no operative effect upon the position of the relay armature mechanism, the saidv relay being practically dit- Y ferential or non-inductive to such alterna- 'be taken into account, the relay remaining energized by thesteadycurrent frorn- B- through winding a and attracted armature Now assume that answer is made at il inf the silent interval, 'z'. e., when inten rupter I has the positive pole of battery B connected to spring 37 iand winding 7).' AThe removal or the receiver at H causes the ltwo 'line limbs to be lconductivelj,

` `bridg'efil Via the upper hook-switch contacts 'ture mechanism will be retracted.

so that current from B flows through winding b, alternate contacts QG and Q9, tip contacts at Bl-, over a line limb through ini-- pedance coil, hook-switch and transmitter at H', back over the opposite line limb, sleeve contacts slr-3l, then branching, part ot' the current lowing through relay QT and to ground through battery B, while the rest flows through alternate contact 25, winding a, battery B to ground. In this connection, it will be observed, lirst, that the removal of the receiver at the substation creates a somewhat heavier tlow of current in winding o, than 'previously existed and that the tiow therethrough is in the samedireetion as before; second, that the current through the winding b is in a direction to tend to induce polarity in the core of relay Q3 opposite to that induced by winding a.

The current through winding will have as a minimum enough eil'ect to neutralize the effect. of winding a, upon the core of relay 23 suiiiciently so that the relays arma- 'l`he arrangement may be such that it' the cord is connected with one ot the telephone .lilies ot' the highest resistance, the current through winding l) will, on response, approximately neutralize the eii'ect of winding a, whereby the armature mechanism will re-l store. rlhen if the cord were connected with some line of relatively low resistance, the response might occasion a 'tlow of current through winding l; ot' suliicient volume, it continued, to reverse the core polarity and build up in the opposite direction. How ever, when in the case of such short line, the current through winding has endured a sutlicient time so that, the core is about neutral, the armature mechanism instantly restores, opening the circuits of both windings, so that the relay will protect itself against being continued locked by the building up ot' a reversed polarity in its core. Obviously, the arrangement is adapted for use with lines having very wide resistance r differences.

Excellenty results may be obtained over lines of widely ditt'rring resistances by maliing thy two batteries B and B each of twenty-four volts, each of the windings a' and b one hundred and sixty ohms, the winding ot relay 2T of one hundred "ohms, and those ot cut-ott' relays 3 of the lines tive hundred ohms. However, these characteristics may be varied, thevonly limiting restriction being that the winding l) oppose the winding' 4 sutliciently to release the armature mechanism at the proper times. The response at substation H has accordingly modified the magnetization of the core of relay 23 to an extent causing the retraction of its armature niechanisrn.r

Circuit through lboth windings of Vrelay causes relay 21, which may have one hundred ohms resistance,y to operate by current through substation H, and sa d, relay, by

its left-hand armatures, establis' es the talkL ing circuit at repeatn coil 19 one of said armatures shunting the five'thousand ohm relay 20 so that sutlicient current'will flow through relay 12 at the local cord to actuate its armature, whereby supervisory signal 13 is retired and the local operator advised of the response. -Further, relay 22, which may be of tive hundred ohms resistance, operates by current through the attracted ri ght arma,- ture of relay 21, flowing to ground through the alternate contact 28, and locks via alternate contact 33. The opening ot normal contact 33 puts out calling lamp C so that the trunk operator is advised ofthe response. Callihg subscriber A and called subscriber H" are now in conversation, the substation transmitters being energized by the central batteries. lhen subscriber A. replaces his receiver, the'circuit oit relay 7 is opened and signal S is displayed. lVhen subscriber H replaces his receiver, the circuit of relay 21 is opened, the relays armatures retract, and the low resistance Vshunt about relay 2O is opened so that the current through relay 12 at the local cord .is diminished to a point- Where its armature retracts to display signal 13. Both signals 8 and 13 being now displayed, the local operator withdraws plugs 5 and 16, restoring` tonormal the calling line and the local cord. The Withdrawal of plug 16 y mature lights guard lampg by current through normal right-hand switch contact of relay 21, alternate contact 2S to ground. The display of the signal g while K and C are undisplayed warns the operator to Withdraw plug 31., which act restoresthe called line and cord M to normal. As before stated, whichever plunger p has been depressed Will remain in the indicating posi tion until another pl anger is depressed. It will be seen that owing to the joint control of lamp g by relays 20 and 21, and the fact that when one is energized the other is de'e'nergized, the operation oit' lamp g as a disconnect signal by current to ground at alternate contact 28 willA only take place when plug 1G is withdrawn.

Il' the response is made at thc called station H during a ringing interval, the current which then flows will also operatively aiiect the relay 23 to dctnergize it, owing to thc altered resistance at the. substation, the generator current will at some period ofits alternations substantially neutralizeI the core of the relay 23.

The connections 'shown in Fig. 2, applying my invention to a local cord-circuit in a two-Wire system.T are in general quite si1nidecncrgizes relay 2O andv its arlar to those of Fig. 1. Here the relay 23 is associated with the calling plug 16 ofthe local cord and the sleeve supervisory relay 11 serves for the shunt for windin a and in the control of key lamp K. In te present case, I have substituted a direct current generator B2, having its negative pole grounded, for the battery B of Fig. 1.

The mechanisms associated with plungers p in Fig. 2 are the same as those of F 1g. 1 and operate in like manner. i

In Fig. 2, the subscriber A initiates his call and the operator answers as in Fig. l. Learning the number of the called line, she tests her multiple jack of that line, the test relay 14, provided for this purpose, being in this instance adapted for connection with the tip pl'ug contact by the operation of the l listening key. Finding the line of H idle, the opera-tog inserts plug'lG-in a jack 4, which actenergizes relays 11 and 3 in series, and she then actuates -the proper plunser p to supply ringin4 current ofthe required frequency. As be'ore, momentary, closure of contact 38-39 operates relay 23, establishing a flow of current trom ground throughy cut-olf relay 3 of the called line, sleeve contact 4,-16, tnence in shunt of relay 11, through contact 38` 38,' winding a to negative battery at B, whereupon armature 25 locks the l relay 23 to maintain it operated. As before,',ar1nture 211 puts out key lamp K, and armature 26, being attracted, connectsgtheringing current )with the tip of plug 16 'and so tothe called line circuit, via. the attract/ed,l right armature of relay 11. If response is lmade in the silent interval, current from positive pole of B2 flows lthrduglrl, 37', in a direction to induce magnetism to oppose the magnetic effect of 'Winding a, over the called line and back to ground throughthe circuit of battery B, the return circuit including parallel paths through relay 11 and winding a. The core of relay 23 is by this current ailected to release lts armature mechanism, which re-` stores to normal. The closing of normal contact 26 operates relay 12 by connecting it with the called line. The attracted armature of relay 12 puts out lamp 13 which was displayed from the time the operator connected With the called line to cause the attraction of the left armature "of relay 11. By such putting out, the operator knows that `the calledy subscriber has answered. ilfurther, the attraction of the armature of relay 12 Tperates` the closing relay 41 which, vbyarlnature 43, locks to ground at the attracted armature of relay 7, by armatures 42 and L1-3 completes the talking circuit at the cord, `and by armature 44 prevents redisplay of key lamp K. Whenat the conclusion of conversation, subscribers A and H replace their receivers, they denerffize respectively relays 7 and 12, to display the signals 8 and 'essi' resaca? 13. Vhen both are displayed, the operator withdraws plugs 5' and"1.6,restoring the line circuits and the cord-circuit 'to normal. The locking Acontact 43 ot relay -tl has its circuit controlled 'by the armature ot relay 7 in order that, it both subscribers depress their hook-levers, the relay 4l may unlock -and denergize. Assuming that subscriber H prematurely replaces his receiver and subscriber A Wishes the operator to again signal substation l-l; subscriber A will olepress and elevate his hook-lever a few times, thus lashing7 lainp- 8 to secure` the operators attention. The first depression of the hook-switch will, by denergizing'relay 7, cause denergization of relay 4l, which Athen remains denergized, until the operator has, at the ealling subscribers request, again actuated the proper plunger to ring the calledv subscriber and the latter has responded. By the arrangement mentioned of relay 41, key lamp K is brought operatively into the operations when a called subscriber has to be rerung, and 'during the reringing the cord is opened at 42, 45, so that ringing current cannot reach the call- Ling line. ln rthe present instance, battery B, having its positive pole grounded', may be of one hundred volts, windings a. and may be each of one hundred and sixty ohms, the windings of relays 1l and l2 of one hundred ohms each, while the windings of the edt-oil' relays 3 of the lines may have tive hundred ohms resista-nce. While other values may obviously be assigned, the above gine excellent results. ln the present case, response during the ringing'flnterfial also releases the relay 23, as explained ii'lf'cdnnee-a tion with the previous ligure.

ln applying my invention y,to .a three-wire system, shown in Fig. 3, a somewhat difterent arrangement from those previously described is employed. Here, uponthe actuation of a plunger p, the closure of con-'tact 3,8439 connects the energizing winding e' in series with the impedance 64 from' ground #at to neg-attive battery B, whereafter the 'attraction of armature 68 continues current vthrough G4 and. a from ground at 59 and 64 is, however, in shunt of windin a with respect to the circuit extending rom the ringing key through the contact 37,. winding b, over the limbs of the called line H an back to armature 67, so that when,`on the response, direct current from source l flows over the line, said impedance 64 serves in adjusting the current flow in winding a .so that the required magnetic etlects upon the core ot' relay 23 are secured. In calling, subscriber A removes his receiver, energizing relay 5l which lights lamp 52, in relspouse to whose signal the operator connects plug 55 with a springjack 54, thereby connecting the heavily marked talking conduc The winding .tending to ground at 59.

hulk! a.

tors of the cord with the line limbs, so that A current circulates trein B, through relay 5T,

over the line limbs, and returns o ground through the lel't upper winding of repeating coil 56. The armatures ot relay 57 thus attract, the lower one shunting supervisory lamp 5S to prevent its display at this time.

-Over the third plug and jatlt contact, relay 53 receives current from battery B and its armatures denergize relay 5l, so that signal 52 is retired. rlhe operator connects her listening set L and learns that subscriber' lil is wanted. Assuming the usual test shows thc called line to be idle, she inserts plug 69 in a multiple jack 54 of the called line, when current will flow Alroni ground at cutoli1 relay 53 of line H, through sleeve plug and jack Contact, larnp G3, relay (il to negative battery E. Supervisory signal G3 is accordingly displayed and relay 53 operates to disconnect line relay 5l. Relay Gl also operates, whereon a circuit may be traced from ground at 59, armature of relay (il, normal Contact G8, key lamp K to battery, Where- As above indicated, when now the operator ac- 4tuates plunger 7,1", relay 23 energizes and attracts its armatures, whereof 68 establishes the maintaining circuit `for winding a, eX-

As long as the substation switch remains depressed, the

current alternations from the ringing generator will have no operative effect upon the armature mechanism ot relay 23, since the windings are disposed to be substantially non-inductive to the ringing alternations, and impedance G4 :forces by far the greater part of, such currents to findl their return through the winding a to battery B. If the subscriber responds in the silent interval, the current from generator B3, having its negative pole grounded, flows through winding o overthe line limbs, through the raised hook-lever at substation H', returning to the attracted .armature 67, and over parallel paths through windings G4 and a. Suicient current will traverse the winding in a direction tendine' to neutralize the magnetic etect of winding a to cause the relay 23 to permit the retraction of its armature mechanism. The retracted armatures of the relay 23 place both its windings onppen circuit. Armatures 6G and 67 close circuit as follows: from ground, through the upper right-hand winding of repeating coil 56, contact 66, tip plug and jack Contact 69-54,

the` hook-lever and transmitter at H, re-

turning through the sleeve talking contact at 54-69, normal contact 6'?, supervisory relay 60, and to negative battery B. Relay 60 attracts its armature to retire supervisory signal 68 by connecting the low resistance4 winding of relay 62 in shunt of said signal. Relay 62 accordingly operates and attracts its armature, locking itself in series with the l0 ground at lamp K to ground at .59. Assuming the lamp K to be an ordinary twenty-four volt sii/*itchboard lamp, and the lriglnt winding of relay 62'to have a resistance of, say, live hundred ohms, the lamp K `will be eatinfui hed at this time so that the retraction o1 armature G8 does not cause a renewed dis la thereof. Then the subscribers at A. an lreplace their receivers, the'fdenergize, respectively, the supervisory relays i7 and 60, whose retracted armatures remove the shunts from supervisory signals and (i3, which are displayed, warning the operator to With-- draw the plugs 55 and (39. Upon the With-v drawal, the line circuits and the cordcircuit Will be at normal. It the subscriber H prematurely replaces his receiver, and sulr scriber A, by deinessing,Y and elevating .his hook-switch, thus flashing lamp 59, signals the operator and asks her to ring subscriber Il a second tiuie, the depression of the hook lever at .A will, by dener Zing relay 57, have caused the locking circuit of the right winding,r of relay 62 to be opened, whereby said relay denergizes and key lamp K is brought into operative relation. with the ground at 59 as soon as the hooleleyer at substation A is raised, so `that the lamp K, in the re-ringing process, as before, serves to Warn the operator it she tails to fully actuate the ringixt/g plunger. ln the present instance, the following values will be :tonnel to give satisfactory results: for direct cur rent generator B3, having its negative pole grounded, one hundred and twenty-tive volts; and for battery B, having; its positive pole grounded, twenty-torn.' volts. The windings a, 'o and (34 may cach be of tivo hundred and titty ohms resistance. The winding of relay (ll, and the non-inductive resistance connected between battery B andA lamp 58, may each be of eightylthree ohms,

while the left-hand lWindingr of relay G2 and the shunting; resistance for lamp 58 may he of 't'orty ohms. The cnt-cti" relays ot' the lines may be ot the usual` resistance, apt proximating thirty ohms.

ln the structure of Fig. 3, the removal ot the receiver at 'Fl' during ythe ringing intcrval \\'ill,hs in the previous cases, avail to'causc the 'relay 23 to permit the release of its armature mechanism.

leferring to Fig. 4, the 'telephone system there. illustrated is quite similar in general arrangement to that of Fija'. I3. llore, however, a relay 72 having` a single Winding is provided for controlling the connection and disconnection ot the ringing mechanism. This relay is first operated on actuation ot' a plunger y. by current from ,around through contact 39m-2ER to negative battery l, d relay then locking. by alternate contaf't t5, The hey lamp K is con trollcd in an oln'ioaal manner by th Witch contact 7 lil/Thile relay :is oneratcd, the

man"

incarner current from a. connected generator G will flow 4through alternate contact 74, over the line limbs to Il', actuating the substation hell, returning through the sleeve talking `contact at i4-69 and to the attracted armaerator B2, having its negative pole ground-A ed, will be connectefil tl'iroug'h the raised hook-lever at the substation with attracted armature. 7G, at which point the current will divide, a part flowing to negative battery B, while the remainder will find its return through relay 72 to ground at 9. The potential thus produced at attracted armature 76 avails to oppose the current previously tioiviug through the relay 72 so that its core has its induced magnetism reduced to an extent such that its armature mechanism is restored to normal. That above 'indicated is a minimum requirement. Pref erahly, however, the resistanccs of the various devices are so proptntioned that the connection of the source B2 on the respouse from a line of relatively low resistance will serve to not only neutralize the core of relay 72, but to tend to build up' therein a polarity opposite to that previously existing, lly such reversal, a reliable throwback `oi. the armature mechanism is secured and at the same time an adequate margin is secured when the relay is to be operated. by current over lilies of high insistance, in which cases the potential at attracted armature 76 may not besu'tlicient to nlorc than reduce the magnetism l oit the core of relay The detailed operation oil the' apparatus of F et sutliciently obyious from the description Ariven in connection with Fig. il and need not be referred to more extensiyely. `Removal of the receiver' at H in the ringing interval will release. the relay TQ, since, because of the change of resistance at the siibstation, the ,generator current will at sonic period of its altcrnations sub stantially neutralize the direct current passiner through. said relay.

Values suitable tor the structure of Fig. fl; are, for the liiattery B, having its positive nolo -grounded, twenty-four volts; 'for the direct current generator 4B2, ha ving its negative pole ,f ronndcd, one hundred volts; for

ifaiues .may be employed.

insane? lt will be understood that the drawings are purely diagrammatic in character and no attempt has been made to indicate the precise mechanical embodiments of the yarious mechanisms.

That various changes may be made in the precise methods shownA and described, is obvious. For instance, the use ot polarized electromagnetic devices will Vreadily suggest. itself to those skilled in the art as a means adapted to secure a modiiied form of this invention; or the employment of sri-called double-acting7 relays, in which a limited energization is produced to cause one operative position of the switch contacts, and a greater energization to produce another position of the switch contacts, would be. a means likely to suggest itself to 'those desiring to practice my invention in moditied form. Thus, in a general way, the present invention contemplates the use of a single relay which, in the first instance, is eo'nnected in closed circuit with a source of current to operate to connect ringing current with aline. whereafter an additional circuit is established for it to cause ay further electromagnetic iniiuence to be impressed upon it, whereby the relay opens the connection to the source ot ringing current.

I claim as Iny invention?- 1. A telephonei'system including a telephone line, a connection for projecting signaling current thercover, a relay for closing and opening said connection, a circuit for initially energizing said relay. a connection controlled by said relay for locking it during signaling, a source oi current, and a switch at the substation of said line for operation to conductively unite a pole of said source with said relay, said relay being then eiiective to open said connection.

2. A telephone system including a telephone line, a. connection for projecting signaling current thereover, a switch contact included in said connection, a relay, means for eiiecting a tiow of current through said relay to cause it to close said contact, and a switch connected in said telephone line and in circuit with said relal for effecting a different flow of current tirough said relay to cause it to open said contact.

3. A. telephone syst-em including a telephone line, a connection korqiroiecting signaling current thereover, a switch contact included in said connection,` a relay, means for etecting a flow of current through said relay to cause it to close said contact, a

4. A telephone systemiincluding a telephone line, a signaling source for connection therewith, switch mechanism, a relay serving when energized to operate said mechanism to connect said source to said line, and a circuit including a switch contact of said.

relay and the limbs of said telephone line for passing current through said relay to cause it to disconnect said source from said line.

5. A telephone system including a telephone line, a signaling source for connection therewith, switch mechanism, a relaylserving` when energized` to operate said mechanism to connect said source to said line, and a circuit including the limbs of said telephone line for passing current through said relay to cause it to disconnect said source from said line.

.6. A telephone system includinga tele- 'plione line, a source oi signaling current, a

initially energizing said relay, a connectiony controlled by said relay for locking said re' lay when it is initial, energized, awinding for said relay, a soi rce of current,'and a switch at the substation of saildline for operation to conductively imite a pole of said Source to said winding, said relay being then edective to open said locking connection.

-8. A telephone system including telephone lines, a link-circuit tor interchangeable connection therewith, a source of current` for connection with said link-circuit to signal axv connected telephone line, a switch contact controlling connection and disconnection of said source and circuit, a relay, a circuit l0- .calv to the exchange for ef'ecting a flow of 115 current through said relay to cause it to hold said contact closed, a locking switch contact of said relay includedl in said circuit, 'and a switch at the substation of a connected telephone line in circuit with said Contact and12o adaptedwhen closed to effect a different iiow of current. through said`relay to cause it to open said contacts. i 4

9. A\telephone system including telephone lines, a link-circuit tor interchangeable connection therewith, a source of .current for connection with said linkcircuit to signal a connected telephone line, a switchcontact controlling connection and disconnection of said source and circuit, a relay controlling Asaid contact,a winding-of ljsadfrelay adaptnected withsaidjtelephone line in' response to the energization `of said tirst winding, and a switch in the connected telephone line for etfecting an energization of said Vsecond winding to cause said relay to open said contact.

10. A- telephone system including telephone lines, a link-circuit for interchangeable connection therewith, a source-of current, for connection with said link-circuit to signal a connected telephone line, a switch contact controlling connection and' disconnection of said source and circuit, a. relav controlling said contact, a winding of said relay adapted to be energized by current local to the exchange to cause said relay to close said contact, a second winding for said relay, and a hook-switch in the connected telephone line effective on a response thereover to energize said Second winding in opposition to said tirst winding, whereby said relay opens said Contact.

11, A telephone system including telephone lines, a link-circuit for interchangeable connection therewith, a source of currentfor connection with said link-circuit to signal aconnected telephone line,`a switch contact cruitrollingr connection and disconnection ot' said source and circuit, a relay controlling said contact, a winding of. said relay adapted to be energized by current local vto the exchange to cause said relay to close said contact, a second winding for said relay coiinected responsive to the energization of said first winding with said telephone line, and a hook-switch in the connected telephone line eti'ective on a response t-hereorer to energize said second winding in opposition to said tirst winding whereby said relay opens said contact.

12. A telephone system including telephone lilies, a link-circuit for interchangeable connection therewith, a source of eurrent for connection with said link-circuit to signal a connected telephone line, a switch contact controlling connection and disconnection of said Lsource and circuit, a relay having two windings and controlling said contact, means .ffor initially energizing said relay to close said contact, conductors for said link-circuit in' circuit with the lirnbs of one of said lilies and extended to connection current to operatively neutralize said lirst winding.

13. A telephone system including telephone lines, a link-circuit for interchangeable connect-ion therewith, a source of cur- `rent for connection with said link-circuit, to

signal a connected telephone line, a switch contact controlling connection and disconnection of Said source and circuit, a rela)y having two windings and controlling said contact, means for initially energizing said relay to close said contact, a locking circuit Ycompleted by the energized relay to maintain it in, closed circuit, said locking circuit including one of said windings, conductors for said link-circuit in` circuit with the limbs of one of said lines and extended to connection with said windings respectively by the energization of said relay, connections for passing current troni said signaling source over said telephone line and differentially through .said windings, said 'relay being unresponsive to the signaling currents, a. switch at the substation adapted on response to close a conductive circuit through said second winding, and a resistance at the exchange connected in circuit with oneof said windings and proportioned to adjust the tiow of current through said windings on the response to operativel)iY dernagnetize said relay.

14. A telephone `system incliuiing telephone lines, a link-circuit for interchangeable connection therewith, a, source of our rent for connection with said link-circuit to signal a connected telephone line, a switch contact controlling connection and disconnection of said source and circui.ta rela5v having two windings and controlling said Contact, means for initially energizing, said relay to close said contact, @,cbuduciiois tot said link-circuit in circuit with the xlimbs of one of said lines and extended to connection with said windings respectively by the energization of said relay, connections for passing current from said signaling source over said telephone line and differentially through said windings, said relay being unresponsive to the signaling currents, a switch at the substation adapted on response to close a conductive circuit through said seeond winding, and a resistance at the exchange connected in circuit with one of' said windings and proportioned to adjust the How of current through said windings on the response to operatively deniaguetize said relay.

l5.-A telephone system including telephone lines, a link-circuit for interchangeable eonnection therewitll, a source of current for connection with said link-circuit to signal a connected telephone line, a switch contact controlling connection and discounection olf said source and circuit. a. relay having two windings and controlling said ineens? cont-act, means for initially energizing said relay to close said contact, a locking circuit completed by the energized relay to maintain it in closed circuit, said locking 5 circuit including one of said windings, conductors for said link-circuit in circuit with the limbs 'of one of said lines and extended to connection with said windings respectivelyby the energization of said relay, connections for passing current from said signaling source over said telephone line and dierentially through said windings, said relay being unresponsive to the signaling currents, a switch at thesubstation adapted on rs )onse to close a conductive circuit.

throng said second winding and an inductive device connected in shuntl of said irst winding and oiiering high impedance sistance to the signalingcurrents, said device being proportioned to adjust, upon response at the. substation, the current flow through said windings to operatively deniagnetize said relay.

vl telephone system including telephone lines, ,a link-circuitfor interchangeable connection therewith, a source of current foricoiinectio with said link-circuit to signal' a connecte telep one line, a switch contact controlling connection and disconnection of said source and circuit, a relay having two windings and controlling said contact, `means tor initially energizingsaid relay to close said Contact, a locking circuit completed. by the energized relay to maintain it in closed circuit, said locking circuit .including one of said windings, conductors for said link-circuit in circuit with the limbs of one of said lines and extended to connection with said windings respectively by tbc energization ofsaid relay, connections for passing current from said signaling source over said telephone line and differentially through said windings, said relay being unresponsive to the signaling currents, a switch at the substation adapted on response to close a conductive circuit 'through said second winding, an inductive device connected in shunt of said first winding and oli'ering impedance to the signaling currents, said device being proportioned to adjust, upc-n response at the substation, the current iiow through said windings to operatively dernagnetize said relay, and an armature released upon such demagnetization to eect disconnection of said `windings and said conductors and the opening of said locking circuit.. A

17, A telephone system comprising a telcphone line extending from a central station to a substation, a call-receiving device and a hook-switch at the substation, calling apparatus at /the central otlice, a relay oper-- ating on energization to put said calling apparatus to line, and a contact ot said switch- 65 hook for closure in circuit with said relay,

controlling its energization to disconnect said calling apparatus.

18. in a telephone syste-in, a telephone line extending troni a central station to a substation, a call--rcceii ng device and a hookswitch the substation, calling apparatus at the central ofiicc, a relay operating on energization by current local to the exchange to put said calling apparatus to line, and a contact of said switch-hook for closurein circuit with said relay, controlling its connections to cause it to disconnect said calling apparatus.

19. ln a telephone system, a telephone line extending tro a central station to a substation, a call-receiving device and a hook- 's'iteh at the substation, calling apparatus at the central office, a relay operating on cnergization to put said calling apparatus* to line, and a contact of said switch-hook for closure in circuit with said relay, adapted to control it to disconnect said calling apparatus.

20. ln a telephone system, a telephone line` extending from a, central station to a substation, a call-receiving device and a hookswitch at the substation, calling apparatus at the central oiiice, a relay operating on energization by current local to the eX- changeito put said calling apparatus to line, and a Contact of said switch-hook in circuit with said relay for closurel to cause said relay to disconnect said calling apparatus.

2l. A telephone systein including a telephone line extending from a central station to a substation, a call-receiving device and a hoolt-swvitcloat the substation, calling apparatus at the central oilice, a relay operating on energization to put said calling apparatus to hne,` and a contact of said switchhook for closure in circuit with-said relay;n

controlling its connections to cause it to disconnect said calling apparatus.

a telephone system including a telephone line extending from a central station to a substation, a call-receiving device and a hook-switch the subst-atibn, calling apparatus the central otlce, and a relay operating on encrgization to connect said calling apparatus to iine and directly actuated by current in said line to disconnect said cailing apparatus.

23, A telephone system including a telephone line extending -from a central station to a substation, a call-receiving device and a hook-switch at the substation, calling apparatus at the central ottice, and a relay directly operated by current to connect said calling apparatus to line and directly operated by currentin the line to disconnect said calling apparatus.

24. A telephone system including a telephone line attending lroca a central station to a substation, a call-receiving device and a hook-switch at the substation, calling apparatus` at the central office, and a relay directly operated by current controlled at the exclninge to connect said calling appa ratus to line and directly operate-d by current through the substation to disconnect said calling:r apparatus.

25. In a telephone system, a telephone line extending trema substation to the eX- change, a signal-receiving device and a switch. at the substation, signal-actuating apparatus, a relay, a circuit adapted when closed to produce and maintain an initial energization of said relay, a switch conu tact of said relay actuated in response to said initial energization to connect said line with said relay, a source oi current to pro-- duce a different energization of said relay on the closing of said substation switch, and a switch contact of said relay actuated in response to said initial energization to connect said apparatus to said line and to said different energization to disconnect said apparatus from said line.

26. In a telephone system, a telephone line extending from a substation to the exchan e, a signalreceiving device and a switci at the substation, signal-actuating apparatus, a relay, a circuit local to the ex" change adapted when closed to produce and maintain an initial energization of said re lay, a source of current to produce a different energization ot said relay on the closing of said substation switch, and a switch contact of said relay I'actuated in response to said initial energization to connect said ap paratus to said line and to said different energization to disconnect. said apparatus from said line.

27. In vtelephone system, a telephone line extending from a substation to the exchange, a switch at the substation, signalactuatingr apparatus, a relay, two windings for said relay, means for initially energizing,r said relay by closingr a circuit local to the exchange through one winding of said relay, a source ot' current to produce a dilt'erent energization of said relay on the closing of 'said substation switch by 'passingu current through said other winding, and switch mechanisn'i of said relay actuated in response to said initial energization to conv neet said ainiaratus to said line and to said dilferent energization to disconnect said apparatus .trom said line.

28. A telephone tcm including'` a telew phone line extei'ujlii t troni 'f salutation to the exchange, a switch at the substation,

signal-actuatinnl apparatus, a relay, a ciu 4cuit to initially energize said relay, a s yitch contact ot said relay actuated in response ,to said initial. energization to connect said line with said relay, a source of cinrcnt Vto produce a different energiaation of said relay on the closing: of said substation switch,

anda switch contact of said relay actuated' in response to said initial energizaiion to connect said apparatus to said line and to saiddilterent onergization to disconnect said apparatus from said line.

29. In a telephone exchange systeim the combination with a telephone line extend ing to an exchange, oit' a substation switclr hook, an electrormignet connected in a controlling circuit, a first branch of said circuit, a second branch of said circuit including a contact of said switch-hook, means whereby current in only the first branch causes one energization ot' said magnet and current in both branches causes a dilierentcnergization of said magnet, and calling apparatus at the exchange connected to line by operation ot' said magnet in response to said one energization and disconnected from line by the (mei-ation of said magnet in response to said diil'erent energization.

30. In a telephone exchange system, the combination with a telephone line extending to an exchange, ot' a substation switclrhook, an electromagnet connected in a controlling ci` cuit, a first branch of said circuit, a second branch of said circuit including a contact' of said switch-hook, means for causing current in the first brai'lcl'i to cause one enen gization ol? said magnet, means controlled by said contact to close a circuit of said second branch to cause a different energization of said magnet, and a connection tor operatively establishing' ringingr current to line, said connection being closed by said one energization and later opened byV said other energization.

3l. In a tcleiiihonc exchange system, the con'ibination with a telephone line extend ingr to an exchange, of a substation s\\'itcli hoolc` an electromag'net connected in a controlling circuit, a Erst branch of said circuit, a second branch ot said circuit including:r a contact of said switclnbloclt, means for causing' current in the til'st branch to cause one energizalion ot said nmgnct, means con irolled by said contact to alte-r said circuit so that current [lows in both branches to produce a dittercnt energif/iation of said magnet` and calling apparatus ai the cxcliango connected to line by operation of said magnet in response to said one encrg zation and disconnected trom line by the operation oiE said magnet in response to said dillcrent cnergization.

In a telephone cxchanffc system, the combination Vwitl a hflephone line extending to an exchange. ol a substation switch-hwk, an electromagnet connectml in a controllingf circuit, a first branch ot said circuit, a sccond branch of said circuit including a contact of said switclrhook, means hereby current in only the first branch causes one energization ,ot said magnet and current in both branches causes a different encrgization. of said magnet, and a connection for Leases? vthe indication of said'signal when said switch is actuated, and means for maintain?` ing the altered indication when said switch is restored.

34. The combination Wit-h a telephone line, of an operator controlled connection device adapted for adjustment to connection with said line, a switch for applyingcall ing current"'to said line, a signal for said switch sensitive to connection of said device and line, means for retiring said signal when'said switch is actuated, and means for preventing .restoration of said signal on restoration of said switch.

I35. In a telephone system, the combina tion with a telephone line, oi" an operators link-circuit having a normally open contact in thel talking circuit and connected with said line, signal-actuating apparatus for said circuit ,in operative relation with said line, a relay controlled over the line circuit for terminating said relation, a supervisory relay controlled through contacts of said relay, and an armature for said supervisory relay for directiy closing said normally open contact when said relation is terminated.

36. In a telephone system, the combination with a telephone line, of an operator"s link-circuit having a normally open Contact in the talking circuit and connected with said line, signal-actuating apparatus for said circuit in operative Arelation With said line, a relay controlled by a response over said line for terminating said relation, and a second relay adapted to be operated by currentover said telephone line for closing said normally open contact in response to the operation of said relay.

37. In a telephone system, a'pair of telephone lines, a link-circuit connected to said "lines, a repeating coil interposed between "said lines 1n a circuit normally inductlvely discontinuous at the exchange, signal-actuating apparatus, a switch and associated relay operative to associate said apparatus with one of said lines While leaving said repeating coil circuit inductively discontinuous at the exchange, a second relay controlled by said first relay and operative by current over one of said lines to render said repeating coil circuit inductively continuous at the exchange.

38. ln a telephone system, telephone lines, a link-circuit normally inductively' discontinuous at the exchange, a repeating coil interposed in said link-circuit, means for connecting the opposite ends of said link-- circuit each. 'to a diderent line While leaving said link-circuit inductively discontinuous at the exchange, ringing apparatus and an operators key for said circuit 'for actuation to operatively associate said apparatus With a connected line While leaving said linkcircuit inductively discontinuous at the eX- change, Ineans controlled over said connected line to terminate the operative association oi the ringing apparatus therewith, and a device for rendering said linkcircuit inductiveiy continuous at the exchange after operation of said means.

39. In a telephone system, tWo connected telephone lines, a repeating coil circuit interposed between said lines and normally inductively discontinuous at the exchange, ringing'apparatus and an operators key for actuation to operatively associate said apparatus with one connected line While leaving said repeating coil circuit inductively discontinuous at the exchange, means controlled over said one line to terminate the operative association of the ringing apparatus therewith, and a supervisory relay operating in response to said means to render said repeating coil circuit inductively continuous at the exchange.

40. A telephone system including two connected telephone lines, a ringing generator, a switch adapted 'when actuated td e'ect connections including the ringing generator in circuit, a repeating coilinterposed between said lines in an inductively discontinuous circuit, and electromagnetic means operated when the substation telephone is removed from the hook to restore said switch and to render saidrcircuit inductively continuous.

in witness whereof, hereunto subscribe my name this 24th day of Nov., 1908.

HARRY G. WEBSTER.

Witnesses:

CAROLYN Wenen, G. E. MUELLER.

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