US2339872A - Remote control system - Google Patents

Description

A. B. MILLER REMOTE CONTROL SYSTEM v Jan. 25, 1944.

4 Sheets-Sheet 1 Filed vJuly 22, 1941 INVENTOR Alfred BMiZ Zer Jan. 25, 1944.

A. B. MILLER REMOTE CONTROL SYSTEM I Filed July 22, 1941 4 Sheets-Sheet 2 aw M l\ x 3 M 3 vii Rm m L E m 1 F 1% N E k m g Q. 53 i5 "Jam u fl Q .m; u, fimfiiwl 5 m 5 Q5 Nam w a? K INVENTQR XZfrecZBMzZZ61 5' Kit/Leg HIS ATTORNEY Jan. 25, 1944. A. B. MILLER REMOTE CONTROL SYSTEM Filed July 22, 1941 4 Sheets-Sheet.3

BY BZWZZer QR Maia INVENTOR Alfred HIS ATTORNEY Jan. 25, 1944.

A. B. MILLER REMOTE -CONTROL SYSTEM 4 Sheets+Sheet 4 Filed July 22, 1941 Dispzzi'zherfs Office CTU Siaiion Fig?) CTC Siaii on v CTC Office V INVENTOR HIS ATTORNEY Patented Jan. 25, 1944 REMOTE CONTROL SYSTEM p Alfred B. Miller, Edgewood,Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application July 22,

9 Claims. 7

-relays than are usually required in systems of this character, and by arranging the apparatus so that only two line wires are required,.which may be used jointly byother communication facilities, such as .a dispatchers. telephone line equipped with a call selector system, without interference.

My invention is an improvement uponthose disclosed in the Baughman and Agnew application, Serial No. 326,440, filed March 28, 1940, now Patent No. 2,303,875, issued December 1, 1942, for Remote control systems, and in the Snavely, Miller and Jackel application, Serial No. 366,874, filed November 23, 1940, now Patent No. 2,292,245, issued August 4:, 1942, for Remote controlsystems. H I shall describe one. form of apparatus embodying my invention by first. explaining the functions of the various parts and by. then tracing the circuits in detail, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1A, 1B, 2 and 3, inclusive, form a diagrammatic view illustrating in condensed form a centralized traff c control system comprising a specific embodiment of my invention, inwhich Figs. 1A and 113 comprise the central officeequip-ment, Fig. 2 shows the apparatus at a typical field station, and Fig. 40

3 shows typical line circuits. V I I,

-Similar reference characters refer to similar parts in each of the several views.

The system of my invention is of the coded duplex type employing two line channels, comprising a main stepping and control line channel and a subordinate message or indication line channel, but these are arrangedv in a manner analogous to the well-known simplex telegraph circuit that only two line wires. are, required. The stepping line channel employs the two line wires in parallel as one side ofa grounded "line circuit, while the message line channel is a metallic circuit employing the two line wires in *series-and is superimposed'upon the telephone 1941, Serial No. 403,494

circuit by interposing a suitable low pass filterat each point of c'onnectio riof the 'C. T. C. apparatus I to' the line wires, the telephone apparatus being'connected tome line wires through condensers or high pass'filter s I Referring to Fig. 3, theline'wire's employed by systemas shown herein aredes'ignated'y and '2; respectively, and provide a telephone channel extending from a' set of telephone apparatus'fi located at the .point designated Dispatchers office to a similar set of apparatus 5 located at 'the'opposite' end of the line, as shown, or to one of a plurality of intermediate'points such as the one designated Selector station on the draw- 5 ings, a suitable high pass filter as indicated by the condenser 6 beinginterposed between each set or telephone apparatus and theline wires.

" The "dispatchers 'oflice is'also'provide'd'with a selector system for selectively calling the telephone stations, which is tobe understood to be of the type shownin the FieldPatent-No. 1,343,256, granted June '15, 1920, having a plurality of code wheels such asthe wheel-89; by meansof which the operator at the dispatchers 5 oflice may transmit'imp'ulse codes to selectively call the way stations to establish telephone communication therewith. The selector system includes the-selectors 12 for operating call bells 16 at the station, and at the dispatchers oifice includ'es a selector battery .85, a connector relay 86 and'a pole changer relay 8]. All of these devices are similar to the correspondingly desig- "nated devices or the Field patent'a-nd their detailed operation may be understood by. reference to the patent, with one -exception,.which is that -in Fig. 3 the battery 85 is not connected directly to the line by the operation of relay..86, but a transformer l is interposed, an arrangement which is well-known and widely used. v;

It has been assumed that the dispatchers of.- fice and the C. 'I. C. control office are at dlfi61 -ent locations, as shown.- The stepping .line

channel of the 0. 1. C. system .extendsfroma connection togroundat. the .C. T. C voflice, ov er contacts of apair. of transmitter relays Ill and T2 through a line battery Bil to one terminal of each of .two balancing resistors 8, the remaining terminals. of which are,,connected through a fil- .ter l2, across the line wires y and a. When re I .lay T1 or .T2.is picked, up, positiveor negative current, respectively, flows .irom'battery' 8il ovel line .Wires, y and z in parallel and .r fiturns to ground and thence back to battery over a plurality of multiple paths, including one at each 555 station, eachsuch path comprising a balanced connection from line wires or and 2 through a filter l2, resistors 9, and the windings of the line relays R3, RI and R2 to ground.

Relay R3 is of relatively high resistance as compared with the resistance of the line wires, and the stick polar type, such for example, as that shown in the Snavely Patent No. 2,140,604, granted December 20, 1938, and its armature normally occupies its left-hand position, as shown, but as relay R3 is connected across line wires y and 2 it is non-responsive to current from battery B in the stepping line channel since this flows in opposite directions in the two windings of relay R3. Relays RI and R2 are also high resistance polar relays of thesamegeneral type, but these relays are biased as indicated conventionally by a spring, as shown, so that their,

armatures occupy the right-hand position when the relay is deenergized, or when energized tby positive current flowing from right to left through -thewinding, as indicatedby the position of relay R2,-andthe armatures assume the left-hand posi- "tion'only when positive current flows from *left to right through the winding-asindicated by'tlre position of relay Rl. 'In other'words; relay R-l responds only 'to positive current and relay R2 "to negative current, as indicated conventionally by the signs "and on these relays in the drawings. a 1 a The'stepping line channel'is used for the transmission of impulse codes from the C. T. C. 'o'lfice to the stations. To transmit a code, reiays TI and T2 are energized alternately or repeatedly one'at a time to transmit impulse codes comprising a series of short impulses of selected polarity to operate 'the'line relaysRi and R2 at each C. T. CLstation. 'Each code includes a'first l group'of impulses constituting a station code call i'or .s'electingthe desired'stati'on, and a second "group of impulses ioroperating movable devices at theselected station to one position or another according to the relative polarity of the impulses. The message line channel is a metallic-circuit which may :bQ traced in Fig, 3 from the positive terminal of a line battery 3i over a back contact ..3J o f al-ine relay F, the contacts of a line pole- ,ch anger relay T3, the right-hand side of the -associated filter 12 to, line, Wire 1 and thence lthroughaplurality ofpaths, in multiple, to line wire 2,,each of which paths includes inseries the windings of a linerelay R3 and the associated resistors Stand filter l2, the circuit being com- :pleted from line wire 2 through the left-hand side ofithe office filter l2 and the primary oi atransformer 13 to the negative terminal of battery 8i.

Relay T3 is normallypicked up, and the relays ..R3 .are normally energized by positive current in line wire y to hold their left-hand contacts closed as shown. V V

The relays R3 are used as cycle marking relays to .mark the beginning and end of aseries of imipulses constitutinga code, andare controlled over the messageline channel by the transmission of a single long impulse of reverse polarity corre- -=sponding to the series of impulses transmitted (over the-stepping line andconstituting .a .code. "That-is, relay T3 is released and consequently each-relay R3 is reversed'for the-duration of: each 0. T. C=. coda-and the apparatus .at each C..T. C. field station is conditioned to, initiate its response "-to a code transmitted over the stepping line channel only when the associated line relay R3 is normal and to-respond-to the successive st'epsof "thecode only when relay R3 is reversed,--and-is o restored to normal by that relay at the end of each code.

When the system is at rest, the message line channel is employed for the transmission of starting impulses from the C. T. C. stations to the C. T. C. office for initiating the operation of the system in response to a change in conditions at a station, .and when the system is in operation, it is employed for transmitting indication impulses for indicating station conditions at the oifice. Such impulses are transmitted by temporarily connecting the line wires y and 2 together through a shunt circuit path as indicated diagrammatically by the contacts l4, l5 and 16 in Fig. 3. The closing of contact 14, for exam- ,ple,is without efiect upon the telephone channel because filter I2 is interposed, and it is also without eifec't upon relay R3 because that relay is of the stick polar type and remains in its last operated position when deenergized. The current flowing through the shunting .contaot l4, results in an increase in the current drawnfrom battery 8| and flowing Jin-theprimary of transformer [3 at the office. Relay OR is a stick polar relay having a line winding connected to the secondary'o'f transformer 13, and is arranged like therelay OR of the Baughman and Agnew application hereinbefore referred to, to operate its contacts to the right in response to each:increase in the .current suppliedLto transformer 13 as described. As hereinafter explained in detail, relay OR isirestored locally after each operation; its response to the operation of a starting contact such as M is employed to initiate the transmission of codes over the stepping .line channel, and the position of relay 'OR on .certain :steps .of a code, which depends upon whether or not contacts such as I5 and I6 are closed at the time, is employed to indicate at the office, the position of these contacts. t

- In its specific embodiment as herein illustrated, the C. T. C. system of myvinvention is applied to the control of 7 manual lolo ck signals for governing train movements in territory of relatively light trafiic not equipped with continuous trackzcir- -cuits, such as that illustrated by the track diagraminFlg. 3, and also for reporting to the control ofiice the movements of trains in such territory. Mysystem isflpeculiarly suitedv to suchtan application because of itsrelatively low cost due to thecomparatively small number of relays re.- quired at :each field station. n

Referring now to Fig. .2, the track diagram thereon representsa typical field location and -shows a pair of opposing .manual-block signals lLandJRlocated in ashort isolated detector track section havinga track relay TR. Thesig- 'n'als are illustrated-as of the .color light type, having lamps-R, Yand .G for indicating stop, permissive, and clear, respectively, and they are manually governed by signal control relays LHS, 'RHS and DS-of:the stick polarrtype. A track stick relay TS is also:provided, having a pick- -up circuit closedoverlcontacts IN of relays LHS and RHS'when these relays occupy their normal 'or-stoppositions 'asshown, with relay TR energized. Relay TS alsohas "a stickcircuit including its-own front contact I! and the front contact iii of relay TR, as shown. Each signalin- -dicates stop-either when its control relay LHS or RHS is normal or when relay TS is released, andindicatestpermissive :or clear, according to the positionrof relay DS, when its control relay .is reversedwith relay'TS pickedup. The signals -;are restored automatically to stop when; a train ,enters the detector track section and; remain at steam it is vacated, and thesubsequent clearing of either signal can be effected only'if the operato t re o t e v sl e at s al ent 'ql to n ma to c p la TS.- The. signal h cl, e sv e ontro dlhy ,means'oi impulse codes transmitted from the ot- ;he e over the stepping line channel. In its spe; c ific embodiment asshown herein, the appalatus i s arranged so that each code includes a group ,of iourstation selecting impulses which maybe .ar fanged in difierent combinations of positive and negative polarity to provide station code calls for sixteen stations like v that oi Fig z,

and each code call is iollowed by four, function j impulses received at the selected station only. .Tl iree of the latter control the stick polar relays and DS, respectively, according ,to their relative polarity, the fourth being, available ior any desired purpose suchas ior operatingamaintainefs call signaL- Each code may also include the transmission otimpuises over the message line channel for operating a group of four indication relays such as; the relays ITK, ISK, IHK and: IDK i Fig. ;1B, for indicating the condition of four de- ,vices at' the selected station The shunting oi the message line channel by contacts such as l5 and Hi to transmit these indications occursduring the eth to 7th steps ,resiaectively, of the'code transmitted over the stepping line channel and takes place only at the called station. f- It is to be understood that suitable local sources of current are provided for energizing all oithe relays shown herein except those controlled over the line. Each local source isindicated by rei'erence characters B designating the positive lor supplyterminal and C the negative or common return terminal of the source., to the ol la s-n i $9 b o maeach. s operatedtothe left when terminal B is connected to'i'ts l ft nand terminal. Certain of these have double windings, and are operated to the right when terminal 3 is connected to the right hand terminal of asecond winding, Those havingsin: gle windings, such as relays lH K operated to the right by connecting thel negatlve d LH re ;terminal l l"oi a second source oif curreht to the left-hand terminal of its winding, terminal Q c 'on stituting'the positive terminal of thisfsecond source. Certain of the neutral relays are made slow release in a well-known manner by the", provision, or" electronic rectifiers connected across their windingslaswill be apparent irom th' a i Thestation apparatus of Fig. 2 includes a starting relay ST, normally heldenerigieed over a stick circuit i'ricludingfcontact leer relay IR an contact '22 of relay TS, which circuit opens to release relay ST in response to any change the position of relay TRor TS. Relay ST npen'releasing'closes the contact I l hereinbefore referred to in connection with Fig. to trans mit a starting impulse to the office, becoming reenergised upon receipt of the corresponding code call.

With the apparatus arranged as shown Fig, 2 the, first'indication step, that is theeone transmitted on the fourth code step, is contrplled by relayfifR, the corresponding indication relay ITK, at the, officebeing reversed bythe code, if Qntact i5, is closed, and being restored locally to normal-i1" contact is open during tnisstep, to thereby indicate at the officewhether or not tneidetectorl ti'ack e t qci .occu d, I

' -Th'e indication-impulse transmitted on the fifth code stepficontrols relay ISK at the omce accordingito thejposition of relay S, to report whether or not a train which has just vacated the detector section is complete and intact, re-

lay S being controlled by devices disclosed in the copending applications, Serial No. 396,731,

filed June 5, 1 941, by H. A. Wallace, and Serial No. 396,745, filed on the same day by G. W. Baughman, for Train detecting and reporting apparatus. For an understanding of the relation of these devices to-the present invention, it will sufiice to point out'that each train moving over the .contr olled territory is required to be provided with a rear-end marker in addition to those required by the usual operating rules, comprising a magnet-M, mounted at the rear of the train in sucha position that it will come into inductive relation with a trackway inductor I as the rear of the train, passes through thetdetector track section; Accordingly, if the train is complete and; intact with magnet M in the prop er position, anelectromotive force is induced in inductor. I to pickup a relay S which relay is of agsensitive; biased polar type, relay S then being held energized overa stick circuit including its own contact 20 and back contact H of relay TS. Contact ,2! of relay S provides a means (corresponding ;t0 contact l6 referred to in connection with Fig. 3) for indicating the condition of that relay on theassigned step of each code., i V

The operator at thev ofiice after receiving a report that a complete train has passed out of the track section at a sta-tion,-m-ay restore relay LHS or RHS to normal to pick up relay TS,

whereupon relay S is released by the opening of vback contact of relay TS, and the starting relay ST; is again released by the operation of contact 22-. of relay TS to initiate a new cycle of operation tocancel the, train report, contact 2! of relaysbeingopeng c The indication transmitted on the sixth code step is controlledby contactAR of relay LHS or RI-IS to indicate when. one of these relays is reversed; while that transmitted on the seventh step is controlled by contact 4R of relay DS. Since these relays are operated at the beginning of thefifth, sixth and seventh steps, respectively,

f sufiiciently slow in releasing so that it remains picked up until ,the next stepping relay is fully picked up. Relay vlP is operated over back contacts 2R of linerelays RI and R2 provided relay R3 is normal, when, the stepping line channel is first opened to begin a code. Relays 2P, 3?, 4B and LP are energized over front contacts IN of. relay Rigor R2 in response to the first four impulses of a code but only if these are arranged in accordance with the code call for the station, 7

as determined by adju table Jumper connections, as shown in 2. Relay Yl is a half-step relay operated to the left and topthe right alternately over contactsBZ of the stepping relays during the intervals between impulses and provides stick circuit connections for the proper operation of these relays. Relay GR is a stick relay picked .upat themeginning of the fourth step at th'e selected station onl-y, rendering rlays 2 PQ3P and ll? 'at that station responsive to the 5th to lthimpulss irrespective of -their polarity, and also cooperates with the -stepping -relays to preparethe circuits for receiving controls an'd trans- :mit'ting indications.

.- Relay -L is'a' slow release relay required only thoughit will be apparent that as many may be provided as there are available code calls. Each storage unit, as shown, includes a'connector relay such as'I'S, and a group of apparatus controlled thereby. The circuits over contacts -'B'l'to B4, inelusiye, ofrelay. =|S include adjustable jumper connections and are for controlling the transmitter relays Tl and T2 of Fig, 1A to determine the station code call, and those'o-ver contacts C1 to "C4 of relay IS 'control'relays TI and'TZ to determine the polarity of the function steps according to the-positions-of control levers such as iI-IL and IDL. Contacts DI to D4 of relay is prepare circuits for the indication relays :iTK, etc., Which are energized :by current of normal or reverse polarity :according to the position of a repeating relay ORP controlled iby the message line relay OR.

t-"It-is 'to'be understood that the contacts 2L and ZRiof leVer ll-IL in its center or normal position as shown control the character of code elements for operating relays LI-IS and vRHS of Fig. 2 to normal, and that LHS or RHS is reversed, by the code element transmitted when the .lever .occupies its left-handorright-hand position, respectively. Relays LHS and RHS .in their normal position control .the indication relay iHKto normal .to light lamp INE. Relay lI-IK is operated to reverse when either .relay LI-IS or RHS is reversed, but lamp ILYE or IRYELis lighted only when lever IHL is :in a corresponding left-hand or right-hand position with relay lHK reversed and relay lDK normal. JReIayDS of Fig. 2-is controlled to normal with ilever I'DL in its center wpositionand is reversed withlever .IDL in either its left hand or right-hand position, while relay lDK repeats the position of DS, lighting lamp ILGEor IRGE, .according to the position of-lever iHL when reIaysII-IKLand lDKzare both reversed. The control levers are preferably of a type diclosed inanapplication Serial No.i3.81,062, filed February 28, 1941, by Snavelyand Zetwo, for Circuit controllers, now Patent .No. 2,289,736, granted July '14, .1942, andthe lmovable element is not only rotatable to left or right to operate control contacts as described but is also operableinanaxial direction to serve'as apush huttonf for opening a starting contact Al-g The pusncontacts A I- of the control levers are all connected in' series in thestickcircu'it for' a normally energized ofiice starting relayOSTfshown in Fig. lA,"and an operating cycle or the system is-initiated by openingthis circuit in response to theoperation of-any control lever. This'circuit also includes'aback contact-.6301 relay QRP controlled by the line relay 0R; whereby the system is initiated by the operation of relay GR. in response toth'e release of the starting relay ST at anystatioiar 1 "The system -as shown is so arranged that in response to each-initiationit operates througha cycle which includes-the transmission pf a-complete code -as above describedto each station in :turn, including the transmission of indications from each station during the transmission of the corresponding code; That is, -wheneverrelayST is re1eased;-provided ---t-he system is not-already in operation, the connector relay is "becomes energized, "so that the first code transmitted will be -the-one for station -No. 1. Relay-0ST energizes a storing relayST-Ppwhich energizes a master relay 0M, releasing relay T3 to revers the-pm lar'ity -oi the current supplied to *the message line, and placing the stepping line transmitters T1 and T2 under the controlof relay lS.--'An auxiliary-relay TA controlled by relays -T-l and T2 causes these relays to operate repeatedly at theproperrateto transmit'the code.

' The-oflice apparatusgas shown in Fig. =1A, also includes a chain of :stepping relays IP to 5P,

. and stick polar "relays Y1 and OCR which func- 'tion in-a manner corresponding generally to that of the similarly designated "relays of Fig. 2e1- readydescribed. v A

-The-ofilce stepping relays l'P-to iP-are controlled 'directly by-the transmitter relays'Ti and T2, relay iP operating when the stepping line is first opened'and relays 2P to '5P responding successivelyas relays TI and-Iipick up to transmit steps l-to 4 of 'the code, constituting the station code call, in unison with therelays 2P, 3P, 4P and 'IP at station No;- 1, -under-th -control of relay "Y1. )Thenthe office -relay "-2P, 3P and if operate on steps 5; 6 and 7 of the code in unison with-thecorrespondingstation relays, relay -OGR being reversed at the beginning -of the fifth step, and "finally, relay SP is operated by relay I'l on theeighth'step; The-"relays 48328, etc.,- "form a chain ofrelayssimilar to there'lay's PP, *2P,-etc.',- -butcontrolled by a stick-relay Y2 so that they are operated *one ata time in order, one =for'each-code. Thatis, "the operationof relay 5P on'stepB causes relaylsto'pick -up-and relay IS to release. ReIay-"JP then causes the energization of 'relay '-'l-T to initiate a Qth-step, reenergizing relay T3 and releasing relay T3? to restore the transmitting and receiving-appar-atus *to normal. Relay "OST,"-however, remains released, 'and relays S'IP, OM and '28 remain picked up; a new 'code is therefore initiate in response to the release of relay T3P,-'compris'in'g eight steps of whichthe characteriscontrolled by circuits 'over contacts -of relay 2S and-"Which therefore governs the apparatus at-stationNo'. 2. On the last-step of 'this code, that-is, 'on'the 1-7-th step'of the cycle,'-assuming-there are but two stations, the final relay 88 'of the connector re lay chain is operated, relay "0ST =is -reenergized and relays '-STP and OM released and all "apparatusis-restored to 'norma'ltocomplete the cycle. "The-oldies apparatus also includes a relay *F which remain deenergized in normal operation butwhich is provided for the purpose of preventing interference b'etween"th -C. T. C. and selector-systems.

Relay Fis controlled dicated in Fig. 3 by apparatus=-siInilar--to that shown in a copending application, Serial -No. 4013092, filed-July 5, 194-1, byG. --W. Baughm-an and N. -F. Agnew, for Bemotecontrol-syste'msa will b apparent from Fig. 3, relay F is'connecte'dthrough anamplifier A and a transformer 25 havingits primary connected through condensers 21 across the line Wires YandZ. I Whenever the operator at the dispatchers office releases a code wheel such as 89, the connector relay'86 is energized to connect battery 85 to the primary of transformer 9 and to short circuit the condenser 28 in the secondary circuit of transformer 9, for the duration of a cod delivered by the pole-changer relay 81 according to the arrangement of the code wheel teeth. As long as relay 86 is energized, altematin-g current supplied from terminals BX and CK of a suitable source to the primary of transformer 29 is delivered through a tuned circuit comprising its secondary and the condensers 30 over the lower contacts of relay 86 through transformer 9 to line wires y and z, and thus to the primary of transformer 26, which is tuned to the frequency of this current by condensers 21, with the result that relay F repeats the position of relay 86 and is picked up for the duration of each selector code. It has been found in practice thatsatisfactory operation of this arrangement may be secured by connecting terminals BX and CK toa 6 cycle source, the line current required for operation of relay-F being of low value and practically inaudible in the telephones 5, and the selectors 12 are wholly'non-responsiv to the current from transformer 29.

-It will be seen that when relay F is picked up its back contact 3| disconnects battery 8| from line wires y and z and thereby prevents interference with the operation of the selectors 12. Contact 32 of relay F also opens, disconnecting terminal B of the local source of current from the stick circuits for relays DST and STP. If a C. T. C. code is being transmitted and relay STP is picked up at the time, it will be released, deenergizing the circuits for the relays IS, 28, etc., to stop further transmission. In any case the release of relay 0ST causes the initiation of an operating cycle of the C. T. C. system following each selector code. It will be seen that the selector system is operable at all times regardless of the condition ofthe C. T. 0. system, without interference, and result of the operation of a code wheel being to cause the operation of both systems. I

Having thus explained the mode of operation of my apparatus, I shall now trace the circuits in detail, starting with the apparatus in its normal condition and assuming that levers IHL and IDL are operated to the right to change the indication of signal IR from stop torclear. Normally relays TI, TA, T3 and CST at the oiiice, Fig. 1A, are energized, and likewise relays RI, R3 and ST of Fig. 2 at each station. Relay T! is energized over its stick circuit extending from terminal B at back contact 32 of relay F, back contact C3 of relay OM, front contact 04 and winding of relay TI to terminal C. Relay TA is energized over a circuit having a multiple connection to terminal B at front contacts A3 and D5 of relays TI and T3. Relay T3 is picked up over a circuit from terminal B, contact C5 of relay TI, back contact C5 of relay OM, relay T3 to terminal C and is held energized over a stick circuit including its own contact A3. Relay 0ST is energized over a stick circuit from terminal B over contact 32 of relay F, wire 33, contacts Al of all the contact levers of Fig. 1B, in series, wire 34, contact C3 of relay ORP, contact IN and thempper winding of relay 0ST to terminal C.

' When the operator opens one of the lever con-" tacts Al, relay 0ST releases, completing a pick-' up circuit for relay IS from terminal B at contact 4R of relay 0ST, contacts A5 of relays STP'and OM, wire 35, relay IS to terminal C. Relay IS picks up and completes a circuit for relayYZ from terminal B at back contact D5 of relay 5P, contact C2 of relay T3, wire 36, con tact AI of relay IS and the upper winding'of relay Y2 to terminal C, operating relay Y2 'to the left. I When the operator completes the movement of levers IHL and IDL to the right and releases these levers, terminal B at contact 32 of relay F becomes connectedover wires 33 and '34 to contact A4 of relay IS and thence to wire 31 to complete a pick-up circuit forrelay STP over contact C3 of relay T3, contact Bl of relay T3P, contact 2R of relay 0ST, relay STP to terminal C. Relay STP picks up, its contact -A3 completing its stick circuit extending to 'ter minal B over wires'34 and 33, and its contact A2 completing apick-up circuit for relay OM from terminal B at wire 33 over contacts A2 of relays TA and A4 of relay 33 (Fig. 1B) in multiple, to wire 48, thence over contact A2 of relay STP through relay OM to terminal C.

Relay OMpicks up and completes its stick on cuit to wire 48 over its contact A4 and also com-' pletesa stick circuit for relay IS from terminal B at contact B4'of relay OM, contacts CI of relay 5P, C6 of relay 2P and 2N of relay OCR in multiple to 'wire38, thenceover contact 2N of relay Y2, contact A2 andwinding of relay IS" to terminal- C. a 5

Relay TI is released by the opening of back contact C3 of relay OM, and opens the stepping line 'circuitat its contacts B2 and B5, releasing relay RI at 'each' station, and circuits are closed over back contacts D5fof relays'TI and T2 to; maintain relay OR normal, and over back contacts" A3 of relays TI and T2 and front contact C4 of relay T3 to-pic'k' up'the' oflice relay IP him then completes'a circuit at' its'contact C5 to operaterelayOCR to the left.

The release of relay RI at each station com pletesa' pick-up circuit for the associatedrelay' stantially in unison. Each relay IP at'its con tact B2 completes a circuit for operating the associated relay YI to the left.

The circuit for relay T3 is opened at contact C6 of rel'ay'TI and after a short period relay T3 releases. Its contacts B2 and B5 reverseth'ej polarity" supplied to the message: line, thereby reversing relay R3 at each station and each relay R3 energizes the'a'ssociated slow release relay L. The pick upcircuits for all IP relays are now open, butthe oflice r'elayIP is held energized over astick circuit from terminal B at back contact D5 of relay T3 over back contacts D3 contact 2R of relay R3, contacts 4R of relaysf RI and R2, contact IN of relay YI, contact A2 and winding of relay IP to terminal C. Relay A5 completes a circuit to T3 at its back contact .v w pick up rel' y T3P, which relay remains picked up for tl'ie duration of the code, and'at'its con j tact C2: opens the circuit overwire 36 forrelay; Y2, "but relay Y2 being of the stick polar type- IP overfcontact s '2R'of relays RI and R2 and contact IN of'relay R3, so that the relays IP pick up at the o-fiice and at each station sub- IP to terminal IP at each station is held ener'-' remains to the left to maintain the stick circuit for relay IS closed. Relay T3 at its front contact D5 opens the circuit for relay TA which releases after a brief period First step Either relay T1 or T2 maybe energized to make the first impulse positive or negative according to jthe'code call desired, by connecting contact BI of relay IS either to wire H, as shown, or to wire 42. A similar connectionover contact B3 of relay IIS controls the character of the third step, while the second and fourth steps are made positive by connecting contacts B2 and B4 of relay IS to wire 4?, and made negative by connecting these contacts to wire 44. With the jumper connections as shown, the code call for stationNo. 1 comprises four positive impulses while that for station No. 2 comprises three positive impulses and. one negative impulse.

When relay TA releases to :begin the first step, it completes at its contact 04 a pick-up circuit for relay TI extending from terminal .3 at contact 2 of a hand stepping switch HS, contact 3N of relay OCR, contact B6 of relay IP, wire 5I, contact BI f relayIS, wire 4I, contact 2N of relay YI, .front contact 03 of relay OM, back contact C4 of relay TA, relay TI to terminal C. Relay TI picks up, applying positive current to the stepping line channel to pick up relay RI at each station. Relay TI reenergizes relay TA but remains picked up over a stick circuit comprising a, branch; or the circuit just traced which includes its own front contact C4, and energizes the ofiice relay 2P over a circuit from terminal B at back contact D of relay T3, front contact D3 of relayTI, contact 3N of relay YI contact A4 of relay IP, relay 2P to terminal :0, and relay 2? at its contact A2 completes a stick circuit .over contact 3N of relay YI. Relay YI is deenergized by the opening of back contact A3 of relay TI but remains in its last operated or left-hand position.

At each station the energ-ization of relay RI deenergizes YI which remains in its left-hand position, and if the station is arranged to receive a first positive impulse, relay RI completes a circuit for the station stepping relay 2P from terminal B at contact 2R of relay R3, contact IN of relay RI, contact 2N of relay YI, contact A6 of relay I P, relay 2P to terminal C, and 'each station relay 2? having the proper jumper connection picks up to complete its stick circuit at its contact A2 Each station relay I P is deenergized by the opening of contact 4R of relay RI and releases after a short period. I

The oilice relay IP is similarly released by the opening of back contact D3 of relay TI, opening the circuit for relay OCR, which however remains in its left-hand position. Relay IP also opens the circuit for relay "TI at its contact B6. Relax T-I then releases, opening the stepping line torelease the relays RI, and closing a circuit from terminal Bat its back contact A3 over contact B2 of relay 2? tooperate relay YI to the right, while at each station at which relay 2P is picked up, relay 'YI is operated to the right by relay RI over a similar circuit extending to terminal B at con-,

tact 2-R of relay RI. The release of relays TI a d RI opens the stick circuits for the relays 2P extending over their own contacts A2 and the lefthand contacts of -Y-I, but as soon as the relays YI reverse, new stick circuits .for the relays 2P are completed over their contacts A4 and the righthand contacts of relays YI. The relays YI also prep are pick-up: circuits for relays 3P .byclosing their right-hand contacts.

Relay 'I'I upon releasing deenergizes relay TA which also releases after a short period and terminates the interval following the first step .by completing a new pick-up circuit for relay TI or T2.

, 1 Secondstep RelayTI picks up over a circuitfrom terminal B at switch HS over-contact 3N o'f relay :QGR, contact Bfiof relay 2 P", wire 52, contact B2 of i'elay IS, wire 43, contact 2R, of relay YI, frontcon tact C3 of relay QM, back contact C4 of relay'TA, relay TI to terminal C, and completes its stick circuit at its own contact 04. Relay TI reenergizes relay TA, applies positive current to the stepping line channel, energizing relay RI at each station, and also picks up the ofiice stepping relay 3P over a circuit including contact 3R of relay YI and contact AG' of relay ZP, and relay 3P completes its stick circuit at its contact A2. At each station'for which'the first two impulses of the code call are positive, relay SP is picked up by relay R-I over a similar circuit, and completes a stick circuit at its contact A2. The relays 2P are deenergized' due to the opening of the stlckcircults including their contactA4, by relays TI and RI, respectively, and release after a short period, theofiice relay "2P opening the circuit for relay TI which releases to terminate the impulse thereby releasing the line relays RI. Each relay Y] is then operated to the'left over contact B2 of relay 3P, and a new stick circuit for each energized re lay 3P is completed over its contact A4 and a left-hand contact of relay YI.

Relay 'TI upon releasing deenergizes relay TA, which also releases after a short period and terminates the interval following the secondstep, thereby completing a new pick-up circuit for relay Tl orTZ.

Third step Relay TI .picks up over acircuit extending from terminalB at switch HS over contact 3N of relay OCR, contact 136 of relay 3P, wire 53, contact B3 of relay-SI, Wire 4| and thence as for the first step, through relay TI to terminal C. Relay TI reenergizes relay TA, applies positive current to the stepping line channel, energizing relay RI at each station, and also picks up the ofilce stepping relay 4? over a circuit-including contact A6 of relay 3P and relay 4P completes a stick circuit at its contact A2. the first three impulses of the code call are positive, relay 4? is picked up by relay RI over a similar circuit and completes a stick circuit at its contact A2. The relays 3P are deen-ergized and release after a short period, the office relay 3P opening the'circuit for relay TI which releases to terminate the impulse thereby releasing the line relays RI Each energized relay 4P prepares a circuit for the associated relay YI, over its contact B2, so that these relays YI are now operated to the right, and a new stick circuit for each energized relay 6P is completed over its contact A4 and a right-hand contact of relay Y'I.

Relay Ti upon releasing deenergizes relay TA which releases and terminates the interval following the third step by completing a new pickup circuit for relay TI or T2.

Fourth step Relay T! picks up over a circuit extending from terminal B at switch HS over contact 3N of relay OCR, contact B5 of relay 4P, wire 54, contact B4 At each station for which a code call of four positive impulses, relay IP is. picked up by relay RI over a circuit includingv contact 2R.of relay Yl, contact A6 of relay 4? and back contact C of relay CR, relay IP completing its stick circuit at its own contact A4.

The relays 4P are now deenergized and release after a short period, but before the station relay 4P releases, that is, while relays 4P and IP are both picked up, a pick-up circuit for relay CR is closed momentarily from terminal B at contact 4R of relay R3, contacts B6 of relays 4P and IP, relay OR to terminal C. Relay CR picks up completing its stick circuitat its own contact A3. At the same time, a circuit path is prepared for shunting the message line at station No. l to transmit the first indication impulse in case relay TR is released. This shunt path may be traced in Fig. 2 from line wire 1/ over contact I5 of relay TR, contacts D3 of relays 4? and IP to line wire 2. A circuit is closed at this time over contacts C3 of relays 4P and IP to pick up the station starting relay ST if this relay has been released.

The front contacts B6 and C3 of relay CR now short circuit the jumper connections in the pickup circuits for the station stepping relays at station No. 1, thereby conditioning these relays to respond to the remaining impulses of the code regardless of their polarity.

The ofiice relay 4P upon releasing opens the circuit ,for relay TI, which releases to terminate the impulse thereby releasing the line relays RI.

At the office, relay YI is operated to the left over contact B2 of relay 5P, completing a new stick circuit for relay 5P at its own contact A4.

At station No. I, relay YI is operated to the left over contact-B2 of relay IP completing a new stick circuit for relay IP at its own contact A2.

Each time relay TI or T2 releases during the code, relay OR is operated to the left over its local circuit including contacts D5 of relays TI and T2, consequently relay ORP is now deenergized.

Relay TI upon releasing deenergizes relay TA but before relay TA releases to terminate the interval following the fourth impulse a circuit is closed momentarily to operate the indication relay ITK. This circuit extends from terminalB at back contact B2 of relay ORP, contacts A5 of relays TI and T2, contact A3 of relay TA, contact B2 of relay OM, contact IN of relay OCR, contact D3 of relay 5?, wire 6!, contact DI of relay IS, relay ITK to terminal C, energizing relay ITK in the normal direction as shown.

Relay TA upon releasing completes a new pickup circuit for relay TI or T2.

Fifth step The character of this step is determined by the position of contact 2L of lever Il-IL, this contact being in its upper position when lever iI-IL is-in its right-hand position, as assumed. Relay TI picks up over a circuit including contact B6 of relay 5?, wire 55, contact CI of relay IS, contact 2L of lever IHL and wire lI. Relay TI reenergizes relay TA, applies positive current to the stepping line channel, energizing relay RI at each station, and also picks up the office stepping relay 2? over a circuit including contact A6 of relay EP, and contact 4N of relay OCR, relay'2P completing its stick circuit at its own contact A2. At station No. 1, relay 2? picks up over a circuit which is the same as for the first step, and at the same time relay LHS is energized momen tarily in the normal direction over a circuit from terminal B at contact 3N of relay RI, contact 4N of relay YI, contacts B4 of relays CR and; IP, contact 39 of relay TR, relay LHS, contact IN of relay DS to terminal C. The omce relay 5P and the station relay IP- are now deenergized and release after a short period, relay IP opening the circuit for relay LHS just traced, but while the office relays SP and 2P are both picked up a circuit is closed momentarily from terminal B over contact D5 of these relays to operate relay OCR to the right. At the same time, that is while relays IP and 2P are both picked up at station No. 1, a shunt circuit path is prepared for transmitting the second indication impulse in case relay S is released,- which extends from line wire 1/ over contact 2I of relay S, contacts C5 of relays IP and 2?, con: tact A5 of relay CR to line wire 2. The reversal of relay OCR opens its contact 3N in the circuit for relay TI, and relay TI releases to terminate the impulse thereby releasing the line relays RI, relays YI being operated to the right at the office and at station No. 1 as on the first step to complete new stick circuits for re-' lays 2P.

Relay TI upon releasing deenergizes relay TA, but before relay TA releases to terminate the interval following the fifth impulse, relay ORP being deenergizeda circuit is closed momentarily to operate the indication relay ISK. This circuit extends from terminal-B at back contact'B2" of relay ORP over a path already traced to con-- tact IR of relay OCR, thence over contact D3 of. relay 2?, wire 62, contact D2 ofrelay IS, relay I SK to'terminal C, energizing relay ISK in thenormal direction as shown. Relay TA upon releasing completes a new pickupv circuit for relay TI or T2.

Sixth step completes its stick circuit at its own contact C4,

reenergizes relay TA by closing its contact A3, applies negative current to the stepping line channel to energize relay R2 at each station and, also picks up the ofiice stepping relay 3P by'closing its front contact D3.

At station No. 1, relay'3P is picked up over acircuit from terminal B at contact 2R of relay R3,'contact IN of relay R2, contact 3R of relay YI, contact C3 of relay CR, contact A3 of relay 2P, relay 3P to terminal C,'and relay 3]? completes its stick circuit over its own contactAZ.

At the same time, relay RHS is operated to the right over a circuit closed momentarily from terminal C at contact IN of relay DSthrough relay- RHS, contact 40 of relay TR, contact 134 ofrelayv 2P, back contact D5 of relay IP, contact B2 of relay CR, contact 4R of relay YI, and contact 3N;

o'f rrelay R2 to the negative terminal N of the second local source hereinbefore referred to.

Relays 2P are now deenergized due to the opening of their stick circuits by relays T2 and R2 to line wire 2.

.At the ofiice, relay OR is operated to close its contact IR by an impulse delivered by transformer I3 correspondingto the increment in the current from battery .8I which flows through the shunt .path at station No. 1. Relay ORP therefore picks up over the circuit extending to terminal B at contact C3 of relay TA and is held energized over the stick circuit including its own contact A3.

"The release of the oflice relay 2P opens the circuit for relay T2, which releases to terminate the sixth impulse, releasing .the line relays R2. Relays YI are operated to the left in response to the closing of back contact A3 of relay T2 and contact 2R of relay R2, and relays 3P complete new stick circuits at their contacts A4.

Relay T2 upon releasing deenergizes relay TA but before relay TA releases to terminate the interval following the sixth impulse, a circuit is closed momentarily to operate the indication relay IHK. This circuit extends from terminal C through relay I I-IK, contact D3 of relayIS, wire 63, contact D3 of relay 3P, contact IR of relay OCR and thence over contact B2 of relay M, contact A3 of relay TA, contacts A of relays T2 and TI to terminal N at front contact B2 of relay ORP.

7 Relay IHK is thus operated to the right, and

at the same time relay OR is restored to' the left by the closing of back contact D5 of relay T2. Relay TA upon releasing completes a new pickup circuit for relay TI or T2 and by opening its contact C3 releases relay ORP.

Seventh step Since lever IDL is in its right-hand position relay 'T2 picks up over a circuit from terminal B over contact B4 of relay 3P, wire 51, contact C3 of relay IS, lower contact IR of lever I'DL, wire 42 and contact IN of relay YI. Relay T2 reenergizes relay TA, applies negative current to the stepping line channel to energize relay R2 at each station and also picks up the office relay 4P by closing its front contact D3.

At station No. 1, relay AP is picked up over a circuit including contact IN of relay R2, contact 3N of relay YI, contact B6 of relay CR and contact A6 of relay SP, and completes the usual stick circuit and at the same time relay DS is operated to the right over a circuit closed momentarily from terminal C through relay DS, contacts B4 of relays 3? and CR, contact 4N of relay YI, contact 3N of relay R2 to terminal N.

Relay 3P are now deenergized and release after a short period, the station relay 3P opening the circuit for relay DS just traced. Relay DS being quick acting operates to the right slightly before relay AP is fully picked up, and during the period when relays 3P and 4P are both picked up the message line channel is shunted by the closing of the circuit path extending from line wire y, contact 50 of relay TS, contact 4R of relay DS, contacts C5 of relays 4P and 3P and contact A5 of relay CR to line wire a.

At the office, relay OR which was restored to its left-hand position during the preceding in' terval, is now operated to the right and relay ORP picks up, as on the sixth step.

The release of the oflice relay 3]? opens the circuit for relay T2, which releases to terminate the seventh impulse, releasing the line relays ,RZ. Relays YI are operated to the right to complete new stick circuits for relays 4? in response to the closing of back contact A3 of relay T2 and contact 2R of relay R2.

Relay'TZ upon releasing deenergizes relay TA but before relay TA releases to terminate the in terval following the seventh impulse a circuit is closed momentarily to operate the indication relay IDK. This circuit extends from terminal C through relay IDK, contact D4 of relay IS, wire 64,contact D3 of relay 3P, and thence to terminal N at front contact B2 of relay ORP.

Relay IDK is thus operated to the right, completin a circuit for lighting lamp IRGE which extends from terminal B at contact IR of relay IHK over contact 2R of relay I DK through lamp IRGE to terminal C at the lower contact IR of lever IHL.

At station No. 1, lamp G of signal IR is lighted to cause signal IR to display a clear indication, over the circuit from terminal B at front contact 23 of relay TS, contact 3N of relay LI-IS, contacts 3R of relays RHS and DS, lamp G to terminal C, while the opposing signal IL is caused to display a stop indication because its lamp L is lighted over a circuit including front contact 24 of relay TS and contact 2R of relay Rl-IS.

As in the case of the preceding steps, step '7 is completed when relay TA releases to prepare a new pick-up circuit for relay TI or T2, and to release relay ORP.

Eighth step Relay TI picks up over a circuit from terminal B, contact 2 of switch HS, contact 3R of relay OCR, contact B4 of relay 4P, wire 58, contact C4 of relay IS to wire 43, thence oV'er contact 2R of relay YI, contact C3 of relay OM, contact C4 of relay TA, relay TI Relay TI reenergizes relay TA, applies positive current to the stepping line channel to energize relay RI at each station and also deenergizes the office relay 4P and picks up the oflice relay 5P as on the fourth step.

At station No. 1, relay RI opens the stick cir cuit for relay 4P, but the pick-up circuit for relay IP over contact A6 of relay AP is now open at back contact C5 of relay CR and relay IP is not operated. A control circuit is now prepared momentarily over contact 3N of relay RI and contact B4 of relay 4P, but this is not used in the present instance. Relay 4? releases after a short period, terminating the effective operations at station No. 1, while at the other stations the operations were terminated on one or another of the steps of the station code call.

When the office relay 5P picks up on this step it closes a pick-up circuit for relay 2S from terminal B at contact B4 of relay OM, contact 2R of relay OCR, back contact CI of relay 2P, contact C5 of relay 5P, wire 45, contact IN of relay Y2, contact A3 of relay IS through relay" 28 to terminal C. Relay 28 picks up and com-.1

to terminal C.

ass-acre 9 pletesv its: stick" circuit at; its: own contact: A2.v comprising. a branch of the: pick up circuit:- just traced. The stick circuit for relay. IS extend-- ing; oyer wire- 38 is opened atrback contact. Ci

of relaySP, since the contacts 2N of. relay:OCR.-- 5

and C5 of relay'2P which shunt this contact-are: now open, so that relay ls'releases after a shortv period;

The. release .of the ofiice relay; i]? opens; the

circuit. for relay T-l' which. releases: to:- terminate which releases to: terminate-the interval follow-- ing. thev eighth impulse. and completes. 8.1 new pick-up circuit-for relayyTl.

Ninth step Relay Tl picksupi over a circuit comprising'a' connection from-terminal B over contact B4. of" relay fiP'extending directlytowir'e 4 I I Relay Tl reenergizes relayTA, appliespositive current to the stepping -linejchanne1' to energize the line up circuit for the office relay 2P comple ed on step 5 over contact A6 ofrelayxBP is 'nowopen" at contact-EN of relay. OCRJand relay 2P is i'not" operated;

Relay '5? releases-after aishort period; completing a' pick-up circuit; for relay T3 from" terminalB at contactCt of relay .1 i; back" contactCS of relay-5P, wire 46';'contact A5 of;relay terminal CI Relay T3 picks up, restoring "the :polaritypf" the. message line channel to norrnah. thereby causing. the line relays R3 to. close. their lefthand contactaand at'its contact'D3completes a circuit over contact C3 of relay T3? to maintain 'relayioRi'normal; Each'relay R3 prepares a pick-up circuitfor the associated relay IP;. and at station'No. 1 relay R3ireleases'relays CR? and. L. Relayj'Tii alsov closesja circuit from terminal B at back contact 135 of relay 5?, conjtactCZ of relay'T3', wire36; contact'Al. ofrelay ZSthrough relay Y2 to terminaIjCjoperating'jre lay Y2 to the "right; thereby 'completing'anew stickcircuitfor relay 2Sv over itsi-owni contact" 5o lay. T3 and contact. C4 ioflrelay-Tl and. relay 6 TA .is held'energized over .front-contact .D5 of relay T3. Relay. T3Pfis deenergizedty the. opening of back contactDS of .-relay..T3 and re-. I

leases after a short period, .opening..the ,circui-t for..-relay .Tl at :its contact A3: Relay T l their releases terminating: .theninth impulse of ..5th e. cycle; deenergizing relay T3 and the :linerelays RI and. energizingtherrelays lR-preci'selyasmce curred .whenrelay eTJ waszreleased .pri'or tonnestransmission of: the 1 first step-40f :the: code; .as 1: already described. l The upper wincling oiceaclirelay Yl is nowenergized over contact 32 of -the associated relay I P; sothat any 'relay --Y-I- which isfrest'ored to normal. Relay OCR is restored to-normalby the 'energization ofits upper winding over contact C5 of the ofice relay' IP.

Relay T3 releases after a short period" and de'energizes relay. TA,- which then releases to terminate the interval follow-ing'the ninth step of the cycle; and to prepare a new pick-up" circuit for relay Tl or T2.

Steps w to 1?,inclusz'oe The condition of: the apparatus at the beginning.. of. the tenth stepis the same as at the beginning. ofthe firs'tstepexcept that relay Y2 is now reversed and relays Tl andT2 arenow under thecontrol'ofrelay 2S in place of relay--- IS. stepslortovll constitute an aneight step code: including .iour steps constituting the code call for station' -No; 2 and iour iunction steps controllableby leverssuch as ZHL and ZDL, in

* a manner similarto that already described, and a detailed description appears *unne'cessary. It

will be assumed;therefore, that these steps have been-transmitted.

At th'e-beginning of tl'i'el7th'step of the-cycle,-

relays, Rl deenergizeslrelay. w Thefpick; 25 comprising the eighth step of the secondcode,

relay Tl is-" pickedupover a circuit from terminallB, contact? of switch HS; contact 3R of relay'OCR',-contact B4 of relay iP, wire 58, contact'C i of relay 2S andwire t3; thence as previouslytraced through relay TI to terminal C. Relay Ti 'reenergiz esrelay TA, applies positive current to the-stepping line-channel 'to' energize relay RI at each station; and" also deen'ergizes' the ofllce relay 4? and picks up relayfil? as on the eighth step. At station No; 2, relay RI opens the stick circuit" for relay 4P which releases terminating the operations at that station.

When the ofiic'e'relay tP'picksup" on this step it cl'oses'a pick-upcircuit' for relay SSTrom'ter minal B at contact B4 ofrelay OM; contact 2R of relay OCR, contact CI of relay 2?, contact Ci? of relay 5P, Wire 35; contact IR of relay Y2, contact A3 of relay 2S through relay 33 to terminal C.l Relay 3S picksup and completes a stick cir- 4 cuit.extendingto terminal B over Wire45', at'its Back contact "'0! of relay 5P own contact A2; opens the stick circuit for relay; is over wire '38, and relay, 2S ,releases. after a short period.

releasing,,.the line relays. and operating the OffiCB relay Y to the left?" to complete a new'stick'" circuitfor relay 5?. RelayTl also deenergizes'" relay ".TA which'releases' to prepare a new pick up. circuit for relay T i.

picked up; .its'contact At bridging contact A2 of 'relay TA in the stickcircuit for relay OM" is open, consequentlythe opening of contact A2 of" relay 'TA' disconnects terminal B fromwire 38", deenergizing relay OM:

Return to-.--nomal Relay is' energized over contact B l i ofrelay connection -directly to-wire 33 ion energizing relay T I Relay T I] thereforepicks 'up regardless of the release-of- -relay and establishes its vnormal stick circuit over its-own'contact Clex' tendingover wire- 33 to terminal B atb'ackcom tact '32 of relay "FE RelayTI reenergizesrelay TA applies positive current to the stepping -line channel td reen'ergize the line relays-RE deenera happens-to -=l,la e ben lef-t' in' its reverse-'position ;-=gizes relay'fP, which --releas'es after a shortp'eri Relay lPup'on' releasingfjdeenergizes relay Tl which frel'eas'es gtojtermin'ate the 17thimpulse;

Sincerelay 38 18 W od.- Relay TI also completes a pick-up circuit momentarily for relay ST, extending .fromt.er-= minal B at back contact. D of relay T3 over.

front contact D3 of relay Tl, contact 3N of relay, Yl, contact A6 of relay 5P, contact 4R of relay OCR, wire 25, contact A3 of relay 3S, wire 49, contact A4 of relay STP through the lower winding of relay 0ST to terminal C. I Y

Relay 0ST picks up, completing its stick cir cuit at its contact IN, and opening the stick circuit for relay STP, which releases.

When relay OM releases, it completes a pick-.

up circuit for relay T3 at back contact C5 of relay OM, extending to terminal B at contact C5.

of relayIl, and relay T3 picks up, restoringthe message line polarity tonormal, and causing the relays R3 to close their left-hand contacts,

thereby releasing relay CR at station No. 2 and deenergizing relay'L at each station. The release of relay OM also disconnects terminal B from wire 45, deenergizing relay 3S which releases. Relay T3 upon picking up deenergizes relay T3P which releases after a short period completing the restoration of the apparatus to normal.

It will next be assumed that a train enters the track section as station No. l, releasing relays TR, TS and ST and restoring signal IR to stop. If the line circuits are in their normal closed condition, contact I4 of relay ST will apply a shunt to the message line channel reversing the office line relay OR and picking up relay ORP, which by opening its contact Q3 will release relay OST to initiate an operating cycle.

During this cycle relay ST at station No. 1 will be reenergized on the fourth step as above described, and relay ITK will be reversed to light lamp ITE at the end of that step.

It may happen that relay ST is released during the transmission of a cycle but after the fourth step of the corresponding station code call has been transmitted. In this case relay ST will be in its released position when the line cir-' cuits are restored to normal at the end of the cycle. At that time relay OR is in its normal position, having been operated to that position when relay T3 picked up to restore relays R3 to normal at the end of the cycle. At that time, relay T3 deenergizes'relay T3A, and each relay R3 deenergizes the associated relay L; Relay L has a longer release periodthan relay T3A and its back contact Cl therefore applies a shunt to the message line in case contact I4 of relay ST is closed, to reverse relay OR shortly after relay OR has been positioned to normal, and its local circuit opened by the release of relay T3A. It will be seen therefore that relay 0R will be operated to reverse to initiate a new cycle in the event relay ST at any stations is in its deenergized condition at the end of a cycle.

It may also happen that one of the lever contacts Al is opened during the transmission of a cycle. This will open the connection from terminal B to wire 34, deenergizing relay STE, and

thereby preventing relay 0ST from picking up at the end of the cycle. Relay OM however will remain picked up and the apparatus will complete the cycle, which will be terminated as above described except that relay O ST will remain released and will complete the pick-up cirout already traced for relay IS when relay OM releases. Relay IS will thereforepick up, and upon the closing of back contact Bl of contact T3P at the end of the cycle, assuming the lever contacts Al to be also closed, relay S'IPwill be 7 reenergized to initiate a new cycle of operation. As already mentioned, the selector systemof I Fig- 3 is free to be operated at any time, andrelay F of Fig. 1A is picked up for the duration of each selector code, disconnecting. themessage line bate tery. 8! from line wires :1; and z and also disconnecting terminal B of the local source from wire. 33. If relay F is picked u when the C. T. C. sys- My apparatus also includes a hand stepping switch HS by means of which the stepping operations may be manually controlled for observation or, test purposes. Normally switch HS occupies alower position as shown but ifswitch'HS is moved to its center position and a cycle of 0 3- eration is there initiated, it will be stopped with the stepping line open and with the apparatus in a condition ready to begin the first step, but with the circuit for relay Tl or T2 held open at contact 2. The first line closed period may now be initiated by moving HS to its upper position, in

which contact 2 completes the pick-up circuit for Tl or T2 and contact I completes a holdingcir cuit for relay Tl or T2 over its contact C2, and

the operation will be stopped with the'apparatus I on the line closed portion of the first step. If relay HS is then restored to its center position, re-

lay Tl or T2 releases and the operation stops with the steppingline open and the apparatus in con-- dition to transmit the second step. It will be seen that a different pick-upcircuit for r'elay Tl or T2 is closed by contact 2 over the contacts B6 and B4 of the stepping relays each time switch HS is moved to the upper position, and the energized relayTl or T2 is' released each time switch HS is returned to the center'position, while if' switch HS is restored to the lower position after the transmission of any number of steps in this" manner, the remaining'steps of the cycle will be transmitted automatically in the manner here-1" inbefore described.

Although I have herein shown and described butone form of my invention, it is understood that various changes and modifications may be made therein within the'scope of the appended claims without departing from the spirit and scope of my invention.'

Having thus described my invention; what -I claim IS:

1. In a remote control system, an oflice' and a plurality'ofjstation'sconnected by two line Wires, a polar relay at each station bridged across said line wires, a first line channel including said relays, said line wires inseries, and a sourceoi 7 current bridged'across said 'line wires at said ofiice, stepping line relays connected between said line channel including said stepping line relays,

-line wires and ground at each station,'a second said-line Wires in multiple, and a second source of current connected between said line wires and ground. at said office, transmitting means at said and source of current to the line wires to deliver fice for reversingth e polarity of the current supplied to said first line cha nel to a e saidpolar ofiice. for controlling the connection of said sec-1 at each station controlled over said second line channel by the stepping line relays and selectively responsive to said codes provided the polar relayat such station is reversed but requiring such= polar relay to be in its normal position to initiate its response to a code.

2. In aremote control system, an ofiice and a station connected by two line wires, a message line channel including said line wires and a source of current bridged across said line wires at said ofiice, a message line relay at said oifice responsive to variations in the current delivered to. said message line channel from said source, a stepping line relay connected between said line wires and ground at said station, a stepping line channel including said stepping line relay, said line wires 'anda second source or current connected between said line wires and ground at said office, a transmitter relay at said ofiice for controlling the connection of said second source of current to the line wires to transmit impulses from the ofilce to the station over said stepping line channel to repeatedly operate said stepping line relay, stepby-step means at theofiice and station operable respectively by said transmitter relay. and by said stepping line relay one step for each operation of said transmitter relay, means controlled by the step-by-step means at the station for connecting said line wires together on selected steps to transmit current variations from the station to the oflice over said message line channel to operate said message; line-relay, and indication means controlled by the step-by-step means at the office in accordance with the condition of said message line relay on said selected steps.

3. In a remote control system, an ofiice and a station connected by two line wires, a message line channel including said line wires and a source of current bridged across said line Wires at the oifice, a line relay at the oilice-of the stick polar pe ope e t a eve se o t n in r po s n an increase in the current delivered to said message line channel from said source, a stepping line channel including said two line wires, stepby-step means at the ofiice operable through a series of steps, means including a second source of current for delivering a series of impulses to said stepping line channel one for each operation of the ofiice step-by-step means, step-by-step means at said station controlled over said stepping line channel and operable by said impulses in unison with said ofiice step-by-step means, means for locally operating said line relay to normal just prior to each operation of said ofiice steptosaidrnessageline channel from said source, step-by-step means at the ofiice and station openable through a series of steps, including one step for each said device, a stepping line channel in.- cluding said two line wires, means including a second source of current for delivering a series of impulses to said stepping line ohannel one for each operation of the ofiice step-.by-step means,

step-by-step means at said station controlled over,

said stepping line channel and operable by said impulses in unison with said office step-by-step.

means, means for locally operating said office line, relay to normal just prior to each operation of said oflice step-.by-step means, means controlled by said station step-.byestep means on each step of said series of impulses delivered over said step.- ping line channel for preparing a shunt path adapted to connect said line wires together to.

momentarily increase the current delivered to said message line channel to reverse said line relay, each such path prepared by the step-by-step means being closed or left, open dependentupon the condition of the movable device associated with the corresponding step, and means. controlled by the ofiice step-by-step means for operating each indication relay to normalor reverse according to the position of the line relay on the corresponding step. t

5. In a remote control system, an ,ofiice and a plurality of stations connected by linewires, means at said office for transmitting different codes of impulses of selected relative polar ty over said line wires, each including a combination of impulses constituting a station code call, a series of stepping relays at said station, a cire cuit for at times energizing the f rst stepping relay of each series, circuits for energizing a plurality or" said stepping-relays at; a particular station one at a time in order, each in response to a difierent impulse but only if the relative polarity of such impulse is in accordance with the code call for that'station, the energization of each relay of said plurality being also dependent-upon h n gi zation of the next. p eced n relay of the same series, circuits effective only if the last relay of said plurality becomes energized for by-step means, means controlled by the station step-by-step means for connecting said line wires together on selected steps of said series to increase the current delivered to said message line channel to reverse said line relay, and indication means at the office controlled in accordance with the condition of said line relay on each of a plurality of steps of said series.

4. In a remote control system, an ofiice and'a station connected by two line wires, a series of movable devices at the station, an indication relay at the office for each said device, means for controlling each indication relay in accordance with the condition of the corresponding device, comprising a message line channel including said line wires and source of current bridged across said line wires at the ofiice, a line relay of the stick polar type operable to a reverse position in response to an increase in the current delivered again energizing the relays at said particular station one at a time in order through a second cycle in response to the succeeding impulses of the code but regardless of the polarity, a plurality oi movable devices and circuits controlled by said stepping relays during their second cycle of operation for successively controlling said movable devices one at a time in order in accordance with the relative polarity of the corresponding impulses.

6. In a remote control system, an office and a plurality of stations connected by line wires, means at said oifice for transmitting different codes of impulses of selected relative polarity over said line wires, each including a combination of impulses constituting a station code call, a series of stepping relays at said station, a circuit for at times energizing the first stepping relay of each series, circuits for energizing a plurality of said stepping relays at a particular station one at a time in order, each in response to a different impulse but only if the relative polarity of such impulse is in accordance with the code call for that station, the energization of each relay of said plurality being also dependent upon the energization of the next preceeding relay of the same series, a circuit controlled by the last relay of said plurality when energized for rendering the first stepping relay responsive to the next 7. In a remote controlsystem, an office and a plurality of stations connected by line wires, a. first. source of current bridged across said linewires at the oifice, a cycle marking relay of the; stick polar type bridged across the line wires at each station, step-by-step means at the ofiice operable through a series of steps, means including a second source of current for delivering a series 'of impulses to said line wires, one for each operation of the oflice step-by-step means, and for reversing the connections of said first source of current whereby the cycle marking relay at each station is reversed for the duration of said series of impulses, and step-by-step means at each station adapted to respond to said series of impulses but only if the cycle marking relay at such station is initially in its normal position and is then reversed for the duration of said series of impulses.

8. In a remote control system, an office and a plurality of stations connected by line wires, a series of stepping relays, a series of connector relays, including one for each station, and a starting relay, all at the office, a series of stepping relays at'each station, means efiective when said starting relay is operated for energizing said connector relays only one at a time in a fixed order and for operating said oifice stepping relays one at a time in order during the period of energization of each connector relay, means controlled by said oflice stepping relays for delivering a series of impulses to said line wires including one im pulse for each stepping relay, means controlled'by the connector relay then energized for controlling the relative polarity of certain of said impulses to form a distinctive code call characteristic of the corresponding station, means controlled over said line wires for operating the stepping relays at each station in response to such impulses but only if the relative polarity of said certain impulses is in accordance with the code call for that station, and means for operating said starting relay.

9. In a remote control system, an ofiice and a plurality of stations connected by line wires, a series of stepping relays, a series of connector relays, including one for each station, and a series of starting relays, all at the office, a plurality of movable devices at each station, means efiective when said starting relay is operated for energizing said connector relays only one at a time in a fixed order and for operating said stepping relays one at a time in order during the period of energization of each connector relay, means controlled by said stepping relays for delivering to said line wires a series of impulses one for each stepping relay having a relative polarity determined by the connector relay then energized, each series including a combination of impulses constituting a code call for the station with which such connector relay is associated, means at each station controlled over said line wires and selectively responsive to the corresponding code call, indication means controlled by each connector relay for indicating the condition of the movable devices at the corresponding station, means at' each station responsive to the received impulses and rendered efiective upon receipt of the corresponding code call for controlling the condition of said line wires to operate such indication means in accordance with the condition of the corresponding movable devices, and means at each station for controlling the condition of said line wires to operate said starting relay.

ALFRED B. MILLER

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