US2416699A - Station selector system - Google Patents

Description

March 4, 1947. s KWKEAD 2,416,699-

STATION SELECTOR SYSTEM Filed Dec. 8, 1942 3 Sheets-Sheet l R1714 S. KIN/(54D HIS ADM/N/STRAT/P/X Ba Q ATTORNEY s. KIN/(5A0 DECEASED Patented Mar. 4, 1947 a STATION SELECTORSYSTEM Fullerton S. Kinkead, deceased, late of New York, N. Y., by Rita Smith Kinkead, administratrix, Trudeau, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation ofNew York Application December 8, 1942,'Serial.'No. 468,210

22 Claims.

This invention relates to telegraph apparatus and systems and particularly to a station selector system for placing two or more of a plurality of stations in a telegraph system in intercommunicative condition under the control of any one of the stations.

The invention represents an improvement over station selector systems heretofore known and particularly of the type shown in Patent 2;152,01,0 granted March 28, 1939, to W. J. Zenner.

According to the disclosure of the Zenner patent each of a plurality of stations on a telegraph line is provided with a key for opening the line circuit for a predetermined minimum interval of time and each station responds to the opening of the line circuit by the starting of the operating motor of the printing telegraph set at that station. The attendant at the station at which the motor starting function was initiated then transmits the call signal of the calling station which is recorded at all of the stations andwhich is effective at the calling station to conditionthe motor starting apparatus to rema n operated-and thereafter transmits the call signal or signals of the called station or stations, which are recorded at all stations and which condition the motor starting apparatus 'toremain operated at the respective called stations. Thereafter the attendant transmits a common disabl ng signal which is efiective at all uncalled stations to shut-down the operating motors and to disable the transmitters and the call initiating line circuit keys.

'At the conclusion of message transmission between the stations which had been conditioned to participate in such transmission the operator at any of the participating stations again operates the line opening key, the efiect of which is to start the operating motors atall of'the disqualified stations in the system, those in the participating stations-remaining in operation. Thereafter the operator transmits a shutting down-code.

signal which is effective at all stations in the sys-- tem to open the energizing circuits for their .operating motors, thus shutting down .all of ,the stations and restoring them to initial .condition.

An object ,of the present invention is to provide a. station selector system :in which exclusion of stations from participation in message transmission is accomplished by suppression of print- 2 ing at such stations, the stations otherwise being in operative condition.

Another object of the invention is to provide a station selector system in which all stations are normally in operating condition but with printing suppressed and the conditioning of selected stationsto participate in mes-sage transmission is accomplishedby direct signal responsive disablement of the printing suppressi nmechaniSm.

Another object of the invention is to restore participating stations at the conclusion of message transmission by the direct signal responsive reenablementof the printing suppression mechanism at those stations.

Another object of the invention'is to render uncalled stations unresponsive to station calling signals during message transmission between stations which have been qualified to participate.

The invention features an arrangement whereby all stations in the system may be placed in condition to participate'in message transmission in response to the transmission of a common'calling code signal differing from the-selective calling signal of each station The invention also features an arrangement for suppressing a function, the performance of which at disqualified stations maybe objectioncalled stations and assuring privacy.

The invention contemplates the employment at each station .inthelsystem of a printing telegraph receiving recorder which may be of the type shown in Patent.1,9.04,164, granted April 18., .1933, to S. Morton .et a1. Theinvention also contemplates that each of the .printing 1telegr aph recorder instrumentalities shall include a printing suppression mechanism and may include ,a switching contact mechanism such as "those shown in co-pending application, Serial No. 398,055, filedJJune 14'f1-941, by"W. Y. Lang, new

Patent =N0.'2,318,'168, grantd'May 4, 19,43. The

disclosures of the Morton et al. patent and of the Lang application are incorporated herein by reference as part of the present specification.

In accordance with the preferredembodiment of the invention, a magnet, which upon being energized disables the printing mechanism, is normally energized when the system is in the idle operative condition, through parallel circuits controlled by two relays. The idle operative condition refers to the condition under which the printer operating motors at all stations are in operation and the printing suppression mechanism is in the effective condition to suppress printing. One of the relays is operable in response to the calling code signal of the particular station and to the group or universal calling code signal and upon energization interrupts one of the two parallel circuits. A second relay is energizable in response to a code signal common to all stations and this relayis effective to open 4 description to be interpreted in the light of the accompanying drawings wherein:

Fig. 1 is a combined schematic perspective view and circuit diagram of a portion of a telegraph printer as exemplified in the Morton et al. atent with the addition thereto of printing suppression mechanism and switching mechanism generally in accordance with the disclosure of the Lang application;

Fig. 2 is a schematic circuit view showing the station selecting-circuits, and the'circuits in Figs. 1 and 2 are complementary, the proper relationship being established when Fig. 2 is positioned below Fig. 1;

: sion mechanism;

Fig. 4 is a fragmentary plan view showing switching contact operating mechanism; and

the second parallel circuit for the print suppres iv sion magnet, thus releasing that magnet and dis- I abling the print suppression mechanism when both relays are energized. Both of these relays have holding circuits whereby they are held upon being-energized. At unselected stations only the second of the two relays becomes energized and only one of the parallel energizing circuits for the printing suppression magnet is interrupted,'so that the magnet remains energized and prevents the printing telegraph recorder from printing in response to signals thereafter received. The second of the two relays interrupts the energizing circuit for the first, so that at unselected stations the first or selectively operable relay will not become energized in response tosignals occurring in message transmission between two or more stations which have been qualified to participate in such transmission. At the conclusion of message transmission a code signal common to all stations on the system and preceded by the figure shift signal effects the interruption of the holding circuit for the one relay which is energized at unqualified stations and for the two relays which areenergized at qualified stations, thus restoring the energizing circuit for the printing suppression magnet at all stations, which re resents restoration to the idle operative condition. g I 1 The power supply circuits for the operating motors of the printer-are controlled by systems of relays which are set in operation to effect the closure of the motor circuit in response to placing of the telegraph signaling channel in the spacing condition for aninterval which is relatively long in comparison with the interval oc. cupied by a permutation code signal combination. The relay which controls themotor circuit has a holding circuit which is effective tohold the relay energized so that once the motor is started further abnormally long spacing signals on the telegraph channel will not affect the op-' mechanism has been activated atallstations, to;

interrupt the holding circuit for the motor control relay whereby the motor operating circuit is: interrupted at each station and the motor ,is;

stopped. 7 1 1 V a For a complete understanding of the invention.

reference maybe had to the following detailed Fig. 5 is an elevational view partly in section showing a function suppression mechanism.

Referring now to the drawings and particular- 1y to Fig. 3, the reference numeral N indicates a selector magnet, the armature 12 of which is carried by a selector lever l3 pivoted at M. As is fullydisclosed in the Morton et al. patent, the selector lever l3 controls a plurality of sword levers it which are individually articulated to bell cranks I] pivoted at 58 and individually rocked in counter-clockwise direction once in each receiving cycle by cams I9, one of which is shown in Fig.3, included in a receiving selector cam assembly mounted on and frictionally driven by a power driven shaft 2!. their bell crank levers H, the sword levers l6 are rocked into extreme clockwise or counter-clockwise. position depending-upon the position of selector lever 13 as determined by selector magnet l l and when they are shifted rightwardly by their bell cranks I! as the bell cranks are restored to extreme clockwise position by their individual springs 22, the sword levers rock associated T-levers 23 into extreme clockwise or counterclockwise position depending upon the rotative position into which they have been rocked under the control of the selector magnet. The T-levers 23 are articulated by means of disc and slot connections to individual selector vanes that are pivotally supported at their opposite ends by trunportion 29 which straddles the edge of the selec-- tor vane and remains in engagement with the vane while moving along its edge as the typebasket'moves forcharacter spacing and carriage return operations. The typebasket pivotally supports a plurality'of type bars 3i which have rack and pinion-connections with individual selectable V pull bars 32, the foremost ends of which are disbasket; .Each of the'pull bars 32 is provided with posed above and in close proximity to the'code' bars 21. The pull bars '32 are normally supported with their foremost ends just out of engagement with the code bars 21 byengagement of a sloping cam surface on the lower edge of each pull bar 32 with a blade 33c'arried by 'a reciprocable printing bail 34 which ismounted on the type- Upon being retracted by a -hook '35 at the upper end of the sloping cam sur= face so that when the printing bail 34 is reciprocated rightwardly as viewed in Fig. 3 and the right-hand ends of thepull bars move downwardly into engagement with the code bars 21, any pull bar which finds an alignment of notches presented to it by the code bars will move still farther downwardly at it right-hand end into the alignment of notches, bringing its hook 35 into the path of blade 33 of printing bail- 34, so that as the bail continues to be moved farther to the right, blade 33 will engage the selected pull bar and reciprocate it rightwardly, thus rocking the associated typebar 3| in counter-clockwise direction to bring its type carrying face into printing engagement with paper-carriedby a printing platen 36. v f

Printing bail 34 is provided with a depending stud 31 which rotatably supports a roller 38-disposed between a pair of blades 39 supported at the upper end of a printing bail operating arm 4|. The roller 38 and blades 39 provide for operative engagement between printing bail 34 and operating arm 4| throughout the path of travel of the typebasket by which printing bail 34 is supported. Operating arm 4|, which is supported on rock shaft 42, is urged in clockwise direction by a tension spring 43 which supplies the power for operating the arm 4| and thus the bail 34. A printing cam 44 which is included in a main cam assembly carried by the shaft 2| is engaged by a roller 46 (Fig. 1) carried by a pivoted lever 41, the upper end of which supports an abutment screw 48 which engages the right-hand side of the right-hand one of the operating arm blades 39 as viewed in Fig. 3. The cam 44 operates through lever 4'! to restore operating arm 4| to extreme counter-clockwise position and to hold it in that position in the idle condition of, the apparatus. When the main cam assembly is released for rotation by the receiving selector cam.

assembly a sharp drop off of the cam 44 permits the spring 43 to rock printing bail operating arm 4| sharply in clockwise direction to effect a printing operation, and during the remainder of the cycle of the main cam assembly the cam 44 restores operating arm 4| to extreme counter-clockwise position which in turn restores bail 34 to its unoperated position.

Although only one printing bail operating arm 4| ha been referred to in the foregoing paragraph, it will beunderstood that there are at least two such arms located near the ends of rock shaft 42 and that there may be others intermediate those two. Associated with the end ones of the arms 4| are brackets 5| (Fig. 1) interconnected by a bar 52 and supporting the ends of a function selection control rod 53 which extends parallel to the axes of the selector vanes 24. At

the rear of the vanes 24 a plurality of selectable.

function levers, such as the levers 56 and 51, are pivotally mounted ona rod 58. Each of the selectable function levers is provided with two spaced upwardly extending arms. The arm of the selectable function lever that is nearest to the rear edge of the selector vanes is provided with permutation code combinations of lugs with which the selector vanes presented in certain positions interfere. When the selector vanes corresponding to all of the lugs of a selectable function lever are in proper position to select this lever, the function lever is not blocked but is free to rock in clockwise direction as viewed in Fig. 3. However, the rocking of the function lever is norm l y P evented, by he 52 (Fig. 12.1 The 5 cooperates with a cam portion of the rear armiof each of the function levers. When the printing bail operating arm 4| is operated by spring 43, the

rod 53 is moved downwardly along the cam s'ur- I face of the rear arm of each function lever and permits the function levers to rock in clockwise direction as viewed in Fig. 3 to test the setting of the selector vanes 24. Any function lever which finds no selector vane blocking its lugs will be rocked in clockwise direction by its associated spring 59"to perform or initiate its assigned function as the case may be. The printing bail bar 52 carries an upturned flange 55 which overlies the tops of the rear arms of selectable function levers 56 and 51 and which moves down into engagement with the top of the rear arm of either of those levers when they are selected, the function of the flange being to block the printing bail mechanism after it has operated far enough to permit the selection of the function lever, in order to suppress operation of any pull bar '32 that may also be selected, and also the carriage spacing mechanism. 7

Those functions which require more power for their performance than the springs 59. can

' supply, or the performance of which should be prolonged over a greater interval than that involved in the rocking of its function lever to the extreme clockwise position as viewed in Fig. 3, are performed by a function bail 6| supported by operating arms 62 journaled on rock shaft 42. Associated withone of the function bail operating arms is a cam follower lever arm 63 which supports at its free end a roller 64 which engages cam 66 included in the main cam assembly. When the main cam assembly is rotated, the function bail operating arms 62 are positively rocked slightly in counter-clockwise direction by spring 61 under the control of cam 65, then in clockwise direction as viewed in Fig. 3 by cam 66 andthereafter the function bail 6| is restored to normal, which is short of extreme counter-clockwise position, by spring 51. The manner in which function bail 6| operates function performing members will be described hereinafter.

Referring now to Figs; 1 and 4, it will be noted that a cradle 7| consisting of a flat plate 12 and parallel arms 73 is pivotally supported by trun nions 74 which engage the arms 13 near the inner ends thereof. Extending between and supported by the'outer ends of arms 13 is a' pivot. rod 16 which pivotally supports a plurality of bell cranks 11 in alignment with the marking position of fingers i8 integral with and extending rightwardly from the right-hand ends of the selector vanes 24. The, plate 12 of cradle supports a plurality of pairs of normally open electrical contact springs 79, there being a. pair of electrical contacts assigned to and aligned with the other arm of each of the bell cranks Tl.

Cradle 1| is provided with an operating arm 8| which is connected by spring 82 with the free end of a laterally extending arm 83 of a push bar 84. Push bar 84 is mounted for reciprocable. movement leftwardly as viewed in Fig. 3, by pins 8% which pass through slots. 81 in the push bar 84. I Near its foremost end the push bar 84 is provided with a notch in its upper edge which-pro vides a shoulder 89 disposed slightly to the rear of the position occupied by a blade 9| carried by function bail 6| when the bail is in its unoper-' ated position. The push bar 84 is urged to its" extreme forward position (rightward position as. viewed in Fig. 3) by a tension spring 92 which returnsthe push bar to its normal position after each operation of the pushbar leftwardly, by function bail blade9 I. Each time that the push bar is reciprocated leftwardly as viewed in Figs. 1 and 3, it imparts through spring 82 clockwise movement to cradle 'II as viewed in Figs. 1 and 4. An extension 80 of cradle operatingarm 8| par-J allels spring 32 and is held by spring 82 in abutment with the end of push bar arm 83, for the purpose of stabilizing cradle II and the motion thereof under the control of push bar 94. The

.pairs of contact springs 19 carried by the cradle I I are moved in an arcuate path about the trunnions I I as an axis and since the bell cranks are held in engagement with their respective contact springs by tension springs 15, which exert insufiicient tension to close the springs, the bell cranks -II are moved arcuately in clockwise direction about the axis of trunnions 14. 'After' the bell cranks 71 have been rocked through a short angular distance, those of the selector vanes 24 that are then presented in the marking position will block by means of their fingers I8 further movement of the bell cranks 11 associated therewith so that the bell cranks will be arrested. As the cradle 'II continues to move to its fully operated position with certain of thebell cranks 'II blocked by the selector vanes 24, the corresponding electrical contact springs yield in order to be further moved while their bell cranks are blocked and in so yielding the contacts are closed.

numeral TI withthe five selector vanes desig nated by the common reference numeral 24. The provision of five selector vanes presupposes the operation of the printer on a five-unit permutation code which is the commonly used code for telegraph printers. The sixth set of contacts 93 cooperatewith a sixth bell crank 94 which in turn co-operates with a sixth vane 95." The sixth vane 96, as is fully disclosed in theiMorton'et a1. patent,-is the shift and ,unshift vane, and this vane is operated by the shift and unshift mechanism which also shifts the platen to letter or V figure printing positions with respect to the type bars3l. When the platen is in the letter printing'position the sixth vane occupies the position shown in Fig. 3, namely, the extreme clockwise position. 'When the platen is shifted to the figure printing position, the'sixth vane is rocked into its extreme counter-clockwise position and it is then in blocking relation to the bell crank 94' which controls the sixth set of contact springs- 93. As is disclosed in the; Morton et al. patent.

the function of the sixth vane 96 is to block certain of the function levers, exemplified by the levers 56 and 51in Fig. 1, against selective response. to the five selector vanes 24. By this means. certain of the functions may be initiated or performed only when the printer'is in the figure shift condition and others maybe selected and performed only when theprinter is in the unshift or letters condition. The provision of the v sixthlset of electrical contact springs 93 operable only when the sixth vane 96 isinthe figuresshi ft positionprovides for the performance of .an elejc-r trical operation only when'the printer is in the figure shift condition as will be described latery This corresponds to the blocking out of a func+ pivoted at I". Lever H6 is biased in counterclockwise direction as viewed in Figs. 1 and 3 by in Fig. 3, and with a pointed or tapered end Lever H9 is normally maintained in'a predetermined position with respect to magnet-controlled lever I I6 by means of a tension spring I22. When magnet H2 is deenergized, spring H8 holds lever IIB against a, stop I23 with shoulder I2I of lever H9 out of latching orblocking relation to the print bail operating blade 39. When magnet I I2 becomes energized, it rocks lever I IS in clockwise direction to bring shoulder I2I of lever H9 into a position below the upper edge of the rearmost blade 39. If print bail operating arm II is at this time in its normal or unoperated position, the shoulder I2I of lever II9 will be disposed in the path of blade 39 so as to prevent the movement of the printing bail to its operated position which, it should be remembered, is permissive since the bail is operated by spring 43 and is-restored by cam 9'4. If at the time the magnet II2 becomes energized, the printing bail is partially or fully operated, some portion of the tapered or pointed.

end of the lever H9 will drop into engagement with the top of blade 39 and when the printing bail is restored to its normal or unoperated position, the lever II9 will be cammed in counterclockwise direction by the cooperation of its remains in blocking relation to the print bail' operatingmechanism so that the bail cannot be operated to effect printing. It should be. noted that the full operating stroke of the printing bail 34 is not blocked but only that it is blocked sufficiently short of its. full stroke to prevent its blade33 from engaging the hook 35 on any selectable pull bar 32 that may be selected. The

partial stroke of the print bail operating arm II that is permitted before blade 39 comes into engagement with shoulder I2I of blocking lever H9 is sufficient to permit rod 53 to move downwardly' along the cam surfaces of the rear (lefthand) arms of theselectable function levers, such as 56 and 51, to permit the function levers to test the setting of the selector vanes 24 and to permit the selection of any such function lever which is not blocked by the selector vanes.

As shown in Fig. 1, the selectable function lever 56 has a rearwardly extending arm I3I upon which rests the foremost end of a function push bar I 32. At its remote end push bar pivotally supported by the depending arm I33 of a bell crank which is shown only fragmentarily. The bell crank represented by arm I33 is operable to effect step-by-step line feeding rotation of the p1aten36 byoperation of a line feed pawl in'a manner fully disclosed in the Morton et al.patent.

On its upper edge the line feed'push bar I32 is. providedwitha lug I 34 which is lifted into the- 9 path of function bail blade 9| upon lifting of the foremost end of push'bar I32 byfunction lever 56 as the function lever rocks inclockwis'e direction as viewed in Fig. 1 upon being selected by the selector vanes 24. When the function bail arm 62 is rocked in clockwise direction as viewed in Fig. 1 by function cam 65 following-the lifting of the foremost end of push bar I32, the push bar is reciprocated rearwardly of the printer (leftwardly as viewed in Fig. 1) to rock bell crank lever arm I33 in clockwise directio'n by which operation platen 36 is rotated one step, and "upon the return of function bail arm 62' by spring" 6T! under the control of cam- 66, push bar I 32" "is restored to normal position by spring I33, the lug I34 on the push bar I32 being lowered out of the pathof function bail blade 3! by the upper rearwardly extending ar'm I31 of selectable function lever 56 when that lever is restored to.

unselected position. v i

A latching bell 'crank'for preventing the lifting of the foremost end of push bar I32 into'cooperative relation'with thefunction bail blade 9| is indicated by the reference numeral "I38. Bell crank I38 is biased-in clockwise directionby tension spring I39 seeking to move the latching hook I4! of bell crank I38 out of" blocking relation to push bar I32. Bellgrank I38 has a laterally extending arm I42 which serves as the armature for an electromagnet I43. When the electromagnet is energized, hook It! of latching bell crank I38 is presented in blocking relation to-push bar I32 so that its foremost end carrnot'be lifted by the rearwardly extending arm I3I of selectable function lever 56 and thus the lug I34 cannot be brought into the path of function bail blade GI. When push an I32 i blocked by latching bell crank I38, the push bar in turn prevents the movement of selectable function lever 56 into selected position. Since the rocking offunction lever 56 into selected position is permissive under the control of bar 53 carried'by the printing bail mechanism, the blocking of push bar I32 against upward rotation is permissible. The function of latching bell crank I 38 is 'to suppress the line feed function under conditions which will be described.

hereinafter. I V e A station selector system in accordance with the present invention is shown in Fig. Z Qthree stations A, B and C being shownf'A closed includingsignaling: battery 232 extends through selector magnet I I transmission circuit 23 I transmitting contacts 203, break 'key 234 and a relay 2% at station A, selector magnet transmitting contacts 2138, break key 239"and a relay corresponding to the relay 2% at station B, and

lay 2533 at station C. The closed signaling circuit may include other stations similar to the stations A, B and" C. The printing telegraph receiving recorder for the station A controlled by selector magnet ii is shown in Fig l and certain'electrical conductors which will be identifled hereinafter extend between Fig. 1 and Fig. 2. At stations B and C the selector magnets 20'! t rin f and 2II are intended to symbolize printers.

With current flowing in the closed transmis'*' sion circuit, the relay'2ll5 at station A and'the corresponding relays at stations 13 and C will be energized. At its single'armature and back contact, relay 2138 holds open the circuit of a slow operating relay 256, the conductive path being traced from one terminal of battery 2IIto the 10' back contact of relay 206 and from the other terminal of battery 2I I through conductor 2| 8, normallyclosed contacts 2| 9 controlled byrelay 22I" which at this time is released, conductor 222 and winding of relay '2IIi to the armature of relay'ZilB. Upon the opening of the break key at any one of the stations, such as the key "204 at station A, the circuitof relay 236 andof all corresponding relays at the other station will be interrupted and thoserelays will be released. Relay 2% completes the energizing circuitifor relay 2H2" which becomes energized after an interval which is longer than any spacing "interval normally encountered in telegraph message transmission,"the purposein providing that relay 2I6'shall be slow operating is to prevent its operation in response toany fortuitousrelea'ses of relay 206 such-as might be due to .hit's upon the telegraph circuit 201. Preferably relay 216 requires'an interval'of the orderof three seconds'to operate. J

Upon the operation of relay2i6 ground 'on'its front contact is connectedthrough its arma' ture and conductor 223, winding of relay 22'I to grounded battery; thus causing relay 22I toope'rate; "At its lower armature and front'cont'act relay" '2'2I' connects ground over conductor 224.

and winding of a: relay226' to grounded battery-.' Relay 226 becomes energizedand extends con nections from battery 2|! through its two' arinatures and front contacts to the operating motor 221 for transmitting contacts'203 and for the" receiving printer mechanism shown'in' Fig; 1: At the upper-armature of relay 22'I groundconnection is extended through the front contact, the

.make-before-break contacts of a relay 228, '.COIl-' ductor 2'29-and conductor 223 through: the winding of relay 22I to groundedbattery thuses'tablishing a holding circuit for the relay. The up:

per armature of relay 22I opens the-oontacts'2'I9' through a mechanical connection between con-;

tacts 2I9 andthe upper front contact. thus open-" energized upon-the reclosure' of break key .204

or other break key in the system'the opening of a which released the relay 206-; By the foregoing operations the printer an'd'transmitter operating motors at all stations have been set in operation so that thesystem has been changed from ashutdown condition tothe idle active condition with the printers at all stations capable of responding to signals.

The selection of-station A forparticipation in signal transmission is controlled byrelay 24h lhis relay isnormally deenergized and acirCuit; is traced from ground through" its outer upperarmature andbackc'ontact and in parallel therewith from ground through the outer upper ar--.

mature andback contact-of a relay- 242, which-- is alsodeenergized at this time, through conductor Electroblade 9L.

As contacts 2I9 are opened, contacts.

1 1 .The operation of relay 24! is controlled by the selector vane sensing. contacts 12. A battery I48 having one terminal grounded ha its other ter-- minal connected to one spring of each of the five pairs of contact springs!!! and to one spring of the pair of contact springs 93. The other spring of each of the five pairs of contact springs 19 is connected by one of five conductors 244 to one terminal of an individual one of five relays 246, the other terminal of which is connected to ground. The other spring of the pair of contact springs 93 is connected by conductor 24'! to one terminal of relay 248. The five relays 246 con I trol a fan circuit system of armatures and con tacts, the uppermost having a single armature operable between one front and one back contact whichare connected to two armatures of.

- will be understood that the fourth relay could have as-many as eight armatures each operating between a front and back contact and that the fifth relay may have sixteen armatures operat in between. a front and a back contact to provide a maximum of thirty-two selective paths, The armature of the uppermost of the relays 246 is connected by conductor 25! extending into Fig. 1 to one contact spring of a pair of normally open contacts !5!, the other of which is connected to ground. Contacts !5! are mounted to be engaged and operated by push bar 84 which operates cradle 1!. The contacts !5! are disposed in such relation to the rearmost end of push bar 84 that the are not closed until after cradle I! has been operated to close those of the contacts 19 and 93,

the operating bell cranks of which are blocked by vanes 24 in the marking position or vane 96 in the figure shift position.

For the purpose of illustrating the selection of station A for participat ng in messa e tran mission, assume that station B transmits the selecting code combination for station A which will be assumed to be the code for the letter A. All of the stat ons in the syst m respond to the transmission of this code and position their selector vanes in correspondence with the code of the letter A'. Following the positioning of the vanes the main cam assemblyof each printer is operated. this including the cams 44 and 66. Cam 4 seeks +0 operate printipg bail 34 which is blocked at all stations. Cam'66 then operates the f nction bail bla e wh c reci rocates push bar-=84 toward contacts 5l.firstclosin certain of the contacts 12 in corr s ondence with'the setting of the selector vanes 24. and then closing the contacts I5!. The permutation code combinat on representin the letter A has im ulses armature and front contact of relay 246 which is now energized; inner armature and front contact of the second relay 246 which is also energized, innermost armature and back contactjof the third relay, innermost armature and back contact of the fourth relay, innermost armature and back contact of the fifth relay, Conductor 252, back contact and inner upper armature of relay 242 and winding of relay 24! to grounded battery 253. Relay 24! completes its holding circuit through the front contact and inner lower armature, conductor 254 and back contact and armature of relay 248 to ground. At its outer upper armature relay 24! removes one of the ground connections from conductor 243 but electromagnets H2 and !43 in Fig. 1 remain ener gized to the ground on the outer upper armature of relay 242. At its inner upper armature relay 24! completes a circuit from ground over cone ductor 256 and lamp 255 to grounded battery 258 andthe lamp 255 lights to indicate that stationA is being conditioned for participation in message transmission, such conditioning bein by remote control. At no other station does the relay corresponding to relay 24! become operated, because at no other station is such relay operable over a fan circuit path completed in response to the code combination for the letter A.

It will be noted that relay 24! may also be energized from ground through normally open key 251, lower armature and back contact of relay 24fland conductor 259. Key 251 and the circuit which it completes enables the selecting relay 24! or its corresponding relay at other stations to be energized by direct manual control 7 such as at a call initiating station so that it is not necessary for the calling operator to trans x mit the selecting code of his own station in order to prepare that station to be conditioned to participate in the message transmission. It will system, being completed when the first and third v of the relays 246 are deenergized and the second, fourth and fifth relays are energized, and rep-- resents a group selection of all stations by the transmission of a common calling code whereby it is unnecessary to transmit in succession the calling codes of all of the stations when it is clesired to transmit to them n a group or broadcast basis.

.Following the transmission of the code which effected the operation of relay 24!, the callingoperator transmits a code combination which effects the selection, at all stations including the calling station. of the selectable function lever V 51. This function lever has a forwardly extending arm I52 which momentarily closes normally open contacts I53. connected to ground and the other is connected over conductor 26! extending into Fig. 2 through the winding of relay 242 to grounded battery 263.

Relay 242 becomes energized and completes itsholding circuit through the front contact andinner lower armature to ground through the back contact and armature of relay 248 in parallel with the holding circuit for relay 24 One of the contacts 5 3 is;

Selectable function lever 5'! at each station is responsive to the same code so that contacts I53 at st'ationxA and the contacts corresponding thereto at all other stations close, and relay 242 at station A and the relays corresponding thereto at all other stations become energized and held.

At its outer upper armature the relay 242 disconnects ground from conductor 243thus opening the energizing circuit for the electromagnets H2 and M3 at the calling station and also at the called station A, so that the printers at those stations are conditioned for full normal operation of their printing bails and the suppression of the line feed function is removed. At. uncalled sta-' tions the magnets H2 and I43 are not released because the relays at those stations corresponding to the relay 2%! are not energized and one ground connection remains on conductor'243' at the uncalled stations. The outer upper armature of relay 2G2 completes the circuit of lamp 264 over conductor 28? to battery 258 so that the lamp 2% becomes lighted at all stations. The lighting of lamp 254 at uncalled stations indicates that the system is in operation for message transmission and that those stations have been excluded. Lamp 261i therefore is a busy lamp. At the calling and called stations both of the lamps 25%: and 2% are lighted, indicating that those stations have been selected forparticipation in message transmission and that the' magnets HE and I43 have been released byremoval of both ground connections. I

At the inner upper armature relay 242' interrupt-s the energizing path for relay 24 I, This has no effect at the calling and called'stations since relay 2d! and the corresponding relay at the calling station are held energized, but at the excluded stations it prevents the energization of the relay corresponding to the relay 2 in response to signals appearing in the message transmission which are identical'with the selective calling signals of the uncalled stations or in response to the signal which is identical with the group call ing signal. In this way 1e assignment of codes for calling stations individually or in a group does not diminish the number of codes available for message transmission. At the middle lower armature, relay M2 interrupts a conductive path. from the innermost front contact of the fifth re;

7 armature of relay E li has a back contact which is connected to the outer lower armature of relay.

42. The latter armature has a front contact which is connected through the winding of a relay 246 which is energizable to establish, at its and front contact, a shunt upper armature around transmitter 263 and break key 264. Relay 266 is energized when relay 2 H isunoperated and relay 222 is operated, which is the condition of an uncalled and disqualified station, andprevents an attendant at a disqualified station from interfering with transmission on the line, because the break key and the transmitter are short-cir cuited and are rendered incapable of opening the line circuit. At its lower armature the relay 240' interrupts the conductive path from key 251 "to the winding of relay 24!. Thus an attendant at an uncalled station cannot unauthorizedly' opcrate relay 2 to disable his print suppression mechanism and render his recording printer operatively responsive to signals on the line which are actuating selector magnet I I, and privacy is;

thereby assured. When relays 2M and 242 are both released, which is the idle condition, the

code signals. At the uncalled stations characters.

corresponding to the transmitted signals will not be printed although the selector magnets at those stations will respond to all signals and the selector vanes will be operated in correspondence with such signals, printing being suppressed by the magnet H2 and magnets at other stations corresponding thereto which are energized.

Character spacing will not occur at the excluded stations except in response to the spacing signal combination because normal spacing for successive characters occurs incident to the operation of the printing bail, as is fully disclosed in the Morton et al. patent, and with printing suppressed at the excluded stations spacing will also be suppressed. The spacing function will be performed at excluded stations corresponding to the few word spaces that will appear in the message material transmitted in each line of message material being recorded at the qualified stations, but the excluded stations will also respond to the. carriage return function and will restore the carriage to the beginning of line position before it has (advanced more than a few spaces from that position. The shift and unshift functions will also be performed at the excluded stations but these are idle operations since no message material is being recorded.

The latching of the line feed push bar at the exeluded stations prevents the performance of the line feed function at those stations and thus pre vents the advanceof paper past the printing line position-as the paper is line fed at the printers which are recording the message material transmitted. Were it not for the suppression of the" line feed function, it might be necessaryfor an attendant to back feed the platen manually at frequent intervals to prevent paper at those stations.

- At the conclusion of message transmission the system maybe restored to the idle active condition by transmission from any one of the participatin'g stations of the deactivate code signal; Since it has sometimes been the custom in' sta' tion sele'ctor'systems to employ as the deactivate or restoration signal a combination of. two permutation code signals one of which is the figure shift signal and the other is the signal corresponding to a character, such as the letter I-I, whereby the code for that letter may have the dual function,

in the unshift condition oftheapparatus, of selecting a station when printing is suppressed, and;

of effecting the printing of the letter H when printing is not suppressed, and when the printer is in the shift condition, for effecting restorationof the stations to the idle active condition.

Upon the transmission from any of the participating stations of the figure shift function, the

shift vane'96 at all stations will be operated to the wastage of viously stated, contacts 93 when closed extend a battery connection to relay 248 but this is not effective to complete the energizing circuit for relay 248 because the fan circuit path to which the lower terminal of relay 248 is connected; is not completed in response to the figure shift signal. Following the transmission of the figure shift signal, the code for the letter H will be transmitted. After the five vanes 24 have been positioned in accordance with this signal, push bar 84 will be operated to cause the rocking of cradle 1| and since the code for the letter H has impulses l, 2 and 4 of spacing nature and impulses 3 and 5 of marking nature, the third and fifth of the relays 246 will be energized to complete a conductive path from the armature of the first relay 246 through its back contact, the outer armature and back contact of the second relay 246, the outer armature and front contact of the third relay 246, the outerarmature and back contact of the fourth relay-246, and the outer armature and front contact of the fifth relay 246, winding of relay 248, conductor 241 and closed contacts 93 to battery I48. Upon the closure of contacts l5! by push bar 84 after it has operated contacts 12 and 93, the conductive path just traced willbe extended from the armatureof the first relay 246 over conductor 25! and contacts [5| to ground, thus energizing relay 248 momentarily. At its armature and back contact, relay 248 interrupts the holding circuit for relays 24! and 242, thus extinguishing lamps 255 and 264 and restoring the station selecting apparatus to normal at all stations.

At the close of the business day or whenever it is desired to restore the multistation telegraph system to the shut-down condition, this may be accomplished by the transmission from any one of the stations of a signal assigned to the performance of this function which may, for example, be the code corresponding to the letter Z. At all stations, the selector vanes are set in response to this signal to cause the first and fifth of. the relays 246 to be energized. When the contacts 'l5l are closed momentarily following the closure of the first and fifth pairs of contacts 12, a circuit may be traced from ground through closed contacts l5l, conductor 251, armature and leased during the time that relay 22: has been.

energized and which is a slow-operating relay as previously stated. With relay 22l released, the circuit of relay 226 is interrupted and this relay releases, thus opening the circuit of motor 22?. Contacts 23! open and remove the short circuit across the winding of relay 2% so that this relay is reinserted in the closed communication circuit and becomes energized to open the circuit of relay 2 l6. Contacts 2l9 reclose to prepare the energizing circuit for relay '2l6 which remains open at relay 296. Thus the apparatus is restored to the initialshut-down condition.

It is to be understood that the energizing circuitv for relay 242' could have been completed through a selectively prepared fan circuit path controlled by the relays 246 instead of through the contacts I53 operated by Selectable function levers 51. It will also be understood that select: able function levers could be employed in lieu of the relays 246 and the fan circuit paths for completing the energizing circuit of all of the selectively operable relays, these being the relays 24L 242, 228 and 248. In the case of the relay 248 which is to be operable only when the printer is in the figure shift condition, the selectable function lever for completing the energizing circuit of relay 248 may be blocked against selection bythe vane 95 when the vane is in the unshift position so that the selectable function lever could not be selected and operated until after the vane 96 had been operated to the figure shift condition in response to a shift signal. It would then not be necessary to include a fan circuit path in the energizing circuit of relay 248, as the selectable function lever would interpret the shift condition of the printer and the code, such as H for selecting the relay. Also the contacts front contact of the first relay 246, inner armature and back contact of the second relay 245, third armature and back contact counting from the left of the third relay 246, third armature and back contact counting from the left of the fourth relay 2G6, third armature and front contact counting from the left of the fifth relay 246, conductor 21! middle lowerarmature and back contact of relay 242, conductor 212 and winding of relay 228 to grounded battery 213. Relay 228 becomes energized over this circuit and as its armature engages its front contact completes its holding circuit to ground through the front con tact and upper armature of relay 221, after which the relay 228 interruptsthe holding circuit for rela 22L the contacts controlled by the armature of relay 228 being operable in make-beforebreak manner. As soon as the relay 22!, its holding circuit having been interrupted, releases its upper armature, the holding circuit for relay 228 is interrupted so that that-relay is released; Relay 228 does not become reenergized when its movable contact comes into engagement with'its fixed contact and before theiarmature becomes disengaged from the movable contact, because it could bereenergized only from the armature and front'contact of relay 2l6 which has been re- 93 would not be required. In fact the relay 248 could be omitted, substituting normally closed contacts for supplying ground for the holding circuits of relays 24! and 242, the contacts being operable by the function lever to open the holding circuits. The selectable function lever 51 represents a mechanical arrangement for integrating or interpreting a permutation code signal and the contacts 19 and relays 246 represent an electrical means for integrating or interpreting a permutation code signal. Either may be employed exclusively or a combination of both as indicated in Figs. 1 and 2 may be employed within the contemplation of the invention.

Although a single transmitter has been indicatedsymbolically at each station by a set of transmitting contacts, it is within the contemplation of the invention to provide keyboard transmitters or storage type transmitters, such as tape transmitters, or both, at any or all stations, and to transmit station selecting, station disqualifying and motor stopping signals, as Well as message signals, from any such transmitter. The Morton et a1. patent, hereinbefore identified, fully discloses how keyboard and tape transmitters may be provided and operated at a telegraph station having a receiving printer of the type shown in that patent, of which the printer shown in the present application is a modification.

Although a specific embodiment of the invention has been shown in the drawings and described in the foregoing specification, it will be understood that the invention is not limited to such specific embodiment but is capable of modification and rearrangement without departing emc e) from the spirit ofthe invention :and within-the scope of the appendedclaims.

:Whatis claimed is: :l. In a communication :system, a communication channel, aplurality of telegraph stations I associated with said channel, ;a printing telegraph recorder :at each station, Fmeans in ach recorder for :suppressingprinting :operation thereof, a relay at each station operable to'disable said suppressing :means, a second relay at each station operable to 'estop operation -or"-unoperated ones of said 'disablingarelays, :a plural-ity or signal responsive iselector elements in each of said recorders, a selectable 'member directly xresponsive to said selector elementsafar-controlling one of'said.relays,a plurality of setsaof electrical contacts controllable :by saidiselector 'elementsxin accordance with the signal responsive operation of :said element's, a plurality "of irelays controlled bysaid electrical vcontacts and means n'controlled by the last-mentioned "relays for selectively establishingian energizing vcircuitior thB'iOthBILQf the two first-mentioned relays.

.2. In 'a communication :system, arommu'nication channel, :a plurality :of tele'graph stations associated with said channel, a printing telegraph recorder at each station including .a signal responsive selector mechanism, a'printingmecha- .nism 'op'erableunder' the control of said selector mechanism an'd a-drivingmotor for both of said mechanisms, m'eans controlled by said channel independently :of said selector mechanism at each station for completing the ope'rating circuit of the motor, means in each recorder for suppressmeans controlled by the selector mechanism "at each station for disabling'said motor circuit "completing means, andmeans at each station controlled-bysaid selector mechanism forestopping operation of both of said disabling means.

3. In a communication system, a communication channel, a plurality of telegraph stations associated with said channel, a printing tel'egraph recorder at each station including a signal responsive selector mechanism, -a printing inecha- 'nism operable under the control of said selector mechanism and a driving motorfor both of "said mechanisms, means controlled by said channel independently of said selector inec'h'ani's'r'n'at each station for completing the operating circuit "of the motor, meansin each recorder for' s'upp'ress- :in'g operationio'f 'said printing mechanism, means controlled by the selector mechanism at each station for disabling said suppressing "means, ,me'ans controlled by the selector mechanism at each :station for disabling said motor circuit completing means, means --at each station controlledby said selector mechanism for estopping operation of both said disabling means, "and means at each'stationcontrolled by said selector "mechanism for restoring said estoppin'g means to non-estoppi'ng condition.

*4. In 'a communication system, ac'ommunic'a- 65 tion channel, a plurality of" telegraph stations asso'ciatedwith said channel, a printing telegraph recorder at each "station including a signalr'esponsive" selector mechanism, a printing ine'cha- 'nism'operable under the control f 'sa'id selector mechanism and adriving motor for both of said mechanisms, means controlled by said-channel independently of said selector mechanism at each station for completing the operating circuit of ,the motor, means meach reccr er 'for suppress- .ing operation--of-said printing mechanism, means controlled by the selector mechanism at each stat-ion in response to a signal individual to such station for disabling said suppressing means, =rmeans controlled by the selector mechanism at .each station in response to a signal common to -all sta;tions--f or disabling said lmotor circuit completing rneans,-mea-ns at each station controlled .by 'said selector mechanism-in response to asi-ggnal common to ,all stations: for estopping operation pf-iboth-said disabling -.means, and means at each -st-a tion -,controlled by said selector mecha- -,;nis1 n -;in--responseto arSignal common to all sta- .ti ons-.-for;.restoring said estopping means to-nonrestopping conditions, each of said-common signals .difiering-irom the ,others. I

5. In a con munication system, a communication channel, a plurality of telegraph stations associated with said channel, a printing teleag-raphrecorderateach station includinga signal --responsive. selector mechanismaprinting mechainisrn-operable under the control of said selector i'mechanismwand adriving motor :for both ofsai d mechanisms, means controlled .bysaid channel independently oisaid .selector .-'mechanism at each station for completing the operating-circuit .of a

the amotor, means in :each recorder for, suppress.- i s o era o o sai r t nem a sm, me n c t olled :by the .aSBlEQ m a sm at each -station in' response -toaa si nal individual-to such station, andcilso in --response to a signal common to wall stations vfor disabling said suppressing means means controlled eby the selector mechanismtateach station in response to asignal com- -mon-toallstations fordisa-blinggsaid motorcircuit completing means, means at eachstation controlled by said selector ,mechanism in response to a signal common to all stations f or estopping operation of both said disabling means, ,and means at each station controlled by said selector mechanism in response to :a signal common to all stations ior restoring sa id estoppingmeans to. non-,estopping condition, each of said common signals diiieringfrom the-others. v H ,6. In a communication system, Ta communication channel, a plurality of stations associated with-said channel, a, normally operative signal responsive selector mechanism at each station, ;;a record-producing mechanismcontrolled by each of said selectorv mechanism's mean-s forsuppressing operation of said record producing :mechanisms, means controlled :bysaid selector -mechanisms ior; selectively disabling the suppressing .means of their respective record producing mech anisms and means controlled by saiddselector mechahisms ior rendering *unoperated, ones gof v said tdis ablingmeans unresponsive to their, selector-mechanisms. H i .1. H :7. In a communication system, a communication channel, a plurality of stations associated with said channel, a normally operative signal responsiv,e selector mechanism at-each;station, a recordproducing mechanism controlled by each of saidsselector mechanisms, means-gforsuppressing operation 'of said record producing mechanisms, means controlled ,by said selector "mechanisms for selectively disabling the suppressing means, of theirrespective-record 1 producing mechanisms, meanstcontrolledby said selector mechanisms for, rendering unoperated onesof sa-id disablingineans unresponsiveto their selector mechanisms, andmeanscontrolled by said selector mechanisms ior -restoring said "disabling means and said ,last mentioned ,means to nnoperated condition.

trolled by said selector mechanisms for rendering ""10. Ina'com "i9 3. In a communication system, a communication channel, a plurality of stations associated with "said channel, means at each station for transmitting telegraph code signal combinations of equal and predetermined duration, a signal responsive selector mechanism at each station normally responsive to signals generated by any of said transmitting means, record producing mechanisms controlled by said selector mechanisms, means for suppressing operation of said record producing mechanisms, means controlled "by said selector mechanisms for selectively disabling the suppressing means of their respective record producing mechanisms; and means conunoperated ones of said disabling means unresponsive to their selector mechanisms. 9. 'In a communication system, a communication channel, a plurality of stations associated V Wi th said channel, means at each'station for transmittingtelegraph code signal combinations of equaland predetermined duration, a signal responsive 'selectormechanism at each station normally responsive to signals generated by any of "saidtransmitting means, record producing --mechanisms-controlled by said selector mechanisms,normally operated means for suppressing operation of said record producing mechanisms, means controlled by said selector mechanisms in response to individually selective signals or group selective signals generated by any of said transn-iitting means for selectively disabling the suppressingmeans of their respective record producing mechanisms, and means controlled by said selector mechanisms in-response to a common signal generated by any of said transmitting -me'ans for rendering unoperated ones of said disabling means unre anisms. Y

munication system, a communication channel, a plurality'of stations associated with said channel, means at each station for sponsive to their selector mechtransmitting telegraph code signal combinations of equal and predetermined duration, a signal responsive selector mechanism at each station normany responsive to signals generated Many of said transmitting means, record producing m'e'chanisms controlled bysaid selector mecha- *ni'sms, a normally operative driving motor for said selector mechanism and said record produc- "ing -mechanism'f at each station, normally activated means for suppressing operation of said record-producing mechanisms, means controlled by 'saidselector mechanisms in response to signals'generated by any of said transmitting means for selectivelydisabling the suppressing means of their respective record producing mechanisms,

and means controlled by said-selector-mecha- "nisms' for rendering unoperated ones of said disabling means unresponsive to their selector mechanisms." 11. In a communication system, a communication channel, a plurality of stations associated with, said channel, means at each station for transmitting permutation code telegraph signals,

a permutation code signal receiving selector mechanism at each station, a printing mechanism'at each station controlled by said selector mechanism, a normally activated driving motor for said selector mechanism and said printing mechanisms at'each' station whereby said selector'mechanisms are normally operative in response to signals, normally activated means for suppressing operation 5 of said printing mechanisms, means controlled by said selectorme'chafective condition at all stations.

"ni sms inresponse to permutation code signals for selectively deactivating the suppressing means of their respective printing mechanisms, and means controlled by said selector m'echanisms in response to permutation code'signals for rendering unoperated'ones of said deactivating means unresponsive to their selector mechanisms' 12. In a telegraph system, a telegraph line, a plurality of stations associated with said line each havinga printing telegraph recorder and a permutation code signal transmitter, normally activated means associated witheach of said recorders for suppressing operation of the printing mechanism of said recorders, meansat each of said stations selectively responsive to permutation' code signals transmitted by any of said transmitters for deactivating said suppressing means to qualify those stations having their suppressing means deactivated to participate in message transmission and reception, and means at each of said stations responsive to permutation code signals transmitted by any of said transmitters for renderingthe deactivating means at unqualified stations. unresponsive to their respective signals until after restoration of all of .said stations to activated condition of said suppressing means. j

v13. In a communication system a' communication channel, a plurality of' stations associated with said'channeLarecorder at each of said stations including a selector mechanism normally responsive to signals on said channel, aplurality of recording elements selectively controllable by said selector mechanism and anactuator for operating said recording elements, means normally eflfective to block, said actuator upon each attempted operation thereof, means controlled by said selector mechanisms upon response to predetermined signals for disabling said blocking means, and means also controlled by said selec-' elements, means normally efiective to block said actuator upon each attempted operation thereof, means controlled by said selector mechanismup- ,on response to predetermined signals for 'disabling said blocking'means, and means also 'controlled by said selector mechanism upon response thereof to a predetermined signal for estopping operative response of unoperated ones of said disabling means to said selector mechanism unrective condition at all stations.

15. In a communication system, a communicationchannel, a plurality of stations associated with said channel, a printing recorder at each station including a selector mechanism normally responsive tosig nalson said channel, a plurality 'ic'ments, means'normally'efiective to block said of printing elements selectively controllable by said selector mechanism and a bail permissibly iope'rable upo'nea'ch receiving cycle of said selector 'm'echariismifor operating said printing eletil after restoration of said blocking means to ef- "21 bail upon each "attempted operation thereof,

:means rcontrolledcby saidselector. mechanismjupon response to predetermined signals for disabling saidlblocking,means,,and.,means also controlled by said selector mechanism upon response thereof .to a predeterminedxsignal for e'stopping operativetresponse.of.unoperatedlones of said' 'dis- *aabling :means .to said selector :mechanisms until latter-restoration ofsaidblocking.mearis to effective ,condition. atall .stations.

.16. Z In saicommnnicationsystem, a communication channel, a plurality of telegraph stations associated with said channel, a printing telegraph recorder at each station, means in each recorder for suppressing printing operation thereof, a relay at each station operable to disable said suppressing means, a second relay at each station operable to estop operation of unoperated ones of said disabling relays, a plurality of signal responsive selector elements in each of said recorders, a selectable member directly responsive to said selector elements for controlling one of said relays, a plurality of sets of electrical contacts controllable by said selector elements in accordance with the signal responsive operation of said elements, a relay operable under the control of each of said pairs of contacts, and a fan circuit path selectively closable by said plurality of relays for selectively establishing an energizing circuit for the other of the two first-mentioned relays.

17. In a communication system, a communication channel, a plurality of telegraph stations associated with said channel, a printing telegraph recorder at each station, means in each recorder for suppressing printing operation thereof, a relay at each station operable to disable said suppressing means, a second relay at each station operable to estop operation of unoperated ones of said disabling relays, a set of signal responsive selector elements in each of said recorders, a selectable member directly responsive to said selector elements for controlling one of said relays, a plurality of sets of electrical contacts controllable by said selector elements in accordance with the signal responsive operation of said ele ments, a relay operable under the control of each of said pairs of electrical contacts, a fan circuit path selectively closable by the last-mentioned relays for selectively establishing an energizing circuit for the other of the two first-mentioned relays, a secondary selector element controllable by said set of selector elements, a pair of electrical contacts controllable by said secondary selector element, and a relay energizable over a path including the contacts controlled by said secondary selector element and a fan circuit path selectively closable by the relays controlled by the first-mentioned pairs of electrical contacts for releasing the two first-mentioned relays.

18. In a communication system, a communication channel, a plurality of telegraph stations associated with said channel and having a printing telegraph recorder including a selector mechanism and a printing mechanism, a mechanical element for suppressing operation of said printing mechanism, a normally activated electromagnet for presenting said mechanical element in operation suppressing relation to said printing mechanism, first and second normally deenergized relays providing circuit completing connections in parallel for said electromagnet, means selectively operable at each station by said selector mechanism for completing the energizing circuit of said first relay to interrupt one of "22 said connections, me'ans concurrently operstb'le ajt *ail stations "by-said selector mechanisms for-oom- .pleting the energizing circuit "of said second n'elay to interrupt the other of said connections "whereby -'to "release said l'ectroma'gn'et and suppressing means "at anyst'ation having" both relays energized, and means associated with said-second relay for estopping selective energization of unoperated--ones of sai'd iirst relays.

19. "In a communication system, a communication channel, a pluralityofsta'tionsassociated with said channel, a, signalresponsive selector mechanism and a signal transmitting mechanism at each station, a driving motor at each station for said selector and transmitting mechanisms, means at each station controllable from any station for starting all of said motors, a record producing mechanism controlled by each of said selector mechanisms, and means controlled by said selector mechanisms for selectively causing their associated record producing mechanisms and transmitting mechanisms to be operative or non-operative while all of said,motors remain in operation.

20. In a communication system, a communication channel, a plurality of stations associated with said channel, a signal transmitting mechanism at each station, a signal responsive selector mechanism'at each station, a record producing mechanism controlled by each of said selector mechanisms, a driving motor for each of said signal transmitting mechanisms and selector mechanisms and its associated record producing mechanism, means at each station controllable from any station for starting all of said motors, and means controlled by said selector -mechanisms for selectively causing their associated Signal transmitting mechanisms and record producing mechanisms to be operative or nonoperative while said selector mechanisms continue to respond to signals representing record producing operations and said driving motors continue in operation.

21. In a communication system, a communication channel, a plurality of stations associated with said channel, a signal transmitting mechanism at each station, a signal responsive selector mechanism at each station, a record producing mechanism controlled by each of said selector mechanisms, a driving motor for each of said signal transmitting mechanisms and selector mechanisms and its record producing mechanism, means at each station controllable from any of said stations independently of said selector mechanisms for starting said motors, means controlled by said selector mechanisms for selectively causing their associated signal transmitting mechanisms and record producing mechanisms to be operative or non-operative while all of said motors remain in operation, and means controllable only by said selector mechanisms for stopping said motors.

22. In a communication system comprising a plurality of interconnected telegraph stations each having a transmitter and a normally disabled record producing mechanism and a driving motor therefor, the method of intercommunicating among said stations selectively which comprises (1) starting the driving motors at all stations, (2) selectively enabling the record producing mechanisms at the stations to be in ins tercommunication, (3) precluding enablement oi! the record producing mechanisms and disabling the transmitter at all other stations, (4) continuing the operation of all ofsaid motors during a4 interoommunication among said selected sta- I REFERENCES CITED (5) r-edlsablmg the record producing The following references are of record in the .meehanisms at the conclusion of said intercomme of this patent:

, Kinkead, Deceased.

munication, and (6) continuing the operation of said motors as a preparational condition for sub- N T D STATES PATENTS f l sequent intercommunication among any two or Number Name mQre all of the stations- 2,211,232 Hulfish Aug. 13,1940 2,148,435 Carr Feb.,28, 1939 A SMITH KmKEAD 2,129,741 Levy Sept. 13,1938

Administratria." of the l 2,106,805 Lang Feb; 1, 1938 Estate of Fullerton 10 2,152,010 Zenner Mar, 28, 1939

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