US2365750A - Telegraph switching system - Google Patents

Description

Dec. 26, 1944. A. J. DORE TELEGRAPH SWITCHING SYSTEM Filed March 3, 1943 5 Sheets-Sheet 1,

1% I R .r O Y m0 E mi .1 V I 0 NR T .IU T H A T R A N Dec. 26, 1944. J E 2,365,750

TELEGRAPH SWITCHING SYSTEM Filed March 3, 1943 3 Sheets-Sheet 2 INVENTOR ARTHUR J. DORE Dec. 26, 1944. A. J. DORE TELEGRAPH SWITCHING SYSTEM Filed March 5, 1943 3 Sheets-Sheet 3 ATT RNEY Patented Dec. 26, 1944 UNITED STATES PATENT. OFFICE TELEGRAPH- SYSTEM Arthur J. 'Dor, Chicago,, Ill., assignor toiTele-type Corporation, Chicago, 111., a corporation of Delaware ApplicationMarc h 3, 1943,:Serialx-Noeii'ifl99 7 Claims. (01. 178-3) .The present i invention relates to communica:

tions areconnected together over a common loopcircuitand are operated for relaying information successively or in accordance with any other plan to a common central station whereat'there is. prepared for retransmission, perforated tape bearing the messages broadcastby certainones only of said stations to the exclusionof the information'transmitted from other ones thereof.

In-accordance with'a specific contemplation. the election to record upon a tape from among said several broadcast stations or in other words, the determination as to which one or ones of the stations-is to affect the operation of prede-' termined perforators is preferably made at the central station by predeterminately associating reperforator shunt relaysto the control of corresponding ones of a series of'reperforator semittedilby' the system shown in ,said copending application, onlyrbylsending anew: circuit establishing' signalsat each linerbeginning: and-thereby reestablishingmthe;circuitrassociation at the commencementnfieaclrline. :Insomeinstances such a :systemtmightibe;ope1:ated;:at some economical disadvantage and in order to overcome this difi'lculty it) is herewith proposed ctotprovide a system having n rally. similar objective but providing' for \the continuous circuit establishment between broadcast .transmitting and: reparioratins station apparatus during the communication 10f message material which exceeds one line in length without lrequiring :reestablish-ment of circuitlconnections:atithestartof each. line of printingt Accordingly, the primary object: of the present invention is the; provision ina system, of station selection-by meansiof'vwhich retransmission apparatus: may zbe various'ly conditioned for operation according stem-station identification signals that -are'transmitted along with line-length or lecting relays. This arrangement of establishing connections between certain broadcast stations and-certain transmitting reperforators maybe in accordance with a permanent arrangement or as where preferable, the association maybe variedor adjusted throughout the courseofa givenperiod of transmission so that; for example,

at certainhours of a day broadcast transmitting I stations which disseminate certain information may be associated with reperforators which-require such information then only and not -at other'hours of the day.

The present application is related to anapplication filed concurrently under the name of- W.- J. Zenner, Serial No. 4773800, filed March 3, 1943,-wvhichincludes a telegraph switching system also designed for automatically establishing v whichexceed one 'linein length'canbe transbulletin messagesiand:iwheregsuch apparatus, once conditioned may, ,under the control ,of preventative signals. be continuedlinacondition.for a duration exceeding; zaasinglejine. length of communication.

. -Briefly stated; the present invention contemplatesa system:ofgcommunication. control wherei by a series :of "outlyinge stations} is connected over a z-single incoming line with a common impulse repeating relay-located at a ,centraloflice. The common relay repeats the signals gtransmitted by any one of the outlying stations to aseries l of local rel-ays=serially connected in a loop circuit,

one of which may betassociated directly with a receiving :pageprinter zthus'makin a page recording of all of..thevmessage material received over: thealine. "Another. one of therelays may be associated with. a mechanical code selecting, apparatus-in whichsa plurality of special function selector bars are providedfor. closing supervisory contacts whi'ch-will be: described later and which affect theperformance of a set. of conditioning relays. Inxadditionrto'these, a series of reperfor'ator control relayspare provided in the loop circuit, each one 1 of .whichaffects rthe initiation and control overa tape-vreperforatorsuch as of the type disclo-sed:in-U.:S. Patent No. 1,884,743. Of theselattenrelays all-are provided with elec trically shuntablearmatures so that. any one or more-of themmay be rendered ineflectivein the performance 'of initiating its associated reperforator apparatus throughthe simple expedient of-maintaining 'closedits control circuitnotwithstanding the fluctuations of its armature in response to the signals induced upon it by the central station loop circuit. The manner in which these shunt circuits are supervised will be described in greater detail hereinafter. The aforementioned meehanical selector apparatus has for its primary purpose the supervision over a system of conditioning relays which in turn affect the performance of a series of shunt selector relays in the supervision of said shunt circuits.

For a" more comprehensive understanding of the present invention, reference will now be had to the accompanying drawings and to the following detailed specification in which corresponding reference characters designate similar parts throughout and in which,

Fig. 1 is a schematic circuit diagram of a central station illustrating in block outline the various pieces of apparatus utilized in the performance of the afore-designated objects;

Fig. 2 is a portion of a schematic circuit diagram featuring a set of conditioning relays and a conventional designation of a mechanical selector associated therewith which perform a primary supervision over a series of shunt selector.

relays illu trated in-another portion of the schematic circuit diagram;

Fig. 3 is a further portion of the schematic circuit diagram described in connection with Fig. 2 featuring the electrical circuit arrangements of the shunt selecting relays; and

Fig. 4 is a further portion of the schematic circuit described in connection with Figs. 2 and 3 featuring a set of reperforator shunt relays whose armatures control the establishment of corresponding shunt circuits for affecting the performance of the reperforators.

In Fig. 1 of the accompanying drawings, the reference character designates a dotted outline representing a central station. A signaling line |2 extending into this ofiice is connected with a polar relay |3 whose armature l4 responds to the impulses induced over line |2 by any one of a series of outlying stations I5, IE, or H. When no signals are impressed upon the incoming line l2, armature I4 is adapted to engage its left contact is, maintaining closed a loop circuit l9, which includes in series the receiving relays 2| and 22 of monitoring page printer 4| and a mechanical selector unit 42, both of which will be described later, as well as four control relays designated 23, 24, 25, and 2B, which supervise the performance of fourreperforators 21, 28, 29, and 3|.

Each of the prepared tapes or control forms which leaves its reperforator 21 to 3| is thereafter fed through a sensing apparatus of aretransmitter 32, 33, 34, or 35. Accordingly, the signals which are impressed upon the respective prepared control forms are by the associated tape transmitters converted into electrical signal impulses sent out over lines 36, 31, 38, or 39.

The subscribers receiving stations which may be located variously upon the lines 36 to 39, may be interested in obtaining information disseminated by different ones of the afore-mentioned series of broadcast or transmitting stations H3,

H5, etc. Moreover, the subscribers on a line may desire to exclude information sent by others of the broadcast stations. Accordingly, means have been provided whereby under the, control of adjustable switching apparatus, any one or more of the reperforators 21 to 3| may be made responsive to the information broadcast by any of the transmitting stations l5, I5, ll, etc. to the exclusion of such information broadcast by other ones of said stations. The manner in which this selectivity is accomplished will now be described in specific detail having particular reference to the disclosures of Figs. 2 to 4, inclusive, the apparatus thereof being but generally designated by symbols in the schematic showing of Fig. 1.

Th magnet 2| controls the operation of a monitor printer 4|, and since this magnet is located in the primary loop circuit and is accordinglyresponsive to all of the signal impulses coming in over line l2, the matter printed by the monitor printer M will include the total of all broadcast messages over line l2 coming from any one of the broadcast stations l5, l6, l1, etc. The reference numeral 42 designates a mechanical selector apparatus which may be of the type illustrated in copending U. S. application Serial No. 405,301 filed August 4, 1941, now Patent No.

2,323,438, granted July 6, 1943. This mechanism page printer apparatus affect any printing opera tion but only certain collateral functions uch as space, blank, letters shift, line feed, and carriage return. These signals have been chosen rather than printing signals in order that no printing operation will be made by the monitor printer or any other printers Which may be connected into the line, during the time that the station selection functions are performed.

It is proposed that each of the broadcast stations l5, l6, l1, etc. be apportioned a period of time in a succession of periods one for each station broadcasting over line l2, during which it will transmit one or more messages concerning items of information which are to be issued to any or all of the outgoing lines 36, 31, 38, or 39. Each such broadcast station I5, I6, I1, etc. will begin its interval of transmission by sending out a letters shift signal, which will serve to close the contact pair 55 and then issuing a carriage return signal. In the operation of a page type printer such as represented by the reference character 4| Fig. 1, this type of signal serves 'to return the printing carriage to the beginning of a line in preparation for the printing of a message at the start of such line. Thereafter the broadcast station follows with an identification signal or combination of such signals made up preferably of the three special function signals, letters shift, space, and blank. Following this the station will transmit another carriage return signal designating that its identification signal has been completed and that; the message proper is to be sent. In order to make certain that sufficient time has been permitted to elapse following the second carriage return signal and preceding the first message character to clear said carriage return signal through the selector mechanism 42 and the conditioning and shunt selector relay groups as will later be explained, a precautionary time delay signal in the form of another letters shift code is transmitted. This case signal will have no effect whatever at this time on either the page printer or the line selecting apparatus. Thereafter the station will proceed to transmit its message which may consist of any number of words constituting a page elusive.

2-;se5yzsowidth line -or,in accordance with the instant adaptation, even exceeding such a linein length. -When: amessageis completed before the printerreaches the end'of a line or at the end of a line the carriageshould be advanced to a sucing;a new connection and for receiving a new message. Means have been provided, however, whereby upon the issuance of.a line feed signal which is followed by a special signal before the carriage return signal, there is prevented the disconnection then in existence and instead the printing of asucceeding line may continue'as a part of the same line connection and without requiring that a new selecting signal be transmitted.

The selection for retransmission among the several reperforators 21 to 3| is obtained by a set of nine shunt selectingxrelays generally designated at 43,Fig. 1, and diagrammatically illustr ated in Fig. 3 of the complete circuit diagram. In accordance with the operation of these nine relays any one of which may be energized to the exclusion of the remainder, certain ofthe four reperforators 21, 28, 29, and 3| are placed in condition to respond to the signal impulses repeated by their respective magnets 23 to 26, in- The manner in which these shunt selecting relays are energized Will now be described in conjunction withan explanation of the'three conditioning relays which constitute a setygem erally designated 44, Fig. 1, the wiring diagram ofwhich is disclosed in the right-hand portion of Fig. 2 and the individual relays of which are designated 45, 46, and 41. The mechanical selector 42 is portrayed conventionally in Fig. 2 by its five selectable elements which have been indicated as follows:

l The carriage return code bar by the index CR, the letters shift code bar by the index LS, the space code bar by the letters SP, the blank code bar by theletters BL, and the line feed code bar by the letters LF, Upon the energization of any of the code bars CR, LS, SP, or BL, thereis effected the closure of an associated contact pair 48, 49, 5|, or 52. Another, contact pair designated 53, however, which is operated by the selectable bar remains normally closed and is opened briefly during the selective operation of the line feed bar LF.

A mechanical selector apparatus 42 of the type contemplated may consist of a modified telegraph printer provided with a contact pair 54 that is operated by the universal bar and thereby closed invariably with the receipt of each signal, and a contact pair 55 which is closed during the time that the case shift mechanism is disposed inits letters shift position, and open during the time that it is disposed in its numerals shift position. v

The reference character 56 designates a circuit connecting in series thecontact pairs 54 and 55 vviththe carriage return and line feed contact pairs 48 and 53. In order to be effective towards the purpose-of station selection themechanical selector apparatus will of necessity be required to be, placed in the letters shift position, as already explained. When this apparatus is disposed'in its figures shift position, the contactpair 55'Will remain open, and the completion'of supervisory control will thereby be prevented,

tTherewill now be described:illustrativevexam ples :of' operation to show tho-w :the conditioning relays :45, 416, and 41 in response to the various manners of operation of .themechanical selec torbars CR, J- LS,. SP, BL, :and servet0 .ener-- gizeonecof the shunt selecting relaysconstitute ing the grouptdesignated SP, SP-LS, SP,BL,,

for cutting :out those reperforators Y28 sand 31 which are notzthen' to receive signals, by accordingly conditioning the shunt relays 51,258,159; and :6l. erally indicated 62,iFig. :1, and they in turn may upon energization attract their associated: armatures63, 64, 65, and-66, respectively,-interrupting obvious shunt circuits that normally parallel acorresponding series of ,contactarmatures-:61, 68, 69, and 1|, which fluctuate in response to the energization and de-energization of therloop circuit supervisory magnets 23 to '26, afore-described, as-controlling the reperforator units.21 to3l, inclusive.

Under the example chosen'thelines 36 andq38 are .to receive signals transmitted by station 15. Accordingly, itwill be required that shunt armatur'es Hand 66 become attracted by the energization of their associated shunt relays 58 and 6l,.so that thereafter when-the armatures 61 and 69 rfiuctuate in response to the energization of magnets Hand 25, theopening and closing. of the'control circuits of reperforators 27 and. 2 9 will be effective toward the purpose of operating the tape perforating and'code conditioning apparatus of such .units, 'while the other units 28 and 3 I, remain dormant.

Referring now more particularly to Figs. 3cand 4,it.wi11 be noted that in order to energize magnets 58.and 6| itwill benecessary toplace current upon the bus bars 14 and 15 while excluding it from "thebus bars 12" and 13. For this purpose anyone of the shunt selectorxrelays SP, BL, LS-SP, etc. may be especially conditioned, for itis but necessary that such relay have its objective armatures 16: to 19 electrically strapped to cable 82 ina suitable manner. Thus, torender relay.SP-BL elTective-in the performance of. I

the instant selection, its objective armatures 11 and19 must be connected to cable82 whileits armatures 16 and 1-8 are disconnectedrtherefrom. In accordance with a contemplated design, each one of the shunt selecting relays-SP, SP-LS, etc., is provided with four contactors '16, 11, -18, and 19, communicating respectively. with thenbus bar contacts ofconductors 12, 15, 13, and 14. To assignany one of the shunt selecting relaystothe preparation of any combination of the lines-36 to 39, it. is'but necessaryrto connect the enablingcontact switches 8| thereof which prepare aground supply. circuit from the common bus wire 82 upon the armatures'16 to 19 so that thereafter, uponenergization, this ground will be supplied to thecorresponding shunt relay energizingbus'n to 15. v i

.For convenience in manipulating theground conditioning contactors 8|, itis proposed that a multiple button panel type of control switch 830, Fig. 1, be provided having thereon suitably indexed push button devices for effecting the closure of those contactors 8| of any -re1ay"SP, SP-LS, sP-DL,. etc. :which is to become associ- 15. Any reperforator: shunt-relay of the-Fig. 3 .group may be employed These rel ys form p rt of :a unit genated with predetermined ones of the outgoing lines 36 to 39. In this way subscribers stations by having previous arrangements with the control operator at the central station may obtain limited service from certain ones of the broadcast stations I5, I6, I1, etc., by having line connection with such stations at predetermined intervals of a day to the exclusion of such connection at other times.

Under the example chosen, a particular broadcasting station I5, having the identification symbols of space-blank signals, will be operated to retransmit signals over the outgoing lines 36 and 38. This will require that a relay such as the one designated SP-BL, be selected and have its objective armatures 11 and 19 connected so as i to prepare for ground. which is later supplied over the bus wire 82 to the lines 14 and 15. It is equally important that its armatures'16 and 13 be disconnected from ground. Upon the energization of relay SP- BL, by the space-blank selecting signal combination, its armatures will be locked to operated position and will connect with bus wire 82 which later obtains ground to enable the energization of the shunt relays 58 and 6|. There will now be explained the manner in which these selecting signals are effective in energizing relay SP-BL,

Any station identification signal transmission will be preceded by a carriage return signal, the receipt of which by the mechanical selector 42, Fig. 2, will cause its associated carriage return code bar CR. to be moved into its selected position closing the contact pair 48. It will be recalled that the selector is placed into its letters shift position so that the contact pair 55 is closed and as an incident to all operations the universal contact pair 54 is momentarily closed thereby completing a circuit which is traceable from positive current source at 83, over lines 84 and 85, through the winding of the third conditioning relay 41, then out over conductor 86, contact pair 88-81 (normally in engagement), line 89, through the contact pair 46 (now closed), contact pairs 54 and 55 of conductor 56, through the contact pair 53, to the negative bus wire 9I.

As a result of the completion of the aforedescribed circuit, conditioning relay 41 becomes energized drawing up its contact tongues 92, 93, 94, and 95. As a result of the operation of contact tongue 93, a holding circuit is prepared for relay 41 traceable from positive terminal 83 over lines 84 and 85, through the Winding of relay 41, line 96, contact pair 93 which is now closed, line 91, contactor 98 of relay 45 which is engaged during the de-energized condition of said relay, line 99, to the contact point IIII which is now engaged with the make-before-break contactor I02 during the de-energized condition of relay 46, through the winding of said relay 46, out over line I03, contact pair I04 which remains closed until relay 46 is operated, line I05, contactor I06 which remains closed during the de-energized condition of relay 45, lines I01, I1 5, and I08 to the junction point I09. Thereafter, this circuit is traceable over line III to the contact pair including contactor 95 which is at this time closed due to the energization of relay 41, to grounded negative bus terminal 9L As a result of this circuit relay 46 becomes energized drawing up its armatures II2, I04, I I3, H4, H5, 81, and H6.

As a consequence of the attraction of its arma ture I I2 against the make-beiore-break contactor- I02, a locking circuit is established for relay 46 traceable from positive bus wire 83, line 84, conductor I I1, armature I I2 which is now in engagement with contactor I02, winding of relay 46,

2 then out over line I03, contact pair II4 which is now closed to the energization of relay 46, then over line II8, contact pair 95 to negative bus terminal 9 I It is to be noted that ground is also available to the afore-described conductor II8 over line III, contact pair 53 to grounded bus 9| and this latter course is effective when contact pairs I0 I- I02 become separated due to the energization of relay 46 thereat opening the holding circuit for relay 41 and causing the opening of contact pair which is the alternative ground connection for conductor H8.

The third conditioning relay 41 is thus released and all of its armatures are restored and now only relay 46 remains energized with its several armatures drawn up into their forward position. As a result of the closure of contact armature I I6 with its contact point, minus current from the negative bus bar 9| is made available to the contact pairs 495I and 52 of the letters shift, space, and blank selector bars of the mechanical selector 42. This circuit is traceable from minus bus bar SI through the normally closed contact pair 53 then through the contact pairs 55 and 54 of branch conductor 56, line II9, contact pair H6, and line I2I to the junction point I22. Thereafter the grounded negative is traceable over line I23, contact pair I25 of relay 45 which is now closed due to the de-energization of relay 45, line I26 to the three upper contacts of the aforedescribed contact pairs 49, 5|, and 52.

Thereafter upon the energization of any of these three contact pairs, ground maybe extended over lines I21, I28, or I29, respectively, of the contact tongue I3I, I32, or I33 of the shunt selector relay BL, LS, or EP. In accordance with the instant example the first character of the identification signal being space, there will be operated accordingly the SP relay, Fig. 3, over the following circuit. As a result of the energization of the SP selector bar, Fig. 2, the contact pair 5| will be closed and negative potential from line I26 will be extended over the branch conductor I28 traversing the contact pair I32 of there will be drawn up its several armatures I39,

I4I, I33, 16, 11, 18, and 19. As a result of the drawing up of armature I39, relay SP is no longer dependent upon minus current incoming through line I36 but may instead obtain minus current over a circuit which continues over line I42 through the now closed contact pair I43 of a make-before-break contact set under the control of relay SP-LS, then over line I44 through the now closed contact pair I45 of the make-beforebreak contact set of relay BLSP, thence over line I46 to the now closed contact pair I41 of the make-before-break contact set under the supervision of relay LS-BL, thence over line I48 to the now closed contact pair I49 of a make-beforeb-reak contact set under the supervision of relay LSSP.

Thereafter the circuit is traceable over line I5I before-break contact set under the supervision of relay BL-LS, thence over line .I 53to the normally closed contact pair I54 of a make-before- .break' contact set under the supervisionof relay SP-BL.- Thereafter, the circuit is traceable over line I55 to the junction point I56,Fig. 2, branch conductor I51 to. the contact armature H3 which BL of the mechanical selector 42, Fig. 2. In consequence. the contact pair 52 is closed extending 2,365,750 .to thernormallyclosed'contact pair I 5.2 of a makeground from the afore-described supply line I26 on to the further conductor I29, which connects with the contact armature I33 of relay SP-now attracted and in engagement withits front con- This extends ground over the.

tact point I62. branch conductor I63 through the winding of relay SPBL over line I64 to the positive bus wire I38 causing, said relay SP-BL to become energized. I

As a consequence of the energization of relay SP-BLit draws up its armatures I65, 16, 11,18, and 19. Asa result of the operation of armature I65the make-before-break contact assembly of relay SPBL is operated so as to separate the contact pair I54 which had been in the locking circuit of relay SP and holding the afore-described shuntselector relay energized. Thus the energization of the relay SP-BL releases the previously energized relay SP and since the connector straps 8| of relay SP-BL, are so arranged;

.perforators 21 and 29 but not reperforators 28 and SI. In this way signals will be issued over lines 36, and 38, but not lines 31 and 39.

Followingv the transmission of the secondidentification signal blank as afore-described thereby completing the transmission of the station identification signals constituted of space and blanks and recordable bythe energization of relay SP-BL, ityj-S contemplated that in accordance with. the practice the stationwill transmit another carriage return signal causing to be operated the CR selector, of the mechanicalseleotor unit :42, Fig. 2. There isefiected thereby a closure of the contact pair 48 which operates to .shortlcircuit the winding of the thirdconditioning relay 41 momentarily beginning withminus battery conductor 9I'and traceable over the contact pair 53 through the closedcontactors 55 and 54" of branch circuit 56, then over 'line II9 through the contactor N6 of the second conditioning relay 46 which is atthis time energized,

over line I2I tolthe junction, point I22, then over "branch conductor I66, contactor 92, to the left terminalwinding of relay 41, the right terminal being normallyv minus. Assoon as the universal contactor 54. is opened, however, which function occurs after but a brief interval of closure due to the characteristic operation of. the universal bar inrt'he mechanical selector apparatus, the aforedescribed shorting circuit is broken and immediately operating current is made available to relay 41 over the following course.

Beginning with positive at battery terminal 83 this circuit is traceable over conductors 84 and 85 through the winding of. relay 4! then out over conductor 86, through the contact tongue I I5 and its contactor with which it is at the time engaged due to the energization of the second conditioning relay- 46, then out over line I61 to the contact tongue I69 of relay 45 which is now closed, thence over conductors I 69 and I98 to the junction point I69. Thereafter the course is traceable over branch conductor I II through the contactor 53 which is closed to minus battery bus 91.

This causesrelay 41 to attract. again its armatures92, 93, 94, and providing an alternative source. of negative current through armature 95 so that theenergization of relay 41 is no longer dependent upon the continued closure of contact pair 53. The alternative negative potential supply source is traceable at junction point I99 over line .I II through the contact pair 95 to the minus bus wire 9 I.

This same, alternative connection to minus current also supplies a holding circuit for relay 46 whcsefminus terminal extends over line I93, through the contact pair II4, line II8, through the, contact pair 950i relay 41, and then to negative bus .9I. The samecontact tongue 95 of relay 41 also provides an alternativenegative source connection over the following course, from the minus terminal of relay 45 through common contact point I13 of the 'make before-break contact switch of relay 45, its armature I14, lines I15 and I98, to the junction point I09,.then over line I II to the contact'pair 95 of relay 41, to ground minus bus wire 9 I;

signal, therefore, relays 45,46, and 41 are all energized and so held over self-locking circuits in readiness for the transmission of a messa e to those of the retransmitting perforator stations 21,

28, 29, and 3I that have been selectively conditioned due to the corresponding operation of the reperforator shunt relays 51 to BL This was obtainedby the energization of one of the selecting shuntrelays of Fig. 3, in the particular instance, the relay designated SPBL.

As has-already been explained, each relay of this group is not necessarily committed to any particular arrangement of conditioning the reperforators-21 to 3I because any one of these relays SP, BL, etc., may, if desired, be variously connected'by the operation of the straps or connector switcheszBI so as to render it responsive to select any one or ones of the reperforators under the control of the particular identification signals spaceiblank, letters shift, etc. as'may be dev.serveto restore the carriage to=the start of line position. and. to. rotate. the platen throughout an angular distance to present a subsequent line for condition to await a subsequent message and station identification signals.

If, however, the message which is transmitted by any one of the stations I5, I6, or I1 exceeds in line length the width of a page, then means are provided whereby through the transmission of the carriage return signal followed by the letters shift signal, before the line feed signal, there is eiTected a suspension of the wipe out or clear out operation causing instead the performance of the mechanical carriage return and line feed functions for the purpose of conventional printer control, while yet maintaining circuit connections with the destination station 21 to 3| as established by the previous line of transmission. Moreover, this arrangement may be perpetuated so long as any one of the lines is terminated by the transmission of the three instead of the two concluding signals as afore-described.

The transmission of the concluding carriagereturn signal has the effect of short circuiting the second conditioning relay 46. It will be recalled that positive battery source is available to relay 46 from positive battery terminal 83, over line 84, resistance I16, line II1 to contact armature II2, then through contact I02 to one of the terminals of the winding of relay 46. Upon the closure of contact pair 48, however, grounded battery is extended to this side of the relay thereby neutralizing the effect of its holding currentthrough a circuit traceable as follows. Beginning with minus bus 9 I, through the contact pair 53, contacts 55 and 54 of branch conductor 56, through the contact pair 48, line 89, line I11 to the contact pair I18 of conditioning relay 45, now closed, then over line I19 to the contact pair 94 of relay 41, to the branch positive current conductor II 1 at junction point ISI.

This places minus battery at both ends of the relay 46 causing said relay to become de-energized and thereby release its locking circuit. It will be recalled that the locking circuit for relay 41 was traced through make-before-break contact set H of relay 46, and that as a consequence of the de-energization of relay 46, connection is broken between its armature I20 and the intermediate contact I82. Before the disconnection, however, contact I82 makes engagements with its alternative contact point I83. This circuit, including contact point I83, leads to the contact pair 48 of the carriage return pull bar and accordingly, the holding of relay 41 in its operated position will then prevail so long as the contact pair 48 remains closed over a path traceable from, minus bus 9|, through the contact pair 53, contact pairs 55 and 54 of branch conductor 56, through the contact pair 48, line 89, to the junction point I84, then through the contact pair I85, now closed, due to the energization of relay 45, .over line I86, through the contact pairs I83-I82 over line 86, to the winding junction I09, line I08 to the junction point I81, then over line I15, contactors I14 and I13, through the winding of relay 45 then out over line I88, line 84 to positive battery terminal 83. Thus relay 45 depends upon the continued closure of contact pair 53 for retaining itself in locked condition.

Negative potential is meanwhile supplied to the line I55 of the shunt selector relay group, Fig. 3, over a course traceable from minus conductor 9I over line I6I to the junction I59, then over line I89, through the contact pair I9I of relay 45, line I92 to the line I55, through the contactor. I 65, winding of relay SP-BL, then out over line 64 to the positive bus wire I38. This maintains relay SPBL energized during the time that relay 45 remains locked.

Negative potential is also provided to the minus branch bus 82 during the energization of relay 45 over a course traceable from minus conductor 9| through the line feed contact pair 53, over conductor IN, to the junction I09, then over lines I08 and I15, through the contact pair I14- I13 to the common negative bus branch 82. This of relay 41, then out over lines 85 and 84 to the I to lines 82 and I56.

source of negative potential is also dependent upon for the continued energization of relay 45.

At this time if a line feed signal were to be sent actuating the line feed pull bar LP, the contact pair 53 would be opened removing minus current potential from a circuit which had been holding relay 45 locked and thereby permitting said relay to become de-energized releasing also the afore-described available ground connections However, if the message under transmission is one which requires more than a single page printer line for its recording, a line feed signal must not immediately follow the transmission of the last described carriage return signal but instead a letters shift combination signal should intervene, causing to be closed the contact pair 49 for establishing a circuit to re-energize the second conditioning relay 46 as follows.

The new energizing circuit for relay 46 is trace able from positive battery terminal 83, over line 84, resistance I16, lines I I1 and I93, through the contact pair I94, now closed due to the energization of relay 45, line I96, through the winding of relay 46, then out over line I03, through the contact pair I04 now closed due to the de-energization of relay 46, line I05, contactor I91 now closed due to the energization of relay 45, line I98 to the junction point I99, then over line II9, circuit 56 including its contact pairs 54 and 55, through the contact pair 53, to minus bus terminal 9|.

Accordingly, relay 46 becomes energized pulling up its several armatures as afore-described and establishing a locking circuit for itself traceable from positive battery terminal 83, over line 84, through resistance I16, line II1, to the junction point I 8|, then through contactors H2 and I02 through the winding of relay 46, over line I03, through the contact pair II4, now closed, lines H8 and III to the junction point I09. This circuit is further traceable over line I1I through the contact pair 53 to the minus bus wire 9|. The operation of the mechanical selectors contact pair LS has no effect upon the shunt selector relays, Fig. 3, because at this time, due to the energized condition of the first conditioning relay 45, contact pair I25 is open and thereat prevents the extension of positive current source to the common line wire I26. v

With the operation of the conditioning relay 48, whose contact pair 4' is adjusted so as to aiclo'se ran instantirb'eiore the "contact pair i- I04 is permitted to open, a lo'cking current is estab- 'lished over line- 'I93 which had extended-through the contact -.pair l M and is now extended through -theicontact pair II4, line II B,"line "I I I vto -the i junctio-npoint|fl9,'.then over line =I1I tothe junction point'53 and-minus bus 9l. As was the case during the previously described operation, momentary closure of contact pair 54 as the re- "sult of'the operationoi the universal bar in the mechanical selector apparatus; prevented the im- -mediate-energization of relays-41 "as a result of the energization of relay-4B which otherwise would proceed overthecourse beginning with theminus bus 9l through-the contact-pair 53, line.

I'1l -to the junction I09, then over lines H18 and -I69 to the contact pair-158, line 161 through the contact pair 1 I I -I82 then over line'96 through the winding i of relay 41, line 85- to positive bat- "tery terminal 83.

Thus, the closure of contact pair 92, duetothe H de-energizing conditionof relay 41= and theoporation of the universal contactpair 54-of the mechanical selector, momentarily prevents the 'energization of relay 41 by applying minus batterypo-tential at the line 85' terminal of" the relay -41'winding tractable -'from minus bus --'-9I, through the -line feed contact pair 53, then through contact pairs 55 and 54 of conductor "-56, over conductor =II9 through "the contacts:

tongue I I6-and its contactpoint of relay 46'Whl'Ch is then energized over" lines 1 I2I,'junction I22, then over line-l to 'the'contact-pair 92 ofrelay 41, applying "negative "potential at junction 209 of line which connects with'the-positivebatnection for the negative-potential of'thelocking W circuits of the-relays 45, 46, and 41, after the manner already described so that upon the operation of the line feed contacts 53 in respons to the conventional line feed end-of-line signal, the opening of contact pair 53 will not interrupt the established connection between the incoming transmitters I5, I6, I1, etc., and the particular ones of the reperforators 21, 28, etc., but will merely function idly so far as the station selectionapparatus is concerned, permitting the succeeding line to be printed under the same conditions of line connection as prevailed for the preceding line.

There will now be described another example of station selection in accordance with which an identification signal of but a single signal component will be employed such as the spacing signal. The spacing relay SP, Fig. 3, will be noted to have three of its straps 8|, connected with the line 82. A difierent selectivecondition will now obtain because its contactors 11, 18, and 19 alone are thereby conditioned whereas its contactor 16 is disconnected at strap switch 8|. Accordingly, upon the energization of relay SP, selective communication will prevail for reperforator shunt relays 5B, 59, and 6| but not for relay 51.

As with the case, of rthe preceding selection. :the outlying station I5,:I6, or I1 will transmit a carriage return signal efiecting the closure 'oi -55, and54'oVer line'89. ItWill be recalledthat =at thestart of each selection none of the relays :45,.46,'o'r -41 is energized andtthatbecause the extension of negative potential over line'82'requirestheenergizationcf relay 45, anyof the previously operated ones of the shunt selecting -relays,'Fig. 3, has been released. Fromline v89 :the-afore-described circuit is traceable over conx-tact pair 81-438, now closed due to the-de-energization of relay 4.6, then over line 86 to the winding of relay '41, then over line 85, through a rearmatures 92, 93, 94, and establishing for itself a locking circuit over armature 93 as already described above. The winding of.relay.46 lies in the locking circuit for relay 41 so that accordingly, 'due to theattracticn of armature-93, an

energizing circuit for relay :46 is thereby established as a result of which its several armatures II2, I94, II3, etc., are drawn up. Relay-46 establishes for itself a locking circuit through the operation of armature H2 in supplyinga new source of positive current over line I I1, meanwhile supplementing the existing source over line 99 through the operation of its make before- -break contact set in I-I02.

The separation of the'contact pair Int-I02 opens the locking'circuitfor relay 41 whereupon signals for operating the identification signal contact pairs 49,'-5l, or52. Under the supposed example, there will now be transmitted a single selecting signal by one of the outlying stations Willcause the closure of contact pair 5|. As a result, minus potential, which had been available as far as the branch conductor I26, is now I5; I6, I1, etc., such as th spacing signal which extended over conductor I28throughthe contact pair I32 of relay LS thenover line I34 to thecontact pair I35 of relay BL, line I36 through the winding of space relay SP to the common positive bus line I31, causing to be energized the relay SP, and drawing up its several armatures I39, I4I, I33, 16, 11, 18, and 19. Accordingly, there will be brought into operation the reperforator shunt relays 58, 59, and GI to the exclusion of the relay 51.

In a similar manner, through the operation of any one of the relays SP, BL, LS,'SPLS, etc., there may be obtained a responsive selection to any signal combination of the three components LS, SP,. and BL due to the operation of their cor. responding selector bars in the mechanical selector, which in turn are controlled by the function signals transmitted by stations I5, I5, I1, etc.

While the present invention has been explained and described with reference to a particularly contemplated circuit arrangement, it is to be understood, nevertheless, that numerous modifications and variations may be made without departing from the essential spirit or scope thereof. Accordingly, it is not intended that any of the foregoing detailed description nor that the specific illustrations in the accompanying drawings shall constitute the limitations upon its spirit or scope except as defined by the hereunto appended claims.

What is claimed is:

1. In a broadcast system, a central station, an incoming line for said station including a plurality of bulletin transmitters, a plurality of re-.

paratus for sending an end-of-line signal for restoring page printers to beginning of line position, line switching control apparatus also responsive to said end-of-line signal, and e1ectromagnetic means conditioned by a special control signal preceding said end-of-line signal for nullifying its line switching control.

3. In an automatic exchange system, an incoming line, a plurality of outgoing lines, a plurality of transmitting stations seriall connected over said incoming line having means for sending bulletin messages comprising initial identification signals and concluding signals; a plurality of retransmission apparatuses including perforating devices for issuing signals over related ones of said plurality of outgoing lines, means responsive to said bulletin message initial identification signals for establishing communication between said incoming line and predetermined ones of said reperforating devices, means responsiveto said concluding signals for releasing from communication with said incoming lines those of said reperforating devices with which communication was established by the initial signals of a related message, and relay means under the control of a special signal preceding said concluding signal for rendering said communication releasing means nonresponsive to said concluding signal.

4. In a system for automatically connecting one or more of a plurality of outgoing lines with a common incoming line, a selector mechanism comprising a plurality of individually selectable elements responsive to telegraph printer function signals exclusive of character printing signals, a system of relays responive to any one or more function signals for establishing communication between said incoming line and certain one or more of said outgoing lines in accordance with the particular nature of'the signals, means responsive to an end-of-line signal for disconnecting said outgoing lines from communication with said incoming line, and apparatus under .the control of a preconditioning signal immediately .preceding said end-of-line signal for disabling said disconnecting means.

5. In a telegraph signaling system, an automatic station selecting apparatus comprising means responsive to combinations of certain permutation code signals for establishing communication between an incoming line and certain ones of a series of branch circuits according to the particular signal combination, apparatus responsive to certain periodic function signals for disconnecting said incoming line from said branch circuits, and means responsive to a disabling signal for preventing said apparatus from responding to its said disconnect signal.

6. The combination set forth in claim 5 in which said disconnection is achieved in response to a line feed signal terminating the transmis- I sion of each page printer line width of communication, and in which said disabling signal is a case shift controlling signal.

'7. In a telegraph communication system, a station selecting apparatus responsive auto matically to signals preceding a 'message line, comprising electromagnetic means selectable by certain printing function signals for establishing a line switching connection between an incoming line and corresponding ones of a class of branch circuits, apparatus responsive to endof-line printing function control signals for breaking said connection between said incoming line and said ones of said circuits, and means responsive to a disconnect preventing signal for immunizing said apparatus from responding to its said disconnect signal.

ARTHUR J. DORE.

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