US1553417A - Printing-telegraph system - Google Patents

Description

Sept. l5, 41925.

' G. s, VERNAM l PRINTING TELEGRAPH SYSTEM Filed Aprir v, 1920 2 sheets-sheet 2 maar www www INVENTOR.

BY L yToRNEY 4 lio duce a printing telegraph system in whichV jPat'ent'edSept". 1 5, 1925*. I. A

GILBERT s.

ANDTELEGRAPH COMPANY, A ooaPoRAfrIoN or NEW YORK.

PRINTING-rumana SYSTEM.

Application fried April 7, 1920. serial No. 371,963.

To all who/mit may concern:

Be it knowntliat l, Gtnnit'r S. VERNAM, residing at Brooklyn, in the county of Kings and Stateof New York, have inventedA certain Improvements inv Printing-Telegraph Systems, of which the following is a specificatiori f This invention relates to .signaling'sys-A tems, and more'particular'ly to systems for transmitting printing telegraph signals.

One Vof the objects of this invention is to Aprovide means whereby printingtelegraph signals'niay be transmitted from a central A- oilice on the main subscribers' stat-ion without the useof roarydistributors at the local station.

Another objectof'tlie invention is to protlie printing telegraph c ode signals may be transmitted over alternating carrier currents, as Adistinguished from transmission by interrupted direct currents. or successive positive .and vnegative 'Gf-pulses -Anotheiiobject of the invention to provide'a `printing telegraph system in'which .fi code combinations, such, for instance as the Well knoivnBaiidot code, may be transmitted .LioV

vide a printing v.telegraph system in which repeated by carrier Vcurrents of two frequencies.

Another object of the invention is to proa counting relay arrangement may be used as a distributor, the counting relays being operated' by a carrier current of one fre- A quency andthe marking signals being transmittdbya carrier current of another freqiieiicy. V

Stillanoth'er object ofthis invention is to provide an 'arrangement whereby the impulsesmaking up a code combination may be from the mairi transmission line over a local loop at a different rate of speed.

. A; of the invent-ion are realized in the arrange-- and out of synchronism with the impulses incoming from the main line. v

The above objects, as well as other'obJects .ment set. forth Ainthe following description, and illustrated in the accompanying draw ing, of which Fig.1 comprises a circuit diagram of the repeater, and Fig.- 2 Aa separate diagram of thel substation. l

Referring tothe drawing, ML designates a main transmission line, over which .printing telegraphv signals may be transmittedl in line oveiaa loop to a local the locall loop by means of..

the usual manner. At a central. oilice the main line terminates inthe usual form of differential. dupleir" arrangement, the main line ML being balanced by an artificial line MN, and a polarized `-receiving rela PR being connected to the main -line'an artii cial line in such a manner as to be neutral with respect` to outgoing transmission which is applied over the circuit 10 to the-main line' at the junction point 11 between said main line and the artificial line' MN. l A

In lorder that signals incoming from the line ML may be, transmitted to a local revERNA-M, or BROOKLYN, NEW YORK, Assronon 'roAMEnIcAN 'i'.ELErHoNE ceiving -station,'a loop L is provided, such Yloop extending from .the central ofiice to the substation, where itis associated with printing apparatus, as described hereinafter.

At the centraloflice, the loop L terminates inl a .well known vfor'm of balanced transformer 12, and a balancing network N. Currents outgoing over theline L from the centralofiiceareapplied to the line L over' a circuit 1'3 connectedto the midpointsof the line wind-ings lof the transformer 12,4

while currents incoming from they line L are inductively applied toa receiving circuit14 associated with the transformer 12.

' The code combinations used in transmitting printing telegraph signals may be repeated from the main line to the local loop and vice versa through an arrangement com-I prising a number of rotarydistributors. .For transmission from the line ML' to the loop L, a distributor D1 is associated with the main line', and distributor D2 is associated distributor D1 1s con-l with the loop. The nected with the polarized receiving relay PR of the main line over a circuit 15, while the distributor D2` is connected to the loop L through conductors 16 and 17 associated with the transmitting circuit 13 through transformers'l and 19 respectively. Since the signals are to be transmitted over the loop L through the agency of alternating carrier currents, two sources 20 and 21, having frequencies of m'cycles and y cycles respectivel may .be applied to the conductors 16 land 1;;

under the control of the distributor D2: Thel code combinations are prefer# i ably transmitted over the mainline ML through the agency of positive and'negative direct current impulses in accordancewith the well known Baudotv code, and in order to translate the impulses incoming from the linellHJ into carier currents for transmission over the loo AL, a set of live olarized receiving relays R1, PE2, PRS., R4 and rlhe distributors D1 and D2 Anot operate synchronously or at the -same speed, the syst'em being so arranged that the distributor D2 may rotate at a speed equal to or greater than that of the distributor l)1 so long as the speed of the distributor D2 shall not be greater than approximatelyy trol the circuits of the printer magnets M1 twice the speed of the distributor D1.

In order to repeat signals from the loop L to the main line ML, a start-stop distrib utor l)3 is associated with the main line ML, and a start-stop distributor l)4 is associated with the loop L. The distributor D4 is associated with the loop L over a circuit 22 connected toa contactof an alter- -nating current receiving relay AR, connected in a tuned bridge of the circuit 14. The circuit of 'the relay R1 is tuned A.tothe frequency and in order to' prevent .feurrents of frequency y from being transmitted.,

to the relay AE1, a .filter arrangement F is included` in the circuit 14. Thisfilt'er' 30- 'may' be of any `well known type, s uch, for i I disclosed in U. AS. patent' to George instance, 'as a filterof the general .character i, Campbell' 1,227,113 issued May 22, 1917.

.into positive and` negative impulses forv in'gfprinting apparatus is associated with The distributor D3 is associated with the inain line ML through the conductorl() previously referred to.- A I- Distributors l)3 and D4, like the distributors l)1 and D, already described, need f1 not rotate at the samev frequency, as the circuit is so arranged that the signals will bel properly repeatedif the distributorrD rotates at a frequency equal \to or greater than that of the distributor D3 so longaszit does not exceed, 'about twice the speed of the latvter distributor. In order to translate the carrier signals received fromthe loop L transmissionover the line-ML asetof five olarized relays PR1,'PR2, PRS', PR] and R5 are connected to the receiving :seg-

ments of the distributor D4.

At the substation of .the loop L a receivthe loop through-a counting relay distributin'garrangement. The receiving apparatus of the printer is indicated schematically as consistin'clr of a set of five selecting magnets M1, M "M M4 and which under the .well known manner. t

printer are not shown, as the printer may be control of the counting relays respond to the individual elements of the code combination and control the printing operationin a The details of the of anywell known type -capable of responding to the Baudet code. The transmitting portion of the -printer is shown schematicallays.

ly as consisting of' a set ofiivel keylzsoard-l contacts numbered l to 5 vinclusive for trans-Y `mitting various code combinations to the loop L under the control of the countino' re- A common keyboardY contact is also providedfor initiating the transmission ofthe code combination in a manner hereinafter descrlbed.

The counting relay arrangementfcomprises-a series of five .locking relaysnumbered` 1 to 5inclusive, and 'ajseries. of five switching relays'numbered lto 5 inclusive the last set of relays being arranged to con- L. 4This bridge is tuned to be responsive to currents of frequency y and the function ofthe currents supplied by the source '21 at the central office is, therefore,'to supply a c aigrier current for controlling the stepping or" successive action ofthe counting relays. The actuationiof the-ffprinter. magnets, on the other hand, is controlled by a second "alternating current relay Alt-,which is included i'n altu'nefdvbridge across the loop L, said tuned'bridg'e also havin serially .in- 'serted therein thecommon key voard contact `K and a break key BK whose purpose will loop L froni-'thasource 20`serve to control .be more fully. described later."A This'bridge is prefer-ablyl tuned to-currents o f frequency;A fav, so thatv'thecurrents transmitted overthe'f-flol the actuationfofthe printermagnets and, as

willbegdescribed'later, to cause the response of the receiving elements of the repeater ap-l l A105" paratus at'thc central station in responseftothe actuationV of the keyboard contacts.

Further details of the apparatus will-now be clear from a description of the Ifoperation,

which is as follows: l In a printing telegraph system `'employing start-stop distributors, seven `impulses are transmitted for I each code' combination. These seven impulses may comprise a posi- 4tive starting impulse followed by llive-mrI pulses whichmay be variable. combinations ofposltlves and negatives for determmlng the character to be printed, these tive impulses being. followed by a negative stop impulse. In practice, the negative stop impulse 'will be continuously transmitted over the main line ML from a-distant station so long as the distributor at the distant station pulse the polarized receiving relay PR holds yisnot bein operated intransmitting characters. .During the continuance of this imconnected -to'negative battery. 'AS soon as the distributor Iat the distant station is'released, a positive starting impulse-is transmitted';` and the polarized relayPR shifts -tact of the relay PR, over thev segment 23v its armature't'o w contact which is connect? j ed to the positive battery, so that a circuit is closed from positive battery over-the conof vthe upper ring ofthe distributor D1, through the brush and over the segment 24- of thelowerring of the distributor through the release magnet RM1 to negative battery.

, The release magnet is thereby' operated and releases the brusharm of the Adistributor so that the brush passes successively over the -five impulse segments of-the lower ring of .impulse is a positive impulse, it being .DT ytor D1 passes over-theg--succeeding segments withl the first segment of the distributor and willA shift its armature toits upper or lower-'fcontact.

If 'the received assumed that positive impulses are marking impulses, the armature of the. relay PR1 will be shifted to its upper contact, which is connected to the source 20,v so that. an alternating potential of frequency :v will be connected from' the source '2O over the. upper contact of the 'relay PR1 to the first segment of the lower ring of the distributor Similarly, as the brush of the distribu- 2, 3, 4 and 5, the corresponding polarized relays are operatedinVVV accordance with the chaia'ctendetermining impulses which are Y being transmitted over the main lineML at that moment.- Let us assume thatthe first, third and vfifth impulses following thenstarting impulse are positive, and thatythe second and fourth are negative spacing impulses;

accordingly the relays PR1, PR3 and PR, will shift their armatures to their upper contacts, while the relays PR2 and PR1 will shift their armatures to their lower contacts, providing the several armatures are not already resting in the positions indicated, it

being understood that the arma-tures will remain inl any position lto which they are shifted until they are moved to the opposite position by anV opposite impulse. An alternating potential of frequency m is now con-v nectedover contacts ofthe first, third and fifth polarized relays to the first, third and fifthv l,segments of the lower ring ofthe distributorD2-` f At the instant the brush arm of the distributor D1 passed-between the third and fourth segments of the lower ring, a circuitl was closedl from ground over segment 25, the brush arm vof the distributor, segment 26, over conductor 27, through the .windingof start magnet 28 of distributor D2 to bat- 'terv. The start magnet 28 is energized over assalti? -time to pass from segment 25 this circuit, and releases the brush arm of the distributor D2 which moves over the face of the distributor and transmits the carrier -currents corresponding to the code combina- Y tion in a manner to be described presently. It will be noted that the circuit of the start magnet 28 was closed at about the time the throughone-half of its revolution, so that the distributor D2 is not released until the distributor D1 has passed. through one-half of yits cycle.v The vdistributor ,D2 ,cannot 'be permitted to rotate slower than the distributor D1, but if it rotates at the's'ame rate it lwill be observed that as the code impulses come in fromthe line ML and are stored up-on Athe polarized relays PR1, PRwletc., the firstV stored impulse will .not be trans- This impulse will:--mitted to the loop L-by. the. distributor D1- u'ntil the third' impulse, exclusive of the startingimpulse, has come in from the line after :passing over the fifth segment passes 'on to the starting segment 24 where it'en-l gages with the latch controlled lby the release magnet RM1. 1 The release magnet is at this moment cle-energized because at thisv brush arm of the distributor D1 had passed `MLL The brush arm of the distributor D1,

same instant a negative stop impulse is being ing impulse of' a new code combination immediately follow this stop impulse the dis -t-ributor .will be released to set .up a new code combination.4 -Vhile the distributor impulses of the code combination'previously set up, it will 'be noted that if the two dis- -received over the line ML. Should a startico f tributors are -rotated at the same rate of speed, Athe impulses stored on the. first three relays will have been Vtransmitted by thedistributor D2 beforethe distributor D1 is released the second time. In other words, the distributor D1,'while several im ulses behind thedistributor D1 *asA regars the code combinationv being transmitted, will be several'impulses ahead of the distributor D1 with respect tothe succeedingcode combination. Should the distributori), rotate at a slower-rate than the distributor D1, however, the brush arm of the latter might overtake that ofthe former and change-'al combination previously setup on the polarized. relays PR1 to PR5 inclusive before said vcombination had been completely transmitted by the distributor D2. l

It is also possible to operate the distributor D'2 at any speedgreater than tha't of the' i distributor D1 -so long' as the distributor D2 brush arm of the distributor D1.has had segment of the lower ring.

overthe fifth If the speed does -fnot rotate so fast that its brush arm .125-

will pass' over its fifth segment before the" this, one or more impulses Lstored up by the4 upper contact of polarized relay PRl/,rst

` ,distribuer n, migrate st infer@ the aistributor D2 had an opportunity" to trans' mit tlieinitoI the loop L. The distributor D2- ,maybe operated at any speed vbetween the .two limits above indicated withoutmutilating the signals tobe repeated from the main line to the loop. This is advantageous. in practical operation, since 1t becomes unnecessary to vmaintain the distributors D1 and D2 insynchronism, an'd the operations of Stor'- ing up impulses by the distributor D1 and fof transmitting the stored impulses by the distributor D2 become independent in point ,'.Wlien the brush arm of the distributor D2 is'at rest, a'circuitis closed from genera-` through theprimaryA winding of the trans-v vtor 2Q over the stop 'segment 29-of the lower ringof the distributor. D2, brush and ring of said distributorand over conductor 16 former 18to ground. Currents of frequency are,'th`erefore, impressed upon the circuit 13 yand are 'transmitted over` the loop L to maintain the alternating current 4relay AR3 atvthe substation inoperated condition.

Upon 'the release "of .the brush 'arm of .the distributor D2l byl the energizatio'n of the i magnet 28 as alreadydescribed, the brush.

arm passes from the stop segment 29 to the. start segment 31,'thereby opening the cir:

cuit previously described 'from the source 20.

The currents of frequency mare -no longer transmitted over the -loop L, and the relay .AR3 is accordingly released. As the brush arm of the distributor D2 passes over the first segmentgof the ring 32, f'afcircuit is closed from generator 21 over said first segment through the brush of the distributor.

and ring 33 thereof, and thence over conductor 17 through the primaryvwinding of the transformer 19 to ground.v Alternating current of frequency y is now transmitted to the circuit 13 and overthe loop L operating the `alternating current relay AR2\atthe'substation.; Relay AR2 closes a circuit from. battery .over its front contact, over the right hand back contact ofgcounting relay V'4,.right hand back contact o-f counting relay I tributor D2 came in'contact with the first segment of the ring 32 of the distributor,

. the brush arm. passedover the first contact of the lower ring'of said distributor, thereformer 18'. yCurrents ofv frequency are,

through fthe vwinding of magnet M, to

backcontacts of counting relays 5 and 3,

by closing-a circuit from source 20 over the rsegment ofthe lows: ring of distributor D2,

brush of the distributor, ring 3Q, over conf ductor .16 and through the primary of transtherefore, transmitted over the loop L to operatefthe relay AR, an instant after the relay AR2 had been operated. Relay AR3, therefore, transmitsA a 4marking impulse to the printer magnet M1 from battery over the front contact of relay AR3, over the upper back contacts of vrelays 5 to 2 inclusive,

over the upper front contact of relay 1', Y I

ground.

As the brush arm passes from the first f to the second segmentiof the ring 32 ofdisT 4tributer D2, the circuit from the generator 21- is opened, and currents of frequency' y 85 are no longer transmitted over the loop L. The relay AR2, therefore, releases its armature and a circuit is nowr closed from battery over rthe back contact of said relay, and over the vfront right handA contact of counting relay 1 through the windings of countingrelay 2 and switching relay 2 to ground. Relays 2 and 2 are locked up over the right hand. back .contact of slow .release irelay 6 and the circuit controlled by the relay AR3 is shifted by the switching relay 2 to the magnet M2 over the upper front contact of saidrelay 2. In the case of the assumed code combination being trans- 100 mitted, .it will be remembered that the .second impulse of the five character forming. impulses was a spacing impulse.- The polarized relay 13R-2, therefore, shifted its arma- -ture to its lower contact.- Consequently, as 105 the brush arm of the distributor D2 passes over the second segment of the lower ring,` no circuit is closed from source 20 to the transformer 18. Relayv AR3. at the substation is, therefore, A(1e-energized during the 110 period that the relay AR2 is vie-energized, f

and consequently the' magnet M2 of the p'rintervis not operated. Asthe brush arm passes over the third v contact of the ring 32, currents of frequency 1.15

y are transmitted over the loop and operate' .the relay -AR2 -to close a -circuit over the righthand back contact of counting relay 4, and right hand front contact of counting. relay 2, through the windings of relays 3129 and 3. "These relays .are energized and' lock'up, the relay 3 shifting the connection controlled by the relay AR, from the printerA magnet M2 to the printer .magnet M3. The third character-forming impulsewas .a positive impulse, and consequently currents of 'frequency .fr are transmitted over the third segment of the'lower ring of .the distributor through the loop L2, thereby energizing the relay ARB. The-latter relay closes al 13 circuit loverithe lupper front contact of the switching relay 3 for the magnet M3, there-` by operating said magnet.

In a similar manner the relay AE2 is deenergized as the brush arm of the distributor passes over the fourth segment closinga circuit forthe relays 3^ and 4, said relay AE2 being energized as the brush arm passes'over the fifth segment to operate the relays and 5, .The relays 4 and 4 Were energized at the time the fourth characterforming impulse was being repeated to the,

' loopL, and as this impulse Was a spacing impnlsethe magnet M,t was not operated.

. The .fifth impulse being la marking impulse,

the magnet Miwas-energized by the. relay vAE :jafter the Vrelays 5 and 5 pulled up their armatures.ff-v l Immediately after the brush arm of the distributor passed off of the fifth segment of the ring'32, it came tofrest by'engaging 4'the catch controlled by the starting magnet 28; At the same time the circuit of the generator 21 Was opened so that cur'- rents'of frequency y are no longer transmtted to the loopL. The relay AE2 at the substation is, therefore, releasedj and come' .pletes af circuit from battery over itsback contact, right .hand front contact of counting relay vv5 and through the' Winding of slow release relay 6. Relay 6 upon being energized closes at its left hand front conf, tact a circuit for the relay or magnet '(not shown) which sets into operation the print.y 1' ing mechanism selectively controlled bythe printer'mag'nets M1 toM5 inclusive to-print the selected character in a manner Well un- I derstood. The relay 6 atitsright handk conrelay-51E3 at the 'substation in energized' tact opens the locking circuits for the counting relays 1 to 5 inclusive, the switching re'v lays 1. to 5" inclusive, so that the circuits of 'these relays are restored to normal ready to receive' a neu7 code combination. j The brush arm of the distributor D2 upon coming to vrest causes currents of frequency to be transmitted over the loop L in a manner .already described, thereby maintaining the condition. In case it is desired .to transmit printing signals from the vsubstationy over theloop I 'L to the main line ML the keyboard transmitter will be operated by pressing .the key correspondingto a desired 'character in a well. known manner. In'response to this operation, certain of the keyboard contacts 1 lto 5 inclusive will be operated,` andthe common keyboard contact le will be opened.

1` Let `it be assumed that the first, -third andv v fifth keyboard contacts are operated. In the normal condition of thecircuit with the fcontact A of lthe key It closed, the loop4 L is just ybalanced l by the network N, so that` currents 4vfof' frequency transmitted `from the source over the circuit 16 lin the vmanneralready described, divide equally between the loop and the artificial line withcircuit 14 and througlT the filter F to thealternating current relay AE1 which visin a timed circuit responsive to rcurrents of frequency '00.1 Eelay AE1 upon being ener. gized, closes a circuit from positive battery over its front contact, over conductor 22, ring 34 of the distributor D4, brush arm and segment 35 of said distributor, through the Winding of `starting'magnets 36 and 37,0f` distributors D4 and D3 respectively, over the segment'38, brusharm and ring 39 of the latter distributor, and thence over conductor 40 to negative battery. Starting magnets'36 and 37 are energized over/the-A circuit above traced, and release the brush arms of distributors D3 and D4, which.pro' ceed to pass overthe various segments of the tWo distributors.v f i y Upon the brush arm of the distributor D4 passing on to the rst contact ofl its ring 41, a circuit is closed `from source 21 over said segment, the brush and ring 421of`distributor` D4 and thence over vthe conductor 17 through the' primary/Winding of transl former 19 tol ground. Currents fof fre-l quency y are'tlierefore, transmitted over the loop L and operate the relay AE'2 which closes the circuit of the'counting relay 1 and switching'relay 1 4in a manner already declosed' over` the lower back contacts' 'fof switching relays 5fto 2 inclusive, over the lower 'front contact4 of switching relay 1 and the first keyboard contact. The loop-L is now balanced and currents of frequency are no longer-transmitted tothe circuitl14. The relay'AE, is'accordingly de-energi'zed. '1`

At this moment the brush arm of the dis-4 tri-butoris passing over the first segment of "the lower ring ofthe distributor D4, and?" consequently: the circuity is closed from nega-- tive battery over the back contact of -the relay AE1, over conductor 22', ring 34, brush arm and first segment of the distributor D,

`tothe Winding of the'polarized relay PE1 to ground. Eelay' PE, isenergized-` toy shift its armature to its lowercontact'if not already in this position, thereby connecting positive battery to the first segment" of the lower ring of distributor D.

The brush*v arm of -thevdistributor D4 now passes from the first segment of ring 41 to the secondsegment, so that current of' fre. quency y is`v no longer'trans'mitted to the looplL. Relay-AEZ, is, therefore,.de`eiier gized, andoperates counting i relay 2 and switching relay 2' The' loopfthrough the relay AE, is, thereby shifted lfrom the r'st the distributor D4 passes overthe secondsegment ofthe lower ring operates the polarized relay -PRZ to Ashift its armature to 'its upper'negative contact if nota'lready in this position, thereby placing negative'battery onthe 'second segment of the lower ring of the distributor D4.

Ina lsimilar mannerthe relay AR, is al` ternately energizedand cle-,energized as the i brush arm of the distributor D4 passes oyer D4. AS, ,the brush of the distributor n4 lea'se relafev over. a circuit already de? keyboard relay (not shown), which unlocks' the remaining segments of the ring41, and under the control of the countingandl switching relays the controlA of theloop -through the relay AR, is transferred successively to the remaining keyboard contacts so that the remaining polarized relaysPRs to PR inclusiveare operated to connect positive battery tothe third and fifth segments, and negative battery to the fourth segment of the'lower ring of the distributor .passeso of the' fifthsegment of the ring 41 the frequency y is no'longer transmitted over, the loop' L and therelay AR,Z is deenergi'zed, thereby operating thev slow re- 'scribed Relay 6, upon being energized opens the locking circuits 'ofthe counting relays and switc'hmg relays, and at its'right rlia'nd front contact .connects battery-to the the keyboard contacts and restores them 'to normal ready for the setting up of another vcode combination. 'lhe'fbrush arm of the distributor D4 in thef'meantime has' come tov `rest in engagementy with the catch of thel release. magnet 36;? 'f 5 It will be remembered that the brush arm*v .of .thedistributor D3 was'released at the' same instant as the brush arm of the dis'- tribut'or D4, and consequently has been pass? ing-over the segmentsof lthe variousrings at the same time that the operations above described weretaking place. With the bril-sliv i arm of thedistributor D3 in its'norml condltlon, negative battery. is connected over the segment 42 ofthe lower ring, brush arm and ring 43 ofthe distributor D4 and'over conductor 10 tothe main line ML, thus trans-V mitting the' prolonged stopv impulse Ato'i the pulse to release the distributor at the distant` i station. As the-brush arm'passes `overfthe rst, second, third,fourtl and fifth seg# main line. '.'As soon as'tlie brush arm of l' i distributor D3 passes from-the stop segment 42 to the start segment 44j, positive battery is connected to the main line 'over a similar circuit, therebytransmitting the startl imments of the lower ring, the five characteri forming impulses are transmitted under the control of the polarized relays PE1 to PRS inclusive, thereby transmitting 'a characterset up by said relays.

The distributor D3- may rotate forming combination corresponding to thatl at the same speed as the distributor D4, in which case' the impulses set 'up by-theopolarized relays w ofthe-latterdistributor will be-transmitted immediately after they are Aset up .by the distributor'D3, which1 will be-mov'mg'in apsv proximate synchronism with the distributor- D41, The' distributor ID3, however, cannot rotate faster than the distributr'D4 asin this case itmight complete a full revolution and .pass off of its fifth segment before tl1e fifth vcharacter-forming impulse had been set up on the relay PR/Q thereby 'Iielslultng`- in a mutilation of the signal. tributor D3'on the other hand, may rotate' at` any desired speed slower than that ofthe distributor'D4 as the .latter cannot bereleased in response lto the setting up of a new code combination at the keyboarduntll' the.

brush arm of the distributor D31'hascome to I rest, .for it .will be notedthat tlie circuit of v the release magnets 36 andl37 pa sses over the'initial segment 35 of the distributor-D14 and the initial segment 38 of the distributor D3 in series, so that both brushes must be in-` normal position before either brush can be I f released. 4It is l'not desirable, however, to

have the. distributor D3 rotate less thanhalf -ieo the speed of the-distributor D4, since `in practice distributor D4 will been the same shaft as the distributor-'D2- vandwhenreleased `will rotate at thevsamc speeds 'the latter, and consequently to lhavethe dis- 4.; i 'tributor D rotate at a'slower speed that* inc ic'ated`r would' unnecessarily slow.v 4 down the transmis'sioni.of''signals..v Further-f" more, in-.practice, distributor D4. would" be onthe. same shaft fas the distributor D1, and

would rotate at the'` same speed, so that the same .relativeggdiierence in speed -between the distributors Da'fand; lD4 exists as between thefdistributors D1 a'nd DZ;

so that4as .soonias currents ofj'freqefncy are transmitted tothe circuit :.134 at' any periodin the rotation of the'distributoriD'Z Should'jthe-operator-at the 'substation del sire for any reason to transmit ata" time when-signals are. being received'romthe '-main 4lineML', the *break key BK willjbe operated, thereby unbalaribing the looprL,

i these currents'will be transmitted to the cir. v

cuit '14 due, tothe unbalancedY ondition,'

therebyfoperatingthe relay.AR',; `Sai5d re lay in shifting its armature to its positive.'l

contact closes a, circuitv over.y conductor 454' for the polarized relay PR which shifts 4its armature toi its lower contact, thereby com .'pleting a circuit from the source 2O over said iso contact, and over conductor 16 to the pri# 3o negative 'characteri mar lWindingvfof the transformer 18 inde- .tive battery .will be applie ing the printer at the `tlie mainline ML to 'the break signal.

pen ently of the 'distributor D2. Conse' quently, currents of frequency w will be transmitted to the circuit-14 to maintain the' relay AE1 operated as long as the break key is' held open` and theloop maintained unbalanced. .The opening of the circuit. of, theA relay AR, bythe break key will', of course, mutilate .the code combination at that'moment being set up'by the counting and switching relays, as Well as any further code combinations transmittedover the main .line before the. distant operator o bserves v The `actuation of the relay AR, above de-I scribed also completes a circuit previously traced for the releaserelay 36 and 37 ofthe distributors D4 and D3. The brushes of the. distributorsD3 and D4 are accordingly released. and rotate over their segments.v As' the break key maintains theloo'p'L unbalanced, and relay AR, operated, positive impulses are transmitted to all five of the polar relays PE1 to PR5- inclusivel as the brush arm of the distributor D4 rotates, andnegad to the live character determining segmentsof the" distributor D3. Consequently, instead of a continuousnegative impulse. a. code combination. consisting of'a positive starting impulse, five forming impulses' andA a is transmitted overl the distant station. This code combination may be utilized at the .distant station lto operate a signalv suchfas a lamp in a Well known manner, or, by prin'ting a special character, or by merely operatdistant station, to infdicate to the operator at such stationy that the operator ,at the substation desires to n break in and transmit.

negative stbp impulse tion above described will be transmitted as long as the break key BK is held open. .The operator at the local station upon restoring the break key, and observing that the local printer is no longer operating, will understand that the distant operator has stopped sending and the local operator may thenl y ing telegraph signals roceed to transmitin the regular manner. It will be obvious that-they general principles herein disclosed may be -embodied in many other organizations widely different from those illustrated, without departing from the 'spirit Aof the invention, as defined in the following claims.

What `is claimed is:

I' L'Ina printing Itelegraph system, a cirgraph' signals .by

another circuitfor the transmission of printby alternating carrier4 currents, and means rect current impulses of ac'ode combination incoming over said first circuit into a code combinat-ion comprising a group of intervals The code vcombina- ",m'ay be transmi for translating thedi-ff' Sonie of Whiehitorrespondfto marking signalsand others of'whicli correspond to spacy ing signals, means togtransmit. alternatin currents of-one: frequency over said seconc circuit "during Aalloi the intervals corresponding to one 'type' of signal only, and means toA transmit -alternating currents of another frequency'. oyer, 'said' circuit *during certain of Said intervals ,regardless of .the typeof signal which they represent. l 2. In a 'printingltelegiaphsystem, acircuit for the transmission,of 'linting telegraph signals by, meansof a. audot code, another circuit f'rj the transmission of printing `telegraph, signals. by alternating carrier currents, and means for translating the Baudot,` code eomhiiationgiincoming `from said first circuit.intoacarrier current code conibination comprising a\.group of intervals some', of 'which correspond to marking signalsaiid Others of Which correspond to spacing"si`gnals, means to transmit alternating currents of one frequency over said second circuit., during all of the intervals corresponding to one typeof signal only, and means to transmitalternatingcurrents of an- Y -otlier frequency vover v'said circuit during `fceiving distributor comprising a series of ,countingrelaya means whereby said counting, relaysl maybe successively operated in response to they-transmission oficurrents of Vone:frequency from ra distant station, and means responsive another frequency .transmitted from they dis'- tant station `to selectively operate the printer under the ontrol of the counting relays.

4. In a printing telegraph system, a transto groupsjof .oscillations of r mission circuit, a receiving printer associated therewith, counting relays for controlling the operationl of said printer, and selective devices associated With the printer and having `their circuits individually contro'lledby the counting relays, means for successivelymoperating the counting relays Ain response to the transmission of currents ofone frequency from the distant station, and means responsive-to .the transmission of groups of oscillations of another frequency from the distant-station to selectively operate said selective'` devices as the circuits arejelosed by the counting relays.

5. In a printing .telegraph system, a' circuit over Which printing telegraph signalsy 'tted by the Baudet code, anover which printing telegraph signals-may Abe transmitted by means of car-i rier"eurreiits, a receiving printer associatedu ivith said-second circuit, counting relays for controlling said printer, means at the junction point of said circuits fortranslating the Baudot code into alternating currents of. not more than two frequencies,` means p whereby said counting relays aresuccesc sively operated in response 'te..the transmission of alternating f currents of one frequency, and means respons1ve to groups of oscillationsof the other frequency for selectively operating saicl receiving printer under the control-` of the counting relays.

6. In a'printing telegraph system, a circuit over which printing telegraph vsignals 'may be'transmitted by means of the Baudot code, another-circuit over. which printing Vtelegraphzsignals mayy be transmitted by `ond mentioned circuits for translatin .means of'alternating' currents, a 'receiving' more than twofrequencies for transmission.

over vthe loop, means responsiveto the trans-- mlsslonover the secondoircuit ofjalternating` currents of .one frequency successively. operating the counting relays .and means re.

sponsive vto the transmission of groups of oscillations "of the-otherf'r'equ'ency, for"I selectively operatingsaid selectivevdevices as the circuits: are completed. by counting .7. Ima-printing telegraph system'ftwo transmission circuits, 'means for repeating from oneofsai'dcircuits towthe'bther, 'said4A means comprising ari- Y intermittently-rope# d l .main transmission line and local receiving ating distributor associated'with one of saidj circuits andan intermittently operating distributor associated with the other off-said circuits at'the junction-point of said circuits,

one. of said distributors functioning to-register code Ycombinations transmitted over one of said circuits, andthe other distributor functioning to transmit,saidy registered combination to'fthe'. otherfcicuit, said distributors being 'operated non-synchronously. 8. In. a printing. telegraphv system, two

transmission circuits; me'ans for repeating'-y from-one of saidcircuits to the otherksaid means comprising an intermittently -oper'at'- ingl distributor associated', With oneiof said circuits-f and? an intermittently `operating distributor associated with the 'otherA osaid c :prcuits at thezjun'ction point of saidcircuits,y

oiejof" said distributors functioning to reg- Acode"'fficombinations transmitted "over 'one':of-saidcircuits, and the otherdistribui tor,- functioning to i transmit said registered' combination to theothe'r circuit, `saidj'distributors bein "operated at different speeds.

l,19. inl aprintig-,telegraph system, two

`transmission'fcircuits, 'means for repeating from oiiepof sa`idfcircuits to the other, said -means ,comprising an intermittently operating distributor associatedwith one of said circuits and an intermittently operating distributor associated with the other of said circuits at the junctionpoint of said circuits,

'. one of said distributors functioningl to register code combinations transmitted over one of said circuits, and 'the other dis-V tributor functioningto\transmit said registered 'combinationto theother circuits, said distributors being operated during .succes- 4sive but partially overlapping intervals for repeating the same signal. i

, 10. In a printing telegraph system, a

main transmission line and local receiving loop, means for repeating signals from said main line to; said loop and vice versa, said-A Aso means comprising a pair of intermittently operating distributors associated With-the f main line and a pair of intermittently f operating distributors associated with the 1 l loop at the junction point of said main line and loop, one of the distributors, associated functioning to vtransmit lsaid registered signals to the loop, the other distributor associated with the loop functioningto register' signals transmitted over vthe loop and a co'rl responding distributorassociated with the main line functioning to -ltransmit said last mentioned registered lsignals to the main line,"y saidj ldistributors associated with the` main line being operated non-'synchronously :with `rgspect-.to those associated with the local loop. y

1p1..A In -a printing telegraph system, `a

loop, 'mea-ns for repeating signals lfrom said main hne to said loop and vice versa, said means comprising a pair of distributors associa-ted vWiththe main line and apair of l -distributors associated with the loop at the l junction'point'of said main linel and loop,

one ofthe distributors associated with' the main@ line functioning to register signals transmitted thereover, a corresponding dis- A tribut'or associated Withy the loop functioning-to transmit the registered signals to the A loop, the 'other distributor associated-With'` Athe-loop functioning to register signalsA transmitted over the loop and a corresponding vdistributor associated .with `the main line functioning to transmit-registered sig-` nals to the mainline, saidv distributors associated. with the main line being operated at al diiferentspeed from those associated with-the local loop.

Al2. In' a` printing loop,rmeans for repeating signals from said lao - Y telegral'ih system, a l' main transmission line and local receiving y main lineA to'sa-id lloop and lvice versa, said* .l means comprising 'a pair ofintermittentl'y" operating distributors associated with the mainline and -a pair of intermittently operating distributors associated 'with' the loop at the junction point of said main line land loop, one of the distributors associated with lthe main line functioning to register ciated with the loop functioning to'registcry signals transmitted over the` loop and a corresponding distributor associated With the main line functioning to transmit registered signals to the main line, said- -distributors associated With the main line and local loop being operated at successive intervals with respect to each other. K

13. In al printing telegraph system, a main line over which printing telegraph signals may be transmitted by means of current of one character, a local loop over which printing telegraph signals. may be transmitted by means of current of another character, and means associated with said main line and loop at their junction points for translating the signals transmitted by one l'character of current into currents of Vthe other character, said means comprising a distributorassociated with the main line and a distributor associated with the loop,

one of said distributors controlling the circuits of the other.

14. In a printing telegraph system, two j transmission circuits, means for repeatin from one of said circuits to the other, sai

means comprising an intermittently operating distributor associated with one of said circuits and an intermittently operating distributor associated with the other of said circuits at the junction point of said circuits, one-of said distributors functioning to register code combinations transmitted over one of said circuits, and the other distribu- Vtor functioning to transmit said registered combination to the other circuit, and means to operate said distributors non-synchronouslybut with their periods vof operation partially overlapping.

y In testimony whereof, I have signed my name to this specification this 6th day of April 1920.

GILBERT S. VERNAM.

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