US1286351A

US1286351A - Electric selective system.

Info

Publication number: US1286351A
Application number: US21664718A
Authority: US
Inventors: Howard L Krum
Original assignee: Individual
Current assignee: Individual
Priority date: 1918-02-11
Filing date: 1918-02-11
Publication date: 1918-12-03
Anticipated expiration: 1935-12-03

Description

H. L. KRUM.

ELECTRIC SELECTWE- SYSTEM.

APPucAUoN FILED MAY 31, 1910. RENEwED FEB. 11. 191s.

Patented Dec. 3, 1918.

2 sH'EETs-SHEEI l.v

H. L. KRUM.

ELECTRIC SELECTIVE SYSTEM.

APPLICATION FILED MAY 31, 1910. RENEWED FEB. 11.1918.

1286,351. Patented Dec. 3, 1918.

2 SHEETS-SHEET 2.

' UNITED sTATEs PATENT oEEioE.

HOWARD L. KBUM, OF CHICAGO, ILLINOIS, ASSIGN-'OR T0 MOBKRUM COMPANY, 0F CHICAGO, ILLINOIS, A CORPORATION.

ELECTRIC SELECTIVE SYSTEM.

Specification of Letters Patent.

Patented Dec, 3, 1918.

Application led May 31, 1910, Serial No. 564,120. Renewed February 11, 1918. Serial No. 216,647.

T 0 all whom t may concern.'

Be it known that I, HOWARD L. KRUM, a citizen of the United States, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Electric Selective Systems, of Which the following is a full, clear, and eXact description.

The invention relates to selective telegraph systems applicable for the operation of printing telegraphs and the like, and seeks t'o provide an improved method and system by which the signals or characters of a message can be rapidly transmitted from one station and received or recorded with certainty at a distant station, and which is not liable to be affected by the di t'- ferent conditions and disturbing influences to which the telegraph line may be subjected. A further `ob] ect of the invention is to provide an improved system which can be duplexed or employed to transmit selective signals in opposite directions over the same.t

line circuit. The invention consists in the features of novelty hereinafter set forth, the preferred arrangement of the circuits of the system being set forth in the accompanying drawings', and the invention being more particularly pointed out in the 'appended claims.

Figure 1 is a diagram of the circuits 'in one arrangement of the improved system. Fig. 2 is a diagram of circuits as arranged for the yduplex transmission of the signals. Fig. 3' is a diagrammatic representation of the transmitted impulses and of the operation of the selecting devices or relays.

In accordance with the present system, the signals or characters are distinguished by different permutations of a definite number of impulses of opposite polarity. Preferably, there are five impulses in each permutation and the arrangement of circuits shown is designed to employ five impulses in each permutation and, as Well known, there are thirty-two permutations of'positive and negative 'impulses when there are five impulses in each permutation, so that thirtytwo different signals can be transmitted. By employing an additional sixth impulse in each permutation, the number of signals can be increased to sixty-four. For the ordinary operation of a printing telegraph apparatus,

thirty-two permutations are suiiicient. How- Which is not varied but is always of the same polarity. For example, if the line circuit is normally connected to the negative side of the battery, the starting impulse for each combination or signal Will be positive. It the line is normally connected to the positive side of the battery, the starting impulse of each combination will be negative. The remaining live impulses of each signal will form the thirty-two permutations to effect the desired selective operation of the receiving circuits.

The present system has been applied to an improved transmitting and receiving apparatus devised by Charles L. Kram and myself and set forth in a U. S.v Letters Patent No. 1,232,045, dated July 3, 1917. @ne arrangement of the present improved selective system was set Vforth in the application referred to in order that the invention therein set forth could be clearly understood. The present improvement is, however, applicable to other forms of trans-` mitting and receiving apparatus.

In some respects the present improved arrangement of transmittmg and rece1ving or selecting circuits and relays may be considered an improvement upon an electric telegraph or selective system devised jointly by Charles L. Krum and myself and -set forth in U. S. Letters Patent No. 1,199,011,

dated September 19, 1916. 1n. certain other f ybranch conductors are connected respectively to the normally. disengaged or front contacts of aV set of live transmitting switches b1, b2, b3, b4 and b5, arranged to be operated by a set offtransmittiiig` relays B1, B2, B3, B4, andBs. In the arrangement shown, the normally engaged or backcontacts of the selecting switches or pole changers A v changers A are operated in different combinations, preferably by means iof a setof finger keys, that is to say, only one of these keys t) is shown, but it will be understood thatthere isone key for each signalfor permutation to be transmitted and that each keyis provided lwith a series of projections C1 which are arranged to operate .the poleI changing switches A and select the permuta'-` tion that distinguishes the signal or .character represented by the key.

When the systemA is arranged for transmitting, the line circuit extends fromr the transmitterv switch b1 through the several transmitter switches b2, b3, b1 and in series, each transmitter Switch being connected to the normally engaged or back contact of Ithe next switch -in the series by a conductor 9. The last transmitter switch b5 is connected by a conductor 10.to the back contact of a normally closed' unlocking switch b which isarranged to be shifted to open position by a relay magnet B, This switch is connected by a conductor 11 to one of the poles of a manually shiftable 'switch.D, the other pole or contact of which is connected by a conductor 12 to the ground or to a return wire leading to a distant station. The switch D is connected to -one end of the main line wire or conductor 13 which extends therefrom throu h opposite coils 14 of a polar-l ized line relgay D1, and thence to the distant station.

'- Each of the transmittingl relays is arranged to operate a` norma open switch ceeding'magnet or relay of the set.I The contac-t of each switch bs is connected to a. y coil ofthe neXt succeeding relay/ by a conductor 15 and the switches themselves arev connected by a common conductor 16 to the normally engaged or back contact of an unlockingl switch which is operated by the -unlocki'ng relay or magnet B6. The conductor 16 also .leads to the first transmitter tions for letters patent above referred to, -is

arranged to lock the selected key inI shifted i positlon and prevent the operation of the 110l other keys, until the transmission' of the signal corresponding to the depressed key is completed. For this purpose each keycarries a spring-held latch e1., which, when the vkey is depressed, is forced by a xedcam I5 plate e2 beneath -a universal bar 3. Thel ba which controls the circuitof the neXt'sucv magnet Bv1 and to a locking magnet This ylocking magnet, as described inthe applicauniversal xbar is operated by'the magnet E and thecircuit of the latter 1s closed whenever any key is partly depressed.

The /other or normally disengaged con- -tact of the 'switch b1 is connected by a con-` 70 ductor 17 to the coil of the magnet B8 and the switch itself is connected by a conductor 18 to a switch a. This'switch is opervated together with the pole changmg vto one pole of alocal battery 20. The other pole of the battery is grounded or *connected to a suitable return wire.

The local battery wire 19 has several v branches, all of which are indicated by heavylines in the diagram. One branch of this battery wire is connected to a normally open 'switch b9 that is operated by the first transmitter relay B. The normally disenl gaged contact of this switch is connected to theconductor 18 which, as stated, leads tothe switch a. The -transmitter relays, the unlocking relay'B6 and the magnet E are all connected on one side to the ground or ,by a suitable return .wire to the local bat- In operation, the switch D is shifted to connect the conductor 11 to the main line wire 13 at the transmitting station, and at the receiving station, the corresponding switch will be employed to ground the main line wire or connect 'it to the vdivided'line battery by a suitable return wire. When anyone of the transmitting keys is depressed, one or more of the live impulse selectin or ole changing switches A will be shifte anld one or more of the

live line branches

1, 2, 3, 4 and 5 will be connected thereby to the negative side of the. line battery while the others remain connected to the positive side thereof. At the same time the switch a-will also be shifted by the depression of any key to close the operating circuit from the local battery .20. lCurrent will thenv flow from the local battery by conductor 19, switch ja, conductor 18, un-

locking switch Z and by conductor 16 to the coils of the locking magnet E and of the rst transmitter relay B1. The magnet E will thus be energized tolock the shifted key in depressed position and prevent the operation of the remaining keys. The operation` of'the first transmitter relay B1 shifts its swltchbs to connect the second transmitter relay B2 to the local battery through the con- 125 ductor 16, switch bs and `conductor 15. The second transmitter relay B2 is then energized and in a similar manner operates its switch bs and' connects the third transmitter relay B3 to the local battery. The oper# 180 A ation of this -relay connects the fourth trans-y mitter relay to the'local battery and it will then connect the fifth transmitter relay B5 thereto. The operation of the'relay B5 shifts, its switch bs and connects the magnet B6 to the local battery from the conductor l18 to the switch ba and the conductor 17 leading therefrom' to the coil Aof the magnet B6. The operation ofthis magnet shifts the unlocking switch b? 'and' thereby disconnects the conductor 16 from the'local battery and opens the locall operating circuit through the transmitter relays and through the magnet E, andv the .parts operated are restored to normal condition. y

The transmitter relay magnets and the magnet B5 are thus successively connected to the. lgc albattery and are operated in order,

the circuit therethrouglrbeinggopenedY at the end of the operation by the magnetY BGL" Thisl effects the successive operation of the transmitter switches b1, b2, b5, 'b4 and b5' to transmit the selected permutation or code signal bysuccessively connecting the line' branches l', 2, 3, 4 and 5 to the' line. When the switch!)1 is shifted, current iiows from the divided linebattery 7 by theconductors 6 or 8 (in accordance as to whether or not the rst pole changing switch A has been shifted) to this switch, thence byY conductor 1 to the transmitter switch b1 through the transmitter switches b2, b5, b4 and b5 in order, to the conductor 11, switch D, conductor 13, throughthe coils 14 of the line relay D1 `at the transmitting station, thence \fnthe line lto thelinerelayat the receiving station the latter being, as`stated, con' nectedl by the switelzQat the receiving staf tion to the ground or to a `suitable return wire leading back to the dl'dedine battery 7. The first impulse of the code\signal"\ or permutation is then transmittedv to the line and through the line relays D1 at the transmitting and receiving stations and this first impulse is posit-ive or negative,`in accordance as to whether or not the first selecting switch A has been shifted.

The operation of the'second transmitter relay B2 shifts the transmitter switch b2, i thereby disconnecting the first line branch 1 from the line and connecting the second line branch thereto. The second impulse of the4 permutation', eitherv positive or negative, in accordance with the position of the second selecting switch A, is then transmitted over the line. Similarly, the operation of each of the other transmitter relays B3, B4, and B5 disconnects the preceding line branch and interrupts the sending of the preceding imymlsaconnects the succeeding line branch and effects the transmission of the succeeding impulse until all five impulses of the permutation have been transmitted. The transmission of the fifth impulse is interrupted by the operation of the magnet B6 Ywhich shifts the switch b5 and thereby disconnects the conductor 11 from the set of transmitting switches. This relay also shifts `by the switch b?, since, when the atter is shifted, current Hows from thepower wire 18 through the switch b5 and thence by the conductor 17, through the coil of the relay B5. The circuit of the magnet B6 thus remains in closed condition untilthe selected key is released to restore the switch a to its normal open condition and thereby disconneet theconductor 18 from the local battery 20. The-relay BG the'n remains energized as long asl the selected key is held depressed and the transmitting relays and the magnet E are cut off from the local power circuitand also. from the line and, although the operator may depress other keysof the machine, no effect will be produced thereby until he releases the depressed. key to 'open the circuit through the relay B6.

By this arrangement, it is impossible to overlapA the signalsin transmission. When any'key isdepressed, it initiates the operation of the transmittin relays,is locked in depressed condition an the remaining keys is restored to normal position and the operator may then depress another key. He cannot, however, transmit the'succeeding signal until he releases the key first depressed, since, as stated. it is necessary to do this to open the circuit of 'the magnet B6. The switch bs of the last transmitter relay B5 is connected to the' conductor 18 and not to the conductor---1, as are the switches bs of the sol othertransmittercrrelays. The switchb", of

the unlocking magnetior relay7 B6 discon- VFnects conductor 16 from"ithe-cconductor 18 that leads from the battery and, ifmthe switch b5 were connected to the conductorV 16, lthe magnet B5 would open and'close its own circuit and a buzzer-like action would be roduced.

' he line conductor 13, asabove stated, passes through the coils 14 of the line relays D1, both at the transmitting and the.

receiving stations. The line' relay controls 'which is thus connected to one side of the local battery 20 through the unlocking switch F. The circuit through the local coils 22 of the line relay are always closedduring v' the operation of the apparatus. The armal ture d is normally held in central position .Wlmthis'operating circuit conductor to one or between a pair of contacts12eL and the coils 22 balance one another and take the place of the permanent magnet ordinarily employed in a polarized relay. An. impulse passing Aover the line circuit and through the coils 14 will neutralize one of the coils 22 and will strengthen the other so that the'l armature d will be shifted into engagement with one or the other of a pair of contacts 24v in accordance with the polarity of the line impulse.

The conductor 23, whichis connected Gis arranged to opera-te a pair of locking switchesv g1I and g3 that arel connected to the local battery 20 through the normally closed unlocking switch F and the conductor 19,l like the battery wire 19, is shown in heavylines in the diagram and is provided relays G1 will cut out the other selecting re- .lay G1 of the irstpair so that it cannot be operated. 'In a similar manner, the coils of the second pair of selecting relays 'G2 are connected to the back contacts -of the trans- .fen switches h2 byia pair of branch conduc- .tors 32 and 32'I and the third and fourth fourth' 'pair of transferswitches h4.

Each of the selecting relays G1, G?, G3y and branches of the battery wire 23 that, as stated, lead from the battery 20 through the 'with a -number of 'branches leading to dif- `fconductor 19 and the normally closed lock-v ferent portions of the sglecti-ng'paratus.

The armature;etfofwtle line relay connects the other of ra' pair of conductors 2,5. The

. flow of current through the conductors 25 is arranged to selectively control a number of pairs of relays G1, G2, G3, G4 and A series'oftransfer switches h1, h2, h3 and h1 are arranged'in ,pairs and areI adapted to be operated by a set of relays H1, H1, l-l3 and H* to successivel connect the circuits of the selecting relays 1, G2, G3, G1 and G to the pair. of conductors 25 as. the impulses of a given permutation are received.k The'- switches h1 of the first transfer' relay H1are y connectedto the pair of main conductors @in the branch conductors 31 is operated The switches hzeof the second transfer relay H2 are connected by a pair of conductors 26 to the front or normally disengaged contacts of the switches h1 of the first transfer relay. In-,a similar way, the Switches of the third and fourth transfer relays are connected toV the front or normally disengaged contacts` erated by one of the pair of selecting relays G1 and the branch, conductor leads to the other relay G1 and theswitch g1 interposed the second relay "G1 of the pair and .leads to the'coil of the first relay of thel pair. The operation .of either of the pair of selecting The switch g1 in the branch conductor 31 is opindgmswitch F. f The contacts of the switches 'contacts of switches g3 of each pair of selectf ing relays are connected by conductors 36`to the coil of the corresponding transfer switch. relay H1, so that when either of thep'airs of's'electing relays G1 is operated, the corresponding transferrswitch'h1 will also be operated andthe 'circuit of the local battery .through itscoil will be held to closed condition so long as either one of the relays G1 remains energized. In a similarv manner, the operation of either'one of the pair of selecting magnets G2 will energize the second transfer-switch relayH2 and the operation n of either of the pair of magnets G8 or `G1 will operate the corresponding transfer switch relays H1'. and H4.

As` stated, each signal or character -is impulse will energize the line relay D1 and shift the armature in one' or the' other direction, so that the circuit from the vlocal.

-battery 20 may be traced therefrom by thev conductor 19, normally closed unlocking switch F', Ibattery wire 23 to the line relay represented 'by a permutation of five im? f. `pulses of opposite polarity. The first line armatured and thence by oneror 4the other of the main conductors 25 to one or the other of the switches h1 of the rst transfer switch relay H1 and thence by one or the other of the branch conductors 31 or 31l through the switches g1 therein to the coil of oneor the other or the first pair 4of selecting relays 'G' and then back to the local battery 2.)'

by a suitable returny wire to the local bat-A tery 2O.4 If the first vline impulse is positive,

Vthe selecting relay G1 interposed inthe l() branch conductor 31 will be energized and if negative, the selecting relay Gr1 in the branch conductor 31 will be energized and this branch conductor will be locked in closed condition at this point. .That is to say,'the operation of either of the pair of selecting relays G1 will shift the corresponding set of switches g1, g2 and g3. The operation of the switch g1 will cut out the other selecting relay of the pair and the operation of the switch g2 will close the locking circuit from one of the branches of the battery wire 23 through the coil of the selectedone of the rst pair' of relays and it will be held closed independently of the further operation of the line'relay D2. The operation of the switch g3 of either of the first pair of selecting relays G1, will close the local bat-.

tery circuit through the first transferswitch relay H1 by connecting the battery wire 234 to the coil of the relay H1 through the conductor 36. The first transferswitch relay thereto th ough the medium ofthe second pair of transfer switches h2 and the conduc-- tors 26 that are connected to the normally disengaged. or front contacts of the switches of the main conductors`25 to one of theI switches h1 of the first Itransfer relay Ht,

thence by one of the conductors 26 to one ofi vthe pair of switches h2v of the second transfer relay and thence either by one of the branch conductors 32 or the branch conductor 32 to one or the other of the second pair of selecting and locking relays G2. The second line impulse of the permutation will thus select one orl the other of the

branch conductors

32 or 32 and will lock the local operating circuit through one or the other of the second pair of the selecting relays G2. lThe v operation of either of thesepairof relays will disconnect the second pair of

branch conductors

32 and 32 from the main conductors 25 and will connect the third pair of

branch conductors

33 and 33 thereto, so that the third impulse of the set will operate either one of the two magnets G3 and lock the circuit of theselected magnet -in closed 'condition 'and the fourth impulseof the permutation will select one or the other of the pair of relays G4 and lock its circuit in closed condition. The fifth impulse of the permutation will select one or the other lof the branch conductors 35 or 35 and operate one of the pair lof magnets G" interposed therein.

In the system set forth in the Patent No. 1,199,011, above referred to, there were ten relays in the transmitting set, the first being arranged to connect the lirst line branch to the line, the second to disconnect it therefrom, the third lconnecting the second line branch to the line, the fourth disconnecting the second branch, and so 011, so that the permutations of any given signal were transmitted with appreciable pauses `0r interruptions of the main line circuit. Inthat system, the transfer switches at theyreceiver which successively connected the pairs of lbranch circuits -and ofrlocking and selectin-g relays therein to the main conductors controlled by the line battery, operated at the pauses or interruptions of the 'main line circuit between the-separate impulses ofthe permutation. 'The second transmitting relay B2 in the system here shown, not only disconnects the first line battery l, but connects the second line battery 2 thereto and the third relay B3 disconnects the second line branch 2 and connects the Ithird line branch 3 thereto and so on, so that the impulses of any given permutation follow one another with great rapidity and with practically no','or only very slight, interruptions in the line circuit. At least, the effect of the .inductive capacity of the line and the'magnetic lag ofthe line relays is such that the i slight interruptions in the line circuit. be-

tween the successive impulses does not affect the line relay and its armature is not moved vwhen the transmission of any, given permuvlength and three impulsesa long impulse of three times the length of an lordinary impulse. It follows that the selecting relays l must be variably, responsivey to differentlengths of impulses and be independent of any .interruptions in the line' circuit between the impulses of likeV polarity in any given signal.

The transfer switch relays in the present system, instead of acting at the pauses be tween the impulses of the? permutation as in the prior system referred to, operate as above described, as soon as eitherone of the corresponding pair of selecting magnets is .energized and the s eed of operation-of the selecting andtrans er switch relaymagnet is. tuned to correspond with the speed of operation of the transmitting relays.

The first impulse of a permutation 1s sent.

to theline as soon as the first transmitting relay vB1 is energized. At the vsame time, the circuit of the second transmitting relay B2 is connected to the local battery and the length of the first impulse depends upon thetime required .forthe -second 4relay B2 to operate.' InA the same way, the length of the succeeding impulses .in the permutations' depend up'on the length of time it :requires the succeeding transmitting relays to operate.4

These transmitting relays are relatively slow actingso that heavy, strong im ulses may be impressed upon the line circuit. The selecting relays G1, G2, G3, G1 and G5 ofthe receiver are preferably verysensitive, quickactin magnets so that they will quickly respon to the operationvof the line rela D1, while the transfer switch relays- H1, H52 H3 and H1 which are operated from they-local battery through the medium ofthe selecting relays, may be relativelyAslow-acting. The

. vtiming'. ofthe transfer switch and selecting f relays is such that,- the time required for one .of the' first pair of selecting relays G1 ,and

the first transmitting switch relay H1 to operate is the same as required by the second transmit-ting relay B2 to operate. The tlme required to operate'one of the second pair of selecting relays G2 and the second switch relay'H2 is the same 'as is required by the transmitting relay B3. .In asimilar manner,

'the time of operation ofon of the third set of selecting relays G2 andthe transmitting switch relay H3 andof one of the selecting relays G4 and thetransfer switch relay H* correspond 'respectively to the time of opera- 'tion ofthe transmitting 4relays B4 and' B52. 'By reason of this arrangement, it is not necessary to interrupt the line circuit between'the impulses of like polarityv in any given. permutation. firsttwoimpulses of any permutation are of- For example, if the the same polarity to givevin effect` one impulsev of double length, it will'irst, as' described, operate one ofthe pair of selecting relays G1 andthe transfer relay H1 and then properly loperate 'one of the selecting relays G2 and the transfer switch-relay H2. If this vdouble impulse is positive, the branch conductors 31 and 32 will be selected and if negativa-the branch conductors 31 -and. 32-

will 'be selected. If the first three impulses of the permutation are of the same polarity thereby forming in effectl at the receiver one long impulse of three times the length of an ordinary impulse, and the third pair of selecting relays G3 will be operated and the third transfer relayH3 and one or the other of the branch conductors 33 or 33 'will be selected.

Impulses of .like polarity in any givenpermutation orv signal canthusfollow one another without any appreciable interruption of the line circuit.- At least, there need not be sufficient interruptionl inthe line circuit to causethe armature of the line relay to drop-back from one of the contacts 24, since spond'to' the different lengths of impulses formed by crowding together succeeding impulses of like polarity in any permutation. After the transmission of the permutation -is once'initiated, the only changes occurring l in the line circuit are reversals of polarity. The transmission ofthe succeeding impulses of any permutation may therefore be effectthe set'of selecting relays will variab-ly reed rapidly. Moreover, the proper selective operation of the system is not inter-.-

fered with by the inductive capacity ofthe lineor the magnetic lag of .the line relays, since itis not necessary that there should be distinct pausesbetween the impulses and sincel reversals on the line will quickly overcome the lag due to eitherof these causes. -Moreover the system is not liableto be affected by different lweather conditions or by other disturbing influences.

It is not necessary that the synchronous operation or tuning of the transmitting and receiving relays be absolutely accurate. Fig. 3 indicates diagrammatical y the operation of the diffe-rent relays fwhen a permutation comprising two positive impulses, two negative impulses and a fifth positive 4impulse is transmitted. The first impulse begins at the operation ofthe first transmitting'relayB.1 and its llength is determined bythe period of operation of the second transmitting relay B2. In a similar manner lthelengths ofthe succeeding impulses are determined by the period of operation of Y the magnets B3, B4, B5'l and BG. There is .little orno appreciable pause between the impulses and in ordinary operation there is which the corresponding impulses are passing over the line circuit. When an impulse of Y ,negative polarity follows an impulse of positive polarity or lyice versa in a. permutation or signal, it is not necessary that the reversal ofthe line circuit shall occur in absolute synchronism of the operation of the corresponding transfer relay since, whenone of the pair of selecting relays is operated it cuts out the other relay of the same pairby means of its switch g1. For example, if the second impulse of a permutation is positive e and the third. negative, the positive impulse relay G2 in the branch conductor 32 which responds to negative impulses, then, if the line reversal occurs before the transfer switch i H2 has completed its operation, it

lecting relay G2 and it is only necessary that this second impulse shall be prolonged sufficiently to select the negatively responsive relay G3 of the third pair and thereby connect the branch conductor 33 to the local battery.

This arrangement not only permits the impulses of any given. permutation to follow one another very rapidly and thereby' increase the speed of transmission of messages, but also avoids the diliculty heretofore encountered in electric selective systems, due to the lag of the line 'circuit which varies with the length and `'capacity of the line, with the weat-her conditions and with the adjusting of the line relays. As explained above, the synchrony in theoperation of the transmitter and receiver need not be absolutely perfect. Moreover, inasmuch as the transmitting and selecting relays are restored to normal position at the end of any complete permutation or code signal, the transmitter and yreceiver start in perfect synchrony at the beginning of each signal.

The variable operation of the magnets G1. G2, G3, G4 and G5 may be employed to make the :signal in any suitable manner.

-For example, they could be employed to operate a series of switches of a fan circuit in manner set forth in the Patent No. 1,199,011, above referred to, or could be employed to 'control the operation of a set of mechanical selecting devices, as set forth in the other patent referred to No. 1,232,045.

At the complete operation of any signal the normally closed unlocking switch F is opened, to restore the selecting 'circuits of the receiverto normal condition in readiness to receive the next permutation or signal. This switch may be opened in any suitable manner. In the arrangement shown, it is controlled by'a magnet F1, the circuit of which is arrangedrto be closed from a battery wire 19 through a pair of normally open switches g4, and a conductor 37 leading to the coil of the magnet F1. The switches g4 are operated by the last pair of selecting magnets or relays G5, sp that when either of these magnets is operated, the circuit of the unlocking magnet F1 will be completed and vthe switch F operated to disconnect all portionsof the receiver from the local battery and thereby Ypermit the restoration of all parts to normal condition.

In the arrangement shown in Fig. 1, the line circuit is normally open. The arrangement shown in Fig. 2' is designed more particularly for` duplex operation and the line will operate the selecting relay 'G2 in thel branch conductor 32 and will cut out the circuit is'normally closed. The arrangement of the transmitter Iis similar to that shown in Fig. 1, except that an additional starting relay B is added to the set of transmitting relays. 'This relay controls the switch b9 which Connects the battery wire 19 to the cannot affect the negatively responsive, se-

conductor 18. It also controls a switch b which is connected by a conductor 37 to `a normally engaged or back contact of the transmitter switch b1 which'is yoperated by the relay'Bl. The front and back contacts of the switch b are Connected by extensions 6 and 8' of the conductors@ and 8 to the opposite sides of the divided line battery 7, the arrangement being such that the negative side of the divided battery is normally connected to the line through the conductor 6', switch b, conductor 37, the set of transmitter switches b1, b2, bs, b* and b5,connected bythe wires 9, the conductor 10, switch b and' conductor 11. The conductor 1 1 is connected by branch conductors 38 to' the separate coils of a diii'erential polarized r'e-4 lay K and thence through one`coil to va line conductor 39, and through the opposite coil to an artificial line comprising an adjustable resistance 40 and a condenser 41. The adjustable resistance and condenser forming the articial line are, as usual, grounded.

The starting relay B also controls a switch bs, which connects the conductor 16 to the coil of the succeeding relay B1 by a conductor 15. The-set of transmitting relays, like that shown 'in Fig. 1, operate inV order to su'ccessively connect the line branches A1, 2, 3, et andl 5 to thelline. As the' line is normally closed, a starting or controlling impulse must be transmitted over thel line to initiate,

the operation of the selecting receiver; This is eect'ed by' the relay B which disconnects the conductor 6 from the line and connects the conductor'S thereto, so that the rst im- `pulse of any signal is always .positive and cannot be varied to aid'in' the selection of the diierent characters. Each slgnal must therefore bemade upof six impulses, the first of whichy 1s merely a starting impulse and thev trols a home recorder at the transmitting a station and the 4relay will of course respond to such transmitted impulses, but the duplex relay K will only respond to'im- 'pulses received from a distant station. Preferably the conductor 1l extends through two polarized relays in succession, .one of which controls the home recorder and the other of which controls la circuit extending through the coils of the differential relay tothe line conductor and to the grounded artificial line. Y The recorders for'transmitted and received signals -controlled.respectively by the relays K1 and K are alike. The armatures k of ofthese relays are Vconnected to the battery wire'l9 through normally closed unlocking switches L anda branched conductor 43. The two contacts44 and 45 of each armature are respectively" connected by two conl5 ductors 46 and 47 to twoswitches m2 and 'm4 which are arranged to be operated'by a ma'gnet M4. The normally closed orback contacts of these switches are connected to a pair of

conductors

48 and 49 which lead, respectively, to the switches m and n of a pair of starting relays M and N. The conductor 49 also extends to the coil of the magnet N. The relays M, N and M4 form part of\a set or series of magnets, the other magnetsI or relays ofthe series beingdesignated by the letters M1, M2, M3 and N1, N2, N3 and N4.

These magnetsfare' all alternately arrangedin a series, as shown, and each magnet of the series is arranged tor close the circuit of the succeeding magnet in the set, so that when the operation of the set is once initiated, they will operate in order.

Thel normally disengaged contact of the switch is connected to the battery through the normally closed unlocking switch Lby means ofthe branch conductor 43. As the line is no1'- mally closed, the armature lo of the line relay normally engages the' contact 44. The rst impulse of all signals is lof the same polarity-positive in the arrangement set forth-and serves to shift the armature into engagement with the contact 45. This closes the Circuit of the local battery through the conductor 19, unlocking switch L, conductor l43, armature 7c, Contact 45, Y conductor 47, switch m4, conductor 49, through the starting relay N. It will be understood that all the relays are connected either to ground or by a suitable` return wire to the local battery. The switch n of the starting relay N then locks the circuit, through the coil of the relay N, in closed condition by'connecting the battery wire 43 thereto. It also locks vthe conductor 49 into'connection with the conductor 43. The conductor 49 is connected to a series of switches a5 which are arranged to be operated one by each'of the set of relays` N, M,N, M', etc. The normally disengaged i Contact of the switch 71,5 of each relayis connected to the coil of the next relay of the set by a conductor 50. Thus, when the start- 4 ing relay N is operated, the succeeding re- -lays will be successively connected to the battery thro'ughthe conductor 19, unlocking switch L, conductor 43, switch n, conductor 49 and the switches a5 which operate in order to connect the set of relays successively to the local battery through the medium of the conductors 50.

In addition to the successively operating relays,.e'ach receiver has a set of selecting magnets or relays P1, P2, P3, P4, P5 and P6. These magnets are all connected on one side to thelocal battery through the ground or ay suitable return wire. On the opposite side magnets P1, P2, P4 and P4 are connected, respectively, by a set of .conductors 51, 52, 53 and 54 to a'series of normally closed switches nl, n2, n3 and n4 which are operated respectively by the relays N1, N2, N2 and N4. The selecting relays P5 and P6 are connected by a pair of conductors 55 and 56 to the normally dis-engaged contacts of the switches m3 and m4. The normally engaging contacts 'of the closed switches nl, n2, n3

and'n4 are` connected by conductors 57 to the contactsof a set of normally open switches mand m. These switches are connected to branches of the-conductor 48 and are arranged to be operated in order by the inagnets M, M1, M2 and MA3 when the set of receiving .relays are operated in order. In this way local branch conductors which include the select-ing magnets orrelays P1, P2, P-`3 and P4 are successively connected one at a time, as any signal is received, by the switches m, m1, 711,07?, n3 and n4 to the conductor 48. This conductor, however, is only connected to the local battery through the contact 44 by means of the switch m3, conductor 4G, Contact 44, relay arn'xature L", conductor 43 and locking switch L and conductor 19. The armature c only engages the contact 44 when thenegative impulse is received. The set of relays N, M, etc., operate in order. whenever any signal i's received. Theyare also timed to operate in substantial synchronism with the speed o ftransmission or lengths of the impulses of any signal. In this way, the circuit of the selecting relay P1 will be'connected to the contact 44 of the line relay when the first impulse is received, and will be operated if the first impulse is negative, but will remain unaffected if the first impulse is positive. In a similar manner the selectin relays P2 P3 and P4 are successively connected to the contact 44 of the line relay as the second, third and fourth impulses are received and will be variably operatedI in accordance with the polarity of such impulses. When the last impulse of any permutation is received, the relay M4 is operated and connects the circuit of the two selecting relays P5 and P6 'to the contacts 44 and 45 ofthe line relay through the pairs ofconductors 46,; 47 and 55, 56, and switches m2 and m4 sothat one or the other of these magnets will beroperated in accordance with the polarity of the last impulse of the signal.

- iso rlhe operation of any of the selecting magnets P1, P2, P3 and 1:1 will lock the local battery in closed condition through its own coil by means of a normally open locking switch P7, which serves to connectthe local battery to the coil of the corresponding selecting magnet' from the wire 19, unlocking switch L and branch conductor 43. Thus, when any one of the selecting relays is operated, its circuit will remain in closed condition until the unlocking switch L is opened. The variable operation of the setA of selecting magnets can be arranged to make or record a signal in any suitable manner, for example, as set forth in the patentsreferred to. At the completion of any signal, the

operation of one or the other of the selecting magnets P5' or P6 will operate one of a pair of switches P8 and thereby close the circuit through a coil of the magnet L1 from the battery wire 19, switch Ps and conductor 5S. The magnet L1 serves to open the unlocking switch L and restore the recording relays to normal condition.

Here, as in the arrangement shown in Fig. 1, it is not'necessary that the transmitter and receiver operate in exact synchronism. To assist in the tuning or timing of the two sets of transmitting and receiving relays,

they are preferably connected to the local battery throughv return conductors 59 and 60, having adjustable resistances 61 interposed therein, so'that the speed of operation of the two Sets may be controlled, as desired.

The successively acting receiving magi nets, shown in Fig. 2, could of course be arranged to operate upon the open circuit with five impulses in each permutation, as inthe arrangement or system-shown in Fig. 1. In'

such case, however, the magnets B, M and N could be omitted, but the system could not be readily operated for the duplex transmission of messages. Similarly, by adding the starting magnets or relays to the ar-` rangement shown in Fig. 1, similar to the magnets B, M' and N, that arrangement could be employed with a -normally closed circuit and a differential line relay or the duplex transmission of signals. Y

lt is obvious that numerous changes can be made in the details and arrangements of circuits set forth without. departure from the broad scope of the invention, as defined in the claims.

I claim as my invention: y

1. ln printing telegraphy, the method of selective signaling which consists in operating a transmitter solely under local control to impart to a line character signals of uniform length and each comprising the same number of positive or negatveimpulses in quickl succession and without perceptible spacing intervals between the impulses, initiating the operation' 0i .a selecting receiver impulses at the beginning of each signal,

timing the operation o the switch mechanism in synchronism with the transmitted impulses of each signal independently of the line circuit land restoring the same to a condition of rest at the completion of each signal.

2. In printing telegraphy, the method of selective signaling which consists in operating a transmitter solely under local control to impart to a line character signals of uniform length'. and each comprising a dilierent permutation of a definite number of irnpulses of opposite polarity, locally timing the operation of a receiver switch mechanism to associate the selecting devices of the receiver successively with the line in synchronism with the transmitted impulses of the character signals to thereby variably operate the same in different combinations,A and, at the end of each signal, arresting the operation of said switch mechanism and again starting the same in response to the ing to theline character signals each com-` prising .a ditl'erentl permutation of v-e impulses of opposite polarity preceded by a l line'current reversal or starting pulse, controlling at each character selection, the initial operation of a selecting receiver in response to said transmitted starting impulses, and thereafter, under local control and at spaced intervals corresponding with the midportions of the permutation impulses, successively bringing the selecting devices of the. receiver into operative relation with the line to thereby effect the character selections.

4. In printing telegraphy, the method of selective signaling which consists in normally maintaining current on a line, operating a transmitter solely. under local control to impart to the line character signals of uniform length andl each comprising a different lpermutation of two different line conditions extending through a definite number of time intervals,` initiating the operation of a selecting receiver in response tothe first change inline condition of each signal and thereafter, under local control and at spaced intervals corresponding with the mid-portions of said time intervals, successively bringing the selective devices of the receiver successively into operative relation with the line to variably operate the same in accordance with the two dil'lerent line conditions.

5. In printing telegraphy, the method of controlling a selecting receiver which consists in operating a transmitter solely under lio signals of -uniform length and' each comprising la different permutation of positive and negative impulses in quick succession and,

without'pereeptible spacingintervals, iniing the operation of said switch mechanismv tiating theoperation of the receiver switclr mechanism at '-the beginning of character signals and in responseto impulses imparted to the line by lsaid transmitter, locally timto associate .the receiver selecting devices with the line successively and at spaced in-v tervals corresponding with portions onlyv or` the transmitted impulses and, at regular intervals between character signals, arresting the operation of said switch mechanism.

6. In telegraphy, the method of selective,

signaling which'consists-in transmitting permutations of a definite number of-impulses of opposite polarity and of uniform length over a normally closed line circuit, initiating the operation of a series of selecting devices at' the receiver by the first impulse of each permutation or signal, electro-magnetically maintaining 'the Operation' of said selecting devices in synchronismv independently ofthe transmittedimpulses, and `restoring the selecting devices to normal at the completion of each signal. A

7; In selective systems for printing tele' graphs, the combination with a normally closedline, a transmitter having a normal condition of rest, and operative under local control fon-imparting to the line character signals of equal length, means for initiating the operation of said transmitter, the

latter having means independent. of said 'starting means for restoring the line to normal atV the endl of each signal, a receiver having a set of'selecting magnets, transfer switch mechanism for associating said selective magnets with the line in predetermined order, means responsive to the rst l .impulse of-each signal for initiating the opto a condition of rest eration of said switchjmechanism, and locally timed means `for controlling such operation in synchronism with said transmitter and for restoring said switch mechanism Aat the end of each signal.

8. A selective system for printing telegraphs' comprising a line, transmitter switch mechanism operating solely under local control to impart to the line character signals of equal length and each comprising the same number of positive or negative impulses in quick succession and without spaceration, for maintaining said switch mechanism in synchronism with the transmitted graphs andthe like in which the signals are represented by permutations of a definite number of impulses of opposite polarity, the

impulses of the character signals, means for arresting the operation 'of said switch mechanism at regular intervals and at the. end of: character signals, and means responsive toV impulses imparted to the line by said transmitter for again initiating the` operation of said switch mechanism.

9. A selective printing telegraph system comprising a line, transmitter switch mechanism for imparting thereto character signals of equal length and each comprising a different lpermutation of impulses of opposite polarity, -a'receiver having a set of selecting devices, transfer switch mechanism initiated in operation by the first transmit- 80 ted impulse of each signal but otherwise locally controlled, for successively associatingsaid selecting` devices with the line to therebyvariably operate the same in different combinations and-in accordance with the polarity of the transmitted impulses,

-means for maintaining said selecting devices in operated condition, and means for restoring the same to normal at the end of each signal. c 90 10. In selectivesystems for printingv telegraphs and the like, in which vthe signals are represented by permutations of a definite number of impulses of opposite polarity, the combination With a normally closed line.cir cuit, of 'la transmitter for imparting the permutations of impulses or signals ea'ch preceded by a starting impulse to the line, .and a selectingreceiver having means controlled by the transmission-'of each startingl impulse for initiating the operation thereof, electromagnetic -devices or .effecting the successive operations of the receiver in synchronism with the transmitted impulses but independently ofthe line circuit, and means for arresting 'the operation of Ithe ,receiver at the completion of each'permutation or signal. I.

11. In selective systems for printing tele- `COIIlbinfltiOll of a transmitter for impartmg the permutations of impulses or signals to the lineJ at a delinite rate, a selecting receiver comprisinga set of magnets arranged to operate in order and having periods of operation corresponding to the lengths of the impulses of each signal, whereby successive impulses of like polarity in anyl signal can follow one another on the line circuit without intermedilate breaks.

'without perceptible breaks or pauses be- 130 tween impulses, a synchronously operatinglreceiver arranged' to respondV variably both to the impulses of'opposite polarity and to impulses 'of like polarity but 'ofk different lengths and elect'ro-magnetic''meansfresponL sive to the first impulsesof the signals for controllingthe initial operation of said rereceiverat each character Selection.

13. In selective systems for printing telegraphs and the like in which the signals are represented by permutations of a definite number 'of impulses of opposite polarity, the combination of a transmitter for imparting the permutations of impulses or signals to the line at a definitefrate, a series of selecting relays, and a series of intermediate spacing or' transfer relays, said selecting and intermediate relays being arranged to operate in order and in synchronismwith'said transmitter independently of spacing intervals between the impulses.

14. In selective systems for printing telegraphs and the like inywhich the signals are represented by permutations of a definite.

number of impulses of opposite polarity, the combination of a transmitter for imparting the permutations of'impulses or signals to the line at a definite rate, a series of selecting relays arranged in pairs, an operating circuit for said relays, and means controlled by the operation of either relay of a pair for immediately connecting the' succeeding pair of relays to said operating circuit.

15. In selective `systems for printing telegraphs and tlne like in which the signals are represented by permutations of a definite 'number of impulses of opposite polarity, the

combination of a transmitter for imparting the permutations of impulses or signals to the line at a definite rate, a series of selecting relays arranged in pairs, an operating circuit for said relays, a line relay controlling said operating circuit, a set of transfer switch relays. means controlled by the operation of either selecting relay of a pair for immediately energizing the corresponding transfer switch relayto'connect the succeeding pair of selecting relays to said operating circuit, said relays being timed to operate in synchronism with said transmitter.

16. ln selective systems for printing telei graphs and the like in which the signals are represented byv permutations of a definite number of impulses of opposite polarity,l

the combination of a transmitter for imparting the permutations of impulses or signals to the line at a definite rate, a receiver comprising a set of selecting magnets arranged lto be variably energized by the impulses of each permutation or signal, a line relay controlling the circuits of said selecting magnets, and electromagnetic means initiated in operation at intervals by transmitted impulses but otherwise locally timed to op- -magnets to said line relay.

magnets to said line relay. l A

1:7."lfn selective system for printing telegraphs and the like in ivhich the signals a're represented by permutations of ade'finite number of impulses of' opposite polaritynthe combination of a transmitter for imparting the permutations of impulses or signals 'to the line at a definite rate, azreceiver comprising a set' of rselet'eting magnets arranged to be variably energized by the impulses of each permutation or'signal, a line relay con'- trolling .the circuit of said selecting magnets and a set of'relays, the circuit of each of which is controlled a preceding magnet 'of the set, means controlled by the first im'- pulse of any signal for initiating the opera# tion of said set lof relays,v said relays being tuned tov operate in synchronism With said transmitter, vand means controlled thereby for' successively connecting 'saidy selecting y t Jfor printingitelegraphs in which the signals are represented Y 18. In selective systems by different permutations of a definite number of impulses ofopposite polarity, the

combination of atransm'itter for imparting the permutations of impulsesor signals to the line at a deniterate, means for selecting the signal impulses andv for initiating the operation of said transmitter, said transmitter having means independent of said impulse' selecting and starting means for restoring the line to normal at the end of each signal, locking ,means for compelling 'the completel operation of said transmltter after its operation is once initiated, ai receiver adapted to operate under local control 1n chronism with said transmitter, means as y controlled by the first impulse of any permu- Vtation or signal for initiating the operation f said receiver, and means for restoring the latter to a condition of rest at the completion ,of each signal.

' 19. In electric selective systems in lwhich the signals 'are represented by permutations of a definite number of impulses of opposite polarity, the combination of a normally closed line circuit, a transmitter at each station for imparting the permutationsof code impulses and additional starting impulses to the line circuit, a duplex relay at each station, and a selecting receiver controlled by each duplex relay in response to the permutation and starting impulses received from a distant'station;'

signal to the line, a duplex relay at each station,y and a set of synchronousy acting selecting relays controlled by sai duplex relay and responsive to signals from a distant station.

21. In selective systems for printing telegraphs and the like in which the signals are represented by permutations of a deinite number of impulses of opposite polarity, the combination of a transmitter for 1mparting permutations or signals to the line spectively of each signal, and means for adjusting the time of operation of said transmitter and receiver to 'effect the proper synchronous operation.

22. In selective systems for printing telegraphs and the like in which the signals are represented by permutations of a definite number of impulses of opposite polarity, the

combination of a transmitter comprising a set of relays arranged to automatically operate in order, a receiver comprising a set of relaysarranged to automatically operate in order and in synchronism with the operation of said transmitter relays and means for varying the speed of operation or for tuning thesaid `sets of transmitting and receiving relays to eil'ect proper synchronism.

23; A selective system for printing telegraphs comprising a line, a transmitter operating solely under local control to impart to the line character signals, each comprising a diii'erent permutation of two different line conditions extending through a definite number of time intervals without perceptible spaces between the intervals, a receiver having a set of selecting magnets, transfer switch mechanism locally. timed in operation during each `character selectionV for bringing said selecting magnets into operative relation with the line successively and at spacedintervals corresponding with the mid-portions of said time intervals, means forv arresting the operation of said switch mechanism at the end of each character si al, and means responsive ,to first change 1n line condition of each signal for initiating the operation of said switch mechanism. Y

24. A selectivesystem for printing telegraphs, a normally closed line, a transmitter for imparting to the line starting impulses and character signals comprising different permutations of a definite number of successive positive and negative impulses without perceptible spacing intervals between the impulses, a line relay, a receiver having a set of selecting magnets, transfer switch mechanism, locally timed in operamechanism to a condition ofrest at regular v intervals and at the end of'character signals, and means responsive to said'starting impulses or again initiating the operation thereof.

25. A selective system for printing telegraphs comprising a line, transmitter means adapted 'to maintain current on sa1d line between character signals and operating solely under local control to impart to the line startin line conditions and character signals o equal length and comprising permutations of two diiferent line conditions without perceptible spacing intervals between the impulses, a line relay, a receivery having a setvoi` selecting devices arranged to be set in dierent combinations, and means initiated in .operation at the beginning of each signal by said starting line conditions but otherwise locally timed in operation, for bringing said selecting devices successively into operative relation with said line relay at spaced intervals corresponding with the mid-portions of the signal impulses, and means for arresting the operation of said locally-timed means at the completion of each signal.

26. In a selecting system for printing telegraphs, the combmation with a. normally closed line, of atransmitter having a normal condition of rest and being operative to impart starting` impulses and character signals tothe line, a starting switch for initiating the operation .of said transmitter, the latter having means independent of said starting switch for restoring the line to normal condition at theend of each signal,'a receiver having a set of selecting devices adapted to operate in different combinations to effect the character selections` transfer switch mechanism, locally timed in operation, vfor bringing said selecting devices successively into operative relation with the line, means responsive to said starting impulses for initiating the operation of said switch mecha` nism at the beginning of each signal, and means for restoring the same to a conditlon of'rest at the end `of each signal.

27. In selective' systems for printing telegraphs, the combination of a transmitter for imparting to the line character signals, each comprising a different permutation of two different-'line conditions extending over a definite number of time intervals, a receiver having a set of selective devices adapted to be operated in different combinations to effect the character selections, and electromagnetic means, responsive to first change in line condition of each signal but otherwise locally timed in operation, for

bringing said selective devices successively into operative relation -with the line.

28. In selecting` systems for printing telegraphs, a receiver having a set of selecting devices variably operated in di'erent combinations," a set of relays locally timed in operation, for bringing said selective devices successively into operative relation with the line, line controlled means'for initiating the operation of said set of relays at the beginnings of definite cycles of operation, and means for arresting the operation of said set of relays yat the ends of such cycles.

29. In selecting systems for printing telegraphs, a line, a receiver having a set of` selecting devices arranged to operate in different combinations to effect the character selections, and a set of relays arranged to operate in invariable predetermined order to successively bring said selecting devices into operative relation with said line during each character selection.

30. In selecting systems for printing telegraphs, a line relay, a set of selecting magnets operating in different combinations to effect the character selections, and a set of transfer relays, said magnets and relays being arranged in separate local circuits and thelatter being arranged to operate in predetermined order to bring said selecting magnets successively into operative relation with said line relay.

31. In selecting systems for printing telel graphs, the combination with ya line, of a transmitter for imparting to the line character signals lorf equal length and comprising different permutations of two dierent line conditions, a receiver having a set of selecting magnets adapted to operate in different combinations to eiiect the character selections, transfer switch mechanism, ini-` tiated in operation by starting impulses transmitted over said line but otherwise locally timed in synchronism with said transi current independent of the line circuit for initiating the operation of said transmitter switch mechanism, a starting magnet controlled by impulses accompanying the transmission of character signals over said line for initiating the operation of said receiver switch mechanism at the beginning of each character signaL-a set of impulse selecting switches for determining` the character signals imparted to saidI line by said transmitter, and a corresponding set lof selecting devices successively brought into operative relation with the line by said receiver switch mechanism and thereby variably operated 'in different combinations to eliect the character selections. A 33. In a selective system for printing telegraphs in which the character signals are distinguished by permutations of impulses without spacing intervals between the im'- pulses, the combination with a line, transmitters at each of two connected stations normally maintaining current on the line and adapted to impart the character signals thereto, each preceded by a starting signal, each of said. transmitters' having means locally controlled independently of the line for initiating the operation', and means, independent of said starting means, for 1'estoring the line to normal at the end of each' signal, and selecting receivers at each station normally at rest and locally timed in operation, ysaid receivers each having starting means and sets of selecting devices responsive respectively to the starting and character signals' imparted to the line by the distant transmitter.

34. In a selecting system for printing telegraphs, the combination of a normally I 'ing impulses to the line, each of said receiver switch mechanisms having means for initiating its operation yresponsive to the starting impulses imparted to the line by the distant transmitter switch mechanism, locally controlled means for continuing the operation "of said receiver switch mechanisms and for restoring lthe same to normal conditions of rest', and sets of selecting magnets adapted to be associated in order with the line and variably operated in different combinations by said switch mechanisms to effect the character selections.

35. In selective systems for printing telegraphs in which the character signals are represented by permutations of a definite number of impulses of opposite polarity, the

combination of a duplexed line, independent transmitter and receiver switch mechanisms Aat each end of said line locally timed in lecting magnets adaptedto be'associated in order with the line and operated in different combinations by said switch mechanisms to effect the character selections.

36. Invselecting systems for printing telegraphs, the combination of a normally closed dupleXed line having current nor# mally maintained thereon, independent transmitter and receiver switch mechanisms at opposite ends of said line, locally timed in operation during the character selections,

eachofsaid receiver switch mechanisms havingmeans forarresting its operation at the .end of each character selection, and means for again initiating its operationJ in response to starting impulses imparted to the line by the distant transmitter switch mechanism, and sets of selecting devices adapted to be associated in order with said line and variably operated in dierent combinationsby said switch mechanisms.

37. In selective systemsfor printing telegraphs, a receiver having a set of selecting magnetsadapted to be operated in different combinations to effect the character selecacter selection, for successively bringing said selecting magnets into operative, relation with the line, a starting magnet responsive means for releasing said locking circuit at the end of each signal.

38. In selecting devices for printing telegraphs, the combination :of a transmitter for imparting the character signal to thev line, a receiver having a set of' selecting devices adapted to be operated in ,different combinations to effect the character selections, means responsive to the first impulse of each signal for initiating the operation of said receiver, means for maintaining said starting means in operated condition to continue the operation of said receiver in timed relation with said transmitter independently of the line,and means Vfor restoring said rceiver and said vstarting means to normal at the end of each signal.

HOWARD L. KRUM.

*Witnesses OrriLmC. FREIBERG, KATHARINE GERLACH.