US2174691A

US2174691A - Communication system

Info

Publication number: US2174691A
Application number: US54390A
Authority: US
Inventors: Charles R Doty
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1935-12-14
Filing date: 1935-12-14
Publication date: 1939-10-03
Anticipated expiration: 1956-10-03
Also published as: GB476273A; DE721998C; FR823104A

Description

Oct. 3, r C. R. DOTY COMMUNICATION SYSTEM Filed Dec. 14, 1935 I 3 Sheets-Sheet l FVGBRST' HNJGY'IU g m I,- m

* INVENTOR.

ATTORNEYS.

Oct. 3, 1939; I c, DQTY 2,174,691

COMMUNICATION SYSTEM Filed Dec. 14, 1935 3 Sheets-Sheet 2 ATTORNEYS.

C. R. DOTY COMMUNICATION SYSTEM Filed Dec 14,

1935 3 Shae ts-Sheet 3 INVENTOR M 'ATTORNEY l I I I l I I I I I I I I I I 46 transmission. e

Fig. 4 shows in part one form of registering or atenteei at." is

hit-i stra s estates aster.

This invention relates to communication systems and more particularly to synchronous registering 'controiling systems, one Well known form of which is the printing telegraph system,

5 and is applicable for transmission over both line and radio networks. 5

One object of the present invention is the provisionthat two timed impulsesare employed for all 'the character representations to be transmitted and received and registered accordingly.

Another object of the present invention is that the usual electromagnetic relays connected directly to the line or through a signal amplifier to transmit and respond to the signal impulses are dispensed with and substituted .by substantially 1 inertialess relays having no moving parts.

Another object oi the invention is the provision of means whereby it is impossible to transmit or select subsequent character signal impulses betore the preceding character impulses have been transmitted. v

Still another object is the provision of-means whereby but one character selection can be effected at the receiver at one time. I

Various other objects and advantages of the invention will be obvious from the following particular description of one form of -mechanism embodying the invention or from an inspection of-the accompanying drawings; and the invention also constitutes certain new and useful i'eatures of constructionand combination of parts hereinafter set forth and claimed.

-In the drawings: l

Fig. 1 shows schematically the circuit arrangement of the transmitting circuit.

Fig. 2 shows the ing circuit; Fig...3-shows a modification oi the circuit dia printing. transmitting and ,receiving' unit.

Fig. 5 showsa timing chart as appliedto .the-

system described.

Briefiy and broadly, the present invention comthe said impulses transmitted at certain particuuitidiag'ram the receivigra'rn s when the invention is applied to radio lar timed periods during a predetermined timed interval. Other features and advantages thereof will be obvious as the description progresses.

In accordance with the present invention, in

place of the usual electromagnetic relays con-.

nected directly to the line, electrical discharge tubes are used and are ofa type in which the discharge is started by a momentary application of a signal condition thereto, the discharge continuing independently or the applied signal con dition until interrupted by a locallyccontrolled means.

A convenient form of discharge at. for this apparatus may comprise a gas filled thermionic tube of such construction that when the anode is connected to positive battery and a certain potential is applied to the grid. the tube will start and current will flow from the anode to the cathode. As soon as the plate current Icegins to flow, the grid is instantly surrounded by a sheath of positive ions and has no further effect in controlling the plate circuit; Changing the grid voltage merely changes the thickness of the sheath and has no effect on the potential of I the rest of the space. Hence, removal of the grid potential'will not stop the plate current once it is started. However, it can readily be stopped by removing the plate voltage. The function of the grid may therefore be likened to a trigger. The amount of power required to start the tube is exceedingly small.

A form of thermionic tube having thecharac-f- .cially as thyratron" and consists of an envelope containing a low pressure of vapor'such as mer- -teristics described is the type known .'commercury,.argon, etc. and a plurality of electrodes H grids of the discharge .tubesare maintained at a predetermined negative bias, and adapted so that when the grid bias is sumciently reduced momentarily, the gas becomes ionized andthe anode will draw current until its circuit is be used to limit the amount of grid current of the tubes.

. nature, in response to character signals, it is to be understood, of course, that it is not desired to be limited to the particular means shown.

Before proceeding with the description of the transmitting and receiving circuits, it is advisable to set forth briefly one form of a translating or registering unit which may be embodied in the present invention.

For illustrative purposes, 'this invention is shown as embodying a well known form of translating unit which may be the electromatic typewriter, and hence requires only the following brief description.

Referring to the drawings, and in particular to Fig. 4, in the embodiment illustrated in the drawings, well known means are provided for actuatingthe type bars (not shown) by power operated devices comprising a power driven roller III,

A cam II is pivoted on one arm of a bell crank lever I2 pivoted in the frame, the other arm of which is operatively connected with one arm of a bell crank lever I3 by means of link ll. The other arm of lever I3 is connected to the type bars (not shown) in a well'known manner.

The lever I2 is actuated by the cam I I when the latter engages the driven roller I0 to be operated thereby. The engagement of the cam II with the power roller is controlled by means of the key lever H in a manner which .will now be described;

The cam II is resiliently engaged by a springpressed arm 20 which tends to turn it into engagement with the power driven roller or stop 2| on a lever 22 pivoted on the bell crank I2 and normally arranged in the path of a lug on the cam. When the lever 22 swings to move its stop out of the path of the lug, the arm 20 swings the cam into engagement with the power roller to be actuated thereby to swing the bell crank I2 to actuate its connected mechanism,

The lever 22 has an arm 24 which is provided with an offset projection 25 at itsend which pro-' Jects laterally through an opening in the bell c ank I2 and engages the bifurcated lower end 26 of an arm 21 of akey lever II pivoted onthe common rod 28.

It is obvious then that depression of a key lever I'I releasesthe revolubly mounted cam I I to engage and be actuated by power roller III in turn operating. bell. crank I2, and its attached links to cause the associated mechanism, such as the key bars and other operating mechanisms, to be operated.

Attached to the key lever I1 is a connecting link I9 extending to a solenoid I8 disposed beneath the keyboard, so that upon energization of the said solenoid the connected key lever is depressed to operate'the connected mechanism in the manner just explained.

In addition to actuating the several type bars and connected mechanisms,the revolubly mounted cams are adapted 'to make and break'circuits' Also shown in the drawings is another resistor shunted by a capacity, the resistor spectively.

which may be employed in the transmitting units, the purpose of which will be understood as the description progresses. Upon release of the cam II the ensuing operation thereof causes the contact spring blade 30 by virtue of its attached cam follower roller 3I adapted to engage the cam during its partial revolution, to be urged away from the power roller III to close the contacts 33. Since the cam turns exactly one half of arevolution before being arrested, the spring blade 30 returns to its normal position as shown in the drawings, by ,virtue of its own resiliency, thereby restoring the contacts to their normal open position.

It will be understood that the usual number of key bars and power devices with their associated mechanisms are provided, but only one. of them is shown for the sake of clearness. It is obvious, therefore, that for a simplex system operation the transmitting unit may comprise the device just described including the cam operated switch arrangement, and for the receiving unit,

the device described may be used as shown including the connected solenoids.

. Referring now to- Fig.- 1, one type of circuitwhich may. be employed at the sending station, embodying thedouble impulse system, will now be described. The contacts 33 representing the with each character key bar in the manner just described are segregated and connected in groups of seven.

Each one of the contact members of the different groups of contacts 33 is connectedto a common conductor connecting the said members to individual relays such as .to I4, It is to be noted that the said group of relays comprises separate pickup orenergizing coils and holding windings'or coils, the purpose of which will be understood as the description progresses.

Each one of the remaining contact members of the said group of contacts 33 is connected to a corresponding relay winding of the group of relays 35--I to I. 'The other side of the windings of the last mentioned group of relays are connected by a common conductor 36 to ground. The pickup windings of the relays 358 to I4 areconvarious keyboard characterizations and associated nected to a common conductor 31 through a nornow be traced for a particular character selec-' tion. Let it be assumed that the key bar (Fig. 4) for the character A" is depressed to effect the closure of the corresponding contacts 33 (Figs. 1 and 4), grounded battery 39 is then impressed uwn the following circuit: through normally closed contacts 38, common conductor 31, pickup or energizing winding of relay 35-8, common conductor 40, the corresponding contacts for character A now closed, common conduc tors I and 42, winding of relay 35-2 and common conductor 36 to ground. In this manner, re-' lays 35 -2 and 35-8 are energized to close the associated contacts 43 and 44, 45 and 0,. re-

It is desirable to maintain the particular relay selection until the corresponding character impulses have'been impressed upon the transmission network, and secondly to prevent the poss ble selection and energization of a second group 4 character impulses to betransmitted and com prises a solid'collecti'ng ring 51 and associated Omar another mitted 'to the-receivingstation. One method of efiecting: this as follows: grounded battery- 99 is conneoted gthrough the; normally ntacts' 11,; conductor 19, winding of rea close lay;- 99,

mmoniconductors 59 and, 5i-,-contacts 43 n'ow'clos'ed, winding of relay-It-I and. conductor-.196 to ground. The locking circuit just,

described-is established immediately "upon the energization oi relayfl-Ito maintain the said relay in an operated vconditionuntil the character impulses are transmitted to the connected network; similarly relay -9is maintained in an operative condition due to the connection of] rounded battery 99 to common conductor 5i,

'grounded'battery 391s disconnectedffrom, common conductor 91 which is connected tothe so pickupwindings of relay 95-9'to l9. It is obvious nowthat'the subsequent selection of relays from the groups95-l, to I and 35-9 to. It can.- not be efiected by the closure of any of the contacts 39 until the locking circuits described there- .:for arei broken which does not occur until the character impulses have been impressed -..upon the-transmission networkandyh c now be described.

A transmitting commutator or distributor 59 is;

employed'to-impart particular time values to the brush 59,- a segmented ring 59 comprising a plurality of conducting segments of which there are two main groups, namely, 59-l to .l and 59-9 to M. Two additional segments 59-l5 and 59-l6 are utilized and the purpose of which will become apparent from the following description. A brush 99 is associated with the segmented ring 59. An insulated ring 9| having two conducting segments,-the position 01' which correspond to conducting segments 59-l5 and I9, is

included in the distributor 59, a brush 92 is as-- sociated therewith. Commutators or distributors are old and well known in printing telegraph systems so thatiurther description thereof is deemed unnecessary. The

brushes

59, 59 and 92 are connected together "electrically and may be driven in the usual manner by suitable'means such as a motor-(not shown). In addition thereto conducting rings 99 and 94 are included in the distributor 59 havng insulated segments disposed thereon as shown whielr'are positioned so as to be engaged by the associated brushes 95 and 99, respectivelymvhen the brush 99 is positioned between the conducting segments 59- and 59-i 5. as mentioned before, the brushesll lfl, 62, 65, and 66 are all rotated in unisonby suitable means and in the direction as indicated in the figure. I

The conducting segments 59-l .to l and 59-9 to M. are associated with contacts of therelays 35-! to, l and 35-9 to 19 respectively so that during the proper period. in the distributor cycle 75. "the timed character designating impulses be I 3,174,09 v A untilzthe, preceding character (has been trans'- impressed upon the transmitting circuit. A commen conductor is also associated with the said contacts and connected to one s'ideof the line. The other side of the line is connected by conductor'99 tothe normally open contacts 59*associated-with relay 19 which in turn are connected "to the solid conducting ring 51 of the distributor 59.;- Up tothis point, it is seen that character designating impulses. cannot be transmitted to the said line until at such time the .relay I9 is energized to connectthe oneiside of the line to the said conducting ring 51.

However, relay l9 can'be energized only when the relay p99 is energized, during the timed interval that the brush 69 engages the conducting v segment 59-, and similarlybrush 92 engaging the conducting segment in the insulated ring 9!- corresponding to the segment 59-l9. The said segment in ring 9| is connected to the grid of the discharge tube II and the segment 59-45 is connected to the cathode of said tube through the contacts 53 associated with relay 49. Therefore, it is seen that during the periods when relay 49 is energized and brush 99 engages the conducting segment 59-i9 and at, the same time brush 52 engages the corresponding'segment in ring 9|, 9.

circuit is established whereby the bias on the grid 'of the tube H is changed, which in turn is adapted to start or trigger the tube to permit current to flow in the plate circuit thereof.

- The plate circuit established at this particular timed-interval is as follows: from the positive terminal of battery I! to one of the brushes 95,

solid conducting ring- 99, the otherbrush 95, con-.

ductor 13. winding of relay 10, plate of tube .1! to the cathode thereof and to a negative terminal of the battery. Inthis manner, relay .19 isenergized. opening thenormally closed, contacts 41 line to'the. conducting ring 51.

. The lockingcircuits described and established through the winding of relay 9 are not'broken by virtue of contacts" being opened. due to a shunt circuit established through conductor",

and closing contacts 99 to directly; connect the a conducting ring 59 and brushes 99 and conductor I5 thereby permitting the grounded battery 99 to energize the said locking circuits.

Consequently, durin subsequent en agements of the

brush

5,9 with the segments 59-l to I and 59-9 to it, a closed line circuit condition is established through the contacts of the energized relays. which for the example chosen, it is remembered. are the relays SS-I'and 95-9, when the

brushes

59 and 99 are positioned to engage the particular associated conducting *seaments 59-2 and 59-9. The circuits establish are as follows and in the order described. 0 side of the-line to conductor 91, contacts 9 associated with ,relay'35-2. conductor I9, segment 59-2, brushes 99 and 59, conducting ring 51, conductor TI. contacts 59 and conductor 99 to the other side of the line to close the said transmitting circuit and which is indicative of a character designating timed impulse. L,

Similarly, atan interval later during the same ,cycle. 'the following closed circuit conditionis established to represent anothercharacter desig' nating'timed'impulse, namely, the outside of the 3 line, conductor 9'1, contact 95 associated with relay 35-8, conductor 18, segment' 59-9,'brush'69,

conducting ring, 51, brush-59,1 conductor 11, con-' tacts99 and conductor 98 to-the' other side of the line. r

The efl'ect 'oi the momentary closed'line conditions willdepend upon the-particularapplication of the system, if it is proposed to employ the transmitting circuit described in a metallic line network, the closed line condition may be adapted to alter directly the grid bias of the particular discharge tubes in areceiving circuit to record or register the corresponding characters accordingly, and which is the particular embodiment chosen for an example, setting forth the principle of the invention. However, if employed in a radio network or if desired in a line network, the line terminals in Fig. 1 are connected to the terminals marked transmission line circuit in Fig. 3, which will operate the radio signaltransmitter' to send out an impulse in a well known manner each time the input circuit thereto is closedas described. The receiver is actuated in the usual manner to operate the connected relay closing the associated contacts 8i thereby closing ,the receiving line circuit which is connected to the line terminals of the receiving system in Fig. 2. -As mentioned hereinbefore', the description of the receiving circuit will be effected in the same manner regardless of the type of tron employed, that as in the example to be described for a metallic line in which case the line terminals of Fig. 1 are connected to the line terminals of Fig. 2 or for radio transmission when the connectionsof the circuits Just described are employed.

Before continuing withthe description of the receiving circuit, it is to mention during the timed interval the brushes '00, 00, 62, 05 and 00 are rotated from segment position 69- to segment 00-Ii'the conditioned and operated circuits of the transmitting system are restored to-normal. During this said interval, the brushes 60 engage an-insulated portion or segment 02' disposed in the conducting ring 04, thereby breaking the locking circuit established through the winding of relay 40 and nsequently deenergi'zing relays A0, '4; I storing-the said relays to a normal condition to permit subsequent conditioning of the said relays and similar ones upon the depression-of any character keys to transmit at a later timed interval the character designating impulses.

Immediately after the breaking of the said locking circuits, brushes 0! engage an insulated portion or segment 80 disposed in the conducting ring 'fl'to open the plate circuit described and thereby disabling the tube II by preventing further flow of plate current. Relay I0 is deenergized, as a result thereof, to open the contacts 69, disconnecting the .one side of.the .line

from the conducting ring 01 and closing the engagement of brush 80 with segment 50- and at the same time engagement of brush 62 with the conducting segment disposed in ring 6| corresponding to the segment 00-45 a closed line condition is established directly through the distributor and transmitted similarly as the character impulses, the description of which has just been set forth. 1

Before proceeding with the description of the receiving circuit proper, it may be well to deand 35-8, re-

0 k the switch 05, during the rotation of the distributor brushes,

scribe briefly the synchronizing control circuits which may be employed in the receiving system. Referringnow to Fig. 2, a commutator or distributor 00 is shown developed and similar to the transmitting distributor 56, comprising a segmented ring 00 having disposed thereon ex actly the same number of conducting segments as the segmented ring 00; a solid conducting ring 08 is connected to one side of the incoming line,

and a third conducting ring I00 provided witha limited number of conducting segments, the last mentioned ring used solely for synchroniz' ing purposes. Associated brushes 91, 09 and IOI are rotated by suitable means such as a motor similarly employed-for. rotating the transmitting distributor brushes and are connected together electrically and cooperate with the said rings 96, 00, and I00 respectively. 0

Let it be assumed that the synchronizing switch 05 at the transmitter is closed and that no character impulses are transmitted to the lines and that transmitting distributor brushes and the receiving distributorbrushes are being rotated substantially in synchronism.

It was just mentinoned that with the switch 0! closed at the transmitter, single periodic control or synchronizing impulses are transmitted continuously. The conducting segment 96-45 is,positioned similarlyin the timed cycle as the segment 00-", and segment I00-20 corresponds in position-to segment 06-45, therefore,

it is seen that if the brushes of both distributors are rotating in synchronism, the control pulse transmitted is conducted from one side of the line to conducting ring 90, brushes 99 and IN to unconnected segment I00-20 permitting the brushes to rotate in synchronism. However, if a phase shift occurs so that the impulse is received on either conducting segment I00-2I or "IO-22 representing a slow or fast rotary condition, the corresponding discharge tube I02 is adapted to be ggerated by the changed bias condition of the sociated grid due to the closed line condition, as explained hereinbefore, to start thetube and permit plate current to flow in one of the tubes.

conductor III to the cathode of one of the tubes I02, and from the otherv sideof the line connected to conducting ring 08, brushes 99 and IN to either segment I002I or I0022 to the associated and corresponding grid of one of the tubes I02.- The operation of one of the tubes is then effective to energize either the magnet I03 or I04. The energization of magnet I03 is adapted to retard the receiving distributor brushes until synchronism is established. Similarly, the energization of magnet I04 is adapted to step the said brushes ahead to establish substantial synchronous operation thereof.

7 It is deemed unnecessary to'explain and describe further in detail the specific mechanism to be employed to shift the brushes during rotation to establish synchronous operation, since these mechanisms are old and well known in the art, and for "a complete description of one form thereof reference may be made to a copending application, Serial No. 684,362, filed August 9, 1933 in which the magnets and 56 thereof correspond to the saidmagnets I04 and I 03, respectively, herein.

Provision is also made to properly phase-in the distributor brushes, for example, upon starting the transmitter and receiver, it is possible that the brushes are out of phase by more than the The circuit established is as fol-' lows: from one side of the. line, through common angular position of the correcting. segments I-2I and 23 so that the periodic control pulses are conducted to either segments I00-23 or I 00-24. Under such conditions it is necessary to open the switch I in the plate circuit of the character receiving discharge tubes to. prevent faulty operation thereof and to close the phasingin switch I06 connecting the segments I0023 and I00-24 to the tubes I02, similarly as segments I00-2I and I00-2t to operate the magnets I04 and I08 as just described, thereby retarding or advancing the brushes .until the receiving distributor brushes .are operating in synchronism with the transmitting distributor brushes. The controlimpulse will. then be-conducted to either segment I00-20 representing exact synchronousf operation or to the adjacent segments I00-3I or 22 which as explained will establish the synchronous condition; When this condition is established, switch I06 is opened and switch I 05 is closed and the circuit is conditioned for character signal transmission.

It is to be noted that relays I01 and I08 are included in the plate circuits of the tubes I02,- the purpose thereof, is evident, namely to disable or discontinue the operation of the discharge tubes I0 2 upon energization of .the said magnets I03 or I04. Relays I01 and I08 are adapted to be slow operating relays, to permit the magnets I03 or I04 to operate and adjust the brushes before the associated relay contacts I09 and H0 are operated to open the plate circults of the connected discharge tubes I02. Due to this manner of operation the tubes I02 may be operated successively to energize the magnets I03 or I04 succemively thereby advancing or retarding the brushes step bystep until synchronous operation thereof is obtained.

In thesame figure it is noted that one side ofthe line which corresponds to the side of the line connected to ring 6| in Fig. 1, through common conductor III is connected to a plurality of cathodes of the discharge tubes lI2-'I to I which are of the type described hereinbefore. The other side of the line connected to the solid conducting ring- 00 is connected in succession to segmentsld-I to I4 by the associated brushes 90 and II respectively.

line circuit condition are effective to reduce the grid bias of the corresponding tubes 1 I 2-4 to I;- o co e. depending upon the distributor brush It is to be noted. thatthe grids of the tubes III-I to I are connected to one conducting segment of each-group of segments, for example, the grid of tube 2 4 is connected by conductor II3 to conducting segment l0-I and 0H. Similarly, the other tubes are connected 'in a like manner to the remaining. conducting segments. Therefore, it is evident that the character impulses transmitted and represented by the closed position to determinewhich 'one of the tubes is triggered or started to function at the particular timed interval.

The plate circuit of each of the tubes H2 includes a relay of each group of the relays m-| to I and Iii-I to 'I.. The anode of each tube is connected directly to'one side of the pickup 'or energizing winding of each of'the corresponding relaysythe other side or terminaloi which is connected separately and individuallyto a corresponding brush of the" group of brushes IIIi-I to I4. Thesaid brushes llt andbrushes III are adapted to be rotated in synchronism' with brushes 0!, l0. and iii of the receiving distributor'tl. Onesimplecxpediontistohaveall the relative positions of the conducting segments vII9I to is with respect to the conducting segsaid brushes fixed to the same rotating shaft thereby insuring unison in operation therebetween. The brushes III engage solid conducting rings 0, whereas the individual brushes II6--I to I4 engage short conducting segments II9-I 5 to I0 which are interconnected and staggered as shown. The remaining portion of 'the collecting ringsare insulated, the purpose of which will be understood'presently.

Referring also to'Fig. 5, a chart shows the 10 ments of the distributor segmented ring. It is seen that the brushes BIB-l to I4 will begin to engage the corresponding conducting segments 5 timed cycle that the receiving distributing brush 91 engages the conducting segments 90-I to I4.

It will-now-be apparent that the brushes 6 engaging the associated segments 0 will control the selection of theparticular relay of the group of relays I I4 and H0 associated with the 'I I9,I to I0 at exactly the same moment in the anodes of the tubes It2--I to I.

To continue with the assumed example for the character "A" which is represented by character designating impulses at the 2" and 98" particular timed periods during the predetermined timed intervalcorresponding to a complete dis-. tributor .cycle. Therefore at these particular timed intervals the following circuits are established and in the order described: The closed line circuit condition, while the brush 91 engages segment 90-2, changes orreduces the grid,bias on tube 2-2 to cause the said tube to operate.

The specific circuit for eflecting this condition --val'brush1l62 is engaging segment 9-2) solid conducting ring 8, brush III to the positive terminal of the B"- battery. The negative terminal of the said 3 battery is connected directly to the cathode of tube 2-3, thus completing the plate circuit and due to the current .flow therein relay II42 is energized. The segment IIO--2, similarly as all the segments IIOI to I4, is of such length. was to permit the energization and lockup of the associated relays included in the circuits, which for this particular circuit described is relay 4-2.

It is understood that upon the energization of relay III-2 or anyof the other relays Ill-I to l) I for that matter and upon establishing the looking circuit for the said relay, the plate circuit-of I the tube .PI I292 is opened by the corresponding brush I'IH engaging an insulated section.

The segments m-l' m u, as-mentioned herdnso before are extended enough so that thedischarge tube is maintained in an operated condition Just long enough for the relays inclu'dedin theplate circuit to become energized and locked ,in an operated condition. 'Energizatlon of the said 70 relay causes the normally open contact I30 to be closed establishing a locking circuit from grounded battery I3I, common conductor I32, lockingwinding of relay II4--2, contact I30;

conductor I33, normally closed contact I34 of re- (5 rings Ill and new ground, locking the said re-.

lay Ill-I, conductor I38, brush I, conducting lay Ill-2. Associated with relay Ill-4, and similarly with all the relays Ill-I to I, are a plurality of normally open-contacts Ila-I to I, which areclosed upon energisation of the amociated relay winding and maintained in 8 closed position due to the established locking circuit maintaining the locking winding energised. The

' locking windings oi. the relays Ill-Ito-l once energized remain so for the-major portion'oi the cycle. Reference should be made to Fig. 5-

' than one of the relays at one .time and thus prevent any possible faulty registration 0! characters or the selection of more than one operating instrumentality. f

The second impulse or closed circuit condition is received when the distributor brush '1 is engaging the conductingsegment OH and at this particular timed period the grid bias of the tube II2I is changed to permit operationof the said tube. Due to the position at this moment oi the brushes II, the energized plate circuitis' as follows: irbm' plate of tube II i-I, to conductor Ill, pickup or energizing winding ct relay I I l-l,

cpnductorlll, brush Ill-l, conducting segment I I l8 now engaged by said brush, common connected ring II, brush II'I to-the positive terminal or "3 battery. The negative of the said B. battery'is connected directly to'the' cathode of tube I'll-l The flow or plate current thereby energizes relay Ill-I to permitthe iollowing locking circuit to be established, from grounded.

battery Ill, current passes through conductor III to one terminal of the locking winding of relay II8'-I, the other terminal thereof is connected to contact Ill now closed, conductor Ill to brim-h I36, conducting rings Ill and Ill toground. Due to the length of the conducting portion oi the segment III-l, the plate clrcuit iust described is broken once the said locking circuit .is established. It is tobe noted that the contact arrangement of the relays I II-Y-I to 'I are such that the energization of one relay interrupts ,or opens the locking circuit (or any of the other relays and in this manner'prevents' more than one oi the said relays to be operated at the same time. Energization of relay Ili-l also causes the normally open contact I" to be closed to connect ground throughthe common conductor I ll,

' contact Ill," conductor I, to a group of solenoids It. The said group includes solenoidsfor the operating instriunentalities tor the character can. "A", n. un. uqir' an. and "W". However, it is to be noted that the other terminals of the solenoids all are connected to an open contact with the exception of the "A" solenoid which connected to contact Ill-I now closed due to the energimtion of relay Ill-4. Thus it has been shown how a character selection is made by thepresent-system. It is obvious that any of theother characters desig nated can be selected in alike and similar manher and that iurther. description thereoiis not deemed necessary.

New am the character operating or controlling ineans, namely the-solenoid II, has. been selected, an operating impulse is impressed upon the solenoid circuit to energize it and causethe connected mechanlsmto register the corresponding character. This operating impulse may be transmitted any time in the cycle after the dis-' tributor brushes have engaged all the tube conducting segments lt-I to II. For example, re-

!erring to Fig. 5, the segment I" indicates a suitable period during the cycle to transmit the solenoid impulse and is eilected aslollows:

grounded battery IiI connected directly to a solid conducting ring III is in turn connected to conducting segment III disposed inan insulated ring.

m. Bush in rotated in synchronlsm with brushes lit-I to It and now engages the conducting segment I" to permit current to pass from the said battery through conductor Iii,

closed contact Iii-l, solenoid It for the character-instrumentality for "A", conductor Ill,-

contact ll! now closed, and conductor I" .to ground.

Energisation of solenoid I8 causes for example the character A key bar of the translating unit described hereinbelore to be depressed, thereby releasing the cam unit and causing the A type bar to be operated recording 'the said character.

Immediately D n energization of the said solenoid or any oi the similar solenoids Il, andoperation oi. the said connected mechanism, brush Similarly, brush II. engages an insulated section disposed in-conducting ring Ill for a' brief moment suilicient to interrupt and break the locking circuits established for the relays oi the group of relays Ill and flll'namely relays Ill-I and Ila-I, thus restoring the said relays to a normal condition as shown in the figure. This completes the description for one cycle or operation of the system and it is obvious how iurther and other selections may be initiated and'com' pleted during subsequent cycles of operation of the system.

While there has been shown anddescribed and pointed out the iundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details oi the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit oi-the invention. It is the intention therefore to be limited only as indicated by the scope oi the following claims.

What is claimed is as follows: v 1. In a communication system of the character described. means to transmit character signals,

including-means to initiate two variably timed impulses having similar polarity characteristics I engagesan insulated section oi the ring I" for the remaining period of a complete cycle.

for all characters, means to receive .said impulses successively, and means to select controlling circuits corresponding to the received signals.

2. In a communication system, means to initiate a plurality ot impulses representing various characterise-ti ens, including means whereby all oi said characterizations are represented by the same number of impulses having similar polarity characteristics, means to impart diflerent timevalues to the character impulses, and means to transmit said timed impulses in succession.

T 8. In a synchronous communication system of the character described, means to-transmit a plurality of impulses representing-various charace iaime terizations including control means to impart di1- ferent time values to thesaid impulses, means including means operated in timed relationship with said control means to receive said impulses successively, a plurality of controlling circuits;

means associatedwith said receiving means controlled by one of the impulses to select a predetermined number of circuits'from said plurality of circuits, and means controlled by another of said impulses to effect a selection of a single circuit from the said predetermined number of circuits.

4. In a synchronous communication system of the character described, means to transmit charof circuits from said plurality due to a particular acter signals. including means to initiate a similar number of variably timed impulses for all the characters, meansincludingmeans operated in,

timed relationship with said transmitting means to receive saidimpulses successively, a plurality of-v circuits, means controlled by one of said signal impulses to select a predetermined number timed value imparted thereto-and means controlled by another impulseat a later timed interval to eflect a selection of a single circuit from said predetermined number of circuits.

5. A communication system comprising means to transmit a plurality of impulses during a predetermined timed interval including means to impart difierent and particular-time values to the impulses transmitted during the said timed interval, a plurality of circuits, means including means operated'in timed relationship with 'said transmitting means-to receive said timed impulses including means whereby one o! the timed impulses eflects a selection of a predetermined number of circuits from said plurality of circuits, and means controlled by another of the timed imcircuits and means controlled by another 0! said impulses to complete the selection of the said particular circuit.

'I. In a communication system, means comprising a plurality of operable instrumentalities to effect a character selection, circuit control means connected in cascade controlled by a selected instrumentality so as to be conditioned by the said instrumentality to maintain said characterselec-- tion, and means to transmit character impulses at particular timed intervals in accordance with the said conditioned means.

8. In a communication system, means comprising a plurality of operable instrumentalities to cheat a character selection, relay means controlled by a selected instrumentality to heronditioned'by the selected instrumentality to maintain said character selection, means to transmit character impulses at particular timed intervals in accordance withthe said selection and conditioned means-and means preventing another selection' to )be effected during the timed interval a previous selection is maintained by said conditioned means.

a 9. Ina communication system, means comprisinga-plurality of operable instrumentalities to eil'ect a character selection, relay means con- "applied to the said transmission ell-cuit. V

16. The invention set forth in claim 15 in in trolled by ajselected instrumentality to be conditioned thereby to maintain said character selection, means to transmit character impulses at particular timed periods in accordance with the s'aidconditioned means during a predetermined 5 transmission cycle, and means to restore the said conditioned means to a normal condition upon completion oi the said transmission. cycle. 10. In a communication system of the character described, means to transmit a plurality oi 0 I impulses representing various characterizations including means to impart diflerenttime values to the said impulses, means including means operated in timed relationship :with said trans- 1 mittlng means to receive said timed impu ses. 15

a plurality of controlling circuits, means associated withsaid receiving means to select a particular circuit from said plurality in accordance with the received impulses, and means to prevent a further selection from said plurality of circuits upon the selection of the said particular circuit.

11. In a communication system of the character described, means to transmit a plurality of im-v pulses representing various characterizations including means to impart dlflerent time values to 5 the said impulses, means including means oper-.

ated in timed relationship with said transmitting means to receive said timed impulses, circuit selecting means certain of which are operated by said received impulses and means to prevent the .0

operation of the remainingoi said circuit selecting means during the particular interval the said certain selecting means remain operated.

12. In a synchronous communication system of the character described, means to transmit char- 5 acter slgnals, including means to initiate'a similar'number of variably timed impulses for all the characters, means including means operated in timed relationship with said transmitting means to receive said impulses successively, ciro cuit selecting means and controlling means therefor, said controlling means operated by the said impulses received and adapted to maintain the said circuit selecting means operative beyond the period or application of the said impulses.

13. In a communication system 01' the characcomprising a plurality of variably timed impulses,

circuit selecting means and controlling means therefor, said controlling means responsive to one a or said timed impulsesto operate said circuit selecting means effecting a selection of certain par-,-

ticular circuits and including means so that upon reception oi another-oi said timed impulses the same said controlling means is efl'ective to control is the selection of certain other and dinerent circuits.

i 14. The invention set forth in claim 13 in which the said controlling means is adapted to .maintainthesaidcircuitselectingmeansopere- Q" tive" beyond the period or application or the-said impulses. s

15. A communication system comprising a thermionic device of the type described having input and output circuits, said thermionic deas vice being characterised by continued operation unaiifected by grid pdtentleletter starting. mea s to condition the saidinput circuit at a particular and similar period ineeeh transmissionfielel rendering the said device operative, a trans- 7o mission circuit, and means in the said output circuit controlled whereby signal conditionsmay be ing means to render said thermionic devil 'ter described, means toreoeive character signals a 'sion circuit.

operative upon completion oi the application oi the said signal conditions to the said transmis- 17. In a communication system, means to transmit character signals comprising two or.

more impulses, including means whereby each signal for all characters comprises the same number of successively timed impulses, means to transmit a single periodic control'sig'nal, said 5 8- nals transmitted during apredetermined transmission cycle, means to receive said timed impulses during the said cycle,.an indicating device ,fbfperated by and in accordance with the character signals and'means controlled by said periodic 818itributing-means to receive said timed signal impulses, an indicating device operated by and in I accordance with said character signals received,

operation unaflected by grid potential after start-' ing, including means whereby the said input 'cirand means to maintain the operation or the said distributing means in the said timed relationship and controlled by said periodic signals.

19. The invention set forth in claim 18 in which the means controlled by said periodic sig-' nais includes a thermionic device 01' the type described having input and output circuits, said device being characterized by continued operationunailected by grid potential after starting, including means whereby the said input circuits are conditioned by the periodic signals and the said output circuit adapted to control the operation of said distributing means.

20. In a communication system, means to transmit character signals,

transmit aperiodic character signals and periodic control signals, rotary distributor means to impart particular time values to said impulses, means to receive said timed impulses includingoperated by and in accordance withsaid character signals received, a thermionic device of the type described having input and output circuits, said device being characterized by continued cult is conditioned by the said periodic signals to start the device and means in said output circuit to control the said control means to operate the said distributors in timed relationship, and means to receive the said periodic control signal at any time to control the said thermionic device.

21-. In a communication system, means to transmit character signals," including means whereby each signal for all characters comprises the same number of timed impulses, means to re- "vices have been rendered inoperative. 5

22. In a communicationsystem of the character described, means to transmit character signals comprising the same number or variably timed impulses having similar polarity characLeristics, means to receive said timed impulses, a

plurality oi circuits, means to select particularcircuits from said plurality in accordance with the said received impulses, and means to energize the selected circuits. r

'23. In a communication: system, means to including means whereby'each signal comprises variably timed impulses transmitted during a predetermined transmission cycle, means including means operst'ed in timed relationship with the said transmitting means to receive said timed impulses during the said cycle, a plurality ofcircuits, means to select particular circuits from said plurality in accordance with the said received impulses,

and means toenergize said selected circuits at a predetermined period in said cycle.

24. In a communication-system, means to receive character signals during a predetermined transmission cycle, said signals comprising the same number of variably timed impulses for each character, a plurality of circuits, means including 'means operated in timed relationship with said character signals received to select particular cincults from said plurality in accordance with the said received signals. said last named means adapted to be conditioned to maintain the said selection beyond the period or application of said signals, means to energize said selected circuits.

and means to restore said conditioned circuits to -normal upon ene'rgization oi the selected circuits;

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