US2079440A - Communication system - Google Patents

Description

A TTORN'Y azz INVEN TOR.

C. J. FITCH COMMUNICATION SYSTEM F'lled Feb 9, 1955 Patented May 4, 1937 lTED STATES COMIVIUNICATION SYSTEM Clyde J. Fitch, Jersey City, N. J., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application February 9, 1935, Serial No. 5,768

20 Claims.

'I'his invention relates to communication sys' tems and more particularly to printing telegraph systems and is suitably adaptable to both radio and Wire network transmission.

Insofar as its fundamental features are concerned the methods herein disclosed are applicable to any form of remotely controlled units and particularly adaptable to be used in connection with tele-control apparatus.

The present invention will be explained in conjunction with a single impulse synchronous transmission system, in which the different characters to be transmitted and received are represented by single impulse signals which are definitely allocated during particular timed intervals.

This invention consists of a method and means for the transmission and reception of the translating signals, the system being characterized by utilizing bi-dlrectional controlling signals, in contra-distinction to uni-directional signals. Heretofore the single impulse synchronous systems employed aperiodic uni-directional impulses which involved the shifting of the character impulse along the axis of a timed scale, the position of the impulse thereon determining the character to be selected. Therefore, in systems transmitting a variable number of characterizations such as the representations of a typewriter keyboard, it is yimportant to use impulses of extremely short duration in order to insure accuratel timing and allocation of the various impulses. Transmission speed liniitations are encountered owing to the fact that the rate of transmission is directly proportioned to the speed of the distributing systems.

Increasing the speed of the* distributors also presents acute synchronization diiliculties so that in remotely controlled printing telegraph systems for example, the speed of the distributing systems.

must be operated at such rates that operation of the translating units must be such as to conform to the speed limits obtainable, and'which usually are normally lower than the average rate of operation of such translating units, such as the conventional typewriters used in the present systems.

Reception of the impulses in the uni-directional lsignal systems requires special attention and equipment to properly allocate these signals on the distributing segments to prevent overlapping of impulses thereon, in turn to prevent erroneousl operation of the recording or translating receiver units.

It is these disadvantages just mentioned that the present invention proposes to overcome, which, broadly and briefly consists of the transmission of bi-directional aperiodic, single, im-

pulses applied to synchronous controlling distributors, one method of control being the type using periodic uni-directional impulses for maintaining the synchronous condition thereof. This system permits the controlling segment length of the synchronous distributors to be increased to twice the length used heretofore. It will be obvious to those skilled in the art that the problem of allocating the received signals is simpler in that the margin of operation is greatly icreased. Synchronizing of the rotary apparatus need not be as critical as herebefore, and as will be understood as the description progresses, the rate of transmission of character impulses may be increased proportionately.

It is therefore an object of the present invention to provide an improved printing telegraph system in which signal impu1ses,.distinguished in respect to time, are utilized to select the printing characters.

Another object of the present invention is the provision for the use of bi-directional signal impulses in contradistinction tp uni-directional impulses to control the selecting of the characters to be transmitted and recorded.

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 drawing; and the invention also constitutes certain new and useful features of construction and combination of parts hereinafter set forth and claimed.

In thedrawing:

Fig. 1 shows a transverse sectional view of so much of one type of tele-printing machine as is necessary to illustrate a preferred embodiment of the invention.

Fig, 2 is a diagrammatic circuit diagram illustrating one form and embodiment of the invention.

Translating units For illustrative purposes, this invention is shown as embodying one well known form of translating unit and of the type disclosed in the copending application Ser. No. 676,654, led June 20, 1933, and hence requires only the following brief description.

Referring to the drawing and in particular to Fig. l, in the embodiment illustrated in the drawing, well known means are provided for actuating the type bars (not shown) by power operated devices comprising a power driven roller l0.

A cam ll is pivoted on one arm of a bell crank lever l2 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 lf3. The other arm of lever i3 is connected to the type bars (not shown) in a well known manner and fully disclosed in the aforesaid application.

The lever l2 is actuated by the cam H when the latter engages the driven roller l@ to be operated thereby.' The engagement of the cam il with the power roller is controlled by means of the key lever il in a manner which will now be described.

The cam il isresiliently engaged by a springpressed arm 2U which tends to turn it into engagement with the power driven roller vor stop 2l 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 E@ 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 2t which is provided with an oiset projection 25 at its end -which projects laterally through an opening in the bell crank l2 and engages the bifurcated lower end 2S of an arm 2l of a key lever ll pivoted on the common rod 28.

It is obvious then that depression of a key lever H releases the revolubly mounted cam Ill to engage and be actuated by power roller Il@ in turn operating bell crank l2 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 ll is a connecting link I9 extending to a solenoid l 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 same manner as just explained.

In addition to actuating the several type bars and connected mechanisms, the revolubly mounted cams are adapted to make and break circuits which may be employed in the transmitting units the purpose of which will be understood as the description progresses. Upon release of the cam Il the ensuing operation thereof causes the contact spring blade by virtue of' its attached cam follower roller 3l adapted to engage the cam during its partial revolution, to be urged away from the power roller l0' to open the contacts 32 and close the contacts 33. Since the cam turns exactly one half of a revolution before being arrested, the spring blade 30 returns to its normal position as shown in the drawing by virtue of its own resiliency thereby restoring the contacts to their normal position, that is, contacts 32 closed and contacts 33 open.

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.

General description Referring now to Fig. 2, A represents a printing telegraph unit which may be of the type described or any well known type having a series of character pivoted key bars l'l and adapted to initiate a character impulse when one of the character keys is depressed. The transmitting contacts may be positioned as explained hereinbefore so as to open one set of contacts and close another by the operating cams ll or the contacts may be positioned directly in contact 'with' the keyboard l1 as shown in the figure.

acreage A separate contact 32a is associated with each individual key bar il and connected to segments of the distributor 36, a portion of the development of which is shown and further disclosure deemed unnecessary since their use is well known in the art. Rotary arm 50 driven by any suitable means such as a motor is adapted to engage the segments 35 in rathe-r'rapid succession to cause the transmission of the character pulses. One method of setting' up the bi-directional character signals is by the use of condensers, and as shown an individual condenser 38 is associated with each key bar Il, the said condensers associated with certain of the key bars are connected by a common conductor 39 to the negative side of battery t0, while the condensers associated with certain of the key bars are oonnected by a common conductor di to the positive side of battery dll. It is to be noted that all the contacts 32a, that is, the normally closed contacts, are associated with the conducting segments 35 of the distributor. Instead of associating each character key bar with an independent corresponding segment on the distributor, two character key bars are connected to the same distributor segment, such as the contacts 32a for the character key bars A and N are shown connected to segment 35-i, etc. In this manner, the number of segments 35 on the distributor 3@ may be reduced by half the number for the l same number of characterizations.

Disposed beneath or associated with the key bars ll and normally open are the contacts 33a connected to one side of the condensers 38. These are provided so that when a character key is depressed the condenser 38 normally charged will be discharged by shorting the condenser through contact 33a.

supposing the key bar corresponding to character A was depressed to discharge its corresponding condenser, upon return of the key bar the contact 32a. would be closed to connect the circuit from the negative side of the battery through condenser 38, and the closed contact 32a to its corresponding segment 35i-l, so that when the rotating arm 5B with its conducting brushes d2 engages contact l, a circuit is completed through its other brush @3, solid and common conducting distributor ring M, conductor Q5 and the connected tank circuit consisting of the primary winding of transformer d6 and condenser dl, the other side of said tank circuit is connected to the common terminal of battery im. Therefore, it is seen that upon completion of this circuit just described, by the rotating arm ll engaging the segment 35-l of the distributor, the condenser just discharged by depression of the A character key is now charged negatively through the tank circuit and through the secondary winding of transformer 46 and the connected transmitter the negative pulse is transmitted over the connected transmission network in the well known manner.

Assuming that the character N is to be transmitted, its corresponding condenser 38 is discharged upon the depression of the key bar and through the connected circuit upon the return of the key bar through contact 32a and upon engagement of distributor segment 35--I by the brush 62 of the rotary arm 50 the charging circuit is completed, in this instance, so that the condenser 38 is charged positively through the tank circuit and in this manner cause a positive pulse representation to be'transmitted over the connected network.

Invthis manner it is seen that bi-directional pulses are originated to represent individually different characterizations, and that each char.- acter segment of the distributor completes a circuit for both types of pulses. It is evident therefore that the character signals are not only differentiated by time or rather the transmission of the signals at particular timed intervals but also that these signals are differentiated in character also. f

Of course, it must be understood that the method just described is one form of originating the bi-directional impulses, the condenser discharge method could be used in the same manner, or simply the use of both poles of an E. M. F. source would be eiective to produce the character pulses.

In addition to the transmission of the aperiodic and bi-directional character signals a periodic uni-directional impulse is transmitted as a synchronizing signal and may be transmitted, for example, once each revolution of the rotary arm 50 so that upon engagement of distributor segment 35A-20, a circuit is completed through conductor 48 to the negative side of the battery d0 to transmit a corresponding Signal.

It was mentioned that the condensers 38 were assumed to be normally charged, therefore, in order to insure correct operation of the transmitting system upon starting, the normally closed switch 49 included in the input circuit of the signal transmitter is opened until the individual condensers, which may have been discharged, are charged by having all the distributor segments 35 engaged successively by the rotary arm 50 `in a manner just described, and in this manner prevent erroneous operation of the receiving system which will now be explained.

The broad principle of operation of single impulse systems of the type referred to, as is Well known, depends upon the synchronous operation of the distributing or rotary units associated with the respective transmitting and receiving units. Such synchronizing units are old and well known to those skilled in the art, and therefore a detailed description of this unit is not necessary. It is sulcient to mention that one type of synchronizing units utilizing periodic synchronizing impulses such as, for example, a synchronizing impulse for each revolution of the transmiting rotary dlstributonvusually are arranged so that if the rotary distributor at the receiver lags as compared to the rotation of the transmitting distributor, the receiving rotary brush, by virtue of such lagging engages a contact segment to energize electro-responsive devices by the transmitted synchronizing impulse to cause the rotary arm at the receiver to be advanced to such an extent during its rotation so as to traverse the distributor segments in step with the transmitting distributor. If the receiving rotary arm is leading the transmitting arm, engagement of another con- I tact segment causes the electro-responsive devices to retard the rotation of the rotary arm until synchronous operation is attained. For a complete description of a synchronizing unit of the type just mentioned, reference may be made to the copending application Serial No. 684,362, filed August 9, 1933, patented Sept. 1, 1936, No. 2,053,- 091, which can be embodied in this invention in the following manner:

'Ihe receiving distributor 5I is similar to the transmitting distributor 36 and has disposed thereon the same number of segments 52 which are engaged in succession by a brush 53 attached A the distributor 5 l.

to rotary arm 54 driven by a suitable motor or device (not shown) so that the arms 54 and 50 are rotated synchronously. As previously mentioned, if the arm 54 lags in its rotation, and assuming upon reception of the periodic synchronizing impulse transmitted by the distributor 36, the brush 53 engages the segment 52-2Ila, a circuit is then completed through the synchronizer 55 and brush 56 and its associated conducting ring 51 to cause the synchronizing unit 55 to advance the rotary arm 54 to rotate in synchronism with arm 50. Similarly, if the arm 54 is leading arm. 50, assume segment 20D is engaged by brush 53 upon reception of the synchronizing impulse, the synchronizer is energized by the circuit completed through the said segment to retard the rotation of arm 54 to again rotate synchronously with arm 50. Unless otherwise specied in the description hereinafter, it is assumed that the arms 50 and 54 are operated in synchronism so that the like segments of the distributors 36 and 5I are engaged by the associated brushes simultaneously.

A transformer 59 associated with the line cr radio receiver 60 which is adapted to receive theaperiodic bi-directional character pulses and periodic synchronizing pulses transmitted by the transmitter 6|, has its primary winding connected to the output circuit of the said receiver.

The secondary winding of the said transformer has each of its terminals connected to the grids of thermionic tubes 62 and 63. The plates of these tubes are connected to series related primary windings of transformers 64 and 65, the secondaries of which are connected to amplifiers 66 and 61 respectively which in turn are interconnected by common conductor 68 connected to the common conducting segment ring 51 of The separate conductors 69 and 10 from the amplifiers are connected to separate groups of the typewriter solenoids I8; for example, as'shown, the group of solenoids connected to character key bars for A, B, and C are commonly connected to amplifier 66, and the group of solenoids for characters N, O, and P are connected by conductor 10 to amplifier 61.

The other terminals of the solenoids I8 are connected to the individual segments 52 lof the distributor 5i, each solenoid in a group as the solenoids for characters A, B, and C are connected to segments 52-I. 2 and 3 respectively; the terminals'of the solenoids I8 of the second group N, O, and P are likewise connected to the separate segments 52-l, 2 and 3, so that two character solenoids are connected to each segment, and the solenoids so connected represent the same characters as are representedby tlie 'duo-connections to the transmitting distributor segments from the contacts 32a associated with the character key bars l1.

A power supply, generally indicated at 12, supplies the elements of tubes 62 and 63 with the proper potentials, as indicated in the figure so that upon reception of a positive pulse representative of a character tube 63 is energized thereby activating its connected output circuit, namely transformer 64 and amplier 66, similarly a negative pulse causes the energization of tube 62 to activate its connected output circuit, transformer 65 and ampliiier 61. Normally, when no pulses are received, the grid elements of tubes 62 and 63 are biased so that an inappreciable amount of current ow exists in its separate output circuits so that the solenoids I8 connected as described hereinbefore to the amplifiers 66 and 61 are not energized when the rotary brush engages the various segments 52. Upon reception of a character pulse, one of the tubes 62 and 63 is energized due to the grid swing caused by the incoming pulse, depending on the character of the incoming pulse. The operation of tubes connected in the manner described is well known in the art and further description thereof is not deemed necessary.

Assuming that the pulse corresponding to character A is received, and as explained this pulse is formed by the negative charging of condenser 38 associated with the character A key bar l1, tube 62 is then energized to activate the connected transformer 6i and amplifier 66, and since it is understood that brush 53 is engaging segment 52-1, a circuit is completed through solenoid i8 representing character A, by conductor 69, conductor 15, segment 52-l, brush 53, brush 56, common segment 51, conductor 16, to the return conductor 68 of amplit. 66, energizing character solenoid representing A.

The energization of the said solenoid depresses the correspondingly linked key bar I1 (Fig. 1) to release the revolubly mounted cam Il to engage and be actuated by the power roller HJ in turn operating the associated bell crank t2 and its attached links and mechanism to operate the type bar corresponding to character A and recording the said character accordingly.

Similarly, depression and release of the key bar l1 representing character N of the teleprinter A causes the associated condenser i8 to be charged positively through the tank circuit thereby causing the transmitter 61 to send out a pulse representative of this character at its proper time in the cycle whenthe rotary arm 50 of distributor 36 completes the said charging circuit through the conducting segment 35-I. Therefore, it is seen that for characters A and N, the pulse representations are characterized by the time of transmission during a particular timed interval represented by the complete revolution of the rotary arm 5D, the timed period in this predetermined interval representing by this characteristic two different representations.. The second differentiating characteristic of the representations is the character of the pulse transmitted during the particular timed intervals selected, to control the final selection of the particular character at the receiving or recording unit B.

Upon reception of the pulse representations of the character N by the receiver 60, Aand upon energization of the connected transformer 59 by the characteristic pulse, tube 63 is energized to activate transformer 65 and the corresponding amplifier 61 to energize the circuit connected to solenoid N through conductors 'I0 and 15 segment 52|, brushes 53 and 56, common conducting segment 51, and conductors 16 and 68, whereby the energized solenoid I8 depresses the key bar I1 to operate the character type bar and record the particular selected character.

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

What is claimed is as follows: 1. In a communication system, means for transmitting character impulses including means to initiate impulses of equal timeduration but differing in character during a predetermined timed interval and means cooperating therewith to control the initiation of the impulses at differential times therein determining the selected characters to be transmitted, and indicating means adapted to be operated by the transmitted impulses in accordancewith the character and time of reception of the said impulses to select the particular character represented thereby.

2. In a communication system, means to initiate single impulses of equal time duration but differentiated as to character to represent various characterizations, means cooperating therewith to control the initiation of the said impulses at differential times during predetermined time intervals determining the selection of particular characterizations and means to transmit the impulses diierentiated as to time and character representing the selected characterization.

3. In a communication system, means to transmit character impulses of equal time duration having different characteristics including cyclical- 1y operable means for initiating impulses at differential times during predetermined timed intervals representing different characters, and controlling means cooperating therewith to select the character of and timed intervals at which the impulses are initiated in accordance with the various characters to be transmitted, and means adapted to be operated by the transmitted impulses and in accordance with their selection.

4. In a communication system, 'means for transmitting character impulses of equal time duration having different characteristics including cyclically operable mechanism for initiating `current impulses at differential times during predetermined timed intervals to represent different characters, each by a single differentially timed impulse and controlling means cooperating therewith to select the character of and times at which the single character impulses are initiated in accordance with the diierent characters to be transmitted, and means adapted to be operated by the transmitted impulses and in accordance with their selection.

5. In a communication system, means for' transmitting aperiodic signal impulses of equal time duration but of unlike character representing various characterizations, means for transmitting periodic impulses of like character, means U.

for receiving the said impulses including means controlled by the said periodic impulses of like character and means controlled by; the aperiodic sent different characterizations, each by a single selected impulse, means for transmitting periodic impulses of like character, and means for receiving the said impulses including means controlled by the said periodic impulses of like character and means controlled by the aperiodic impulses of unlike character.

8. In a communication system, means for transmitting bi-directional character impulses of equal time duration to represent different characterizations, each by a single selected impulse, means for transmitting uni-directional synchronizing impulses, and means for receiving the said impulses including means controlled by the uni-directional synchronizing impulses and means controlled by the bi-directional character impulses.

9..In a communication system, a plurality of stations, each of said stations having a contnuously operated control device, the operation of each of said control devices being in timed relation with that of the other, means to select impulses of unlike character to represent different characterizations, each by a single selected impulse, means whereby the said selected impulses are transmitted from one of said stations at instants of time governed by the operation of its said control device, and indicating means at another of said stations responsive to the said impulses, said indicating means being governed by the control device associated therewith.

10. In a communication system comprising a plurality of stations, each of said stations having a continuously operated control device, the operation of each of said control devices being in timed relation with that of the other, means to select bi-directional impulses to represent diEerent characterizations, each by a single selected impulse, means whereby the said selected impulses are transmitted from one of said stations at instants of time governed by the operation of its said control device, and indicating means at another of said stations responsive to the said impulses, said indicating means being governed by the control device associated therewith.

11. A communication system, in combination, a signal impulse transmitter, translating units comprising signal transmitting instrumentalities, control devices comprising a plurality of controlling members, a plurality of said instrumentalities associated with each of the said controlling members, energy supply means associated with the said instrumentalities whereby the operation of one thereof selects the character of the signal impulse to be transmitted, and means included in ythe said control devices governing the transmission of said selected signal impulses.

12. A communication system comprising means to transmit signal impulses, including 'a translating unit comprising signal transmitting instrumentalities, a. control device comprising a plurality of controlling members, a plurality of said instrumentalities associated with each of the said controlling members, energy supply means associated with the said instrumentalities whereby the operation of one thereof vselects the character of the signal 'impulse to be transmitted, and means included in the said control device governing the transmission of said selected signal impulses, means to receive the signal impulses, a second translating unit comprising a-plurality of signal receiving instrumentalities, a control device comprising a plurality of controlling memincluded in the last mentioned control device governing the operation of the said selected receiving instrumentality.

13. In a communication system, a translating unit comprising a plurality of operable instrumentalities, means to select signal impulses differing in character upon operation of the selected instrumentalities, means to store the selected signal impulse, and a control device including means governing the transmission of the said selected impulse stored by the said storage means.

14. In -a communication system comprising means to transmit signal impulses of different character,'a translating unit comprising a plurality of operable instrumentalities, circuits con- -trolled by said instrumentalities, storage devices included in said circuits, whereby the operation of the selected instrumentalities condition the said circuits and storage devices for the selection of the signal impulses unlike in character, and a control device including means governing the transmission of the selected impulses.

l5. In a communication system comprising means to transmit signal impulses of unlike character, a translating unit comprising a plurality of operable instrumentalities, circuits controlled by said instrumentalities, electrostatic means ineluded in said circuits, whereby the operation of the selected instrumentalities condition the said circuits and electrostatic means for the selection of single signal impulses unlike in character, each impulse indicative of definite representation, and a. control device including means governing the transmission of the selected single impulses.

16. In a communication system, means to receive signal impulses of unlike character, a control device comprising a plurality of controlling members, a translating unit comprising a plurality of signal receiving instrumentalities, of

Awhich a plurality are associated with each of the laccordance with the character of the signal impulse received.

17. In a communication system, means to receive signal impulses of unlike character comprising a plurality of electrostatic devices of which a predetermined number are responsive to signal impulses of predetermined character and the other electrostatic devices responsive to impulses of different characters, and indicating means capable of performing independent operations, which are controlled by the character of the impulses received.

18. In a communication system, means to receive signal impulses of unlike character, a translating unit comprising a plurality of signal receiving instrumentalities, a plurality of electromagnetic devices associated with said instrumentalities, a control device comprising a plurality of control members to each one of which are connected two of the said electromagnetic devices, and means included in the said control device governing the energization of the electromagnetic devices selected in accordance with the character of the signal impulses received.

19. A communication system comprising means to transmit signal impulses, including a sending unit comprising a plurality of operable key instrumentalities, a circuit control device comprising a, plurality of contact members and a ro-f tatable contact arm adapted to engage the said contact members successively, a plurality of circuits connecting a predetermined group of said 6 acreage key instrumentalities to each of the said contact members, energy supply means associated with the said instrumentalities whereby the operation of one selects the character of the signal impulse to be transmitted, the time of transmission controlled by the said rotary contact arm, means to receive the signal impulses, a receiving unit comprising a plurality of printing control instrumentalities, a circuit control device com- 10 prising a plurality of contact members and a rotatable contact arm adapted to engage the last mentioned contact members successively, a plurality of circuits to connect a predetermined group of the said printing control instrumentalities 15 to each of said last mentioned contact members,

and means associated with the said receiving means to select one of the said group o printthe said circuit and adapted to store the selected impulse accordingly, and a circuit control device governing the transmission of the said selected impulse stored by the said storing means.

l CLYDE J. FITCH.

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