US1944565A - Transmission of printer signals by radio - Google Patents

Description

Jan. 23, 1934.

R. E. MATHEs TRANSMISSION OF PRINTER SIGNALS BY RADIO 1932 4 Sheets-Sheet 5 Filed Sep-t. l5

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INVENT'OR n.5. MATHES ATTORNEY l Jan. 23, 1934.

R. Et MATHEs ATRANSMISSION OF PRINTER SIGNALS BY RADIO Filed Sept.

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f/c/rfs 4 Sheets-Sheei'l 4 Fil/1 X5 VBY man fof/mers of up; wlan/frias INVENTOR R. E.. MA HES ATTORNEY Patented Jan. 23, 1934 UNITED STATES TRANSMISSION oF PRINTER sIGNALs Br Y. mimov I Richard E. Mathes,'Westiield, N. J.,rassgnor to Radio Corporation of America., a corporation of Delaware Application September Serial No. 633,257

s claims. (ci. 17a-52) This invention relates to printing telegraphy, and is especially concerned with communication circuits for the transmission and reception of printer signals. 1

A primary object of the present invention is to provide a system capable of automatically relaying, by radio or wire line, signals from startstop printer mechanisms, such as stock ticker signals.

A further object is to obtain secrecy and accuracy of communication, and this is accomplished by a storage arrangement for automatically repeating each signal character at intervals a predetermined number of times.

A more specific object is to enable the transmission of the 8-unit code such as is used, for example, by the New York Stock Exchange ticker system, by means of a synchronized 6-unit code. The invention, however, is not limited in its use to 8-unit stock ticker signals, since it may readily be employed with code signals having any desired number of units, such as the 5-unit code which is in general use in systems employing printers of the wellknown Kleinschmidt or Teletype type.

A feature of the invention residesr in the means employed for converting start-stop signals to av synchronized code for transmission, and subsequently reconverting the received synchronized signals back to startstop characters.

Another feature resides in the control of the automatic tape transmitter f/rom the synchronized multiplex apparatus.

In a particular embodiment of this invention the printer signals are fed into a reperforating device which functions to discard the start and l stop signals received from the linev and to convert the message characters into a tape record which in turn actuates an automatic tape transmitter under the`control of a multiplex transmitter.,

The latter may be of any desired type, but in the preferred arrangement, in order to avoid fortuitous distortion, such as may be due to line noise, cross talk, interference, static, or fading, it is one' which provides for the repeated transmission .of each unit character two or three times at intervals which are rather long compared with the lengt-h of the unit character, At the receiver these several repetitions are stored until the last one has been received. Then they are automatically compared and the distortions, which did not occur on all of the several repetitions are rejected, and the resulting clean signal is passed on to the retransposing or printing mechanism.

One advantage of such an arrangement is that it permits the transmission and ultimate reception of stock ticker orstart-stop printer signals over circuits of approximately all types inwhich heavy vdistortion is apt `to be encountered with a sufciently high degree of accuracy to meet the desired strict requirements of communication systems. l A modication of this invention utilizes an electrical contactor device in combination with suitable relay apparatus and a phase corrector in place of the mechanical tape reperforator. From this it will be evident that, if desired, the reperforator mechanism may readily be replaced by any other suitable electrical y arrangement.

The'invention is described in more detail in the following description which is accompanied by drawings, wherein: i

Figure 1 illustrates, diagrammatically, one method of practicing the' present invention; and

y Figure 2 illustrates a modification thereof.

Figure 3 shows, schematically, a suitable reperforator which may be employed for converting 8-unit code signals to (1i-unit tape reperforated signals.

Figure 3a shows in more detail the operatic of the selector bar and magnet of the reperforator of Figure 3. v

Figure3b is a modification ofthe apparatus of Figure 3 and illustratesthe use of electrical contactors instead of the punch mechanism.

Figure 1i illustrates, schematically, a multiplex transmitting and receiving system of the pre--4 ferred type.

Figure 5 shows a special distributor adapted to convert synchronized 6-unit signals into startstop 8-unit characters; and q Figure 6 shows a master distributing relay circuit for transmitting signals to a plurality of tickers. l

Referring to Figure 1, there is shown, by way of example only, one particular method, in accordance with the teachings of the present invention, of using a start-stop system with a syn- `chronized multiplex transmitter for automatically relaying printer signals. Stock ticker start-'stop signals of the S-unit type are received over the line L from the regular master ticker transmitter customarilyl used to transmit the stock ticker` signals to the various receivers lo-n cated in the different brokers oiilces and fed into unit B, which may be any well known type of reperforator which is slightly modified `'to perforate the tape in the 6-unit code used by the ticker service. This reperforator, later det scribed inmore detail in connection with Figure 3, discards the start-stop pulses and records the actual message characters on tape 3 in 6-unit characters, which in turn is fed into automatic tape transmitter unit C. Perforated tape 3 isV in the form c! a slight `loop and acts as a storage reservoir to equalize thevarious time intervals between thek ticker signals and the automatic tape transmitter C. Such storage reservoir has been found necessary since there is no assurance that each letter combination will occur at a time interval which is an integral4 number of units equal to the length of one letter, particularly so since the signal is to be impressed upon a multi- .plex system wherein each character must be compressed to a time length equal to the time of a distributor revolution divided by the number of sections or channels per revolution. This compression is effectively accomplished by the tape in conjunction with unit C.

Unit C is an automatic tape transmitter of any well known satisfactory type such, for example,

l as the Siemens automatic transmitter or any of those described by H. H. Harrison in his book on Printing Telegraph Systems and Mechanisms (1923) pages 172 Vto 187, except that those referred to are for the 5-unit tape,` instead of for the 6unit tape. Since vthe principles of construction and operation are the same, itv is, of course obvious to anyone skilled in the art that such a transmittercan just as readily be made up for 6-units as for 5 units.

From the automatic tape transmitter the signals are passed on to unit D which may be any not necessary, however, that this unit operate from a start-stop signal since it may be arranged to operate from a cadence signal from unit U.

The perforated tape sent out by unit W controls another unit X which is an automatic tape transmitter modified for 6-unit tape and func-f tions exactly as does unit C. Inlthis case, however, the tape and auto combination are `eiective in lengthening the time duration of the character in order to fill in the interval previously used by the repetition channels and thus restore the G-unit characters td the same length they had at the originating tickertransmitter.

type of multi-channel multiplex transmitter, but

in the preferred embodiment is one which functions on` the Verdan principle for the elimination of static or fading on radio circuits or for the elimination of yother types of distortion on wire telegraph systems.- The Verdan principle Jof signal character repetition is well'known in the art land is adequately described in United States Patent No. 1,677,062, granted July 10,1928, to C..Verdan and L. Loiseau. Multiplex unit D is a special type of multiplex channelling arrangement and consists essentially of two parts as described subsequently in connection with Figure 4: first, a standard multiplex distributor which provides several channels of the time division type; and secondly, a' special distributor system associated with asignal storage system which functions to store up a portion of the transmitted signal for a period of 'time of the order 0L some 211 seconds. At the end of that period these stored signals are returned to andther channel of the multiplex transmitter and are again transmitted to the distant station. Present practice for Verdan systems seems to have standardized on the original transmission and two repetitions, though this limitation is by no means inherent, and the number offrepetitions used .may be chosen to meet the particular operating conditions.` For present purposes the unit D should bemodied to provide, say, three 6`unit channels on the multiplex distributor and j a 6-unit storage system. From unit D the signals go to control the communication circuit here' designated a, be it radio, carrier, or wire line. At the distant end these signals are received .by well 'known meth-- y one has been received when they are automatically compared and only thoseunitf the code character which have been perfectl received on all transmissions are passed on to e selecting relays of unit W. Unit characters not received on all transmissions, and which are the result A special distributor is now provided yto supply the. start pulse, pass'the 6 units set up at the automatic transmitter, and vsupply the stop pulse,

all successively, in a manner to be described later in morev detail. This distributor is designated as unit Y and is driven at the same rotation speed as the multiplex. distributor of unit U. By this operation there is reproduced the'tickeror printer signal in exactly the form in which it rst reached unit B from the stock ticker or printer vsmooth outy unequal time intervals.

transmitter. This signal may now be distributed to the receiving tickers which are of the standard recognized form. c f

Referring to Figure 2, there is shown a modil cation of the present invention wherein reperforator unitB is modified to provide an electrical i contactor device instead of a perforating punch machine. 'I'hese contacts, which are illustrated in Figure 3b, areV connected to unit D in lieu of the contactsof the automatic tape transmitter. Sucha system may be used if the originating transmitter is of the cadence type. Y In this case the start of each character is always a time interval later than the start of thepreceding character, which interval is an integralmultiple of the duration of a character. Therefore, the storage action-of the tape is no longer necessary to The compression eifect is obtained from t/he storage inherent in the relaysof the reperforator.

Inasmuch as the modied system is now operating 'from a cadence type of transmitting system, it`becomesnecessary to consider the transmitter' for purposes' of speed and phase adjustment as a master'station for the entire system, and for this purpose a phase and speed correction system -is provided in unit -E to maintain the. multiplex transmitter commutators in speed 'f and proper phase. This system, which' functions elements, does not require the transmission of `any sort ofv special correcting signal from the of the fortuitous distortion which is inherently random, are rejected and are thusineective to set upthe relays oi' unit W erroneously. Unit U transmitting or originating station. Phase corthe art and are adequately described, forv exam- Ato produce the proper correction from the signal ple. by Harrison hereinabove referred to, on page force their individual punches through the paper relays are arranged to be connected directly with the signaling segments of the special distributorV unit Y. v

In order to permit distribution to a multiplicity of tickers and ticker loops, unit G has been proided'as a heavy duty master relay system to be operated from the special distributor unit Y in a manner shown in Figure 6. It has been found that the distribution of the signals to the tickers cannot be effectively accomplished directly from `the distributor because of the large amount of power necessary to be handled for such distribution.

One major advantage of the system o f Figure 2 resides in the elimination of the considerable delay inherent inthe loops' of reperforated tape. With such an arrangement the'delay is reduced to a certain low minimum inherent in one character storage in units B andW and in the approximately 4 seconds delay inherent in the Verdan storage system.

In Figure 3 there is shown reperforator apparatus suitable for use in unit B. In this gure is shown a distributor commutator having a brush arm 10 driven by a motor 11, the speed of which is controlled in accordance with Well known practice in the printer art. The speed is so chosen that brush arm 10 willrotate at a speed slightly faster than that corresponding to the incoming printer signals. The commutatorhas been provided with six signalling segments and, in addi-v tion, with a start-segment and a stop-segment lto ,correspond with the eight units constituting a letter or character as produced by the transmitting system. Each signalling segment is assigned to lan individual selector magnet a. b, c, d, e or f in such a manner that as brush arm l0 rotates insynchronism and phase withl the transmitter the signalling units emanating therefrom will be routed to the various selector magnets in succession and will cause these magnets to function, depending upon whether the unit signal received from the transmitter is positive or negative. If the signal is positive the corresponding selector magnet will attract the armature and in so doing will complete a self-locking circuit through the back contact of the restoring magnet Ml to a positive potential indicated in the drawings by a plus sign. As will be seen in Figure 3a, this also causes the tip of the selector magnet armature to fall opposite the slot in the selector bar. Upon completion of the reception of the six signalling units the brush of the distributor then passes on to the stop segment which supplies a positive potential from the receiving line relay through the brush'arm and segment to the punching magnets, thus attracting all six selector bars. Those bars for which the selector magnets have not been actuated by the received signalling elements are prevented by the magnet armatures from travelling toward the punch magnets and, therefore, do not actuate their punches. The other selector bars are permitted to travel toward the magnets and in so doing tape, thus producing perforations in the ltape in accordance with the combinations of the six signalling units received from the `Ydistant transmitter. A special circuit utilizing a slow releasequick operate magnet M3 is provided to close an' auxiliary circuit to 'cause the reperforator to punch center holes only for a length of time equal to the loop between the reperforator punfch and the auto pins. Relay M2 may, for example, be vcaused to operate on 5 second intervals.

.fortuitous distortion' on telegraph systems.

Such an arrangement will not cause an unwarranteddelay due to live punched tape being held in this loop when the ticker experiences a longpause. Other auxiliary, circuits may be provided to feed such blank tape at a higher Vrate than live, punched sections.

As the brush arm continues its rotation it' comes in Contact with a shortv auxiliary segment setI between the start and stop segments. This permits a -positive pdtentia1 to be applied from the receiving line relayvthrough the brush arm the well known manner, to permit of its being stopped by the detent while the motor continues to run. Brush arm 10 will remain stopped as long as the stop unit persists 'in the receiving line relay in accordance with the signal received from the distant transmitter.V However, as soon as the distant transmitter'sends the start unit of the next succeeding character, the tonque of the receiving line relay will move from its positive to its negative potential contact and will thereby complete a circuit Athrough the brush arm and a second auxiliary contact carriedy on an inner ring of the distributor to actuate detent magnetMZ which then attracts its armature and permits the brush arm to again commence rotation.

At the,

It will thus be seen that brush 10 makes one .l

rotation for each character received from the distant transmitter and will cease moving upon completion of one rotation unless and until the start of the next character is received from the distant transmitter. The result is the production of a reperforated tape bearing only the sixsignalling units which omits the start unit and stop unit and also prevents the occurrence of false characters such asialse spaces on the tape through delay at the transmitter in sending a succeeding character.

Obviously, many other circuit arrangements may be used for the actual perforationas well as other forms of distributors.

The tape thus produced by the reperforator of Figure 3 may then be fed into a six unit automatic tape transmitter with a loop of tape intervening transmitter` which employs the Verdan principlefor the elimination of static or other types of particular system shownaccomplishes the stor- The age of signals through the medium of condensers instead of through mechanical means, and shows the connection for the rst unit of a six unit character. 'tor is in accordance with standard practice for such transmitters and is provided with 20 segments.' The first 'six constitute one channel; the

following six a second channe1;' the next six a third channel and the remaining two are used.)

The transmitting multiplex distribu- 1;1 `f

. for the purpose of sending a correction signal' which is utilized in the maintenance of phase between the Areceivingdistributor and the transmitting distributor in accordance with any of ythe is an auxiliary o r transmitting storage commyments to the outgoing line relay 18 and permitstator. The relationship between the two commutators lis s uch that when the rst unit-of a character is set up in the automatic tape transmitter, positive or negative potential is applied through segment 1D, the brushes, and segments 1G and 1H to charge condensers C1 and C2, At the same time, this potential is applied through the brush of the storage commutator to segment 1A of the multiplex distributor from which it is passed through its brushes to the outgoing line relay 18. The eiect of such action is that the. signal unit set up atethe tape transmitter has been transmitted to the line and, simultaneously, has been stored on condensers C1 and C2. `At some later time, which is determined'by the gearing ratio between the multiplex distributor and the storage commutator, brushes of the latter come in contact with segment 1E at the same time that, the

brushes of the multiplex distributor are in contact with 1B. This completes 'a circuit from condenser C1 through the above mentioned segthe condenser to dischargev therethrough, thus resulting inagain transmitting this same unit to the line. After an equal interval of time, brushes of the storage commutator are in contact Awith segment 1F at the same time that brushes of the multiplex distributor are in contact with segment 1C, thus completing the circuit from C2 through these segments to the line relay 18 which permits the condenser to discharge and thus transmit to the line for the third time the unit as set up by the tape transmitter. Y

In this manner the rst signal unit of a character is transmitted over the communication circuit. It will be understood, of course, that similar actions take place through segments 2A, 3A, 4A, 5A and 6A in succession, and that separate storage commutators and separate condensers are provided for each of these'six units.

- the receiving equipment corresponding to the From the foregoing it will be seen'that thus far signals have been received from start-stop printer .transmitter mechanism and reduced to six units by omitting the start and stop pulses, that the tape has been -perforated bearing these six units, that this tape-has been analyzed and the .six units `transmitted through the multiplex transmitter to the `outgoing circuit.

These signals are received by unit U which is nals assent from the multiplex transmitter together with any additional signals d ue to fortuitous distortion. The contacts of relay 19 are arranged so that for lnegative signals, potential from the battery 20 will be applied through the relay to the brushes of the multiplex distributor. When the brush hascome in contact with segment lA'thebattery circuit will be completed through segment 1A, brushes of receiving'storage cmmutator and segment 1D to charge 'the condensernCS. At some later time equal to the time of delay at the transmitter, the distributor brush of the receiving distributor is `in contact With /segment 1B coincident with `,the receipt `by tne line relay 19 of the second transmission of the unit signal. This vagain completes the circuit through the relay and segments 1B`and 1E to again charge condenser C3. After a further time interval the multiplex brush is in contact with segment 1C when the third transmission of the unit arrives at the incoming line relay. This again causes the circuit from the battery to be completed through segments 1C and 1F to again charge the condenser. However, at this same time the brush of. the receiving storage commutator is also in contact with an auxiliary segment 1G which is connected through a'relay 21 back to the opposite side of C3. This closure permits the discharge of C3 through the coils `of the output relay 21 to` actuatethis relay in accordance with the polarity of the received signal unit. Now, if during any of these three transmissions distortion had been present and of sufficient amplitude to operate the incoming line relay 19, its tongue would have been on the upper contact instead of on -the lower and,

therefore, the condenser C3 would not have been ,Herein resides the application of the Verdan principle. The signalling units are transmitted over the communication circuit as negative or no-current pulses and the spacing units are transmitted as positive or mark pulses. Consequently, distortion due to noise or static must produce at the receiver an action similar to that produced by the spacing signal' at the tape transmitter. f

If desired, the coils of the output relay 21 conlli) nected to condenser C3 may be replaced by a condenser arrangement. .The reperforator and automatic transmitter at the receiving end 'only couldthen be omitted. Such an arrangement may consist of six-condensers or relays for 6- unit code operation, which would be energized by the output 'from the mux receiver and thus caused to store pulses until they could be analyzed and passed to the output of the special distributor. An advantage of such arrangement resides in the simplification of the 'equipment and in the elimination of the delay inherent in the loop of tape between the reperforator and the automatic tape transmitter. In Figure 5 is a special distributor corresponding to unit Y designed for the purpose of re-inserting the start-stop pulses before and after the receipt vsix signalling units of the character in order to permit the output circuit to operate the original start-loop recorder. v'I'his distributor` is carried on the same shaft as are the commutators of the ymultiplex receiver or on a denitely associatedY or synchronized shaft. The gearing to the brush of this distributor is such that it will make one revolution-for every revolution of the `multiplex distributor.\` Six signalling segments are each connected to their respective contacts on the automatic tape transmitter unit. Positive potential is connected to thestop segment and negative potential isconnectedto the start segment. As the brush arm 13 revolves it will send a start pulse and then send the sixsignal units in accordance with-the position of the contacts which in turn are de- 'gli tomatic tapetransmitter, designated as C in Figreceived signal to the six output relays.

"other type of means f`or termined by the reperforated tape. Upon completion of this the stop unit is transmitted. The result of this action, as will be evident, is to transmit thesix units/together with start and stop pulses infa regenerated form identical with the signalsreceived'by unit B from the startstop transmitter.

If desired, instead of the perforationl of holes in the tape one may substitute electrical con-l tacts for the paper punches in a manner shown in Figure 3b. It should be obvious that this substitution will result in selection of plus or minus potentials ,by the selector bars. The contacts carried by the individual selector bars are -then connected directly to the individual segments of the transmitter storage commutator. In other Words, these contacts are substituted rfor the contacts of the automatic tape transmitter shown connected to the circuit of Figure 4. n As regards the operation of the apparatus in unit F in Figure 2, it is necessary that an auxiliary contact designated as Q in Figure 4 be in it makes contact with segment Q, positive potential is supplied through this segment to a second Winding on the output relay and thence back to minus and causes tongues of all output relays to be returned to their upper contacts. The position of the brush on the distributor, Figure 5, is so positioned that contact with its segment Q occurs when the special distributor brush is on the stop segment. 'The effect of this is to permit the operation of the output relays to take place at a time when the special distributorl brush is not analyzing any ofY the six segments and, therefore, will not cause interference or errors with the output signal from the system.Y

tems. Furthermore, anyC 'form of apparatus may be used which incorporates the Verdan principle of automatic repetition and storage, such apparatus utilizing, for example, storage in the form of pin drums or disks, steel tapes ,upon whicl 'lsig nalsl aremagnetically recorded, condenser b'anks'eIectrQ-magnetic relays, or .any

storing signals for subsequent repetition.v`

In the interests-of greater secrecy, one may, if desired, reassigndifferently the pins of the auure 1, to the segments of thetransmtting Amultiplex distributor, and reciprocally reassign the segments of the. receiving distributor to the magnets of the reperiorator in a. predetermined manner. Theoretically, there are about 720 possible :arrangements `oi? these contacts.

When

signals.

1. In a printing telegraph system havingstartstop printer mechanism and synchronous apparatus for transmitting signals received from said start-stop mechanism, the method of transmission Which comprises, translating start-,stop

printer signals into synchronous type of signals,

transmitting each of lthe synchronous type of signals at predetermined intervals a plurality of times, receiving and storing said synchronous type of signals, and subsequently reconverting said synchronous type of signals into start-stop printer signals. y

2. `APrinting telegraph apparatus having, in combination, printer mechanism for transmitting multiple unit code signals having start and stop pulses, a reperfortor unit for receiving said multiple unit code signals, said reperforator being arranged to record the printer signals on tape and to `discard said start and stop` pulses, a synchronous multiplex transmitter, an automatic tape transmitter arranged to receive said tape and under 4control of said multiplex transmitter, a synchronous multiplex receiver, and means connected to said receiver for reinserting startstop pulses into said multiple unit code signals.

3. Printing telegraph apparatus having, in

combination, printer mechanism for transmitting multiple unit code signals having start and stop pulses, a reperforator unit for receiving said multiple unit code signals, `said reperforator being arranged to record the printer signals on tape and to dischard said start and stop,pulses, a synchronous multiplex transmitter, an auto- 'matic tape transmitter arranged to receive said tape and under control of said multiplex transmitter, a synchronous multiplex receiver for receiving the signals transmitted by said multiplex transmitter, a reperforator connected to said rean automatic tape transmitter arranged to receive said tape, and a special distributor connected to said automatic transmitter for reinserting start-stop pulses into said received signals.

4. Printing telegraph apparatus having, in combination, printermechanism for transmitting multiple unit code signals having start and stop pulses, a storing device for discarding start-stop pulses, said storing device being arranged tov record the printer signals on tape and to discard said start and stop pulses, a synchronous multiplex transmitter, an` automatic tape transmitter arranged to freceive said tape and under control of said multiplex transmitter, a synchronous multiplex receiver, and .means connected to said receiver for reinserting start-stop pulses into said multiple unit code signals.

5. Printing telegraph apparatus having, in

y combination, printer mechanism for transmitmeans connected to said receiver for inserting start and stop pulses into said multiple unitgcode i CERTIFICATE OF CORRECTION.

Patent No.'l 1,944,565."

e 1 RICHARD F. MA'1YHES.4 l

January 23, 1934.

It is herehy certified that erro-r appears in y the `printed specificati-on of" the above numbered patent requiring correction as follfowIs: Page 3, line 74',

fer. "M2" read M5; page 4, lineJ 13.6, for "start-loop" read start-step; Aandl Vpage 5, line 106, claim 5, for "dsqhard" read. discard; and that the said Letters Patent should be read with these corrections therein that the saline may conform to; the rev-oord of the case in the Patent Office.

Signed am; sealed this 14th day of July, A. D. 1936.

Henry Van Arsdale (eal) Actingv Commissioner er" Patents.

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