US1870989A - Electrical transmission of messages - Google Patents

Description

Aug. 9, 1932. B. E. ELDRED ELECTRICAL TRANSMISSION OF MESSAGES Filed Sept. 28, 1929 3 Sheets-Sheet 1 NVENTOR /Byra/1 E. E/dred BY fir TTORNEY Aug 9, 1932. B. E. ELDRED ELECTRICAL TRANSMISSION OF MESSAGES Filed Sept. 28, 1929 3 Sheets-Sheet 2 "2522? Eldrea Aug, 9, 1932. B. E. ELDRED ELECTRICAL TRANSMISSION OF MESSAGES Filed Sept. 28, 1929 3 Sheets-Sheet 3 HIIIIIIIII:

ELEcTRIc TVHEWIPIII'R Tram gm A RNEYI Patented Aug. 9, 1932 PATE T-enact:

mmon a, 21.1mm), or new i631. H. Y.'

v ummcanmmsmssron or uzssaens Application fled September 2 8, 1929. Serial No. 385,822.

marks and symbols of the usual keyboard This invention relates to the transmission of messages by wire, radio or other electrical means of communication.

One object of the invention is to produce a message in typewritten form such that it can be readily read and yet will have different light controlling power, such as translucency or reflection property, for each dissimilar character of the message and the same light controlling power f, or each similar character. Another object is to convert the typed message, thus arranged, into electrical 1mpulscs for transmission to another point. Another object of the invention is to produce light flashes from the electrical impulses previously referred toand then record said light flashes on ai'relatively moving light sensitive film or other medium, or light sensitive reflecting surface if the reflecting properties instead of the translucent propertiesare to be used. I

Another object is to produce electrical impulses at a transmitting station by controlling light by means of the record made from the light sensitive film or reflecting strip and directing this light onto a photoelectric cell or similar means to create electrical impulses proportional to the flashes of light produced by such control and then to transmit such electrical impulses to another point.

Another object of the invention is to receive electrical impulses with intensities proportional to the light controlling power of each individual letter, punctuation or spacing character of the original recorded message and then to cause each impulse to impress its corresponding character on a sheet or equivalent recording means. c

Another object is to convert the received impulses into electrical light flashes proportional in intensity to the intensity of said impulses and then record said flashes on a light sensitive medium.

Another object is to convert the lastjmenti'oned photographic record into electrical impulses proportional to the intensity of the light flashes and then' causing said impulses to record the letters, figures, punctuation corresponding to such intensity.

Other objects will appear in thefollowing specification, reference. being had to the drawings in which:,

Fig. 1 is a diagrammatic illustration of the method of carrying out the recording of the message in accordance with the invention. Fig. 2 is an illustration of the transmitting part of the invention.

Figure 3 illustrates the receiving part of the transmitted message.

Fig. 4 is a diagrammatic illustration of a section of a film record of my invention.

Fig. 5 is a viewv of part of the alphabet showin v the characters with difierent degrees o shading.

Fi 6 is a view of part of the alphabet with varia le cross hatchin on the characters.

Fig. 7 is a modifie the letter after the message has been transmitted by means of the characters of Fi .6.

Fig. 8 is a further modified form w ere photoelectric cells are substituted for the mechanical contact arrangement of Fig. 3.

Fig. 9 is a diagrammatic illustration of a portion of the film at the receiving end when letters with diflerent cross hatching as in Fig. 6 are used at the transmitting end.

It is the resent practice in transmitting messages eit er by radio or by wire to send the message either by means of Morse code, by facsimile methods or by actually operating typewriter keys at the receiving point by electrical currents created directly by the hi'mself, cannot read the message thus prepared to determine whether or not a mistake has been made; Also in the'Morse code system a series of electrical impulses must be form for reprinting.

'tions; the usual 0 cc help,- and the sender transmitted for each character of the message which increases the time of transmission. The message alsocan be read by both the transmitting OlllCC and the receiving office and is not, strictly speaking, confidential.

In facsimile transmission electrical impulses are created by light beams caused to scan or analyze a'mcssage typed on a sheet until the entire sheet has been scanned. This requires a great deal of time, relatively speaking, and the electrical impulses sent out to the distant receiving point are of great number, which greatly slows down the transmission and reception of the message.

In the operation of electric typewriters at a distance such as used in stocktickers, and other similar devices, the speed of transmission is slow because it is limited to speed of operation of the typewriter directly connected to the transmission link. The transmission link cannot be used to full efficiency when coupled directly to slow moving apparatus. Also messages received in this way are not strictly confidential as the person receiving the message, of course, can read it.

There are various other objections to the existing methods of transmitting and receiving messages and other communications and certain of these will be apparent by referring to the advantages of my invention over known systems.

In accordance with my invention I arrange the type on a typewriter, printing machine or similar device so that the impression or record made by the letters of the alphabet, numerals, symbols, punctuation marks and spaces will have different light controlling properties either in respect to translucency or in respect to reflection.

Speaking entirely by way of example, a square or other shaped space of a record on which the letter A is impressed would permit a given quantity of light Z to pass therethrough or be reflected therefrom, as the case may be. The letter 13 could be arranged to pass a quantity of light equal to (L). The letter C would pass the light k l, the letter D, lc l, etc. It is not absolutely necessary to use numerals, punctuation marks or to distinguish between capitals and small letters, 1n messages, as will be seen by noting the prac tice in the transmission of present day telegraph messages. The numerals and punctuation markscould be spelled out and all letters could be capitals, if desired, but by my system I can arrange all of these so that they would be made with different light controlling powers either by variations in translucency or in reflection properties.

The shape of the type causing the typing through carbon ribbons or by means of inked surfaces or by other means could be arranged so that the impressions would produce the variation in translucency or reflection properties while still preserving the readable nature of the characters thus made. In some cases, if desired, the light controlling power of the characters might be obtained by using substantially the present shape of type with bars or frames of black or light impeding surfaces arranged next to the letter or other character.

WVhen a message is made by a typewriter or other typing or printing machine as ust de scribed, it may be readily interpreted by the stenographer as it is being typed or otherwise made. When a mistake is made in the typed message the stenographer can immediately note the mistake and correct it in the usual way. Carbon copies of the message to be transmitted also may be made and can be kept in the files for permanent record, which copies may be read by any clerk in the ofiice who can read the language in which it was typed. The message thus typed with varying degrees of light controlling power for each character of the message may be transmitted to and re ceived at other points by the method which will now'be described in greater detail.

Light from any source-such as lamp 1, is condensed by corrected lens 2 on to the typed sheet 8 through a member 4 having an appropriate slit therein with which an appropriate rotating shutter 3 may be used. In practice the slit member would be preferably arranged close to the typed sheet, but for purposes of illustration it is shown spaced therefrom. The light coming through the slit would be projected on the area of the paper or other material receiving the impression of, say, the letter A. The light passing through this space would be impeded by the opaqueness caused by the letter itself. This character might be entirely opaque or only relatively so. The light that proceeds through the space allotted to this letter A would impinge on the cathode of a photoelectric cell 7. This would cause in a well known way the passing of electrons from the cathode to the anode. The photoelectric cell would be connected to the usual vacuum tube amplifier 7, a detail description of which is not necessary for the understanding of this invention. The amplified impulses would pass through a coil 8 controlling a mirror 9 which would reflect varying quantities of light from a light source 10 through a lens 11 and slot 11 and on to a light sensitive film 12, caused to move at the proper speed by well known means such as are used in talking motion-pictures and other sound recording apparatus. This flash of light produced by the movement of the mirror would produce, for example, when the film is developed, a pulse such as is shown at A of Fig. 4. This is the socalled variable area type of record more fully described in my copending application serial No. 395,820, filed Sept. 28, 1929, sound records and method of making the same. The amplifier and the oscillating mirror may be constructed in any way, for example, along the lines disclosed in that a plication. The slot is intended to be optica ly reduced, as described in my Patent 1,665,811, January 11, 1928. v When the'letter A has thus been recorded on the film 12 the sheet 3 would be stepped to one side by any typewriter mechanism. The typewriter mechanism is not shown as it may be of any well known construction. Arrows have been used instead to indicate thatthe sheet passes back and forth and is fed verticall This brings the next adjacent letter of the message in front of the slot 4. If this were the letter N of the word and a predetermined quantity of light would pass through the space allotted to the letter N and in the manner already described a record would be made on film 12 that would, after development, look tor example, as indicated at N in Fig. 4. The sheet 3 would then he stepped further to one sideuntil letter D of Fthe word and for example, passed under the light spot produced by slot member '4. By the means alread described a record of this character would be made on film 12 that might, for example, appearas at D of Fig. 4 when the film is develo ed. The shape of the variable area reco for letters of the word and has been assumed by way of ex- 3 ample only. An shape desired may be pre-' determined for t ese letters. The only distinction is that they should be difierent from each other. Also, variable density recordingmay be made as described in my copending application referred to herein. When the end of the word and has been reached, for example, the area allotted to the space between this word and the next word would pass a certain quantity of light when w this area is passed under the light spot caused by slot member 4. Preferably this area ass1gned to thespacing character would have the translucency of the sheet of paper on which the message is typed or printed, that is,

46 it would have greater light transmitting or controlling power than the letter or punctuation characters. This would produce a record such as 14 in Fig. 4, the top portion being out 01f in this figure as this Fig. 4 gives only a section of the record assumed in this case.

This record in Fig. 4 also may be a positive or negative after development and the white and lackspaces are made in this figure merely to show the type of records that could 55 be made in the method disclosed without reference to the positive or negative nature of the record. Words of the line being recorded would be recorded in exactly the same way as the word .and and the words occurring to thereafter in this line would also be recorded in this way. When the end of the line is reached appropriate and well known mechanism would come into play to move upwardly suificiently to bring the next line of the message into position. Also at this time the sheet 3 would have been moved to bring the first part of the line under the spot of hght. In this w'ay'the entire pa e of the-message is brought before the spot 0% light in succession and a recordmadeon the moving film 12. All of these steps in the method would have taken place rapidly by appropriate mechamsm.

To preserve messa es in secrecy the film record 12 may be ma e in apparatus located and controlled-by the oflice or'person desiring to transmit the message. The film would then be sent to the transmitting company for transmission to the desired distant point, as will "now be described. 'The development of the fihn could behandledeither by the cus tomer or the transmitting company or by anyone else.

The transmission system is more or less dia grammatically illustrated in Fig. 2. The film'12 of Fig. 1 is placed on appropriate reels of suitable apparatus such as is well known in the motion picture art and is passed rapidly in front of a'source of light 15, The light passes through lens 16 and through a slot 17 on to film 12 to throw a spot of light successively on to the recorded impulses such'as A, N, D and 14, for example, of Fig. 4. A varying quantity of light will pass through this 4 record and onto the cathode of photoelectric cell 18. -An electrical im ulse will then pass from photoelectric cel corresponding to the amou of light passing through the film allotted to record A of Fi 4. This preferably would be amplifiekf by vacuum tube amplifier 19 or otheramplifier and assed over the radio or wire link 20, wire eing shown by way of example,

and again amplified at the receiving end if desired by suitable amplifier 21, in the output of'which would be a mirror or other light controlling device 22 by means of suitable coil or magnet 23. The mirrors 9 and 22 may be of any construction, for example, such vas shown in patent to Hoxie, #1,598,377, April 21, 1926. As shown, the mirror would control the light coming from light source 24 to produce reflecting beams or flashes of light through lens 25 and slot 25 and condensed on to a light sensitive film 26 moved at appropriate speed past the condensed light spot by appropriate reels and other mechanism.

As soon as the letter A of. Fig. 4 has been recorded letter N will instantly ollow thereafter on the film 26, the letter I) immediately will be recorded thereafter and then the space 14 will be recorded. In this way record 26.

will be a duplicate at the distant end of record. 12.

By the process just described the radio or wire transmission 20 will be tied up only a veryshort time, while the record or film 12 is being rapidly transmitted and the record 26 is being made at the receiving end.. In prior processes where Morse. code, facsimile apparatus, and ordinary stock ticker typewriter mechanism is being opera-ted at the transmitting and receiving end, the transmlssion is slow due to the inherent operationof the relatively slow moving apparatus. W'ith my method as just described the apparatus of moving films 12 and 26 is operated at very high speed and the transmission line or radio link is tied up only for a very short time to transmit the message in the manner described.

By my processa wire line or a radio link is capable of transmitting enormously greater described. The film 26 of Fig. 2 after development will be put on appropriate reels and other apparatus well known in the talking motion picture and film phonograph art. Light from any source 27 will be condensed by lens 28 and slot member 29 on to film 26. The light passing through this film will be projected on to the cathode 30 of the photoelectric cell in well known ways. Continuing the explanation with the word and, as before, by way of example, the light condensed on the area allotted to the letter A will have a certain value due to the translucency of this area. This quantity of light will produce a definite current flow into the input circuit of the vacuum tube or other amplifier 31 by electron flow between the cathode 30 and anode 32, as described more in particular in my above mentioned application. This electric current after amplification will pass into the output circuit containing any electromotive arrangement such as any well known dead beat galvanometer arrangement. I have illustrated in moreor less diagrammatic form this galvanometer arrangement in Fig. 3. The output from the amplifier 31 passes through line 33 to hairspring 34 to coil 35 and out through a similar hair spring, hidden from View in this figure, and thence back through line 36. This produces electromagnetic force along the axis of coil with the north pole in the direction of the arm 37 which is attached to and rotates with coil 35. The interaction between these magnetic lines of force and those produced by the pole pieces whose polarity is indicated by N and S causes the coil and arm 37 to rotate clockwise. Let it be supposed that a record for the letter A is on the film 26 where the light beam is centered. The amount of current produced by the photoelectric cell will be suificient to swing the galvanometer arm to'some position, say contact 38. This will cause current to flow from battery 39 through strip 40 across contact brushes and connecting strip, generally indicated by 41, to contact strip 38 through the connected wire in cable 42 to the electric typewriter 43'. Electric typethe sheet in the electric typewriter and step the sheet forward for the next letter.

As the film 26 moves to the next character N in the word and assumed to be transmitted, a different quantity of light will pass into the photoelectric cell and a diiferent value of current will move the armature arm 37 to some other position on the series of contacts. Merely by way of example, let it be assumed to move the contact point to contact 44. This would energize coil 35 and close the contact leading to another magnet or control member at the keyboard of the typewriter 48. This would cause the electric typewriter to type the letter N on the sheet of paper. The film 26 would then move to the space alloted to the letter D and arm 37 would move the contact in the way described and cause energization of another electromagnet which would cause the letter D to be typed on the sheet of paper in the electric typewriter. lVhen the area alloted to the space after the latter N comes under the spot of light passing through the slot member 29 a greater quantity of light will be thrown into photocell 30. In the way described this will cause a spacingmagnet on electric typewriter 43 to move the shiftmechanism on the typewriter to cause a space between letter N already typed on the sheet of paper and the next letter will be typed thereon when 26 moves to the next. letter or character, whatever it may be.

In the way described, the message appearing on film 26 will be typed out on the sheet of paper in the typewriter 43. At the end of the line the typewriter carriage will automatically reset for another line or a separate character having a definite light value may be assigned to it for operation of a control for turning the platen roller and shifting the carriage. After the entire message including the typed signature, date, etc. has been typed on this sheet of paper it may be removed and delivered to the addressee whose name would app-ear at the head of the message having previously been typed on the original type script or record of Fig. 1.

The apparatus diagramn'iatically illustrated in Fig. 3 could be located in the oflices of customers, particularly where the amount of correspondence received by this system is sufiiciently large to warrant the acquiring of such apparatus. In that case the operators in the receiving oflice of the communication company would be unable to read the message on film 26. 1 l I Also to render the message confidential without necessitating customers having the 5 transcribing a paratus of Fig. 3, such apparatus when ocated in the receivlng oflice of the communication company may be arranged so that the sheet of paper issuing y from typewriter 43 and containing the typed in message is automatically folded and slid mto an envelo e and sealed by appropriate ma; chinery not shown) with the name and I address of the customer appearing through the usual transparent Window of envelopes now on the market. This could be delivered to the customer 'withoutanyone knowing the contents. i

In making the original typed script record in holder 3 of Fig. 1 the impressions could so be made if desired in the form of squares or other shapes having varying degrees oftrans' lucency. Such a type script would, of course, be illegible and would be entirely confidentlal. M When transmitted and received by the apparatus of Figs. 2 and 3, as alread described, the message in legible type woul issue from the typewriter &3. This is not so desirable as the system just described because the typist making the original type script 1n the office of the sender would not be able to read the type script and make corrections for errors except by being skilled in the reading of such a code. For this reason I prefer have the original type script appearin' ID holder 3 ofFig. 1 to appear in readable orm as first described and secrecy can be maintained especially. in large offices of customers by having the apparatus of Fig. 1 located in f such oflices. The characters themselves and 40 the squares that are allotted to them may be variously shaded, as illustrated in Flg. 5,

so that each'one will pass or reflect a, difl'er-' ent amount of light from the others. The i typed message could also be maintained con fidential by enclosing the sheet of type script, such as would be placed in the holder 3, in a fiat envelope, which could be automatically opened by machinery at the ofiice of the transmitting company and the sheet fed into the .holder 3 automatically and again sealed when it is recorded on film 26. The sealed letter after transmission could then be destroyed, returned to the sender or filed awa in sealed condition for future use in the o ces of the communication company subject only to be opened b appropriate rulesof that company, sucl i as by order of a court.

While I have described by way of example, the use of films for records 12 and. 26, it will be understood that tapes having reflecting surface such as' glossy paper, may have a sensitized surface to receive the photographic record and the light directed into the photoelectric cells by reflection from the 1 record. This power of directing light into the photoelectric 0 11s, whether by translucency or reflection property of thefihns or tapes maybe called for convenience,'the light controlling power of the characters employed to convey the message.

While I have described the apparatus of Fig. 1 as being associated with a telephone or telegraph wire line, it will be apparent that the apparatus can function in exactly thesame way by associating it with a'radio transmitting and receiving system. It also will be apparent that the telephone or telegraph line of Fig. 2- can carry either socalled audio currents or carry or guide radio frequency currents such as is used intranscontinnetal carrier current systems atthe present time.

I have described the preferred system as embodying all the steps illustrated in Figs.

1-, 2 and 3 but some of the advantages of my 86 invention can be obtained by making the type script such as is on the sheet in the holder 3 of Fig. 1 and sendingthecurrents coming through the amplifier ,8 that figure directly into the transmission system of Fi 2. In such a simplified system the electrical typewriter apparatus of Fig. 3 could be connected directly to the amplifier 21. In this siniplified system films 12 and 26 would be eliminated. This'is not the preferred 5 form, however, as the wire line or radio link would be tied up for a longer'time due to the inability of the typing apparatus, associated with sheet 3 at the transmitting station and that associated with the galvanometer in the receiving station, to function as fast as the apparatus that moves films-12 and 26. However, this abbreviated form of apparatus would have advantages and itis one form of my invention. I My invention is therefore directed to the use of all'or any part of the novel features of the entire system. a

In making the photographic records on films 12 and 26 I may use either thespeed films or the slower films of .fine grain emulsion such as referred to in my copending application Serial No. 395,820 filed Sept. 28,

Instead of variable area records I also may use variable density records well u known in the art and referred to in that copending application. I also may use either the vibrating mirror type of light control, or the neon or other lamp type. both of which are disclosed in no my copending ap 'lication. However, my invention is not llmited to any particular type of control and the one disclosed in particular herein is suflicient to set forth the principles of thein'vention. Instead of using a type script depending upon quantity of light'for sending the message, I-may use alternatively line impressions on the type script which have different 213,

frequency characteristics, that is, I may make the type so that impressions will be caused on the type script having, say L lines for the letter A. It. for the letter B, k for the letter C, etc. I have shown a portion of the alphabet in Fig. 6 where the letters have different cross hatching to give the desired frequency of interruption of the light. The number of cross hatching lines of course are indicative only. 1 may have the cross hatching of the respective letters differ by any amount. These lines could extend across the space allotted to the letters with transluccnt portions in between like the hatching on a drawing. The type script having these impressions made. iip of the different number of lines for each character could then be scanned by beams of light passing rapidly across the lines of the type script in rapid succession. The light passing through the space allotted to each character would be interrupted by the hatching and cause a definite frequency of interruption of the light depending upon the speed of movement of the paper, but one frequency would be exactly proportional to the number of lines on each impression. That is, the light intcrrupted by the impression for the character A would have a frequency of say, hf, for the letter B would have a frequency of 71: 7, for the letter a frequency of lc f and so on. The method of scanning, such as in facsimile and television systems is well known in the art and apparatus for doing this need not be described in detail. The light spot should scan one line of light in one sweep across the page instead of in a large number of sweeps as in facsimile and television work. The light of definite frequency passing through each character when sent into a photoelectric cell relatively moved with the spot of light would produce electric impulses of the frequencies corresponding to the frequency of interruption of the light by the lines of each character. These elec tric impulses of definite frequency for each character could be used to produce a record such as 12 having similar frequency characteristics, or these impulses if desired could he sent directly over the wire or radio link. If film record 12 is made with the frequencies as I prefer, the movement of the film in th apparatus of Fig. 2 would produce definite frequencies to be relayed over the radio or wire link.

In this modification each character would generate a current of a number of pulses, whereas in the method described in connection with Fig. 1 each character generates one pulse only.

Fig. 7 diagrammatically illustrates the electrical system for retyping the message from the film record made at the receiving end when the characters have different frequeney of light interruption as in Fig. 6. The circuits for only a portion of the char- -ruption of the letter A.

acters are used but the others would be similar. In this figure the light from the lamp 27 would pass through the slotted member 29, lens 28, film 26, on to the sensitive electrode 30 of the photoelectric cell through the amplifier 45. The output of this amplifier is connected to bus wires 46, 47, and would be impressed between the filament and grid of all of the vacuum tube relays 48, 49, 50, etc. The plate circuit output of all these relays feed into their corresponding vacuum tubes 51, 52, 53, etc. These are all tuned differently, for example, the grid circuit of tube 51 would be tuned to the frequency of inter- The circuits of 52 and 53 would'be tuned to the frequency of letters I) and C, etc. Since We have assumed that the portion of the. film 26 that at this instant is receiving the light beam corresponding to the letter A, the tuning of the circuit 51 of this frequency will buildup a very large current in the circuit, whereas the current in the other circuits will not be built up because the tuning of these circuits is different. Therefore the current will be greatly increased when it passes through vacuum tube 1. The output of vacuum tube. 51 will be connected to wires leading to the magnet in the electric typewriter 43 and the letter A will be typed on the sheet therein. In this way the. movement of the filament 26 will cause the corresponding letter to be typed in the sheet 43. I have illustrated only one tuned vacuum tube stage but I may use any number of such tuned stages in cascade to select and build up the current.

The record made on film 26 at the receiving end by the system of Fig 2 when characters of different frequency, as in Fig. 6, are being used, would appear different from the film shown in Fig. 4. I have schematically illustrated the record on film 26 in this case in Fig. 9. In this figure the letter A would have a certain number of oscillations. the letter B a different number, the letter C a still different number, and so on.

As another alternative method. at the receiving station I may use a sensitive dead heat galvanometer with an attached mirror adapted to take a. definite position determined by the intensity of the current received over the radio or wire link, as first described. A series of photoelectric cells corresponding in number to the number of the characters employed in the system would be located in position. to receive a beam of light as the mirror takes its definite positions in accordance with the strength of the current received. The retyping is preferably made from a record like Fig. 4 so as to permit the radio or wire transmission link to be used in continuous operation at high speed for making the film records at the receiving station. I have shown diagrammatically a system in Fig. 8 for retyping in this way the succession and return to sweep across the same message recorded at the receiving end. In this system similarparts have been given similar reference characters and the galvanometer has been schematically shown. It may be similar in construction to the one shown in Fig. 3 except that it has a mirror 5 that is rotated by the rotatable coil 35. When the letter A is being retyped from filament 26 light from lamp would be reflected from the mirror 54 to photoelectric cell 56. Cur-f rent from this photoelectric cell would be amplified at 57 and the output passed into wires in the cable 42 to the typewriter 43 where the letter A would be typed in a way already described. The other letters of the alphabet would be similarly retyped, and the operation need not be further described.

' In the system of Fig. 8 the record on the film 26 would be like that shown in Fig. 4..

The galvanometers in Figs. 3 and 8 would be of dead beat form. It is the practice at the present time .to make such galvano= meters dead heat by placing an appropriate resistance 58 across the terminal wires of the coil 35. Such a resistance prevents the armature from oscillating because an oscillating armature generates currents from the mechanical motion. These currents are damped out by the resistance 54 which therefore acts as an electrodynamic brake. Consequently the mirror moves quickly to the position corresponding to the strength of the current of the character being typed and remains at this osition without oscillating. The galvanometer and the damping resistance are old and well known in the art and have been illustrated digrammatically and described in order to make the operation of the system It is, of course, immaterial, as far as the spirit of the invention is concerned, whether the message is typed on a so-called typewriter, or by means of a printing press or other apparatus.

The type script paper shown in'Fig. 1 may either be arranged with the face of the sheet toward the light source or away therefrom,

that is the type script could be made either to appear as a positive or negative in respect to the source of light. In either case the mechanism of the apparatus would be arranged so that the letter would be fed relatively to the spot of light in the proper direction.

My invention broadly distinguishes from facsimile and television systems in that each letter or other character is scanned or analyzed completely byv one sweep of the light beams before proceeding to the next char acter. In the other systems the light beams sweep across the tops'of the characters in characters in series for another increment of area. It thus takes a relatively large number of sweeps of the light to compute the scanning of one line of the typed letter. In

my invention one sweep of the light across the page completely scans one line, each let-w ter or other character bein completely scanned before thelight" proce s to the next.

In some cases itmay be desirable to use a rotating shutter as in motion picture apparatus, to pass the light only while the type characters or space is stationary.

Paper or sheets of other material of special translucency may be used for making the type script record if preferred, but typewriter paper now on the market will sufljce.

Other modifications may be made without departingfrom the spirit of the invention.

Having described my invention, what I- claim is:

.1. The method of transmitting a message which consists in making a lighteontrolling record of said message, passing light through said record to produce flashes, producing electrical impulses having intensities proportional to said flashes, and producing impulses at another point proportional thereto.

2. The method of transmitting a message which consists inmaking a light controlling record of said messa e, passin li ht throu h g g a g said record to produce flashes, producing electrical impulses having intensities proportional to said flashes, producing at another point impulses proportional thereto, and pro- .5

point impulses proportional to the first mentioned impulses, producing a record of said impulses and converting said. second mentioned record into directly readable language.

4. The method of transmitting a message which consists in making a record of the letter, punctuation, spacing or other characters thereof with different light controlling power for each dissim lar character and the same light controlling power for each similar character, producing light flashes by said characters, producing electrical impulses propor-v tional to the intensity of said flashes, produc ng impulses at another point proportional to the first mentioned impulses and re-recordingsai d characters by means of said impulses.

I 5. The method of transmitting a message which consists 1n making a record of the latter, punctuation, spacing and other cha-racters thereof with different light controlling powerfor each dissimilar character and the same light controlling power foreach similar character, producing lightflashes by said,

characters. producing electrical impulses proportional to the intensity of said flashes, producing at another. point impulses propor- I om CU tional to the first mentioned pulses and rerecording said characters by means of said impulses.

(3. The method of communicating messages which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses by said light rays and producing at another point electrical impulses proportional to the first mentioned pulses.

7. The method of communicating messages which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses by said light rays, producing at another point electrical impulses proportional to the first mentioned impulses and retyping the message from said impulses.

8. The method which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses by said light rays, and producing light flashes proportional to said impulses.

9. The method which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses from said light rays, producing light flashes proportional to said impulses and making a record of said flashes on a light sensitive medium;

10. The method which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses from said light rays, producing'light flashes proportional to said impulses, making a record of said flashes on a light sensitive medium, and producing electrical impulses proportional to said flashes.

11. The method which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses from said light rays, producing light flashes proportional to said impulses, making a record of said flashes on a light sensitive me dium, producing electrical impulses proportional to said flashes, and producing at another point electrical impulses proportional to the second mentioned impulse.

12. The method which consists in typing a message, completely scanning by light rays each letter character thereof before proceedingto the next, producing electrical impulses from said light rays, producing light flashes proportional to said impulses, making a record of said flashes on a light sensitive. medium, producing electrical impulses proportional to said flashes, producing at another point electrical impulses proportional to the" second mentioned impulse, and producing light flashes proportional to said last mentioned impulses.

13. The method which consists in typing a message, completely scanning by light rays each letter character thereof before roceeding to the next, producing electrical impulses from said light rays, producing light flashes proportional to said impulses, making a record of said flashes on a light sensitive medium, producing electrical impulses proportional to said flashes, producing at another point electrical impulses proportional to the second mentioned impulse, producing light flashes proportional to said last mentioned impulses, and then recording said flashes in a light sensitive medium.

14. The method which consists in typing a message, completely scanning by light rays each letter character thereof before proceeding to the next, producing electrical impulses from said light rays, producing light flashes proportional to said impulses, making 2. record of said flashes on a light sensitive medium, producing electrical impulses proportional to said flashes, producing at another point electrical impulses proportional to the second'mentioned impulse, producing light flashes proportional to said last mentioned impulses, then recording said flashes in a light sensitive medium, and retyping said message by means of said last mentioned flashes. I

15. The method of communication which consists in typing a message, interrupting light by the typed character, passing the interrupted light onto a photoelectric element to produce a varying current, producing a variable light by said current and making a record from said variable light.

16. The method of communication which consists in modulating an electrical current in accordance with a plurality of messages to be transmitted, producing light from said current, making a photographic record from said light, modulating an electrical current from said record and transmitting said current.

17 The method of communication which consists in modulating an electrical current in accordance with a plurality of messages to be transmitted, producing light from said current, making a photographic record-from said light, modulating an electrical current from said record, transmitting said current, and making another photographic record at the receiving end therefrom.

18. The method of communication which consists in modulating an electrical current in accordance with a plurality of messages to be transmitted, producing light from said current, making a photographic record from said, light, modulating an electrical current from said record, transmitting said current, making another photographic record at the receiving end therefrom and making the llu original form of said messages from said last mentioned record.

19. The step in the method of communicating messages which consists in transmit- 5, ting light by each entire character in said message to form a single pulse of current by each character and making a photographic record of said pulses.

20. The step in the method of communi- 10 cation which consists in typing a message, passing each typed character in front of a light source, forming a single pulse of current from the light that is transmitted by the whole of each character and making a 15 record of the said pulses.

21. The method of communicating messages which consists in transmitting light by each entire character in said message to form a single pulse of current for each of 20 said characters, transmitting all said pulses I and converting the pulses at the receiving end into the original characters of the message.

22. The method of communication which 85 consists in typing a messa e, passing each typed character in front 0 a light source, forming a single pulse of current from the light that is transmitted by the whole of each character, making a record of the said 8 pulses, converting said record into current pulses, transmitting said pulses to a receiving station making at the receiving station a record 0 the current pulses and forming each on final characters from the correspond- 85 ing pulse.

11 testimony whereof, I have signed my name to this specification this 27 day of September, 1929.

, BYRON E. ELDRED.

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