US3401385A

US3401385A - Serial pulse continuous message indicator system

Info

Publication number: US3401385A
Application number: US408478A
Authority: US
Inventors: Jaffe David Lawrence
Original assignee: Polarad Electronics Corp
Current assignee: Polarad Electronics Corp
Priority date: 1964-11-03
Filing date: 1964-11-03
Publication date: 1968-09-10
Anticipated expiration: 1985-09-10

Description

Sept. 10, 1968 D. 1.. JAFFE 3,401,385

SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM Filed Nov. 3, 1964 15 Sheets-Sheet 1 4 (:1 'li'fi II I! DC) 0 0 013C: 0 [Hrs-cw y U LII J ci-fi" VISIBLE CHARACTERS CHARACTERS J 1 TO FOLLOW APPARENT MOTION WORD UNIT 30-2 WORD UNIT 30-! Isa-l2] 35- I 3540] 35-9 [35-8 |3s-1 35-6 1 35-5 35-4 1 35-: 35-2 |-5s-| A A M k k k k 52-2 52-1 1 UNIT 30-l SWITCH UNIT 30-2 SWITCH I \4s-2 (50-2 (48-2 45-: {SO-l [AB-l COMM- M Mo Y COMM- M M LATCH UTATOR (RSIQEI a) .MoTOR LATCH UTATOR (E I JR R MOTOR E 47-21 I L47-| 1 44-2 54) 49-2 44-l I LATCH MOTOR LATCH MOTOR IRELAY AMPL'F'ER AMP. RELAY v AMP.

TRANSFER 533 START 4Q) 42 PULSES ATA ND D swfc A SYNC. INFQ. PULSES SOURCE SEPARATOR SYNC PULSES 3 INVENTOR. 0. LAWRENCE JAFFE ATTORNEYS D. L. JAFFE Sept. 10, 1968 SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM 15 Sheets-Sheet 2 Filed Nov. 5, 1964 INVENTOR 0. LAWRENCE JAFFE BY @0114 f 4901 vdE ATTORNEYS Sept. 10, 1968 I D. L. JAFFE 3,401,385

SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM Filed Nov. 5, 1964 15 Sheets-Sheet :3

I SYNCH soI START/ INVENTOR.

, F I G, 5 BY D. vLAWRENCE JAFFE ATTORNEYS D. L. JAFFE Sept. 10, 1968 SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM 15 Sheets-Sheet 5 Filed Nov. 5, 1964 356 56228 mow Om mwooma N NE INVENTOR. D. LAWRENCE JAFFE ATTORNEYS D. L. JAFFE Sept. 10, 1968 SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM 15 Sheets-Sheet 6 Filed NOV. 3, 1964 INVENTOR. D. LAWRENCE JAFFE ATTORNEYS Ow Pm mw wail: OF mwz] "E095.

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D. L. JAFFE SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM SYNC - a-ln- NEG. START PULSES FOR NEXT DRUM UNIT 4 OPEN AFTER 15 Sheets-Sheet 10 NEG. INFO. PULSES FOR NEXT DRUM INVENTOR.

SENSE AND ERASE D. LAWRENCE JAFFE ATTORNEYS 493 I94 492 i 2495 Z Sept. 10, 1968 D. JAFFE 3,401,385

SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM Filed Nov. 5, 1964 15 Sheets-Sheet 11 ROTATION OF 270- IOG 270- IO8 47 [T142704 27o-|5 m 27o-|s $8 I I I I I I- I I I I I I I I I I I I I 1 $1 276 REGEN SYNC PULSE ERASE AMPLIFIER (RESET) s12 AND TRANSFER 498 FOUR/ TRANSFER 27040?) 276 ERASE 270-ll8l IIIJQIIIIIIIIIIIIIIIII RESET SYNC PULSES SERIAL TO F'FTEEN PARALLEL REGEN. AMPL. CONVERTER 497 (FIG. IOA) I ZIO FIFTEEN REGEN. AMPL. 497

INVENTOR. D. LAWRENCE JAFFE TO NEXT DRUM BY ATTORNEYS D. L. JAFFE Sept. 10, 1968 SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM 15 Sheets-Sheet 12 Filed Nov. 5, 1964 I N VENTOR.

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SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM Sept. 10, 1968 15 Sheets-Sheet 14 Filed Nov. 5, 1964 START RELAY ROTATION TO MODU LE T0 MODULE READER 5 STATION WRITE sso TRANSFER MEMORY READER BANK STATION ONE TO moouua I 35-1 FIVE Q READER STATION TWO 222 READER STATION E THREE TO moouu-z TO MODULE 35-2 FIG. IOC

INVENTOR. D. LAWRENCE JAFFE BY g fl fl ATTORNEYS United States Patent 3,401,385 SERIAL PULSE CONTINUOUS MESSAGE INDICATOR SYSTEM David Lawrence Jatie, Great Neck, N.Y., assignor to Polarad Electronics Corporation, Long Island City, N.Y., a corporation of New York Filed Nov. 3, 1964, Ser. No. 408,478 13 Claims. (Cl. 340339) ABSTRACT OF THE DISCLOSURE A message display system in which serially occurring data pulses control apparatus actuate alphanumeric devices to produce a continually moving, parade type display on the alphanumeric display devices.

This invention relates to a message display system and more particularly to a system for producing a message of alphanumeric characters in a parade type display in response to serially occurring information signals.

Many applications exist Where it is desired to produce a moving message display. One familiar application is in a sign of the type Where a number of characters move across the face of the sign to display information such as news, weather, etc.

The present invention is directed to a message or data indictor display system capable of continuously displaying visual information in a moving pattern. In accordance with the invention the data corresponding to the message to be displayed is produced by a suitable source in the form of serially occurring .pulses. These are conveyed to the display unit of the system via a two wire telephone or telegraph line, a radio link, or any other suitable communication system. The display unit includes a number of alphanumeric character indicator modules arranged in a predetermined manner, for example side by side, for producing the desired moving message. These modules are controlled by the serially occurring data pulses in a predetermined manner to produce the desired moving message in a parade display.

In the preferred embodiments of the invention the alphanumeric character modules are of the electroluminescent type or other switchable luminous devices and formed by a number of segments which can be individually energized to produce a predetermined character, such as a number or letter. A storage medium receives a number of sets of serially occurring data pulses from the source and each set of the data pulses corresponds to one character to be produced on one character module. The storage medium and its associated apparatus first stores and then reads out each set of pulses in parallel to control one module. Each set is read out sequentially to produce a moving indication of the data on the character modules.

In the preferred embodiments of the invention the medium for storing the sets of serially occurring data pulses is a storage drum including a plurality of sets of glow lamps. This forms a relatively inexpensive storage device. Each set of lamps stores bits of information corresponding to one character of the message to be reproduced and each set of lamps is rotated past a number of readout stations which control the energization of a respective character module to produce a character. Rotation of the plurality of sets of lamps past all of the readout stations causes the characters to move sequentially from one indicator module to the next to produce a moving message display. In accordance with the invention an arrangement is also provided for transferring the data stored in the glow lamps of one drum to the glow lamps of another drum, thereby increasing the capacity of the system.

It is therefore an object of the present invention to provide a moving sign type of message or data display which operates from serially occurring data signals.

A further object is to provide a message or data indicator for displaying information in a moving pattern.

Another object is to provide a message or data indica tor using electroluminescent or other luminescent type character modules which are controlled by serially occurring signals to produce a sequential parade type display of a message.

Still another object is to provide a data indicator for producing a moving message in response to serially occurring data signals received over a two wire transmission line, radio link, or other type of communications system.

Other objects and advantages of the present invention will become more apparent upon reference to the following specification and annexed drawings in which:

FIGURE 1 is a plan elevational view of a word unit;

FIGURE 2 is an elevational view of one of the indicator character modules;

FIGURE 3 is a block diagram illustrating the general principles of the invention;

FIGURE 4 illustrates the types of signals generated and used in the system;

FIGURE 5 is a developed view of a portion of a drum used for generating the signals of FIGURE 4;

FIGURE 5A is a schematic Wiring diagram of the lamp assembly for the signal producing drum;

FIGURE 5B is a schematic block diagram of a portion of the signal processor;

FIGURES 6A and 6B are diagrams, partially in schematic form, of a keyboard type unit for producing the signals of FIGURE 4 by operation of the drum of FIG- URE 5;

FIGURE 7 is a diagram of the reader unit;

FIGURE 8 is a wiring digram of a portion of the glow lamp circuits and readout circuits for one of the reader drums;

FIGURES 9A, 9B and 9C are schematic diagrams of circuits for controlling the operation of the reader drum and for transferring data from one reader drum to another; and

FIGURES 10A, 10B and 10C are schematic diagrams of another embodiment of reader drum using external storage;

FIGURE 11 is a schematic block diagram of the system using the reader drum of FIGS. l0A10C; and

FIGURE 12 is a schematic diagram of a system using the drum of FIGS. IDA-10C and FIG. 11 for transferring data from one drum to another.

FIGURE 1 shows the type of moving message which is produced by the present invention. The message is formed by a number of visible characters, here illustrated by the letters POLAR of the word POLARAD. These .visible characters are part of a word unit 30 formed by six indicator character modules 35-1 35-6. Of course, the size of the word unit 30 may be increased as desired and a plurality of word units may be used.

The six indicator modules 35 of the word unit 30 are located side-by-side, as shown in FIGURE 1, to produce the moving message. Each indicator module preferably is of the alphanumeric type which is formed by a number of segmented light emitting element-s. In a preferred embodiment of the invention the segments or elements are of the electroluminescent type. Indicator modules of this general type are currently available commercially, one suitable type being sold by Sylvania Elec corresponding reference numerals 1-15. By selectively energizing several of the elements 1-15 at the same time, a predetermined pattern corresponding to letters and numerals can be formed. Throughout the remainder of the specification and in the claims the term character is used to designate letters, numerals and punctuation marks producible by the system on a character indicator module. While a fifteen element indicator module is shown, other suitable types may be used, for example, the twelve element module shown in Sinninger Patent 3,081,450. It is preferred that the segmented elements to be illuminated be of the type which can be energized through low current switches. Of course, other types of indicator modules may also be utilized, for example, those using a plurality of neon tubes, incandescent tube lamps or banks of inoandescent lamps. All of these would be arranged in a pattern on the order of that in FIGURE 2 to enable all letters and numerals to be produced.

As can be seen from FIGURE 2, any character can be formed by energizing the proper segments of an indicator module 35. For example,

elements

1, 2 3, 4, 5, 8 and 12 would be energized to produce the letter A. To produce the letter B,

elements

1, 2, 3, 4, 5, 6, 8 and 12 would be energized. Other letters and numerals are formed in a similar manner. Element 15 is for a period.

A chart can readily be prepared to show the energizetion pattern of the elements to produce the desired character. The preparation of this chart merely requires determining the outline of the desired character and listing the elements of the particular indicator module being used which must be energized to produce it. The information derived from such a chart is used to operate switching elements to control the energization of the indicator modules 35 in a word unit 30 in a manner which is de scribed in detail below.

By energizing the respective individual indicator modules 35-1 35-6 of a word unit 30 in sequence with successive characters of the message, a parade type display is produced which gives apparent motion to a message. To illustrate, consider that the first letter P of the illustrated word successively moves from indicator module 35-1 to module 35-2, etc. Each succeeding letter of the word follows behind the letter P and a message with apparent motion from right to left is produced. Of course, the indicator modules 35 remain stationary.

It should be understood that a plurality of word units 30 formed by six or more character indicator modules 35 can be arranged side by side to produce longer messages. A system utilizing two such word units 30-1 and 30-2 is shown in block diagram form in FIGURE 3. It should be understood that this system may be enlarged to use additional or larger size word units as desired. Before describing this system reference is made to FIGURE 4 which is a diagnam illustrating the types of signals used to operate the system.

As shown on line A of FIGURE 4, each character frame time, i.e., the interval during which information corresponding to a single character is produced, is divided into twenty-two periods. Each period is divided in half giving a total of forty-four half periods or spaces and each of the twenty-two periods is schematically represented on line A of FIGURE 4 by a positive going pulse appearing during the first half of each period (odd numbered space) and then the absence of a pulse during the second half of each period (even numbered space). For convenience of description, the forty-four spaces of each character frame time are numbered 1 through 44 on line A.

As shown on line B of FIGURE 4, a negative going start pulse is produced during the first half of each of the first four periods, that is in

spaces

1, 3, and 7. If desired, the series of four start pulses may be replaced by a continuous start pulse occupying the first seven spaces. The fifth through twenty-second periods, as shown on line C, each has a positive going sync pulse during the first half of each period, i.e., at the odd numbered spaces 9 to 43. This makes a total of eighteen sync pulses. The. information signals occur as negative going pulses during the second half of the fifth through twenty-second periods, that is, at the even numbered spaces 10 through 44. This is shown in line D which is a representation of the composite signal of start, sync and information pulses used to operate the system. It should be understood that the selection of the polarities and spacing assignment for the various pulses of the composite signal is optional and that any desired arrangement may be used.

In line D of FIGURE 4 information pulses corresponding to the letter A are shown so that the negative information pulses occur during the second half of the fifth, sixth, seventh, eighth, ninth, twelfth and sixteenth periods, i.e., even numbered

spaces

10, 12, 14, 16, 18, 24 and 32. Stated another Way, each negative pulse occurs at the indicator module element number of FIGURE 2 plus four and one-half periods or nine spaces. The shift of nine spaces is occasioned by the start pulses during

spaces

1, 3, 5 and 7 and the first sync pulse at space 9. It should be understood that the information signals for other characters would occur during the odd numbered spac s of the second half of periods of the composite signal corresponding to the module elements which are to be energized to produce them plus the nine space shift.

Referring again to FIGURE 3, the composite signal of line D, FIGURE 4 is produced by a suitable source 40, which will be described in detail below, and applied to a sync separator 42. Sync separator 42 separates the st-art, sync and information pulses from the composite signal of FIGURE 4. This is done quite readily by a pair of biased diodes which pass pulses above or below thereference level about which the composite signal fluctuates.

The start pulse or pulses from sync separator 42 are applied to latch relays 44-1 associated with word unit 30-1. Latch relay 44-1 operates a mechanical latch 45 which physically engages the corresponding memory drum 47 or an auxiliary portion thereof to prevent it from rotating. When relay 44-1 is energized it picks up latch 45-1 and frees the drum 47-1 for rotation by a stepping type motor 48-1.

The sync pulses from separator 42 occurring after the start pulse are applied to a respective motor amplifier 49-1 for controlling the action of the stepping motor 48-1 in a synchronized manner. The serially occurring information signals from separator 42 are applied to a commutator 50-1 in the first word unit 30-1. Commutator 501 distributes the information signals to be stored by memary drum 47-1 in a manner such that they may be read out at a later time.

Information stored on memory drum 47-1 is read out and applied through a switch 52-1 to operate indicator modules 35-1 35-6 of word unit 30-1. As will be described in greater detail below, each set of information signals corresponding to a character is read out and used to energize the elements of one of the modules 35 to visually reproduce the character. As the drum 47-1 is rotated, each set of signals corresponding to a character, is successively moved to a different readout station to control a different indicator module. The visually reproduced character therefore moves from module to module and from right to left in the system of FIGURE 3. When drum 47-1 contains six sets of signals all six modules 35-1 to 35-6 will be energized simultaneously.

The drum 47-2, commutator 50-2, and switch 52-2 operate in the same manner to control the energization of modules 35-7 35-12 of word unit 30-2. However, instead of commutator 50-2 receiving the start and information signals from sync separator 42, these are supplied from the commutator 501 by a transfer device 53 to be described later. Transfer device 53 receives serially the set of information signals previously used to energize module 35-6 and applies them through an amplifier 54 to commutator 50-2 to control the energization of module -7. This transferred set of signals moves along with the rotation of drum 47-2 to sequentially control the energization of modules 35-8 through 35-12. The start pulse or pulses for operating latch relay 44-2 are produced by the operation of both the drum 47-1 and data source and the sync signals to operate stepping motor 48-2 are produced by the data source 40, as will be described in detail below. Thus the rotation of both drums 47-1 and 47-2 is fully synchronized. If desired, the two reader drums 47-1 and 47-2 may be placed on a common shaft so that only a single motor 48, latch and latch relay 44 will be needed. However, the latter arrangement does not facilitate modularization of the word unit 30 so that a plurality of these units may be readily connected together to increase the message capacity.

Transfer device 53 also etfectively erases the last set of signals from drum 47-1, which were previously used to operate module 35-6, to permit a new set to be stored to control module 35-1. Thus, there is a continuous transition of the sets of signals from word unit 30-1 to word unit 30-2 so that the message flows steadily. This arrangement can be extended for additional word units as desired.

One embodiment of data and sync source 40 for producing the composite signal of FIGURE 4 is described in detail below. This embodiment uses a keyboard to select a desired character, in the manner of a typewriter or teletypewriter, and a plurality of rotating drums. Each drum has a plurality of light transmissive openings therein in predetermined patterns which pass under a respective bank of photoconductive switches. The openings in the drums are made to selectively emit light so that the composite signal of FIGURE 4 may be produced for any desired character.

FIGURE 5 is a developed view of one of the rotatable drums 60 used for producing the composite signals of FIGURE 4. Three such drums are provided, each having diiferent patterns of openings therein. Since the drums are similar, only one drum 60-1 is described in detail. Drum 60-1 has an opaque outer surface provided with a plurality of tracks having a number of light transmissive openings therein in a predetermined pattern. Illustratively, fifteen tracks of openings are provided for producing various types of start, sync and character information. Each track is divided into twenty-two portions, corresponding to the twenty-two periods of the timing cycle of FIGURE 4 and openings 61 of a half period (space) duration are made at predetermined places in certain of the tracks. The length of each of the openings 61 corresponds to the time and one-half a period during rotation of the drum and each opening is spaced on the drum at a position corresponding to the first or second half of the period (odd or even numbered space) to produce a signal at that time. As shown, each track extends for a full 360 around the periphery of the drum.

Each drum may be provided with as many tracks per section and openings per track as needed. As shown in FIGURE 5, the drum is provided with a start track 605T, a sync track 60SY, and thirteen information tracks 601. Each information track has a pattern of openings 61 cut therein corresponding to the pulses to be produced to form the information code of FIGURE 4, line D.

Located under each track of openings is a separately energized and stationary light source, or sources, which is shielded from the light sources of the other tracks by any suitable means, such as a light bafile. In a preferred embodiment of the invention a glow lamp is preferably positioned adjacent the undersurface of the drum for each track so that each'track has a corresponding lamp as asource. By selectively energizing one or the other of the lamps adjacent a corresponding information code track 60I of the drum, the openings of that track have light passing therethrough as they pass by the energized lamp. This light energizes a photoconductive cell which,

acting as a switch, converts DC. power into signal pulses in a signal processor as the drum is stepped around. The lamps for the sync and start pulse tracks 608T and SY for each drum 60 are energized each time that a lamp for one of the information tracks is energized. This is described in greater detail below.

Each drum has the start, sync and information codes distributed over 360 of its periphery. Starting with the rightmost track of the drum 60-1 being described in FIG- URE 5, a series of openings 61 is provided at the positions corresponding to the first half of each successive period from the fifth through the twenty-second (odd numbered spaces 9 through 43). These openings correspond to the sync pulses. In the second track from the right the first four periods have openings during the first halves of the first four periods (

spaces

1, 3, 5 and 7) for producing the start pulses. If desired, a continuous opening may be provided for the first seven spaces. The first thirteen information tracks 60I from the left have openings therein during the second halves of the fifth through twenty-second periods (even numbered spaces 10 through 44) in a predetermined pattern corresponding to the information for various characters. As shown in FIGURE 5 the patterns of openings in the thirteen information tracks correspond to a period and the letters A through L.

If desired, a track containing auxiliary information, called a spare track, may be provided. This spare track (not shown) may have any desired pattern of openings provided therein. It may be used for an end of character signal, additional sync pulses, end of line, end of message pulse signals, etc. It should be noted that in the preferred embodiment of the invention being described that periods twenty through twenty-two of the frame time are not used for character information since only a fifteen element character module is utilized. These three periods may be used for spare information. Also, the spare information may be inserted into the other periods and readily distinguished by the use of suitable modulation techniques for the spare signals.

It should be understood that the other two drums are formed in a manner similar to that of FIGURE 5. However, in these drums the pattern of openings in the information code tracks 601 correspond to the signals needed to reproduce the other characters M through Z, the numerals 1 through 9, and miscellaneous characters and punctuation. The patterns of openings (for the start, sync and spare tracks, if one is used, are the same.

The drum 60-1 of FIGURE 5 has twenty-two periods so that each step of the drum by a stepping motor is approximately 16.36 to produce a full 360 rotation in twenty-two steps. As the drum 60-1 is stepped around, the illuminated openings of one track having the information for the character selected to be reproduced at a module 35, in addition to the illuminated openings of the tracks for the start and sync pulse information, pass underneath a bank of photoconductive ceils 65. The selected character information, in addition to the information for the start and sync pulse, is read out by the photo conductive cells which form part of a signal processor for converting the information read by the cells into the composite signal of FIGURE 4.

FIGURE 5A shows an arrangement for energizing the light sources of a drum. Only a few of the light sources for one of the drums 60 is shown and it should be understood that the energizing arrangement applies to all of the light sources of all of the drums, In FIGURE 5A a lamp 63 is located within the drum adjacent the start track 605T while a lamp 65 is located in the drum adjacent the sync track 60SY. A separate lamp 68. through 68-L is located in the drum adjacent each one of the character information tracks 60I.

The

various lamps

63, 65 and 68 are stationary and are located at positions within the drum so that light produced thereby shining through a respective opening 61 in a track adjacent an illuminated lamp impinges upon a corresponding photoconductive cell located opposite each track in a detector bank 651. Adjacent the start track is a photoconductive cell 73; adjacent the sync track is a photoconductive cell 75; and adjacent the information track corresponding to the characters are respective photoconductive cells 79. through 79-L.

Only two lamps 68. and 68-L are shown for the character information tracks 601. These two lamps are located within the drum adjacent the two tracks having openings therein in a pattern corresponding to a period and the letter L respectively. The production of the opening patterns was described previously. The other character information tracks (not shown in FIGURE A) have stationary lamps 68-A through 68-K (not shown) located within the drum adjacent the corresponding tracks having patterns of openings therein for the letters A-K. Similarly, a respective photoconductive cell 79A through 79-K is provided in the detector bank 651 opposite the opening patterns for the respective character information tracks corresponding to the letters A through K. A photoconductive cell is also provided adjacent the spare track, if one is used, but neither this cell nor the corresponding lamp or track are shown in FIGURE 5A for the sake of clarity. The outputs of the respective

photoconductive cells

73, 75 and 79 go through a signal processor 90 which forms the composite signal of positive and negative pulses. The processor is described in greater detail below.

As shown in FIGURE 5A, all of the

lamps

63, 65 and 68 for the start, sync and information tracks are wired in parallel directly across the B+ supply and ground. This supply is not shown in any of the drawings or described further but it is formed by any suitable power supply unit, many of which are conventional in the art.

One side of each character information track lamp 68. through 68-L is connected directly to a corresponding lamp trigger line 85. through 85-L. A common trigger line 8585 is connected to one side of each of the

lamps

63 and 65 through the

respective capacitors

66a and 66b and the capaictors are returned to ground by a discharge resistor 67. The other side of the

lamps

63, 65 and 68 are connected in parallel to the B+ supply through line 86 and the contact of a normally closed relay K2. Relay K2 is used to deenergize the illuminated

lamps

63, 65 and 68 at the end of each character frame by removing B+ therefrom. The side of each

lamp

63, 65 and 68 adjacent a respective lamp trigger line 85 is connected through a resistor 70 to a suitable source of reference potential such as ground 71. Since the

various lamps

63, 65 and 68 are stationary, there is no need to use slip rings or a commutator. While the various power supply lines and trigger lines are shown schematically as extending through the drum, they actually go out from the interior of the drum through one open end thereof.

During a character frame time, depending upon which trigger line 85 receives an energizing or trigger signal, the lamp 68 connected to that particular trigger line is illuminated. All of the other character lamps 68 are left dark during the frame time under consideration. Each of the lamps 68-.68L is positioned substantially opposite the corresponding photoconductive cell 79-.-79-L so that when an opening in the drum passes by the selectively illuminated lamp 68, light shines through the opening onto the corresponding photoconductive cell 79. No light emanates from the openings in the drum tracks corresponding to all the other characters whose trigger lines did not receive a trigger signal since the lamps for these tracks are dark. Since

lamps

63 and 65 are triggered on each time one of the lamps 68 is energized, light passes through the openings in tracks 605T and 60SY to the corresponding

photocells

73 and 75 as the drum rotates.

As the drum 60-1 is stepped through 360 in twentytwo steps, the corresponding photoconductive cells adjacent the start and sync tracks and the selectively energized lamp 68 of an information track, each receive a pulse of light whenever an opening in a track passes by an illuminated lamp. The

photoconductive cells

73, 75 and 79 are prefereably of the cadmium sulfide, or other similar, type having a high dark (no light) resistance and a low resistance when light is impinging thereon. Each of the photoconductive cells in the bank 65 is separated by a suitable member 81 or placed in a light-tight housing so that no light is received from an adjacent track.

The photoconductive cells of bank 651 are connected to a signal processor 90. The processor includes a resistor 91 which is connected in series with the B- supply, another reister 91a and the photoconductive cell 75; a resistor 93 connected in series with the B- supply; another reistor 93a and photoconductice cell 73; and a third resistor 95 connected in series with the B supply, another resistor 95a and the parallel connected photocells 79-. through 79-L. If desired, and if placing too many cells 79 in parallel lowers the overall resistance too much, then the cells 79 can be split up into banks and connected to separate resistors 95 whose output leads would be connected together.

Each time a photoconductive cell receives a pulse of light through an opening of the moving drum the resistance of that cell decreases to a relatively low value. This completes the series circuit for the corresponding

connected resistor

91 or 93 or 95 to the B- supply and permits current to fiow through the resistor thereby producing a positive going voltage drop across the resistor. The magnitudes of the voltages supplied from the B- source are selected, such as by the use of suitable voltage divider resistors, to produce the proper magnitude output pulses across the

resistors

91, 93 and 95. Thus, positive going pulses, corresponding to the sync pulses, are produced at the upper end of resistor 91 during the first half of each of the fifth through twenty-second periods; positive going pulses, corresponding to the information code, are produced at the upper end of resistor 95 during the second half of each of these periods when an opening appears in an information track 601; and positive going pulses, corresponding to the start pulses, are produced across resistor 93 during the first half of each of the first four periods.

As shown in FIGURE 5B the upper end of the resistor 91, having positive going pulses thereon for the sync, is applied to a follower type amplifier a whose output is also positive going pulses. The upper ends of resistors 93 and having positive going pulses thereon for the start and code information respectively, are connected to a mixer and inverter amplifier 90b. Here, the signals from

resistors

93 and 95 are mixed together and inverted into negative going pulses. The positive going sync pulses from follower amplifier 90a and the negative going start and information code pulses from inverter mixer amplifier 90b are applied through respective relay contacts Kla and Klb to the inputs of a non-inverting mixer 900. The two input signals are mixed here without inversion and the composite output signal of FIGURE 4 line D is produced at the mixer 90c output.

It should be understood that three drums and three detector cell banks 65, similar to those described in FIG- URES 5 and 5A, are provided. The patterns of openings for the character information tracks 601 of drum 60-2 and 60-3 are different and correspond to the letters I through Z, the numbers 1 through 9, and any miscellaneous punctuation desired. Each drum 60 has a sync and start track. Since three drums are utilized, the character information for drum 60-1 may correspond, for example, to a period and the letters A-L; for drum 60-2 to the letters M-Y; for drum 60-3 to the letter Z, numbers 1 through 9, and any miscellaneous punctuation. Of course, there is no need to place the opening patterns in alphabetical 0r numerical order on each of the drums as described above. Any suitable arrangement may be used and the characters, including letters, numerals and punctuation, may be mixed on each drum in any desired manner to facilitate the switching circuits needed to selectively trigger one of the lamps 68 during any one character frame time. It should also be understood that the track capacity for each drum may be selected as desired to increase or decrease the number of drums 60 needed to produce all of the desired characters.

Each of the drums 60-2 and 60-3 also has a corresponding cell bank 6-5-2 and 65-3. These cell banks are similar to bank 65-1 and the photoconductive cells therein are all connected to the signal processor 90 in parallel with the corresponding photoconductive cells of the other cells banks. If desired, a separate processor 90 can be used for each cell bank and the outputs thereof connected in parallel to the inputs of the amplifiers in the processor 90.

FIGURE 6 shows one form of data source 40 for selectively energizing the lamps 68 of the drum 60 of FIGURE A by a keyboard arrangement 110. Here, the keyboard 110 is provided with a plurality of spring loaded double-pole double-throw switches 112-1 112-n whose movable center arms are mechanically ganged together. As many switches 112 are provided as are needed to select the individual characters for reproduction by the indicator modules, with some of the switches being able to selectively energize two lamps 68 in order to increase the capacity of the keyboard without making the number of switches 112 unwieldy.

The contact of the center movable arm of the right-hand half of each switch 112 is connected to the one end of a respective capacitor 118-1 118-n, whose other ends are all connected to the upper end of a resistor 119 and diode 119a connected in parallel. The lower end of the resistor-diode network returns to ground. With each movable center arm of the righthand half of a switch 112 in its normal rest position engaging the right-most stationary switch contact, the respectively connected capacitor 118 charges to a B- potential over a line 120 connected to all of the right-most stationary switch contacts.

Each time one of the switches 112 is depressed, the right-most center arm is moved to the adjacent left stationary contact. This produces a trigger spike at the resistor-diode network 119-119a which is conveyed over line 116 to a relay amplifier 115. Diode 119a prevents negative going spikes from reaching the amplifier by passing such spikesto ground. The relay amplifier 115 controls the energization of a relay K1 to start a cycle of production of the composite signal.

The left stationary contact of the right-hand section of each switch 112 is connected to a respective lamp trigger line 85. Hence, when a selected switch 112 is depressed, the negative change on the respectively connected capacitor 118 is applied directly to one side of the connected lamp 68 adjacent the selected character code track 601. The left-most contact of the left hand section of each switch is connected over line 120 to the B- supply while the center movable contact of the same section of each switch is connected to the sync start trigger line 8555 of one of the drums 60. As shown, the upper bank of switches go to line SSSS-l of drum 60-1, the middle bank to line 85SS-2 of drum 60-2, and the lower bank to line 85SS-3 of drum 60-3. Of course, any suitable wiring arrangement may be used as a matter of choice, but the connected trigger line 8558 must be to the same drum on which is located the lamp 68 for the selected character corresponding to the switch 112 that is depressed. The movable contact of the left switch section applies B directly to a trigger line "8555 when a switch 112 is depressed.

Several of the switches 112 have their respective left stationary contacts on their right hand section connected to the center arm of a relay K3 which is energized by a normally open switch 113. The movable contact of switch 113 is connected to a suitable source of B+ potential 113A having one end thereof connected to ground. When the switch 113 is closed the relay coil of relay K3 is energized and the movable contacts K3-a K3-n are moved between two stationary relay contacts having lamp trigger lines 85 connected thereto. Thus, several of the switches 112 have the capability of selecting two lamp trigger lines 85 depending upon the condition of switch 113, which switch is normally open. Switch 113 corresponds to the shift key of a standard typewriter or teletypewriter keyboard. It should be understood that as many of the switches 112 can be connected for operation with relay K3 as desired, thereby giving each switch so connected the capability of selecting two trigger lines, corresponding to two characters, in accordance with the condition of switch 113.

The three data source drums 60-1, 60-2, and 60-3 are rotated on a common shaft 147 by a stepping type motor 148. Motor 148 may be, for example, of the type designated Slo-Syn, manufactured by Superior Electric Company. Motor 148 is adjusted to step 360 in 22 steps in response to switching pulses produced by a pulse generator switching pulses produced by a pulse generator 142. If desired, a continuously rotating motor may be used with a suitable arrangement, such as a ratchet and pawl, for producing stepping action.

The operation of the data source of FIGURE 6 is as follows. Moving the center ganged arms of any of the switches 112 to the left applies a positive trigger from the resistor-diode network 119-119a onto line 116 to energize a relay amplifier 115. When amplifier is made conductive it energizes relay K1 thereby lifting a mechanical stop out of a notch 131 provided on a disc 132-1 which is connected to and rotatable with the common shaft 147 of drums 60. The stop 130 would normally serve to prevent the drums 60 from rotating unless this stop was taken out of the notch 131. The notch 131 is in registry with the 0 point of each drum 60, i.e., the notch is aligned with the beginning of the start track of each drum.

When relay K1 is energized the composite signal line contacts Kla and Blb of the processor 40 (FIG. 5) are closed as well as a lower contact K10. The lower contact Klc applies a trigger spike from a resistor 141 and capacitor 141a over line to a triggered pulse generator 142 which controls the operation of the stepping motor 148. Once generator 142 starts to produce the pulses, which occurs upon application of a trigger over line 140, stepping motor 148 operates and starts to rotate the drums. Upon rotation, the mechanical stop 130 lifts up on the outer periphery of the disc 132-1 and the contacts of relay K1 remain closed during the 360 rotation of the drums until the stop 130 falls back into the notch 131. Because of this mechanical closing of relay K1 contacts it is not necessary to keep relay amplifier 115 conductive.

As a switch 112 has its center arms moved into contact with the respective left stationary contacts, its respective capacitor 118 is discharged through resistor 119. As explained above, this energizes K1 through relay amplifier 115 and lifts the mechanical stop 130 setting the pulse generator 142 into operation. At the same time B- voltage is applied directly from the leftmost stationary contact to the trigger line 8588 connected to the center contact of the actuated switch. This causes

lamps

63 and 65 connected to the energized trigger line 85SS to fire, Also, the charge on the respective capacitor 118 of the actuated switch 112 is connected via the center arm of the right half switch section to the left stationary contact of the same section of the switch 112 and through this contact to the connected lamp trigger line 85 and corresponding lamp 68 selected by the particular switch 112 which was operated. The pulse discharge of a capacitor 118 causes the lamp 68 connected to the trigger line 85 receiving the pulse to fire. It should be understood that the B+ applied to one side of a lamp 68 through relay K2 is not sufiicient to fire the lamp but is sufficient to maintain it once the lamp is fired. However, the combination of pulse polarity potential produced by discharge capacitor 118 when applied to a selected trigger line 85 onto one side of a selected lamp bank and the B+ bias applied to the other side of the lamp causes it to fire.